Outcomes with venoarterial vs venovenous extracorporeal membrane oxygenation as a bridge to lung transplantation in interstitial lung disease

Background The evidence on outcomes associated with cannulation type-venoarterial (VA) versus venovenous (VV) of extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation (LTx) in patients with interstitial lung disease (ILD) is limited. Methods Using the United Network for Organ Sharing (UNOS) Standard Transplant Analysis and Research (STAR) registry, a retrospective cohort study was conducted on ILD patients bridged with ECMO for LTx. Outcomes by cannulation type (VV vs VA) were analyzed. 1:1 propensity matching between VV and VA ECMO patients was performed to reduce selection bias. Results The cohort included 1551 patients, with 1236 (79.7%) on VV ECMO and 315 (20.3%) on VA ECMO. Patients bridged with VA ECMO experienced a higher rates of delisting from the waitlist due to death or deterioration in both the overall (41% vs 27%, p<0.001) and matched (41% vs 30%, p=0.003) cohorts. Bridging with VA ECMO when compared to VV ECMO was associated with a higher 1-year post-transplant mortality in the overall (33% vs 24%, p<0.001), but not meeting statistical significance in the matched cohort (33% vs 24%, p=.059). In the multivariate Cox-proportional hazard regression analysis, the adjusted Hazard Ratio (aHR) for 1-year post-transplant mortality with VA ECMO compared to VV ECMO was 1.01 (95% Confidence Interval, CI 0.65 – 1.60, p>0.9) in the overall and 1.24 (95% CI 0.78 – 1.97, p=0.4) in the matched cohort. The subgroup analysis was significant for a higher mortality with VA- compared to VV ECMO in the setting of COVID-19 associated pulmonary fibrosis (aHR 7.12, 95% CI 1.9 – 26.6, p=0.003). Conclusion VV ECMO was associated with a more successful bridge to LTx than VA ECMO. Adjusted post-transplant outcomes were comparable between ILD patients bridged with VA and VV ECMO. Given the lack of granularity of the clinical data in the UNOS STAR database, prospective studies are needed to further investigate the outcome differences in ILD patients bridged with VA versus VV ECMO.