In the past, evaluation and treatment of hypertension were often based on the lower (diastolic) values and it was the diastolic hypertension that was thought to pose many of the risk factors described above. Recent studies indicate, however, that the systolic hypertension (higher of the two values) is responsible for much of the morbidity and mortality associated with elevated blood pressures. Isolated systolic hypertension (ISH) is defined as a systolic pressure greater than 160 mm Hg and a normal diastolic pressure (less than 90 mm Hg).

The National Health and Nutrition Examination Survey (NHANES) III investigated many of the risks of hypertension as well as the impact of diastolic and systolic hypertension on development of heart disease. Optimal control of isolated systolic hypertension (ISH) was responsible for the highest reduction in adverse cardiac effects such as myocardial infarction. Of note, the reduction was more pronounced in women (56% reduction as compared to 37% in men).

Other studies are beginning to show more evidence for the role of systolic hypertension in cardiac and neurologic disease. Isolated systolic hypertension is responsible for significantly higher rates of stroke than diastolic hypertension. It is also associated with higher rates of cardiac and vascular remodeling, as evidenced by increased hypertrophy of the cardiac chambers and stiffness of the blood vessels.

As systolic hypertension becomes more and more implicated in the pathogenesis of heart disease and stroke, optimal control and treatment of this often silent disease can help prevent many of the fatal complications and outcomes associated with it.

Reference:
Preventing heart disease by controlling hypertension: impact of hypertensive subtype, stage, age, and sex, American Heart Journal. 145(5):888-95

Additional Notes:
Additional references: Qureshi AI. et al. Isolated and borderline isolated systolic hypertension relative to long-term risk and type of stroke: a 20-year follow-up of the national health and nutrition survey. Stroke. 33(12):2781-8, 2002 Dec.

Pini R. Cavallini et al. Cardiovascular remodeling is greater in isolated systolic hypertension than in diastolic hypertension in older adults: the Insufficienza Cardiaca negli Anziani Residenti (ICARE) a Dicomano Study. Journal of the American College of Cardiology. 40(7):1283-9, 2002 Oct 2.