[Effects of nitroglycerin on the graft flow during aortocoronary bypass surgery].

The effects of an intravenous infusion of nitroglycerin on the hemodynamics and bypass graft flow to left coronary artery were studied in sixteen patients during coronary artery surgery. Systolic blood pressure, cardiac output and left ventricular minute work were not affected by 0.2 microgram/kg/min of nitroglycerin but graft flow volume especially diastolic graft flow increased significantly and the characteristics of flow velocity waveform in the graft became more diastolic predominant. By 1 microgram/kg/min of nitroglycerin a significant decrease in systolic blood pressure, cardiac output and graft flow were recognized, however diastolic graft flow was preserved despite of a decrease in left ventricular minute work. These findings demonstrate that nitroglycerin can be safely administered intravenously during aortocoronary bypass surgery, and suggest that nitroglycerin improves the balance of myocardial oxygen demand and supply, and relieves myocardial ischemia.