Pericapillary fibrin cuffs in venous ulceration. Persistence with treatment and during ulcer healing.

A recent hypothesis suggests that venous hypertension leads to ulceration through the formation of pericapillary fibrin cuffs, which are presumed to impede the exchange of oxygen and other nutrients. In this report, we evaluated by direct immunofluorescence the presence of pericapillary fibrin at the edge of venous ulcers during the course of treatment with elastic compression. In an initial group of 23 patients studied at baseline, pericapillary fibrin cuffs were detected in 20 (91%) of 22 patients. The intensity of fibrin staining, rated blindly on a scale of 0 to 3, could not be correlated with several baseline parameters, including the clinical presence and extent of lipodermatosclerosis, ulcer size, venous recovery time, and transcutaneous oxygen measurements (TcPO2) taken next to the ulcer. Eleven of this initial group of 23 patients were randomly selected to receive elastic compression treatment, and were evaluated for the persistence of pericapillary fibrin at 60 and 120 days. Although a reduction (mean +/- SD = 50.2% +/- 25.7) in ulcer size occurred in 10 of the 11 patients, pericapillary fibrin was still present at the ulcer edge and with undiminished intensity. We conclude that pericapillary fibrin cuffs in venous ulcers persist with compression treatment and in spite of healing, and are unlikely to be directly related to the development of ulceration.