References for this Review were identified by a search of PubMed with the terms “ischaemic stroke”, “MERCI”, “thrombectomy”, “thrombolysis”, “diffusion–perfusion mismatch”, “CT-perfusion”, and “clinical–diffusion mismatch”. Searches covered the period between 1966 and August, 2007. Only studies published in English were reviewed. Particular focus was given to reports of randomised clinical trials, safety and efficacy studies, and prospective registries that have been presented at multiple
ReviewEndovascular treatment of acute ischaemic stroke
Introduction
Stroke therapy is in some ways similar to the treatment of coronary artery disease; for example, intravenous alteplase (tissue plasminogen activator; tPA) given within 3 hours for thrombolytic treatment of acute ischaemic stroke has been used for more than 10 years.1 However, although certain common features of occlusive vascular disease have enabled the extension of some of the treatments for acute myocardial infarction to acute ischaemic stroke, the differences have led to a fork in the road. Over the past decade, the treatment of acute myocardial infarction has moved away from systemic thrombolysis towards percutaneous coronary interventions.2, 3, 4, 5 By contrast, neuroendovascular interventions, which include procedures such as local intra-arterial thrombolysis and the mechanical removal of in situ thrombi, are still mostly reserved for patients with acute ischaemic stroke who cannot be safely given systemic thrombolysis. Alteplase might be less effective for treating occlusions of the large vessels, such as the internal carotid artery or middle cerebral artery, with estimated recanalisation rates of 0–33% based on transcranial Doppler of these vessels.6, 7, 8 Endovascular treatments for acute ischaemic stroke require validation from large-scale, randomised, controlled clinical trials; however, because these therapies are unproven, direct comparisons with alteplase for patients with acute ischaemic stroke in blinded studies are difficult—physicians are reluctant to randomly assign eligible patients away from a proven treatment. By contrast, in the specialty of cardiology, the success of angioplasty has helped the comparison of percutaneous coronary interventions with currently accepted treatment strategies.2, 5, 9 Despite these problems, investigations to validate endovascular therapies for acute ischaemic stroke are of paramount importance, in view of the low overall number of patients with acute ischaemic stroke who qualify for treatment with alteplase.10, 11
In this Review, we summarise randomised trials, some registries of local intra-arterial thrombolysis, mechanical thrombectomy and other mechanical treatments for the treatment of acute ischaemic stroke, and advanced imaging techniques as alternative ways to identify candidates for therapies based on widened therapeutic windows.
Section snippets
Local intra-arterial thrombolysis
An alternative regimen to systemic thrombolysis for use beyond 3 hours after the onset of symptoms is to give a lower dose of local intra-arterial thrombolysis, which gives targeted drug effects and clot dissolution without the risk of extracranial or intracranial haemorrhage associated with delayed systemic thrombolysis. Several case reports and series were published before the feasibility of this therapeutic option was assessed in large-scale studies,12, 13, 14, 15, 16, 17 and each of these
Systemic and local intra-arterial thrombolysis
In view of the resistance of proximal thrombi to intravenously given thrombolytics, combined therapy has the benefit of systemic thrombolysis with increased activity at the site of the clot. Since the publication of the NINDS tPA trial,1 which defined alteplase as an efficacious treatment for acute ischaemic stroke, recent studies seldom report the random assignment of patients away from this drug. However, the phase I Emergency Management of Stroke (EMS) trial,21 which tested the efficacy,
Mechanical or non-pharmacological methods of revascularisation
Devices have been developed to remove clots from the coronary vasculature, although they have mostly been replaced by angioplasty. However, in patients with acute ischaemic stroke, great emphasis has been placed on these interventions, which include mechanical thrombectomy (clot removal) and mechanical disruption of the clot. The Concentric retriever (Concentric Medical, Mountainview, CA, USA), which was granted approval by the US Food and Drug Administration in 2003, consists of a
Increased treatment windows
One of the greatest problems in the treatment of acute ischaemic stroke is the restricted time window during which reperfusion therapy can be safely given. Although early studies of systemic thrombolytics and local intra-arterial thrombolysis used triage criteria based on non-contrast CT data, MRI and perfusion imaging of the ischaemic penumbra might be an alternative means to identify candidates suitable for revascularisation therapy. When triage criteria based only on CT data are
Clinical criteria and selection of patients
Although there are no standardised guidelines for the endovascular treatment of acute ischaemic stroke, several studies have uniform inclusion and exclusion criteria. These criteria restrict endovascular treatment to patients who are ineligible for treatment with alteplase, such as those who present later than 3 hours after the onset of symptoms or those prevented from taking systemic thrombolysis.1 PROACT I, PROACT II, and the EMS bridging trial provide data on the safety of local
Practitioners of interventional neurology
The rapid progress in the interventional management of stroke is indicative of advances in the specialty in general. Clinicians who have previously provided only the more traditional modes of therapy have expressed interest in the new ways to treat diseases that previously could only be treated with medical or open surgical techniques. Although the first cerebral angiogram was done by the neurologist Egaz Moniz more than 50 years ago by direct carotid puncture, refinements in the transfemoral
Conclusions
A decade after the use of systemic thrombolysis for the treatment of acute ischaemic stroke, we now enter an era of newer endovascular treatments, in which intra-arterial thrombolysis and mechanical methods of thrombectomy and thrombus disruption are being investigated. Although these therapies have higher recanalisation rates compared with systemic thrombolysis, they are still limited by their availability, and we await the results of forthcoming randomised trials to validate these therapies.
Search strategy and selection criteria
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Cited by (19)
Ischemic stroke
2011, Radiologic Clinics of North AmericaCitation Excerpt :Neuroendovascular interventions, which include procedures such as local intra-arterial thrombolysis and the mechanical removal of thrombus, are largely reserved for acute ischemic stroke patients who cannot safely receive (ie, present outside of the 3–4.5 hour time window), or who have failed intravenous rtPA therapy, and in whom imaging has shown a large region of potentially salvageable tissue. A complete review of these interventions is beyond the scope of this article, however, interested readers are referred to recent reviews by Janjua and Brisman78 and Nogueira and colleagues.79,80 Although guidelines for the endovascular treatment of acute ischemic stroke vary largely by institution, general inclusion and exclusion criteria have been established by large clinical trials.
Endovascular treatment and intra-arterial thrombolysis in acute ischemic stroke
2010, Medicina IntensivaAcute ischemic stroke after percutaneous cardiac intervention in an elderly patient
2010, International Journal of GerontologyCritical Care Management of Subarachnoid Hemorrhage and Ischemic Stroke
2009, Clinics in Chest MedicineCitation Excerpt :After the administration of IV t-PA, patients should be monitored in an ICU, with strict control of blood pressure to below 185/105 mm Hg and control of hyperglycemia to prevent hemorrhagic conversion.81 Patients with suspected large vessel infarctions are often referred urgently for cerebral angiography after IV thrombolytic therapy is given to diagnose and treat persistent large vessel occlusions, a management strategy referred to as “bridging therapy.”87,88 Newer neuroimaging techniques can demonstrate the state of vessel patency and tissue perfusion and viability.
A thromboembolic model for the efficacy and safety evaluation of combined mechanical and pharmacologic revascularization strategies
2013, Journal of NeuroInterventional Surgery