Factor XIIIA and clot strength after cardiopulmonary bypass

Reduced factor XIIIA levels and decreased clot strength have been associate d with increased bleeding after cardiopulmonary bypass (CPB). The purpose o f this study was to evaluate the relationship between hemostatic factors, i ncluding factor XIIIA, and clot strength before, during and after CPB. Fact or XIIIA antigen, platelet counts, fibrinogen, factor V activity, tissue pl asminogen activator and clot strength (by thromboelastograph) were measured at baseline, after 45 min of CPB, at the end of CPB and 4 h post-operative ly in 34 patients. Baseline factor XIIIA antigen was 5.2 +/- 1.4 mg/l. On a verage, factor XIIIA levels dropped to 64% and clot strength to 77% of base line values after 45 min on CPB and remained below baseline during the imme diate post-operative period. Clot strength was significantly correlated (r = 0.81) with platelet count and fibrinogen but not plasma factor XIIIA leve ls. Addition of 10 mg/l recombinant factor XIII{a(2)} significantly increas ed clot strength. Postoperative bleeding at 2 h was inversely correlated wi th platelet count, factor XIIIA antigen and dot strength measured at the en d of CPB. Maintenance of adequate platelet counts and factor XIIIA levels a t the end of CPB may play a role in maintaining clot strength and reducing blood loss. (C) 2001 Lippincott Williams & Wilkins.