Efficacy of prophylactic blood pressure lowering according to a standardized postoperative management protocol to prevent symptomatic cerebral hyperperfusion after direct revascularization surgery for moyamoya disease

Background: Cerebral hyperperfusion is a potential complication of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis for moyamoya disease, but the optimal postoperative management has not been determined. Aggressive blood pressure lowering is controversial because of the risk of ischemic complications. Objective: To establish the optimal postoperative management protocol to prevent symptomatic cerebral hyperperfusion in moyamoya disease. Methods: N-isopropyl-p-[ ¹²³I]-iodoamphetamine single-photon emission computed tomography was performed 1 and 7 days after STA-MCA anastomosis on 152 hemispheres from 108 consecutive patients with moyamoya disease (2-69, mean 33.3 years). Between 2004 and 2007 (period 1), 65 patients were maintained under normotensive conditions after 93 operations, and only patients with cerebral hyperperfusion underwent blood pressure lowering. Between 2008 and 2010 (period 2), all 43 patients were prospectively subjected to intensive blood pressure lowering (<130 mm Hg of systolic blood pressure) immediately after 59 operations. Then the incidence of symptomatic cerebral hyperperfusion was compared between the two groups. Results: Systolic blood pressure the day after surgery was significantly lower in period 2 (mean, 120.9 mm Hg) than in period 1 (133.9 mm Hg) (p < 0.0001). Symptomatic cerebral hyperperfusion was seen in 22 patients during period 1 (23 hemispheres, 24.7%), but only in 4 patients during period 2 (6.7%, p = 0.0047). Multivariate analysis revealed that prophylactic blood pressure lowering was significantly associated with the prevention of symptomatic cerebral hyperperfusion (p = 0.015). Symptomatic cerebral hyperperfusion was relieved in all patients without developing a permanent neurological deficit due to cerebral hyperperfusion. Conclusion: Prophylactic blood pressure lowering prevents symptomatic cerebral hyperperfusion after STA-MCA anastomosis in patients with moyamoya disease. Accurate diagnosis of cerebral hyperperfusion and blood pressure lowering, and considering the severity of hemodynamic compromise in the contralateral and/or remote areas are essential for postoperative management of moyamoya disease.