Related Experiment Videos
Captopril, but not nifedipine, improves endothelium-dependent vasodilation in hypertensive patients
1Department of Internal Medicine, University Hospital of Uppsala, Sweden.
Insights
Essential hypertension impairs endothelium-dependent vasodilation (EDV). Captopril, an ACE-inhibitor, improved EDV in hypertensive patients, unlike nifedipine. Long-term captopril treatment also enhanced EDV, suggesting a therapeutic benefit.
Area of Science:
- Cardiovascular Pharmacology
- Hypertension Research
- Endothelial Function Studies
Background:
- Essential hypertension is linked to impaired endothelium-dependent vasodilation (EDV).
- Understanding the effects of antihypertensive drugs on EDV is crucial for managing hypertension.
- Angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers are common treatments for hypertension.
Purpose of the Study:
- To investigate the impact of captopril (ACE-inhibitor) and nifedipine (calcium antagonist) on EDV in hypertensive patients.
- To compare the effects of these drugs on endothelium-independent vasodilation (EIDV).
- To assess the long-term effects of captopril on EDV and blood pressure.
Main Methods:
- Randomized, double-blind study in 23 untreated hypertensive patients and a normotensive control group.
- Intra-arterial infusions of methacholine (MCh) for EDV and sodium-nitroprusside (SNP) for EIDV.
- Evaluation before and 1 hour after single doses of captopril (25 mg) or nifedipine (10 mg).
- A pilot study assessed 5 hypertensive patients after 3 months of captopril treatment.
Main Results:
- Hypertensive patients showed attenuated MCh-induced vasodilation compared to controls.
- Captopril significantly potentiated MCh-induced vasodilation (+32%) but not SNP-induced vasodilation.
- Nifedipine did not significantly alter responses to MCh or SNP.
- Long-term captopril treatment (3 months) significantly improved MCh-induced vasodilation (+34%) and reduced blood pressure.
Conclusions:
- Essential hypertension is characterized by impaired EDV.
- Captopril acutely improves EDV in hypertensive patients, an effect not observed with nifedipine.
- Long-term captopril therapy demonstrates sustained beneficial effects on EDV in hypertensive individuals.
Abstract:
The present study aimed to investigate the influence of the angiotensin-converting enzyme (ACE)-inhibitor captopril and the Ca-antagonist nifedipine on endothelium-dependent vasodilation (EDV) in the forearm of hypertensive patients. Twenty-three middle-aged untreated hypertensive patients underwent evaluation of EDV and endothelium-independent vasodilation (EIDV) in the forearm, by means of local intra-arterial infusions of methacholine (MCh, evaluating EDV) and sodium-nitroprusside (SNP, evaluating EIDV), before and 1 h after intake of either captopril (25 mg) or nifedipine (10 mg) in a randomised, double-blind fashion. A matched normotensive control group was investigated at baseline conditions only. Five of the hypertensives were also evaluated after 3 months of treatment with captopril 25 mg twice daily in an open pilot study. First, the vasodilation induced by methacholine (MCh), but not SNP, was significantly attenuated in the hypertensive patients compared to the normotensive controls (P < 0.001 at MCh 4 microg/min). Second, although the two drugs induced a similar decline in blood pressure (BP) 1 h after administration (-11 to 10 mm Hg/-8 to 7 mm Hg), captopril significantly potentiated the vasodilator response to MCh (+32+/-13%, MCh 4 micr og/min, P < 0.01) but not SNP, while nifedipine did not significantly alter the response to either MCh or SNP. The improvement in vasodilator response to MCh induced by captopril was closely related to the reduction in BP (r = 0.72, P < 0.01). Third, in the pilot study, 3 months of captopril treatment induced a significant potentiation of the vasodilator response to MCh (+34+/-17%, MCh 4 microg/min, P < 0.05) in parallel with a significant BP reduction (-22+/-24/13+/-13 mm Hg, P < 0.05), while the response to SNP was unchanged. In conclusion, the present study confirmed that essential hypertension is associated with a defect in EDV. Furthermore, an improvement in EDV was seen in hypertensive patients shortly after administration of captopril, but not nifedipine. In addition, a significant beneficial effect on EDV was seen in a small pilot study during long-term treatment with captopril.