Utility of D-dimers in COVID-19 Patients Requiring Extracorporeal Membrane Oxygenation

A retrospective study was performed examining the trend of inflammatory markers, including D-dimers, in 29 COVID-19 patients requiring veno-venous (VV) extracorporeal membrane oxygenation (ECMO) support. We observed that COVID-19 patients with pre-cannulation D-dimer levels >3,000 ng/mL had a significantly shorter time from admission to cannulation (4.78 vs. 8.44 days, p = 0.049) compared to those with D-dimer <3,000 ng/mL. Furthermore, patients with D-dimer >3,000 ng/mL had a trend of lower pH (7.24 vs. 7.33), higher pCO(2) (61.33 vs. 50.69), and higher vasoactive inotropic score (7.23 vs. 3.97) at time of cannulation, however, these were not statistically significant. This cohort of patients also required a longer duration of ECMO support (51.44 vs. 31.25 days). However, 13 patients required at least one ECMO-circuit exchange and 16 patients did not require any exchanges. There was a consistent drop in D-dimer values after every circuit exchange, which was not observed in any of the other examined inflammatory markers, including ferritin, lactate dehydrogenase, or C-reactive protein. We propose that elevated D-dimer levels (>3,000 ng/mL) reflect increased disease severity in COVID-19, and predict a longer ECMO course. Once on ECMO, however, the D-Dimer level consistently decreased with every circuit exchange, which may reflect thrombus within the oxygenator rather than just disease severity.