Results of coronary bypass more than 5 years after operation in 434 patients. Clinical, treadmill exercise and angiographic correlations

The long-term fate of 434 consecutive patients operated on between 1968 and 1971 was assessed. All patients were followed up for more than 60 months after operation (mean 70.7 months). Of the initial 434 patients, 98 died 0 to 74 (mean 31.1) months postoperatively. Of the 336 survivors, 152 reentered the hospital and underwent standardized clinical assessment. Angina was lessened in 93.4 percent (255 of 273) and absent in 51.3 percent (140 of 273) of these patients. Of patients under 65 years of age, 79.2 percent (152 of 192) were still working. Treadmill exercise tests performed in 107 patients showed an ischemic response in 44.9 percent (48 of 107) and an indeterminate response in 9.3 percent (10 of 107). The duration of the exercise, maximal pulse rate and double product all correlated well with the completeness of revascularization. In 176 patients with 256 grafts evaluated angiographically, the patency rate was 86.3 percent (221 of 256), and 94.3 percent of patients (166 of 176) had at least one patent graft. The average crude annual attrition rate after the first year was 2.3 percent per year, which approximates that of the general U.S. population after correction for age and sex. In the next 677 consecutive patients the survival rate after 5 years was 91.4 percent (including 4.7 percent operative mortality rate) compared with the survival rate of a similar normal population of 92.7 percent. The operative mortality rate of 7.1 percent in this early experience has been reduced to less than 2 percent in current experience. These results suggest that the coronary bypass procedure provides sustained symptomatic relief and may prolong life.