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Extracranial-intracranial bypass surgery for stroke prevention in hemodynamic cerebral ischemia: the Carotid
William J Powers1, William R Clarke, Robert L Grubb
1Department of Neurology, Box 7025, Room 2131, 170 Manning Dr, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. powersw@neurology.unc.edu
Insights
Extracranial-intracranial bypass surgery did not reduce stroke risk in patients with carotid artery occlusion. Medical therapy alone showed similar outcomes over two years, with bypass surgery increasing short-term stroke risk.
Area of Science:
- Neurology
- Neurosurgery
- Vascular Surgery
Background:
- Patients with symptomatic atherosclerotic internal carotid artery occlusion (AICAO) and hemodynamic cerebral ischemia face high stroke risk with medical treatment.
- This study evaluated the efficacy of EC-IC bypass surgery in preventing recurrent strokes in this high-risk population.
Purpose of the Study:
- To test if adding extracranial-intracranial (EC-IC) bypass surgery to best medical therapy reduces subsequent ipsilateral ischemic stroke in patients with recently symptomatic AICAO and hemodynamic cerebral ischemia.
- To assess the safety and efficacy of EC-IC bypass in preventing stroke in a specific patient cohort.
Main Methods:
- A parallel-group, randomized, open-label, blinded-adjudication clinical trial involving 195 patients across 49 clinical and 18 PET centers.
- Patients with confirmed AICAO, recent hemispheric symptoms, and hemodynamic cerebral ischemia (identified by PET) were randomized to EC-IC bypass surgery plus medical therapy or medical therapy alone.
- The primary endpoint was a composite of stroke and death within 2 years, with a 30-day perioperative assessment.
Main Results:
- The trial was terminated early due to futility. The 2-year primary endpoint rates were 21.0% for the surgical group and 22.7% for the nonsurgical group (P = .78).
- There was no significant difference in the 2-year stroke risk between the EC-IC bypass and medical therapy groups.
- However, the 30-day rate of ipsilateral ischemic stroke was significantly higher in the surgical group (14.4%) compared to the nonsurgical group (2.0%).
Conclusions:
- EC-IC bypass surgery, when added to best medical therapy, did not reduce the risk of recurrent ipsilateral ischemic stroke at 2 years in patients with symptomatic AICAO and hemodynamic cerebral ischemia.
- The findings suggest that EC-IC bypass surgery is not beneficial for this patient population and carries an increased risk of perioperative stroke.
Context:
Patients with symptomatic atherosclerotic internal carotid artery occlusion (AICAO) and hemodynamic cerebral ischemia are at high risk for subsequent stroke when treated medically.
Objective:
To test the hypothesis that extracranial-intracranial (EC-IC) bypass surgery, added to best medical therapy, reduces subsequent ipsilateral ischemic stroke in patients with recently symptomatic AICAO and hemodynamic cerebral ischemia.
Design:
Parallel-group, randomized, open-label, blinded-adjudication clinical treatment trial conducted from 2002 to 2010.
Setting:
Forty-nine clinical centers and 18 positron emission tomography (PET) centers in the United States and Canada. The majority were academic medical centers.
Participants:
Patients with arteriographically confirmed AICAO causing hemispheric symptoms within 120 days and hemodynamic cerebral ischemia identified by ipsilateral increased oxygen extraction fraction measured by PET. Of 195 patients who were randomized, 97 were randomized to receive surgery and 98 to no surgery. Follow-up for the primary end point until occurrence, 2 years, or termination of trial was 99% complete. No participant withdrew because of adverse events.
Interventions:
Anastomosis of superficial temporal artery branch to a middle cerebral artery cortical branch for the surgical group. Antithrombotic therapy and risk factor intervention were recommended for all participants.
Main Outcome Measure:
For all participants who were assigned to surgery and received surgery, the combination of (1) all stroke and death from surgery through 30 days after surgery and (2) ipsilateral ischemic stroke within 2 years of randomization. For the nonsurgical group and participants assigned to surgery who did not receive surgery, the combination of (1) all stroke and death from randomization to randomization plus 30 days and (2) ipsilateral ischemic stroke within 2 years of randomization.
Results:
The trial was terminated early for futility. Two-year rates for the primary end point were 21.0% (95% CI, 12.8% to 29.2%; 20 events) for the surgical group and 22.7% (95% CI, 13.9% to 31.6%; 20 events) for the nonsurgical group (P = .78, Z test), a difference of 1.7% (95% CI, -10.4% to 13.8%). Thirty-day rates for ipsilateral ischemic stroke were 14.4% (14/97) in the surgical group and 2.0% (2/98) in the nonsurgical group, a difference of 12.4% (95% CI, 4.9% to 19.9%).
Conclusion:
Among participants with recently symptomatic AICAO and hemodynamic cerebral ischemia, EC-IC bypass surgery plus medical therapy compared with medical therapy alone did not reduce the risk of recurrent ipsilateral ischemic stroke at 2 years.
Trial Registration:
clinicaltrials.gov Identifier: NCT00029146.
