Hypertension: pathophysiology and treatment

morbidity and mortality because of its association with coronary heart disease, cerebrovascular disease and renal disease. The extent of target organ involvement (i.e. heart, brain and kidneys) determines outcome. North American studies have shown that hypertension is a major contributor to 500 000 strokes (250 000 deaths) and 1 000 000 myocardial infarctions (500 000 deaths) per annum. National surveys continue to reveal that hypertension is often not detected and, where diagnosed, is often inadequately treated. Amonghypertensive patients, only 25%appear to bewell controlled. This is particularly true of isolated systolic hypertension. Yet the prevalence of isolated systolic hypertension increases with age. Indeed, the proportion of subjects suffering from isolated systolic hypertension, as opposed to systolic and diastolic hypertension, increases from 20% in the under 40 yr to 80% in the 60–69 yr old, and to 95% in those >80 yr. There is increasing emphasis on the risk associated with systolic hypertension as the level of systolic pressure is a good predictor of coronary and cerebrovascular risk, especially in the elderly. Treatment of systolic hypertension with its wide pulse pressure is effective in terms of control of blood pressure and reduced morbidity, especially in older patients with high risk profile. Over the past decade the management of hypertension has changed with the recognition that there is no threshold below which elevated blood pressure causes no threat to health. Recent guidelines, including those of the British Hypertension Society, make it clear that treatment of isolated systolic hypertension is as important as that of systolic and diastolic hypertension. The threshold above which hypertension should be treated to prevent long-term complications is now 140/90 mmHg. Indeed, in Stage 1 hypertension, treatment of isolated systolic hypertension (systolic 140– 159 mm Hg, diastolic <90 mm Hg), reduces the prevalence of left ventricular hypertrophy, a predictor of future morbidity and mortality. There is also a 42% reduction of the risk of stroke and a reduction in the risk of dementia. The hypertension optimal treatment (HOT) study indicates that the treatment goal is to reduce blood pressure to 140/85 mm Hg. It is alsoestablishedthathighnormalbloodpressure (130–139/85–89 mm Hg) progresses to Stage 1 hypertension (>140/>90 mm Hg) in >37% of individuals <64 yr and >49% of those >65 yr. The British National Formulary recommends the following approach: