Referral and outcomes of mechanical thrombectomy for pulmonary embolism - a single-centre experience

Abstract Funding Acknowledgements None. Introduction Acute pulmonary embolism (PE) is a significant cause of morbidity and mortality, and percutaneous catheter-based treatments have emerged as an effective treatment option alongside thrombolysis. However, data concerning long-term outcomes are scarce. Methods All patients referred to a tertiary centre for pulmonary angiography with the intent to perform mechanical thrombectomy in the context of acute PE between January 2016 and August 2023 were retrospectively included and clinical data and outcomes were collected. Results Fifty-two patients (58% female; mean age 66±18 years) were referred to pulmonary angiography in the setting of acute PE, of whom 40 patients (77%) underwent continuous aspiration mechanical thrombectomy with an overall success rate of 70%. Twenty-eight percent of patients had bilateral thrombus. Thirty-two patients had intermediate-high risk or high-risk PE, and the mean Pulmonary Embolism Severity Index (PESI) was 146 points. Thirteen patients (25%) underwent thrombolysis prior to angiography, while 15 patients (28%) had an absolute or relative contraindication for thrombolysis. Ventilation/perfusion scans were performed in ten patients (19%) during the follow-up period, of whom five patients (10%) had evidence of residual illness, with no significant differences between the thrombectomy and non-thrombectomy groups (p=0.8). The overall mortality rate over the complete follow-up period was 39%, while 25% of patients died within 48 hours of the procedure. Predictors of mortality on univariate analysis included older age (HR 1.06 95% CI 1.00-1.11, p = 0.03), history of chronic obstructive pulmonary disease (HR 3.88 95% CI 1.41-10.69, p = 0.01), history of previous deep vein thrombosis or PE (HR 3.40 95% CI 1.34-8.63, p = 0.01), thrombolysis prior to referral for mechanical thrombectomy (HR 5.94 95% CI 1.93-18.26, p 0.01), shock or haemodynamic instability (HR 8.50 [95% CI 2.44-29,52, p 0.01) and resuscitated cardiac arrest (HR 5.98 95% CI 2.34-15.30, p 0.01). On Cox multivariate analysis, the presence of shock or haemodynamic instability was a predictor of increased mortality (HR 5.23 95% CI 1.12-24.3, p = 0.04). Conclusions Intermediate and high risk acute PE is a clinical entity with a high morbidity and mortality rate regardless of treatment strategy, particularly during the index hospitalization and in patients with shock or haemodynamic instability.