Blood pressure load--a better determinant of hypertension.

Noninvasive ambulatory blood pressure monitoring was used to evaluate the diagnosis of hypertension in 168 untreated patients with essential hypertension. On the basis of overall office blood pressure--the mean of 12 measurements, 2 in each of three positions (supine, sitting, and standing) on 2 consecutive days--133 patients were diagnosed as having hypertension (diastolic blood pressure of 90 mm Hg or higher) and 35 as having borderline hypertension (diastolic blood pressure of less than 90 mm Hg). The mean blood pressures for those with hypertension and borderline hypertension were 149/99 and 135/87 mm Hg, respectively. The mean ambulatory diastolic blood pressure was 90 mm Hg or higher in 123 patients during awake hours and in 91 patients during 24 hours. The diastolic blood pressure loads (percentage of ambulatory diastolic blood pressures more than 90 mm Hg) in patients with hypertension and borderline hypertension, respectively, were 69% and 43% during awake hours and 59% and 35% during 24 hours. The systolic blood pressure loads (percentage of systolic readings more than 140 mm Hg) during awake and 24 hours were 56% and 48%, respectively, in patients with established hypertension and 31% and 26%, respectively, in those with borderline hypertension. Thus, ambulatory blood pressure monitoring and blood pressure load provide useful information for diagnosing hypertension.