The Journal of thoracic and cardiovascular surgery
-
J. Thorac. Cardiovasc. Surg. · Aug 1996
Comparative StudyEffects of failure of the right side of the heart and increased pulmonary resistance on mechanical circulatory support with use of the miniaturized HIA-VAD displacement pump system.
This experimental study was designed to assess the influence of failure of the right side of the heart or pulmonary hypertension, or both, on the performance of a novel miniaturized left ventricular assist device. In small-sized dogs (n = 50) ischemic global left ventricular failure was induced and support was provided by the HIA-VAD displacement pump (stroke volume 10 or 25 ml) installed as a left ventricular assist device. In three groups of animals (n = 10 each) pulmonary hypertension was created before induction of global left ventricular failure. ⋯ However, when right ventricular failure was added (that is, pulmonary hypertension, left ventricular failure, left ventricular support, and right ventricular failure during support with the left ventricular assist device) left atrial pressure dropped to negative values (p < 0.05) and cardiac index progressively deteriorated. When, in an additional group of dogs, biventricular support was installed in the latter regimen, circulation was initially well supported but oxygenation deteriorated in 60% of cases. We conclude that (1) adequate right ventricular function was indispensable during support with the left ventricular assist device, (2) the combination of pulmonary hypertension and right ventricular failure led to the "low left ventricular assist device output syndrome," and (3) biventricular mechanical support in the presence of pulmonary hypertension may be complicated by the alveolar leakage syndrome.
-
J. Thorac. Cardiovasc. Surg. · Aug 1996
Unifocalization for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries.
To extend the indications for corrective operation in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries, surgical procedures were done to unify the blood sources for pulmonary perfusion. Since December 1985, 50 patients have undergone unifocalization at ages from 2 months to 26 years with a mean of 6 +/- 7 years. In total, 84 staged unifocalization procedures and 5 other palliative procedures were done in 49 patients. ⋯ One patient (4%) died shortly after intracardiac repair because of thrombosis within the pulmonary arteries. Postoperative catheterization showed that pulmonary vascular resistance was correlated significantly with the number of pulmonary vascular segments functioning rather than with the condition of the central pulmonary arteries. We conclude that surgical unifocalization is a feasible procedure before subsequent intracardiac repair, even in patients with critically hypoplastic or absent central pulmonary arteries.
-
J. Thorac. Cardiovasc. Surg. · Aug 1996
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of temperature management during cardiopulmonary bypass on neurologic and neuropsychologic outcomes in patients undergoing coronary revascularization.
Several studies suggest that normothermic ("warm") bypass techniques may improve myocardial outcomes for patients undergoing cardiac operations. Normothermic temperatures during cardiopulmonary bypass may, however, decrease the brain's tolerance to the ischemic insults that accompany all cardiac procedures. To assess the effect of bypass temperature management strategy on central nervous system outcomes in patients undergoing coronary revascularization, 138 patients were randomly assigned to two treatment groups: (1) hypothermia (n = 70), patients cooled to a temperature less than 28 degrees C during cardiopulmonary bypass, or (2) normothermia (n = 68), patients actively warmed to a temperature of at least 35 degrees C. ⋯ Performance on at least one neuropsychologic test deteriorated in the immediate postoperative period in more than one half of all patients in both treatment groups but returned to preoperative levels approximately 1 month after the operation in most (85%). This pattern was not related to bypass temperature management strategy. We conclude that active warming during cardiopulmonary bypass to maintain systemic temperatures > or = 35 degrees C increases the risk of perioperative neurologic deficit in patients undergoing elective coronary revascularization.
-
J. Thorac. Cardiovasc. Surg. · Aug 1996
Comparative StudyApplicability of intermittent global ischemia for repeat coronary artery operations.
Despite the increasing popularity of cardioplegic techniques there is no consensus as to the optimal myocardial protective technique for first-time or repeat coronary artery bypass grafting. Intermittent global ischemia was used in 159 consecutive patients (142 male; 17 female) undergoing repeat coronary artery bypass grafting during a 6-year period (1987 to 1992). The median age of the patients was 60 years (90% confidence interval: 47 to 70 years) and the median interval from the first operation was 9 years (90% confidence interval: 2 to 14 years). ⋯ Eight patients died in the follow-up period, which resulted in an estimated survival of 80% at 5 years. At a mean follow-up period of 2 years (and with or without antianginal medication) 83% of patients had no or minimal angina, 12% had angina on moderate exertion, and 5% had angina on minimal exertion. In comparison with other current series of repeat coronary revascularization our results suggest that repeat coronary artery bypass grafting can be done with intermittent global ischemia with early and intermediate results at least equivalent to those obtained with cardioplegic methods.
-
J. Thorac. Cardiovasc. Surg. · Aug 1996
Comparative StudyProtamine-induced hypotension in heart operations: application of the concept of ventricular-arterial coupling.
Protamine sulfate often causes hypotension during heparin neutralization. The concept of ventricular-arterial coupling was applied to determine whether a negative inotropic effect or a vasodilating effect of protamine was the major contributing factor to this hypotension. Thirty-five patients who underwent cardiac operations were studied during operation by measuring instantaneous left ventricular pressure and aortic flow to examine the end-systolic pressure-volume relationship. ⋯ Although the decrease in end-systolic elastance at midpoint (control 3.08 +/- 1.61 mm Hg/ml, midpoint 2.92 +/- 1.68 mm Hg/ml) did not reach statistical significance, end-systolic elastance significantly decreased at maximum (2.63 +/- 1.46 mm Hg/ml; p < 0.01). Continuous measurements showed that the decreases in mean arterial pressure and effective arterial elastance always preceded the depression of end-systolic elastance and that afterload reduction by vasodilating effect of protamine was the mechanism most likely to have initiated the hypotension. Delayed decrease in contractility may be ascribed to reduced coronary perfusion pressure caused by vasodilation or to a direct effect of protamine.