Delayed-onset severe heparin-induced thrombocytopenia after total arch replacement under cardiopulmonary bypass

Abstract

An extremely rare case with delayed-onset heparin-induced thrombocytopenia (HIT) is described. A 46-year-old man underwent arch replacement for aortic dissection under cardiopulmonary bypass and initial exposure of unfractionated heparin. In post operative 7 days, persistent atrial fibrillation was occurred, so a continuous infusion of heparin (10000 IU/day) and Vitamine K antagonist (Warfarin) taking was started for preventing thrombosis. By 32 days after the operation, his platelet count had fallen (3×10(3)/µL) and oral hematoma and ecchymoma of bilateral lower legs were occurred. The value of HIT antibodies and the IgG antibody was 2.485 and 1.586 on 32-postoperative day, respectively. Heparin was immediately discontinued, and argatroban administrated. Platelet exceeded above 100×10(3)/µL on 12 days of the therapy. To our knowledge, few cases of delayed-onset severe HIT associated with CPB surgery have been reported in Japan.

How We Interpret Thrombosis with Thrombocytopenia Syndrome?

“…The presence of HIT alone does not affect prothrombin time (PT), activated partial thromboplastin time (APTT), or fibrinogen level, but these test values may change due to the use of heparin or as a complication of DIC. As reflections of excessive coagulation activation and thrombus formation, levels of fibrin/fibrinogen degradation products (FDP), D-dimer and the coagulation activation marker thrombin-antithrombin complex (TAT) significantly increase [23]. Diagnosing or excluding HIT based on coagulation and fibrinolysis testing alone is difficult, necessitating an appropriate combination of the 4Ts score with immunoassays and, where possible, functional assays.…”