Objective: Although current guidelines rest exclusively on the measurement of systolic and diastolic blood pressures, the arterial pressure wave is more precisely described as consisting of a pulsatile (pulse pressure) and a steady (mean pressure) component. This study explored the independent roles of pulse pressure and mean pressure as predictors of mortality in a wide range of patients with hypertension.
Design and methods: This meta-analysis, based on individual patient data, has combined results from the control groups of seven randomized clinical trials conducted in patients with systolo-diastolic or isolated systolic hypertension. The relative hazard rates associated with pulse pressure and mean pressure were calculated using Cox's proportional hazard regression models with stratification for the seven trials and with adjustment for sex, age, smoking and the other pressure.
Results: A 10 mmHg wider pulse pressure at baseline, which corresponds to approximately one-half of its standard deviation, was independently associated with an increase in risk by 6% for total mortality (P = 0.001), 7% for cardiovascular mortality (P = 0.01), and 7% for fatal coronary accidents (P = 0.03). The corresponding increase in risk of fatal stroke was similar (+6%, P = 0.27) but there were too few strokes to reach statistical significance. In similar analyses, mean pressure was not identified as an independent predictor of these outcomes. Significant interactions of pulse pressure or mean pressure with age suggested that the prognostic power of pulse pressure for fatal stroke was more important at higher age (P = 0.04), whereas the prognostic power of mean pressure for coronary mortality was greatest in the young (P = 0.01).
Conclusions: In hypertensive patients pulse pressure, not mean pressure, is associated with an increased risk of fatal events. This appears to be true in a broad range of patients with hypertension.