COMPARATIVE EFFECTS OF ANTIHYPERTENSIVE DRUGS ON SYSTOLIC BLOOD-PRESSURE

Importance of systolic over diastolic blood pressure measurements: Systolic pressure is known to be a more important independent cardiovascular risk factor than diastolic pressure in subjects over 50 years of age; after that age, a high incidence of two types of systolic hypertension is observed, sustained essential hypertension with a disproportionate increase in systolic pressure and isolated systolic hypertension. Effects of lacidipine on blood pressure in the elderly: The effects of vasodilators on blood pressure have been studied extensively. Recently, lacidipine, nitrendipine and enalapril were compared in a multicenter, randomly allocated, double-blind trial in elderly hypertensive patients with a disproportionate increase in systolic pressure treated for 8 weeks (n = 278). In these patients, supine systolic pressure decreased to a greater extent with lacidipine and enalapril than with nitrendipine, the difference between lacidipine and nitrendipine reaching statistical significance. In another trial, lisinopril produced a greater reduction in systolic pressure than atenolol. Finally, in a study in elderly patients with systolic hypertension, long-acting isosorbide dinitrate induced a selective sustained decrease in systolic pressure. Mechanisms of action of vasodilators. A fall in systolic blood pressure may be produced by vasodilators through a reduction in peripheral resistance with or without an active change in arterial compliance. Dihydralazine-like substances do not increase arterial compliance whereas angiotensin converting enzyme inhibitors, calcium entry blockers and nitrates tend to increase arterial compliance for the same decrease in mean arterial pressure.