Abstract
BLOOD PRESSURE (BP) is an important predictor of future cardiovascular risk. Until the technique to measure diastolic BP was introduced by Korotkoff,1 systolic BP readings (obtained by the Riva-Rocci sphygmomanometer and similar apparatuses) were the only data available, but these were sufficient to convince astute observers that BP measurements were important in predicting prognosis.2 In the 1960s and 1970s, difficulties with reproducibility and accuracy of systolic BP measurements (compared with diastolic readings) led authorities to classify hypertension using the diastolic BP.3 This occurred despite evidence from insurance companies and others with an interest in assessing the risk for cardiovascular disease that systolic BP was, at any level of diastolic BP, a strong predictor of future events.4 Since 1993, the Joint National Committee on (Prevention), Detection, Evaluation, and Treatment of High Blood Pressure5 has recognized the importance of systolic BP and made it equal to diastolic BP in the official classification of hypertension in the United States.