The five clinical subgroups of patients in the randomized studies included: stable angina with normal resting left ventricular function; stable angina with impaired left ventricular function; post-myocardial infarction without angina; congestive heart failure due primarily to ischemic heart disease; and patients previously asymptomatic who were discovered to have serious coronary artery disease. All of the above subgroups must have met specifically outlined clinical and angiographic criteria to be placed in the randomized subset. The other two subsets (as distinguished from subgroups) of the study included those patients who were unsuitable for randomization because surgery was the treatment of choice in the judgment of many physicians and those patients for whom medical management was the treatment of choice. The patients enrolled in both the registry and randomized trial were followed for a 10-year period. This allowed evaluation of the primary endpoints, death and myocardial infarction, and the secondary endpoints, angina, status, and quality of life.