Rationale and design of a randomized controlled pilot trial to assess stent retriever thrombectomy for thrombus burden reduction in patients with acute myocardial infarction: The RETRIEVE-AMI study.

BACKGROUND: ST-elevation myocardial infarction (STEMI) is typically caused by thrombotic occlusion of a coronary artery with subsequent hypoperfusion and myocardial necrosis. In approximately half of patients with STEMI, despite successful restoration of epicardial coronary patency, downstream myocardium perfusion remains impeded. Coronary microvascular injury is one of the key mechanisms behind suboptimal myocardial perfusion and it is primarily, yet not exclusively, related to distal embolization of atherothrombotic material following recanalization of the culprit artery. Routine manual thrombus-aspiration has failed to show clinical efficacy in this scenario. This could be related with limitations in technology adopted as well as patients' selection. To this end, we set out to explore the efficacy and safety of stent retriever-assisted thrombectomy based on clot-removal device routinely used in stroke intervention.

STUDY DESIGN AND OBJECTIVES: The stent RETRIEVEr thrombectomy for thrombus burden reduction in patients with Acute Myocardial Infarction (RETRIEVE-AMI) study has been designed to establish whether stent retriever-based thrombectomy is safe and more efficacious in thrombus modification than the current standard of care: manual thrombus aspiration or stenting. The RETRIEVE-AMI trial will enrol 81 participants admitted for primary PCI for inferior STEMI. Participants will be 1:1:1 randomised to receive either standalone PCI, thrombus aspiration and PCI, or retriever-based thrombectomy and PCI. Change in thrombus burden will be assessed via optical coherence tomography imaging. A telephone follow-up at 6 months will be arranged.

CONCLUSIONS: It is anticipated by the investigators that stent retriever thrombectomy will more effectively reduce the thrombotic burden compared to current standard of care whilst being clinically safe.