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Extracranial-Intracranial Bypass To Reduce the Risk of Ischemic Stroke

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Title: Extracranial-Intracranial Bypass To Reduce the Risk of Ischemic Stroke

Agency: Agency for Health Care Policy and Research/Center for Health Care Technology (formerly the Office of Health Technology Assessment)

Contact: Thomas V. Holohan, M.D.

Status: Technology Assessment: Published, 1990

Language: English

Primary Objective: To evaluate the safety, efficacy, and clinical effectiveness of extracranial-intracranial bypass to prevent stroke.

Methods used: Review of published medical literature.

Data identification: Published articles in the English language. A MEDLINE search of the National Library of Medicine using search terms "extracranial-intracranial bypass" and "stroke" was completed; information was also solicited from other agencies of the Public Health Service. A Federal Register notice was also published soliciting information from the medical community at large.

Study Selection: Published articles which addressed the issue of the effectiveness of EC-IC bypass in the prevention of stroke were selected. Thirteen case series encompassing 1,464 patients and one prospective, randomized control trial of 1,377 patients were found.

Data extraction: Type of study, sample size, patient selection criteria, controls (historical or randomized), comparison of outcomes of operated patients versus historical or randomized controls.

Key findings: The surgical case series provided insufficient information to precisely characterize the operated patients, and most contained inadequate data for followup determination of the frequency of postoperative stroke; the historical annual stroke rates to which the operated cases were compared varied between 3% and 25%, and the concomitant effect of antiplatelet drugs was not addressed. Operative stroke and mortality rates did not differ from those in the prospective trial. The multicenter cooperative randomized trial demonstrated that at 56 months of followup the annualized stroke rates were 6.2% for medically treated patients and 6.6% for operated patients.

Conclusions: There are no reliable objective data which indicate that there exists a group of patients in whom EC-IC bypass reduces the rate of stroke compared to patients managed medically. The results of the single prospective randomized trial must be accepted as the best medical evidence currently available.

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