LITERATURE REVIEW 765

pressure greater than 10 mmHg in the two groups, respectively. Hypotension was treated primarily with vasopressors in the EVLW group and with volume expansion and vasopressors in the wedge pressure patients. Cumulative input-output differences were +2239 mL in the wedge pressure group versus +142 mL in the EVLW group. EVLW, ventilator and ICU days were significantly reduced by awes- sive diuresis and fluid restriction based on EVLW measurements.

Horst HM, Dlugos S, Fath JJ, et al: Coagulopathy and intraoperative blood salvage (IBS). J Trauma 32&l&653,1992

One hundred fifty-four trauma patients received an average of 7.97 units of washed, centrifuged shed red blood cells, which accounted for 30% to 40% of their total blood replacement. Prolongation of prothrombin (PT) and partial thromboplastin times (PTT) was directly related to number of units transfused; moderate-to-severe abnormalities of PT and PTT occurred in 31% of patients. Patients not developing significant coagulation time abnormalities received less than 25 combined units of blood (washed shed blood and homologous units). PT and PTI prolonga- tion were seen in patients receiving greater than 15 units of washed shed blood and greater than 50 combined units. No other measures of hemostatic function were assayed. It is not possible to determine the role that the reinfused washed blood played relative to other factors seen in multiply transfused patients. The authors concluded that patients receiving more than 15 units of washed shed blood require careful coagulation monitoring. Interestingly, 58 of the 66 patients with bowel injury received shed blood and showed no increase in infection, but did develop prolongation of PT and PTT at lower levels of transfusion.

Walls JT, Curtis JJ, Silver D, et al: Heparin- induced thrombocytopenia in open heart surgical patients: Sequela of late recognition. Ann Thorac Surg 53:787-791,1992

Over a lo-year period, heparin-induced thrombocytopenia was diagnosed in 82 of 4,261 open heart surgical patients (1.9%) in one institution’s experience. Heparin-dependent antiplatelet antibody was diagnosed preoperatively in 12 patients and postoperatively in 70 patients. Patients with preoperative recognition of heparin- induced thrombocytopenia had total abstinence of heparin after cardiopulmonary bypass in the postoperative period. Three bleed- ing complications occurred in this group; there were no thrombotic events or mortality. Patients with late recognition of heparin- dependent antibody had continued postoperative heparin expo- sure (heparin flushes, heparin-coated catheters). Thirty-seven patients (53%) had bleeding complications, thirty-one (44%) thrombotic complications, and mortality occurred in 23 patients (33%). Heparin-induced thrombocytopenia must be suspected and diagnosed early to avoid morbidity and mortality.

Coley CM, Field TS, Abraham SA, et al: Usefulness of dipyridamole-thallium scanning for preoperative evaluation of cardiac risk for nonvascular surgery. Am J Cardiol69:1280-1285,1992

One hundred consecutive patients with known or suspected coronary artery disease underwent dipyridamole-thallium scanning before nonvascular surgery. Major cardiac events occurred in 9 patients (9%). Multivariate analysis revealed that age greater than 70 years, history of heart failure, and thallium redistribution during dipyridamole-thallium scanning were independent predictors of risk. There were no cardiac events in the forty-five patients without the two clinical variables (age, heart failure). For patients with one

or both clinical markers, thallium redistribution correlates with a substantial change in perioperative risk. The authors conclude that dipyridamole-thallium scanning is most useful in assessing risk in selected patients at intermediate or high risk by clinical descriptors.

Lalka SG, Sawada SG, Dalsing MC, et al: Dobu- tamine stress echocardiography as a predictor of cardiac events associated with aortic surgery. J Vast Surg 15:831-842,1992

The ability of dobutamine stress echocardiography to predict perioperative cardiac events was evaluated in 60 patients undergo- ing elective aortic revascularization. Patients undergoing coronary angioplasty or bypass on the basis of dobutamine stress echocardi- ography were excluded from the study. Echocardiographic images of wall motion were obtained at rest and during incremental dobutamine infusion. Dobutamine stress echocardiography results were stratified as follows: no wall motion abnormalities (group I), resting wall motion abnormalities unchanged with stress (group II), stress-induced worsening of resting wall motion abnormalities (group III), new-onset wall motion abnormalities with stress (group IV). Postoperative cardiac events (cardiac death. myocar- dial infarction, unstable angina, asymptomatic increase in creatine phosphokinase MB) occurred in 4.6% of patients with a normal stress echocardiogram (group I). In contrast, postoperative cardiac events occurred in 12.5% of group II patients, 14.3% of group III patients and 39.1% of group IV patients.

Marcovitz PA, Armstrong WI? Accuracy of dobut- amine stress echocardiography in detecting coronary artery disease. Am J Cardio169:1269-1273,1992

Dobutamine stress echocardiography (DSE) was performed in 141 patients undergoing coronary arteriography. For all patients DSE has a sensitivity of 96%, specificity of 66%, and overall accuracy of 89% for prediction of coronary disease (CAD) re- vealed at subsequent catheterization. For the 53 patients with normal resting wall motion, sensitivity was 87% and specificity 91%. In comparison with wall motion analysis, la-lead electrocar- diograms during dobutamine infusion revealed ischemic changes in only 17% of patients with CAD. No serious complications oc- curred. The authors conclude that though DSE is an accurate means for detecting CAD, its specificity is hindered in patients with resting wall motion abnormalities.

REVIEW ARTICLES

Piccano E: Stress echocardiography. From patho- physiological toy to diagnostic tool. Circulation 85: 1604-1612,1992

This article reviews the basic features of stress echocardiography including the pathophysiological rationale and echocardiographic signs of transient myocardial ischemia. The use of dipyridamole and dobu- tamine as pharmacologic stressors to overcome the technical limitation of exercise echocardiography is discussed. The physiologic basis of the pharmacologic stresses is presented and dipyridamole and dobutamine stress echocardiography compared. Clinical results, diagnostic useful- ness, and future of the techniques are discussed.

ACKNOWLEDGMENT

Papers review in this issue were selected from those published in the following journals: American Heart Journal, American Journal of Cardiology, American Review of Respiratory Disease, Annals of Thoracic Surgery, Circulation, Journal of Trauma, Journal of Vascu- lar Surgery, and Journal of Thoracic and Cardiovascular Surgery.