Clinical and hemodynamic evaluation of coronary collateral vessels in coronary artery disease.

Abstract To appraise the functional significance of coronary collateral vessels, 78 consecutive patients with angina pectoris and at least 75 per cent obstruction in a major coronary vessel were studied clinically, hemodynamically, and angiographically and by stress testing. Forty-eight of them (62 per cent) had coronary collateral vessels. When patients with collaterals were compared with those without, the severity of angina pectoris and the number of positive treadmill ECG's were not statistically different. The patients with collaterals had a greater incidence of past myocardial infarction, 33 48 (68 per cent) vs. 8 30 (27 per cent) (P = 0.001); more extensive obstructive disease angiographically, 8.0 ± 0.4 vs. 6.3 ± 0.5 (P = 0.05); more abnormal pacing ventricular function curves, 22 23 (96 per cent) vs. 9 15 (60 per cent) (P = 0.01); and a greater incidence of left ventricular contraction abnormalities, 43 48 (90 per cent) vs. 16 30 (53 per cent) (P = 0.025). Patients who have coronary artery disease and collateral vessels cannot be distinguished from their counterparts without collaterals on a clinical basis except for a greater incidence of myocardial infarction in the former. Present evidence implies that collateral vessels may protect the patient by delaying the onset of angina pectoris, but when angina occurs these patients have more extensive coronary artery disease and greater myocardial dysfunction. In addition, collaterals, although not preventing, may limit the extent of myocardial infarction and reduce immediate mortality. The prognosis from the onset of angina pectoris may be worse in those patients with collateral vessels, however, because of their more extensive disease.