Differentiating biochemical from clinical heparin resistance in COVID-19

Excerpt

With interest, we read the recent paper by White and coworkers in which heparin resistance in patients with COVID-19 patients on the intensive care unit was described [1]. Accumulating evidence shows that patients with COVID-19 are at high risk for thrombotic events, even those that receive normal to increased doses of thromboprophylaxis with low molecular weight heparin or unfractionated heparin [2, 3]. The observation that thromboprophylaxis doesn’t prevent thrombotic events in a proportion of patients suggests that thromboprophylactic heparins insufficiently downregulate coagulation. White et al. demonstrate a failure to achieve heparin target levels as measured by APTT or anti-Xa assays. In addition, spiking of patient plasma with LMWH led to a lower than expected anti-Xa levels in plasma. These observations led the authors to conclude COVID-19 patients are heparin resistant. …