Background:
The optimal reperfusion strategy for acute intermediate-high-risk pulmonary embolism remains uncertain. These patients present with right ventricular dysfunction and myocardial injury but are haemodynamically stable. Systemic thrombolysis may improve pulmonary haemodynamics, but bleeding risk limits its use. Large-bore mechanical thrombectomy with FlowTriever enables immediate thrombus removal without routine thrombolytics and may facilitate early right ventricular unloading.
Objective:
To assess early haemodynamic, respiratory and clinical outcomes after FlowTriever thrombectomy in patients with acute intermediate-high-risk pulmonary embolism.
Methods:
Retrospective single-center analysis of consecutive patients with acute pulmonary embolism treated with FlowTriever thrombectomy. The primary cohort included patients with intermediate-high-risk pulmonary embolism, defined by right ventricular dysfunction on CT or echocardiography plus elevated cardiac biomarkers. Intermediate-low-risk patients were excluded from primary analysis.
The primary endpoint was early right ventricular unloading, assessed by change in RV/LV ratio and echocardiographic parameters. Secondary endpoints included changes in heart rate, oxygenation, systolic and invasive mean pulmonary artery pressure. Safety outcomes included procedural success, major bleeding, access-site complications, bailout thrombolysis, ICU and hospital length of stay, recurrent pulmonary embolism and 30-day mortality. Paired comparisons were performed using the Wilcoxon signed-rank test.
Results:
A total of 22 patients were included. 18 fulfilled criteria for intermediate-high-risk pulmonary embolism. Median age was 68.0 years (IQR 64.0–77.0), and 11 patients were female (61.1%). Active cancer was present in 4 patients (22.2%). All had right ventricular dilatation at baseline, 17 patients (94.4%) had elevated troponin and 16 patients (88.9%) had elevated NT-proBNP. Bilateral pulmonary embolism was present in 17 patients (94.4%), central thrombus burden in 16 patients (88.9%).
RV/LV ratio decreased from 1.2 (IQR 1.1–1.3) to 0.9 (IQR 0.8–1.0; n=17; p<0.001). Mean pulmonary artery pressure decreased from 28.0 mmHg (IQR 24.5–34.0) to 22.0 mmHg (IQR 16.0–28.5; n=17; p<0.001). TAPSE increased from 17.5 mm (IQR 16.0–19.0) to 21.0 mm (IQR 19.0–22.0; p<0.001), systolic pulmonary artery pressure decreased from 45.0 mmHg (IQR 34.5–57.5) to 25.0 mmHg (IQR 22.0–28.0; n=17; p<0.001). Heart rate decreased from 102.5 bpm (IQR 91.0–111.0) to 85.5 bpm (IQR 76.0–96.0; p=0.020), and oxygen saturation improved from 89.0% (IQR 88.0–94.0) to 97.0% (IQR 93.0–99.0; p<0.001).
Procedural success was achieved in all patients. No major bleeding, access-site complications, bailout thrombolysis, adjunctive local lysis or ECMO occurred. Median ICU length of stay was 2.0 days (IQR 2.0–2.0), median hospital length of stay was 5.0 days (IQR 3.0–6.0). No 30-day mortality or recurrent pulmonary embolism was observed.
Conclusion:
FlowTriever thrombectomy was feasible and associated with early right ventricular unloading, improved pulmonary haemodynamics and rapid clinical stabilization in intermediate-high-risk pulmonary embolism. Avoiding thrombolytics was accompanied by low bleeding and vascular complication rates. These findings support further evaluation of large-bore mechanical thrombectomy in carefully selected patients.
