Abstract TP484: Superficial Femoral Artery Atrophy and Reduced Lower Limb Blood Flow in Subacute Stroke Survivors

Abstract

Introduction: Femoral artery atrophy and reduced endothelial function in the peripheral arteries of the affected lower limb contribute to reduced hyperemic blood flow in response to muscle contractions in chronic stroke survivors. These impairments could contribute to increased muscle weakness and exacerbate neuromuscular fatigue in stroke survivors. The time-course of these changes to the peripheral vasculature post-stroke have not been examined. Hypothesis: Superficial femoral artery atrophy and reduced blood flow to the affected limb occur in the subacute stroke period. Methods: This was a prospective, observational study which enrolled subacute stroke survivors admitted to inpatient rehabilitation at a single site. Maximum voluntary contractions (MVCs) of the paretic and non-paretic knee extensor muscles were assessed using a Biodex dynamometer. The superficial femoral artery was imaged in both legs using ultrasonography and arterial diameter was measured off-line with Brachial Analyzer software. Superficial femoral artery resting and hyperemic blood flow following MVCs was also quantified using ultrasonography. Results: Twelve subacute stroke survivors were enrolled in this study (7 men, 5 women). The mean age of all study participants was 65±10 years and the mean time since stroke was 12±6 days. Superficial femoral artery diameter was smaller in the affected leg compared to the non-affected leg (5.9±0.9 mm vs. 6.3±0.9 mm, respectively; p=0.006 paired t-test). Resting blood flow to the affected leg was also lower compared to the non-affected leg (164±68 ml/min vs. 205±105 ml/min, respectively; p=0.031 paired t-test). The MVC of the knee extensor muscles of the affected leg was less than the non-affected leg (103±63 Nm vs. 152±58 Nm, respectively; p=0.027, Wilcoxon signed rank test) and hyperemic blood flow was also reduced in the affected limb (248±94 ml/min vs. 428±203 ml/min, respectively; p<0.001, Wilcoxon signed rank test). There was a positive correlation between hyperemic blood flow (fold change from rest) and MVC in the affected leg (r 2 =0.47, p=0.014). Conclusions: Superficial femoral artery atrophy and reduced limb blood flow occur in stroke survivors in the first weeks post-stroke and may contribute to limb weakness.