The importance of diastolic blood pressure in predicting cardiovascular risk.

Brachial systolic blood pressure (SBP) is the overall best predictor of future cardiovascular risk for the entire hypertensive population; however, there is much that can be learned from assessing diastolic blood pressure (DBP) in relation to simultaneous levels of SBP, because the former is not distorted by pressure amplification. Low DBP in very young adults (mean age 20 years), presenting as isolated systolic hypertension (ISH), results from elevation in stroke volume and/or arterial stiffness. This subtype of hypertension has a marked male predominance, occurs twice as frequently as essential hypertension, and is potentially not a benign condition. In contrast, isolated diastolic hypertension (IDH) in young adults (mean age of 40 years) with IDH occurs predominantly in men with a high prevalence of metabolic syndrome. Indeed, persons with IDH frequently evolve into systolic-diastolic hypertension and are potentially at increased risk for future diabetes and cardiovascular complications. The older age population with ISH and low DBP (mean age >/=60 years of age) has a high prevalence of left ventricular hypertrophy, increased ventricular-arterial stiffness, and a tendency for diastolic dysfunction and heart failure. Finally, concordant very high DBP, especially in older persons, defines potential hypertensive urgencies, emergencies, secondary forms of hypertension, and other high peripheral resistance states.