Immunohistochemical evaluation of failed vessel anastomoses in clinical microsurgery

Failed vessel anastomoses collected from 12 patients during elective free flap surgery, and from one patient after failed mid-hand replantation were subjected to immunohistochemical analysis. The anastomotic failure was due to an obvious thrombosis, poor flow, an excessively sharp pulse or some other reason causing a non-functioning anastomosis. A total of 17 samples were obtained, 13 of them arterial, three between the artery and vein graft, and one venous. The majority of samples were resected during primary surgery and four of them at reoperation. Variables of coagulation and fibrinolysis were analysed repeatedly during the operation in 7/13 patients. Total occlusion was seen in 6/17 samples and a non-occlusive thrombus in 4/17; two of these were due to suture error. Immunohistochemistry showed that, overall, the endothelial cells (PECAM-l, CD 31) were absent and that the staining pattern for platelets (CD 42b and CD 31) and fibrin (fibrin II, T2G1) correlated. In the absence of a thrombus, however, adherent platelets were positive only for CD 42b, not for PECAM-1. Vessel inflammation was a prominent feature at reoperations. Analysis of coagulation and fibrinolytic markers (thrombin–antithrombin III complex, prothrombin fragment 1 + 2 and D-dimer) confirmed the occurrence of thrombosis in three patients undergoing breast reconstruction with clinically obvious thrombosis during primary surgery or at reoperation. Moreover, the patients with active cancer (2/7) were clearly hypercoagulable compared with the other patients. In short, the primary anastomotic failure was associated with loss of endothelial cells, and with co-localised platelet recruitment and fibrin formation at these sites. At reoperation, inflammation was a prominent feature at the vessel site of thrombi.