Abstract 3321: Gender Impacts Capillary Density and Skeletal Muscle Composition in Patients With Peripheral Arterial Disease

Background : Peripheral arterial disease (PAD) is a disorder characterized by impaired blood flow to the legs and maladaptive changes in the skeletal muscle. It is generally accepted that the skeletal muscle characteristics in patients with PAD include decreased capillary density and an altered percentage of oxidative myofibers. The scientific literature is conflicting, and it is based on studies with small sample size and older methodologies of skeletal muscle analysis. In addition, women are under-represented or not included at all in these studies. Hypothesis : We hypothesized that there would be differences in skeletal muscle composition in PAD patients compared to healthy controls. We further hypothesized that there would be gender differences in skeletal muscle composition in PAD patients versus healthy controls. Methods : Thirty -one patients with PAD and 31 age-, gender-, and activity-matched healthy controls underwent gastrocnemius muscle biopsy. Capillary density analysis and muscle fiber type determination were performed using immunohistochemistry techniques. Capillary density was measured as endothelial cells per muscle fiber and endothelial cells per area (mm 2 ). Results : There was no significant difference in capillary density in patients with PAD versus healthy controls when measured as endothelial cells per fiber (mean = 1.45 ± 0.43 vs. 1.50 ± 0.35, NS) or area (mean = 1.20 ± 0.29 vs. 1.29 ± 0.33, NS). There was also no difference in muscle fiber type composition between the groups. In the PAD cohort, capillary density was significantly lower in the men versus the women (mean = 1.36 ± 0.35 vs. 1.59 ± 0.51, p=0.005). In our cohort of women, there was no difference in capillary density in patients with PAD versus healthy controls (N=12). In men, capillary density was significantly lower in the PAD group versus healthy controls (N=19, mean = 1.09 ± 0.20 vs. 1.28 ± 0.34, p=0.043). Conclusions : Our data fail to confirm the belief that patients with PAD have a decreased capillary density and an altered percentage of oxidative myofibers. However, we did find that gender has an important impact on these characteristics. Further study of skeletal muscle composition in PAD may help to better understand the functional relevance of the gender differences.