Data are now available from many centers on the results of the coronary artery bypass operation. Approximately 85 percent of the patients who survive the procedure experience relief of angina and 60 percent have no further chest pain. Similarly, 70 to 85 percent of the patients have improved results on objective testing, and this improvement seems to correlate fairly well with the patency of the bypass grafts. Data from various institutions on effects on ventricular function have not been consistent, but there is some evidence that myocardial contractility for segments with a patent graft can be improved, particularly when there is no infarction and the preoperatlve ventricular wall motion is moderately depressed. The operative mortality rate for patients with stable angina is less than 6 percent in most centers and appears to be related to the quality of ventricular function. The mortality rate in patients with unstable angina is considerably higher in most institutions. Although vein patency is reduced to between 65 and 75 percent 1 year postoperatlvely, the occlusion rate over the next 2 years appears to be only 5 to 6 percent. It is too early to state definitively whether surgery can prevent infarction in patients with stable or unstable angina. However, there is fairly good evidence that bypass surgery can prevent infarction if it is carried out within 4 hours after the onset of coronary occlusion. The results from several centers suggest that bypass surgery may favorably influence the annual survival rate in patients with stable angina. There are not enough controlled data to say whether the procedure can extend life in patients with unstable angina, which is a highly lethal disease, particularly for individuals with continuing severe angina. Bypass surgery would appear to be of value for this group of patients.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine