Hemodynamics of Large and Small Vessels in Peripheral Vascular Disease

To evaluate the hemodynamics of large and small vessels in patients with complete arterial occlusion and patients with vasospasm, digital flow, digital pulse contour, small-vessel resistance, flow-to-pulse ratio, large-vessel pressure drop, pulse velocity, and distensibility were compared to values found in normal subjects.[see figure in the PDF file]In the normal subject following orally administered alcohol, small-vessel resistance decreased but large-artery pressure drop, pulse velocity, and distensibility of the capacity vessels were not altered significantly.In arterial occlusive disease, small-vessel resistance was essentially normal in the absence of small-vessel occlusion; a high large-artery pressure drop, rounded pulse contour, and decreased pulse amplitude were observed. These are interpreted as being due to the damping effect of the narrowed, elongated collateral flow pathway that develops around the site of the occlusion. Pulse velocity also was decreased whereas flow-to-pulse ratio was increased in patients with occlusive disease. Large-vessel hemodynamics were unchanged after alcohol, suggesting lack of effect of the dilator on the collateral vessels.In vasospasm there was evidence of increased large-artery and small-vessel resistance and decreased distensibility of the capacity vessels, all of which returned toward but not completely to normal following alcohol.Digital pulse amplitude was found not to correlate well with flow, particularly in patients with arterial occlusive disease.