Fibrinolytic activity and calf pump failure.

The interstitial fibrinolytic activity of the upper and lower limbs was investigated in subjects with abnormal calf pump function by measuring the lysis rate of experimentally produced subcutaneous 125I-fibrin clots. Thirty-three subjects with healed venous ulcers, five with varicose veins and 11 controls were studied. 125I-fibrin clots were produced in the subcutaneous tissue of the forearms and legs and clearance half-life was calculated. Calf pump function was assessed by foot volumetry and the 'gaiter' skin nutritive circulation by measuring the transcutaneous oxygen tension (PtcO2). Fibrin clearance was prolonged from the subcutaneous tissues of the legs of subjects with varicose veins and healed ulcers compared with controls. Negative correlations were found between fibrin clearance half-life and the half-volume refilling time (P less than 0.01) and the PtcO2 (P less than 0.01).