Effectiveness of Bypass surgery in Treatment and Prevention of Ischemic Symptoms due to Intracranial Arterial Stenosis

Oh, J Y; Choi, W Y; Joo, W I; Cho, C K; Park, H W; Lee, K J; Rha, H K; Park, C K

Abstract

OBJECTIVE
Although extracranial-intracranial(EC-IC) bypass surgery is considered an appropriate treatment in selected cases of cerebrovascular ischemic disease, this procedure can also be associated with significant morbidity, some of which (especially intracranial stenotic lesions) paradoxically may be the direct result of the patent bypass. This study examined the effectiveness of EC-IC bypass surgery in the treatment and prevention of a cerebral infarct from an intracranial arterial stenosis.
METHODS
During the recent 7 years, EC-IC bypass surgery was performed on 90 patients whose cerebrovascular reserve capacity were significantly impaired due to an occlusion or stenosis(over 70%) of the ICA and/or MCA. Of these 90 consecutive patients, 33 patients had a stenosis of the intracranial ICA or MCA. Of these 33 patients, the type of ischemic episode was transient ischemic attack (TIA) in 11, reversible ischemic neurological deficit (RIND) in 9 and a complete stroke in 13.
RESULTS
The postoperative courses were uneventful in 26 cases, temporary neurologic deficit was found in 5, a permanent deficit was encountered in one and focal seizure occurred in one. The bypass patency was confirmed by a postoperative angiogram or MRA in all cases except for one. A postoperative cerebral blood flow study including acetazolimide stimulation showed significant improvement in all cases except for 2 cases (one case with bypass failure and the other with a post-bypass occlusion of the preoperative stenotic segment). During the follow up period after revascularization surgery, there were no further strokes in any patient who had undergone EC-IC bypass surgery. The postoperative long-term follow up angiogram or MRA showed an occlusion of the preoperative stenotic segment in 6 cases, progression in 7, regression in 2 and no change in the remaining 18.
CONCLUSION
In view of these findings, ECIC bypass surgery on a stenotic lesion of the intracranial ICA or MCA is effective andnot dangerous despite possibility of a post-bypass occlusion of the stenotic lesion. Therefore, the authors conclude that EC-IC bypass surgery constitutes an appropriate treatment for a subgroup of patients with an intracranial arterial stenosis.