Central blood pressure as an index of antihypertensive control: determinants and potential value

The measurement of central blood pressure has generated interest as a tool in predicting cardiovascular events. The purpose of this article is to review the meaning and measurement of the central blood pressure and consider its potential value as an index of the antihypertensive response. Indirect estimation of central aortic pressures is obtained by the study of the radial pulse wave compared with a central pulse wave contour measured at the carotid or femoral artery level. The sum of the forward pressure wave created by ventricular contraction and of the reflected pressure wave from the peripheral arterial system produce the peak systolic blood pressure in the aorta. Measurement of the peripheral reflected-wave contribution to aortic blood pressure can be quantified as the augmentation index. Also, the increase in the rapidity of this travelling wave can be measured as the pulse wave velocity. These 2 parameters are considered to be valid indices of the peripheral arterial stiffness. Along with the calculation of systolic and diastolic aortic pressures, these measurements can give a better understanding of the actual central blood pressure to which core organs like heart, brain, and kidneys are submitted. There is tantalizing evidence for the potential value of central blood pressure as a useful index of antihypertensive action, but until clear evidence is obtained, its use should continue to be considered exploratory.