Effectiveness and major bleeding complications with venoarterial extracorporeal membrane oxygenation in category E pulmonary thromboembolism: a multicentre retrospective study

Background Evidence supporting venoarterial extracorporeal membrane oxygenation (VA-ECMO) in Category E pulmonary thromboembolism (PTE) under the 2026 American Heart Association/American College of Cardiology guideline remains limited. We evaluated associations with 30-day mortality and in-hospital major bleeding.Methods This multicentre retrospective cohort included consecutive patients with Category E PTE admitted to four tertiary centres in Southwest China from January 2019 to August 2025. Primary outcomes were 30-day all-cause mortality and in-hospital major bleeding. Mortality was evaluated using Kaplan-Meier analysis and Cox regression. Major bleeding was analysed using Fine-Gray regression with death before bleeding as a competing event.Results Among 95 patients, 39 received VA-ECMO and 56 did not. 30-day mortality was 43.6% and 62.5%, respectively. VA-ECMO was associated with lower mortality in the multivariable model (adjusted HR 0.44, 95% CI 0.22 to 0.88). Major bleeding occurred in 35.9% of VA-ECMO recipients and 16.1% of patients without VA-ECMO (unadjusted subdistribution HR (sHR) 2.50, 95% CI 1.11 to 5.64; p=0.027). The adjusted association was not statistically significant (sHR 1.18, 95% CI 0.44 to 3.12; p=0.743).Conclusions In patients with Category E PTE, VA-ECMO was associated with lower 30-day mortality after adjustment for baseline differences. Although in-hospital major bleeding was more frequent among VA-ECMO recipients in unadjusted analyses, this association was not statistically significant after multivariable adjustment. Cardiac arrest and baseline creatinine and fibrinogen levels were independently associated with major bleeding.