Effects of arterial dilator agents on central aortic systolic pressure and on left ventricular hydraulic load.

Recordings of pressure in the brachial or peripheral arteries fail to disclose the marked increase in systolic pressure that occurs in the proximal aorta and central arteries with increasing age and with hypertension. This systolic pressure boost is caused by wave reflection returning from the periphery of the body while the ventricle is still contracting. Such early wave reflection is caused in turn by increased pulse-wave velocity, attributable to stiffening of the aorta and major conduit arteries. Drugs have little effect on arterial stiffening, whereas wave reflection can be markedly reduced by agents that dilate peripheral arteries. Such reduction in wave reflection causes substantial decrease of systolic pressure in central arteries. Because of differential timing of wave reflection, however, such reduction is not apparent from pressure recordings taken in the brachial or other peripheral arteries. The sphygmomanometer, therefore, fails to show the favorable effects of reduced wave reflection in the proximal aorta and central arteries. Noninvasive tonometric pressure wave recordings can supplement the sphygmomanometer to assess the magnitude of beneficial effect.