MANAGEMENT OF ISOLATED SYSTOLIC HYPERTENSION

Isolated systolic hypertension (ISH) [systolic blood pressure (SBP) gr eater than or equal to 160mm Hg with diastolic blood pressure (DBP) <9 0mm Hg] is the commonest form of hypertension in the elderly, and acco unts for about 60% of all hypertensive conditions in the population ag ed over 65 years. It is associated with a significantly increased risk of cardiovascular and cerebrovascular morbidity and mortality. The la ndmark Systolic Hypertension in the Elderly Program (SHEP) study, publ ished in 1991, has shown that lowering the SEP in elderly patients wit h ISH results in a significant reduction in cardiovascular events. The se results have had a major impact on clinical practice in hypertensio n,On theoretical grounds, considering the pathophysiological mechanism s of ISH in the elderly, any drug which lowers total peripheral resist ance and/or arterial stiffness should reduce SEP effectively in these patients. This effect has been observed in outcome studies and short t erm clinical trials using a variety of drugs from the 4 major antihype rtensive classes: diuretics, beta-blockers, calcium channel antagonist s and ACE inhibitors. Other drugs, including alpha(1) antagonists, may also be effective. In general, there is compelling evidence to suppor t active treatment of any individual with an SEP greater than or equal to 160mm Hg. As in essential hypertension, the maximum benefit is gai ned by aggressive treatment of those individuals at highest risk becau se of coexisting cardiovascular risk factors. In these people, an SEP of 140 to 159mm Hg should be considered to be an indication for active management. Initial management should be by manipulation of lifestyle factors such as body-weight, salt and alcohol intake and aerobic exer cise. Drug therapy, generally well tolerated in low doses, should be c onsidered if SEP remains greater than or equal to 160mm Hg, or greater than or equal to 140mm Hg in the presence of multiple risk factors. T he choice of initial drug therapy should be influenced by the particul ar clinical situation. If there are no coexisting contraindications or co-indications for particular drugs, it is reasonable to begin treatm ent with a low dose of a thiazide-like diuretic, as used in the SHEP s tudy. However, in short term treatment trials calcium channel antagoni sts and ACE inhibitors have been shown to lower SEP effectively and ca n be used in the appropriate clinical context. beta-blockers appear to be less effective as monotherapy in ISH. Combination therapy is frequ ently required and can be effective and well tolerated if carefully ch osen.