Unstable angina: A clinicoarteriographic correlation and long-term results of early myocardial revascularization

Abstract

Between June, 1973, and June, 1978, 71 patients with unstable angina underwent emergency coronary artery bypass grafting. Fifty-four patients (76%) gave a previous history of stable angina. Seventy patients (99%) were found to have left main-stem stenosis or severe disease in the anterior descending artery proximal to the first septal branch. Intra-aortic balloon counterpulsation was instituted prior to angiography in 12 patients and in a further nine patients prior to induction of anesthesia as a result of intractable and continuous angina. There were no deaths associated with investigations. All patients underwent operation within 48 hours of admission to hospital. A total of 188 grafts were inserted (2.7 grafts per patient). There were three early deaths (4.2%) and two late deaths (2.8%) during a follow-up period varying between 6 and 62 months (mean 29 months). Actuarial analysis showed a 92% survival rate at 4 years. Five patients (7%) sustained perioperative infarction and four patients (5.9%), late myocardial infarction. All patients were symptomatically improved following operation and 51 (80%) are entirely asymptomatic. Fifty-two patients were electively reinvestigated following operation at times varying between 2 weeks and 58 months (mean 20 months). The overall graft patency rate was 91%. Changes in left ventricular function were analyzed by computerized radial analysis of segmental wall motion in 39 patients. Significant improvement in segmental wall motion occurred in 14 (70%) of 20 patients with abnormal wall motion preoperatively and appeared to be closely related to graft patency. There was a significant increase in ejection fraction from a mean of 0.59 to a mean of 0.69 following operation. Patients with unstable angina may be safely investigated during the acute phase and subsequent revascularization may be undertaken with low early and late mortality rates. Intra-aortic balloon counterpulsation is a valuable adjunct to the management of these patients.