Coronary flow and resistance reserve in patients with chronic aortic regurgitation, angina pectoris and normal coronary arteries

Abstract

Left ventricular hypertrophy has been found to be associated with a reduction of coronary vascular reserve, which could be responsible for episodes of myocardial ischemia. To evaluate coronary flow and resistance reserve in patients with chronic aortic regurgitation, coronary sinus blood flow and coronary resistance were measured before and after an intravenous dipyridamole infusion (0.14 mg/kg per min × 4 min) in eight control subjects and eight patients with aortic regurgitation, exertional angina pectoris and normal coronary arteriograms.Coronary flow reserve, evaluated by the dipyridamole/ basal coronary sinus blood flow ratio, and coronary resistance reserve, evaluated by the basal/dipyridamole coronary resistance ratio, were both significantly reduced in patients with aortic regurgitation (1.67 ± 0.40 versus 4.03 ± 0.52 in control subjects, p < 0.001 and 1.71 ± 0.50 versus 4.38 ± 0.88 in control subjects, p < 0.001, respectively). In patients with aortic regurgitation, basal coronary sinus blood flow was higher than in control subjects (276 ± 81 versus 105 ± 24 ml/min, respectively, p < 0.001) and basui coronary resistance was lower (0.31 ± 0.13 versus 0.95 ± 0.17 mm Hg/ml per min, respectively, p < 0.001), but coronary blood flow and resistance after dipyridamole were not significantly different in the two groups (461 ± 159 versus 418 ± 98 ml/min in control subjects, 0.19 ± 0.11 versus 0.22 ± 0.04 mm Hg/ml per min in control subjects, respectively).These data demonstrate that coronary reserve is severely reduced in patients with chronic aortic regurgitation and exertional angina. This reduction of coronary reserve might contribute to the pathogenesis of stress-induced episodes of myocardial ischemia and may participate in the progressive deterioration of left ventricular function in patients with chronic aortic regurgitation.