Heparin-induced thrombocytopenia in patients with mechanical circulatory support: a systematic review and meta-analysis.

Background: Mechanical circulatory support (MCS) is increasingly being used for providing hemodynamic support in patients with advanced cardiogenic shock. Despite its benefits, it continues to carry a significantly high risk of multiple complications. The use of anticoagulation is crucial to prevent device-related and patient-related thrombosis in MCS-treated patients. Heparin use is complicated by the risk of heparin-induced thrombocytopenia (HIT). Objectives: We sought to describe the incidence and outcomes of HIT in patients with MCS. Methods: We performed a systematic search in Embase and Medline and included all studies reporting the incidence of HIT in cohorts of patients who underwent placement of MCS. Case series and case reports and studies describing the incidence of HIT in patients with extracorporeal membrane oxygenation were excluded. Data were pooled in a single-arm, proportion meta-analysis for each outcome (incidence of HIT, rate of thrombotic events, and overall mortality). Results: We screened 438 studies, and 17 met inclusion criteria. We found an overall incidence rate of HIT of 7% among patients receiving MCS, and when assessing the incidence rate based on MCS device, the rate was 6% for Impella, 8% for left-ventricular assist device, and 7% for intra-aortic balloon pump. Furthermore, the incidence rate of thrombotic events was 42%. The rate of bleeding complications was reported only in 1 study. The mortality rate among HIT cases while on MCS was 41%. Conclusion: Patients who are managed with MCS are at high risk of HIT, which results in significant morbidity and mortality.