Delayed intracerebral hemorrhage after superficial temporal artery-middle cerebral artery anastomosis in a patient with moyamoya disease: possible involvement of cerebral hyperperfusion and increased vascular permeability

Background: Postoperative intracerebral hemorrhage is a rare complication after surgical revascularization for moyamoya disease, and its mechanism is totally undetermined. Case Description: A 47-year-old woman with moyamoya disease, experiencing crescendo transient ischemic attack on her left hand, underwent STA-MCA anastomosis on the right hemisphere. Postoperative MR imaging 1 day after surgery demonstrated asymptomatic vasogenic edema without ischemic change at the subcortex under the site of the anastomosis that expanded the next day, and STA-MCA bypass was apparently patent with the strong high signal by MR angiography. N-isopropyl-p-[¹²³I]iodo-amphetamine single-photon emission CT showed marked increase in the CBF on the hemisphere operated on. Four days after surgery, the patient complained of sudden headache and experienced severe monoparesis in her left hand due to the intracerebral hemorrhage at the corresponding lesion to the prior vasogenic edema. Edema around hematoma was prolonged for as long as a month; while intensive blood pressure control and the use of adrenocorticosteroid gradually relieved her symptoms. The patient completely recovered from her symptoms 2 months later, and she was discharged without neurologic deficit. Her transient ischemic attacks completely disappeared postoperatively. Conclusion: Early increase in CBF associated with vasogenic edema formation at the site of the anastomosis could be the warning sign for subsequent hemorrhagic complication, and intensive blood pressure control is warranted in such patients. Alternatively, it would be necessary to elucidate the biochemical mechanism of the deleterious cascade during reperfusion in moyamoya disease to avoid this rare complication.