Imidapril, but not amlodipine, significantly increased L-arginine-induced renovascular relaxation (renal plasma flow 9.6% to 14.4%, P<0.05) in patients with essential hypertension.
RCT (n=27)
Double-blind
randomly assigned
Does imidapril improve L-arginine-induced renovascular relaxation compared to amlodipine in patients with mild to moderate essential hypertension?
ACE inhibition with imidapril, but not calcium antagonism with amlodipine, improves endothelium-dependent renovascular relaxation in essential hypertension, likely via increased nitric oxide production.
p-value: p=<0.05
Endothelial function has been shown to be impaired in patients with essential hypertension. The purpose of the present study was to determine whether antihypertensive drug therapy improves impaired endothelium-dependent renal vasorelaxation in essential hypertensive patients without atherosclerosis. We evaluated the effects of intravenous infusion of L-arginine (500 mg/kg given over 30 minutes) on systemic and renal hemodynamics in 27 patients with mild to moderate essential hypertension who were randomly assigned to treatment with either the angiotensin-converting enzyme inhibitor imidapril or the calcium antagonist amlodipine for 12 weeks in a double-blind fashion. After the 12 weeks, the decrease in blood pressure was similar in the imidapril (n=14) and amlodipine (n=13) groups. The increase in renal plasma flow was also similar in both groups. L-Arginine-induced renovascular relaxation was increased by imidapril (renal plasma flow, 9.6+/-5.1% to 14.4+/-7.4%; renal vascular resistance, -10.4+/-8.1% to -16.7+/-9.2%, P<0.05, respectively) but not by amlodipine. Urinary excretion of nitrite/nitrate in response to L-arginine was significantly increased by imidapril (90+/-29% to 134+/-63%, P<0.05) but remained unchanged by amlodipine. These findings suggest that angiotensin-converting enzyme inhibition improves the impaired endothelium-dependent renovascular relaxation in patients with essential hypertension due to the increase in nitric oxide production and that the reduction in blood pressure with a calcium antagonist does not play a major role in the potentiation of L-arginine/nitric oxide-mediated effects.
Higashi et al. (Wed,) conducted a rct in mild to moderate essential hypertension (n=27). imidapril vs. amlodipine was evaluated on L-Arginine-induced renovascular relaxation (renal plasma flow) (p=<0.05). Imidapril, but not amlodipine, significantly increased L-arginine-induced renovascular relaxation (renal plasma flow 9.6% to 14.4%, P<0.05) in patients with essential hypertension.