Catheter-Based Therapies for Intermediate-High Risk Pulmonary Embolism: A Protocol for a Systematic Review With Bayesian Pairwise and Network Meta-Analyses

Background: Intermediate-high risk pulmonary embolism (PE) represents a clinically challenging subgroup of acute PE, characterized by right ventricular dysfunction and increased risk of hemodynamic deterioration despite treatment with anticoagulation therapy. Although systemic thrombolysis may provide more rapid reperfusion, its use is limited by an increased risk of major bleeding. Catheter-based treatment strategies have emerged as potential alternatives, but their comparative efficacy and safety remain uncertain. Objective: To assess the benefits and harms of catheter-based treatment strategies compared with contemporary control regimens, including standard anticoagulation with or without systemic thrombolysis, in patients with intermediate-high risk PE. Methods: This protocol outlines a systematic review with Bayesian pairwise meta-analysis and network meta-analysis of randomized clinical trials evaluating catheter-based therapies for hospitalized patients with intermediate-high risk PE. Eligible interventions include catheter-directed thrombolysis, ultrasound-assisted thrombolysis, and catheter-based embolectomy. Comparators may include standard anticoagulation alone or in combination with systemic thrombolysis or other active control regimens reflecting standard of care. Searches will be conducted in relevant databases, supplemented by trial registries. Two reviewers will independently screen studies, extract data, and assess risk of bias using the Cochrane Risk of Bias 2 tool. Bayesian pairwise meta-analyses and network meta-analysis will be performed using weakly informative priors to synthesize direct and indirect evidence across interventions. Results will be reported as posterior effect estimates with 95% credible intervals. The primary outcome will be all-cause mortality. Secondary and exploratory outcomes include major bleeding as defined according to the criteria of the International Society on Thrombosis and Haemostasis within 7 days, hospital length of stay, and change in RV/LV ratio within 48 h. GRADE assessments will be performed where applicable. Discussion: This review will synthesize direct and indirect randomized evidence on catheter-based treatment strategies for intermediate-high risk PE. The findings may help clarify the role of these interventions in contemporary management, inform future guideline recommendations, and identify persistent evidence gaps requiring further large-scale randomized trials.