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Rationale and design of the DEFIANCE study: A randomized controlled trial of mechanical thrombectomy versus
Steven D Abramowitz1, Xhorlina Marko2, Donna D'Souza3
1MedStar Health, Washington, DC.
Insights
The DEFIANCE study is the first randomized controlled trial comparing mechanical thrombectomy to anticoagulation for deep vein thrombosis (DVT). Results will guide iliofemoral DVT treatment and post-thrombotic syndrome prevention.
Area of Science:
- Vascular Medicine
- Interventional Cardiology
- Clinical Trials
Background:
- Deep vein thrombosis (DVT) is a prevalent condition with significant long-term complications like post-thrombotic syndrome (PTS).
- Standard treatment for iliofemoral DVT involves anticoagulation alone.
- Mechanical thrombectomy is increasingly used for DVT, but lacks comparative data from randomized studies.
Purpose of the Study:
- To compare mechanical thrombectomy with anticoagulation alone for treating lower extremity DVT.
- To evaluate the efficacy and safety of an interventional strategy involving the ClotTriever System versus standard anticoagulation.
- To assess the impact on post-thrombotic syndrome (PTS) severity and other clinical outcomes.
Main Methods:
- The DEFIANCE study is an international randomized controlled trial (RCT) enrolling approximately 300 patients with unilateral iliofemoral DVT.
- Participants are randomized 1:1 to receive either mechanical thrombectomy with the ClotTriever System or anticoagulation alone.
- The primary endpoint is a composite win ratio assessing treatment failure (amputation, gangrene, mortality) and PTS severity at 6 months.
Main Results:
- This section is not applicable as the study is actively enrolling and results are not yet available.
Conclusions:
- The DEFIANCE trial is the first RCT to directly compare mechanical thrombectomy-based interventions with anticoagulation for DVT.
- Study findings are anticipated to inform clinical practice for managing iliofemoral DVT and preventing PTS-related morbidity.
Background:
Deep vein thrombosis (DVT) is a common medical condition that is associated with clinically significant sequelae, including postthrombotic syndrome (PTS). Anticoagulation alone remains the guideline-recommended treatment for many patients with iliofemoral DVT. Recent technological advances have led to an increase in the use of mechanical thrombectomy for DVT, but mechanical thrombectomy-based procedures have not yet been compared with standard-of-care anticoagulation therapy in randomized studies.
Methods:
The DEFIANCE study (ClinicalTrials.gov: NCT05701917) is an international and actively enrolling randomized controlled trial (RCT) in lower extremity DVT assessing an interventional strategy that includes mechanical thrombectomy with the ClotTriever System (Inari Medical, Irvine, CA) versus anticoagulation alone. Approximately 300 patients with unilateral iliofemoral DVT and symptom duration ≤ 12 weeks will be randomized 1:1. Study conduct includes an independent core laboratory for duplex ultrasound assessment, an independent medical monitor for safety adjudication, and evaluation of PTS severity on the Villalta scale using best clinical practices. The primary endpoint is a composite outcome structured as a hierarchal win ratio of 1) the occurrence of treatment failure or therapy escalation as adjudicated by the medical monitor, with failure defined as amputation or gangrene of the target leg or venous thromboembolism-related mortality, and 2) the assessment of PTS severity at the 6-month follow-up visit. In addition to being a component of the primary endpoint, the severity of PTS at 6 months is also evaluated as a stand-alone secondary endpoint. An additional secondary endpoint is a composite of outcomes at the 10-day visit and is structured as a hierarchal win ratio of 1) vessel compressibility on duplex ultrasound, 2) patient-reported pain, and 3) improvement of edema. The safety endpoints are access site complications requiring endovascular or surgical repair and the occurrence through the 30-day visit of mortality, major bleeding, or new symptomatic pulmonary embolism.
Conclusions:
DEFIANCE will be the first RCT to evaluate a mechanical thrombectomy-based interventional approach versus anticoagulation therapy alone for DVT. The results will inform the treatment of patients with iliofemoral DVT and the prevention of PTS-associated morbidity.
Trial Registration:
DEFIANCE: RCT of ClotTriever System Versus Anticoagulation In Deep Vein Thrombosis (DEFIANCE), ClinicalTrials.gov: NCT05701917, URL: https://clinicaltrials.gov/study/NCT05701917?cond=Deep%20Vein%20Thrombosis&term=defiance&rank=1.
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