Introduction: Superficial temporal artery-middle cerebral artery (STA-MCA) bypass is generally performed as the preferable surgical treatment for moyamoya disease (MMD). Cerebral hyperperfusion (CHP) syndrome and ischemia are potential complications during the acute stage after revascularization for MMD, and their managements are contradictory to each other.

Methods: We retrospectively investigated the incidence of the simultaneous occurrence of CHP and infarction on the same hemisphere after direct revascularization surgery for MMD.

Results: Of the 172 consecutive direct revascularization surgeries performed for MMD, we encountered two adult cases (1.1%) manifesting the simultaneous occurrence of symptomatic CHP and remote infarction on the operated hemisphere in the acute stage. A 47-year-old man initially presenting with infarction developed CHP syndrome (fluctuating aphasia) two days after left STA-MCA bypass, as assessed by quantitative single-photon emission computed tomography (SPECT). Although blood pressure lowering ameliorated his symptoms, he developed cerebral infarction at a remote area on the operated hemisphere in the acute stage. Another 63-year-old man, who initially had progressing stroke, presented with aphasia due to focal CHP in the left temporal lobe associated with acute infarction at the tip of the left frontal lobe one day after left STA-MCA anastomosis, when SPECT showed a paradoxical decrease in cerebral blood flow (CBF) in the left frontal lobe despite a marked increase in CBF at the site of anastomosis. Symptoms were ameliorated in both patients with the normalization of CBF, and there were no further cerebrovascular events during the follow-up period.

Conclusions: Patients with MMD temporarily represent uneven cerebral hemodynamics in the acute stage after STA-MCA bypass. Although the incidence is relatively low, CHP and cerebral infarction could occur simultaneously not only due to blood pressure lowering against CHP, but also to the ‘watershed shift’ phenomenon, which needs to be elucidated in future studies.

Patient Care: Based on our findings, we can attempt more careful peri-operative care of moyamoya disease, by strict blood pressure control with the use of neuroprotective agents including minocycline hydrochloride and/or edaravone.

Learning Objectives: By the conclusion of this session, participants should be able to know uneven cerebral hemodynamics in the acute stage after direct revascularization for adult-onset moyamoya disease.

References: Fujimura M, Shimizu H, Inoue T, et al. Significance of focal cerebral hyperperfusion as a cause of transient neurologic deterioration after EC-IC bypass for moyamoya disease: Comparative study with non-moyamoya patients using 123I-IMP SPECT. Neurosurgery 68: 957-965, 2011. Fujimura M, Niizuma K, Inoue T, et al. Minocycline prevents focal neurological deterioration due to cerebral hyperperfusion after extracranial-intracranial bypass for moyamoya disease. Neurosurgery 74:163-170, 2014. Hayashi T, Shirane R, Fujimura M, Tominaga T. Postoperative neurological deterioration in pediatric moyamoya disease: watershed shift and hyperperfusion. J Neurosurg Pediatr 6: 73-81, 2010.