The Journal of thoracic and cardiovascular surgery
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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.
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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.
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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.
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J. Thorac. Cardiovasc. Surg. · Aug 1996
Prognostic factors and long-term results after thymoma resection: a series of 307 patients.
Three hundred seven cases of patients who underwent operation for thymoma (196 of whom had myasthenia gravis) were analyzed to assess the prognostic values of Masaoka clinical staging, completeness of resection, histologic classification, history of myasthenia gravis, and postoperative radiotherapy. According to the Masaoka staging system, 135 thymomas were stage I, 70 were stage II, 83 were stage III, and 19 were stage IV. According to the Verley and Hollmann histologic classification system, 67 thymomas were type 1, 77 were type 2, 139 were type 3, and 24 were type 4. ⋯ We did not find any significant difference with respect to disease-free survival between patients who had postoperative radiotherapy and those who did not. In multivariate analysis, the sole significant prognostic factor was completeness of resection. On the basis of these findings, a new clinical-pathologic staging system is proposed.
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J. Thorac. Cardiovasc. Surg. · Aug 1996
Changes in autonomic response of the cerebral circulation after normothermic extracorporeal circulation.
Patients who undergo cardiopulmonary bypass frequently have neuropsychologic dysfunction. This study was undertaken to determine whether altered cerebral perfusion and vascular responses may in part lead to these neuropsychologic changes. Pigs were placed on normothermic cardiopulmonary bypass for 2 hours. ⋯ In vitro relaxation responses to sodium nitroprusside and forskolin (an adenylate cyclase activator) were similar in all experimental groups, suggesting that second-messenger mechanisms remain intact after normothermic cardiopulmonary bypass. In conclusion, basal cerebrovascular resistance and internal carotid artery blood flow are maintained if the systemic circulation and pressure are supported with fluid administration after cardiopulmonary bypass. Agonist-induced vasodilation of cerebral microvessels to cholinergic and beta-adrenoceptor stimulation are selectively impaired after normothermic cardiopulmonary bypass, whereas second-messenger mechanisms remain intact.