A perspective on the three large multicenter randomized clinical trials of coronary bypass surgery for chronic stable angina.

Myocardial ischemia is an important determinant of survival in patients with coronary artery disease (CAD) and it may be silent. Coronary bypass surgery (CBS) is more effective than medical treatment in the relief of myocardial ischemia, anginal pain, and of events that are related to myocardial ischemia such as episodes of angina and left ventricular dysfunction caused by ischemia. Patients with chronic, stable angina assigned to CBS have an improved survival if they have left main CAD, three-vessel CAD with normal or impaired left ventricular function, proximal left anterior descending CAD that is part of two-vessel CAD, or two- or 3-vessel CAD with a positive exercise test for ischemia. In other respects, patients assigned to medical therapy fare as well as or better than those assigned to surgical therapy. Many issues that cause concern with regard to the randomized trials were considered in detail. The greatest problems are biostatistical tenets, small numbers of patients randomized in many of the subgroups, physician bias before and after randomization, crossovers, and inappropriate conclusions and unjustified extrapolations of the results. Timely, detailed, and comprehensive publication of the methods and results of these clinical trials is necessary. Meticulous, detailed, and critical reading of all of the published data is urged.