Pulsatile flow and pressure in human systemic arteries. Studies in man and in a multibranched model of the human systemic arterial tree.

Abstract

Mechanisms responsible for the contour of pressure and flow waves and the pattern of vascular impedance in human systemic arteries were studied. Pulsatile pressure and flow were recorded from the ascending aorta of 7 patients undergoing open heart surgery and from the ascending aorta and other arteries of 17 patients at diagnostic catheterization. Ascending aortic pressure/flow relationships in the 7 surgical patients were expressed as input impedance to the systemic circulation. Pressure and flow wave contour and impedance results were interpreted with the aid of a multibranched model of the systemic arterial tree, whose parameters could be manipulated to simulate different physiological and pathological conditions. Data on pressure and flow waves and their relationship in human subjects could be explained on the basis of 2 reflecting sites in the systemic circulation.sbd.one representing the resultant of all arterial terminations in the upper part of the body, and the other, some 1.5 times further away, the resultant of all arterial terminations in the lower body. The concept of the arterial system as an asymmetric T tube with 2 discrete ends was advanced previously to explain the main features of pressure and low waves and their relationship in different experimental animals. This concept appears equally applicable to human subjects.