Effect of nitroglycerin and papaverine on coronary flow in man

Abstract

Blood flow has been measured in 28 aortocoronary saphenous vein bypass grafts performed for chronic angina pectoris using the electromagnetic flowmeter. Nitroglycerin, 0.4 mg. intravenously or 0.1 mg. into the graft, and papaverine 30 mg. intravenously or 15 mg. into the graft, were studied. Intravenous nitroglycerin increased coronary flow a maximum of 4 per cent for 20 seconds followed by 23 per cent decline as mean arterial pressure fell 23 per cent. Intra-arterial nitroglycerin increased coronary flow 74 per cent in 15 seconds with return to control by 90 seconds. Intravenous papaverine elevated coronary flow 76 per cent at 30 seconds with stabilization of flow 15 to 20 per cent above control. Intra-arterial papaverine achieves a maximum flow of 215 per cent at 45 seconds with return to control at five minutes. Although nitroglycerin produces a small but significant rise in coronary flow it is doubtful whether this increase occurs with oral administration in the presence of coronary disease. Thus, the therapeutic effect of nitroglycerin lies in its systemic effects rather than in its coronary effect.