Effectiveness of pharmacological thrombolysis on clinical outcomes in high-risk pulmonary embolism patients with extracorporeal membrane oxygenation: a nationwide inpatient database study

Background Current guidelines recommend systemic thrombolysis as the first-line reperfusion treatment for patients with high-risk pulmonary embolism (PE) who present cardiogenic shock but do not require extracorporeal membrane oxygenation (ECMO). However, little is known about the optimal reperfusion treatment in high-risk PE patients requiring ECMO. We aimed to evaluate whether pharmacological thrombolysis improved high-risk PE patients’ outcomes who received ECMO. Methods This was a retrospective cohort study using the Japanese Diagnosis Procedure Combination inpatient database from April 2010 to March 2021. We identified patients who were diagnosed with PE and received ECMO on the day of admission. Patients who received pharmacological thrombolysis on the same day of ECMO initiation were defined as the thrombolysis group, and the remaining patients as the control group. The primary outcome was in-hospital mortality and secondary outcomes were favourable neurological outcomes, length of the hospital stay, length of the ECMO, total hospitalization cost, major bleeding, and blood transfusion volume. Propensity-score inverse probability of treatment weighting (IPTW) was performed to compare the outcomes between the groups. Results Of 1,248 eligible patients, 391 (31%) received pharmacological thrombolysis on the same day of ECMO initiation. Among the unweighted cohort, patients in the thrombolysis group were less likely to have poor consciousness at admission, out-of-hospital cardiac arrest, and left heart catheterization. After IPTW, the patient characteristics were well-balanced between the two groups The crude in-hospital mortality was 52% in the thrombolysis group and 59% in the control group. After IPTW, in-hospital mortality did not differ significantly between the two groups (risk difference: -2.1%, 95% confidence interval: -8.6–4.3%). There were also no significant differences in the secondary outcomes including the favourable neurological outcomes, length of hospital stay, length of ECMO, total hospitalization cost, major bleeding, and blood transfusion volume. Conclusions Pharmacological thrombolysis was not associated with a reduced in-hospital mortality or increased major bleeding in the high-risk PE patients receiving ECMO.