Role of Arteries in Peripheral Resistance of Hypertension

Abstract

It seems established that arterial hypertension must be due to an increased peripheral resistance, but which part of the vascular bed is concerned in this increase is still somewhat uncertain. Evidence on the whole supports the view that it is due to arteriolar constriction, but some workers believe that the larger arteries also become narrowed in hypertensive conditions. 1

Our observations represent an attempt to ascertain whether or not the larger arteries are involved in the production of the increased resistance of chronic hypertension. It is known that normally the blood pressure in the arterial bed falls gradually from large to small arteries, and that the greatest fall occurs in the region of the arter-ioles. If the arteriolar resistance should increase, the arterial blood pressure would be increased throughout, in small as well as large arteries, so that the pressure gradient from large to small arteries would either remain substantially unchanged, or become less. If an increased resistance should occur in the arteries themselves, the pressure gradient would tend to become steeper, since the pressure would be raised in the largest arteries, but would be reduced in the smallest.

We therefore measured the blood pressure in a large and a small artery of subjects with hypertension, and compared the figures with those obtained from individuals having normal systolic pressures. Blood pressure was determined in the brachial artery by the usual auscultatory method, and in the digital artery by Gaertner's method, 2 whereby, after rendering the ringer bloodless, the pressure is noted at which the finger again becomes suffused with blood. This pressure is assumed to be the systolic pressure in the digital artery.

From Table I it will be seen that the average brachial to digital pressure gradient in cases of hypertension shows no significant difference from that in subjects with normal or with low blood pressure.