Ambulatory Blood Pressure Measurement

Abstract

One of the consequences of hypertension is increasing stiffness of the arteries, which leads to cardiovascular events and increased mortality.1 Clearly this process is a continuous one and, contrary to acceptance that such change is inevitable, it is not now unreasonable to assume that if stiffening in the arterial system could be detected at an early rather than at a late stage, therapeutic interventions might be initiated to delay or even prevent its occurrence. However, measuring arterial stiffness requires special equipment and trained staff, facilities that are not generally available and that are, moreover, costly. It has been proposed recently that a measure of arterial stiffness could be obtained from the routine use of ambulatory blood pressure measurement (ABPM) by using the dynamic relationship between diastolic and systolic blood pressure over 24 hours, calculated as 1 minus the regression slope of diastolic on systolic blood pressure. The rationale underlying the ambulatory arterial stiffness index (AASI) is that average distending pressure varies during the day and that the relation between diastolic and systolic blood pressure, with this changing distending pressure, depends largely on the structural and functional characteristics of the large arteries. In the Dublin Outcome Study, AASI predicted cardiovascular mortality in a large cohort of hypertensive individuals. Moreover, this prediction withstood additional adjustment for other risk factors, including pulse pressure. Interestingly, AASI was a stronger predictor of fatal …