STA-MCA Bypass for Symptomatic Moyamoya Disease – Lessons Learnt from 89 Revascularisations

Introduction: Efficacy of surgical revascularisation procedures over conservative management in moyamoya-disease (MMD) is well established. However there is dearth of literature on comprehensive evaluation of impact of age and Suzuki staging on clinical and angiographic outcome in symptomatic MMD patients undergoing direct revascularisation (DR) via superficial temporal artery – middle cerebral artery (STA-MCA) bypass. Study objective was to comprehensively evaluate clinical and angiographic outcome in symptomatic MMD patients undergoing STA-MCA bypass.

Methods: We analysed consecutive MMD patients who underwent direct-revascularisation (DR) via STA-MCA bypass. Primary outcome measures were mRS scale and stroke risk reduction. Secondary outcome measure was angiographic outcome score (AOS).

Results: 70 patients (89 DR procedures), including 37.9% adults (>18yr), were operated over a duration of 8 years and followed up for 2 years (mean). Long-term bypass-patency rates were deemed 83.3% and 88.8% in children and adults respectively. In pediatric age group, median mRS scores improved from 3 to 2 (p=0.001), 97.3% were free of recurrent strokes and AOS scores improved significantly (p=0.002). Amongst adult MMD patients, median mRS score marginally improved from 3 to 2 (p=0.25), 100% were free of recurrent strokes and AOS improved significantly (p=0.02). On comparing pediatric and adult patients, improvement in mRS scores (p=0.14) and AOS scores (p=0.65) were similar across the two age groups. Overall late stage MMD patients (Suzuki stages IV-VI) showed better improvement in mRS scores when compared with early stage MMD patients (Suzuki stages I-III; p=0.04). Recurrent stroke rates were similar in both groups (p=0.26). AOS scores improved significantly in both early and late stage MMD (p < 0.001 in both), though the improvement amongst the two groups was similar (p=0.88).

Conclusion : Using meticulous surgical technique, excellent long-term bypass patency rates can be achieved to facilitate optimal clinical and angiographic outcome in symptomatic MMD patients, irrespective of the age group and stage of disease.