Large vessel impedance in peripheral atherosclerosis.

Recent studies based on an animal model of arterial stenosis have shown that large vessel impedance (ZL), determined from the high-frequency vascular hydraulic impedance of a stenotic femoral arterial bed, is linearly related to the large vessel stenotic resistance, and somewhat independent of distal (small vessel) arteriolar resistance. To determine the applicability of these findings on human subjects with stenotic atherosclerotic lesions, ZL was determined in the femoral arteries of 17 patients (at the time of reconstructive operations) with no (N), mild (AS), and severe (occlusive) atherosclerotic (ASO) disease, and in a group of patients before and after femoral-to-popliteal bypass procedures (FEM-POP). Data were collected under steady-state conditions (SS) and during peak flow after a 30 mg bolus intra-arterial administration of papaverine hydrochloride (PAPAV). The ZL was found to be significantly greater (P less than 0.05) for the ASO group than for the N group at SS and after PAPAV administration. There was no significant difference in ZL between the SS and PAPAV conditions for all groups. The ZL decreased significantly (P less than 0.01) from the pre- to post-bypass conditions (with and without the stenosis), at steady-state and after papaverine hydrochloride administration. Large vessel impedance appears to provide a reliable index of the severity of a large vessel atherosclerotic stenosis, and is indpendent of small vessel resistance in humans. These findings are consistent with those of previous experimental animal studies.