Heparin-Induced Thrombocytopenia in Contemporary Cardiac Surgical Practice and Experience With a Protocol for Early Identification.

This analysis was designed to (1) examine the impact of heparin-induced thrombocytopenia (HIT) on contemporary cardiac surgical practice and (2) describe the results of a protocol designed for early identification of the presence of the immune mechanisms involved. Consecutive patients who underwent cardiac surgery were screened postoperatively for thrombocytopenia. Patients with thrombocytopenia were tested for antiplatelet factor 4 (PF4)/heparin antibodies by ELISA and clinical evidence of thrombosis sought. Demographics, co-morbidities, operative details, and outcomes were abstracted from the departmental registry. Of 14,415 consecutive patients undergoing cardiac surgery, 1,849 patients (13%) had thrombocytopenia. Of them, 277 patients (15%) had PF4/heparin antibodies and 76 patients (4%) had both antibodies and clinical thrombosis. Antibodies were more frequent: (1) in women (p = 0.01), (2) in patients with an increased body mass index (p <0.01), and (3) in patients with clinical heart failure before surgery (p <0.01). Thirty-day mortality was greatest among the 76 patients with the triad of thrombocytopenia, antibodies, and clinical thrombosis (30%). Of the 1,849 patients with thrombocytopenia, the presence of PF4/heparin antibodies was an independent predictor of 30-day mortality (odds ratio 2.09, 95% CI 1.46 to 2.49; p <0.001). HIT remains an infrequent but very serious complication of heparin therapy in contemporary cardiac surgical practice. The possibility that the presence of HIT antibodies in patients with thrombocytopenia independently increases operative mortality deserves further study.

Ten-year screening for thrombocytopenia after aortic valve replacement.

OBJECTIVES: Thrombocytopenia is very common after cardiac surgery, but rarely studied systematically. Heparin-induced thrombocytopenia has been studied extensively, but the diagnosis remains clouded by the lack of sensitivity and specificity of laboratory tests. It remains unknown whether a local initiative of screening program has been successful in the management of postoperative thrombocytopenia. METHODS: We have implemented a screening protocol since 2002. Cardiac surgery patients were postoperatively screened for thrombocytopenia. Thrombocytopenia was stratified by the anti-platelet factor 4/heparin antibody (enzyme-immune assay, Elisa) test. The presence of clinical embolithrombosis was sought in patients with antibodies. Preoperative and operative characteristics and outcomes were obtained from the departmental registry of cardiac surgical procedures. RESULTS: A total of 16 529 patients were screened for thrombocytopenia from January 2003 to 2012. One thousand two hundred and sixty-one patients undergoing isolated aortic valve replacement (AVR) were included in this study. The overall incidence of thrombocytopenia after AVR was 26.8%. Elisa (+) occurred in 43 of the 1261 patients (3.4%), Elisa (+) plus thrombosis occurred in 14 (1.1%) and in 32.6% of Elisa (+) patients. Age and preoperative lower platelet count were independent predictors of thrombocytopenia. Elisa (+) alone was associated with increased operative mortality, stroke and bleeding. Patients developed thrombocytopenia and Elisa (+) were more likely to receive bioprosthetic valves. CONCLUSIONS: Thrombocytopenia and Elisa (+) are more common after AVR than after other procedures, and both were associated with increased adverse clinical outcomes. Age and lower preoperative platelet count were associated with postoperative thrombocytopenia and Elisa (+).