LITERATURE REVIEW 295

grafting (CABG) or percutaneous transluminal coronary angio- plasty (PTCA) were evaluated to examine functional status out- comes during the first year of recovery. PTCA patients demon- strated improvement in all dimensions except for quality of social interaction. Significant improvements in all dimensions of func- tional status over the year were observed in the CABG group. PTCA patients demonstrated greater participation in routine daily and social activities for the first 6 months than did CABG patients, but this advantage disappeared at 1 year.

Biagina A, Maffei S, Baroni N, et al: Early assess- ment of coronary reserve after bypass surgery by dipyridamole transesophageal echocardiographic stress test. Am Heart J 120:1097-1101,199O

In this preliminary report of 11 men who underwent aortocoro- nary bypass surgery, a dipyridamole echocardiography stress test was performed before, soon after (68 to 130 minutes), and 1 week following surgery. The first and third tests were performed using a transthoracic approach; the second was performed transesoph- ageally to assess dipyridamole-induced changes in ventricular wall motion. Significant wall motion abnormalities were observed in all patients before surgery and in two patients immediately following surgery. One of these two patients developed a perioperative myocardial infarction, the other developed low-level effort angina postoperatively. Echocardiographic stress test results were the same 1 week after surgery as those obtained 2 hours after operation. Further studies are necessary to confirm this potential perioperative role of transesophogeal echocardiography.

Reichart SLA, Visser CA, Moulijn AC, et al: Intra- operative transesophageal color-coded Doppler echocardiography for evaluation of residual regurgi- tation after mitral valve repair. J Thorac Cardiovasc Surg 100:756-761,199O

Intraoperative transesophageal color Doppler echocardio- graphy postrepair was compared with postoperative cardiac cathe- terization for the assessment of residual regurgitation after mitral valve repair in 23 patients. Esophageal echocardiographic examina- tions were performed prior to sternotomy and after mitral valve repair before decannulation and after chest closure. The degree of mitral regurgitation was visually quantified on a 5point scale according to the extent of the regurgitant jet into the left atrium. This was compared with the degree of regurgitation by left ventricular cineangiography several weeks after operation visually quantified on a 5point scale. There was good correlation between the immediate postrepair and sternal closure transesophageal examinations as well as between the perioperative transesophageal and postoperative cineangiographic methods. Two patients were judged to have severe regurgitation similar to their preoperative study immediately after repair and had severe heart failure postoperatively. Each was reoperated on within 6 months for prosthetic valve implantation.

Pavlides GS, Hauser AM, Stewart JR, et al: Contri- bution of transesophageal echocardiography to pa- tient diagnosis and treatment: A prospective analysis. Am Heart J 120:910-914,199O

The diagnostic capability of transesophageal (TEE) versus transthoracic echocardiography (TTE) was prospectively examined in 86 consecutive patients undergoing clinical (nonoperative) cardiac evaluation. The conclusive diagnosis was possible in 95%

with TEE, whereas the same result was achieved in 48% by ‘ITE. TEE obviated cardiac catheterization, computed tomography scans, and magnetic resonance imaging scans more frequently than TIE. With the exception of mitral stenosis, TEE was the superior diagnostic tool for all lesions (aortic dissection, atria1 thrombi, mitral regurgitation, aortic insufficiency).

Montalescot G, Zapol WM, Carvalho A, et ah Neutralization of low molecular weight heparin by polybrene prevents thromboxane release and severe pulmonary hypertension in awake sheep. Circulation 82:1754-1764,199O

In an instrumented sheep model, the authors evaluated the effect of heparin type and heparin antagonist on the cardiopulmo- nary reaction to protamine neutralization. Protamine reversal of low molecular weight heparin and polybrene reversal of conven- tional unfractionated heparin induced a lo-fold increase in plasma thromboxane B, levels, threefold increase in pulmonary vascular resistance, and 25% decrease of PaO,. Severe reaction followed protamine reversal of unfractionated heparin. Polybrene (1 to 3 mgkg) reversal of low molecular weight heparin (1 to 3 mg/kg) produced no adverse cardiopulmonary reactions.

In a second article in the same journal, these authors demon- strated that heparin: protamine-induced pulmonary hypertension in sheep is thromboxane mediated. Pulmonary vasoconstriction and hypoxemia were prevented in the sheep model by pretreat- ment with a thromboxane AZ-receptor blocker, SQ 30741.

Wakefield TW, Bies LE, Wrobleski SK, et al: Impaired myocardial function and oxygen utilization due to protamine sulfate in an isolated rabbit heart preparation. Ann Surg 212:387-394,199O

The effects of protamine (25 kg, 50 kg, 250 ug/mL perfusion) without heparin and with heparin (0.1 IUI1.0 kg protamine) on left ventricular (LV) blood pressure, peak LV dP/dt, coronary artery flow, myocardial oxygen extraction, and oxygen consumption were measured in 30 isolated rabbit hearts. The addition of protamine exerted dose-dependent reductions in contractility, blood pressure, myocardial oxygen extraction, and oxygen consumption. The pres- ence of heparin had no effect. Decreases in contractility were modest (-7% to -16%) after administration of protamine in clinical concentrations (25 or 50 kg). High-dose protamine re- duced contractility by one third and produced asystole in 3 of 10 hearts exposed to this dose. This study supports previous concepts that myocardial responses contribute to protamine’s cardiovascu- lar effects in addition to the drug’s actions on the vasculature, platelets, and white blood cells.

Mallory DL, Shawker T, Evans G, et al: Effects of clinical maneuvers on sonographically determined internal jugular vein size during venous cannulation. Crit Care Med l&1269-1273,199O

Internal jugular vein (IJV) anatomy and the effect of recom- mended cannulation maneuvers were studied using two-dimen- sional ultrasonograpby in consecutive intensive care unit patients requiring IJV cannulation. The IJV was found to be thrombosed unilaterally in 4% of patients and sclerosed or congenitally absent in 2% of studied patients. All patients had at least one patent IJV. Trendelenburg position increased IJV lumen cross-sectional area from 1.18 to 1.62 cm’. Carotid artery palpation and needle advancement decreased IJV cross-sectional area.