Introduction: Moyamoya is usually a progressive disorder, characterized by gradual stenosis of the bilateral supraclinoid internal carotid arteries (ICAs) and proximal middle and anterior cerebral arteries (MCAs, ACAs). Given its ability to restore hemispheric blood flow, surgical revascularization constitutes the most effective means of secondary stroke prevention in symptomatic moyamoya patients. However, while revascularization surgery improves cerebral blood flow, it has not been shown to impact the progression of steno-occlusive changes in moyamoya.
Methods: Case report and literature review.
Results: A 70-year old woman with bilateral symptomatic moyamoya disease underwent indirect cerebral revascularization (encephalo-duro-arterio-synangiosis) on the left side followed by combined direct-indirect revascularization (STA-MCA bypass and encephalo-duro-synangiosis) on the right side. Following these uneventful and technically successful procedures, effective revascularization of both MCA territories was demonstrated on angiography. As a result, the patient experienced significant clinical improvement with complete resolution of her transient ischemic attacks. However, on her last follow-up angiogram, 6 months after the right-sided procedure, significant improvement of the caliber of the M1 segment of the right MCA and regression of the moyamoya vessels was observed.
Conclusions: Regression of steno-occlusive changes in moyamoya following revascularization surgery has not been previously reported. Whether the observed phenomenon represents a self-remitting disease manifesting as moyamoya syndrome, a spontaneously recanalized intraluminal thrombus, or a direct hemodynamic effect of cerebral revascularization, remains to be seen.
Patient Care: This report reminds neurosurgeons managing moyamoya patients to pay close attention not only to the patency of the bypass but also to the dynamic changes in the underlying vasculopathy when reviewing follow-up cerebral angiograms.
Learning Objectives: 1. Recognize that direct and indirect cerebral revascularization procedures improve hemispheric blood flow in moyamoya patients, but do not usually impact the progression of intracranial steno-occlusive changes.
2. Recognize that spontaneous regression of angiographic moyamoya features, including steno-occlusive changes, may exceptionally occur.