First Belgian experience with large-bore mechanical thrombectomy in acute pulmonary embolism using the FlowTriever® system: a bi-centre retrospective analysis.

BACKGROUND: Pulmonary embolism (PE) is a major cause of cardiovascular morbidity and mortality. Large-bore mechanical thrombectomy (LBMT) is an emerging treatment for high-risk and intermediate-high-risk PE, particularly in patients with contraindications to thrombolysis. We evaluated the safety, efficacy, and clinical outcomes of LBMT using the FlowTriever® system in a bi-centre cohort. METHODS: We retrospectively analysed patients treated with FlowTriever® for acute PE between February 2022 and November 2024 at two high-volume Belgian centres. Clinical, hemodynamic, and procedural data were collected. Primary endpoints were reduction in mean pulmonary artery pressure (mPAP), major procedural complications, and 30-day mortality. Secondary endpoints included technical success and length of ICU and hospital stay. RESULTS: Sixty patients (mean age 61.9 ± 13.9 years; 51.7% male) underwent LBMT; 81.7% had intermediate-high-risk and 13.3% high-risk PE. Technical success was achieved in 96.7% of cases. Mean mPAP decreased by 27% (p < 0.0001). Major complications occurred in 5%, including two pulmonary artery perforations in acute-on-chronic PE and one intraoperative cardiac arrest. No major bleeding events were observed. Thirty-day mortality was 5%, and survival to discharge was 93.3%. Median ICU and hospital stays were 3 [2-6] and 7 [5-12] days. Elevated lactate was significantly associated with adverse outcomes (p = 0.009). CONCLUSION: LBMT with FlowTriever® achieved rapid hemodynamic improvement and high technical success in selected patients. Careful selection and operator experience are essential. Prospective comparative studies are needed to clarify long-term benefit and optimise treatment strategies.