Comparison of isradipine and enalapril effects on regional carotid circulation in patients with hypertension with unilateral internal carotid artery stenosis.
This randomized, double-blind, placebo-controlled study was aimed at detecting cerebrovascular effects of isradipine and enalapril in patients with moderate hypertension depending on the presence and grade on unilateral stenosis of internal carotid artery (ICA). We evaluated carotid vascular resistance by using Doppler analysis and regional cerebral blood flow (rCBF) by using 133Xe-clearance technique before and after a single 5-mg oral dose of isradipine, enalapril, or placebo. Their effects were randomly and consecutively tested in 73 patients with essential hypertension subdivided into three groups: without carotid occlusive lesions, with moderate (50-75%), and with severe (76-99%) unilateral asymptomatic ICA stenosis. There were no differences in age, gender, and antihypertensive effects of the drugs between these three subgroups. Three major variants of cerebrovascular drug effects were observed: absence of changes (variant I), decrease in carotid vascular resistance with increase in rCBF and elimination of side-to-side asymmetry (variant II), and increase in carotid vascular resistance with further reduction of rCBF ipsilaterally ICA stenosis, and increased side-to-side asymmetry (variant III). Frequency of variant III was significantly higher in patients with severe ICA stenosis. Enalapril produced variant I of cerebrovascular effects in most patients examined; variant III was observed only in 13% of patients with severe ICA stenosis. Isradipine produced variant I of cerebrovascular effects much less frequently than did enalapril. For this drug, variant II was most typical in patients without ICA stenosis and with moderate ICA stenosis. In 43.5% of patients with severe ICA stenosis, however, isradipine produced reduction of cerebral perfusion. Presumably the presence of ICA stenosis, especially >75%, increases the risk of cerebrovascular disorders in antihypertensive therapy. In patients with severe ICA stenosis, treatment with enalapril appears to be safer than that with isradipine.
Akopov
S E
SE
Department of Neurology, the Armenian National Institute of Health, and the Republican Diagnostic Center Diagnostica, Yerevan.
Simonian
N A
NA
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use*; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D004656:Enalapril / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy*; D017275:Isradipine / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011875:Radionuclide Angiography; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance / Q000187:drug effects
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D004656:Enalapril; D017275:Isradipine