Effect of captopril and enalapril on endothelial function in hypertensive patients.
Endothelium-dependent vasodilation is impaired in patients with essential hypertension. The objective of this study was to determine whether long-term treatment with angiotensin-converting enzyme inhibitors improves endothelium-dependent vasodilation in forearm resistance vessels of patients with hypertension. Furthermore, since tissue thiols may be relevant to nitric oxide-mediated vasodilation, we queried whether an angiotensin-converting enzyme inhibitor with a sulfhydryl group preferentially augments endothelium-dependent vasodilation in these individuals. The study included 24 patients with essential hypertension (mean age, 45 +/- 2 years) and 20 normotensive subjects (mean age, 47 +/- 1 years). Methacholine chloride (0.3 to 10 micrograms/min) was infused via the brachial artery to assess endothelium-dependent vasodilation in forearm resistance vessels. Nitroglycerin (1 to 30 micrograms/min) was administered to evaluate endothelium-independent vasodilation. Forearm blood flow was determined by venous occlusion strain-gauge plethysmography. Forearm vascular function studies were performed in hypertensive patients before and 7 to 8 weeks after randomization to either captopril or enalapril, angiotensin-converting enzyme inhibitors with and without a sulfhydryl moiety, respectively. Normotensive subjects were studied on only one occasion. Before treatment, the forearm vasodilative response to methacholine was attenuated in hypertensive compared with normotensive subjects (P < .01). The effects of nitroglycerin on forearm blood flow did not differ significantly between the two groups. Both captopril and enalapril reduced mean blood pressure in the hypertensive subjects (12 +/- 2 versus 15 +/- 3 mm Hg, respectively; P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
Creager
M A
MA
Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass. 02115.
Roddy
M A
MA
D000328:Adult; D000368:Aged; D002216:Captopril / Q000494:pharmacology / Q000627:therapeutic use*; D004656:Enalapril / Q000494:pharmacology / Q000627:therapeutic use*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005542:Forearm / Q000098:blood supply; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology; D005996:Nitroglycerin / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D016210:Methacholine Chloride; D009569:Nitric Oxide; D004656:Enalapril; D002216:Captopril; D005996:Nitroglycerin