Significance of Quantitative Cerebral Blood Flow Measurement in the Acute Stage after Revascularization Surgery for Adult Moyamoya Disease: Implication for the Pathological Threshold of Local Cerebral Hyperperfusion

Abstract

Objective: Superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis is a standard surgical procedure for adult patients with moyamoya disease (MMD) and plays a role in preventing ischemic and/or hemorrhagic stroke. Cerebral hyperperfusion (CHP) syndrome is a potential complication of this procedure that can result in deleterious outcomes, such as delayed intracerebral hemorrhage, but the exact threshold of the pathological increase in postoperative cerebral blood flow (CBF) is unclear. Thus, we analyzed local CBF in the acute stage after revascularization surgery for adult MMD to predict CHP syndrome under modern perioperative management. Materials and Methods: Fifty-nine consecutive adult MMD patients, aged 17–66 years old (mean 43.1), underwent STA-MCA anastomosis with indirect pial synangiosis for 65 affected hemispheres. All patients were perioperatively managed by strict blood pressure control (systolic pressure of 110–130 mm Hg) to prevent CHP syndrome. Local CBF at the site of anastomosis was quantitatively measured using the autoradiographic method by N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography 1 and 7 days after surgery, in addition to the preoperative CBF value at the corresponding area. We defined CHP phenomenon as a local CBF increase over 150% compared to the preoperative value. Then, we investigated the correlation between local hemodynamic change and the development of CHP syndrome. Results: After 65 surgeries, 5 patients developed CHP syndrome, including 2 patients with delayed intracerebral hemorrhage (3.0%), 1 with symptomatic subarachnoid hemorrhage (1.5%), and 2 with focal neurological deterioration without hemorrhage. The CBF increase ratio was significantly higher in patients with CHP syndrome (270.7%) than in patients without CHP syndrome (135.2%, p = 0.003). Based on receiver operating characteristic analysis, the cutoff value for the pathological postoperative CBF increase ratio was 184.5% for CHP syndrome (sensitivity = 83.3%, specificity = 94.2%, area under the curve [AUC] value = 0.825) and 241.3% for hemorrhagic CHP syndrome (sensitivity = 75.0%, specificity = 97.2%, AUC value = 0.742). Conclusion: Quantitative measurement of the local CBF value in the early postoperative period provides essential information to predict CHP syndrome after STA-MCA anastomosis in patients with adult MMD. The pathological threshold of hemorrhagic CHP syndrome was as high as 241.3% by the local CBF increase ratio, but 2 patients (3.0%) developed delayed intracerebral hemorrhage in this series that were managed following the intensive perioperative management protocol. Thus, we recommend routine CBF measurement in the acute stage after direct revascularization surgery for adult MMD and satisfactory blood pressure control to avoid the deleterious effects of CHP.

Matching Selection of Donor-Recipient Vessels in Revascularization Surgery Effectively Reduce the Incidence of Postoperative Hyperperfusion Syndrome in Adult Moyamoya Disease: A Retrospective Comparison Study

“…All patients gradually recovered from anesthesia in the neurosurgical intensive care unit with strict blood pressure monitoring and controlled to 120–130 mm Hg [10, 11]. Antiplatelet therapy and a hydration protocol were routinely administered for all the patients.…”

Prediction of Cerebral Hyperperfusion after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis by Three-Dimensional-Time-of-Flight Magnetic Resonance Angiography in Adult Patients with Moyamoya Disease

“…MRI included diffusion-weighted images (DWI), T2-weighted images, T2*-weighted images, and fluid-attenuated inversion recovery (FLAIR). We quantitatively measured the CBF, and a small region of interest (ROI) with a diameter of 1 cm was defined manually at the site of anastomosis and the ipsilateral cerebellar hemisphere according to the previously described method [15][16][17]. The exact sites of anastomosis were confirmed by the original axial slice on MRA.…”

“…The exact sites of anastomosis were confirmed by the original axial slice on MRA. To calculate the postoperative/preoperative CBF ratio, both preoperative and postoperative CBF were adjusted to the CBF value of the ipsilateral cerebellar hemisphere on POD 1 [15][16][17].…”

“…The definition of radiological local CHP in this study included all of the following items described previously: (1) a 150% increase in CBF at the site of anastomosis, (2) visualization of STA-MCA bypass by MR angiography, and (3) the absence of other pathologies, such as compression of the brain surface by the temporal muscle inserted for indirect pial synangiosis, and ischemic changes [16,17]. Then, we diagnosed the patients with CHP syndrome if they developed delayed symptomatic hemorrhage (intracerebral hemorrhage and/or subarachnoid hemorrhage) at the region of local CHP, seizure in the presence of local CHP, and/or neurological deterioration caused by local CHP that was able to be ameliorated by reducing the blood pressure.…”

“…We routinely administered antiplatelet agents (100 mg of aspirin/day) starting the day after surgery to all patients. If patients developed radiological CHP, we attempted further blood pressure reduction (systolic blood pressure of 100-120 mm Hg) and administered additional levetiracetam (1,000 mg/day) and edaravone (60 mg/day) until 7 days after surgery [17,21]. Based on the temporal profile of 123 I-IMP-SPECT and MRI/ MRA findings, we gradually allowed the return to normotensive conditions within 7-10 days after surgery [19,20].…”