Diltiazem alone and combined with nitroglycerin: effect on normal and diseased human coronary arteries

The vasodilatory effect of diltiazem and nitroglycerin on the large epicardial coronary arteries was evaluated in 26 patients with coronary artery disease. The luminal area of a normal and a stenotic coronary artery was determined at rest, after intracoronary administration of diltiazem, during submaximal exercise as well as 5 min after 1.6 mg sublingual nitroglycerin using biplane quantitative coronary arteriography. Twelve patients with no pretreatment prior to the exercise test served as group 1 (controls) and 14 patients with intracoronary administration of 2 to 3 mg diltiazem prior to the exercise test as group 2. Normal vessel: In the control group luminal area increased significantly during exercise (+23%, P less than 0.01) and after sublingual administration of nitroglycerin (+40%, P less than 0.001). In group 2 luminal area increased after intracoronary administration of diltiazem (+19%, P less than 0.01), during bicycle exercise (+23%, P less than 0.001) and after sublingual administration of nitroglycerin (+39%, P less than 0.001). Stenotic vessel: In the control group luminal area decreased significantly (-29%, P less than 0.001) during bicycle exercise but increased after sublingual administration of nitroglycerin at the end of the exercise test (+12%, NS vs. rest). In group 2 intracoronary administration of diltiazem was associated with a mild increase in stenosis area (+11%, P less than 0.05). There was a further increase in stenosis area during bicycle exercise (+23%, P less than 0.001 vs. rest) and after sublingual nitroglycerin (+32%, P less than 0.001). Coronary vasodilation of the stenotic segment was, however, significantly more pronounced after sublingual nitroglycerin in group 2 than 1 (+32% versus 12%, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)