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Updated: May 26, 2026
Optimized Management of Endovascular Treatment for Acute Ischemic Stroke
Published on: January 18, 2018
Bypass for the prevention of ischemic stroke
Ana Rodríguez-Hernández1, S Andrew Josephson, Andrew S Josephson
1Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA.
Insights
Extracranial-intracranial bypass surgery for hemodynamic ischemic stroke lacks proven benefit despite low complication rates. Patient selection based on hemodynamic insufficiency is crucial, but evidence remains controversial, requiring individualized treatment decisions.
Area of Science:
- Neurosurgery
- Vascular Surgery
- Neurology
Background:
- Ischemic strokes are often thromboembolic, but some stem from hemodynamic issues, potentially requiring surgical intervention.
- Extracranial-intracranial bypass techniques, including superficial temporal artery-to-middle cerebral artery (MCA) bypass, have been developed for such cases.
- The clinical indications and efficacy of these surgical procedures remain subjects of debate.
Purpose of the Study:
- To review current practices and assess the clinical indications and efficacy of bypass surgery for hemodynamic ischemic stroke.
- To examine the role of objective measures in patient selection for surgical intervention.
- To synthesize evidence from clinical trials and observational studies regarding bypass surgery outcomes.
Main Methods:
- Review of surgical series, systematic literature reviews, and randomized clinical trials.
- Evaluation of diagnostic techniques for hemodynamic insufficiency, such as xenon-enhanced computed tomography (CT) with acetazolamide challenge and positron emission tomography (PET).
- Analysis of patient selection criteria, surgical techniques, and postoperative outcomes.
Main Results:
- Bypass surgery has a reported morbidity rate under 5% and a patency rate exceeding 95%.
- The Extracranial-Intracranial Bypass Trial highlighted the importance of selecting patients based on objective hemodynamic insufficiency measures.
- Despite advancements in diagnostic techniques, randomized trials have yielded contradictory results regarding the clear benefit of bypass surgery.
Conclusions:
- Patients with athero-occlusive disease and hemodynamic insufficiency face a significant stroke risk if untreated.
- Current evidence supporting the efficacy of surgical intervention for hemodynamic ischemic stroke is insufficient.
- Individualized management decisions are necessary pending further data and consensus on the role of bypass surgery.
Objective:
Although most ischemic strokes are thromboembolic in origin and their management is endovascular or medical, some are hemodynamic in origin and their management may be surgical. Extracranial-intracranial bypass with superficial temporal artery-to-middle cerebral artery (MCA) bypass, high-flow interposition grafts, and reconstructive techniques have been developed. Clinical indications and efficacy are controversial, and this review examines current practices.
Methods:
Bypass surgery is indicated for patients with athero-occlusive disease that results in chronic, low cerebral blood flow accompanied by episodes of ischemic symptoms. Specific diagnoses include: (1) internal carotid artery occlusion; (2) MCA occlusion and, rarely, high-grade MCA stenosis; (3) vertebrobasilar atherosclerotic steno-occlusive disease; (4) vasculitis resulting in severe occlusive disease; and (5) moyamoya disease.
Results:
Discouraging results from the Extracranial-Intracranial Bypass Trial demonstrated the importance of selecting surgical patients based on objective measures of hemodynamic insufficiency. Two such tests are xenon-enhanced computed tomography with acetazolamide challenge and positron emission tomography with measurement of oxygen extraction fraction. Perfusion computed tomography may be another, more practical test. Surgical series, systematic reviews of the literature, and two new randomized clinical trials that use these diagnostic techniques reveal contradictory results. Although they demonstrate that bypass surgery has a morbidity rate of less than 5% and a patency rate of more than 95%, they have not proven a clear benefit.
Conclusions:
Patients with athero-occlusive disease and symptoms of hemodynamic insufficiency have significant risk of stroke if left untreated or managed medically. On the other hand, surgical intervention lacks supporting evidence. Clinicians must individualize their management recommendations until additional data are published or further consensus develops.
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