Abstract 15: Preoperative Transdural Collaterals in Moyamoya
Introduction: The prevalence of angiographically evident pre-operative transdural collaterals to the brain in moyamoya is not well documented. Hypothesis: We hypothesized that presence of transdural collaterals would be associated with more advanced moyamoya disease at diagnosis, more frequent operative complications and better long-term angiographic results. Methods: Single institution case series reviewing all moyamoya patients with 6 vessel arteriograms treated surgically from 2005-2013. Results: 204 patients (n=121 (59%) F / 83 (41%) M) were diagnosed with moyamoya at 9.5 years of age (range 0.4-35 years). Presentation included ischemia (84% stroke or TIA), headache (36%), incidental (7%), chorea (3%) and hemorrhage (1%). Radiographically, 154 (75%) had bilateral disease for a total of 358 affected hemispheres, 152 (75%) had radiographic stroke and 190 (93%) had ivy sign on FLAIR MRI, indicating slow flow. Of the 358 hemispheres, 324 were treated operatively. On preoperative angiogram, 99 patients (49%) had transdural collaterals in 174 affected hemispheres (54%). Suzuki grades were higher in patients with collaterals (3.4 vs. 3.0, p=0.002). Of a total of 324 treated hemispheres, 84 (26%) had collaterals within the area of the surgical field. Complications included 12 strokes (3.7% stroke rate per hemisphere), with 5 (42%) directly attributable to interruption of a transdural collateral. In one-year postoperative arteriograms in 215 hemispheres, while not significant, Matsushima grades trended better in patients with preoperative collaterals, (1.6 vs. 1.8; A=1, B=2, C=3, p=0.09). Conclusions: In conclusion, transdural collaterals are present in nearly half of all moyamoya patients. They are more common in advanced disease, are associated with stroke as a perioperative complication and may suggest increased capacity to produce surgical collaterals postoperatively. These data support the utility of preoperative arteriograms.