Regional circulation through finger and calf arteries in essential hypertension

The information available on the circulation in the limbs in hypertensive patients is incomplete and partially conflicting. In the present study, circulation through calf and finger arteries was simultaneously examined in 51 patients with mild to moderate hypertension; the data were compared to a group of 23 normotensive controls. Recordings were made at rest and during application of vasodilator and vasoconstrictor stimuli. Blood flow to calf and finger arteries was significantly increased in hypertensives as compared to controls; calculated vascular resistance was markedly and significantly lower at the skin and slightly but not significantly lower at the calf. During reactive hyperemia, there was a stepwise increase in flow and decrease in resistance in both groups. However, in hypertensives, the decrease in resistance was significantly less pronounced; at the calf, it reached a level that was significantly higher compared to the level seen in controls. Handgrip and cold pressure tests caused increases in systemic blood pressure and vascular resistance that were larger in hypertensives. Similar results both for the vasodilator and vasoconstrictor responses were seen when results were expressed in absolute values or as percentage of control. Thus, in mild to moderate hypertension, there is increased flow at rest, decreased capacity to dilate, and increased responsiveness to vasoconstrictor stimuli. These data are compatible with the presence of both structural changes and/or functional abnormalities.