Effects of residual coronary artery disease on results of coronary artery bypass grafting.

To assess the effects of residual coronary artery disease (non-revascularized coronary vessels) after coronary artery bypass grafting on symptoms and exercise left ventricular function, we categorized 77 patients into 3 groups according to the extent of residual coronary artery disease: group I (n = 17) had no residual coronary artery disease (residual score = 0); group II (n = 30) had light residual coronary artery disease (score of 1 to 9, mean 4.7); and group III (n = 30) had moderate residual coronary artery disease (score greater than or equal to 10, mean 23). Sixty patients were asymptomatic after coronary artery bypass grafting (14 in group I, 24 in group II, and 22 in group III), but the remaining patients had occasional angina pectoris. The resting left ventricular ejection fraction was significantly higher in group I than in the remaining 2 groups (56 +/- 18% in group I, 47 +/- 19% in group II, and 43 +/- 16% in group III, P less than 0.05). The exercise left ventricular ejection fraction was also significantly higher in group I (61 +/- 16% in group I, 51 +/- 18% in group II and 45 +/- 18% in group III, P less than 0.01). The ejection fraction response to exercise was abnormal in 5 patients in group I, 15 patients in group II, and 19 patients in group III. Thus, coronary artery bypass grafting results in symptomatic improvement, even in patients with residual coronary artery disease. The presence of residual coronary artery disease, however, may be a determinant of exercise left ventricular function in these patients.