Effects of nicardipine on coronary, vertebral and renal arterial flows in patients with essential hypertension

We examined the acute effects of a calcium antagonist, nicardipine, on hemodynamics and blood flow in the left anterior descending coronary (LAD), vertebral and renal arteries of essential hypertensive patients who had complained of chest pain and undergone cardiac catheterization. The blood flow velocities of the LAD, vertebral and renal arteries were measured using a Doppler guidewire and the arterial luminal diameters were measured from the arteriograms. The arterial blood flow was calculated by multiplying the blood flow velocity by the obtained vessel diameter. Coronary flow reserve was evaluated by injecting papaverine into the left coronary artery. After the baseline data had been obtained, intravenous infusion of nicardipine was started and the same hemodynamic, blood flow velocity and arterial diameter measurements were repeated. Blood pressure was decreased and cardiac output was increased by nicardipine infusion. There was a correlation between the decrease in systolic blood pressure and the increase in cardiac output (r= 0.71). The blood flow velocity in the LAD, vertebral and renal arteries tended to increase and there was an increase in the arterial luminal diameter. An increase in blood flow and a lowering of vascular resistance were observed for each artery (p<0.05). During nicardipine infusion, the diastolic blood flow in the LAD artery was improved (p<0.05); however, the maximal blood flow in the LAD artery induced by papaverine infusion remained unchanged. Therefore, there is evidence that coronary, vertebral and renal blood flows are improved by nicardipine infusion despite the acute blood pressure reduction.