Mechanical Thrombectomy for Acute Pulmonary Embolism

Official title

A Prospective, Multicenter, Randomized Controlled Trial of the Catheter-directed Mechanical Thrombectomy Compared to Standard Anticoagulation for Use in the Treatment of Acute Intermediate-risk Pulmonary Embolism.

Overview

Research Objective: To prospectively compare the efficacy and safety of a pre-collaboratively developed ultra-thin PTFE minimally invasive thrombectomy system versus standard pharmacological therapy in patients with acute pulmonary embolism (PE), both administered on top of standard care. Research Content: Patients meeting all the following criteria will be enrolled: Aged 18-75 years (male or female) Clinically diagnosed with acute PE Right ventricular/left ventricular diameter ratio (RV/LV) ≥0.9 on computed tomographic pulmonary angiography (CTPA) Provision of voluntary written informed consent. Study Design: After confirming eligibility, subjects will be randomized at a 1:1 ratio into two groups: Innovative Device Group: Minimally invasive thrombectomy Standard Pharmacological Therapy Group: Pharmacological thrombolysis + anticoagulation Study Endpoints: Primary Efficacy Endpoint: Reduction in RV/LV ratio (measured by CTPA) from baseline to 48 hours post-treatment. Primary Safety Endpoint: Incidence of Major Adverse Events (MAEs) from baseline to 48 hours post-treatment, defined as: Procedure-related death Major bleeding (per VARC-2 criteria: life-threatening, disabling, or major bleeding) Treatment-related clinical deterioration, including: Unplanned mechanical ventilation Arterial hypotension (systolic blood pressure \<90 mmHg for \>1 hour or requiring vasopressors) or shock Cardiopulmonary resuscitation Sustained deterioration in oxygenation Emergency surgical embolectomy. Key Terminology Notes: RV/LV: Right Ventricular/Left Ventricular diameter ratio (standard medical abbreviation retained). VARC-2: Valve Academic Research Consortium-2 (internationally recognized bleeding criteria). PTFE: Polytetrafluoroethylene (material name preserved). MAE: Major Adverse Events (acronym defined at first use). Clinical deterioration: Explicitly specified with objective clinical indicators. This translation maintains scientific precision while adhering to international clinical trial reporting standards (ICH-GCP). The structure aligns with typical English-language study protocols for clarity and reproducibility.

Detailed description

1. Research Objective To prospectively evaluate the comparative efficacy and safety of a novel ultra-thin polytetrafluoroethylene (PTFE) minimally invasive thrombectomy system versus guideline-directed pharmacological thrombolysis in patients with acute intermediate-high-risk pulmonary embolism (PE), both administered as adjuncts to standard anticoagulation therapy. 2. Study Population

Inclusion Criteria:

Adults aged 18-75 years (all genders)

Acute PE confirmed by computed tomographic pulmonary angiography (CTPA) within 14 days of symptom onset

Right ventricular dysfunction defined as RV/LV diameter ratio ≥0.9 on baseline CTPA

Provision of written informed consent

Exclusion Criteria:

Absolute contraindications to thrombolysis (e.g., active bleeding, recent intracranial hemorrhage, major surgery within 14 days)

Hemodynamic instability requiring immediate rescue therapy (systolic BP \<90 mmHg with end-organ hypoperfusion)

Severe renal impairment (eGFR \<30 mL/min/1.73m²) or hepatic failure (Child-Pugh Class C)

Life expectancy \<6 months due to non-PE comorbidities 3. Study Design Design: Prospective, multicenter, open-label, randomized controlled trial with blinded endpoint adjudication

Randomization: Eligible subjects stratified by PE severity (RV/LV: 0.9-1.0 vs. \>1.0) and thrombus burden (main/lobar vs. segmental PA involvement), then randomized 1:1 via centralized web-based system.

Intervention Groups:

Group A (Innovative Device):

Ultra-thin PTFE thrombectomy catheter deployed under fluoroscopic guidance via femoral access

Procedure completion within 90 minutes; mandatory peri-procedural unfractionated heparin (target ACT 250-300 s)

Post-procedure: Enoxaparin 1 mg/kg BID → transitioned to rivaroxaban 20 mg OD at 24 hours

Group B (Standard Therapy):

Alteplase infusion: 10 mg bolus + 90 mg over 2 hours (max 100 mg)

Concurrent heparin infusion (target aPTT 60-80 s) → switched to rivaroxaban 15 mg BID (Day 1-21) → 20 mg OD thereafter 4. Endpoint Definitions Primary Efficacy Endpoint Absolute reduction in RV/LV ratio from baseline to 48 hours post-intervention, measured by blinded core-lab CTPA analysis.

Primary Safety Endpoint

Composite Major Adverse Events (MAEs) within 48 hours, including:

Procedure-related mortality

Major bleeding per VARC-2 criteria:

Fatal bleeding

Intracranial hemorrhage

Bleeding causing ≥3 g/dL hemoglobin drop or transfusion of ≥2 units

Bleeding requiring surgical intervention

Treatment-related clinical deterioration:

Unplanned mechanical ventilation

Sustained hypotension (SBP \<90 mmHg for \>1 hour requiring vasopressors)

Cardiopulmonary resuscitation

New requirement for ECMO or emergency surgical embolectomy 5. Statistical Analysis Plan

Sample Size: 142 subjects/group (total N=284) providing 90% power (α=0.05) to detect:

Efficacy: Mean RV/LR reduction difference of 0.15 (SD=0.3)

Safety: 40% relative risk reduction in MAEs (Group A: 10% vs. Group B: 17%)

Analysis Sets:

Primary analysis: Modified intention-to-treat (mITT; all randomized receiving ≥1 treatment component)

Safety analysis: As-treated population

Methods:

Interventions

• Procedure Innovative Device Group
  Catheter-based thrombectomy is performed within 4 hours after baseline CTPA acquisition. Pre-procedural anticoagulation with either low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) is administered prior to thrombectomy. Post-procedural oral anticoagulation is transitioned to rivaroxaban 20 mg once daily (QD).
• Drug Standard Pharmacological Therapy Group
  Following thrombolytic agent administration, anticoagulation with rivaroxaban is initiated and maintained at 15 mg twice daily (BID) for the initial 3 weeks, then switched to 20 mg once daily (QD) thereafter.

Primary outcome measures

• Primary Efficacy Endpoint [Time frame: 48 hours post-treatment.]
• Primary Safety Endpoint: [Time frame: 48 hours post-treatment]

Eligibility criteria

Inclusion criteria

• Aged 18-75 years (male or female)
• Clinically diagnosed with acute PE
• Right ventricular/left ventricular diameter ratio (RV/LV) ≥0.9 on computed tomographic pulmonary angiography (CTPA)
• Provision of voluntary written informed consent.

Exclusion criteria

• Target vessel diameter <6 mm
• Calcification, plaque, or stenosis in target lesion
• Sustained systolic blood pressure <90 mmHg for >15 minutes or requiring vasopressors to maintain SBP ≥90 mmHg
• Peak pulmonary artery pressure >70 mmHg
• Hematocrit <28%
• History of chronic pulmonary hypertension
• Pre-existing left bundle branch block
• Chronic left heart failure with left ventricular ejection fraction (LVEF) ≤30%
• Renal dysfunction (serum creatinine >1.8 mg/dL or >159 μmol/L)
• Known coagulopathy or bleeding diathesis:

Platelet count <50×10⁹/L, or International Normalized Ratio (INR) >3

• Contraindications to antiplatelet/anticoagulant therapy
• Cardiothoracic or pulmonary surgery within 7 days prior
• Intracardiac thrombus
• Patients on extracorporeal membrane oxygenation (ECMO)
• Known hypersensitivity to iodinated contrast media
• Significant comorbidities complicating treatment/evaluation:

Active malignancy Acute infectious disease/sepsis Systemic conditions precluding procedure tolerance Life expectancy <1 year

• Pregnant or lactating women
• Concurrent participation in other drug/device trials
• Other investigator-determined unsuitability

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Treatment

Study locations

Center list to be confirmed — check the primary protocol.

Publications

• Wang C, Fang P, Zhou D, Xu B, Dai X, Zhang Z, Xie M, Duan Z, Zhang L, Li Y, Zhu Y, Jiang Y, Qie L, Shi H, Feng J, Zhang W, Jin X. Multi-center Randomized Controlled Trial of Catheter-Directed Mechanical Thrombectomy Versus Systemic Thrombolysis in Patients with Acute Intermediate-to-High-Risk Pulmonary Embolism: Study Protocol. Cardiovasc Intervent Radiol. 2026 Jun;49(6):1210-1218. doi: 10.1007/s0 PMID 42056311

Identifiers

NCT: NCT07032025 · EARLY-MYO-PE

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗