Protein C and protein S plasma levels in patients with lipodermatosclerosis and venous ulceration

Lipodermatosclerosis of the lower extremity, with or without ulceration, is a common manifestation of severe venous disease and the result of sustained venous hypertension. The latter is generally a sequela of deep vein thrombosis. Factors that enhance clot formation or impair fibrinolysis contribute to the pathogenesis of venous disease. It is already established that faulty fibrinolysis may play a pathogenic role in patients with venous disease. We examined the possibility that patients with venous disease have abnormally low plasma levels of proteins C and S, two proteins whose deficiencies have been reported to cause an increased frequency of thromboembolic disease. Using immunologic and functional assays for plasma proteins C and S, we found that 4 (21%) of 19 patients with lipodermatosclerosis and leg ulcers had abnormally low levels of protein C or protein S. One of 7 patients with lipodermatosclerosis without ulceration had a profoundly depressed level of protein C and a history of cerebral stroke at a young age. Plasma levels of protein C were normal in five patients with arterial insufficiency severe enough to cause leg ulceration. We conclude that abnormally low plasma levels of proteins C and S may be found in patients with lipodermatosclerosis and venous ulceration. As with the abnormally low fibrinolytic activity in these patients, our findings indicate a possible propensity for increased thrombotic disease.