Impact of thrombus modification with stent retriever thrombectomy compared to manual thrombus aspiration and stenting alone on intracoronary thrombus burden and coronary flow in st segment elevation myocardial infarction

Thesis

ST-segment elevation myocardial infarction (STEMI) is typically caused by thrombotic coronary occlusion, resulting in myocardial hypoperfusion and necrosis. Despite re-opening the occluded artery with percutaneous coronary intervention (PCI), downstream myocardial perfusion often remains impeded, in part, due to embolization of thrombotic material. This results in prognostically relevant myocardial injury, particularly in STEMI with a large thrombus burden (LTB).

Manual aspiration (MA), when used, is the prevailing technique for removing coronary thrombus prior to stenting. However, routine MA use has failed to demonstrate reductions in major adverse cardiovascular events in STEMI, perhaps due to limitations of this thrombus aspiration technology and/or a lack of patient selection in trials. Stent-retriever thrombectomy (SRT) (using a “stent-retriever” device to extract thrombus), is a highly effective treatment for ischemic stroke. This thesis is the first to evaluate its efficacy and safety for extracting coronary thrombi in STEMI.

STEMI patients with LTB were prospectively randomized 1:1:1 to either PCI alone, MAassisted PCI or SRT-assisted PCI. Key outcome measures were: 1) change in coronary thrombus volume/burden pre- to post-thrombus modification; 2) microcirculatory resistance; 3) safety and 4) surrogates of myocardial perfusion and infarct size.

Both MA and SRT significantly reduced coronary thrombus volume and improved clinical surrogates compared to stenting alone. Coronary thrombus volume reduction increased proportionally with increasing baseline thrombus volume for both techniques. Notably, angiographic thrombus score was shown to be an unreliable indicator of true coronary thrombus burden, verified by intracoronary ocular coherence tomography (OCT). This thesis demonstrates the safety and feasibility of SRT in STEMI and underscores the potential value of thrombus modification in selected STEMI patients with a true LTB, especially when thrombus burden is accurately assessed using OCT.

Authors: Walsh, JL

• DOI: 10.5287/ora-avdoavm8r
• Type of award: D.M
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: ST-segment elevation myocardial infarction; microvascular obstruction; thrombectomy; stent-retreiver; STEMI
• Subjects: Cardiology