Differences in vasodilatory response to dipyridamole between patients with angina and normal coronary arteries and patients with successful coronary angioplasty

Background: Previous studies reported a reduced coronary blood flow reserve, assessed by the intravenous administration of dipyridamole, in patients with angina and normal coronary arteries, and early after successful coronary angioplasty, which suggests the presence of small coronary vessel dysfunction. This study aimed to establish whether the mechanisms of small coronary vessel disease in these two groups of patients are similar. Methods: The effects of the intracoronary infusion of adenosine and dipyridamole (maximum dose 2.7 and 7.5mg/min, respectively) on coronary blood flow velocity were assessed in 11 patients with engine and normal coronary arteries (group A) and in 12 patients immediately after successful coronary angioplasty (group B) using a 0.018' Doppler wire. Results: Baseline coronary blood flow velocity was significantly higher in group B than group A (34 ± 14 versus 19 ± 8 cm/s; P = 0.001). In group A, coronary/blood flow velocity was higher during adenosine than dipyridamole infusion (74 ± 17 versus 58 ± 21 cm/s; P