RETRIEVE-AMI Study

Study Overview
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Brief Summary
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Heart attacks are caused by the sudden formation of a clot inside a diseased coronary artery which reduces blood flow beyond the blockage site. During conventional treatment of the blockage with what is known as a stent; a stainless steel tub that keeps the artery open, the clot that has formed is disrupted and is pushed further down leading to damage in smaller blood vessels supplying the heart muscle. This additional damage can lead to long-term heart muscle damage influencing recovery and wellbeing. The original concept that was tested to prevent this 'clot shower' was that of a suction device to withdraw the clot before stenting. However, this approach has not translated to patient benefit. Amongst the reasons put forward for the inefficacy of the suction device was that it does not remove the entire clot as it does not interact with it. A new device that physically interacts with the clot and traps it before pulling it out - the stent retriever - is now routinely used in stroke therapy to remove clots in the arteries supplying the brain. This device has been successfully used as a last resort to remove clots in a small number of heart attacks. The investigators hypothesize that stent retriever therapy will be more effective in clot removal than the current standard of care; suction or stenting. To study this, the investigators propose the RETRIEVE-AMI randomised controlled trial.

Official Title
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Stent Retriever Thrombectomy for Thrombus Burden Reduction in Patients With Acute Myocardial Infarction - RETRIEVE-AMI Study

Conditions
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Myocardial Infarction, Thrombus, Coronary Artery Disease

Intervention / Treatment
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* Device: Retriever Thrombectomy
* Procedure: Percutaneous Coronary Intervention
* Procedure: Thrombus Aspiration


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Primary PCI patient with ST elevation myocardial infarction (STEMI) TIMI 0 flow at presentation Angiographic thrombus score ≥ 4 Vessel diameter at site of occlusion ≥ 3.0 mm (measured by quantitative coronary angiography) Exclusion Criteria: Female participant who is pregnant or lactating Participant with known hypersensitivity to nickel-titanium Unconscious at presentation Late presenter (pain to wire time > 6 h) Class Killip III/IV and/or profound bradycardia (Heart rate < 40 bpm) Known history of kidney failure Ostial occlusion Highly tortuous vessel Highly calcified vessel Suspected (angiographically) spontaneous coronary artery dissection Stent thrombosis Previous stent implanted proximal to the occlusion site Previous coronary artery bypass graft surgery (CABG) Previous STEMI/Transient Ischemic Attack/Stroke Known anaemia (Hemoglobin <9)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The study will consist of 3 arms. Eligible participants will be 1:1:1 randomised to receive either standalone percutaneous coronary intervention (PCI) (Arm 1), thrombus aspiration + PCI (Arm 2) or retriever thrombectomy + PCI (Arm 3).
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standalone Percutaneous Coronary Intervention<br>Participants will have standard of care treatment. They will undergo PCI with devices and techniques driven by clinical decision making at the patient level and institutional level, and carried out in accordance with the Oxford University Hospitals NHS Foundation Trust department guidelines. | Procedure: Percutaneous Coronary Intervention<br>* Standard of care<br>|
| Active Comparator: Percutaneous Coronary Intervention and Thrombus Aspiration<br>Participants will have standard of care treatment with manual thrombectomy catheter and PCI. They will undergo PCI with devices and techniques driven by clinical decision making at the patient level and institutional level, and carried out in accordance with the Oxford University Hospitals NHS Foundation Trust department guidelines. | Procedure: Percutaneous Coronary Intervention<br>* Standard of care<br>Procedure: Thrombus Aspiration<br>* Standard of care treatment with manual thrombectomy catheter<br>* Other names: Aspiration-assisted thrombectomy;|
| Experimental: Percutaneous Coronary Intervention and Retriever Thrombectomy<br>Participants randomised to the stent-retriever thrombectomy arm of the RETRIEVE AMI trial will undergo stent-retriever thrombectomy with the SolitaireTM X Revascularisation Device. | Device: Retriever Thrombectomy<br>* The SolitaireTM X revascularisation device is a self-expanding stent designed for dynamic clot integration with radiopaque markers that enhance visualisation of the optimal working length. After a thrombotic occlusion has been identified and crossed with a guidewire, the stent-retriever thrombectomy proceeds. A microcatheter (e.g., PhenomTM, MarksmanTM) is advanced over the guidewire and once it has traversed the thrombotic occlusion, the SolitaireTM X device is advanced through the microcatheter until the usable length of the stent extends past each side of the thrombus in the vessel. As the microcatheter is retracted to the proximal radiopaque marker of the stent, the stent self-expands and entangles the thrombus. The microcatheter and SolitaireTM X Revascularisation Device are withdrawn as a unit into the guide catheter under continuous aspiration. PCI then proceeds driven by clinical decision making and department guidelines.<br>* Other names: Stent Retriever;Procedure: Percutaneous Coronary Intervention<br>* Standard of care<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thrombus volume (mm3) | Assessed with Optical Coherence Tomography [OCT] | Pre-stent implantation during PCI | 
| Device-related target vessel complications | Assessed with angiography and/or OCT | Pre-stent implantation during PCI | 
| Device deficiency | Assessed with angiography and/or OCT | Pre-stent implantation during PCI | 
| Major adverse cardiac and cerebrovascular events (MACCE) |  | Up to 30 days after PCI | 
| MACCE |  | At 6 months after PCI | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thrombus area (mm2) | Assessed with OCT | Pre-stent implantation during PCI | 
| Flow area (mm2) | Assessed with OCT | Pre-stent implantation during PCI | 
| Thromboatheroma area (mm2) | Assessed with OCT | Post-stent implantation during PCI | 
| Flow area (mm2) | Assessed with OCT | Post-stent implantation during PCI | 
| Stent expansion & apposition | Assessed with OCT | Post-stent implantation during PCI | 
| Thrombolysis in Myocardial Infarction (TIMI) flow | Assessed with angiography | Post-stent implantation during PCI | 
| Myocardial Blush Grade | Assessed with angiography | Post-stent implantation during PCI | 
| Angiography derived coronary physiology indices | Assessed with angiography | Post-stent implantation during PCI | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Myocardial Infarction, Percutaneous coronary intervention, Stent Retriever, Thrombus Aspiration