Posterior Cerebral Artery Involvement in Paediatric Moyamoya: Angiographic Patterns and Stroke Burden

Introduction: The posterior circulation is frequently overlooked when managing patients with moyamoya angiopathy, particularly the non-Asian population. This study aimed to identify the presence of angiopathy in the posterior cerebral artery (PCA), its patterns, and the consequences thereof in a paediatric cohort.

Retrospective clinical data, MRI scans, and cerebral angiograms of all patients referred to a single centre for cerebral revascularization were analysed for PCA involvement. Angiographic patterns of PCA involvement were defined. Associated stroke burden was evaluated using general estimation equation regression models adjusting for prespecified potential confounder age at onset, right or left laterality, and involvement of anterior circulation.

PCA involvement was observed in 37% of 122 patients and was identified to be either proximal (proximal P1 segment, P1-posterior communicating artery [Pcomm] segment) or distal (Pcomm-P2 segment and distal P2 segment and beyond). Distal P2 (32%) and involvement of the entire PCA (26%) were most frequently observed. The odds of having any stroke (anterior distribution, i.e., anterior cerebral artery, middle cerebral artery, or posterior distribution, i.e., PCA) was five times higher (odds ratio [OR] 5.0, 95% CI [2.3, 10.9], p < 0.0001) when PCA was involved compared to without PCA involvement. Distal PCA involvement was observed in 59% of children <2 years of age. The OR of stroke in the PCA distribution with distal PCA involvement compared to proximal involvement was 4.1 (95% CI [0.9, 19.0], p = 0.07). The OR of anterior distribution stroke with Pcomm involvement versus no Pcomm involvement was 6.2 (95% CI [1.0, 37.2], p = 0.05).

Involvement of the PCA in moyamoya children is highlighted. This may be proximal, distal, or along the entire course of the PCA and is strongly associated with overall stroke. The odds of PCA territory strokes is higher with distal PCA involvement, while involvement of the Pcomm plays a more important role in anterior stroke. Younger children are at higher risk of PCA stroke.