Platelet Count Trends and Prevalence of Heparin-Induced Thrombocytopenia in a Cohort of Extracorporeal Membrane Oxygenator Patients.

Abstract

To assess the prevalence of heparin-induced thrombocytopenia and to study platelet count trends potentially suggestive of heparin-induced thrombocytopenia in a population of extracorporeal membrane oxygenator patients. Retrospective cohort study. A total of 926-bed teaching hospital. Extracorporeal membrane oxygenator patients who survived longer than 48 hours from extracorporeal membrane oxygenator initiation between January 1, 2009, and December 31, 2013. None. Demographic and clinical data were collected prospectively on all extracorporeal membrane oxygenator patients. Heparin-induced thrombocytopenia testing results and platelet count variables were obtained from the electronic medical record. We used our institutional algorithm to interpret the results of heparin-induced thrombocytopenia testing. Ninety-six extracorporeal membrane oxygenator patients met the inclusion criteria. Eight patients met the algorithm criteria for heparin-induced thrombocytopenia diagnosis and seven of those had documented thromboembolic event while on extracorporeal membrane oxygenator (prevalence of heparin-induced thrombocytopenia and heparin-induced thrombocytopenia related thrombosis, 8.3 and 7.3, respectively). Heparin-induced thrombocytopenia positive patients were younger; all underwent venoarterial extracorporeal membrane oxygenator; spent more hours on extracorporeal membrane oxygenator; had significantly higher heparin-induced thrombocytopenia enzyme-linked immunosorbent assays optical density; had a higher prevalence of thromboembolic events and reached platelet count nadir later. There was no difference in mortality between heparin-induced thrombocytopenia positive and negative patients. Comparison of platelet count trends revealed that there was no statistically significant difference between the predefined study groups. Prevalence of heparin-induced thrombocytopenia and heparin-induced thrombocytopenia-related thrombosis among extracorporeal membrane oxygenator patients at our institution is relatively high. Using platelet count trends to guide decision to test for heparin-induced thrombocytopenia is not an optimal strategy in extracorporeal membrane oxygenator patients. Without a validated pretest probability clinical score, serosurveillance in a defined high-risk group of extracorporeal membrane oxygenator patients may be needed.