Results of coronary revascularization in patients with recent myocardial infarction

Abstract

Thirty-five patients underwent revascularization within 30 days of myocardial infarction. Group I (10 patients) underwent revascularization within 24 hours of infarction; Group II (nine patients), 2 to 7 days following infarction; and Group III (16 patients), 8 to 30 days after infarction. Indications for operation were persistent or recurrent pain following infarction, refractory ventricular arrhythmias, or persistent or recurrent pain associated with objective signs of reduced cardiac output. (A patient was not considered a surgical candidate if pain-free following infarction or if mechanical circulatory assistance was required in the treatment of cardiogenic shock.) There was an almost equal incidence of transmural and subendocardial myocardial infarction among the patients. Although severity of coronary vascular disease was the same for each of the three groups, left ventricular dysfunction was significantly more prevalent in Group I and Group III. There were no operative or late deaths during a short follow-up period (mean 9.8 months). Low morbidity and mortality in this very unstable group of patients was attributed to precise prebypass monitoring of rate-pressure product, Lead V 5 precordial electrocardiographic (ECG) changes, pulmonary capillary wedge pressure, and cardiac output. Pharmacologic intervention in the critical prebypass period included frequent use of intravenous propranolol and trinitroglycerin. Complications in the postoperative period (necessitating inotropic agents or intra-aortic balloon pumping) correlated with the degree of left ventricular dysfunction at the time of catheterization, rather than the infarction-revascularization interval. Satisfactory over-all graft patency (84 percent), patency of grafts into the infarcted area (82 percent), improvement in left ventricular function, and relief of angina pectoris were noted at the time of re-evaluation.