Drug-induced modification of vascular structure: effects of antihypertensive drugs

It has long been realized that hypertension causes alterations in the peripheral vasculature, with the arterial wall becoming thicker and the lumen relatively smaller. This is particularly true in small resistance arteries, but larger vessels are also affected. The precise mechanisms remain to be determined, although it is highly likely that growth-promoting autacoids are involved as well as mechanical forces. Numerous studies of hypertension in animal models and a few in hypertensive humans have tried to establish the reversibility of these changes after successful lowering of blood pressure. Too few data are available to form firm conclusions, but thiazides and hydralazine-like vasodilators appear to have only a minimal effect on the vasculature. On the other hand, angiotensin-converting enzyme inhibitors are clearly effective, and alpha-blockers may be active. However, it is difficult to derive even tentative conclusions from the available information on calcium antagonists and beta-blockers. These results are discussed in the context of future therapeutic and investigative approaches.