Transient Global Cerebral Hypoperfusion as a Characteristic Cerebral Hemodynamic Pattern in the Acute Stage after Combined Revascularization Surgery for Pediatric Moyamoya Disease: N-Isopropyl-P-[123I] Iodoamphetamine Single-Photon Emission Computed Tomography Study

<b><i>Introduction:</i></b> Surgical revascularization prevents cerebral ischemic attack by improving cerebral blood flow (CBF) in both adult and pediatric patients with moyamoya disease (MMD). Uneven hemodynamic changes, including local cerebral hyperperfusion and remote ischemia, can cause delayed intracerebral hemorrhage and perioperative infarctions in adult MMD patients, but the characteristic hemodynamic pattern among pediatric MMD patients after revascularization surgery is poorly understood. <b><i>Methods:</i></b> This study included 16 consecutive pediatric MMD patients (age, 6–16 years; mean age, 11.3) undergoing superficial temporal artery-middle cerebral artery anastomosis combined with encephalo-duro-myo-synangiosis on 21 affected hemispheres. Perioperative management was conducted by aspirin administration and strict blood pressure control (110–130 mm Hg). We prospectively performed N-isopropyl-p-[¹²³I] iodoamphetamine single-photon emission computed tomography on postoperative days (POD) 1 and 7 and analyzed the temporal changes in perioperative hemodynamics. <b><i>Results:</i></b> Four patients (19.0%, 4/21) exhibited immediate CBF improvement from POD 1, which was classified as “immediate redistribution pattern.” In contrast, 9 (42.9%, 9/21) demonstrated transient hemispheric global hypoperfusion at POD 1 and subsequent CBF improvement at POD 7, which was defined as “transient hypoperfusion pattern.” Although 8 patients, including 4 with “transient hypoperfusion pattern” (44.4, 4/9), developed mild transient neurological deterioration in the acute stage, it resolved in all 21 patients, and there were no permanent neurological deficits. <b><i>Discussion/Conclusions:</i></b> This study revealed that the “transient hypoperfusion pattern” after revascularization surgery is relatively common among pediatric MMD patients, and its outcome is favorable under strict perioperative management.

Two Sides of a Coin: Case Report of Unilateral Synangiosis and Contralateral Stroke Highlighting Consequences of Disease Progression and Efficacy of Revascularization in Sickle Cell Disease Associated Moyamoya Syndrome

Moyamoya syndrome increases the risk of stroke in sickle cell disease, but revascularization surgery can modify this risk. Collaborative management between hematology and neurosurgery offers effective strategies to reduce stroke risk in these patients. We describe a challenging case where a patient with sickle cell disease undergoing standard of care management as prescribed by the Stroke Prevention Trial in Sickle Cell Anemia (STOP) and revascularization with pial synangiosis subsequently developed rapidly progressive disease in other cerebral vessels and suffered ischemic hemispheric stroke. This case demonstrates the success of management in accordance with American Heart Association (AHA) and American Stroke Association (ASA) guidelines, but also demonstrates critical areas where we lack understanding of disease progression.

Acetazolamide-Challenged Arterial Spin Labeling Detects Augmented Cerebrovascular Reserve After Surgery for Moyamoya

Background and Purpose: Cerebrovascular reserve (CVR) inversely correlates with stroke risk in children with Moyamoya disease and may be improved by revascularization surgery. We hypothesized that acetazolamide-challenged arterial spin labeling MR perfusion quantifies augmentation of CVR achieved by revascularization and correlates with currently accepted angiographic scoring criteria. Methods: We retrospectively identified pediatric patients with Moyamoya disease or syndrome who received cerebral revascularization at ≤18 years of age between 2012 and 2019 at our institution. Using acetazolamide-challenged arterial spin labeling, we compared postoperative CVR to corresponding preoperative values and to postoperative perfusion outcomes classified by Matsushima grading. Results: In this cohort, 32 patients (17 males) with Moyamoya underwent 29 direct and 16 indirect extracranial-intracranial bypasses at a median 9.7 years of age (interquartile range, 7.6–15.7). Following revascularization, median CVR increased within the ipsilateral middle cerebral artery territory (6.9 mL/100 g per minute preoperatively versus 16.5 mL/100 g per minute postoperatively, P <0.01). No differences were observed in the ipsilateral anterior cerebral artery ( P =0.13) and posterior cerebral artery ( P =0.48) territories. Postoperative CVR was higher in the ipsilateral middle cerebral artery territories of patients who achieved Matsushima grade A perfusion, in comparison to those with grades B or C (25.8 versus 17.5 mL, P =0.02). The method of bypass (direct or indirect) did not alter relative increases in CVR (8 versus 3.8 mL/100 g per minute, P =0.7). Conclusions: Acetazolamide-challenged arterial spin labeling noninvasively quantifies augmentation of CVR following surgery for Moyamoya disease and syndrome.

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.

Anesthetic Management of Moyamoya Syndrome Secondary to Sickle Cell Anemia

Moyamoya disease (MMD) is caused by stenosis or occlusion of internal carotid artery in brain, thereby reducing its blood supply. To augment blood flow, brain develops abnormal anastomotic vessels with deranged carbon dioxide reactivity and tendency to bleed. Moyamoya syndrome (MMS) is the name given to MMD when the latter results from secondary to some associated disease. Occurrence of MMS secondary to sickle cell anemia (SCA) presents unique challenges to neuroanesthesiologists. Management of various physiological parameters for cerebral revascularization surgery for MMD under general anesthesia necessitates vigilant and balanced control of various physiological variables, as the manipulation of a particular physiological variable for one pathology may adversely impact the same physiological variable for the associated disease, which will result in poor outcome of the patient. Therefore, optimum outcome of MMS is determined by a watchful balancing of various physiological parameters under anesthesia.

The First 24 h Hemodynamic Management in NICU after Revascularization Surgery in Moyamoya Disease

Objective. To evaluate whether hemodynamic factors are risk factors for prognosis in moyamoya disease (MMD). Materials and Methods. The retrospective study reviewed a single-center MMD cohort in Huashan Hospital from August 2017 to January 2020. Stroke events in 30 days and follow-up modified Rankin Scale (mRS) grade were recorded. Systematic assessments with perioperative mean arterial pressure (MAP), red blood cell (RBC) parameters, and fluid management were also conducted. Logistic regressions were applied to evaluate the predictors of worse outcomes. Data was analyzed using SPSS 24.0. Results. Admission to neurological intensive care unit (NICU) totalled about 347 after revascularization surgery. The result showed that the higher the postoperative MAP level (favorable group 95.7 ± 11.4 mmHg vs. unfavorable group 103.6 ± 10.4 mmHg, p < 0.001 ) and the greater the MAP variability (favorable group 0.26 ± 13.2 vs. unfavorable group 7.2 ± 13.5 , p = 0.006 ) were, the higher the patient’s follow-up mRS grade was. What is more, a higher early postoperative Hb level also seemed to predict a worse long-term clinical outcome (favorable group 116.9 ± 17.1 g/L vs. unfavorable group 123.7 ± 13.0 g/L, p = 0.03 ), but the difference disappeared after adjusting sex and age. Logistic regression analyses showed that a higher level of postoperative MAP ( β = 0.024 , 95% CI (0.004, 0.044), and p = 0.02 ) within the first 24 h in NICU might be the short-term risk factor. For long-term outcome, a higher level ( β = 1.058 , 95% CI (1.022, 1.096), and p = 0.001 ) and a greater variability ( β = 30.982 , 95% CI (2.112, 454.414), and p = 0.01 ) of postoperative MAP might be the negative predictors of mRS grade. Conclusions. The early postoperative hemodynamic management might be extremely critical for patients with MMD. Both high postoperative MAP levels and large MAP variability might affect the prognosis. What is more, we also found that a higher postoperative Hb level might be related with a worse outcome.

Benefits and risks of antiplatelet medication in hemodynamically stable adult moyamoya disease

Revascularization surgery is considered a standard treatment for preventing additional stroke in symptomatic moyamoya disease (MMD). In hemodynamically stable, and asymptomatic or mildly symptomatic patients, however, the treatment strategy is controversial because of the obscure natural course of them. The authors analyzed the benefits and risks of antiplatelet medication in those patients. Medical data were retrospectively reviewed in 439 hemispheres of 243 patients with stable hemodynamic status. Overall, 121 patients (49.8%) with 222 studied hemispheres (50.6%) took antiplatelet medication. Symptomatic cerebral infarction and hemorrhage occurred in 10 (2.3%) and 30 (6.8%) hemispheres, over a mean follow-up of 62.0 ± 43.4 months (range 6–218 months). The use of antiplatelet agents was statistically insignificant in terms of symptomatic infarction, hemorrhage and improvement of ischemic symptoms. In subgroup analyses within the antiplatelet group according to drug potency and duration of medication, a longer duration of antiplatelet medication significantly improved ischemic symptoms (adjusted OR 1.02; 95% CI 1.01–1.03; p = 0.006). Antiplatelet medication failed to prevent symptomatic cerebral infarction or improve ischemic symptoms. However, antiplatelet therapy did not increase the risk of cerebral hemorrhage.

Vascular Diameters as Predictive Factors of Recanalization Surgery Outcomes in Internal Carotid Artery Occlusion

Background: Revascularization surgery sometimes can achieve recanalization in patients with internal carotid artery occlusion (ICAO). High-resolution vessel wall magnetic resonance imaging (HRVWI) is a feasible technique to give detailed characteristics of the vessel wall, which may help to identify patients that carry higher success rates and more suitable for revascularization surgery.Objective: To examine the association between HRVWI characteristics of ICAO and the success rate of revascularization surgery in ICAO patients.Methods: We conducted a retrospective analysis of 31 ICAO recanalization patients enrolled from October 2017 to May 2019. The clinical data of patients and lesions were collected and analyzed.Results: A total of 31 ICAO patients were enrolled in this study. No significant differences were found between recanalization success and recanalization failure groups with regard to occlusion length, distal end of the occluded segment, and the treatment applied. The ipsilateral-to-contralateral diameter ratios (I/C ratios) of C1 or C2 and the diameter of C7 were positively related to recanalization success. A two-factor predictive model was constructed, and the I/C ratio of C2 &lt; 0.86 and the diameter of C7 &lt; 1.75mm were separately assigned 1 point. The ICAO patients who scored 0, 1, or 2 points had a risk of 5.6% (1/18), 55.6% (5/9), or 100% (4/4) to fail in the recanalization.Conclusions: The I/C ratios of C1 or C2 and the diameter of C7 are predictive factors of a revascularization surgery success in ICAO patients. A risk stratification model involving C2 and C7 was constructed for future clinical applications.