Skeletal muscle capillaries in intermittent claudication.

The ultrastructural dimensions and density of capillaries in 23 gastrocnemius or rectus femoris muscles in patients with intermittent claudication due to arteriosclerosis obliterans (ASO) were studied. Constant ultrastructural alterations that were not seen in the control patients were thickening, replication, and remnants of the capillary basement membrane (BM). Compared with the control patientes, the percentual area of the BM was significantly larger (P less than .01), the lumen was significantly smaller (P less than .01), and the ratio of capillaries to muscle fiber was significantly higher (P less than .01) in patients with ASO. These changes were probably due to ASO since they increased with growing severity of claudication.