The Importance of Timing in Post-Cardiotomy Veno-Arterial Extracorporeal Membrane Oxygenation: a Descriptive Multicenter Observational Study

Objectives: Post-cardiotomy extracorporeal membrane oxygenation (ECMO) can be initiated intra-operatively or post-operatively based on indications, settings, patient profile and conditions. The topic of implantation timing only recently gained attention from the clinical community. We compare patients´ characteristics, in-hospital and long-term survival between intra-operative and post-operative ECMO. Methods: The retrospective, multicentre, observational Post-cardiotomy Extracorporeal Life Support (PELS-1) Study includes adults requiring ECMO due to post-cardiotomy shock between 2000 and 2020. We compare patients who received ECMO in the operating theatre (intra-operative) with those in the intensive care unit (post-operative) on in-hospital and post-discharge outcomes. Results: We studied 2003 patients [women:41.1%; median age:65 (IQR:55.0-72.0) years]. Intra-operative (n=1287), compared to post-operative (n=716), ECMO patients had worse pre-operative risk profiles. Cardiogenic shock (45.3%), right ventricular failure (15.9%), and cardiac arrest (14.3%) were the main indications for post-operative ECMO initiation, with cannulation occurring after (median) 1 day (IQR:1-3 days). Compared to intra-operative application, post-operative ECMO showed more complications, cardiac reoperations (intra-operative:19.7%; post-operative: 24.8%, p=0.011), percutaneous coronary interventions (intra-operative:1.8%; post-operative: 3.6%, p=0.026), and had higher in-hospital mortality (intra-operative:57.5%; post-operative: 64.5%, p=0.002). Among hospital survivors, ECMO duration was shorter after intra-operative ECMO (median:104, IQR:67.8-164.2 hours) compared to post-operative ECMO (median:139.7, IQR:95.8-192 hours, p<0.001), while post-discharge long-term survival was similar between the two groups (p=0.86). Conclusions: Intra-operative and post-operative ECMO implantations are associated with different patients' characteristics and outcomes, with higher complications and in-hospital mortality after post-operative ECMO. Strategies to identify the optimal location and timing of post-cardiotomy ECMO in relation to specific patient's characteristics are warranted to optimize in-hospital outcomes.