The Relative Early Decrease in Platelet Count Is Associated With Mortality in Post-cardiotomy Patients Undergoing Venoarterial Extracorporeal Membrane Oxygenation

Background: The relationship between the magnitude of platelet count decrease and mortality in post-cardiotomy cardiogenic shock (PCS) patients undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO) has not been well-reported. This study was designed to evaluate the association between the relative decrease in platelet count (Rel Delta platelet) at day 1 from VA-ECMO initiation and in-hospital mortality in PCS patients. Methods: Patients (n = 178) who received VA-ECMO for refractory PCS between January 2016 and December 2018 at the Beijing Anzhen Hospital were reviewed retrospectively. Multivariable logistic regression analyses were performed to assess the association between Rel Delta platelet and in-hospital mortality. Results: One hundred and sixteen patients (65%) were weaned from VA-ECMO, and 84 patients (47%) survived to hospital discharge. The median [interquartile range (IQR)] time on VA-ECMO support was 5 (3-6) days. The median (IQR) Rel Delta platelet was 41% (26-59%). Patients with a Rel Delta platelet >= 50% had an increased mortality compared to those with a Rel Delta platelet < 50% (57 vs. 37%; p < 0.001). A large Rel Delta platelet (>= 50%) was independently associated with in-hospital mortality after controlling for potential confounders (OR 8.93; 95% CI 4.22-18.89; p < 0.001). The area under the receiver operating characteristic curve for Rel Delta platelet was 0.78 (95% CI, 0.71-0.85), which was better than that of platelet count at day 1 (0.69; 95% CI, 0.61-0.77). Conclusions: In patients receiving VA-ECMO for post-cardiotomy cardiogenic shock, a large relative decrease in platelet count in the first day after ECMO initiation is independently associated with an increased in-hospital mortality.