Superficial Temporal Artery Size Changes After Encephaloduroarteriosynangiosis for the Treatment of Moyamoya Disease

Background and objective: Surgery is the mainstay of stroke prevention in patients with symptomatic moyamoya disease (MMD). We present the results of a single-center retrospective study of indirect revascularization surgery for adult MMD, emphasizing angiographic outcomes, including dilation of the superficial temporal artery and formation of new collaterals.

Methods: A prospectively maintained database of procedures performed for MMD was reviewed. Adult patients treated with indirect revascularization and with long-term angiographic follow-up were included. Preoperative and postoperative angiographic images and baseline and procedural characteristics were analyzed. A Wilcoxon signed-rank test was used to test the hypothesis that the superficial temporal artery increases in diameter postoperatively.

Results: We identified 40 hemispheres in 27 patients, of which 35 had a sufficient angiographic follow-up. Bilateral procedures were performed on 16 patients. Most patients were female (72.5%), with a median age of 43 years old. The most common clinical presentation was ischemic stroke in 59.3% of cases. All patients underwent an encephaloduroarteriosynangiosis for treatment. A follow-up angiogram was performed at a median of 13.8 months postoperatively, showing superficial temporal artery (STA)-derived collaterals in 71.4% and collateral ingrowth via the burr holes in 61.8% of cases. Disease progression was evident in 34.3% of hemispheres. The normalized STA diameter was significantly increased postoperatively (2.4 to 3 mm; P < 0.05). A univariate analysis revealed that transdural collaterals and hyperlipidemia may affect collateral ingrowth from the STA, and no other patient- or procedure-related factors, including replacement of the bone flap, impacted on this.

Conclusions: A significant increase in STA diameter on follow-up angiography after encephaloduroarteriosynangiosis was found; however, this was not directly associated with STA collateral development. Rates of postoperative transient ischemic attacks were low, and no patients had a new ischemic or hemorrhagic stroke at last follow-up. The presence of transdural collaterals and the absence of hyperlipidemia were associated with STA collateral development on follow-up angiography, but the causality of this finding is unclear.