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 hypert ensive 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 do se-dependent and significantly different from the effects of other ant ihypertensive agents at doses causing an equal degree of blood pressur e reduction. In large conduit arteries, hypertrophy of the vessels is reversed by converting enzyme inhibition both in hypertensive rats (st udies on central arteries) and in human (studies on peripheral arterie s) hypertension. The reduction of hypertrophy is associated with a dec rease in arterial stiffness, partly independent of blood pressure redu ction. These findings suggest that regression of structural vascular c hanges may contribute to both the decrease in the arteriolar resistanc e 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 improve ment in pulse pressure amplification produced by converting enzyme inh ibition.