Understanding the association between mean arterial pressure and mortality in young adults

Mean arterial pressure (MAP), the average blood pressure (BP) over a cardiac cycle, is an important measurement of the overall circulating pressure load. Adequate MAP (at least 60 mm Hg) is needed to sustain sufficient perfusion pressure for tissue perfusion so as to reduce hypoperfusion and organ failure, furthermore, prevent death.1 MAP is highly associated with systolic BP (SBP) and diastolic BP (DBP). Previous studies have confirmed MAP as an important independent predictor of metabolic syndrome, cardiovascular disease (CVD) and cardiovascular death.2–7 However, unlike the well-established strong association between MAP and cardiovascular mortality,4–6 the evidence on the predictive utility of MAP in the risk of all-cause death remains controversial. MAP was found to be comparable to SBP in predicting the risk of CVD mortality and all-cause mortality across all age and gender groups in the Chicago Heart Association cohorts,6 while every 10 mm Hg increase in MAP was reported to be independently associated with a 14% increase in the risk of all-cause mortality in the elderly with isolated systolic hypertension in the USA.7 However, in Middle Eastern populations without baseline CVD and antihypertensive medications, MAP showed insignificant relation with all-cause mortality among the elderly, although it was strongly associated with an increased risk of CVD mortality and all-cause mortality in those aged <60 years.5 This evidence based on the middle-aged or elderly populations is inadequate to define the role of MAP in predicting all-cause death among the young, who are generally ‘healthy’.