Abstracts of Current Literature

Abstracts of Current Literature

VASCULAR Diagnosis

Management of Small Abdominal Aortic Aneurysms: Early Surgery vs Watchful Waiting. David A. Katz, Ben- jamin Littenberg, Jack L. Cronenwett. JAMA 1992; 268:2678-2686. (D.A.K., Department of Medicine [111Bl, Veterans Administration Medical Center, White River Junction, VT 05001)

Objectiue. To compare two clinical strat- egies for the management of small abdominal aortic aneurysms (AAAs) less than 5 cm in diameter: early surgery (repair small AAAs when diagnosed) and watchful waiting (measure AAA size every 6 months and repair when the diameter reaches 5 cm). Data Sources. The authors reviewed data from an earlier longitudinal study of patients with small AAAs to estimate incidence rates of rupture or acute expansion. Estimates for other parameters in the model were obtained by searching the medical literature (MEDLINE, 1966 to present). Data Synthe- sis. The authors constructed a Markov decision tree to compare early surgery with watchful waiting in patients with asymp- tomatic AAAs less than 5 cm in diameter, with respect to long-term survival in quali- ty-adjusted life years. The average annual rates of rupture or acute expansion for AAAs with a maximal transverse diameter of less than 4.0, 4.04.9, and at least 5.0 cm, are 0,3.3, and 14.4 events per 100 patient- years of observation, respectively. At an average rupture rate of 3.3 events per 100 patient-years and an average operative risk for elective surgery (4.6%, 30-day mortality), this model predicts that early surgery improves survival in patients who present with a 4-cm AAA. The benefit of early surgery decreases with increased age at presentation. If the average rupture rate for AAAs less than 5 cm is assumed to be low (eg, 0.4 event per 100 patient-years), watchful waiting is favored, particularly as operative risk increases. The decision in this subgroup, however, is sensitive to possible future increases in operative risk. Conclusions. In the majority of scenarios that the authors examined, early surgery is preferred to watchful waiting for patients with AAAs less than 5 cm in diameter. Watchful waiting is gener- ally favored, however, for patients with a low risk of AAA rupture or acute expansion,

including those patients who present with very small AAAs (eg, < 4 cm). More accurate data concerning the rupture risk of AAAs less than 5 cm would improve clinical decision making. AUTHORS' ABSTRACT

A Low-Molecular-Weight Heparinoid Compared with Unfractionated Hep- arin in the Prevention of Deep Vein Thrombosis in Patients with Acute Ischemic Stroke: A Randomized, Double-Blind Study. Alexander G. G. Turpie, Michael Gent, Robert Cote, e t al. Ann Intern Med 1992; 117:353-357. (A.G.G.T., HGH-McMaster Clinic, Hamil- ton Civic Hospitals, General Division, 237 Barton S t E, Hamilton, Ontario, Canada L8L 2x2)

Objectiue. To compare the relative safety and efficacy of a low-molecular-weight heparinoid (ORG 10172) with unfractionated heparin in the prevention of deep vein thrombosis in patients with acute ischemic stroke. Design: Double-blind randomized trial. Setting: Seven Canadian university- affiliated hospitals. Participants: Eighty- seven patients with acute ischemic stroke resulting in lower-limb paresis. Znteruen- tion: Patients received either low-molecular- weight heparinoid, 750 anti-factor Xa units twice daily, or unfractionated heparin, 5,000 units subcutaneously twice daily. Treatment was continued for 14 days or until hospital discharge if sooner. Measurements: Deep vein thrombosis was diagnosed with iodine- 125-labeled fibrinogen leg scanning and im- pedance plethysmography. Venography was indicated if either test was positive. Overt hemorrhage, major or minor, was assessed clinically. Results: Venous thrombosis occurred in four patients (9%) given low-molecular-weight heparinoid and in 13 patients (31%) given heparin (relative risk reduction, 71%; 95% confidence interval, 16%-93%). The corresponding rates for proximal vein thrombosis were 4% and 12%, respectively (relative risk reduction, 63%; P > .2). The incidence of hemorrhage was 2% in both groups. Conclusion: Low-molecular-weight heparinoid, given in a fixed dose of 750 anti- factor Xa units subcutaneously twice daily, is more effective than subcutaneous low- dose heparin for the prevention of deep vein thrombosis in patients with acute ischemic stroke. AUTHORS' ABSTRACT

Deep-Vein Thrombosis and the Inci- dence of Subsequent Symptomatic Cancer. Paolo Prandoni, Anthonie W. A. Lensing, Harry R. Biiller, e t al. N Engl J Med 1992; 327:1128-1133. (A.W.A.L., Centre for Haemostasis, Thrombosis, Atherosclerosis, and Inflammation Re- search, Academic Medical Centre F4-237, Meibergdreef 9,1105 AZ Amsterdam, The Netherlands)

Background: In contrast to the established relation between overt cancer and subsequent venous thromboembolism, it is unclear whether symptomatic deep-vein thrombosis is associated with a risk of subsequent overt malignant disease. Meth- ods: Two hundred sixty consecutive patients with symptomatic, venographically proved deep-vein thrombosis were enrolled in a study, of whom 250 were followed during a 2-year period. Among those assessed during follow-up, the incidence of subsequently detected cancer in the 105 patients with secondary venous thrombosis (ie, thrombosis associated with a well-recognized risk factor other than cancer) was compared with the incidence of cancer in the 145 patients with idiopathic venous thrombosis. Results: Rou- tine examination at the time of diagnosis of the venous thrombosis revealed cancer in five of the 153 enrolled patients with idiopathic venous thrombosis (3.3%) and in none of the 107 enrolled patients with secondary venous thrombosis. During follow- up, overt cancer developed in two of the 105 patients with secondary venous thrombosis (1.9%) and in 11 of the 145 patients with idiopathic venous thrombosis (7.6%; odds ratio, 2.3; 95% confidence interval, 1.0-5.2; P = 0.043). Of the 145 patients with idiopathic venous thrombosis, 35 had confirmed recurrent thromboembolism. Overt cancer subsequently developed in six of the 35 (17.1%). The incidence of cancer in the patients with recurrent idiopathic venous thrombosis was higher than that in the patients with secondary venous thrombosis (P = ,008; odds ratio, 9.8; 95% confidence interval, 1.8-52.2) or in the patients with idiopathic venous thrombosis that did not recur (P = ,024; odds ratio, 4.3; 95% confidence interval, 1.2-15.3). Conclusions: There is a statistically significant and clinically important association between idiopathic venous thrombosis and the subsequent development of clinically overt cancer, especially among patients in whom venous thromboembolism recurs during follow-up.

320 Journal of Vascular and Interventional Radiology

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Atherosclerotic Plaque Hemorrhage and Rupture Associated with Cre- scendo Claudication. Michael Mecley, Kenneth Rosenfield, Jenifer Kaufman, e t al. Ann Intern Med 1992; 117:663-666. (Jeffrey M. Isner, S t Elizabeth's Hospital, 736 Cambridge St, Boston, MA 02135)

Unstable atherosclerotic plaque morphology has been established as the major factor responsible for escalating symptoms of myocardial ischemia and extracranial vascular disease. Previous histopathologic and ultrasound (US) studies have suggested that plaque hemorrhage, plaque rupture, and intraluminal thrombosis characterize the sequence of pathologic findings in such cases. Surprisingly, however, this same sequence of unstable plaque morphology has not been previously recognized as a basis for accelerated symptoms of arterial insuffi- ciency in patients with peripheral vascular disease. The evidence the authors obtained by directional atherectomy and intravascu- lar US suggests that unstable plaque morphology should be considered as a pathoge- netic mechanism for accelerated or crescendo claudication. AUTHORS' ABSTRACT

Associated Aortic Rupture-Pelvic Fracture: An Alert for Orthopedic and General Surgeons. M. Gage Ochsner, Andrew P. Hoffman, Doreen DiPasquale, e t al. J Trauma 1992; 33: 429-434. (Howard R. Champion, Trauma Service, Department of Surgery, Wash- ington Hospital Center, 110 Irving S t NW, Washington, DC 20010)

Blunt trauma patients with pelvic fractures have been shown to have a twofold to fivefold increased risk of aortic rupture compared with the overall blunt trauma population. A retrospective review was performed to determine whether the relationship between aortic rupture and pelvic fracture could be further delineated using a pelvic fracture classification based on mechanism of injury. Of 4,157 consecutive blunt trauma patients, 371 (8.9%) had pelvic fractures, 34 (0.8%) had ruptured thoracic aortas, and 12 had both injuries. When pelvic fractures were classified according to vector of force, 10 of 12 (83%) aortic ruptures occurred in patients with an anterior-posterior compression fracture pattern, an incidence of aortic rupture eight times greater than that of the overall blunt trauma population. There was no increased incidence of aortic rupture among patients with any other pelvic fracture pattern. The authors conclude that the previously reported association between aor-

tic rupture and pelvic fracture can be further specified to include, predominantly, those patients with an anterior-posterior compression fracture pattern. AUTHORS' ABSTRACT

Pitfalls in the Use of Color-Flow Du- plex Ultrasound for Screening of Suspected Arterial Injuries in Pene- trated Extremities. Jack M. Bergstein, Jean-Francois Blair, Janis Edwards, e t al. J Trauma 1992; 33:395-402. (J.M.B., 8700 W Wisconsin Ave, Box 205, Milwau- kee, WI 53226)

The authors compared color-flow duplex ultrasonography with arteriography in 67 patients who sustained 75 penetrating injuries to the extremities without obvious arterial injury. There were 72 negative and three (4.0%) positive studies and no failed at- tempts. With arteriography as the "gold standard," color-flow duplex scanning had a specificity of 99% and a sensitivity of 50%, positive and negative predictive values of 66% and 97%, and an accuracy of 96%. Small pseudoaneurysms were missed in an axillary and an aberrant radial artery, and a genicular artery pseudoaneurysm was mis- read as originating from the popliteal artery. Cautious interpretation of negative studies appears warranted, particularly in the axilla and in bifurcated arteries. Extremity arteries should be completely imaged to rule out aberrant anatomy. Questionable studies should be confirmed ai-teriographically. With these caveats, color-flow duplex scanning may be useful for screening extremities with penetrating injuries thought to harbor occult arterial injuries. AUTHORS' ABSTRACT

Duplex Ultrasonography versus Ar- teriography in the Diagnosis of Arte- rial Injury: An Experimental Study. Thomas F. Panetta, John P. Hunt, Ken- nan J. Buechter, e t al. J Trauma 1992; 33:627-636. (T.F.P., Division of Vascular Surgery, Montefiore Medical Center, 11 1 E 210th St, New York, NY 10467)

Duplex ultrasonography (dUS) and arteriography were evaluated in an experimental model of arterial trauma in order to determine their relative accuracy and to define the characteristic US features of arterial injuries. Occlusions (n = 19), blunt injuries (n = 24), lacerations (n = 25), arteriovenous fistulae (n = 13), or no injuries (sham, n = 19) were surgically created in the femoral and carotid arteries of 25 dogs. Following closure of the incisions, duplex US was performed and interpreted by a staff vascular

surgeon without knowledge of the presence or type of injury. Biplane selective arterio- graphic studies were evaluated by an independent stafTradiologist. Although duplex US and arteriography were equally accurate in evaluating arterial injuries, duplex US was more sensitive (90.1% 2 3.3% vs 80.2% 2 4.4%, P = ,002) and better at identifying lacerated arteries (P = ,011. How- ever, arteriography had greater specificity (94.7% 2 5.1% vs 68.4% + 10.7%, P = .04) and was more accurate for identifying normal arteries ( P = ,041. The validity of duplex US increased in the latter half of the study, thus demonstrating a learning curve. Du- plex US was a more sensitive screening mo- dality than arteriography for evaluating arterial injuries in this experimental model, thereby supporting its use in clinical trials to evaluate its accuracy, reliability, and cost- effectiveness in the trauma setting. Further- more, management decisions can be based on the specific type of injury, pathologic condition of the arterial wall, and hemodynamic factors identified by duplex US. Clinically occult arterial injuries can be followed with repeated duplex US to define their natural history. AUTHORS' ABSTRACT

Venous and Arterial Anomalies of the Lower Extremities Diagnosed by Duplex Scanning. Thomas M. Kerr, J . Michael Smith, Peter McKenna, e t al. Surg Gynecol Obstet 1992; 175:309-314. (T.M.K., Vascular Laboratory, Veterans Administration Medical Center, Bay Pines, FL 33504)

The complex embryologic development of the vascular system often results in a myriad of clinically relevant anomalies. It has been stated that the classic anatomic venous pattern in the lower extremity is found in only 16% of patients. Previous studies on this topic are limited to isolated venous dissections or phlebography that lack complete anatomic detail. The recent intro- duction of high-resolution duplex scanners for the assessment of veins of the lower extremity provides a unique opportunity to determine the incidence of anatomic varia- tion. The current prospective study was done to identify venous or arterial anomalies apparent during routine duplex scanning of the lower extremity performed to rule out deep venous thrombosis (DVT). Limbs that had evidence of acute or chronic extensive DVT were excluded. Of 1,600 consecutive extremity scans, 946 extremities (59%) had no evidence of DVT. Of these, there were 43 patients with 64 anomalies in 57 extremi-

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ties. The mean age of the group was 53.4 years. There were 24 women (55.8%) and 19 men (44.2%). There were 59 (92.2%) venous and five (7.8%) arterial anomalies. Duplica- tion of the superficial femoral vein was the most common anomaly noted. Duplication of the deep femoral and popliteal vein was also noted. Unilateral anomalies were more common than bilateral anomalies, namely 67.4% versus 32.6%, respectively. Pain and swell- ing, common complaints in the patients with an anomaly, were noted in 71.4% and 45.7%, respectively. The frequency of deep venous anomalies of the lower extremities may be less than previously reported. Knowledge concerning the incidence and distribution of venous anomalies may lead to improved assessment and treatment of venous disease. AUTHORS' ABSTRACT

Effects of Angiographic Needle Size and Subsequent Catheter Insertion on Arterial Walls: An In Vitro Exper- iment in Human Cadavers. Douglas C. Smith, Jefferson A. Hamlin, Dag A. Jensen, et al. Invest Radio1 1992; 27:763- 767. (D.C.S., Department of Radiology, Loma Linda University Medical Center, 11234 Anderson St, Loma Linda, CA 92354)

Rationale and Objectives. It is widely believed that downsizing catheters, and pos- sibly needles, will decrease damage to the entry vessel in the performance of angiography. The purposes of this in vitro experi- ment are to determine if smaller needles produce less arterial wall damage than larger needles and to assess the influence of subsequent catheter insertion. Meth- ods. Each iliac artery pair from 35 fresh human cadavers was punctured three times with an 18-g needle and three times with a 21-g needle, for a total of 210 punctures. In two of each set of three, a 5- or 7-F dilator was passed. One hundred ninety-eight puncture tracts were usable and examined micro- scopically. They were graded on a scale of 1-3 in each of four categories: size of tract, margin irregularity, approximation of edges, and shape of tract. Results. A X 2 analysis of the grading scores showed a significant shift of cases into lower damage grades when the smaller-gauge needle was used for initial punctures (P < ,0005). The subsequent insertion of a dilator, however, imposed further damage, such that the initial differ-

ences due to needle gauge were obliterated (P > .2). Conclusion: These data indicate that a 21-g needle produces less arterial wall damage than an 18-g needle, but that any safety conferred by the smaller needle is eliminated by the subsequent insertion of a 5- or 7-F catheter. AUTHORS' ABSTRACT

Angioplasty, Atherectomy, Lasers

Training Standards for Physicians performing Peripheral An&oplasty and Other Percutaneous Peripheral Vascular Interventions: A statement for Health Professionals from the Special Writing Group of the Coun- cils on Cardiovascular Radiology, Cardio-thoracic and Vascular Sur- gery, and Clinical Cardiology, the American Heart Association. David C. Levin, Gary J. Becker, Gerald Dorros, e t al. Circulation 1992; 86:1348-1350. (Of- fice of Scientific Affairs, American Heart Association, 7272 Greenville Ave, Dallas, TX 75231-4596)

After summarizing the background of their ad hoc committee and defining diagnostic angiography and percutaneous angioplasty, the authors of this American Heart Association position statement describe minimum training standards to be met by physicians seeking to perform peripheral interventions. These standards include a basic body of knowledge regarding the natural history, diagnosis, and treatment of peripheral vascular disease; basic training in radiology, vascular or cardiovascular medicine, or vascular surgery; procedural training and experience; and maintenance of privileges. Procedural training may be by formal fel- lowship, experience, or apprenticeship. All such training must include performance of a minimum of 100 diagnostic angiograms and 50 percutaneous angioplasty procedures, for at least half of which the applicant was the primary operator, and participation in at least 10 cases involving peripheral thrombo- lytic therapy. DAVID M. WILLIAMS, MD University Hospitals Ann Arbor, Mich

Therapeutic Dissection after Suc- cessful Coronary Balloon Angioplas- ty: No Influence on Restenosis or on Clinical Outcome in 693 Patients. Walter R. M. Hermans, Benno J . Rensing, David P. Foley, e t al. J A m Coll Cardiol 1992; 20:767-780. (Patrick W. Serruys, Catheterization Laboratory, Thorax- center, Erasmus University Rotterdam, Box 1738,3000 DR Rotterdam, The Neth- erlands)

Objectiues. The objective of this study was to examine the relation between an angiographically visible coronary dissection immediately after successful coronarv balloon angiop"lasty and a subsequent restenosis and long-term clinical outcome. Back- ground. The study population comprised all 693 patients who participated in the MER- CATOR trial (randomized, double-blind, placebo-controlled restenosis prevention trial of cilazapril, 5 mg two times a day). Meth- ods. Cineangiographic films were processed and analyzed in a central angiographic core laboratory, without knowledge of clinical data, with use of an automated interpolated edge detection technique. Dissection was judged according to the National Heart, Lung, and Blood Institute classification. An- giographic follow-up was obtained in 94% of patients with 778 lesions. Two approaches were used to assess the restenosis phenome- non: categoric, using the traditional cutoff criterion of > 50% diameter stenosis at follow-up, and continuous, defined as absolute change in minimal lumen diameter (in milli- meters) between the postcoronary angioplasty and follow-up, adjusted for the vessel size (relative loss). Clinical outcome was ranked according to the most serious adverse clinical event per patient during the 6-month follow-up period, ranging from death, nonfatal myocardial infarction, coronary revascularization and recurrent angina requiring medical therapy to none of these. Results. Dissection was present in 247 (32%) of the 778 dilated lesions. The restenosis rate was 29% in lesions with and 30% in lesions without dissection (relative risk 0.97; 95% confidence interval, 0.77-1.23). The relative loss in both groups was 0.10 (mean difference, 0; 95% confidence interval, -0.03 to 0.03). Clinical outcome ranged from death in four patients (0.9%) without dissection and one patient (0.4%) with dissection to nonfatal myocardial infarction in four (0.9%) without and eight (3.2%) with dissection, coronary revascularization in 73 (16.6%) without and 32 (12.7%) with dissection, recurrent angina requiring medical therapy in 88 (20%) without and 47 (18.7%)


March-April 1993

with dissection, and no serious adverse event in 272 (61.7%) without and 114 (65.1%) with dissection. Conclusions. These data indicate that a successfully dilated coronary lesion with an angiographically visible dissection is no more likely to develop restenosis, and is not associated with a worse clinical outcome at 6-month follow-up than is a dilated lesion without visible dissection on the postangioplasty angiogram. AUTHORS' ABSTRACT

Coronary Angioplasty Performed with Gradual and Prolonged Infla- tion Using a Perfusion Balloon Cath- eter: Procedural Success and Reste- nosis Rate. Alan N. Tenaglia, Peter J. Quigley, Dean J. Kereiakes, e t al. Am Heart J 1992; 124:585-589. (A.N.T., Car- diology Section, SL-48, Tulane University Medical Center, 1430 Tulane Ave, New Orleans, LA 70112-2699)

The results of routine coronary angioplasty using gradual and prolonged balloon inflation with a perfusion balloon catheter were evaluated. One hundred forty patients were treated with inflation of the balloon to 6 atm over 3 minutes, with a median inflation time of 15 minutes. The procedural success rate (residual stenosis I 50%) was 99%. In-hospital major complications occurred in five patients (3.6%), with one patient experiencing a periprocedural infarction, three patients requiring bypass surgery for abrupt closure, and one patient dying after elective bypass surgery following previous successful angioplasty of a culprit lesion. The restenosis rate in the 117 patients with angiographic follow-up (87% of those eligi- ble) was 42%. Thus, gradual and prolonged inflation using a perfusion balloon catheter resulted in a high procedural success rate and a restenosis rate similar to that reported in large studies of patients treated with standard angioplasty. These results warrant further study using a prospective randomized trial design. AUTHORS' ABSTRACT

Coronary Angioplasty of Chronic Oc- clusions: Factors Predictive of Pro- cedural Success. Luigi Maiello, Antonio Colombo, Renato Gianrossi, e t al. Am Heart J 1992; 124:581-584. (L.M., Centro Cuore Columbus, Via Buonarroti 48, 20149 Milan, Italy)

In a retrospective study of 365 chronic total occlusions that were submitted for angioplasty, the authors studied the influence of 27 clinical, morphologic, and procedural variables as possible predictors of successful

outcomes. Success rate was shown to be significantly influenced by the following variables: operator experience (41% in early patients, first 6 months; 73% in late patients, last 6 months of entire series; P < .001), duration of occlusion ( I 1 month, 89%; 1-3 months, 87%; 1 3 months, 45%; unknown, 60%; P < .001), morphology of occlusion (tapered, 83%; abrupt, 51%), length of occlusion ( 5 15 mm, 71%; > 15 mm, 60%; P < .001), and bridging collaterals (present, 29%; absent, 67%; P < ,001). None of the other clinical, angiographic, or procedural variables correlated with the success rate of coronary angioplasty. The calculated probability for an experienced operator ( > 100 occlusions attempted) to successfully open an occlusion with favorable morphology ( I 1 month old, short, tapered, without bridging collaterals) is 99%. An attempt by the same operator to open an occlusion with unfavor- able structure ( 2 3 months old, long, unta- pered. has only 47% probability of success. The probability increases to 84% when the occlusion is tapered. The authors concluded that in addition to the duration and the length of occlusion, tapered morphology, bridging collaterals, and operator experience can predict successful angioplasty in chronic total coronary occlusion. AUTHORS' ABSTRACT

Surgical Standby for Coronary Bal- loon Angioplasty. Bernhard Meier, Philip Urban, Pierre-Andre Dorsaz, e t al. JAMA 1992; 268:741-745 (B.M., Cardiol- ogy Center, University Hospital, 1211 Geneva 14, Switzerland)

Objective. To assess the predictability of need for emergency surgery after coronary balloon angioplasty. Design. Nonrandom- ized intervention study. Setting. Nonprofit university hospital. Patients. Prior to balloon angioplasty, 1,000 consecutive patients were assigned to either the "standby" group (189 patients [19%1) or the "no-standby" group (811 patients [81%1). Patients in the standby group (intervention coordinated with cardiac surgery) included all operable patients undergoing angioplasty of their largest coronary arteries that were not currently or previously totally occluded or col- lateralized; the no-standby group consisted of the remainder of patients. Interuention. Allocation to coronary angioplasty with or without surgical standby. Main Outcome Measures. Need for bypass surgery, occur- rence of myocardial infarction, and mortality from complications of angioplasty. Re- sults. Bypass surgery immediately after angioplasty was done in one patient in each

group (standby, 0.5%; no-standby, 0.1%). The frequency of infarction was 5% versus 4%, respectively. All eight deaths occurred in the no-standby group (1.0%), but none of them were consequences of a lack of surgical standby. They occurred in situations in which bypass surgery would not have changed the outcome (two cardiac failures late after technically successful angioplasty for postinfarct cardiogenic shock, one in- laboratory rupture of an unrecognized ventricular pseudoaneurysm, and one prot- amine reaction), secondary to acute problems late after successful angioplasty (two sudden deaths and one vessel occlusion in an inoperable patient), or despite surgery (one patient with left main stem dissection). Conclusions. Performing roughlv 80% of - - " coronary angioplasties without surgical standbv did not increase ~ a t i e n t risk. Coro- nary angioplasty without surgical backup, albeit not an ideal setting, appears ethically feasible in selected patients if dictated by logistic considerations. AUTHORS' ABSTRACT

Restenosis after Directional Coro- nary Atherectomy: Effects of Lumi- nal Diameter and Deep Wall Exci- sion. Richard E. Kuntz, Tomaki Hinohara, Robert D. Safian, e t al. Circu- lation 1992; 86:1394-1399. (R.E.K., Car- diovascular Division, Beth Israel Hospi- tal, 330 Brookline Ave, Boston, MA 02215)

Background. Deep wall excision during directional atherectomy has been reported in one study to increase the risk of subsequent restenosis. On the other hand, the authors have observed that the probability of late (6-month) restenosis is reduced by maximizing postprocedure luminal diameter. Although such maximal luminal enlargement by directional atherectomy has not increased procedural complications in their experience, it might well increase the incidence of subintimal (deep wall component) recovery. They performed this study to evaluate the relative influences of luminal enlargement and deep wall component excision on postatherectomy restenosis. Meth- ods and Results. Atherectomy resulted in a 7% + 15% residual stenosis with a less than 0.5% incidence of angiographic vessel perfo- ration. The minimal luminal diameter of each lesion was measured before and after intervention in 413 lesions, 389 (94%) of which had histological analysis of the ex- cised specimens. Specimens were catego- rized by the deepest layer retrieved: type I (recovery of intima alone, n = 141), type I1

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(recovery of media, n = 791, and type I11 (recovery of adventitia, n = 65). Repeated angiographic measurement of minimal luminal diameter was available for 329 (80%) segments 6 months after atherectomy. Com- pared with the 32% restenosis rate for type I excision, there was no increase in restenosis (stenosis > 50%) for type 11, type 111, or types I1 plus I11 (P = .86). Stratification by vessel characteristics also failed to show any association between restenosis and deep wall component recovery in any subgroup, including native coronary (P = ,851, left anterior descending coronary artery (P = .70), right coronary artery (P = ,511, saphenous graft (P = .78), or prior restenosis lesions (P = ,981. Paradoxically, the recovery of adventitia (type I11 excision) was associated with a lower late percentage of stenosis (P = ,031 and a trend toward less restenosis (P = ,111 compared with type I excisions. A multiple logistic regression model was constructed that demonstrated immediate postprocedure luminal diameter (P = ,021 to be an independent determinant of restenosis. In this model, the presence of deep wall components (types I1 plus 111) did not adversely affect (P = .86) restenosis, but the recovery of adventitia was associated with an independent trend toward reduced restenosis (P = .06). Conclusions. The immediate goal of directional atherectomy should be to safely provide the largest lumen possible in order to reduce restenosis. The recovery of deep wall components does not appear to jeopardize the beneficial effect that obtain- ing a large immediate postprocedure lumen diameter has on reducing the incidence of late restenosis. AUTHORS' ABSTRACT

Balloon Angioplasty of the Aorta in Takayasu's Arteritis: Initial and ~ongterm Results. Sanjay Tyagi, Up- kar A. Kaul, Mohan Nair, e t al. Am Heart J 1992; 124:876-882. (S.T., Department of Cardiology, G.B. Pant Hospital, New Delhi 110 002, India)

Percutaneous transluminal balloon angioplasty for stenosis of the aorta was performed in 36 patients with Takayasu's arteritis (age range, 8-36 years; mean, 19.1 years k 7.7). Balloon dilatation was successful in 34 patients and resulted in a decrease in the mean peak systolic pressure gradient (PSG) from 75.2 mm Hg + 29.1 to 24.8 mm Hg 2 19 (P < .001) and a mean increase in the diameter of the stenosed segments from 4.5 mm + 2.2 to 9.6 mm + 3.8 (P < ,001). Hemodynamic and angiographic restudy, which was performed in 20 patients at a

mean follow-up period of 7.7 months + 4.1 (range, 3-24 months), showed a further decrease in PSG ( 2 15 mm Hg) in seven patients (from 40.0 mm Hg k 11.2 to 15.7 mm Hg k 10.2; P < .01), no significant change in PSG in 12 patients (17.1 mm Hg ? 13.6 vs 16.6 mm Hg k 12.7; not significant), and an increase in PSG from 15 to 85 mm Hg in one patient. The patient who showed restenosis underwent successful redilatation. Six patients who underwent late recatheteriza- tion and angiography at 36-60 months (mean, 43 months k 9.4) show continued relief of stenosis (mean PSG, 8.8 mm Hg k 7.8). Patients with short-segment ( < 4-cm) stenosis experience more relief than patients with long-segment ( 4-cm) stenosis (residual PSG, 18.6 mm Hg 2 8.2 vs 40 mm Hg + 16; P < .01). All successfully treated patients experienced improvement in their symptoms and hypertension. There were no significant complications. No patient showed evidence of an aneurysm immediately after percutaneous transluminal balloon angioplasty or during follow-up aor- tography. Percutaneous transluminal balloon angioplasty for stenosis of the aorta in patients with Takayasu's arteritis is safe and highly effective and produces sustained improvement. AUTHORS' ABSTRACT

Dose-dependent Smooth Muscle Cell Proliferation Induced by Thermal Injury with Pulsed Infrared Lasers. Philippe C. Douek, Rosaly Correa, Rich- ard Neville, e t al. Circulation 1992; 86: 1249-1256. (Robert F. Bonner, Bldg 13, Rm 3W13, National Institutes of Health, Bethesda, MD 20892)

Background. Recently, laser-heated and radio-frequency-heated balloon angioplasty techniques have been proposed as a means to treat or minimize dissection and elastic recoil but have been associated with a high rate of clinical restenosis. Similarly, pulsed laser angioplasty techniques proposed to minimize thermal injury while ablating ob- structing atheroma have failed to reduce clinical restenosis. Because "hot balloon" and pulsed laser angioplasty create both mechanical and thermal injury, it has been dif- ficult to discern the cause of the smooth muscle cell (SMC) proliferation resulting in restenosis and whether such magnitude of proliferation is predictable and dose related. This study was undertaken to explore these issues. Methods and Results. Localized thermal lesions accompanying efficient ablation were created with a pulsed [thulium yttrium aluminum garnet] Tm:YAG laser in nine

rabbit aortas, which consistently led to a focal proliferation of SMC that filled the ab- lated region by 4 weeks. Transcutaneous holmium YAG pulsed laser irradiation at multiple independent sites of 24 central rabbit ear arteries without ablation led to brief = 30°C thermal transients and thermal damage to the artery wall resulting in significant neointimal proliferation by 3 weeks and a mean cross-sectional narrowing of 59% k 17% at a dose of 390 mJ/mm2. Acute and chronic responses to varying total energy deposition were studied by histology after the rabbits were killed at 2 hours to 4 weeks. Arterial segments midway between laser injuries were unaffected and served as internal controls. Neointimal proliferation at 3 weeks after laser injury exhibited a clear dose dependence. Mean cross-sectional narrowing increased from 34% k 10% to 85% k

15% as laser fluence increased from 240 to 640 mJ/cm2 (r = .84). Similarly, cross-sectional narrowing caused by SMC neointimal proliferation increased from 20% k 10% to 77% k 17% for a fixed surface irradiation as the depth of the most superficial arterial media decreased from 600 to 330 pm ( r = .94). Conclusions. Thermal injury to the arterial wall is a potent stimulus for SMC proliferation and may necessitate reduction in laser or thermal energy used for angioplasty. Moreover, a dose-response relation exists between the degree of thermal injury and SMC proliferative response. Hence, this technique could be used as a practical model of restenosis suitable for screening therapies for inhibition of SMC proliferation. AUTHORS' ABSTRACT

Thrombolysis

Hypercoagulable States in Arterial Thromboembolism. James D. Eason, Joseph L. Mills, William C. Beckett. Surg Gynecol Obstet 1992; 174:211-215. (From the Vascular Surgery Section, Wilford Hall USAF Medical Center, Lackland AFB, Texas)

Hypercoagulable states are disorders of blood coagulation, which include deficiencies of natural anticoagulants, disorders of the fibrinolytic system, presence of antiphospho- lipid antibody and abnormalities of platelet function. These disorders are well-known causes of venous thromboembolic disease and are being recognized in association with arterial thromboembolic occurrences with increasing frequency. The performance of standard prosthetic vascular reconstructions may result in disastrous outcomes in pa-

324 Journal of Vascular and Interventional Radiology March-April 1993

tients with unrecognized and untreated hypercoagulable states. From 1986 to 1990, the authors identified 12 patients with hypercoagulable states, six of whom presented with evidence of arterial thromboembolism. All of the patients were men who smoked and were somewhat younger than the usual patient with atherosclerosis. Their ages ranged from 41 to 62 years. Four patients presented with ischemic rest pain, one patient with blue toe syndrome, and one with rapidly progressive claudication. Four patients had undergone prior vascular reconstruction and two had previous pulmonary emboli. Evaluation of these patients to identify hypercoagulability included determina- tions of prothrombin time and partial thromboplastin time, platelet count, anti- thrombin 111, protein C, free protein S, and total protein S levels, along with platelet ag- gregometry. Two patients had protein S deficiency, one had protein C deficiency, one patient had protein C and S deficiency and two patients had hyperaggregable platelets. Four patients had prosthetic reconstructions and two had autogenous reconstructions. Three of the four patients undergoing prosthetic reconstructions had subsequent loss of limb and one patient died. Only one patient with prosthetic reconstruction had a patent graft on long term anticoagulation. Both patients undergoing autogenous procedures had successful revascularization with limb salvage. AUTHORS' ABSTRACT

Endogenous Fibrinolytic System in Chronic Large-Vessel Thromboem- bolic ~ulmonary Hypertension. Mitchell A. Olman, James J. Marsh, Irene M. Lang, e t al. Circulation 1992; 86: 1241-1248. (M.A.O., Committee on Vas- cular Biology, Scripps Research Institute, CVB-3, 10666 N Torrey Pines Rd, La Jolla, CA 92037)

Background. Chronic thromboembolic pulmonary hypertension (CTEPH) is a dis- order characterized by pulmonary arterial hypertension as a consequence of organized thrombotic material in the central pulmonary arteries. Incomplete resolution of acute pulmonary emboli is believed to be patho- genitally important; however, the mechanism for poor thrombus dissolution remains to be explained. The authors undertook this study to assess the major determinants of plasma fibrinolysis in patients with CTEPH (n = 32). Methods and Results. Immunolog- ical and functional levels of tissue-type plasminogen activator (t-PA) and type 1 plasminogen activator inhibitor (PAI-1) were

quantified in platelet-poor plasma (PPP) from patients with CTEPH as well as age- matched controls. Although basal PPP t-PA antigen levels (CTEPH mean, 29.5 ng/mL; control mean, 2.7 nglmL) and PAI-1 antigen levels (CTEPH mean, 55.8 ng/mL; control mean, 21.0 ng/mL) were higher in the CTEPH group, no between-group differences were detected in the enzymatic activities of these two molecules. The CTEPH group demonstrated a greater rise in t-PA antigen (CTEPH mean rise, 53.0 ngimL; control mean rise, 5.6 nglmL) and PA activity (CTEPH mean rise, 10.5 IUImL; control mean rise, 1.2 IUlmL) than controls in response to an experimentally induced venous occlusion. Immunoprecipitation and fibrin autography of PPP from two patients with markedly elevated basal t-PA antigen levels demonstrate that the t-PA antigen was present in PPP primarily in complex with PAI-1. Conclusions. Although abnormalities of the fibrinolytic system were detected, nei- ther a high resting plasma PAI-1 activity nor a blunted response of t-PA to venous occlusion can be invoked as an etiology for CTEPH. AUTHORS' ABSTRACT

Efficacy of Adjunctive Intrathrombic Heparin with Pulse Spray Thrombol- ysis in Rabbit Inferior Vena Cava Thrombosis. Karim Valji, Joseph J. Bookstein. Invest Radio1 1992; 27:912- 917. (K.V., Department of Radiology, 8756, UCSD Medical Center, 225 Dickin- son St, San Diego, CA 92103)

Rationale and Objectives. The efficacy and speed of pharmacomechanical thrombolysis may be limited by thrombotic effects of activated platelets and thrombin within the lysing clot. The authors designed an animal model of subacute venous thrombosis which was used to evaluate the effect of intrathrombic versus intravenous heparin during thrombolysis. Methods. Inferior vena cava (IVC) thrombosis was induced in rabbits by balloon catheter injury and placement of steel coils. Vena cavograms were obtained 48 hours later to document clot formation and for angiographic estimation of clot volume. Pulse-spray thrombolysis was performed by forceful injections of various agents through a catheter with multiple side holes spanning the clot. Most animals were given aspirin (30 mg orally) before treatment. After 1 hour of therapy, repeat vena cavography was performed. Animals were killed, and residual clot weight was determined. Results. Occlu- sive IVC thrombi were present in 94% of rabbits a t 2 days. Mean residual clot weight

per milliliter of estimated initial clot volume for the various treatment groups was as fol- lows: saline (n = 5) 632 mg/mL ? 54; 3 mg of tissue-type plasminogen activator (t-PA) (n = 6), 443 mg/mL ? 162; 3 mg of t-PA plus 750 U of intravenous heparin (n = 71, 408 mg/mL + 128; 3 mg of t-PA plus 500 U of intrathrombic heparin and 250 U of intravenous heparin (n = €0,213 mglmL 2 166. Differences among these groups (except t-PA alone vs t-PA plus intravenous heparin) were significant. The extent of lysis with intrathrombic plus intravenous heparin was not significantly retarded by withholding aspirin (n = 6, 194 mg/mL 2 72) or improved by giving half the intrathrombic heparin before t-PA injections (n = 6,280 mgl mL ? 158). Conclusions. The results demonstrate the advantage of adjunctive intrathrombic ~ l u s intravenous h e ~ a r i n over intravenous heparin alone in increasing the extent of pulse-spray thrombolysis in this IVC thrombosis model. AUTHORS' ABSTRACT

Embolization

Varicocele Treatment: Prospective Randomized Trial of Three Methods. Joel Sayfan, Yigal Soffer, Ruben Orda. J Urol 1992; 148:1447-1449. (J.S., Depart- ment of Surgery "A," Assaf Harofeh Med- ical Center, Zerifin 70300, Israel)

This study was done to evaluate the surgical results and the impact on fertility potential of three methods of varicocele treatment. Consecutive varicocele patients with primary or secondary infertility were randomly assigned to three treatment groups. Of the patients 36 underwent percutaneous embolization, 55 high ligation of the internal spermatic vein, and 28 transinguinal simul- taneous ligation of the internal and external spermatic veins. The transinguinal ligation proved to be safe. There was no difference in pregnancy rates but the seminal variables showed a slight improvement with statistical significance only in the two open surgical methods. There were no surgical failures in the transinguinal group as opposed to the other two techniques. Transinguinal ligation of the internal and external spermatic veins may be recommended as the primary treatment for varicocele. This technique also seems to be the procedure of choice when repeat intervention is required for failure of high ligation or embolization. AUTHORS' ABSTRACT

Abstracts 325

Volume 4 Number 2

Reflux of Ethanol during Experimen- tal Liver Ethanol Injections. Tapio Vehmas. Invest Radiol 1992; 27:918-921. (T.V., Department of Radiology, Helsinki University, Haartmaninkatu, SF-00290 Helsinki, Finland)

Rationale and Objectives. The reflux of ethanol into the peritoneal cavity during percutaneous ethanol injection therapy (PEIT) of liver neoplasms may cause pain and other side effects. This article studies the optimal injection technique to minimize the reflux of ethanol. Methods. A technique using normal postmortem pig livers was developed to measure the amount of reflux in different experimental injection situations. Results. The proportional reflux increased significantly when the needle diameter (0.55-1.1 mm) was larger (P < .01) and when the injection was more superficial (P < .0005) (ie, the needle traversed a shorter distance [I-5 cml inside the liver tissue). Speeding up the injection (0.13-1.5 glsec) produced suggestive (P < ,101 increase of the proportional reflux. The proportional reflux was not affected by either the ethanol dose (0.40-2.06 g) or the time lapse (0-30 seconds) after the injection when the needle was left in situ before its withdrawal. Conclusions. The reflux of ethanol during percutaneous ethanol injection therapy is influenced by the diameter of the needle and by the technique used. Further studies are needed to fully clarify the clinical validity of these results. AUTHOR'S ABSTRACT

The Current Status of Embolization in Renal Cell Carcinoma: A Survey of Local and National Practice. D. Lanigan, E. Jurriaans, J. C. Hammonds, e t al. Clinical Radiology 1992; 46:176- 178. (D.L., Department of Urology, Derri- ford Hospital, Plymouth PL6 8DH, En- gland)

The current role of renal embolization in carcinoma of the kidney is uncertain. In order to assess surgeons' opinion of its useful- ness a questionnaire was circulated to all general urologists practising in Britain and Ireland. Also, a series of cases in which the technique was employed (n = 35) was reviewed and compared with a similar group who were not embolized (n = 40). There was a 71% response to the survey. The principal findings were that all but five urologists be-

lieve that embolization should not be used routinely in the management of renal cell carcinoma. Thirty-five% stated that they felt it has a role in management of symptoms in metastatic or inoperable turnours. The review of both series of patients in the authors' unit shows that embolization (using 95% ethanol infused via a balloon occlusion catheter) did not reduce peroperative blood loss and did significantly increase hospital stay. There were no deaths in this series, and morbidity was confined to "post-embolization syndrome" in 16 cases. The authors believe that in those cases where embolization is indicated, alcohol infusion via a balloon occlusion catheter is a safe and efficient method. AUTHORS' ABSTRACT

Embolization with Detachable Bal- loons: Applications Outside the Head. N. M. DeSouza, J. F. Reidy. Clin Radiol 1992; 46:170-175. (N.M.D., De- partment of Radiology, Guy's Hospital, S t Thomas' St, London SElgRT, England)

Detachable balloons, although widely used as an embolization material in neuro- vascular work, are rarely used outside the head. Yet they offer distinct advantages over other methods of embolization in certain situations. They can effect an instant and precise occlusion of large arteries and fistulae and unlike any other embolization technique the occlusion is reversible until the balloon is finally detached. In addition, they can be floated out to distal locations inacces- sible with more conventional catheter techniques. They are inflated with contrast medium or silicone monomers. Large arteries and arteriovenous fistulae (AVFs) are best suited to balloon embolization where embolization distal to the fistula resulting in pa- renchymal infarction is not indicated. Thir- teen patients underwent 14 detachable balloon embolizations. Eleven had large AVFs (four coronary AVFs, four Blalock- Taussig shunts, two vertebrovertebral fistulae, and one renal AVF) and three had large arteries (two aortopulmonary collaterals in one patient and one innominate artery pseudoaneurysm). Twelve of these embolization procedures were successful, and there were no complications. The two failures were due to inability to pass the balloon catheter around an acute angle in the intro- ducer catheter and to early deflation. These cases illustrate a wide range of situations where balloon embolization may be used successfully. Continued refinement and im-

provement in the technique will allow expansion of the indications for nonneurologi- cal balloon embolization. AUTHORS' ABSTRACT

W Cardiac

Transcatheter Occlusion of Persis- tent Arterial Duct. Report of the Eu- ropean Registry. Lancet 1992; 340: 1062-1066. (M. Tynan, Department of Paediatric Cardiology, Guy's Hospital, London SElgRT, England)

Rashkind's "double umbrella" technique for percutaneous transcatheter occlusion of patent arterial duct (ductus arterio- SUS) has been used successfully in several centres. To assess its feasibility, safety, and efficacy in routine clinical practice, a Euro- pean registry was established. In 642 of 686 patients entered into the study, the device was successfully implanted at the first attempt, and in a further nine at a subsequent attempt. Four hundred ninety-one patients (71% of all patients entered) had Doppler- echocardiographic evidence of complete occlusion with a single device at the latest follow-up. Kaplan-Meier survival estimates indicated a complete occlusion rate of 82.5% (95% confidence interval, 79.4%-85.8%) at 1 year after implantation of a single device. A second device was implanted in 41 patients with residual flow, and 37 of these had complete occlusion, giving an overall latest follow-up occlusion rate of 77% and an actuar- ial complete occlusion rate for one or two devices of 94.8% (95% CI, 92.9%-96.7%) at 30 months after implantation of the first device. Two early deaths occurred (0.3%), both in patients with associated ventricular septa1 defect. Complications included embo- lisation of the device in 18 patients (2.6%), of whom six underwent catheter-retrieval of the device. Mechanical haemolysis occurred in a further four patients (0.6%). Transcath- eter occlusion of the arterial duct is a safe and effective alternative to surgical closure. A second device is sometimes needed to achieve complete occlusion. AUTHORS' ABSTRACT


March-April 1993

I GASTROINTESTINAL

Obscure Bleeding in the Gastrointes- tinal Tract Originating in the Small Intestine. W. Y. Lau, W. K. Yuen, K. W. Chu, e t al. Surg Gynecol Obstet 1992; 174:119-124. (A. K. C. Li, Department of Surgery, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong)

In the past 12 years, the authors oper- ated upon 49 patients with bleeding lesions of the small intestine. After endoscopic examination and barium studies of the upper and lower gastrointestinal tract excluded esophagogastroduodenal and lesions of the colon and rectum, preoperative examina- tions consisted of technetium-99m pertech- netate scanning, Tc-99m-labeled erythro- cyte scanning, barium studies of the small intestine, and selective visceral angiography. In one patient, diagnostic laparotomy had to be done before any procedure because of severe bleeding and angiosarcoma of the il- eum. The results of gross examination at operation revealed bleeding lesions in 40 patients. Special intraoperative localization procedures consisting of methylene blue injection through superselectively preposi- tioned angiographic catheter were done in eight patients, and intraoperative enteros- copy was done in 17 patients. These two procedures were complementary, having their own indications and limitations. This regimen of preoperative and intraoperative localization procedures was effective in the management of bleeding small intestinal lesions. AUTHORS' ABSTRACT

Clinical Features and Endoscopic Management of Dieulafoy's Disease. Mark E. Stark, Christopher J. Gostout, Rita K. Balm. Gastrointest Endosc 1992; 38:545-550. (C.J.G., Division of Gastro- enterology, Mayo Clinic, 200 First S t SW, Rochester, MN 55905)

The experience of a specialized management team using urgent endoscopy in the management of acute gastrointestinal bleeding from Dieulafoy's disease is presented. Dieulafoy's disease was found in 19 of 1,124 consecutive patients with upper gastrointestinal bleeding. Most patients with Dieula- foy's disease were elderly men with severe acute upper gastrointestinal hemorrhage. Endoscopic diagnosis was possible in all patients but required multiple endoscopies in 378. The lesions were in the proximal stom-

ach (79%) and duodenal bulb (21%). Endo- scopic therapy included epinephrine injection, then heater probe coagulation in 17 patients, bipolar electrocoagulation in one, and neodymium yttrium aluminum garnet laser photocoagulation in one. Endoscopic therapy was successful in 18 patients (95%); one patient had successful surgery after endoscopic therapy failed. There were no deaths due to bleeding and no endoscopic complications. Dieulafoy's disease is an un- usual cause of acute gastrointestinal bleeding. Endoscopic diagnosis is sometimes diffi- cult, but primary endoscopic therapy is safe, successful, and should be attempted. AUTHORS' ABSTRACT

Long Term Results of Percutaneous Catheter Drainage of Pancreatic Pseudocysts. Enrique Criado, Amy A. De Stefano, Timothy M. Weiner, e t al. Surg Gynecol Obstet 1992; 175:293-298. (E.C., Department of Surgery, 210 Bur- nett-Womack Bldg, CB No. 7210, Chapel Hill, NC 27599-7210)

Percutaneous catheter drainage (PCD) has become an established and often preferred alternative to surgical treatment in the management of pancreatic pseudocysts. However, the long-term results of percutaneous drainage of pancreatic pseudocysts remain uncertain. In an effort to determine the long-term outcome of this therapy, 42 patients undergoing PCD of a pancreatic pseudocyst were analyzed retrospectively. Forty-two pancreatic pseudocysts were drained percutaneously in 42 patients. Six- ty-seven percutaneous drainage procedures were performed-22 patients underwent one, 15 had two, and five patients required three procedures. Percutaneous drainage was considered not to be effective when the pseudocyst persisted or when it recurred after initial resolution. Twenty-three pseudocysts were infected at the time of drainage, and 19 were not infected. In 30 patients, the cause of the pseudocyst was alcoholic pancreatitis. There were no deaths related to the procedures and seven complications occurred, including hemorrhage, pancreatic fistula, and empyema. Mean follow-up evaluation time of the patients was 10 months. In nine patients, the pseudocyst was successfully drained and resolved. There were 33 treatment failures, among which 26 pseudocysts failed to resolve and seven recurred after initial resolution. Eventually, 25 patients underwent a surgical procedure, 20 for persistent pseudocyst and five for recurrence. Using contingency table analysis, the size of the pseudocyst, amount of fluid

drained, amylase concentration in the aspi- rate, presence of infection, number of drainage procedures performed and duration of catheter drainage had no influence on the likelihood of success in long term pseudocyst resolution after PCD. Pseudocysts not related to alcoholic pancreatitis seemed to be less likely ( P < .05) to resolve with percutaneous drainage than those caused by alcohol. PCD is a safe and valuable procedure in the acute management of patients with pancreatic pseudocyst. However, the current data suggest that despite early success with percutaneous drainage, the lack of resolution and recurrence rate of pancreatic pseudocyst is high. Therefore, it should not be considered as the definitive form of therapy in most patients. Close surveillance of patients undergoing percutaneous drainage and communication between surgeons and radiologists are critical in the management of pancreatic pseudocysts. AUTHORS' ABSTRACT

Failure of Percutaneous Drainage of Pancreatic Abscesses Complicating Severe Acute Pancreatitis. Nelly Rot- man, Didier Mathieu, Marie-Christine Anglade, e t al. Surg Gynecol Obstet 1992; 174:141-144. (N.R., Service de Chirurgie digestive, Hbpital Henri Mondor, 51 ave du Marechal de Lattre de Tassigny 94010, Creteil, France)

From 1981 to 1990, 14 of 70 patients hospitalized at the authors' institution for severe acute pancreatitis were selected to undergo percutaneous drainage of pancreatic abscess, under computed tomographic (CT) guidance. Pancreatic abscess was defined, on contrast-enhanced CT scan, as an infected fluid collection without pancreatic necrosis. There were nine men and five women, ranging in age from 28 to 46 years. The main cause of pancreatitis was alcohol abuse (eight patients). Other causes were gallstones (two patients), hyperlipidemia (two patients), postoperative condition (one patient), and one unknown. Ranson criteria were available in 10 patients and ranged from three to six. Percutaneous drainage was performed as the primary treatment in 13 patients and for removal of a residual collection postoperatively in one patient. In two critically ill patients, percutaneous drainage was performed as a temporizing measure. In 12 patients with well-limited hypodense collections, percutaneous drainage was ex- pected to result in the definitive cure of the abscess. Pigtail drains (No. 14 F), were in-

Abstracts 327

Volume 4 Number 2

serted with use of local anesthesia and CT guidance. Two patients had two drains, and 12 patients had only one drain. Two patients were definitively cured by percutaneous drainage, and all other patients were oper- ated upon for removal of infected necrosis. In this study, the lack of accuracy of contrast-enhanced CT in the diagnosis of peripancreatic necrosis is highlighted, and the fact that percutaneous drainage has a better efficiency in the treatment of residual collections postoperatively than as a primary treatment of infected fluid collections is il- lustrated. AUTHORS' ABSTRACT

Treatment of Peripancreatic Fluid Collections in Patients with Compli- cated Acute Pancreatitis. Barry W. Feig, Richard A. Pomerantz, Robert Vog- elzang, e t al. Surg Gynecol Obstet 1992; 175:429436. (Raymond J . Joehl, Surgi- cal Service [112], Veterans ARairs Lake- side Medical Center, 333 E. Huron, Chi- cago, IL 60611)

The authors reviewed an experience with treatment of peripancreatic fluid collections in patients with complicated acute pancreatitis to identify clinical and computed tomographic (CT) parameters that are helpful in the selection of patients for treatment and to assess treatment outcome. The extent of CT abnormalities determined a CT severity score (mild = 1, severe = 4). From 1985 to 1990, 650 patients were hospitalized with acute pancreatitis; a peripancreatic fluid collection was found in 36 patients (5.5%). Ten of 11 patients with successful outcome after no invasive treatment (group 1) had a low CT severity score of 1 or 2; the mean serum albumin level was 4.0 g1dL. Of 25 patients who had some form of drainage, 12 had a high CT severity score of 3 or 4 (P < .05) and a mean serum albumin ave of 3.4 g1dL (P < ,051. Nine patients had only operative drainage (group 2), and 16 had CT-directed percutaneous catheter drainage (group 3). In group 3, percutaneous catheter drainage successfully drained the fluid collection in six patients, while 10 patients needed an operation, in addition to percutaneous drainage, to effectively debride and drain the necrotizing pancreatic problem. As a result of the current review, the authors propose an algorithm for treatment of these patients. AUTHORS' ABSTRACT

Advances in Enteral Nutrition Tech- niques. William N. Baskin. Am J Gastro- enter01 1992; 87:1547-1553. (W.N.B., Rockford Gastroenterology Center, Ltd, 401 Roxbury Rd, Rockford, IL 61107)

The increasing use of enteral nutrition in hoswitals has led to an ex~anded role for the gastroenterologist and surgeon in pro- viding enteral access. New conce~ts in im- - munonutrition and gut support in critically ill patients have popularized early postoperative feeding. There is an ongoing need to update physicians on the diverse enteral access techniques now available. In addition to standard percutaneous endoscopic gastros- tomy and percutaneous endoscopic jejunos- tomy (PEJ) techniques, this review focuses on reflux prevention through double-lumen feeding-suction tubes and describes the use of steerable catheters for rapid insertion of nasojejunal and PEJ tubes without endoscopy. Low-profile "buttonn-type devices, one-step button placement, replacement gas- trostomy devices, and special enteral techniques for patients with cancer are also reviewed. AUTHOR'S ABSTRACT

I HEPATOBILIARY

Hepatic Arterial Infusion of Floxuri- dine in Patients with Liver Metasta- ses from Colorectal Carcinoma: Long-term Results of a Prospective Randomized Trial. Philippe Rougier, Agnes Laplanche, Michel Huguier, e t al. Clin Oncol 1992; 10:1112-1118. (P.R., Institut Gustave-Roussy, 94805 Villejuif, France)

Purpose: A multicentric randomized study was performed that compared patients who received intrahepatic arterial infusion (HA11 for unresectable hepatic metastases from primary colorectal carcinoma to patients who did not receive HA1 (control group). Patients and Methods: One hundred sixty-six patients were assigned randomly to HA1 of floxuridine (5 fluoro-2'deoxyuridine IFUDRI) (0.3 mglkgid for 14 days every 4 weeks) or to the control group; this latter group, depending on the investigator's choice, was either under observation or received systemic fluorouracil(5-FU). The same regimen of systemic 5-FU also was administered to the HA1 group in the event of extrahepatic progression. No crossover from the control group to the HA1 group was per-

mitted. The mean duration of follow-up was 54 months (range, 31-72 months), and 163 patients were analyzed. Results: A significant improvement was observed in the survival rate for the 81 patients assigned to the HA1 group (P < .02) with a 1-year survival rate of 64% versus 44% in the control group (82 patients). The 2-year survival rate was 23% versus 13%. The median survival was 15 months versus 11 months for the HA1 group and the control group, respectively. Survival was better for patients with a less than 30% liver involvement and for those treated in more specialized centers. The hep- atotoxic effects of HA1 were observed in 47 patients (chemical hepatitis [n = 281 and biliary sclerosis In = 191). The 1-year rate of sclerosing cholangitis was equal to 25%. Gastrointestinal toxicity was infrequent and consisted of gastritis or diarrhea. Conclu- sions: Therapy with HA1 of FUDR improves the survival of patients with liver metastases over colorectal carcinoma. However, the methods that are used to diminish the toxicity of HA1 and efficient systemic chemother- apy, such as a combination of 5-FU and leu- covorin, are required to prevent extrahepatic metastases. AUTHORS' ABSTRACT

Percutaneous Ethanol Injection under Sonographic Guidance of Hepa- tocellular Carcinoma in Compen- sated and Decompensated Cirrhotic Patients. Antonio Giorgio, Luciano Tar- antino, Giampiero Francica, e t al. J Ul- trasound Med 1992; 11:587-595. (A.G., Viale Colli Aminei 491, 80131 Naples, It- aly)

Forty-six patients with cirrhosis and 75 biopsy-proved hepatocellular carcinoma (HCC) nodules underwent percutaneous ethanol injection (PEI) regardless of number (up to five) and size (mean diameter, 3.6 cm) of tumoral lesions and clinical severity of cirrhosis (11 patients in Child's class C were included). Ethanol was injected under sonographic guidance through 20-22-gauge needles so as to obtain homogeneous hyperecho- genicity of lesions. A total of 271 PEI sessions were carried out, delivering 2-14 mL per session. All nodules but one decreased in size, and seven were no longer appreciable on sonography. Recurrence was detected in two patients. The 3-year survival rate of all cases was 86%. Child's classes A and B patients fared better (3-year survival 100%); the 2-year survival of subjects with HCC no larger than 3 cm was 92%. Multifo- cality did not affect survival. Most patients experienced mild pain at the site of injection,

328 . Journal of Vascular and Interventional Radiology

March-April 1993

but only two major complications were en- countered: partial chemical thrombosis of the left portal vein and cholangitis. Both cases were managed conservatively. In conclusion, PEI seems to offer a safe and valuable tool for therapy of HCC, especially in patients with good functional liver reserve and small ( 5 3-cm) tumors. AUTHORS' ABSTRACT

Critical Review of the Treatment of Pyogenic Hepatic Abscess. John H. Robert, Dan Mirescu, Patrick Ambrosetti, e t al. Surg Gynecol Obstet 1992; 174:97- 102. (J.H.R., Clinique de Chirurgie Diges- tive, HBpital Cantonal Universitaire, CH- 1211 Geneva, Switzerland)

A retrospective review of 29 consecutive patients with pyogenic hepatic abscesses was undertaken to ascertain the efficacy of various treatments. Percutaneous routes were used 25 times (aspiration alone in 16 and with concomitant drainage in nine), as a primary step 22 times and for recurrent abscesses three times. An operation was required in nine patients; initially in five and after percutaneous treatment in four. Anti- biotics alone were used twice. There were seven deaths, two after antibiotics alone and five after initial percutaneous aspirations. There were six recurrent abscesses, all but one after percutaneous aspiration. These results suggest that antibiotics alone and percutaneous aspiration alone are inade- quate in the treatment of pyogenic hepatic abscesses, that percutaneous management is valid provided concomitant drainage is used, and that once the abscess has been successfully handled percutaneously, surgical treatment is a safe alternative as a first step, for abscesses recurring after percutaneous management or for removal of the primary cause of the disease. AUTHORS' ABSTRACT

A Multicenter, Randomized, Con- trolled Trial to Evaluate the Effect of Prophylactic Octreotide on ERCP- induced Pancreatitis. Jonathan M. Sternlieb, Craig A. Aronchick, Jeffrey N. Retig, e t al. Am J Gastroenterol 1992; 87: 1561-1566. (C.A.A., Pennsylvania Hospi- tal, Eighth and Spruce Sts, Philadelphia, PA 19107)

Eight-four patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) were randomized to receive 100 kg of octreotide intravenously immediately prior to ERCP and 100 kg subcutaneously 45 minutes after the initial dose, or placebo. Amylase, lipase, and glucose levels were

measured and clinical assessment was performed before, and 2 and 24 hours after, ERCP. The authors define clinical pancreatitis as the combination of elevated amylase or lipase levels with abdominal pain and ten- derness. Interim analysis in 84 patients revealed an 11% incidence of clinical pancreatitis in the control group and 35% in the treatment group (P < .01). There were no differences in either group with respect to sphincterotomy, gender, age, duration of ERCP, number of cannulations of the pancreatic duct, degree of duct injection, or the volume of contrast material injected. An analysis of group differences stratified by sphincterotomy was performed In patients who did not undergo a sphincterotomy, there was a significantly higher rate of pancreatitis in the treatment group (10 of 17 [59%1 vs one of 17 [6%1; relative rut, 10.0 195% confidence interval, 1.4-69.81). Sphinc- terotomy reduced the rate of pancreatitis in patients who received octreotide from 10 of 17 (59%) to three of 20 (15%) (P = .01), which equals the rate in patients who received placebo and underwent sphincterotomy (four of 25 [16%1). Although the incidence of pancreatitis was higher in the treatment group, octreotide may reduce the severity of pancreatitis measured by the number of days NPO (Wilcoxon rank sum, P = .02), length of stay after ERCP (P = ,131, the number of days of pain (P = .11), and the degree of amylase eleva- tion (P = .04). The authors conclude that (a) Octreotide appears to increase the incidence of pancreatitis when given prophylac- tically for diagnostic ERCP; (b) although pancreatitis was more common in the octreotide group, it was less severe than in the placebo group; (c) sphincterotomy may af- ford protection against pancreatitis in patients who received octreotide; and (d) they cannot recommend the use of prophylactic octreotide during diagnostic or therapeutic ERCP. AUTHORS' ABSTRACT

A New Method for Thermocholecys- tectomy: Initial Experience and Comparison with Other Techniques. John P. McGahan, John M. Brock, Ste- phen M. Griffey, e t al. Invest Radio1 1992; 27:947-953. (J.P.M., University of Cali- fornia Davis Medical Center, Division of Diagnostic Radiology [Research], 2516 Stockton Blvd, TICON 11, Sacramento, CA 95817)

Rationale and Objectives. The authors tested the feasibility of thermocholecystec- tomy for gallbladder ablation in an animal

model. Methods. Thermal treatment of the cystic duct followed by heating of the saline- filled gallbladder using a separately designed heaterlexpander was performed in 13 pigs (group 1). In four animals, heating of the gallbladder alone was performed (group 2). Two animals served as controls (group 3). All animals were killed 12 weeks after treatment. Results. There was cystic duct occlusion in 10 (77%) of 13 of group 1 animals. In six (60%) of 10 of these animals with cystic duct occlusion, there was complete ablation of the gallbladder mucosa and complete obliteration of the gallbladder lumen. In group 2 animals, all cystic ducts were intact with an unchanged gallbladder volume in all four animals (loo%), and normal gallbladder mucosa were intact in three (75%) of four animals. The gallbladders and cystic ducts in group 3 animals were normal. Conclu- sions. This study demonstrates many technical difficulties with thermal cholecystectomy. However, under ideal conditions, permanent gallbladder ablation is feasible in this animal model using a specially designed heating system. AUTHORS' ABSTRACT

I GENITOURINARY

Review: Anatomic Background for Intrarenal Endourologic Surgery. Francisco J. B. Sampaio. J Endourol 1992; 6:301-304. (F.J.B.S., Caixa Postal No. 46503, 20562 Rio de Janeiro, Brazil)

A serious and troublesome complication of endoscopic intrarenal operation is bleeding from an injured vessel. To diminish the risk of such injury, the operator must know and recall the spatial position of the intrarenal vascular structures and their anatomic relations with the collecting system. The analysis of 82 three-dimensional endocasts of the kidney collecting system together with the intrarenal arteries and 52 endocasts of the collecting system with the veins showed that the segmental and the interlobar branches of the renal artery as well as the major intrarenal tributaries of the renal vein are in close relation with the anterior and posterior surfaces of the major caliceal in- fundibula as well as of the necks of the mi- nor calices. Considering that the circumfer- ence of an infundibulum is composed of four quadrants, the infundibular incision must be done in the superior or inferior quadrant, because in general, these areas are free of

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Volume 4 Number 2

large vessels. Contrariwise, the posterior and, mainly, the anterior quadrants are often in contact with major vessels. From an anatomic standpoint, if more than one infundibular incision is necessary, the authors recommend the following sequence: the first incision in the superior quadrant, the second in the inferior quadrant, the third between the superior and posterior quadrants, the fourth between the inferior and posterior quadrants, and the fifth in the posterior quadrant. Anterior incisions must be always avoided. AUTHORS' ABSTRACT

Anatomic, Functional, and Patho- logic Changes from Internal Ure- teral Stent Placement. Daniel J . Culkin, Roger Zitman, W. Stewart Bun- drick, et al. Urology 1992; 40:385-390. (D.J.C., Department of Urology, Louisi- ana State University Medical Center, PO Box 33932, Shreveport, LA 71130-3932)

The anatomic, hydrodynamic, functional, and pathologic changes associated with unilateral internal ureteral stenting were evaluated in 20 female canines. Selec- tive glomerular filtration rates (GFR) were measured with technetium-99m diethylene- triamine pentaacetic acid (DTPA) renal scanning (n = 14) prior to and several weeks after unilateral internal stent placement. Cystometry and cystography were done at weekly intervals to determine if reflux occurred and to measure the intravesical pressure to produce this reflux (n = 16). Ure- teral luminal capacities of mid 6-cm ureteral segments of stented and unstented ureters were compared. The midureteral luminal volumes were three times greater in the stented ureters (P < .002). There were no significant differences in the selective GFR before and after stenting. Low-pressure vesicoureteral reflux occurred at a mean intravesical pressure of 13.7 cm Hz0 and was present in 84.6% (11 of 13) of the canines whose stents did not migrate or obstruct from encrustation. There were no significant alterations in serum chemistries or blood counts. Fluoroscopic imaging also showed ineffective ureteral peristalsis. This study confirms that internal ureteral stents cause vesicoureteral reflux and significant luminal dilation without altering renal function. AUTHORS' ABSTRACT

Microbial Adhesion and Biofilm For- mation on Ureteral Stents In Vitro and In Vivo. Gregor Reid, John D. Den- stedt, Yun Suk Kang, e t al. J Urol 1992; 148:1592-1594. (G.R. Office of Research Services, SLB 328, University of Western Ontario, London, Ontario, Canada N6A 5B8)

Thirty ureteral stents, inserted for 5-128 days following extracorporeal shock wave lithotripsy, were examined for the presence of bacterial biofilms. Of these, 90% had adherent pathogens (44% mixed organisms) on the stents, 45% of which were present in low numbers (10'-lo2 per 1-cm3 section) and 55% were in small and large microcolony biofilms (> 2 x lo2-lo7). The organisms were recovered from the stents even though urine culture was only positive in 27% of patients. Of the organisms isolated, 77% were gram-positive cocci, 15% gram-negative rods, and 8% Candida. No blockage of the stents occurred. All of the patients had received antimicrobial therapy after insertion, and in 15 cases biofilms were found while on treatment. None of the patients received therapy for urinary tract infections while the stent remained in place. In vitro experiments demonstrated the abil- ity of Escherichia coli, Proteus mirabilis, Staphylococcus epidermidis, and Enterococ- cus faecalis uropathogens to adhere and form biofilms on ureteral stents within 24 hours. Clearly, bacterial biofilms do occur on ureteral stents and urinary culture may not detect their presence. The high recovery rate of gram-positive organisms may indicate a preferential adhesion to the biomaterial surface. The findings also indicate that unlike biofilm formation on many other prosthetic implants, colonization with gram-positive organisms on ureteral stents does not neces- sarily coincide with the development symptomatic infection. AUTHORS' ABSTRACT

I NEUROINTERVENTIONAL

Posttraumatic Cerebral Arterial Spasm: Transcranial Doppler Ultra- sound, Cerebral Blood Flow, and An- giographic Findings. Neil A. Martin, Curtis Doberstein, Cynthia Zane, e t al. J Neurosurg 1992; 77:575-583. (N.A.M., Division of Neurosurgery, University of California a t Los Angeles School of Medi- cine, 74-140 CHS, 10833 Le Conte Ave, Los Angeles, CA 90024)

Thirty patients admitted after suffering closed head injuries, with Glasgow Coma Scale scores ranging from 3 to 15, were evaluated with transcranial Doppler ultrasound monitoring. Blood flow velocity was determined in the middle cerebral artery (MCA) and the intracranial portion of the internal carotid artery (ICA) in all patients. Because proximal flow in the extracranial ICA de- clines in velocity when arterial narrowing becomes hemodynamically significant, the extracranial ICA velocity was concurrently monitored in 19 patients. To assess cerebral perfusion, cerebral blood flow (CBF) measurements obtained with the intravenous Xe-133 technique were completed in 16 patients. Vasospasm, designated as MCA velocity exceeding 120 cmlsec, was found in eight patients (26.7%). Severe vasospasm, defined as MCA velocity greater than 200 cmlsec, occurred in three patients and was confirmed by angiography in all three. Suh- arachnoid hemorrhage (SAH) was docu- mented by computed tomography in five (62.5%) of the eight patients with vasospasm. All cases of severe vasospasm were associated with subarachnoid blood. The time course of vasospasm in patients with traumatic SAH was similar to that found in patients with aneurysmal SAH; in contrast, arterial spasm not associated with SAH demonstrated an uncharacteristically short duration (mean 1.25 days), suggesting that this may be a different type of spasm. A significant correlation (P < .05) was identified between the lowest CBF and highest MCA velocity in patients during the period of vasospasm, indicating that arterial narrowing can lead to impaired CBF. Ischemic brain damage was found in one patient who had evidence of cerebral infarction in the territories supplied by the arteries affected by spasm. These findings demonstrate that de- layed cerebral arterial spasm is a frequent complication of closed head injury and that the severity of spasm is, in some cases, com- parable to that seen in aneurysmal SAH.


March-April 1993

This experience suggests that vasospasm is an important secondary posttraumatic in- sult that is potentially treatable. AUTHORS' ABSTRACT

Endovascular Treatment of Poste- rior Circulation Aneurysms by Elec- trothrombosis Using Electrically De- tachable Coils. Guido Guglielmi, Fernando Vinuela, Gary Duckwiler, e t al. J Neurosurg 1992; 77:515-524. (G.G., De~art imento di Scienze Neurolopiche. ~ e u r o a n g i o ~ r a f i a Terapeutica, Universita di Roma. Viale dell'Universita, 30la. 00185 ~ b m e , Italy)

In a multicenter study, 120 patients with intracranial aneurysms presenting a high surgical risk were treated using electro- lytically detachable coils and electrothrom- bosis via an endovascular approach. The results of treatment in patients with posterior fossa aneurysms (42 patients with 43 aneurysms) are presented. The most frequent clinical presentation was subarachnoid hemorrhage (24 cases). The clinical follow-up periods ranged from 1 week to 18 months. Complete aneurysm occlusion was obtained in 13 of 16 aneurysms with a small neck and in four of 26 wide-necked aneurysms. A 70%-98% thrombosis of the aneurysm was achieved in 22 of 26 aneurysms with a wide neck and in three of 16 small-necked aneurysms. One aneurysm could not be treated due to a technical complication. Two cases required postprocedural surgical clipping of a residual aneurysm. One patient (originally in Hunt and Hess grade V) experienced procedural rupture of the aneurysm requiring an emergency parent artery occlusion. He eventually died 5 days later. Another patient (originally in grade IV) had coil migration and posterior cerebral artery territory ischemia. A third patient developed a permanent neurological deficit (hemianopsia) after complete occlusion of a wide-necked basilar bifurcation aneurysm. One patient, harboring an inoperable giant basilar bifurcation aneurysm, died from aneurysm bleeding 18 months after partial occlusion. Overall morbidity and mortality rates related to treatment were 4.8% (two cases) and 2.4% (one case), respectively (2.6% and 0% if considering only patients in Hunt and Hess grades I, 11, and 111). It is suggested that this technique is a viable alternative in the management of patients with posterior fossa aneurysms associated with high surgical risk. Longer angiographic and clinical follow-up study is necessary to determine the long- term efficacy of this recently developed endovascular occlusion technique. Close postop-

erative angiographic and clinical monitoring of patients with wide-necked subtotally occluded aneurysms is mandatory to check for potential aneurysmal recanalization, re- growth, and rupture. AUTHORS' ABSTRACT

Intracranial Arterial Aneurysm due to Birth Trauma: Case Report. Joseph H. Piatt, J r , David A. Clunie. J Neurosurg 1992; 77:799-803. (J.H.P., Division of Neurosurgery lL4721, Oregon Health Sci- ences University, Portland, OR 97201- 3098)

The authors present what is believed to be the first description of an intracranial arterial aneurysm attributable to birth trauma. A male neonate, the product of a precipitious, instrumented, footling breech delivery, exhibited seizures at the age of 18 hours. A computed tomographic scan of the head showed hemorrhage along the tento- rium with a globular component at the incisura. Transfontanel Doppler ultrasound examination detected pulsatile arterial flow within the globular mass. Cerebral angiography demonstrated a 1.5-cm saccular aneurysm arising from a small distal branch of the superior cerebellar artery. The patho- genesis of aneurysms in children is obscure and controversial. Birth trauma may be responsible for some pediatric aneurysms that are currently classified as idiopathic or con- genital, particularly aneurysms in the region of the tentorial incisura. AUTHORS' ABSTRACT

Endovascular Treatment of Intra- cranial Dural Arteriovenous Fistulas with Spinal Perimedullary Venous Drainage. Y. Pierre Gobin, Andre Rogo- poulos, Armand Aymard, et al. J Neuro- surg 1992; 77:718-723. (Y.P.G., Service de Neuroradiologie, H8pital Lariboisiere, 2 rue Ambroise Pare, 75745 Paris, France)

Intracranial dural arteriovenous (AV) fistulas with spinal perimedullary venous drainage are rare lesions that have distinc- tive clinical, radiological, and therapeutic aspects. Five patients presented with an as- cending myelopathy, which extended to in- volve the brain stem in three cases. Myelog- raphy and magnetic resonance imaging showed slightly dilated spinal perimedullary vessels. Spinal angiograms were normal in the arterial phase. Diagnosis was only possible after cerebral angiography, which demonstrated wosterior fossa AV fistulas fed by meningeal arteries and draining into spinal perimedullary veins. Endovascular treat-

ment alone resulted in angiographic obliteration of the lesion in three patients. Two patients required surgery in addition to endovascular therapy. One patient died postoperatively, and in one a transient complication of embolization was observed. Improve- ment after treatment was good in two cases and fair in two. Transverse sinus thrombosis was observed in three cases and was probably the cause of the aberrant venous drainage of the fistula into the spinal perimedullary veins. The pathophysiology is related to spinal cord venous hypertension. These lesions were classified as type 5 in the Djindjian and Merland classification of dural intracranial AV fistulas. Endovascular therapy is a safe effective method in the treatment of these fistulas and should be tried first. AUTHORS' ABSTRACT

I TRANSPLANTATION

Interventional Endourologic Proce- dures after Renal Transplantation. K. Hobarth, J . Hofbauer, M. Marberger. J Endourol1992; 6:341-346. (K.H., De- partment of Urology, University of Vi- enna Medical School, Alser Strasse 4, A-1090 Vienna, Austria)

Interventional endourologic procedures were performed in 21 of 257 renal trans- plant recipients, representing a rate of urologic complications of 8.2%. Antegrade ~~e lography studies are the key to the diagnosis of ureteral obstruction or leakage. Ret- rograde manipulations failed in 57%, especially in the early postoperative period when the ureteroneocystostomy was found to be grossly edematous. In cases of suspected obstruction and hydronephrosis, antegrade procedures are more suitable, especially when temworarv urinarv diversion is also "

needed. In cases of ureteral compression by pararenal fluid collections, puncture and temporary percutaneous drainage usually solve the problem. Leaks at the site of the ureteroneocystostomy are successfully treated by endourologic procedures, whereas surgical intervention is indicated in cases of ureteral necrosis; however, primary differ- entiation between leakage and ureteral necrosis is not possible. A success rate of 60% in cases of leakage justifies a primary endourologic approach. Five patients (24%) required subsequent surgery, but temporary urinary diversion prior to the operation was

Abstracts 331

Volume 4 Number 2

nonetheless helpful. Sixteen patients (76%) were cured by endourologic procedures alone. Only one procedure-related complication (4.7%) was observed. Invasive percutaneous and endoscopic uroradiologic techniques for the diagnosis and treatment of urologic complications in the aftermath of renal transplantation may be considered safe. AUTHORS' ABSTRACT

CONTRAST MATERIAL

Early Effect of Gadopentate and Io- dinated Contrast Media on Rabbit Kidneys. P. Leander, M. Allard, J . M. Caille, e t al. Invest Radiol 1992; 27:922- 926. (P.L., Department of Experimental Research, University of Lund, Malmo General Hospital, S-21401 Malmo, Swe- den)

Rationale and Objectives. The authors compared the physiologic and nephrotoxic effects of the magnetic resonance imaging - - contrast medium gadopentetate with two conventional radiographic contrast media. Methods. Rabbits were injected intravenously with one of the following solutions: gadopentetate (0.1 moliL), iohexol (300 mg of iodine per milliliter), metrizoate (300 mg of iodine per milliliter), and NaCl (0.9%). Blood samples were taken before and 5, 15, 45,90, and 180 minutes after injection of the solutions and were analyzed for creatinine, aldosterone, and contrast media levels. Urine was sampled before and 1, 2.5, and 5 hours after injection of the solutions, and creatinine, leucine amino-peptidase (LAP), alkaline phosphatase (ALP), gamma glutaryl transferase (GGT), and N-acetyl p-D-glu- cosaminidase (NAG) activities were quantified. Results. Contrast media clearance was similar for gadopentetate, iohexol, and metrizoate. Plasma aldosterone levels were significantly higher in the two groups injected with iodinated contrast agents compared with the gadopentetate and saline groups in the 3-hour samples. During the 5 hours after injection, the excretion of brushborder enzymes LAP, ALP, and GGT was significantly higher for all contrast media compared with precontrast values and 0.9% NaCl controls. NAG, a lysosomal enzyme from tubular cells, showed a significant increase compared with precontrast values for all contrast media. Conclusions. Intrave- nous injection of gadopentetate in rabbits

showed nephrotoxicity of the same order as that of conventional iodinated contrast media. AUTHORS' ABSTRACT

The Anticoagulant Effects of Ionic and Nonionic Low-Osmolar Contrast Media in Dogs. Yasuhisa Kurisu, Shim- pei Tada. Invest Radiol 1992; 27:686- 688. (Y.K., Department of Radiology, Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, To- kyo 105, Japan)

Rationale and Objectives. The anticoagulant effects of ionic and nonionic low-osmolar contrast media were evaluated in vivo. Methods. The amount of clot deposited on guide wires placed in the femoral vessels of dogs was weighed 30 minutes after the injection of 2 mLikg of different contrast media. Six dogs were examined after injection of ioxaglate (ioxaglate group), six after injection of iopamidol (iopamidol group), and five after injection of saline (saline group). Re- sults. The mean weights of clot deposited on the guide wires in dogs in the ioxaglate group, the iopamidol group, and saline group were 30.5, 63.1, and 74.2 mg, respectively. The mean weight of clot deposition on the guide wires in the ioxaglate group was significantly less than in the iopamidol and saline groups, whereas there was no statistical difference between the mean weights of clot deposition in the iopamidol and saline groups. Conclusions. Ioxaglate, a low-osmolar, ionic contrast medium, has a greater anticoagulant effect than a low-osmolar, nonionic contrast agent, such as iopamidol. AUTHORS' ABSTRACT

MISCELLANEOUS

A Controlled Trial of Scheduled Re- placement of Central Venous and Pulmonary-Artery Catheters. David K. Cobb, Kevin P. High, Robert G. Saw- yer, e t al. N Engl J M e d 1992; 327:1062- 1068 (Barry M. Farr, Department of Med- icine, Box 473, University of Virginia Health Sciences Center, Charlottesville, VA 22908)

Background. The incidence of infection increases with the prolonged use of central vascular catheters, but it is unclear whether changing catheters every three days, as some recommend, will reduce the rate of infection. It is also unclear whether it is

safer to change a catheter over a guide wire or insert it at a new site. Methods. The authors conducted a controlled trial in adult patients in intensive care units who required central venous or pulmonary artery catheters for more than three days. Patients were assigned randomly to undergo one of four methods of catheter exchange: replacement every 3 days either by insertion at a new site (group 1) or by exchange over a guide wire (group 21, or replacement when clinically indicated either by insertion at a new site (group 3) or by exchange over a guide wire (group 4). Results. Of the 160 patients, 5% had catheter-related bloodstream infections, 16 percent had catheters that became colo- nized, and 9% had major mechanical complications. The incidence rates (per 1,000 days of catheter use) of bloodstream infection were three in group 1, six in group 2, two in group 3, and three in group 4; the incidence rates of mechanical complications were 14, four, eight, and three, respectively. Patients randomly assigned to guidewire-assisted exchange were more likely to have bloodstream infection after the first three days of catheterization (6% vs zero, P = .06). Inser- tions at new sites were associated with more mechanical complications (5% vs I%, P = .005). Conclusions. Routine replacement of central vascular catheters every 3 days does not prevent infection. Exchanging catheters with the use of a guide wire increases the risk of bloodstream infection, but replacement involving insertion of catheters at new sites increases the risk of mechanical complications. AUTHORS' ABSTRACT

Nonsurgical Closure of Femoral Pseudoaneurysms Complicating Car- diac Catheterization and Percutane- ous Transluminal Coronary Angio- plasty. Subodh K. Agrawal, Luiz Pinheiro, Gary S. Roubin, et al. J A m Coll Cardiol 1992; 20:610-615. (G.S.R., Inter- ventional Cardiology and Cardiac Cathe- terization Laboratories, 310 Lyons-Harri- son Research Bldg, 1919 Seventh Ave S, VAB Station, Birmingham, AL 35294- 0007)

Objectives. This study was performed to describe the initial experience and follow-up of ultrasound (US)-guided compression of pseudoaneurysms in patients receiving systemic anticoagulant or antiplatelet therapy, or both, after recent cardiac catheterization or percutaneous transluminal coronary angioplasty. Background. Femoral artery pseudoaneurysm formation after an inter-

332 Journal of Vascular and Interventional Radiology March-April 1993

ventional procedure is becoming more common as larger-caliber catheters and prolonged anticoagulant and antiplatelet therapy are being used. Traditional treatment of this complication has been surgical repair. This study describes a new method of closing femoral pseudoaneurysms by using external compression guided by Doppler color flow imaging. Methods. Fifteen patients, three undergoing cardiac catheterization and 12 undergoing coronary angioplasty, developed an expansile groin mass at the vascular access site diagnosed as a femoral artery pseudoaneurysm by means of Doppler US. Seven of the patients had undergone coronary stenting and were receiving postprocedural anticoagulant therapy. These patients underwent progressive graded mechanical (C-clamp) external compression guided by US. The mechanical compression was titrated to obliterate the vascular tracts to these aneurysms and maintain adequate flow in the femoral artery. Results. After an average compression time of 30 minutes (range, 10-120 minutes), these tracts remained closed. Follow-up US examination at 24 hours or later confirmed continued closure in all. Conclusions. This study suggests that nonsurgical closure of femoral pseudoaneurysms is feasible. This technique may be valuable in managing vascular access-related complications after diagnostic and interventional procedures, even in patients requiring prolonged anticoagulant therapy. AUTHORS' ABSTRACT

Single Dose Cephalosporin Prophy- laxis in High-Risk Patients Undergo- ing Surgical Treatment of the Bili- ary Tract. Michael D. Grant, Ronald C. Jones, Samuel E. Wilson, e t al. Surg Gy- necol Obstet 1992; 174:347-354. (R.C.J., Department of Surgery, Baylor Univer- sity Medical Center, 3500 Gaston Ave, Dallas, TX 75246)

During June 1985 through October 1986,292 patients considered to be at high risk for having postoperative complications develop underwent cholecystectomy and were evaluated in a multicenter, randomized, prospective, double-blind study. Risk factors included age greater than 70 years, acute cholecystitis within the previous 6 months, obstructive jaundice, obesity, and diabetes mellitus. One gram of cefamandole was administered intravenously to 144 patients and 148 patients received l gram of cefotaxime intravenously 30 minutes prior to skin incision. Culture-proved bactibilia was found in 55 patients, and 11 of the patients had choledocholithiasis. Of the risk factors considered to place patients a t high risk for postoperative infectious complications, obesity and acute cholecystitis proved to be the more common. However, age greater than 70 years, diabetes mellitus, and obstructive jaundice were more significant risk factors predisposing to bactibilia. The most common organisms isolated from the bile and gallbladder intraoperatively were Staphylococcus, Streptococcus, and Klebsi- ella species along with enterococcus, Esche-

richia coli, and diphtheroids. Clinically significant postoperative infections occurred in

A - eight patients, including six patients in the cefamandole n o u p and two patients in the - - cefotaxime group. Antibiotic concentrations were measured in the serum, muscle, subcutaneous fat, gallbladder, and bile, with cefamandole showing statistically significantly greater concentrations in bile, gallbladder, and muscle tissue. There was no statistical significance between the postoperative infection rates, total period of hospitalization or total hospital charges for each group. There- fore, there is no significant advantage between a single prophylactic dose of cefamandole versus cefotaxime for high-risk patients undergoing biliary tract operation. AUTHORS' ABSTRACT

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