A randomized pilot trial for combined catheter-interventional treatment of intermediate high-risk pulmonary embolism

Background: Catheter-interventional treatments are increasingly used in patients with pulmonary embolism, and single-arm cohorts and retrospective data suggest beneficial effects. Available data describes effects for either catheter-based thrombectomy or local fibrinolysis, but there is almost no data regarding a combination of both approaches.

We aimed to assess safety and efficacy of a catheter-based thrombectomy in combination with local fibrinolytic treatment in comparison with conventional treatment in a single-center pilot study.

Methods: Patients with acute intermediate-high risk pulmonary embolism were randomized to a combined catheter-interventional treatment (CIT, thrombectomy with subsequent local fibrinolysis) plus conventional treatment or conventional treatment alone (CON) in a 2:1 ratio. The two co-primary outcome measures were a) change in right-ventricular/left-ventricular(RV/LV)-ratio and b) change in a clinical efficacy score (ratio of systolic blood pressure over heart rate and respiratory rate, with lower values indicating higher PE severity) 24h after randomization.

Results: Twenty patients were enrolled into this study, 13 in the CIT group and 7 in the CON group. Baseline blood pressure and clinical efficacy score were lower in the CIT group. Other clinical baseline characteristics were balanced between the groups. 24h after randomization, RV/LV-ratio was decreased in the CIT group but not in the CON group (-0.4±0.2 vs. 0.0±0.2, p<0.001 for between group comparison). Clinical efficacy score increased by 1.5±1.3% in the CIT group and decreased by -1.0±1.1% in the CON group (p<0.001). One patient in the CIT group died from recurrent pulmonary embolism 3 days after intervention. No bleeding events or other safety-relevant events were observed in any of the patients.

Conclusion: In this pilot study, CIT was found to be safe and clinically superior over conventional treatment in patients with acute pulmonary embolism. These results warrant confirmation in larger scaled studies in the future.