(479) Association of Mean Platelet Volume With Bleeding and Clotting Risks on ECMO

Introduction: Bleeding and clotting are associated with a substantial mortality risk in Extracorporeal Membrane Oxygenation (ECMO) patients. Often, platelets are transfused to prevent bleeding. However, an important knowledge gap exists in predicting bleeding and clotting risk. Adding a readily available platelet marker, such as mean platelet volume (MPV), might better categorize the risk of bleeding and clotting. We aim to assess the MPV ability to predict bleeding or clotting risk on the following day in ECMO patients.

Methods: We retrospectively studied children and adults admitted to neonatal, pediatric, and adult ICUs at 2 ECMO centers from 2018-2022, who were on ECMO support and required platelet transfusions. We excluded patients with congenital bleeding, thrombotic disorder, oncological diagnosis, recent chemo/radiotherapy, pregnant or postpartum. Eligible patients were identified in the electronic medical records using CPT/ICD-10 codes and the ECMO registry. We collected demographics, ECMO, laboratory, intervention, and outcome variables. The association between pre-transfusion MPV and bleeding or clotting on subsequent day was assessed with day-level univariable and multivariable logistic regression models.

Results: A total of 405 patients were enrolled (82% VA ECMO and 18% VV ECMO), 65% male, with a median age of 51 years (IQR 7;67). Among them, 17% were less than 1 year, and 12% were between 1 and 18 years. The ECMO indications were cariogenic shock (63%), respiratory failure (25%), ECPR (8%), and septic shock (4%). The median (IQR) pre-platelet transfusion laboratory values include platelet count 55x109/L (39;80), MPV 11.2 fL (10.5;12.0), aPTT 44 sec (35;64), PT 13 sec (12;16), and Fibrinogen 263 mg/dL (192;379). Subsequent-day bleeding and thrombosis occurred after 18% and 4% of platelet transfusion, respectively. Factors associated with bleeding were low MPV (p=0.006) and fibrinogen (p < 0.001), but not platelet count (p=0.32). Factors associated with thrombosis were low aPTT (p=0.005). 44% of patients survived hospital discharge.

Conclusions: A lower MPV among ECMO patients was associated with increased bleeding risk the following day, independent of the platelet count. However, neither MPV nor platelet count were associated with increased clotting risk.