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Resistance and conduit arteries following converting enzyme inhibition in hypertension
M E Safar1, L M van Bortel, H A Struijker-Boudier
1Department of Internal Medicine, Broussais Hospital, Paris, France.
Insights
Angiotensin I-converting enzyme inhibition reverses arterial structural changes in hypertension. This improves arterial stiffness and compliance, contributing to blood pressure reduction and enhanced pulse pressure amplification.
Area of Science:
- Cardiovascular Medicine
- Pharmacology
- Vascular Biology
Background:
- Hypertension is characterized by structural alterations in resistance and conduit arteries.
- Previous studies suggest angiotensin I-converting enzyme (ACE) inhibition impacts arterial structure.
Purpose of the Study:
- To investigate the effects of ACE inhibition on arterial structure in hypertension.
- To determine if ACE inhibition-induced arterial changes are independent of blood pressure reduction.
Main Methods:
- Studies were conducted in hypertensive rats and human subjects.
- Evaluated changes in resistance and conduit arteries, including media to lumen ratio and hypertrophy.
- Compared ACE inhibition effects with other antihypertensive agents.
Main Results:
- ACE inhibition reduced the media to lumen ratio in resistance arteries in a dose-dependent manner in rats.
- Hypertrophy of large conduit arteries was reversed by ACE inhibition in both rats and humans.
- Reduced arterial stiffness and improved large artery compliance were observed, partly independent of blood pressure reduction.
Conclusions:
- ACE inhibition promotes regression of structural vascular changes in hypertension.
- These structural improvements contribute to decreased arteriolar resistance and enhanced large artery compliance.
- ACE inhibition may lower blood pressure and improve pulse pressure amplification through vascular remodeling.
Abstract:
Alterations in the structure of resistance and conduit arteries are a characteristic hallmark in hypertension. Studies carried out in hypertensive rats and in humans suggest that angiotensin I-converting enzyme inhibition has an effect on arterial structure of resistance arteries. In hypertensive rats the reduction of the media to lumen ratio is dose-dependent and significantly different from the effects of other antihypertensive agents at doses causing an equal degree of blood pressure reduction. In large conduit arteries, hypertrophy of the vessels is reversed by converting enzyme inhibition both in hypertensive rats (studies on central arteries) and in human (studies on peripheral arteries) hypertension. The reduction of hypertrophy is associated with a decrease in arterial stiffness, partly independent of blood pressure reduction. These findings suggest that regression of structural vascular changes may contribute to both the decrease in the arteriolar resistance and the improvement in the buffering function of large arteries. The decrease in arteriolar resistance and the improvement of large artery compliance may participate in blood pressure reduction and an improvement in pulse pressure amplification produced by converting enzyme inhibition.