Hemodynamic effects of antihypertensive drugs. Possible implications for the prevention of atherosclerosis.

ABSTRACT

By lowering blood pressure, a number of hypertensive complications can be prevented, including congestive heart failure and such consequences of hypertensive arteriolar disease as nephropathy, intracerebral hemorrhage, and lacunar stroke. Whether atherosclerotic complications such as myocardial infarction can be prevented is more problematic and may depend on effects of the antihypertensive drugs other than the reduction of blood pressure, such as effects on plasma lipids and possibly hemodynamic effects. The following discussion summarizes a series of studies that suggest that the hemodynamic effects of antihypertensive drugs may be an important aspect of this problem. In studies in rhesus monkeys and hypertensive patients, antihypertensive drugs were shown to have differing effects on blood velocity and heart rate, important parameters in the genesis of arterial flow disturbances. In patients with carotid stenosis, hydralazine increased, whereas propranolol reduced, the occurrence of abnormal high-velocity flow patterns associated with turbulence and vortex formation. In a hypertensive (one kidney, one-clip) cholesterol-fed rabbit model, propranolol was significantly more effective than hydralazine in preventing the occurrence of aortic atherosclerosis. These observations suggest that the cardioprotective effect of beta blockers may extend to an antiatherosclerotic effect by hemodynamic mechanisms. This hypothesis is being further tested in patients with carotid stenosis.