Resistance and conduit arteries following converting enzyme inhibition in hypertension.

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.