The ambulatory arterial stiffness index (AASI) is a measure of the stiffness of the arterial system. Arterial stiffness shows a nonlinear relationship to distending pressure, with stiffness increasing exponentially as the distending pressure increases linearly. A high AASI indicates an increased risk for cardiovascular mortality.



(1) slope of the line through 24 hour blood pressure readings (X axis = systolic pressure, Y axis = diastolic pressure)



= 1 - SLOPE



• A slope near 0 and an AASI near 1 indicates a stiff arterial tree.

• A slope near 1 and an AASI near 0 indicates a low degree of stiffness.


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