Endovascular therapy (EVT) has revolutionized the treatment of acute ischemic stroke. In the past few years, endovascular treatment indications have expanded to include patients being treated in the extended window, with large ischemic core infarction, basilar artery occlusion (BAO) thrombectomy, as demonstrated by several randomized clinical trials. Intravenous thrombolysis (IVT) bridging to mechanical thrombectomy has also been studied via several randomized clinical trials, with the overall results indicating that IVT should not be skipped in patients who are candidates for both IVT and EVT. Simplification of neuroimaging protocols in the extended window to permit non-contrast CT, CTA collaterals have also expanded access to mechanical thrombectomy, particularly in regions across the world where access to advanced imaging may not be available. Ongoing study of areas to develop include rescue stenting in patients with failed thrombectomy, medium vessel occlusion thrombectomy, and carotid tandem occlusions. In this narrative review, we summarize recent trials and key data in the treatment of patients with large ischemic core infarct, simplification of neuroimaging protocols for the treatment of patients presenting in the late window, bridging thrombolysis, and BAO EVT evidence. We also summarize areas of ongoing study including medium and distal vessel occlusion.
The minimal requirements for imaging studies prior to endovascular treatment (EVT) of acute ischemic stroke are those that can provide the information necessary to determine the indication for treatment (treatment triage) and procedural strategies without being time-consuming. An important notion is to determine whether the patient can benefit from EVT. We should recognize that the perfect diagnostic imaging technique does not yet exist, and each has advantages and disadvantages. Generally, stroke imaging protocols to triage for EVT include the following three options: 1) non-contrast CT and CTA, 2) CT perfusion and CTA, and 3) MRI and MRA. It is not known if perfusion imaging or MRI is mandatory for patients with stroke presenting within 6 hours of onset, although non-contrast CT alone has less power to obtain the necessary information. Dual-energy CT can distinguish between post-EVT hemorrhage and contrast agent leakage immediately after EVT.
This extensive review explores the intricacies of the three principal mechanical thrombectomy techniques: the stent retriever technique, contact aspiration technique, and a combined approach, and their application in managing acute ischemic stroke. Each technique operates uniquely on the thrombus, leading to differences in their efficacy. Factors including clot size, clot stiffness, vessel tortuosity, and the angle of interaction between the aspiration catheter and the clot significantly influence these differences. Clinical trials and meta-analyses have shown the overall equivalency of these techniques for the treatments of large vessel occlusion and distal medium vessel occlusions. However, there are nuanced differences that emerge under specific clinical circumstances, highlighting the absence of a one-size-fits-all strategy in acute ischemic stroke management. We emphasize the need for future investigations to elucidate these nuances further, aiming to refine procedural strategies and individualize patient care for optimal outcomes.
Endovascular treatment (EVT) has revolutionized the management of acute ischemic stroke (AIS), but almost half of patients undergoing EVT do not achieve a good outcome. Adjunctive therapies have been proposed to improve the outcomes of EVT in AIS. This review aims to summarize the current evidence on the use of adjunctive therapies in EVT for AIS, including antithrombotic agents, intra-arterial thrombolytics, cerebroprotective agents, normobaric oxygen, and hypothermia. Several adjunctive therapies have shown promise in improving the outcomes of EVT in AIS, but phase 3 clinical trials are needed to establish clinical efficacy. We summarize the advantages and disadvantages of adjunctive EVT treatments and outline the challenges that each of these therapies will face before being adopted in clinical practice.
Since stroke is often associated with cancer, acute stroke patients with cancer undergoing endovascular therapy (EVT) are not uncommon. Reportedly, the proportion of such cases is approximately 6%–7% of all stroke EVT cases. Ischemic stroke in patients with active cancer (cancer-associated stroke) includes not only strokes caused by cancer-related hypercoagulability but also coincident strokes due to common etiologies, strokes associated with tumor emboli, direct tumor invasion of blood vessels, and strokes associated with cancer therapy. Stroke caused by cancer-related hypercoagulability itself encompasses various entities, including paradoxical embolism, stroke due to nonbacterial thrombotic endocarditis, and in situ arterial occlusion due to disseminated intravascular coagulation or thrombotic microangiopathy. Thus, diverse mechanisms contribute to cancer-associated stroke, emphasizing the need to consider individualized treatment strategies for acute cases involving large vessel occlusion. Observational studies have shown that EVT for cancer-associated stroke results in poorer clinical outcomes, but with comparable rates of successful reperfusion and symptomatic intracranial hemorrhage when compared with stroke patients without cancer. This suggests that denying patients EVT solely on the basis of comorbid active cancer is inappropriate, and decision-making should be shared with the patients and their families, preferably through a multidisciplinary team approach. Thrombi retrieved from patients with stroke caused by cancer-related hypercoagulability have unique characteristics, being predominantly platelet rich and difficult to retrieve. Preprocedural imaging and serum biomarkers, including the hyperdense vessel sign on non-contrast CT, susceptibility vessel sign on T2* or susceptibility-weighted MRI, three-territory sign on MRI, and D-dimer levels, are valuable in evaluating the stroke subtype and thrombus features. Thrombectomy techniques, such as contact aspiration and stent retriever monotherapy, have shown varying degrees of effectiveness for stroke caused by cancer-related hypercoagulability, warranting further study. After reperfusion therapy, appropriate treatment for the prevention of stroke recurrence should be initiated, considering the specific stroke subtypes. In conclusion, cancer-associated stroke encompasses diverse subtypes, and thrombi associated with stroke caused by cancer-related hypercoagulability present various challenges for thrombectomy. Individualized treatment approaches based on underlying mechanisms are essential for improving outcomes in acute stroke patients with active cancer. Optimization of preprocedural diagnosis, EVT techniques, and secondary prevention of stroke caused by cancer-related hypercoagulability will lead to better management of these patients and enhance their quality of life.