Measuring hypertensive cardiovascular risk: the vascular overload concept.

Hypertensive cardiovascular risk may be related primarily to vascular overload, the sum of three vascular abnormalities: increased arteriolar resistance, increased large-artery stiffness, and the effect of increased early pulse-wave reflection. A method for quantifying vascular overload as an index can be derived from measurements of mean arterial pressure and pulse pressure. Several lines of evidence support the hypothesis that abnormal artery stiffness and early pulse-wave reflection become larger components of vascular overload as the duration and severity of hypertension increase. Moreover, these studies suggest that vascular overload is a true indicator of hypertensive cardiovascular risk. Increased systolic blood pressure is a surrogate for vascular overload in young and middle-aged hypertensive subjects. Increased pulse pressure and decreased diastolic pressure are superior to increased systolic pressure as surrogates for vascular overload in geriatric isolated systolic hypertension. By itself, diastolic blood pressure is difficult to interpret and may be an epiphenomenon. Therefore new therapeutic goals, are control of systolic pressure in the young and of pulse pressure in the elderly.