Evaluation of long-term prognosis and cerebral blood flow in adult patients with moyamoya disease with and without vascular reconstructive surgery

Abstract

We retrospectively studied 27 adult patients (male 9, female 18) with moyamoya disease, with and without vascular reconstructive surgery, with respect to angiographical finding, regional cerebral blood flow (rCBF) and long-term prognosis. Initial episodes involved intracranial hemorrhage in 20 cases (74%), ischemia in 6 cases and incidental detection in 1 case. Of 14 non-revascularization cases, 9 patients (64%) bled during 9 years follow-up. The recurrent bleeding rate in 10 cases of the hemorrhage type excluding aneurysm cases was calculated to be as high as 65% for 10 years. In the final outcome, 10 patients (71%) showed a poor prognosis including 5 who died due to rebleeding. The rCBF measured by 133Xe SPECT in the bilateral middle cerebral artery territory of 6 patients revealed 41±15 ml/100 g/min at rest and 48±18 ml/100 g/min after acetazolamide loading, indicating a percent increase of 20±22%. Thirteen cases were surgically treated on 22 hemispheric sides, by direct bypass (7 sides) and indirect bypass (15 sides) surgery. Postoperative angiogram demonstrated good neovascularization from the external carotid artery in 15 hemispheric sides (68%); all sides of direct procedure and half the sides of indirect procedure. Of these 15 sides, 14 sides (93%) showed reduction of moyamoya vessels fed by the internal carotid artery. Only 1 patient (8%) among 13 cases undergoing revascularization bled during 5-year follow-up and the other 12 patients returned to their previous jobs. The rCBF measured in the area fed from the bypass circuit in 18 hemispheres of 11 patients was preoperatively. 48±9 ml/100 g/min at rest and 53±15 ml/100 g/min after acetazolamide loading, indicating a percent increase of 8±17%. Postoperative study revealed the resting and loading rCBF significantly increased by around 30% to 60±6 and 70±9 ml/100 g/min, respectively, indicating a percent increase of 16±8%. Thus, vascular reconstructive surgery is recommended for adult patients with moyamoya disease, since the long-term prognosis of non-surgical cases is poor due to recurrent bleeding and surgery tends to inhibit recurrence of bleeding. The development of good collaterals from implanted external carotid artery can improve the cerebral blood flow and vascular reactivity at the bypass site leading to reduction of hemodynamic stress on basal moyamoya vessels. For this purpose, direct bypass surgery seems to be superior to indirect bypass surgery.