Biomechanics and hemodynamics of stent-retrievers

Abstract

In 2015, multiple randomized clinical trials showed an unparalleled treatment benefit of stent-retriever thrombectomy as compared to standard medical therapy for the treatment of a large artery occlusion causing acute ischemic stroke. A short time later, the HERMES collaborators presented the patient-level pooled analysis of five randomized clinical trials, establishing class 1, level of evidence A for stent-retriever thrombectomy, in combination with intravenous thrombolysis when indicated to treat ischemic stroke. In the years following, evidence continues to mount for expanded use of this therapy for a broader category of patients. The enabling technology that changed the tide to support endovascular treatment of acute ischemic stroke is the stent-retriever. This review summarizes the history of intra-arterial treatment of stroke, introduces the biomechanics of embolus extraction with stent-retrievers, describes technical aspects of the intervention, provides a description of hemodynamic implications of stent-retriever embolectomy, and proposes future directions for a more comprehensive, multi-modal endovascular approach for the treatment of acute ischemic stroke.

The first virtual patient-specific thrombectomy procedure

“…In particular, the correct stent positioning appears to be an important procedural aspect to be taken into account. The complete stent expansion and clot compression in the second attempt, when compared to the first attempt, revealed the importance of the clot entrapment of the clot within the stent struts as a marker of potential success (Chueh et al, 2021;Kühn et al, 2020;Ospel et al, 2019;Tsumoto et al, 2017). Features like these can be clearly detected and foreseen by a computational simulation, which can help interventionists to optimize their treatment techniques, for example by modeling a different stent retriever.…”

“…Despite improvements since the first-generation thrombectomy devices, distal embolism due to clot fragmentation remains a significant challenge for MT procedures (Kühn et al, 2020). In general, all endovascular MT techniques and devices carry a significant risk of thrombus fragmentation and subsequent distal emboli with associated adverse clinical outcomes (Gralla et al, 2006;Kaesmacher et al, 2017;Po Sit, 2009).…”

“…Procedural success, defined as removal of the clot and revascularization of the brain, is dependent on the chance to remove the clot in toto with one or more passes. Many investigators have attempted to improve the interaction between thrombectomy devices and thrombus to increase successful revascularization rates (Chueh et al, 2021;Kühn et al, 2020;Ospel et al, 2019).…”

Applicability analysis to evaluate credibility of an in silico thrombectomy procedure

“…-The mechanical properties of the vascular tree and the blood flow conditions of the patient (e.g. pressures, flow rate) (Kühn et al, 2020).…”

Impact of the Internal Carotid Artery Morphology on in silico Stent-Retriever Thrombectomy Outcome

“…An AIS arises when a large vessel occlusion caused by a thromboembolus (clot) prevents blood supply to the brain tissues. Despite the promising and encouraging results, complications may occur, such as thrombus fragmentation, vascular damage, or microembolization ( 1 , 2 ).…”