Long-term cognitive changes after revascularization surgery in adult patients with ischemic moyamoya disease

Introduction: Revascularization surgery for adult moyamoya disease (MMD) with ischemic presentation changes cognitive function and prevents further cerebral ischemic events. Most studies, however, repeated neuropsychological evaluation within 1 year after surgery. Our previous prospective cohort study of adult patients with MMD with misery perfusion who underwent direct revascularization surgery showed cognitive improvement and decline in 31% and 44%, respectively, of the patients 2 months after surgery. The present prospective study aimed to elucidate the 5-year cognitive changes after direct revascularization surgery in adult patients with cerebral misery perfusion due to ischemic MMD by following the same patients. Methods: In total, 31 patients were prospectively followed up for 5 years after direct revascularization surgery. Five types of neuropsychological tests were performed preoperatively, 2 months after surgery, and at the end of the 5-year follow-up. Cerebral blood flow in the symptomatic cerebral hemisphere relative to that in the ipsilateral cerebellar hemisphere (hemispheric RCBF) was measured using brain perfusion single-photon emission computed tomography preoperatively and at the end of the 5-year follow-up. Results: Based on results of pre- and postoperative neuropsychological tests, 11, 10, and 10 patients showed cognitive improvement, no change in cognitive function, and cognitive decline, respectively, at the end of the 5-year follow-up. These ratios were not significantly different compared with those 2 months after surgery (cognitive improvement, no change in cognitive function, and cognitive decline in 10, eight, and 13 patients, respectively). Although hemispheric RCBF was significantly greater at the end of the 5-year follow-up than before surgery in patients with cognitive improvement (80.7 ± 6.1% versus 92.9 ± 5.5%; p = 0.0033) and in those showing no change in cognitive function (85.6 ± 3.5 versus 91.5 ± 5.2%; p = 0.0093), this value was significantly lower at the end of the 5-year follow-up than before surgery in patients with cognitive decline (83.8 ± 3.7 versus 81.0 ± 5.8%; p = 0.0367). Conclusion: One-third of adult patients with cerebral misery perfusion due to ischemic MMD who underwent direct revascularization surgery exhibited cognitive improvement, and one-third exhibited decline at the end of the 5-year follow-up. The former and latter patients had increased and decreased CBF, respectively, in the affected cerebral hemisphere at the end of the 5-year follow-up compared with preoperative brain perfusion.

Five-Year Outcomes of Medical Management Alone for Adult Patients with Ischemic Moyamoya Disease without Cerebral Misery Perfusion

<b><i>Introduction:</i></b> No clear guidelines for treating adult patients with ischemic moyamoya disease (MMD) without cerebral hemodynamic compromise such as misery perfusion have been established. Our previous prospective cohort study of adult patients with MMD without misery perfusion who were treated with medical management alone, including an antiplatelet drug, showed a recurrent ischemic event rate of 3% per 2 years. The present prospective study aimed to elucidate the 5-year clinical, cerebral perfusion, and cognitive outcomes of medical management alone for Japanese adult patients with ischemic MMD without cerebral misery perfusion by following the same patients for another 3 years. <b><i>Methods:</i></b> In total, 68 patients without recurrent events at a 2-year follow-up were prospectively followed up for another 3 years. Cerebral blood flow (CBF) in the symptomatic cerebral hemisphere was measured using brain perfusion single-photon emission computed tomography at inclusion and at the end of the subsequent 3-year follow-up. Neuropsychological testing was performed at inclusion and at the end of the initial 2- and subsequent 3-year follow-ups. <b><i>Results:</i></b> During the subsequent 3-year follow-up, 2 patients (3%) developed further ischemic events. In patients without further ischemic events, CBF was significantly greater at the end of the subsequent 3-year follow-up than at inclusion (<i>p</i> = 0.0037), and all neuropsychological test scores improved or remained unchanged at the end of initial 2- and subsequent 3-year follow-ups compared with that at inclusion. <b><i>Conclusion:</i></b> In adult patients receiving medical management alone for ischemic MMD without cerebral misery perfusion, the incidence of further ischemic events was 6% per 5 years and did not change between the initial 2 years after the last is­chemic event and the subsequent 3 years. In patients without further ischemic events, CBF and cognitive function had not deteriorated at 5 years after the last ischemic event.

Impact of cerebral blood flow changes due to arterial bypass surgery on cognitive function in adult patients with symptomatic ischemic moyamoya disease

OBJECTIVESome adult patients with moyamoya disease (MMD) undergoing revascularization surgery show an improvement or decline in cognition postoperatively. Revascularization surgery for ischemic MMD augments cerebral blood flow (CBF) and improves cerebral oxygen metabolism. However, cerebral hyperperfusion, which is a short-term, major increase in ipsilateral CBF that is much greater than the metabolic needs of the brain, sometimes occurs as a complication. Cerebral hyperperfusion produces widespread, minimal injury to the ipsilateral white matter and cortical regions. The aim of the present prospective study was to determine how changes in CBF due to arterial bypass surgery affect cognitive function in adult patients with symptomatic ischemic MMD and misery perfusion.METHODSThirty-two patients with cerebral misery perfusion, as determined on the basis of 15O gas positron emission tomography, underwent single superficial temporal artery–middle cerebral artery (M4 in the precentral region) anastomosis. Brain perfusion single-photon emission computed tomography (SPECT) studies were performed preoperatively, on the 1st postoperative day, and 2 months after surgery. Neuropsychological tests were also performed preoperatively and 2 months after surgery.RESULTSPostoperative neuropsychological assessments demonstrated cognitive improvement in 10 cases (31%), no change in 8 cases (25%), and decline in 14 cases (44%). Based on brain perfusion SPECT and symptoms, 10 patients were considered to have cerebral hyperperfusion syndrome, and all of these patients exhibited a postoperative decline in cognition. Relative precentral CBF on the 1st postoperative day was significantly greater in patients with postoperative cognitive decline (167.3% ± 15.3%) than in those with improved (105.3% ± 18.2%; p < 0.0001) or unchanged (131.4% ± 32.1%; p = 0.0029) cognition. The difference between relative precentral CBF 2 months after surgery and that before surgery was significantly greater in patients with postoperative cognitive improvement (17.2% ± 3.8%) than in those with no postoperative change (10.1% ± 2.4%; p = 0.0003) or with postoperative decline (11.5% ± 3.2%; p = 0.0009) in cognition.CONCLUSIONSCerebral hyperperfusion in the acute stage after arterial bypass surgery impairs cognitive function. An increase in CBF in the chronic stage without acute-stage cerebral hyperperfusion improves cognitive function in adult patients with symptomatic ischemic MMD and misery perfusion.

Preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease

The present study examined whether preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with development of cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease. Among 65 adult patients with ischemic moyamoya disease, 19 had misery perfusion in the precentral region on preoperative 15O positron emission tomography and underwent arterial bypass surgery for that region. Brain technetium-99 m-labeled ethyl cysteinate dimer single-photon emission computed tomography (SPECT) was preoperatively performed with and without hyperventilation challenge and relative cerebrovascular contractile reactivity to hypocapnia (RCVCRhypocap) (%/mmHg) was calculated in the precentral region. Development of cerebral hyperperfusion syndrome was determined using perioperative changes of symptoms and brain N-isopropyl-p-[123I]-iodoamphetamine SPECT performed after surgery. RCVCRhypocap was significantly lower in the 6 patients with cerebral hyperperfusion syndrome (−2.85 ± 1.10%/mmHg) than in the 13 patients without cerebral hyperperfusion syndrome (0.18 ± 1.97%/mmHg; p = 0.0050). Multivariate analysis demonstrated low RCVCRhypocap as an independent predictor of cerebral hyperperfusion syndrome (95% confidence interval, 0.04–0.96; p = 0.0433). Preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with development of cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease.