Acute ischemic stroke (AIS) is a leading cause of mortality and long-term disability worldwide. It occurs when a blood clot forms in a vessel supplying the brain, leading to a reduction in blood flow and oxygen supply to brain tissue. Large vessel occlusion (LVO) is a severe form of AIS that requires prompt intervention to prevent irreversible brain damage. Mechanical thrombectomy (MT)by stent retrievers has emerged as a game-changer in the management of LVO in recent years, and it offers hope to patients who would otherwise have limited treatment options.
MT involves the use of mechanical devices to physically remove the clot responsible for the LVO. Stent retrievers are the most commonly used mechanical thrombectomy devices and are designed to capture and retrieve the clot with a stent-like structure that is deployed across the occlusion. The retrieval of the clot restores blood flow quickly, minimizing brain damage and improving the patient's chances of recovery.
The effectiveness of MT by stent retrievals has been demonstrated in several clinical trials and observational studies. The landmark randomized controlled trials (RCTs) - the MR CLEAN, ESCAPE, SWIFT PRIME, and EXTEND IA - showed significant clinical benefits of MT in patients with AIS due to LVO, including a higher rate of functional independence at 90 days, reduced mortality, and improved quality of life. The results were so convincing that some trials were stopped prematurely to offer MT to all patients who met the inclusion criteria.
The technology used in MT by stent retriever thrombectomy devices has since rapidly evolved, with newer devices offering more advanced features such as the ability to reposition the clot before retrieval and reduce the number of passes required to achieve complete revascularization. The use of imaging techniques such as CT angiography and perfusion imaging to select eligible patients for MT has also improved the accuracy of patient selection and the outcomes of the procedure.
Mechanical thrombectomy by stent retriever device has become a standard of care for patients with AIS due to LVO, and is now recommended as first-line therapy by international guidelines, including the American Heart Association/American Stroke Association and the European Stroke Organisation guidelines. MT has also been shown to be cost-effective, with a favorable cost per quality-adjusted life year compared to standard care or intravenous tissue plasminogen activator (IV tPA) alone.
However, mechanical thrombectomy is not without risks, and its success highly depends on the patient's comorbidities, time to treatment, and expertise of the treating team. The procedure can lead to complications such as vessel perforation, dissection, or embolization, although these occur in less than 5% of cases. Moreover, some patients may not be suitable for MT due to contraindications such as the presence of a large infarct core or the absence of significant clinical deficits.
In summary, mechanical thrombectomy by stent retrievers is a safe and effective treatment for patients with AIS due to LVO, and it offers potentially life-saving benefits to patients who would otherwise have limited treatment options. MT has revolutionized the management of AIS, and it has set a new standard of care in stroke treatment. Further developments in technology and patient selection criteria are expected to further improve the outcomes of MT and increase its accessibility to more patients in need of this life-saving intervention.