Outcomes by cannulation methods for venovenous extracorporeal membrane oxygenation during COVID-19: A multicenter retrospective study

Purpose: To determine if a cannulation method for venovenous extracorporeal membrane oxygenation (V-V ECMO) is related to patient outcome. Methods: A retrospective, multicenter study of adult patients (>= 18 years old) placed on V-V ECMO for severe respiratory failure due to COVID-19 between March 1, 2020, to April 30, 2021. Patients were divided into the following three groups based on the initial cannulation method: (1) femoral vein-femoral vein or femoral vein-internal jugular vein (dual-site, C-DS), (2) single, dual-lumen cannula in internal jugular vein with tip positioned in the pulmonary artery (C-PA), and (3) single, dual-lumen cannula in internal jugular vein with tip positioned in the inferior vena cava (C-IVC). The primary outcome was in-hospital mortality assessed by a time-to-event analysis. Results: Overall, 435 patients from 17 centers comprised the study cohort. C-DS was performed in 247 (57%, age: 49, IQR:39-57 years; 30% female) cases, 99 (23%, age: 53, IQR: 42-59 years; 26% female) received C-PA, and 89 (20%) patients got C-IVC (age: 46, IQR 35-54; 33% female). At 90-days, in-hospital mortality was 60% (C-DS), 41% (C-PA), and 61% (C-IVC), p = 0.06. After adjustment for clinical characteristics, the likelihood of in-hospital mortality in comparison to C-DS, was lower with C-PA (aHR: 0.52, 95%CI 0.32-0.85, p = 0.009) and similar with C-IVC (aHR: 0.96, 95%CI 0.63-1.47, p = 0.86). Conclusion: Catheter-directed flow into the PA bypassing the right ventricle with a single dual-lumen cannula is associated with reduced mortality during V-V ECMO for COVID-19. These findings are limited by residual confounding and site-clustering. Further investigation is urgently warranted with randomized studies.