Background <p>Treatment of intermediate–high-risk pulmonary embolism is still debated. Interventional therapy is being increasingly widely applied in clinical practice. Numerous studies have confirmed that interventional therapy is effective. Both catheter-directed thrombolysis (CDT) and mechanical thrombectomy (MT) showed improvement in some efficacy outcomes compared with anticoagulation monotherapy. A recent study showed that MT has lower rates of clinical deterioration and/or bailout and postprocedural intensive care unit use compared with CDT, with no difference in mortality or bleeding, which makes the application of MT in clinical practice increasingly widespread. Recently, STORM-PE, the first randomized controlled trial to test the efficacy and evaluate the safety of MT combined with anticoagulation compared with anticoagulation monotherapy for the treatment of intermediate–high-risk pulmonary embolism, showed that treatment with MT combined with anticoagulation resulted in a significantly greater reduction in right ventricular/left ventricular (RV/LV) diameter ratio at 48&#xa0;h versus anticoagulation monotherapy, with comparably low rates of major adverse events in both treatment arms. However, whether MT combined with anticoagulation is more effective than anticoagulation monotherapy needs more evidence, especially in Asian populations.</p> Methods <p>The CAPE study is a currently enrolling national multicenter randomized controlled trial (RCT) comparing MT with MPA 8F guiding catheter [Cordis (Shanghai) Medical Device Co., Ltd] combined with anticoagulation vs anticoagulation monotherapy. A total of 156 patients with acute intermediate–high-risk pulmonary embolism stratified by the classification of the latest guideline of European Society of Cardiology (ESC) will be enrolled and randomized in a 1:1 ratio. The primary efficacy endpoint was reduction of RV/LV diameter ratio assessed by computed tomographic angiography (CTPA) at 48&#xa0;h. The secondary efficacy endpoint was the incidence of chronic thromboembolic pulmonary disease including chronic thromboembolic pulmonary hypertension. The primary safety endpoint was serious adverse events including major bleeding through 3&#xa0;months visit.</p> Discussion <p>CAPE is a RCT to compare the short and long efficacy of MT combined with anticoagulation and anticoagulation monotherapy for acute intermediate-high pulmonary embolism. The result will give more evidence for selection of different strategies for physicians.</p> Trial registration <p>CAPE study is registered in Chinese Clinical Trial Registry identifier (ChiCTR2500095253,&#xa0;<a href="https://www.medicalresearch.org.cn/clinicalResearch/researchInfo?id=c57630b7-51ec-4b24-83e1-85b9c0a835d6">https://www.medicalresearch.org.cn/clinicalResearch/researchInfo?id=c57630b7-51ec-4b24-83e1-85b9c0a835d6</a>). Registered on&#xa0;November 26 2024.</p>