Prediction of postoperative cerebral infarction after combined bypass surgery in adult moyamoya disease: combining quantitative parameters on RAPID perfusion CT with clinically related factors

OBJECTIVE

The aim of this study was to identify predictive factors of postoperative cerebral infarction (PostCI) following combined bypass (CB) surgery in adult patients with moyamoya disease (MMD) using quantitative parameters from the rapid processing of perfusion and diffusion (RAPID) perfusion CT (PCT) software.

METHODS

The authors retrospectively reviewed 276 total hemispheres in patients with MMD who underwent CB. Preoperative volumes of time-to-maximum (Tmax) > 4 sec and > 6 sec were obtained from the RAPID analysis of PCT. These quantitative parameters, along with other clinical and angiographic factors, were statistically analyzed to determine the significant predictors for PostCI following CB.

RESULTS

PostCI occurred in 17 hemispheres (6.16%). PCA involvement (p = 0.016), and the volume of Tmax > 6 sec (p < 0.001) and Tmax > 4 sec (p < 0.001), were identified as variables related to PostCI in the univariable analysis. In the multivariable analysis, the volume of Tmax > 6 sec (OR 1.013, 95% confidence interval 1.007-1.019, p < 0.001) was determined to be an independent predictive factor significantly associated with PostCI after CB in adult patients with MMD. In the receiver operating characteristic (ROC) curve, the cutoff value of the preoperative volume of Tmax > 6 sec was determined to be 59.5 ml (sensitivity 82.4%, specificity 71.9%, area under the ROC curve 0.811).

CONCLUSIONS

For adult patients with MMD and a large volume of Tmax > 6 sec over 59.5 ml, more caution is required when deciding to undergo bypass surgery and in postoperative management.

Relationship between in-stent restenosis following carotid artery stenting and platelet reactivity to clopidogrel

OBJECTIVE

To analyze the relationship between in-stent restenosis (ISR) following carotid artery stenting (CAS) and platelet clopidogrel reactivity confirmed by the P2Y12 reaction unit (PRU) and inhibition rate (IR).

METHODS

We retrospectively analyzed 171 patients who underwent CAS with extracranial carotid stenosis from January 2016 to December 2019. Dual antiplatelet therapy with 100 mg aspirin and 75 mg clopidogrel was started ≥5 days before CAS. Clopidogrel resistance was measured with the PRU and IR the day before CAS. The ISR degree was classified into R1, R2, and R3 (moderate to severe luminal stenosis of ≥50% or occlusion) by carotid CT angiography after 24-30 months. The degree of quantitative association between platelet reactivity and ISR R3 was determined by the receiver operating characteristic curve method. The optimal cut-off values of PRU and IR were derived using the maximum Youden index.

RESULTS

There were 33 R3 degrees of ISR (19.3%) and nine ipsilateral ischemic strokes (5.3%). The PRU and IR were different between R1+R2 degrees (176.4±50.1, 27.5±18.7%) and R3 degree (247.5±55.0, 10.3±13.4%) (P<0.001). The areas under the curves of PRU and IR were 0.841 and 0.781, and the optimal cut-off values were 220.0 and 14.5%, respectively. Multivariate logistic regression analysis showed that PRU ≥220 and IR ≤14.5% were significant predictive factors for ISR R3 (P<0.001 and P=0.017, respectively). ISR R3 was independently associated with ipsilateral ischemic stroke after CAS (P=0.012).

CONCLUSIONS

High PRU (≥220) and low IR (≤14.5%) are related to ISR R3 following CAS, which may cause ipsilateral ischemic stroke.

Optimal blood pressure for stroke prevention in healthy adults below 65 years: A nationwide 10-year observational study

BACKGROUND

There have been few reports on the preventative value of intensive blood pressure (BP) management for stroke since the American College of Cardiology/American Heart Association (ACC/AHA) announced the new criteria for hypertension (HTN) in 2017. This study aimed to identify optimal BP for prevention of stroke in healthy adults under 65 years.

METHODS

We conducted a 10-year observational study on the risk of stroke, subclassified as hemorrhagic stroke (HS) or ischemic stroke (IS), according to BP categories (low-normal BP, high-normal BP, elevated BP, stage 1 HTN, and stage 2 HTN) using the National Health Insurance Service Database.

RESULTS

In 2008, a health checkup was conducted for a total of 8,327,751 participants, and 949,551 of them enrolled in this study. The risk of HS increased from stage 2 HTN (adjusted hazard ratio [AHR], 3.036 [95 % confidence interval [CI], 2.159-4.252]) in men to stage 1 HTN (AHR, 2.972; 95 % CI, 2.256-3.897) in women. The risk of IS increased in both men (AHR, 1.404 [95 % CI, 1.164-1.693]) and women (AHR, 2.012 [95 % CI, 1.603-2.526]) with stage 1 HTN. The overall risk of stroke increased in men (AHR, 1.386; [95 % CI, 1.180-1.629]) and women (AHR, 2.363 [95 % CI, 1.973-2.830]) with stage 1 HTN.

CONCLUSION

This study underscores the importance of maintaining BP below Stage 1 HTN to prevent stroke in healthy adults aged below 65 years. These findings highlight the significance of the new HTN guidelines established by the ACC/AHA in 2017.

Angiographic and clinical outcomes of various techniques of intracranial-to-intracranial bypasses for complex cases with a review of pertinent literature and illustrated cases

OBJECTIVE

Determine the utility of intracranial-to-intracranial bypass (IIB) surgery for complex cases and bypass options.

METHODS

Eighteen IIB cases were included. Each case was classified as IIB with interposition grafts and non-interposition grafts. Clinical and angiographical status were evaluated pre- and postoperatively and at the last follow-up. Angiographic images were analyzed and schematically drawn. Postoperative angiography was used to measure the bypass patency and the presence of postoperative cerebral infarction. Recipient artery occlusion time of each bypass was measured.

RESULTS

14 cases were complex intracranial aneurysms (IAs), 1 case was vertebrobasilar dolichoectasia, and 3 cases were intracranial arterial steno-occlusive disease (ICAS). 10 patients had incidental discovered IAs, and 7 patients presented with neurological deficits due to ischemia or aneurysmal mass effects. 10 cases were IIB with interposition grafts, including 4 cases of superficial temporal artery (STA) and 6 cases of radial artery graft (RAG) bypass. Eight cases were IIB with non-interposition grafts, including 3 cases of in situ bypass, 1 case of reanastomosis, and 4 cases of reimplantation. The pre- and postoperative mRS were not changed or improved, and all the bypasses were patent. There was no mortality during the mean follow-up period of 50.0 months. Mean occlusion time of recipient artery was 59.5 min. Total 8 patients had postoperative cerebral infarction but almost recovered at the discharge period.

CONCLUSIONS

With the proper selection of the IIB type, IIB surgery can be a suitable treatment option for some patients with complex IAs and ICAS when extracranial-to-intracranial bypass is not feasible.

Clinical Outcomes of Coil Embolization for Unruptured Intracranial Aneurysms Categorized by Region and Hospital Size : A Nationwide Cohort Study in Korea

OBJECTIVE

To analyze the outcomes of coil embolization (CE) for unruptured intracranial aneurysm (UIA) according to region and hospital size based on National Health Insurance Service data in South Korea.

METHODS

The incidence of complications, including intracranial hemorrhage (ICRH) and cerebral infarction (CI), occurring within 3 months and the 1-year mortality rates in UIA patients who underwent CE in 2018 were analyzed. Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs) or semigeneral hospitals (sGHs) according to their size, and the administrative districts of South Korea were divided into 15 regions.

RESULTS

In 2018, 8425 (TRGHs, 4438; GHs, 3617; sGHs, 370) CEs were performed for UIAs. Complications occurred in 5.69% of patients seen at TRGHs, 13.48% at GHs, and 20.45% at sGHs. The complication rate in TRGHs was significantly lower than that in GHs (p=0.039) or sGHs (p=0.005), and that in GHs was significantly lower than that in sGHs (p=0.030). The mortality rates in TRGHs, GHs, and sGHs were 0.81%, 2.16%, and 3.92%, respectively, with no significant difference. Despite no significant difference in the mortality rates, the complication rate significantly increased as the number of CE procedures per hospital decreased (p=0.001; rho=-0.635). Among the hospitals where more than 30 CEs were performed for UIAs, the incidence of CIs (p=0.096, rho=-0.205) and the mortality rates (3 months, p=0.048, rho=-0.243; 1 year, p=0.009, rho=-0.315) significantly decreased as the number of CEs that were performed increased and no significant difference in the incidence of post-CE ICRH was observed.

CONCLUSION

The complication rate in patients who underwent CE for UIA increased as the hospital size and physicians' experience in conducting CEs decreased. We recommend nationwide quality control policies CEs for UIAs.

Optimal target blood pressure for the primary prevention of hemorrhagic stroke: a nationwide observational study

Background

There are few reports on the preventative value of intensive blood pressure (BP) management for stroke, especially hemorrhagic stroke (HS), after new criteria for hypertension (HTN) were announced by the American College of Cardiology/American Heart Association in 2017.

Aims

This study aimed to identify the optimal BP for the primary prevention of HS in a healthy population aged between 20 and 65 years.

Methods

We conducted a 10-year observational study on the risk of HS, subclassified as intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) according to BP categories (e.g., low normal BP, high normal BP, elevated BP, stage 1 HTN, and stage 2 HTN) using the National Health Insurance Service Database.

Results

Out of 8,327,751 participants who underwent a health checkup in 2008, 949,550 were included in this study and observed from 2009 to 2018. The risk of ICH was significantly increased in men with stage 2 HTN {adjusted hazard ratio [aHR] 2.002 [95% confidence interval (CI) 1.203-3.332]} and in women with stage 1 HTN [aHR 2.021 (95% CI, 1.251-3.263)]. The risk of SAH was significantly increased in both men [aHR 1.637 (95% CI, 1.066-2.514)] and women [aHR 4.217 (95% CI, 2.648-6.715)] with stage 1 HTN. Additionally, the risk of HS was significantly increased in men with stage 2 HTN [aHR 3.034 (95% CI, 2.161-4.260)] and in women with stage 1 HTN [aHR 2.976 (95% CI, 2.222-3.986)].

Conclusion

To prevent primary HS, including ICH and SAH, BP management is recommended for adults under the age of 65 years with stage 1 HTN.

Validation of prediction algorithm for risk estimation of intracranial aneurysm development using real-world data

Intracranial aneurysm (IA) is difficult to detect, and most patients remain undiagnosed, as screening tests have potential risks and high costs. Thus, it is important to develop risk assessment system for efficient and safe screening strategy. Through previously published research, we have developed a prediction model for the incidence risk of IA using cohort observational data. This study was designed to verify whether such a prediction model also demonstrates sufficient clinical performance in predicting the prevalence risk at the point of health screening, using cross-sectional data. The study population comprised individuals who visited the Chonnam National University Hwasun Hospital Health Promotion Center in Korea for voluntary medical checkups between 2007 and 2019. All participants had no history of cerebrovascular disease and underwent brain CTA for screening purpose. Presence of IA was evaluated by two specialized radiologists. The risk score was calculated using the previously developed AI model, and 0 point represents the lowest risk and 100 point represents the highest risk. To compare the prevalence according to the risk, age-sex standardization using national database was performed. A study collected data from 5942 health examinations, including brain CTA data, with participants ranging from 20 to 87 years old and a mean age of 52 years. The age-sex standardized prevalence of IA was 3.20%. The prevalence in each risk group was 0.18% (lowest risk, 0-19), 2.12% (lower risk, 20-39), 2.37% (mid-risk, 40-59), 4.00% (higher risk, 60-79), and 6.44% (highest risk, 80-100). The odds ratio between the lowest and highest risk groups was 38.50. The adjusted proportions of IA patients in the higher and highest risk groups were 26.7% and 44.5%, respectively. The median risk scores among IA patients and normal participants were 74 and 54, respectively. The optimal cut-off risk score was 60.5 with an area under the curve of 0.70. We have confirmed that the incidence risk prediction model built through machine learning also shows viable clinical performance in predicting prevalence risk. By utilizing this prediction system, we can effectively predict not only the incidence risk but also the prevalence risk, which is the probability of already having the disease, using health screening data. This may enable us to consider strategies for the early detection of intracranial aneurysms.

Long-term outcomes and quantitative radiologic analysis of extracranial-intracranial bypass for hemodynamically compromised chronic large artery occlusive disease

This study aimed to demonstrate the effectiveness of nonemergent extracranial-to-intracranial bypass (EIB) in symptomatic chronic large artery atherosclerotic stenosis or occlusive disease (LAA) through quantitative analysis of computed tomography perfusion (CTP) parameters using RAPID software. We retrospectively analyzed 86 patients who underwent nonemergent EIB due to symptomatic chronic LAA. CTP data obtained preoperatively, immediately postoperatively (PostOp0), and 6 months postoperatively (PostOp6M) after EIB were quantitatively analyzed through RAPID software, and their association with intraoperative bypass flow (BF) was assessed. The clinical outcomes, including neurologic state, incidence of recurrent infarction and complications, were also analyzed. The time-to-maximum (Tmax) > 8 s, > 6 s and > 4 s volumes decreased significantly at PostOp0 and up through PostOp6M (preoperative, 5, 51, and 223 ml (median), respectively; PostOp0, 0, 20.25, and 143 ml, respectively; PostOp6M, 0, 7.5, and 148.5 ml, respectively; p < 0.001, p < 0.001, and p < 0.001, respectively). The postoperative improvement in the Tmax > 6 s and > 4 s volumes was significantly correlated with the BF at PostOp0 and PostOp6M (PostOp0, r = 0.367 (p = 0.001) and r = 0.275 (p = 0.015), respectively; PostOp6M r = 0.511 (p < 0.001) and r = 0.391 (p = 0.001), respectively). The incidence of recurrent cerebral infarction was 4.7%, and there were no major complications that produced permanent neurological impairment. Nonemergent EIB under strict operation indications can be a feasible treatment for symptomatic, hemodynamically compromised LAA patients.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Implantation of Acellular Dermal Matrix to Prevent Frontotemporal Depression Following Minipterional Craniotomy for the Surgical Clipping of Unruptured Intracranial Aneurysms

OBJECTIVE

The objective of the study was to assess the esthetic efficacy of acellular dermal matrix (ADM) implantation to prevent frontotemporal depression (FTD) following minipterional craniotomy (MPT) to clip unruptured intracranial aneurysms.

METHODS

We retrospectively compared the incidence of FTD in 100 patients treated without ADM from March to July 2019 and 100 patients treated with ADM from August to December 2019. ADM was implanted in the interfascial layer to cover the temporalis muscle. The specific location and degree of FTD were analyzed by measuring the thickness and area of multiple points (P1-P12) and regions (S1-S3) through brain computed tomography preoperatively and 1 year postoperatively.

RESULTS

In the non-ADM group, the thickness at P1, P2, P5, P6, and P9 was reduced and the area of S1 and S2 was smaller after surgery than before surgery (P < 0.05), similar to the incision and suture site of the temporalis muscle. However, in the ADM group, the preoperative and postoperative measurements were not different. FTD recognition was significantly lower in the ADM group (6.0%) than that in the non-ADM group (17.0%) (P = 0.015) and occurred in the retroorbital region through P1, P2, P5, and P6, with the area under the receiver operating characteristic curves of 0.840, 0.766, 0.811, and 0.751, respectively. ADM implantation was the only significant predictive factor for FTD recognition in multivariate logistic regression analysis (odds ratio = 0.30; 95% confidence interval: 0.11-0.79; P = 0.015).

CONCLUSIONS

Even MPT cannot completely prevent FTD in the retroorbital region. ADM implantation in MPT can help to improve esthetic satisfaction.

Quantitative radiological analysis and clinical outcomes of urgent EC-IC bypass for hemodynamic compromised patients with acute ischemic stroke

This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion (CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software. Short- and long-term clinical outcomes, including complications and neurological status, were also analyzed. Postoperatively, the volume of time-to-max (Tmax) > 6 s decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 78 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 7 ml; p = 0.000). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 72 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 5 ml; p = 0.000). In addition, the patients' neurological condition improved significantly (p < 0.001). Only one patient (2.3%) showed progression of infarction. Urgent EIB using strict indications can be a feasible treatment for IAT-ineligible patients with AIS due to large vessel occlusion or stenosis.

Heavily T2-Weighted Magnetic Resonance Myelography as a Safe Cerebrospinal Fluid Leakage Detection Modality for Nontraumatic Subdural Hematoma

Objective

Nontraumatic subdural hematoma (SDH) is a common disease, and spinal cerebrospinal fluid (CSF) leakage is a possible etiology of unknown significance, which is commonly investigated by several invasive studies. This study demonstrates that heavily T2-weighted magnetic resonance myelography (HT2W-MRM) is a safe and clinically effective imaging modality for detecting CSF leakage in patients with nontraumatic SDH.

Methods

All patients who underwent HT2W-MRM for nontraumatic SDH workup at our institution were searched and enrolled in this study. Several parameters were measured and analyzed, including patient demographic data, initial modified Rankin Scale (mRS) score upon presentation, SDH bilaterality, hematoma thickness upon presentation, CSF leakage sites, treatment modalities, followup hematoma thickness, and follow-up mRS score.

Results

Forty patients were identified, of which 22 (55.0%) had CSF leakage at various spinal locations. Five patients (12.5%) showed no change in mRS score, whereas the remaining (87.5%) showed decreases in follow-up mRS scores. In terms of the overall hematoma thickness, four patients (10.0%) showed increased thickness, two (5.0%) showed no change, 32 (80.0%) showed decreased thickness, and two (5.0%) did not undergo follow-up imaging for hematoma thickness measurement.

Conclusion

HT2W-MRM is not only safe but also clinically effective as a primary diagnostic imaging modality to investigate CSF leakage in patients with nontraumatic SDH. Moreover, this study suggests that CSF leakage is a common etiology for nontraumatic SDH, which warrants changes in the diagnosis and treatment strategies.

Mediation effects of mean Hounsfield unit on relationship between hemoglobin and expansion of intracerebral hemorrhage

Low hemoglobin levels are known to be associated with hematoma expansion (HE) and poor functional outcome in patients with intracerebral hemorrhage (ICH). However, it is not yet known whether low hemoglobin itself causes HE directly or is merely a confounder. Thus, we investigated the mediation effect of the mean Hounsfield unit (HU) of hematoma on the relationship between low hemoglobin and expansion of ICH. Overall, 232 consecutive patients with ICH who underwent non-contrast computed tomography (NCCT) within 12 h since onset were included. The mean HU and hematoma volume on NCCT were investigated using semi-automated planimetry. HE was defined as an increase in hematoma volume > 33% or 6 mL. The respective associations among the hemoglobin level, mean HU, and HE were analyzed using multivariable regression analysis, adjusting for age, sex, and known HE predictors. Mediation analysis was performed to examine the potential causal association among the three. HE occurred in 34.5% of patients; hemoglobin levels were inversely associated with HE occurrence (adjusted odds ratio, 0.90; p = 0.03). The mean HU of the hematoma was lower in patients with HE than in patients without HE (58.5 ± 3.3 vs. 56.8 ± 3.0; p < 0.01). Hemoglobin levels on admission were linearly related to the mean HU (adjusted β, 0.33; p < 0.01) after adjusting for known HE predictors (time from onset to CT, antithrombotic use, hematoma volume). Causal mediation analysis showed a significant mediation effect of the mean HU on the association between hemoglobin levels and HE (p = 0.04). The proportion of indirect effect through the mean HU among the total effect was 19% (p = 0.05). The mediation effect became nonsignificant in the when the multivariable model was adjusted with additional covariates (baseline systolic blood pressure and hematoma location). The mean HU of the hematoma mediated the association between hemoglobin levels and HE occurrence. Therefore, the mean HU of the hematoma may be a potential marker of impaired hemostasis in patients with ICH.

The inhibition rate estimated using VerifyNow can help to predict the thromboembolic risk of coil embolization for unruptured intracranial aneurysms

BACKGROUND

The role of the inhibition rate of VerifyNow in assessing the thromboembolic risk of coil embolization for unruptured intracranial aneurysms is unclear.

OBJECTIVE

To carry out a retrospective study to determine whether the inhibition rate could provide additional help in predicting thromboembolic events when it was used for patients with a P2Y12 reaction unit (PRU) level of 220 or lower.

METHODS

Patients who underwent coil embolization for unruptured aneurysms with an appropriate PRU level (PRU 220 or lower) between January 1, 2015 and December 31, 2018 were analyzed. A total of 954 patients with 1020 aneurysms were included in this study. The primary outcome was the thromboembolic events occurring within 30 days after coil embolization. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were obtained to determine the quantitative predictive ability of the inhibition rate. The optimal cut-off value was derived using the Youden index.

RESULTS

Thromboembolic events developed in 11 patients (1.08% of 1020 procedures). The AUC of the ROC curve was 0.83. The optimal cut-off value of the inhibition rate derived using the maximum Youden index was 22.0%. A sensitivity test using a multiple logistic regression analysis demonstrated that the inhibition rate was a significant variable for predicting thromboembolic events.

CONCLUSIONS

The inhibition rate can be used to determine high thromboembolic risks for patients with PRU levels of 220 or lower. The optimal cut-off value of the inhibition rate was 22.0% when the PRU level was 220 or less.

Higher oscillatory shear index is related to aneurysm recanalization after coil embolization in posterior communicating artery aneurysms

BACKGROUND

The recurrence rate of posterior communicating artery (Pcom) aneurysms after endovascular treatment (EVT) is higher than that for aneurysms located in other sites. However, it is still unclear what mechanisms are responsible for the recanalization of cerebral aneurysms. In this investigation, we compared hemodynamic factors related with recanalization of Pcom aneurysms treated by endoluminal coiling using computational fluid dynamics (CFD) with high-resolution three-dimensional digital subtraction angiography images.

METHODS

Twenty patients were enrolled. A double-sinogram acquisition was performed with and without contrast injection after coil embolization to get true blood vessel lumen by relatively complementing the first sinogram with the second. Adaptive Cartesian meshing was performed to produce vascular wall objects for CFD simulation. The boundary condition for inlet (ICA) was set for dynamic velocity according to the cardiac cycle (0.8 s). Hemodynamic parameters were recorded at two specific points (branching point of Pcom and residual sac). The peak pressure, peak WSS, and oscillatory shear index (OSI) were recorded and analyzed.

RESULTS

The median age was 61.0 years, and 18 patients (90%) were female. During a median follow-up of 12 months, seven (35%) treated aneurysms showed recanalization. The median aneurysm volume was significantly higher, and aneurysm height and neck sizes were significantly longer in the recanalization group than those in the stable group. At the branching point of the Pcom, the peak pressure, peak WSS, or OSI did not significantly differ between the two groups. The only statistically significant hemodynamic parameter related with recanalization was the OSI at the aneurysm point. Multivariate logistic regression showed that with an increase of 0.01 OSI at the aneurysm point, the odds ratio for the aneurysm recanalization was 1.19.

CONCLUSIONS

A higher OSI is related with recanalization after coil embolization for a Pcom aneurysm.

Clinical Outcomes of Clipping and Coiling in Elderly Patients with Unruptured Cerebral Aneurysms: a National Cohort Study in Korea

BACKGROUND

We aimed to analyze outcomes of clipping and coiling in treating unruptured intracranial aneurysms (UIAs) in elderly patients and to identify the age at which perioperative risk increases based on national cohort data in South Korea.

METHODS

The incidence of perioperative intracranial hemorrhage (ICRH), perioperative cerebral infarction (CI), mortality, and moderate to severe disability data of the patients who underwent coiling or clipping for UIAs were retrieved. Estimated breakpoint (EBP) was calculated to identify the age at which the risk of treatment increases.

RESULTS

A total of 38,207 patients were treated for UIAs. Among these, 22,093 (57.8%) patients underwent coiling and 16,114 (42.2%) patients underwent clipping. The incidence of ICRH, requiring a secondary operation, within 3 months in patients ≥ 65 years that underwent coiling and clipping was 1.13% and 4.81%, respectively, and that of both groups assessed were significantly higher in patients ≥ 75 years (coiling, P = 0.013, relative risk (RR) 1.81; clipping, P = 0.015) than younger patients. The incidence of CI within 3 months in patients aged ≥ 65 was 13.90% and 9.19% in the coiling and clipping groups, respectively. The incidence of CI after coiling in patients aged ≥ 75 years (P < 0.001, RR 1.96) and after clipping in patients aged ≥ 70 years (P < 0.001, RR 1.76) was significantly higher than that in younger patients. The mortality rates within 1 year in patients with perioperative ICRH or CI were 2.41% and 3.39% for coiling and clipping groups, respectively, in patients ≥ 65. These rates increased significantly at age 70 in the coiling group and at age 75 for the clipping group (P = 0.012 and P < 0.001, respectively).

CONCLUSION

The risk of treatment increases with age, and this risk increases dramatically in patients aged ≥ 70 years. Therefore, the treatment decisions in patients aged ≥ 70 years should be made with utmost care.

Classification of cardioembolic stroke based on a deep neural network using chest radiographs

BACKGROUND

Although chest radiographs have not been utilised well for classifying stroke subtypes, they could provide a plethora of information on cardioembolic stroke. This study aimed to develop a deep convolutional neural network that could diagnose cardioembolic stroke based on chest radiographs.

METHODS

Overall, 4,064 chest radiographs of consecutive patients with acute ischaemic stroke were collected from a prospectively maintained stroke registry. Chest radiographs were randomly partitioned into training/validation (n = 3,255) and internal test (n = 809) datasets in an 8:2 ratio. A densely connected convolutional network (ASTRO-X) was trained to diagnose cardioembolic stroke based on chest radiographs. The performance of ASTRO-X was evaluated using the area under the receiver operating characteristic curve. Gradient-weighted class activation mapping was used to evaluate the region of focus of ASTRO-X. External testing was performed with 750 chest radiographs of patients with acute ischaemic stroke from 7 hospitals.

FINDINGS

The areas under the receiver operating characteristic curve of ASTRO-X were 0.86 (95% confidence interval [CI], 0.83-0.89) and 0.82 (95% CI, 0.79-0.85) during the internal and multicentre external testing, respectively. The gradient-weighted class activation map demonstrated that ASTRO-X was focused on the area where the left atrium was located. Compared with cases predicted as non-cardioembolism by ASTRO-X, cases predicted as cardioembolism by ASTRO-X had higher left atrial volume index and lower left ventricular ejection fraction in echocardiography.

INTERPRETATION

ASTRO-X, a deep neural network developed to diagnose cardioembolic stroke based on chest radiographs, demonstrated good classification performance and biological plausibility.

FUNDING

Grant No. 14-2020-046 and 08-2016-051 from the Seoul National University Bundang Research Fund and NRF-2020M3E5D9079768 from the National Research Foundation of Korea.

Intravenous Fluid Selection for Unruptured Intracranial Aneurysm Clipping : Balanced Crystalloid versus Normal Saline

OBJECTIVE

While balanced crystalloid (BC) could be a relevant fluid regimen with buffer system compared with normal saline (NS), there have been no studies on the optimal fluid for surgery of an unruptured intracranial aneurysm (UIA). This study aimed to compare the effects of fluid regimens between NS and BC on the metabolic and clinical outcomes of patients who underwent surgery for UIA.

METHODS

This study was designed as a propensity score matched retrospective comparative study and included adult patients who underwent UIA clipping. Patient groups were categorized as NS and BC groups based on the types of pre-operative fluid and the amount of fluid administered during surgery. The primary outcomes were defined as electrolyte imbalance and acidosis immediately after surgery. The secondary outcomes were the length of stay in the intensive care unit (ICU) and duration from the end of the operation to extubation.

RESULTS

A total of 586 patients were enrolled in this study, with each of 293 patients assigned to the NS and BC groups, respectively. Immediately after surgery, serum chloride levels were significantly higher in the NS group. Compared to the NS group, the BC group had lower incidence rates of acidemia (6.5% vs. 11.6%, p=0.043) and metabolic acidosis (0.7% vs. 4.4%, p=0.007). As compared to NS group, BC group had significantly shorter duration from the end of the operation to extubation (250±824 vs. 122±372 minutes, p=0.016) and length of stay in ICU (1.37±1.11 vs. 1.12±0.61 days, p=0.001). Throughout multivariable analysis, use of BC was found to be significant factor for favorable post-operative results.

CONCLUSION

This study showed that the patients who received BC during UIA clipping had lower incidence of metabolic acidosis, earlier extubation and shorter ICU stay compared to those who received NS. Therefore, using BC as a peri-operative fluid can be recommended for patients who undergo surgery for UIA.

Prediction of Intracranial Aneurysm Risk using Machine Learning

An efficient method for identifying subjects at high risk of an intracranial aneurysm (IA) is warranted to provide adequate radiological screening guidelines and effectively allocate medical resources. We developed a model for pre-diagnosis IA prediction using a national claims database and health examination records. Data from the National Health Screening Program in Korea were utilized as input for several machine learning algorithms: logistic regression (LR), random forest (RF), scalable tree boosting system (XGB), and deep neural networks (DNN). Algorithm performance was evaluated through the area under the receiver operating characteristic curve (AUROC) using different test data from that employed for model training. Five risk groups were classified in ascending order of risk using model prediction probabilities. Incidence rate ratios between the lowest- and highest-risk groups were then compared. The XGB model produced the best IA risk prediction (AUROC of 0.765) and predicted the lowest IA incidence (3.20) in the lowest-risk group, whereas the RF model predicted the highest IA incidence (161.34) in the highest-risk group. The incidence rate ratios between the lowest- and highest-risk groups were 49.85, 35.85, 34.90, and 30.26 for the XGB, LR, DNN, and RF models, respectively. The developed prediction model can aid future IA screening strategies.

Characteristics and Clinical Course of Fusiform Middle Cerebral Artery Aneurysms According to Location, Size, and Configuration

OBJECTIVE

To analyze the angiographic features and clinical course, including treatment outcomes and the natural course, of fusiform middle cerebral artery aneurysms (FMCAAs) according to their location, size, and configuration.

METHODS

We reviewed the literature on adult cases of FMCAAs published from 1980 to 2018; from 25 papers, 112 FMCAA cases, for which the location, size, and configuration could be identified, were included in this study. Additionally, 33 FMCAA cases in our hospital were included, from which 16 were assigned to the observation group. Thus, a total of 145 adult FMCAA cases were included. We classified the FMCAAs according to their location (l-type 1, beginning from prebifurcation; l-type 2, beginning from bifurcation; l-type 3, beginning from postbifurcation), size (small, <10 mm; large, ≥10 mm; giant, ≥25 mm), and configuration (c-type 1, classic dissecting aneurysm; c-type 2, segmental ectasia; c-type 3, dolichoectatic dissecting aneurysm).

RESULTS

The c-type 3 was more commonly diagnosed with ischemic symptoms (31.8%) than hemorrhage (13.6%), while 40.9% were found accidentally. In contrast, c-type 2 was more commonly diagnosed with hemorrhagic symptoms (14.9%) than ischemic symptoms (10.6%), and 72.3% were accidentally discovered. According to location, ischemic symptoms and hemorrhage were the most frequent symptoms in l-type 1 (28.6%) and l-type 3 (34.6%), respectively. Most of l-type 2 FMCAAs were found incidentally (68.4%). Based on the size of FMCAAs, only 11.1% of small aneurysms were found to be hemorrhagic, while 18.9% and 26.0% of large and giant aneurysms were hemorrhagic, respectively. Although four aneurysms of the 16 FMCAAs in the observation group increased in size and one aneurysm decreased in size during the observation period, no rupture was seen in any case and there were no significant predictors of aneurysm enlargement. Of 104 FMCAAs treated, 14 cases (13.5%) were aggravated than before surgery and all the aggravated cases were l-type 1.

CONCLUSION

While ischemic symptoms occurred more frequently in l-type 1 and c-type 3, hemorrhagic rather than ischemic symptoms occurred more frequently in l-type 3 and c-type 2. In case of l-type 1 FMCAAs, more caution is required in determining the treatment due to the relatively high complication rate.

Residual stenosis after carotid artery stenting: Effect on periprocedural and long-term outcomes

Objective

This study investigated the effect of residual stenosis after carotid artery stenting (CAS) on periprocedural and long-term outcomes.

Methods

Patients treated with CAS for symptomatic or asymptomatic carotid arterial stenosis were consecutively enrolled. Residual stenosis was estimated from post-procedure angiography findings. The effects of residual stenosis on 30-day periprocedural outcome and times to restenosis and clinical outcome were analyzed using logistic regression models and Wei-Lin-Weissfeld models, respectively.

Results

A total of 412 patients (age, 64.7 ± 17.0 years; male, 82.0%) were enrolled. The median baseline stenosis was 80% (interquartile range [IQR], 70–90%), which improved to 10% (0–30%) for residual stenosis. Residual stenosis was significantly associated with periprocedural outcome (adjusted odds ratio, 0.983; 95% confidence interval [CI], 0.965–0.999, P = 0.01) after adjustment for baseline stenosis, age, hypertension, symptomaticity, and statin use. Over the 5-year observation period, residual stenosis did not increase the global hazard for restenosis and clinical outcome (adjusted hazard ratio, 1.011; 95% CI, 0.997–1.025. In the event-specific model, residual stenosis increased the hazard for restenosis (adjusted hazard ratio, 1.041; 1.012–1.072) but not for clinical outcome (adjusted hazard ratio, 1.011; 0.997–1.025).

Conclusions

Residual stenosis after carotid artery stenting may be useful to predict periprocedural outcome and restenosis.

Intraoperative neuromonitoring during microsurgical clipping for unruptured anterior choroidal artery aneurysm

OBJECTIVE

To investigate the safety and unexpected finding of the intraoperative neuromonitoring (IONM) including somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) during microsurgical clipping of an unruptured anterior choroidal artery (AChA) aneurysm.

PATIENTS AND METHODS

From January 2011 to March 2018, the neurophysiological, clinical, and radiological data of 115 patients who underwent microsurgical clipping for an unruptured AChA aneurysm under IONM were retrospectively analyzed. The incidence of ischemic complications after microsurgical clipping of unruptured AChA aneurysms as well as the false-negative rate, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of IONM during surgery were calculated.

RESULTS

Ischemic complications after the microsurgical clipping of an AChA aneurysm under IONM occurred in 7 of 115 patients (6.08%). Among them, 3 were symptomatic (2.6%). The false-negative rate of IONM for ischemic complications was 6.08% (7 patients). High specificity; 100% (95% confidence interval [95% CI] = 0.972-1.000), PPVs; 100% (95% CI = 0.055-1.000), and NPVs; 93% (95% CI = 0.945-0.973) with low sensitivity; 11.1% (95% CI = 0.006-0.111) were calculated.

CONCLUSIONS

IONM including transcranial MEP during microsurgical clipping of unruptured AChA aneurysm might have limited usefulness. Therefore, other MEP monitoring using direct cortical stimulation or modified transcranial methodology should be considered to compensate for it.

Trends in Incidence and Treatment of Herniated Lumbar Disc in Republic of Korea : A Nationwide Database Study

OBJECTIVE

This study aimed to determine the incidence and analyze trends of the herniated lumbar disc (HLD) based on a national database in the Republic of Korea (ROK) from January 2008 to December 2016.

METHODS

This study was a retrospective analysis of data obtained from the national health-claim database provided by the National Health Insurance Service for 2008-2016 using the International Classification of Diseases. The crude incidence and age-standardized incidence of HLD were calculated, and additional analysis was conducted according to age and sex. Changes in trends in treatment methods and some treatments were analyzed using the Korean Classification of Diseases procedure codes.

RESULTS

The number of patients diagnosed with HLD was 472245 in 2008 and increased to 537577 in 2012; however, it decreased to 478697 in 2016. The pattern of crude incidence and the standardized incidence were also similar. Overall, the incidence of HLD increased annually for the 30s, 40s, 50s, and 70s until 2012 and then decreased. However, the incidence of HLD for the 80s continued to increase. The crude incidence of HLD in female patients exceeded that of male patients in their middle age (30s or 40s) and was 1.5-1.6 times higher than in male patients in their 60s. The total number of open discectomy (OD) increased from 71598 in 2008 to 93942 in 2012 and then decreased to 85846 in 2016. The rate of younger patients (the 20s, 30s, and 40s) who underwent OD was decreased, and the rate of younger patients who underwent percutaneous endoscopic lumbar discectomy was increased. However, the rate of older patients (the 70s and 80s) who underwent OD was continuously increased.

CONCLUSION

This nationwide data on HLD from 2008 to 2016 in the ROK demonstrated that the crude incidence and the standardized incidence increased until 2012 and then decreased. The annual crude incidence was different according to age and sex. These findings may be considered when deciding future health policy, especially in countries with a similar national health insurance system (or with plans to adopt).

Trends in the Incidence and Treatment of Cerebrovascular Diseases in Korea : Part I. Intracranial Aneurysm, Intracerebral Hemorrhage, and Arteriovenous Malformation

Objective

To analyze the incidence and treatment trends of hemorrhagic stroke (HS), according to HS subtypes, using nationwide data in Korea from January 2008 to December 2016.

Methods

We used data from the national health-claim database provided by the National Health Insurance Service for 2008–2016 using the International Classification of Diseases. The crude incidence and age-standardized incidence of each disease associated with HS, which included intracranial aneurysm (IA), hypertensive intracerebral hemorrhage (ICH), and arteriovenous malformation (AVM), were calculated and additional analysis was conducted according to age and sex. Changes in trends in treatment methods and number of treatments were analyzed for each cerebrovascular disease using the Korean Classification of Diseases procedure codes.

Results

In 2016, the total number of newly diagnosed adult patients with HS was 24169, showing a decrease by 7.0% since 2008; the age-standardized incidence of HS was 46.2 per 100000 person-years. The age-standardized incidence of unruptured IA (UIA) in adults was 71.4 per 100000 person-years—increased by 2.6-fold since 2008—while that of ruptured IA (RIA) was 12.6 per 100000 person-years, which had decreased at a rate of 20.3% since 2008. The number of coil embolization (CE) for UIA increased by 3.4-fold over 9 years and exceeded that of clipping since 2008. With respect to RIA, CE increased by 2.0-fold over 9 years and exceeded that of clipping from 2014. As for spontaneous ICH in adults, the age-standardized incidence was 31.3 per 100000 person-years in 2016—decreased by 34.7% since 2008—and 14.6% of patients diagnosed with ICH were treated in 2016, which was not significantly different from the proportion of patients treated since 2008. The age-standardized incidence of unruptured AVM (UAVM) was 2.0 per 100000 person-year in 2016, while that of ruptured AVM (RAVM) was 2.4 per 100000 person-years in 2016, showing a decreasing rate of 17.2% from 2008. The total number of treated patients with AVM declined since 2014.

Conclusion

In Korea, age-related cerebral vascular diseases, such as RIA, ICH, and RAVM, demonstrated a declining trend in agestandardized incidence; meanwhile, UIA and UAVM demonstrated an increased trend in both crude incidence and age-standardized incidence for 9 years. The increase in the elderly population, management of hypertension, and development of diagnostic and endovascular techniques appear to have influenced this trend.

Trends in the Incidence and Treatment of Cerebrovascular Diseases in Korea : Part II. Cerebral Infarction, Cerebral Arterial Stenosis, and Moyamoya Disease

OBJECTIVE

To analyze trends in the incidence and treatment of diseases associated with ischemic stroke, namely, cerebral infarction (CI), cerebral arterial stenosis (CASTN), and moyamoya disease (MMD), based on Korean National Health Insurance Service (NHIS) data from 2008 to 2016.

METHODS

Data was extracted from the national health-claim database provided by the NHIS for 2008-2016 using International Classification of Diseases codes. The crude and age-standardized incidences of each disease (CI, CASTN without a history of CI, and MMD) were calculated; additional analyses were conducted according to age and sex. Trends in the number of patients undergoing treatment according to treatment method were analyzed for each disease using the Korean Classification of Diseases procedure codes.

RESULTS

In 2016, the total number of adults with newly diagnosed CI was 83939, reflecting a 9.4% decrease from that in 2008. The agestandardized incidence of CI in adults was 153.2 per 100000 person-years in 2016, reflecting a 37.2% decrease from that in 2008, while that of CASTN was 167.3 per 100000 person-years in 2016, reflecting a 73.3% increase from that in 2008. Among treated cases, the number of patients who underwent intra-arterial (IA) treatment, including IA fibrinolysis and mechanical thrombectomy, showed the most prominent increase, increasing at an annual rate of 25.8%. For CASTN, the number of cases treated with carotid artery stenting or balloon angioplasty (CAS) showed the most prominent increase, increasing at a rate of 69.8% over the 9-year period. For MMD, the total number of patients with newly diagnosed MMD and that with adult MMD demonstrated significantly increasing trends, while the number of pediatric patients with newly diagnosed MMD declined by 18.0% over the 9-year period. The age-standardized incidences of pediatric and adult MMD in 2016 were 2.4 and 3.4 per 100000 person-years, respectively.

CONCLUSION

Although the incidence of CI showed a declining trend over a 9-year period, the number and proportion of patients treated for CI increased. Meanwhile, the incidence of CASTN and the number of patients treated for CASTN have demonstrated increasing trends since 2008. On the other hand, the number of patients diagnosed with pediatric MMD decreased, despite no significant change in the incidence. In contrast, the number of patients and the incidence of adult MMD increased. These trends reflect changes in the population structure, gains in the accessibility of imaging examinations, and the development of endovascular techniques.

Risk factors for preoperative and late postoperative seizures in primary supratentorial meningiomas

OBJECTIVE

We performed a retrospective study to identify factors associated with preoperative and late postoperative seizures in primary supratentorial meningiomas.

PATIENTS AND METHODS

Between July 2003 and December 2014, we extracted 303 consecutive patients who underwent primary resection for supratentorial meningiomas at a single institution. Univariate analysis and multivariate logistic regression analysis were performed to determine the associations of seizure occurrence and outcome.

RESULTS

Forty-nine (16.2%) of the total 303 patients presented with preoperative seizures. The risk factors independently associated with preoperative seizures were vasogenic edema (OR 4.44, p = 0.001), parasagittal or parafalcine location (OR 2.20, p = 0.020), and absence of neurologic deficit (OR 0.30, p = 0.003). Among these patients, 33 (67.3%) were seizure free postoperatively (Engel Class I). Of the 303 patients, we observed late postoperative seizures in 35 (11.6%) patients. The associated risk factors included history of preoperative seizure (OR 3.96, p = 0.002), bigger tumor size (OR 1.04, p = 0.002), and continuation of anti-epileptic drugs (OR 4.74, p = 0.001). We analyzed that meningiomas with a largest diameter of greater than 45.5 mm were 4.2 times more likely to have late postoperative seizures than those with less diameter (HR 4.20, p < 0.001). Ten (28.6%) of the 35 patients with late postoperative seizures experienced poor seizure control. The independently associated predictive factors were high grade meningiomas (WHO Grade II or III) (OR 10.66, p = 0.030) and history of postoperative adjuvant therapy (OR 12.58, p = 0.040).

CONCLUSIONS

Identifying factors associated with preoperative or late postoperative seizures may help guide treatment strategies, eventually improving the quality of life for patients with meningiomas.

Growth Pattern and Prognostic Factors of Untreated Nonfunctioning Pituitary Adenomas

Objective

Pituitary adenomas (PAs) are often detected as incidental findings. However, the natural history remains unclear. The objective of this study was to evaluate the natural history and growth pattern of untreated PAs.

Methods

Between 2003 and 2014, 59 PAs were managed with clinico-radiological follow up for longer than 12 months without any kind of therapeutic intervention. Tumor volumes were calculated at initial and last follow-up visit, and tumor growth during the observation period was determined. Data were analyzed according to clinical and imaging characteristics.

Results

The mean initial and last tumor volume and diameter were 1.83±2.97 mL and 13.77±6.45 mm, 2.85±4.47 mL and 15.75±8.08 mm, respectively. The mean annual tumor growth rate was 0.33±0.68 mL/year during a mean observation period of 46.8±32.1 months. Sixteen (27%) PAs showed tumor growth. The initial tumor size (HR, 1.140; 95% confidence interval, 1.003–1.295; p=0.045) was the independent predictive factor that determined the tumor growth. Six patients (11%) of 56 conservatively managed non-symptomatic PAs underwent resection for aggravating visual symptoms with mean interval of 34.5 months from diagnosis. By Cox regression analysis, PAs of last longest diameter over 21.75 mm were a significant prognostic factor for eventual treatment.

Conclusion

The initial tumor size of PAs was independently associated with the tumor growth. Six patients (11%) of conservatively managed PAs were likely to be treated eventually. PAs of last follow-up longest diameter over 21.75 mm were a significant prognostic factor for treatment. Further studies with a large series are required to determine treatment strategy.

Machine learning for detecting moyamoya disease in plain skull radiography using a convolutional neural network

Background

Recently, innovative attempts have been made to identify moyamoya disease (MMD) by focusing on the morphological differences in the head of MMD patients. Following the recent revolution in the development of deep learning (DL) algorithms, we designed this study to determine whether DL can distinguish MMD in plain skull radiograph images.

Methods

Three hundred forty-five skull images were collected as an MMD-labeled dataset from patients aged 18 to 50 years with definite MMD. As a control-labeled data set, 408 skull images of trauma patients were selected by age and sex matching. Skull images were partitioned into training and test datasets at a 7:3 ratio using permutation. A total of six convolution layers were designed and trained. The accuracy and area under the receiver operating characteristic (AUROC) curve were evaluated as classifier performance. To identify areas of attention, gradient-weighted class activation mapping was applied. External validation was performed with a new dataset from another hospital.

Findings

For the institutional test set, the classifier predicted the true label with 84·1% accuracy. Sensitivity and specificity were both 0·84. AUROC was 0·91. MMD was predicted by attention to the lower face in most cases. Overall accuracy for external validation data set was 75·9%.

Interpretation

DL can distinguish MMD cases within specific ages from controls in plain skull radiograph images with considerable accuracy and AUROC. The viscerocranium may play a role in MMD-related skull features.

Fund

This work was supported by grant no. 18-2018-029 from the Seoul National University Bundang Hospital Research Fund.

Pathogenesis of dorsal internal carotid artery wall aneurysms based on histopathologic examination and microscopic configuration

Blood blister-like aneurysms (BBAs) are an important cause of subarachnoid hemorrhage (SAH), but proper treatment is uncertain due to the poor prognosis of these aneurysms. The pathogenesis of BBAs remains unclear and few studies have reported on histological examinations of BBAs because it is difficult to obtain a specimen due to a high risk of intraoperative bleeding. In this report, BBAs were histopathologically examined in two patients who presented with SAH due to rupture of a BBA that was treated with surgical trapping and bypass surgery. BBA specimens including the adjacent internal carotid artery (ICA) walls were obtained intraoperatively. We suggest the pathogenesis of BBAs based on histopathologic examination and microscopic configuration.

Factors influencing the incidence and treatment of intracranial aneurysm and subarachnoid hemorrhage: time trends and socioeconomic disparities under an universal healthcare system

Background

Despite increasing usage of endovascular treatments for intracranial aneurysms, few research studies have been conducted on the incidence of unruptured aneurysm (UA) and subarachnoid hemorrhage (SAH), and could not show a decrease in the incidence of SAH. Moreover, research on socioeconomic disparities with respect to the diagnosis and treatment of UA and SAH is lacking.

Method

Trends in the incidences of newly detected UA and SAH and trends in the treatment modalities used were assessed from 2005 to 2015 using the nationwide database of the Korean National Health Insurance Service in South Korea. We also evaluated the influence of demographic characteristics including socioeconomic factors on the incidence and treatment of UA and SAH.

Result

The rates of newly detected UA and SAH were 28.3 and 13.7 per 100 000 of the general population, respectively, in 2015. The incidence of UA increased markedly over the 11-year study period, whereas that of SAH decreased slightly. UA patients were more likely to be female, older, employee-insured, and to have high incomes than SAH patients. In 2015, coiling was the most common treatment modality for both UA and SAH patients. Those who were female, employee-insured, or self-employed, with high income were likely to have a higher probability to be treated for UA and SAH.

Conclusion

The marked increase in the detection and treatment of UA might have contributed to the decreasing incidence of SAH, though levels of contribution depend on socioeconomic status despite universal medical insurance coverage.

Long-term outcomes of treatment for unruptured intracranial aneurysms in South Korea: clipping versus coiling

Background

The long-term outcomes of endovascular coiling and surgical clipping for the treatment of unruptured intracranial aneurysms are unclear.

Methods

We performed a nationwide retrospective cohort study using claims data from the Korean Health Insurance Review and Assessment Service on patients undergoing surgical clipping or endovascular coiling from 2008 to 2014. Inverse probability treatment weighting for average treatment effect on the treated and the multiple imputation method were used to balance covariates and handle missing values. The primary outcome was all-cause mortality at 7 years.

Results

We identified 26 411 patients of whom 11 777 underwent surgical clipping and 14 634 underwent endovascular coiling. After adjustment with the use of inverse probability treatment weighting for average treatment effect on the treated, all-cause mortality rates at 7 years were 3.8% in the endovascular coiling group and 3.6% in the surgical clipping group (HR 1.05; 95% CI 0.86 to 1.28; P=0.60, log-rank test). The adjusted probabilities of aneurysm rupture at 7 years were 0.9% after endovascular coiling and 0.7% after surgical clipping (HR 0.9; 95% CI 0.61 to 1.34; P=0.63, log-rank test). The probabilities of retreatment at 7 years after adjustment were 4.9% in the endovascular coiling group and 3.2% in the surgical clipping group (HR 1.52; 95% CI 1.28 to 1.81; P<0.001, log-rank test).

Conclusions

All-cause mortality at 7 years was similar between the elective surgical clipping and endovascular coiling groups in patients with unruptured aneurysms who had no history of subarachnoid hemorrhage due to aneurysm rupture.

Epidemiology of ruptured brain arteriovenous malformation: a National Cohort Study in Korea

OBJECTIVEBrain arteriovenous malformation (BAVM) is a rare cerebrovascular disease that causes intracranial hemorrhage. Although several reports have demonstrated the epidemiological features of BAVM in Western countries, no epidemiological investigations regarding BAVM have been reported in Korea. The authors aimed to investigate the national epidemiology of ruptured BAVM in a Korean population.METHODSThe authors used data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC). The original cohort included approximately 1 million individuals (2% of the Korean population) with 12-year claim data (2002-2013). To construct an initial cohort for investigation, the authors selected 1,016,820 registered individuals in 2005. Subjects with a history of cerebrovascular disease (code I6xx) and BAVM (Q282) between 2002 and 2004 were washed-out to identify incident cases. During the 9-year follow-up (2005-2013), the incidence of BAVM was calculated using the earliest date of diagnosis of ruptured or unruptured BAVM. Direct standardization was applied to the crude incidence. Mortality and disability were evaluated using registration data. Related diagnostic procedures were also analyzed.RESULTSA total of 8,802,696 person-years of observation were noted. During observation, 308 patients were diagnosed with a ruptured BAVM. The crude incidence of ruptured BAVM was 3.5 per 100,000 person-years. There was no sex difference in incidence. The mortality rate for patients with a ruptured BAVM 1 month after diagnosis was 12.7%. At 1-year and 5-year follow-up examinations, mortality rates were 17.2% and 22.1%, respectively. Severe disability-free survival rates of patients with ruptured AVMs were 75.3% and 69.8% at 1-year and 5-year follow-up, respectively.CONCLUSIONSThe standardized incidence of ruptured BAVMs was 3.6 per 100,000 person-years in Korea. Ruptured BAVMs resulted in high mortality and disability rates.

Surgical Treatment of Adult Moyamoya Disease

PURPOSE OF REVIEW

Moyamoya disease (MMD) is being increasingly diagnosed with the development of radiological surveillance technology and increased accessibility to medical care. Accordingly, there have been several recent reports on treatment outcomes in MMD. In this review, we summarize recent advances in surgical treatment and outcomes of adult MMD, while addressing related controversies.

RECENT FINDINGS

Recent studies suggest that revascularization surgery leads to significantly more favorable outcomes for stroke prevention, angiographic and hemodynamic changes, and clinical outcomes than does conservative treatment for adult patients with ischemic MMD. Moreover, direct revascularization methods should be considered as the first-line treatment over indirect methods, although the latter may be considered if a direct method is not possible. In cases of hemorrhagic MMD, several studies have demonstrated that surgical treatment is more effective than conservative treatment in preventing further hemorrhage. In addition to revascularization surgery, endovascular treatment is emerging as a breakthrough therapy for hemorrhagic MMD. Accumulating evidence regarding the surgical treatment of adult MMD suggests the benefit of revascularization over conservative management for both ischemic and hemorrhagic patients. However, the benefit of revascularization in asymptomatic adult MMD remains unclear.

Requirements for Cerebrovascular Surgery in Comprehensive Stroke Centers in South Korea

Objective

Cerebrovascular disease (CVD) was the third most common cause of death in South Korea in 2014. Evidence from abroad suggests that comprehensive stroke centers play an important role in improving the mortality rate of stroke. However, surgical treatment for CVD is currently slightly neglected by national policy, and there is still regional imbalance in this regard. For this reason, we conducted a survey on the necessity of, and the requirements for, establishing regional comprehensive cerebrovascular surgery centers (CCVSCs).

Methods

This investigation was performed using the questionnaire survey method. The questionnaire was consisted with two sections. The first concerned the respondent's opinion regarding the current status of demand and the regional imbalance of cerebrovascular surgery in South Korea. The second section asked about the requirements for establishing regional CCVSCs. We sent the questionnaire to 100 board members of the Korean Society of Cerebrovascular Surgeons.

Results

Most experts agreed that cerebrovascular surgery patients were concentrated in large hospitals in the capital area, and 83.6% of respondents agreed that it was necessary to alleviate the regional imbalance of cerebrovascular surgery. With regards to personnel, over 90% of respondents answered that at least two neuro-vascular surgeons and two neuro-interventionists are necessary to establish a CCVSC. Regarding facilities, almost all respondents stated that each CCVSC would require a neuro-intensive care unit and hybrid operating room. The survey asked the respondents about 13 specific neurovascular surgical procedures and whether they were necessary for a regional CCVSC. In the questions about the necessity of cerebrovascular surgical equipment, all seven pieces of equipment were considered essential by all respondents. A further five pieces of equipment were considered necessary on site: computed tomographic angiography, magnetic resonance angiography, conventional angiography, surgical microscope, and surgical navigation. Our results may provide a basis for future policy regarding treatment of cerebrovascular disease, including surgery.

Conclusion

Raising the comprehensiveness of treatment at a regional level would lower the national disease burden. Policies should be drafted regarding comprehensive treatment including surgery for cerebrovascular disease, and related support plans should be implemented.

Natural History and Risk Factor of Recurrent Hemorrhage in Hemorrhagic Adult Moyamoya Disease

BACKGROUND

Recurrent hemorrhage is a serious neurosurgical problem in adult moyamoya disease (MMD) patients.

OBJECTIVE

To find the natural history and risk factors of recurrent hemorrhage in cases of adult hemorrhagic MMD.

METHODS

One hundred seventy-six adult MMD patients presenting with hemorrhage were enrolled. Patients' medical records and radiological images were retrospectively reviewed. Clinical and radiological features of recurrent hemorrhage, and related risk factors were analyzed. Poor neurological outcome was defined as a score on the modified Rankin Scale of 4 to 6. The hemisphere in which the initial hemorrhage occurred was considered as the affected one. The mean follow-up duration was 83 months.

RESULTS

The overall estimated rate of recurrent hemorrhage was 16.9%/person (95% confidence interval, 11.3%-24.8%) at 5 years and 26.3%/person (95% confidence interval, 18.5%-36.4%) at 10 years after the initial episode of hemorrhage. The affected hemisphere showed a higher recurrent hemorrhagic rate (11.7% vs 8.3%/hemisphere at 5 years, P = .09) after conservative treatment. As a result of recurrent hemorrhages, the number of patients with poor neurological outcome increased (first episode: 13.8%, second: 37.5%, third: 40.0%, fourth: 100%). The presence of intraventricular hemorrhage ( P = .05, hazard ratio = 3.32) and bilateral MMD ( P = .05, hazard ratio = 4.15) had a marginal significance for recurrent hemorrhage. Eight ischemic strokes (4.5%) including 4 postoperative infarctions were identified, and all ischemic strokes were minor stroke.

CONCLUSION

During the follow-up period, recurrent hemorrhagic events continued to increase and deteriorated the patients' neurological conditions. The presence of intraventricular hemorrhage was a significant risk factor of recurrent hemorrhage.

Association of Hyperthyroidism and Thyroid Autoantibodies with Moyamoya Disease and Its Stroke Event: A Population-based Case-control Study and Meta-analysis

The aim of this study was to investigate the specific thyroid condition and thyroid autoantibodies in adult moyamoya disease (MMD) according to clinical presentation (ischemia vs. hemorrhage stroke). In addition, a meta-analysis was performed to reveal the association between adult MMD and elevated thyroid function, or autoantibodies. Prospectively collected data on 169 consecutive patients with MMD at a single institution were analyzed. Community-based controls matched for age and sex were selected for comparison. Penalized multinomial logistic regression analysis was used for factors affecting stroke. For meta-analysis, heterogeneity was evaluated by using the I² test. If I² < 50%, a fixed effect model was used. Fifty-four cases (32.0%) presented with ischemic stroke and 37 cases (21.9%) with hemorrhage stroke. Hyperthyroidism had a marginally increased risk of MMD with ischemic stroke with reference value of MMD without stroke [odds ratio (OR), 2.53; P = 0.055]. Anti-thyroperoxidase antibody (TPOAb) increased the risk of MMD presenting with ischemic stroke significantly (OR, 2.99; P = 0.020). A meta-analysis revealed that adult MMD was significantly associated with elevated autoantibodies (OR, 7.663; P = 0.002) and hyperthyroidism (OR, 10.936; P < 0.001). Elevated TPOAb and hyperthyroidism may play important roles in adult MMD with ischemic stroke. Studies focusing on targeted hyperthyroidism and thyroid autoantibodies are necessary in treating adult MMD patients in the future.

Long-Term Outcomes of Patients with Stent Tips Embedded into Internal Carotid Artery Branches during Aneurysm Coiling

BACKGROUND AND PURPOSE

During stent-assisted coiling of ICA aneurysms, stent tips are sometimes unintentionally embedded into ICA branches. Stent tips can be visualized because they have radiopaque markers. Concerns regarding stent tip misplacement include risks of artery perforation and occlusion. The aim of this study was to evaluate the long-term outcomes of ICA branches with embedded stent tips.

MATERIALS AND METHODS

ICA branches with embedded stent tips were identified among 35 patients with unruptured ICA aneurysms treated with stent-assisted coiling between November 2003 and November 2014. Patient clinical and angiographic outcomes associated with the embedded stent tip were analyzed.

RESULTS

Most of the 35 studied aneurysms were paraclinoid ICA aneurysms (n = 30). The most commonly involved ICA branch was the posterior communicating artery (26 patients, 74.3%), followed by the anterior choroidal artery (8 patients, 22.9%) and ophthalmic artery (1 patient, 2.9%). During the follow-up period (38.6 ± 17.9 months), no new neurologic deficits developed. Neither hemorrhagic nor thromboembolic events occurred. Angiography was performed during the final follow-up evaluation at a mean of 32.7 ± 18.0 months, and all ICA branches with embedded stent tips showed patent blood flow without severe luminal narrowing.

CONCLUSIONS

In our experience, placement of a stent tip into ICA branches during stent-assisted coiling was not associated with any major adverse events.

Korean Clinical Practice Guidelines for Aneurysmal Subarachnoid Hemorrhage

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, worldwide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

Radiologic Measurement of Brain Swelling in Patients with Large Hemispheric Infarctions During Targeted Temperature Management

Brain herniation is most often the result of severe brain swelling and can rapidly lead to death or brain death. We retrospectively identified radiologic indicators to evaluate the effects of targeted temperature management (TTM) on the extent of cerebral edema and determine the cutoff values that best predict TTM outcomes in patients with large hemispheric infarction. We retrospectively reviewed brain computed tomography (CT) scans of 21 patients with large hemispheric infarctions, who were treated with TTM. We excluded 4 patients whose CT scans were inadequate for evaluation, which left 17 patients. We divided the patients into success and failure groups. TTM failure was defined as death or the need for decompressive hemicraniectomy (DHC) after TTM. Infarction size was measured as the total restricted area in diffusion-weighted imaging that was performed on admission. CT scans were obtained on the first and second days after TTM initiation and then every 2 days. We measured septum pellucidum shifts (SPS) and pineal gland shifts (PGS) on CT scans. The median time from symptom onset to TTM initiation was 14.5 hours. Ten patients were successfully treated with TTM, six patients died, and one patient underwent a DHC. Initial infarction sizes were not significantly different between the success and failure groups (p = 0.529), but the SPS and PGS at 36-72 hours after TTM initiation were (mean SPS: 5.0 vs. 14.9 mm, p = 0.001; mean PGS: 2.3 vs. 7.9 mm, p = 0.001). The sensitivity and negative predictive value for TTM failure caused by cerebral edema (SPS ≥9.25 mm and PGS ≥3.70 mm) at 36-72 hours after TTM initiation were both 100%. The SPS and PGS on CT scans taken 36-72 hours after TTM initiation may help to estimate the effect of TTM on cerebral edema and guide further treatment.

Pruritic arthropod bite-like papules in T-cell large granular lymphocytic leukaemia and chronic myelomonocytic leukaemia

T-cell large granular lymphocytic leukaemia (T-LGLL) is a clinically indolent mature T-cell neoplasm characterized by a monoclonal population of CD3+ CD8+ cytotoxic T cells, which usually presents as neutropenia, anaemia and thrombocytopenia. Chronic myelomonocytic leukaemia (CMML) is a clonal haematopoietic disorder with features of both a myeloproliferative neoplasm and myelodysplastic syndrome (MDS). Patients with CMML exhibit a persistent peripheral blood monocytosis in addition to myelodysplastic features. Because of the rarity of T-LGLL, its cutaneous manifestations are poorly documented, but include vasculitis, vasculopathy, persistent ulcerations, generalized pruritus and disseminated granuloma annulare. Various types of skin lesions have been observed in patients with CMML and reportedly occur in approximately 10% of cases. We report the extraordinary case of a patient with MDS who developed T-LGLL, and subsequently the MDS progressed to CMML. The patient then developed diffuse arthropod bite-like papules and intractable pruritus.

Successful retinal blood flow augmentation after extracranial-intracranial bypass

A 61-year-old woman visited us with recent onset right-side weakness. Magnetic resonance imaging showed ischemic changes at the left internal border zone due to occlusive disease affecting the left proximal internal carotid artery. Prompt oral dual antiplatelet therapy and intravenous fluid were administered with subsequent induced hypertension and without reperfusion therapy. Although the hemiparesis was improved, she complained of a new-onset transient left-side monocular visual loss. Fluorescein angiography confirmed delayed perfusion in the left eye. We performed extracranial-intracranial bypass for flow augmentation. After bypass, the amaurosis fugax resolved. Follow-up retinal fluorescein angiography also showed improved retinal perfusion.

Genetic Risk Assessment of Elastin Gene Polymorphisms with Intracranial Aneurysm in Koreans

Elastin encoded by elastin gene (ELN) is a crucial extracellular matrix protein responsible for arterial resilience. The objective of this study was to identify single nucleotide polymorphisms (SNPs) of ELN gene susceptible to intracranial aneurysm (IA) in Korean population. Two SNPs of ELN gene, rs2071307 (Gly422Ser) and rs2856728 (intron), were genotyped in 90 patients with IA and 90 age and frequency matched controls. Fisher’s exact test was conducted to evaluate allelic association with IA. Of the two SNPs in ELN gene, T allele of rs2856728 (intron) showed statistically significant association with increased development of IA (odds ratio [OR]: 2.34, 95% confidence interval [CI]: 1.44–3.81, P = 7.6 × 10⁻⁴). However, G allele of rs2071307 (Gly422Ser) had no significant association with the development of IA (OR: 1.27, 95% CI: 1.44–3.81, P = 0.607). Interestingly, the odds of having rs2856728 variant was approximately 2-fold higher in males than that in females (OR: 3.46 vs. 1.88, P < 0.05). However, none of SNPs showed difference between single and multiple IA in this study. This preliminary study implies that the rs2856728 variant in ELN gene polymorphisms might play crucial roles in the development and pathogenesis of IA in Korean population.

Middle Meningeal Artery Embolization for Chronic Subdural Hematoma

Purpose To evaluate the effect of middle meningeal artery (MMA) embolization on chronic subdural hematoma (CSDH) and compare the treatment outcomes of MMA embolization and conventional treatment. Materials and Methods All consecutive patients 20 years or older with CSDH were assessed for eligibility. CSDHs with a focal location, a thickness of 10 mm or less, no mass effect, or underlying conditions were excluded. Seventy-two prospectively enrolled patients with CSDH underwent MMA embolization (embolization group; as the sole treatment in 27 [37.5%] asymptomatic patients and with additional hematoma removal for symptom relief in 45 [62.5%] symptomatic patients). For comparison, 469 patients who underwent conventional treatment were included as a historical control group (conventional treatment group; close, nonsurgical follow-up in 67 [14.3%] and hematoma removal in 402 [85.7%] patients). Primary outcome was treatment failure defined as a composite of incomplete hematoma resolution (remaining or reaccumulated hematoma with thickness > 10 mm) or surgical rescue (hematoma removal for relief of symptoms that developed with continuous growth of initial or reaccumulated hematoma). Secondary outcomes included surgical rescue as a component of the primary outcome and treatment-related complication for safety measure. Six-month outcomes were compared between the study groups with logistic regression analysis. Results Spontaneous hematoma resolution was achieved in all of 27 asymptomatic patients undergoing embolization without direct hematoma removal. Hematoma reaccumulation occurred in one (2.2%) of 45 symptomatic patients receiving embolization with additional hematoma removal. Treatment failure rate in the embolization group was lower than in the conventional treatment group (one of 72 patients [1.4%] vs 129 of 469 patients [27.5%], respectively; adjusted odds ratio [OR], 0.056; 95% confidence interval [CI]: 0.011, 0.286; P = .001). Surgical rescue was less frequent in the embolization group (one of 72 patients [1.4%] vs 88 of 469 patients [18.8%]; adjusted OR, 0.094; 95% CI: 0.018, 0.488; P = .005). Treatment-related complication rate was not different between the two groups (0 of 72 patients vs 20 of 469 patients [4.3%]; adjusted OR, 0.145; 95% CI: 0.009, 2.469; P = .182). Conclusion MMA embolization has a positive therapeutic effect on CSDH and is more effective than conventional treatment. ^© RSNA, 2017.

The Role of Adjuvant Treatment in Patients with High-Grade Meningioma

Objective

To investigate the efficacy of adjuvant treatment in patients with high-grade meningioma.

Methods

A retrospective analysis was performed for patients with high-grade meningioma, World Health Organization grade 2 or 3, in a single center between 2003 and 2014. The patients were reviewed according to age at diagnosis, sex, the location of meningioma, degree of tumor resection, histological features, and type of adjuvant treatment. These factors were analyzed by Firth logistic regression analyses.

Results

Fifty-three patients with high-grade meningioma were enrolled. Thirty-four patients received adjuvant treatment; conventional radiotherapy or radiosurgery. Clinical follow-up ranged from 13–113 months with a median follow-up of 35.5 months. Gross total removal (GTR), Simpson grade 1 or 2, was achieved in 29 patients and, among them, 13 patients received adjuvant treatment. In the other 24 patients with non-GTR, conventional adjuvant radiotherapy and radiosurgery were performed in 11 and 10 patients, respectively. The other 3 patients did not receive any adjuvant treatment. Radiation-related complications did not occur. Of the 53 patients, 19 patients had suffered from recurrence. The recurrence rate in the adjuvant treatment group was 23.5% (8 out of 34). On the other hand, the rate for the non-adjuvant treatment group was 57.9% (11 out of 19) (odds ratio [OR]=0.208, p=0.017). In the GTR group, the recurrence rate was 7.5% (1 out of 13) for patients with adjuvant treatment and 50% (8 out of 16) for patients without adjuvant treatment (OR=0.121, p=0.04).

Conclusion

Adjuvant treatment appears to be safe and effective, and could lead to a lower recurrence rate in high-grade meningioma, regardless of the extent of removal. Our results might be used as a reference for making decisions when planning adjuvant treatments for patients with high-grade meningioma after surgery.

Bypass Surgery for Complex Intracranial Aneurysms: 15 Years of Experience at a Single Institution and Review of Pertinent Literature

BACKGROUND

Bypass surgery is a treatment option for complex intracranial aneurysms.

OBJECTIVE

To determine the utility of bypass surgery for the treatment of complex intracranial aneurysms and to review the literature on this topic.

METHODS

Sixty-two patients were included in this retrospective study. Unruptured aneurysms were dominant (80.6%), and the internal carotid artery was the most common location of the aneurysm (56.4%), followed by the middle cerebral artery (21.0%). The mean maximal diameter of the aneurysms was 20.5 ± 11.4 mm. The clinical and angiographic states were evaluated preoperatively, immediately after surgery (within 3 days) and at the last follow-up. The mean angiographic and clinical follow-up duration was 34.2 ± 38.9 and 46.5 ± 42.5 months, respectively.

RESULTS

Sixty-one patients (98.3%) underwent extracranial–intracranial bypass, and 1 underwent intracranial–intracranial bypass. At the last follow-up angiography, 58 aneurysms (93.5%) were completely obliterated and 4 were incompletely obliterated, with a graft patency of 90.3%. Surgical mortality was 0 and permanent morbidity was 8.1%. A good clinical outcome (Karnofsky Performance Scale ≥ 70 and modified Rankin Scale score ≤ 2) was achieved in 91.9% of patients (n = 57).

CONCLUSION

With a proper selection of bypass type, bypass-associated treatment can be a good alternative for patients with complex intracranial aneurysms when conventional microsurgical clipping or endovascular intervention is not feasible.

Erratum: Risk Factor Analysis for the Recurrence of Chronic Subdural Hematoma: A Review of 368 Consecutive Surgical Cases

[This corrects the article on p. 63 in vol. 11, PMID: 27169067.].

Meta-analysis of the surgical outcomes of symptomatic moyamoya disease in adults

OBJECTIVE The purpose of this study was to evaluate treatment outcomes of future stroke prevention, perioperative complications, and angiographic revascularization in adults with symptomatic moyamoya disease (MMD) according to treatment modalities and surgical techniques. METHODS A systemic literature review was performed based on searches of the PubMed, Embase, and Cochrane Central databases. A fixed-effects model was used in cases of heterogeneity less than 50%. Publication bias was determined by Begg's funnel plot, Egger's test of the intercept, and the Begg and Mazumdar rank correlation test. RESULTS Eleven articles were included in the meta-analysis. Bypass surgery significantly decreased the future stroke events compared with conservative treatments in adult MMD (odds ratio [OR] 0.301, p < 0.001). Direct bypass showed better future stroke prevention than indirect bypass (OR 0.494, p = 0.028). There was no meaningful difference in perioperative complications between direct and indirect bypass (OR 0.665, p = 0.176). Direct bypass was associated with better angiographic outcomes than indirect bypass (OR 6.832, p < 0.001). CONCLUSIONS Bypass surgery can be effective in preventing future stoke events in adults with MMD. Direct bypass seems to provide better risk reduction with respect to stroke than indirect bypass in these patients.