Purpose of review: Heparin-induced thrombocytopenia (HIT) is a prothrombotic complication of heparin therapy caused by antibodies against platelet factor 4/heparin complexes. Progress in our understanding of HIT has translated to improvements in treatment and patient outcomes. The objective of this review is to examine recent advances and highlight areas of future inquiry in the epidemiology, diagnosis, and management of this potentially fatal disorder.
Recent findings: Risk factors for the development of HIT related to heparin administration are well described. Recent identification of host-related risk factors adds to our understanding of disease epidemiology. The limited specificity of clinical diagnosis and widely used immunologic assays for HIT results in frequent overdiagnosis. Novel clinical decision rules and laboratory assays to improve diagnosis are in development. Fondaparinux, bivalirudin, and desirudin have recently been added to the HIT armamentarium.
Summary: Despite these advances, critical issues remain to be addressed. Future research efforts will focus on the identification of novel clinical risk factors and biomarkers that will enable recognition of individuals at greatest risk, optimization of diagnostic strategies and use of currently available therapeutics, and development of new drugs that not only reduce thrombotic complications, but also minimize bleeding risk, are well tolerated in patients with organ dysfunction, and facilitate transition to outpatient therapy.