Direct Bypass Surgery Research Articles

Association of Retrograde Bypass Flow Depth Along Cortical Recipient Arteries with Revascularization Outcomes in Direct Bypass Surgery for Moyamoya Disease

Association of Retrograde Bypass Flow Depth Along Cortical Recipient Arteries with Revascularization Outcomes in Direct Bypass Surgery for Moyamoya Disease

3D exoscopic versus microscopic superficial temporal artery to middle cerebral artery bypass surgery for moyamoya disease – a comparative series

PurposeSuperficial temporal artery to middle cerebral artery (STA-MCA) direct bypass surgery is the most common surgical procedure to treat moyamoya disease (MMD). Here, we aim to compare the performance of the 3D exoscope in bypass surgery with the gold standard operative microscope.MethodsAll direct STA-MCA bypass procedures performed at a single university hospital for MMD between 2015 and 2023 were considered for inclusion. Data were retrospectively collected from patient files and surgical video material. From 2020 onwards, bypass procedures were exclusively performed using a digital three-dimensional exoscope as visualization device. Results were compared with a microsurgical bypass control group (2015–2019). The primary endpoint was defined as total duration of surgery, duration of completing the vascular anastomosis (ischemia time), bypass patency, number of stiches to perform the anastomosis, added stiches after leakage testing of the anastomosis and the Glasgow outcome scale (GOS) at last follow-up as secondary outcome parameter.ResultsA total of 16 consecutive moyamoya patients underwent 21 STA-MCA bypass procedures. Thereof, six patients were operated using a microscope and ten patients using an exoscope (ORBEYE® n = 1; AEOS® n = 9).Total duration of surgery was comparable between devices (microscope: 313 min. ± 116 vs. exoscope: 279 min. ± 42; p = 0.647). Ischemia time also proved similar between groups (microscope: 43 min. ± 19 vs. exoscope: 41 min. ± 7; p = 0.701). No differences were noted in bypass patency rates. The number of stiches per anastomosis was similar between visualization devices (microscope: 17 ± 4 vs. exoscope: 17 ± 2; p = 0.887). In contrast, more additional stiches were needed in microscopic anastomoses after leakage testing the bypass (p = 0.035).ConclusionTaking into account the small sample size, end-to-side bypass surgery for moyamoya disease using a foot switch-operated 3D exoscope was not associated with more complications and led to comparable clinical and radiological results as microscopic bypass surgery.

Reversible sulcal fluid-attenuated inversion recovery hyperintensity after combined bypass surgery for moyamoya disease - A "crevasse" sign.

Transient fluid-attenuated inversion recovery (FLAIR) hyperintensity is often observed on the operated brain surface after direct or combined bypass surgery for moyamoya disease, but its pathophysiology and clinical significance are still obscure. This study was aimed to clarify the underlying mechanism and clinical significance. This prospective study included 106 hemispheres of 61 patients with moyamoya disease and analyzed their radiological findings before and after combined bypass surgery. This study also included 11 patients who underwent superficial temporal artery to middle cerebral artery anastomosis for occlusive carotid artery diseases as the controls. Magnetic resonance imaging examination was serially repeated, and cerebral blood flow was measured before and after surgery. Signal intensity ratio (SIR) in the cortical sulci and cortex to the adjacent white matter on FLAIR images was calculated, and the postoperative SIR changes were semi-quantitatively evaluated to assess the temporal profile of postoperative FLAIR hyperintensity. Postoperative FLAIR hyperintensity occurred within the cortical sulci on the operated hemispheres in all moyamoya patients but not in patients with occlusive carotid artery diseases. SIR values started to increase immediately after surgery, peaked at about 4-fold at 4-13 days post-surgery, then declined, and recovered to baseline values over 28 days or later. The magnitude of this phenomenon was proportional to the severity of cerebral ischemia but not to postoperative hyperperfusion. Reversible sulcal FLAIR hyperintensity specifically occurs in the operated hemispheres after direct bypass surgery for moyamoya disease. This "crevasse sign" may represent the mixture of the extensive leakage of oxygen and proteins from the pial arteries into the CSF.

Inhalational Anesthesia Reduced Transient Neurological Events After Revascularization Surgery for Moyamoya Disease

BACKGROUND AND OBJECTIVES: The choice between inhalational and total intravenous anesthesia (TIVA) in revascularization surgery for Moyamoya disease (MMD) remains a topic of debate. Anesthesia methods have changed with the advent of new anesthetics. This study investigated whether modern anesthesia methods affected the development of neurological symptoms after revascularization surgery for MMD. METHODS: This single-center retrospective study included 63 adult patients (82 hemispheres) with MMD treated with direct and indirect bypass surgeries at our hospital between 2013 and 2022. Patients were divided into inhalational anesthesia (IA) and TIVA groups based on the anesthesia maintenance method. Baseline patient characteristics; postoperative neurological symptoms, including hyperperfusion syndrome, cerebral infarction, and transient neurological events (TNEs); and cortical hyperintensity belt (CHB) sign scores (5-point scale from 0 to 4) on postoperative magnetic resonance imaging were compared between the two groups. The operation methods, anesthetics, and intraoperative hemodynamic and ventilatory parameters were compared between patients with and without TNEs. RESULTS: The IA and TIVA groups comprised 39 and 43 hemispheres, respectively. The frequency of postoperative hyperperfusion syndrome and cerebral infarction did not differ between the groups, but the number of TNEs in the IA group (5/39; 13%) was significantly lower than that in the TIVA group (16/43; 37%). Multivariate logistic regression analysis revealed that TNEs were associated with TIVA (odds ratio, 3.91; 95% CI, 1.24-12.35; P = .02). The median [IQR] postoperative CHB sign score in the IA group (2 [1-3]) was significantly lower than that in the TIVA group (4 [3-4]). CONCLUSION: The IA group had fewer postoperative TNEs and lower CHB sign scores than the TIVA group. Although further studies are needed, this study provides insights into the prevention of TNEs with IA and reconsideration of the optimal anesthesia for MMD.

Combination of intraoperative indocyanine green video-angiography FLOW 800 and computed tomography perfusion to assess the risk of cerebral hyperperfusion syndrome in chronic internal carotid artery occlusion patients after revascularization surgery.

To study the changes of corticocerebral hemodynamics in surgical area and postoperative hyperperfusion syndrome in patients with chronic internal carotid artery occlusion (CICAO) by intraoperative indocyanine green videoangiography (ICGA)-FLOW 800 and CT perfusion after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery. From October 2019 to January 2021, 77 patients diagnosed with CICAO underwent direct bypass surgery at Huadong hospital (affiliated with Fudan University) were enrolled. Regions of interest (ROIs) at STA, proximal MCA (PMCA), distal MCA (DMCA), cortical blood capillary (CBC), and cortical vein (CV) were identified after anastomosis by ICGV-FLOW 800 including peak fluorescence intensity (PFI), time to peak (TTP), and area under the time curve (AUC) of fluorescence intensity. All patients underwent perfusion-weighted CT before bypass surgery and those patients with HPS were verified by CTP after bypass. 14 patients with HPS were verified by perfusion-weighted CT after bypass. In HPS group, the AUCTTP of DMCA was significantly larger (T = -3.301, p = 0.004) and TTP of CBC was shorter (T = -2.929, p = 0.005) than patients in non-HPS group. The larger AUCTTP of DMCA (OR = 3.024, 95%CI 1.390-6.578, p = 0.0050) was an independent risk factor by further multivariate logistic regression analysis. The hemodynamic changes of cortical vessels during STA-MCA bypass surgery could be recorded accurately by ICGV-FLOW 800. Furthermore, the increased AUCTTP of DMCA and shorter TTP of CBC may be potential risk factors of HPS.

Arterialized Vein Immediately After Direct Bypass Surgery Indicates Cerebral Hyperperfusion Syndrome in Moyamoya Disease.

Arterialized Vein Immediately After Direct Bypass Surgery Indicates Cerebral Hyperperfusion Syndrome in Moyamoya Disease.

Aneurysm appearing at the anastomosis site 11 years after superficial temporal artery–middle cerebral artery bypass surgery: moyamoya disease with a rapidly growing aneurysm. Illustrative case

BACKGROUND Superficial temporal artery–middle cerebral artery (STA-MCA) bypass surgery is performed to prevent ischemia and hemorrhage in patients with moyamoya disease. Only a few reports have described aneurysms appearing around the anastomosis site after bypass surgery, and the underlying mechanism remains unknown. OBSERVATIONS The present case involved a 62-year-old woman who underwent STA-MCA bypass surgery for ischemic quasi-moyamoya disease at 46 years of age. Postoperatively, she underwent annual magnetic resonance imaging examinations. At 11 years after STA-MCA bypass surgery, a 3-mm aneurysm appeared at the anastomosis site. Four years later, headache developed and the aneurysm had grown to 5 mm. Craniotomy clipping was performed to prevent rupture. The patient was discharged home 2 weeks after surgery without any apparent complications. LESSONS Long-term observation is crucial after direct bypass surgery for moyamoya disease. Measures to prevent rupture should be considered for cases involving aneurysm complications.

Recurrent Stroke in Young Adult as a Manifestation of Moyamoya Disease: Case Report

Background: Moyamoya disease is a chronic cerebrovascular disorder characterized by progressive narrowing of the intracranial portions of the distal internal carotid artery, the initial proximal components of the middle cerebral artery, anterior cerebral artery, and posterior cerebral artery. Moyamoya disease can manifest as a stroke in young adult. Methods: This report presents a young female patient with Moyamoya disease in Siloam Hospital Denpasar, Bali, Indonesia, diagnosed using MRI and Digital Subtraction Angiography. Case Report: A 29-year-old woman with recurrent stroke, presented with right-side hemiparesis, urinary incontinence, disinhibition syndrome, hypertension, and a history of left hemiparesis from a previous stroke. The MRI brain showed hyperintensity throughout the sulci (ivy sign) in the bilateral frontoparietal with acute infarct in the left frontomedial region, chronic infarct in right frontomedial, occlusion of bilateral carotid arteries (supraclinoid segment), bilateral MCA and ACA. The cerebral DSA study showed stenosis in the right ICA, stenosis in the M1-M2 junction with poor collateral to ACA territory with a puff of smoke appearance, occlusion in the left ICA (supraclinoid segment), and severe stenosis in M1. The patient had undergone direct bypass in the right MCA and right superficial temporal artery. Unfortunately, the bypass did not succeed because of infection of the bypass site and the patient got oral medication with a single antiplatelet (asetosal) and angiotensin receptor blocker (valsartan). Discussion: Moyamoya disease is a rare chronic cerebrovascular disorder that can manifest as an ischaemic stroke in young adult. This patient had a recurrent ischaemic stroke due to Moyamoya disease. According to a global multicenter stroke database, 90% of Moyamoya disease patients initially presented with an ischemic stroke, 7.5% with a transient ischemic attack, and 2.5% with a hemorrhagic stroke. DSA showed that the intracranial collateral system failed to fulfill the demand for brain circulation when the stroke occurred. The patient had failure to grow collateral after direct bypass surgery from the right superficial temporal artery to MCA and single oral antiplatelet as a secondary prevention for ischaemic stroke. Conclusion: Moyamoya disease is a rare disease that needs further studies for its treatment to halt the progression and prevent secondary complications. Young patients with ischaemic stroke needed to be asses with brain MRI, MRA, and DSA to evaluate the etiology of ischaemic stroke. Keywords: Moyamoya disease, Digital Substraction Angiography,ischaemic stroke

Flow volume mismatch dramatically affects transient neurologic symptoms after direct bypass in Moyamoya disease.

Transient neurological events (TNEs) occur after bypass surgery in Moyamoya disease (MMD); however, their pathology remains unknown. To elucidate the pathophysiology of TNEs, we investigated their relationship with perioperative superficial temporal artery (STA) blood flow volume, which was evaluated using ultrasonography. Forty-nine patients with MMD, who underwent direct bypass surgery, were included and stratified into TNE and non-TNE groups, respectively. The STA blood flow volume was evaluated at four time points (preoperatively and 2-4, 7, and 10-14days postoperatively), and a change in volume during the postoperative period was defined as a flow volume mismatch. We investigated the association between ultrasonographic findings of flow volume mismatch and TNEs and magnetic resonance imaging findings, such as the cortical hyperintensity belt (CHB) sign, using univariate and path analyses. The STA blood flow volume increased immediately postoperatively, gradually decreasing over time, in both groups. The TNE group showed a significant increase in blood flow volume 2-4days postoperatively (P = 0.042). Flow volume mismatch was significantly larger in the TNE group than in the non-TNE group (P = 0.020). In the path analysis, STA flow volume mismatch showed a positive association with the CHB sign (P = 0.023) and TNEs (P = 0.000). Additionally, the CHB sign partially mediated the association between STA flow volume mismatch and TNEs. These results suggest that significantly high STA blood flow volume changes occurring during the acute postoperative period after direct bypass surgery in MMD are correlated with TNEs and the CHB sign, suggesting involvement in the pathophysiology of TNEs.

Reconstruction of Scalp Defects Using Rotational Flaps After Revascularization Surgery in Patients with Moyamoya Disease

Treating scalp defects after revascularization surgery is difficult because the scalp microcirculation is severely compromised. We aimed to review the clinical effects of using rotational flaps in scalp defect reconstruction and explore risk factors for wound-related complications (WRC) after reconstruction surgery. We retrospectively identified patients with scalp defects after combined revascularization surgery who were surgically treated with rotational flap reconstruction at our institution between January 2018 and December 2022. We analyzed treatment results in different surgical technique and revascularization strategy cohorts, including direct bypass superficial temporal artery branch selection, indirect bypass types, and skin incisions. Eleven patients were included. The superficial temporal artery parietal branch was selected for direct bypass surgery in 10 (90.9%) patients, 4 (40%) of whom had WRC after flap reconstruction. Five types of indirect bypass surgeries were performed; three patients treated by encephalo-duro-myo-arterio-perio-synangiosis and 1 patient treated by encephalo-duro-myo-perio-synangiosis had WRC after flap reconstruction. Question mark (n= 6, 54.5%), curved (n= 4, 36.65%), and Y-shaped (n= 1, 9.1%) incisions were used; in the first three incision cohorts, 2 patients in each cohort had WRC after flap reconstruction. Patients had the following commonalities that may be risk factors for WRC after flap reconstruction: 1) wounds with nonviable bone exposure after revascularization surgery; 2) three or more tissues used as donor tissues and donor tissues containing the periosteum; and 3) thin scalp around the defect.

Pulsatility index of superficial temporal artery was associated with cerebral infarction after direct bypass surgery for moyamoya disease

ObjectiveDirect bypass surgery by superficial temporal artery (STA) – middle cerebral artery anastomosis is an established procedure for moyamoya disease (MMD). However, some patients may develop cerebral infarction (CI) due to the watershed shift phenomenon after the surgery. This study sought to investigate the correlation between the postoperative changes of STA flow as well as cerebral blood flow (CBF) and the incidence of CI after direct bypass surgery for MMD. MethodsWe conducted a retrospective study of 62 hemispheres in 50 subjects who underwent direct bypass surgery for MMD. All subjects underwent pre- and post-operative MR imaging, ultrasound evaluation of STA, and single-photon emission computed tomography. The presence of CI was correlated with preoperative CBF, the delta difference of each value of the STA between before and after the surgery, and the postoperative increase ratio of CBF. ResultsAll bypass procedures were patent, and CI was observed in 4 cases (6.4%). There was no significant association between the incidence of CI and both pre- and post-operative CBF. However, there was a significant difference in delta pulsatility index (PI) of the STA between cases with or without CI (-0.38±0.22 and -0.87±0.63, respectively, p=0.03). Whereas, other factors did not show any significant differences between those with or without CI. ConclusionsA relatively high postoperative PI of the STA was significantly associated with the incidence of CI after direct bypass surgery for MMD. A larger study is needed to confirm these findings.

Superior Visualization of Neovascularization with Silent Magnetic Resonance Angiography Compared to Time-of-Flight Magnetic Resonance Angiography After Bypass Surgery in Moyamoya Disease

The evaluation of postsurgical neoangiogenesis in patients with moyamoya disease (MMD) is crucial for appropriate patient management. This study aimed to assess the visualization of neovascularization after bypass surgery using noncontrast-enhanced silent magnetic resonance angiography (MRA) with ultrashort echo time and arterial spin labeling. After bypass surgery, 13 patients with MMD were followed up for >6months between September 2019 and November 2022. They underwent silent MRA in the same session as time-of-flight magnetic resonance angiography (TOF-MRA) and digital subtraction angiography (DSA). Two observers independently rated the visualization of neovascularization in both types of MRA from 1 (not visible) to 4 (nearly equal to DSA), with reference to DSA images as the standard. The mean scores were significantly higher for silent MRA compared with TOF-MRA (3.81±0.48 and 1.92±0.70, respectively) (P<0.01). The intermodality agreements were 0.83 and 0.71 for silent MRA and TOF-MRA, respectively. TOF-MRA depicted the donor artery and recipient cortical artery after direct bypass surgery, although fine neovascularization developed after indirect bypass surgery was poorly visualized. Silent MRA could reveal the developed bypass flow signal and perfused middle cerebral artery territory, which was almost equal to the DSA images. Silent MRA achieves better visualization of postsurgical revascularization in patients with MMD than TOF-MRA. Moreover, it may have the potential to provide visualization of the developed bypass flow equivalent to DSA.

Prediction of hemorrhagic cerebral hyperperfusion syndrome after direct bypass surgery in adult nonhemorrhagic moyamoya disease: combining quantitative parameters on RAPID perfusion CT with clinically related factors.

The aim of this study was to identify predictive factors for hemorrhagic cerebral hyperperfusion syndrome (hCHS) after direct bypass surgery in adult nonhemorrhagic moyamoya disease (non-hMMD) using quantitative parameters on rapid processing of perfusion and diffusion (RAPID) perfusion CT software. A total of 277 hemispheres in 223 patients with non-hMMD who underwent combined bypass were retrospectively reviewed. Preoperative volumes of time to maximum (Tmax) > 4 seconds and > 6 seconds were obtained from RAPID analysis of perfusion CT. These quantitative parameters, along with other clinical and angiographic factors, were statistically analyzed to determine the significant predictors for hCHS after bypass surgery. Intra- or postoperative hCHS occurred in 13 hemispheres (4.7%). In 7 hemispheres, subarachnoid hemorrhage occurred intraoperatively, and in 6 hemispheres, intracerebral hemorrhage was detected postoperatively. All hCHS occurred within the 4 days after bypass. Advanced age (OR 1.096, 95% CI 1.039-1.163, p = 0.001) and a large volume of Tmax > 6 seconds (OR 1.011, 95% CI 1.004-1.018, p = 0.002) were statistically significant factors in predicting the risk of hCHS after surgery. The cutoff values of patient age and volume of Tmax > 6 seconds were 43.5 years old (area under the curve [AUC] 0.761) and 80.5 ml (AUC 0.762), respectively. In adult patients with non-hMMD older than 43.5 years or with a large volume of Tmax > 6 seconds over 80.5 ml, more prudence is required in the decision to undergo bypass surgery and in postoperative management.

European Stroke Organisation (ESO) Guidelines on Moyamoya angiopathy Endorsed by Vascular European Reference Network (VASCERN).

The European Stroke Organisation (ESO) guidelines on Moyamoya Angiopathy (MMA), developed according to ESO standard operating procedure and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, were compiled to assist clinicians in managing patients with MMA in their decision making. A working group involving neurologists, neurosurgeons, a geneticist and methodologists identified nine relevant clinical questions, performed systematic literature reviews and, whenever possible, meta-analyses. Quality assessment of the available evidence was made with specific recommendations. In the absence of sufficient evidence to provide recommendations, Expert Consensus Statements were formulated. Based on low quality evidence from one RCT, we recommend direct bypass surgery in adult patients with haemorrhagic presentation. For ischaemic adult patients and children, we suggest revascularization surgery using direct or combined technique rather than indirect, in the presence of haemodynamic impairment and with an interval of 6-12 weeks between the last cerebrovascular event and surgery. In the absence of robust trial, an Expert Consensus was reached recommending long-term antiplatelet therapy in non-haemorrhagic MMA, as it may reduce risk of embolic stroke. We also agreed on the utility of performing pre- and post- operative haemodynamic and posterior cerebral artery assessment. There were insufficient data to recommend systematic variant screening of RNF213 p.R4810K. Additionally, we suggest that long-term MMA neuroimaging follow up may guide therapeutic decision making by assessing the disease progression. We believe that this guideline, which is the first comprehensive European guideline on MMA management using GRADE methods will assist clinicians to choose the most effective management strategy for MMA.

Filamentous Bacteria Resembling Fungal Hyphae: A Diagnostic Pitfall

Abstract Introduction/Objective When exposed to antibiotics or a host immune response, Gram-negative bacilli grow with inhibited septation producing long continuous cells; a phenomenon known as filamentation. Methods/Case Report We present a case of a 68-year-old man with quadriplegia, which was caused by the right vertebral artery dissection and subarachnoid hemorrhage requiring an emergent posterior inferior cerebellar artery direct bypass surgery. Lung lower lobe infiltrates were noted 3 days after the surgery. A bronchial wash culture was negative for growth, and a sputum specimen grew Serratia marcescens. The patient was treated with piperacillin/tazobactam, vancomycin, cefepime, cefazolin. After the surgery, he suddenly developed severe cerebral vasospasm of the posterior circulation with cerebellar strokes requiring emergent posterior fossa decompression. He remained on ventricular drainage by external ventricular drainage. After two days, the patient's cerebrospinal fluid (CSF) was sent for evaluation, on which a high segmented neutrophil count of 35% and Gram-negative filamentous organisms with occasional swellings were noted. Multi-drug resistant Serratia marcescens was isolated from the CSF specimen four days later. Neurosurgical procedures were reported to be highly associated with S. marcescens meningitis. The filamentous organisms noted on Gram-stained direct smear most likely represented Gram-negative S. marcescens with filamentation due to administration of sub-inhibitory concentrations of antibiotics. Results (if a Case Study enter NA) NA. Conclusion Gram-negative bacilli can develop abnormal morphology including elongation, swelling, and filamentation due to stress or sub-inhibitory antibiotic exposure, and it is important for microbiologists and pathologists to be aware of this phenomenon to avoid misinterpretation that may lead to inappropriate treatment.

Direct Bypass Surgery for Moyamoya and Steno-occlusive Vasculopathy: Clinical Outcomes, Intraoperative Blood Flow Analysis, Long-term Follow-up, and Long-term Bypass Patency in a Single Surgeon Case Series of 162 Procedures

Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for the treatment of cerebral hypoperfusion secondary to chronic steno-occlusive vasculopathy. We sought to determine clinical outcomes, intraoperative blood flow analysis, long term follow up, and long term patency rates from a single surgeon's series of direct cerebral bypass for moyamoya disease, moyamoya syndrome, and steno-occlusive disease. We reviewed clinical, demographic, operative and neuroimaging records for all patients who underwent a direct EC-IC bypass by the senior author between August 1999 and November 2020. Primary outcomes analyzed were functional long-term outcomes (by modified Rankin score [mRS]), surgical complications, and short-term and long-term bypass patency. A total of 162 revascularization procedures in 124 patients were performed. Mean clinical follow up time was 2 years 11 months. The combined immediate and long term postoperative stroke and/or intracerebral hemorrhage rate was 6.2%. There were 17 bypasses (10%) that were found to be occluded at long-term follow-up, all but one were asymptomatic. Long-term graft occlusion was correlated with presence of complete collateralization on preoperative angiography but not cut flow index (CFI). Overall, patients had a significant clinical improvement with a mean mRS score 1.8 preoperatively and 1.2 postoperatively. In our consecutive series of patients treated with direct EC-IC cerebral bypass, there was significant improvement in functional outcome as measured by the mRS. The long term patency rate was 90%. There was a statistically significant correlation between complete or incomplete angiographic collateralization patterns and long-term bypass occlusion. There was no correlation between bypass type, clinical syndrome, or CFI and long-term occlusions. The role of bypass surgery and the need for surgical expertise remain strong in the treatment of moyamoya variants and a select group of atherosclerotic steno-occlusive patients.

Larger Posterior Revascularization Associated with Reduction of Choroidal Anastomosis in Moyamoya Disease: A Quantitative Angiographic Analysis.

Choroidal anastomosis, a hemorrhage-prone periventricular collateral manifestation in Moyamoya disease, outflows to the cortex posterior to the central sulcus. The objective of the present study was to test whether the angiographic extent of revascularization posterior to the central sulcus contributes to the postoperative reduction of choroidal anastomosis. This retrospective cohort study included choroidal anastomosis-positive hemispheres before direct bypass surgery. The postoperative reduction of choroidal anastomosis was determined by a consensus of 2 raters according to the previous research. An imaging software automatically traced the angiographic revascularization area, which was subsequently divided into anterior and posterior parts by an anatomic line corresponding to the central sulcus. Each area was quantitatively measured as a percentage relative to the whole supratentorial area. Postoperative reduction of choroidal anastomosis was achieved in 68 (85.0%) of the 80 included hemispheres. The revascularization area posterior to the central sulcus was significantly larger in the hemispheres with reduction than in those with no reduction (mean, 15.2% [SD, 7.1%] versus 4.2% [SD, 3.4%], P < .001), whereas no significant difference was observed in the revascularization area anterior to the central sulcus. Multivariate analysis revealed that the revascularization area posterior to the central sulcus was the only significant factor associated with reduction (OR, 1.57; 95% CI, 1.21-2.03, for every 1% increase). The results suggest that a larger revascularization posterior to the central sulcus is associated with postoperative reduction of choroidal anastomosis regardless of the extent of anterior revascularization. It might facilitate optimal selection of the revascularization site for preventing hemorrhage.

Extracranial-to-Intracranial Bypass for Distal Internal Carotid Artery and/or Proximal Middle Cerebral Artery Steno-Occlusive Disease: A Case Series of Clinical Outcomes at a Single, High-Volume Cerebrovascular Center.

Extracranial-to-intracranial (EC-IC) bypass was first described by Yasargil in the 1960s for treatment of symptomatic distal internal carotid artery (ICA) and/or proximal middle cerebral artery (MCA) steno-occlusive disease through direct anastomosis. Subsequent bypass trials failed to demonstrate benefit for overall outcomes and stroke rates compared with best medical therapy. However, the procedure remained in the neurosurgeon's armament, with studies showing benefits in select patient populations. With advancements in technology, patient selection has become more comprehensive. To provide a contemporary evaluation of EC-IC bypass from our high-volume cerebrovascular center, focusing on associated clinical outcomes. Consecutive patients who underwent direct EC-IC bypass surgeries for symptomatic distal ICA and/or proximal MCA steno-occlusive disease between April 2015 and September 2019 were identified retrospectively. Medical records were reviewed to collect demographics, clinical presentation, computed tomography perfusion imaging findings, transcranial Doppler results, procedure indication, donor vessel types, anastomosis site, bypass patency, periprocedural complications, postprocedural complications, symptom recrudescence, repeat or new interventions, subjective improvements, and modified Rankin Scale scores. We identified 27 patients who underwent 32 EC-IC bypass procedures. The rate of ipsilateral stroke was 9.4%, with a median follow-up of 8 months (IQR, 4-13 months). Patients experienced a 22.3% improvement in modified Rankin Scale scores, and 70.3% of patients reported subjective improvement and satisfaction at follow-up. Direct EC-IC bypass remains a viable option for revascularization in symptomatic patients with distal ICA and/or proximal MCA steno-occlusive disease.

Abstract TMP75: Vasomotor Reactivity As A Predictor Of Angiographic Collateralization And Outcome In Patients Undergoing Extracranial-Intracranial Bypass Surgery

Background: Extracranial-Intracranial (EC-IC) bypass is increasingly used for treatment of hemodynamic failure in Moya-Moya disease (MMD) or syndrome (MMS). No specific imaging parameter has been established to determine bypass patency in these patients. We sought to determine if vasomotor reactivity (VMR) testing could be correlated with pre-operative angiographic data and predict bypass patency. Methods: All available pre-operative VMRs and diagnostic angiograms (DSA) in patients with EC-IC direct bypass surgeries performed at our institution from 2007-2019 were reviewed to determine the degree of pre-procedural hemispheric failure (by VMR to the inhalation of carbon dioxide and hyperventilation, abnormal defined by less than 70%) and collateral compensation (categorized as complete vs. incomplete collaterals by DSA). Bypass patency was assessed on follow-up imaging (either immediate in post-op angiogram and delayed subsequent CTA or DSA). Results: Of the 113 bypass surgeries performed, 68 had pre-operative VMR and DSA. A total of 52 patients were included, in which 16 had both hemispheres operated on (median age 46 [IQR 25], 74% women, 60% with Moya-Moya disease, 51% presented with ischemic stroke, 37% TIA, 10% intracerebral hemorrhage and 1% headache). Pre-operatively, 97% had an abnormal VMR, 24% had incomplete collateralization. A total of 79% had bypass patency (87% immediate, 76% delayed, median time 1 year 8 months [IQR 1 year and 6 months)) on follow up. Patients with patent bypass had significantly lower VMR (27 [SD ± 18.8] vs. mean 36 [SD ± 14.5], p=0.005) and higher likelihood of incomplete collateralization pre-operatively (mean 25.1 [SD ± 16.4] vs. mean 39.2 [SD ± 18.8], p=0.013) as compared to non-patent bypass patients. In multivariate analysis low pre-operative VMR was a significant predictor for bypass patency adjusting for age, presenting stroke type and gender (p=0.01). Conclusion: Vasomotor reactivity is a non-invasive, low-cost test which predicted angiographic vessel collateralization and bypass patency. Bypass patency remains important predictor of outcomes in this population.

Five-Day Bed Rest Reduces Postoperative Intracerebral Hemorrhage After Direct Bypass for Moyamoya Disease

Postoperative intracerebral hemorrhage (ICH) after direct bypass surgery for Moyamoya disease could contribute to neurologic deterioration. The aim of this study was to evaluate the effectiveness of 5-day bed rest in reducing the occurrence of postoperative ICH. This study included 122 consecutive hemispheres in 87 Japanese adult MMD patients, composed of 80 control hemispheres from historical data and 42 hemispheres after 5-day bed rest. They all underwent direct bypass surgery. The incidence of postoperative ICH and neurologic deterioration assessed via the modified Rankin Scale were investigated and statistically analyzed. Postoperative ICH was observed in 9 out of the 80 (11.3%) control patients, but not in the 42 patients with 5-day bed rest. The incidence of postoperative ICH and neurologic deterioration via the modified Rankin Scale were significantly different between the 2 groups (P= 0.0268 and 0.0078, respectively). Univariate logistic analysis revealed that 5-day bed rest significantly reduced the incidence of postoperative ICH (P= 0.0048). Five-day bed rest after direct bypass surgery dramatically can reduce the incidence of postoperative ICH and neurologic deterioration after direct bypass surgery.