Isolated systolic hypertension in the elderly: new insights.

Isolated Systolic Hypertension (ISH) is associated with a several-fold excess risk of mortality from myocardial infarction, stroke and cardiac failure. Decreased compliance of large arteries and altered timing of reflected waves from peripheral vessels account for the selective increase in systolic pressure present in the elderly. Due to the wide variability of blood pressure frequently seen in old subjects, ISH is not easy to recognize and diagnosis requires a long period of observation. Ambulatory blood pressure monitoring proved helpful in distinguishing between patients with true ISH and subjects with exaggerated alarm reaction to the pressure measurement. Although the increased risk of cardiovascular mortality is well established for ISH, there has been much debate over whether available antihypertensive treatment can prevent or delay cardiovascular complications in ISH. The results of the SHEP study, recently published, demonstrate positive effects of treatment in ISH, as stroke (-35%) and all cardiovascular events (-32%) were significantly reduced by low-dose chlortalidone alone or associated to atenolol or reserpine.