1
|
Araki Y, Yokoyama K, Uda K, Kanamori F, Takayanagi K, Ishii K, Nishihori M, Goto S, Tsukada T, Takeuchi K, Tanahashi K, Nagata Y, Nishimura Y, Tanei T, Nagashima Y, Muraoka S, Izumi T, Seki Y, Saito R. The Potential Role of Preoperative Posterior Cerebral Artery Involvement in Predicting Postoperative Transient Neurological Deficits and Ischemic Stroke After Indirect Revascularization in Patients With Moyamoya Disease. World Neurosurg 2024; 187:e610-e619. [PMID: 38677649 DOI: 10.1016/j.wneu.2024.04.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 04/20/2024] [Indexed: 04/29/2024]
Abstract
OBJECTIVE Transient neurological deficits (TNDs) are known to develop after direct bypass for Moyamoya disease and may be risk factors for subsequent stroke. However, the factors involved in the development of TNDs and stroke after indirect revascularization alone, including their association with subsequent stroke, remain unclear. The purpose of this study was to investigate this issue. METHODS The subjects of the study were 30 patients with Moyamoya disease who underwent a total of 40 indirect revascularization procedures at our institution. Clinical and radiological data were collected retrospectively. To examine factors associated with the development of postoperative TND/stroke/asymptomatic disease, the clinical characteristics of each group were statistically compared. RESULTS The mean age at surgery was 7 years (range 1-63). TNDs developed after surgery in 9 out of 40 patients (22.5%). Stroke in the acute postoperative period occurred in 3 patients (7.5%), all of whom experienced cerebral infarctions. Demographic data and preoperative clinical information were not different between the groups. However, posterior cerebral artery involvement on preoperative imaging was significantly associated with the development of TNDs and stroke (P = 0.006). Furthermore, postoperative stroke was associated with unfavorable outcomes (P = 0.025). CONCLUSIONS Posterior cerebral artery involvement is significantly associated with the occurrence of TNDs. In contrast, TNDs after indirect revascularization have little relationship with the subsequent development of stroke. TNDs usually resolve without new strokes, and a better understanding of this particular pathology could help establish an optimal treatment regimen.
Collapse
Affiliation(s)
- Yoshio Araki
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital, Nagoya, Aichi, Japan.
| | - Kinya Yokoyama
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kenji Uda
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; Department of Neurosurgery, Nagoya Ekisaikai Hospital, Nagoya, Aichi, Japan
| | - Fumiaki Kanamori
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kai Takayanagi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kazuki Ishii
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Masahiro Nishihori
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Shunsaku Goto
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Tetsuya Tsukada
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital, Nagoya, Aichi, Japan
| | - Kazuhito Takeuchi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kuniaki Tanahashi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yuichi Nagata
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yusuke Nishimura
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Takafumi Tanei
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yoshitaka Nagashima
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Shinsuke Muraoka
- Department of Neurosurgery, Kariya Toyota General Hospital, Kariya, Aichi, Japan
| | - Takashi Izumi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yukio Seki
- Department of Neurosurgery, Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital, Nagoya, Aichi, Japan
| | - Ryuta Saito
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| |
Collapse
|
2
|
Lei Y, Zhang X, Ni W, Gao C, Li Y, Yang H, Gao X, Xia D, Zhang X, Osipowicz K, Doyen S, Sughrue ME, Gu Y, Mao Y. Application of individual brain connectome in chronic ischemia: mapping symptoms before and after reperfusion. MedComm (Beijing) 2024; 5:e585. [PMID: 38832213 PMCID: PMC11144839 DOI: 10.1002/mco2.585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 04/06/2024] [Accepted: 05/01/2024] [Indexed: 06/05/2024] Open
Abstract
How brain functions in the distorted ischemic state before and after reperfusion is unclear. It is also uncertain whether there are any indicators within ischemic brain that could predict surgical outcomes. To alleviate these issues, we applied individual brain connectome in chronic steno-occlusive vasculopathy (CSOV) to map both ischemic symptoms and their postbypass changes. A total of 499 bypasses in 455 CSOV patients were collected and followed up for 47.8 ± 20.5 months. Using multimodal parcellation with connectivity-based and pathological distortion-independent approach, areal MR features of brain connectome were generated with three measurements of functional connectivity (FC), structural connectivity, and PageRank centrality at the single-subject level. Thirty-three machine-learning models were then trained with clinical and areal MR features to obtain acceptable classifiers for both ischemic symptoms and their postbypass changes, among which, 11 were deemed acceptable (AUC > 0.7). Notably, the FC feature-based model for long-term neurological outcomes performed very well (AUC > 0.8). Finally, a Shapley additive explanations plot was adopted to extract important individual features in acceptable models to generate "fingerprints" of brain connectome. This study not only establishes brain connectomic fingerprint databases for brain ischemia with distortion, but also provides informative insights for how brain functions before and after reperfusion.
Collapse
|
3
|
Sun LR, Jordan LC, Smith ER, Aldana PR, Kirschen MP, Guilliams K, Gupta N, Steinberg GK, Fox C, Harrar DB, Lee S, Chung MG, Dirks P, Dlamini N, Maher CO, Lehman LL, Hong SJ, Strahle JM, Pineda JA, Beslow LA, Rasmussen L, Mailo J, Piatt J, Lang SS, Adelson PD, Dewan MC, Mineyko A, McClugage S, Vadivelu S, Dowling MM, Hersh DS. Pediatric Moyamoya Revascularization Perioperative Care: A Modified Delphi Study. Neurocrit Care 2024; 40:587-602. [PMID: 37470933 PMCID: PMC11023720 DOI: 10.1007/s12028-023-01788-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 06/20/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities. METHODS Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement. RESULTS Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery. CONCLUSIONS In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.
Collapse
Affiliation(s)
- Lisa R Sun
- Division of Cerebrovascular Neurology, Division of Pediatric Neurology, The Johns Hopkins School of Medicine, Baltimore, MD, USA.
| | - Lori C Jordan
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Edward R Smith
- Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA
| | - Philipp R Aldana
- Division of Pediatric Neurosurgery, University of Florida College of Medicine, Section of Neurosurgery, Wolfson Children's Hospital, Jacksonville, FL, USA
| | - Matthew P Kirschen
- Departments of Anesthesiology and Critical Care Medicine, Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Kristin Guilliams
- Departments of Neurology, Pediatrics, and Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nalin Gupta
- Departments of Neurological Surgery and Pediatrics, University of California, San Francisco, CA, USA
| | - Gary K Steinberg
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Christine Fox
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Dana B Harrar
- Division of Neurology, Children's National Hospital, George Washington University School of Medicine, Washington, DC, USA
| | - Sarah Lee
- Division of Child Neurology, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Melissa G Chung
- Department of Pediatrics, Divisions of Pediatric Neurology and Critical Care Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Peter Dirks
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, Canada
| | - Nomazulu Dlamini
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
| | - Cormac O Maher
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Laura L Lehman
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Sue J Hong
- Department of Pediatrics, Divisions of Critical Care and Child Neurology, Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Jennifer M Strahle
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Jose A Pineda
- Department of Critical Care, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - Lauren A Beslow
- Division of Neurology, Children's Hospital of Philadelphia, Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Lindsey Rasmussen
- Department of Critical Care, Stanford University School of Medicine, Stanford, CA, USA
| | - Janette Mailo
- Division of Pediatric Neurology, Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - Joseph Piatt
- Division of Neurosurgery, Nemours Children's Hospital Delaware, Wilmington, DE, USA
| | - Shih-Shan Lang
- Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - P David Adelson
- Department of Neurosurgery, WVU Medicine and WVU Medicine Children's Hospital, Morgantown, WV, USA
| | - Michael C Dewan
- Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Aleksandra Mineyko
- Department of Pediatrics, Section on Neurology, University of Calgary, Calgary, AB, Canada
| | - Samuel McClugage
- Department of Neurosurgery, Texas Children's Hospital, Houston, TX, USA
| | - Sudhakar Vadivelu
- Division of Pediatric Neurosurgery and Interventional Neuroradiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Michael M Dowling
- Departments of Pediatrics and Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - David S Hersh
- Division of Neurosurgery, Connecticut Children's, Hartford, CT, USA
| |
Collapse
|
4
|
Qian MP, Dong MR, Han MM, Li J, Kang F. ABO blood types may affect transient neurological events after surgical revascularization in patients with moyamoya disease: a retrospective single center study. BMC Anesthesiol 2023; 23:419. [PMID: 38114904 PMCID: PMC10729420 DOI: 10.1186/s12871-023-02385-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/14/2023] [Indexed: 12/21/2023] Open
Abstract
BACKGROUND Moyamoya disease (MMD) is a cerebrovascular disease with unknown cause. Patients with MMD disease usually experience transient neurological events (TNEs) after revascularization surgery. This retrospective single-center study was aimed to explore the risk factors of postoperative TNEs after surgical revascularization in patients with MMD. METHODS We selected 324 patients who underwent surgical revascularization between January 2017 and September 2022 in our center. The perioperative characteristics of the patients were recorded and the outcome was TNEs after surgery. An analysis of risk factors contributing to postoperative TNEs by using logistic regression model. RESULTS Three hundred twelve patients were enrolled, and the incidence of postoperative TNEs was 34% in our study. Males were more likely to suffer from postoperative TNEs (OR = 2.344, p = 0.002). Preoperative ischemic presentation (OR = 1.849, p = 0.048) and intraoperative hypotension (OR = 2.332, p = 0.002) were associated with postoperative TNEs. Compared to patients with blood type O, patients with blood type A (OR = 2.325, p = 0.028), B (OR = 2.239, p = 0.027) and AB (OR = 2.938, p = 0.019) had a significantly higher incidence of postoperative TNEs. A risk prediction model for postoperative TNEs was established, and the established risk prediction area under the receiver operating characteristic curve (ROC) of the model was 0.741. CONCLUSIONS Males, preoperative ischemic presentation and intraoperative hypotension were associated with postoperative TNEs. We also found a possible link between postoperative TNEs and ABO blood types after surgical revascularization for moyamoya patients.
Collapse
Affiliation(s)
- Mei-Ping Qian
- Department of Anesthesiology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230036, Anhui, China
| | - Mei-Rong Dong
- Department of Anesthesiology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230036, Anhui, China
| | - Ming-Ming Han
- Department of Anesthesiology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230036, Anhui, China
| | - Juan Li
- Department of Anesthesiology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230036, Anhui, China
| | - Fang Kang
- Department of Anesthesiology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230036, Anhui, China.
| |
Collapse
|
5
|
Guo Z, Yan Z, Qu F, Cheng D, Wang C, Feng Y. The value of indocyanine green-FLOW800 in microvasculature for predicting cerebral hyperperfusion syndrome in moyamoya disease patients. Sci Rep 2023; 13:18352. [PMID: 37884669 PMCID: PMC10603131 DOI: 10.1038/s41598-023-45676-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023] Open
Abstract
Among the notable complications of direct hemodynamic reconstruction for moyamoya disease (MMD) is cerebral hyperperfusion syndrome (CHS). In this study, we evaluated hemodynamic changes in small regional microvasculature (SRMV) around the anastomosis site by using indocyanine green (ICG)-FLOW800 video angiography and verified that it better predicted the onset of CHS. Intraoperative ICG-FLOW800 analysis was performed on 31 patients (36 cerebral hemispheres) with MMD who underwent superficial temporal artery-middle cerebral artery (MCA) bypass grafting at our institution. The regions of interest were established in the SRMV and thicker MCA around the anastomosis. Calculations were made for half-peak to time (TTP1/2), cerebral blood volume (CBV), and cerebral blood flow (CBF). According to the presence or absence of CHS after surgery, CHS and non-CHS groups of patients were separated. The results showed that ΔCBV and ΔCBF were substantially greater in SRMV than in MCA (p < 0.001). Compared with the non-CHS group, ΔCBF and ΔCBV of SRMV and MCA were considerably greater in the CHS group (p < 0.001). ΔCBF and ΔCBV on the ROC curve for both SRMV and MCA had high sensitivity and specificity (SRMV: ΔCBF, AUC = 0.8586; ΔCBV, AUC = 0.8158. MCA: ΔCBF, AUC = 0.7993; ΔCBV, AUC = 0.8684). ICG-FLOW800 video angiography verified the differential hemodynamic changes in the peri-anastomotic MCA and SRMV before and after bypass surgery in patients with MMD.
Collapse
Affiliation(s)
- Zhongxiang Guo
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Jiangsu Road No. 16, Qingdao, 266003, Shandong Province, China
| | - Zhaohui Yan
- Department of Neurosurgery, Haiyang People's Hospital, Haiyang Road No. 37, Haiyang, 265199, Shandong Province, China
| | - Fan Qu
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Jiangsu Road No. 16, Qingdao, 266003, Shandong Province, China
| | - Dekui Cheng
- Department of Neurosurgery, Liaocheng People's Hospital, Dongchang West Road No. 67, Liaocheng, 25200, Shandong Province, China
| | - Chao Wang
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Jiangsu Road No. 16, Qingdao, 266003, Shandong Province, China
| | - Yugong Feng
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Jiangsu Road No. 16, Qingdao, 266003, Shandong Province, China.
| |
Collapse
|
6
|
Gao F, Cong J, Duan Y, Zhao W, Zhu Z, Zheng Y, Jin L, Ji M, Li M. Screening of postoperative cerebral hyperperfusion syndrome in moyamoya disease: a three-dimensional pulsed arterial-spin labeling magnetic resonance imaging approach. Front Neurosci 2023; 17:1274038. [PMID: 37928741 PMCID: PMC10620603 DOI: 10.3389/fnins.2023.1274038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023] Open
Abstract
Introduction Moyamoya disease (MMD) is associated with a risk of postoperative cerebral hyperperfusion syndrome (CHS) after revascularization surgery. This study aimed to explore the feasibility of using three-dimensional pulsed arterial spin labeling (3D PASL) and phase contrast (PC) magnetic resonance imaging (MRI) for predicting CHS occurrence in patients with MMD before revascularization surgery. Methods Overall, 191 adult patients (207 hemispheres) with MMD who underwent combined revascularization surgery were included in this study. Preoperative 3D PASL-MRI and PC-MRI were performed before surgery. The PASL-MRI data were analyzed using SPM12. Patient clinical information, average flow, and preoperative cerebral blood flow (CBF) were compared between the non-CHS and CHS groups. Results Among the patients, 45 (21.74%) developed CHS after revascularization surgery. No significant differences were noted in age, sex, clinical symptoms, hypertension, diabetes, surgical side, or history of revascularization surgery between the non-CHS and CHS groups. However, the average flow in the superficial temporal artery was significantly lower in the CHS group than in the non-CHS group (p < 0.05). Furthermore, 11 clusters of preoperative CBF values were significantly greater in the CHS group than in the non-CHS group [p < 0.05, false discovery rate (FDR) corrected]. A significant correlation was also observed between the preoperative time-to-flight MR angiography (MRA) scores and CBF values in patients with MMD (p < 0.05). Conclusion Compare patients with lower preoperative CBF and higher preoperative average flow in the STA, patients with higher preoperative CBF and lower preoperative average flow in the STA are more likely to develop postoperative CHS Preoperative PASL-MRI and PC-MRI examinations may help to screen patients at high risk of developing CHS after revascularization surgery.
Collapse
Affiliation(s)
- Feng Gao
- Department of Radiology, Huadong Hospital Fudan University, Shanghai, China
| | - Jianhua Cong
- Department of Medical Centre, Huadong Hospital Fudan University, Shanghai, China
| | - Yu Duan
- Department of Neurosurgery, Huadong Hospital Fudan University, Shanghai, China
| | - Wei Zhao
- Department of Radiology, Second Xiangya Hospital, Central South University, Changsha, China
| | - Zhenfang Zhu
- Department of Radiology, Huadong Hospital Fudan University, Shanghai, China
| | - Yu Zheng
- Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, China
| | - Liang Jin
- Department of Radiology, Huadong Hospital Fudan University, Shanghai, China
| | - Ming Ji
- Department of Radiology, Huadong Hospital Fudan University, Shanghai, China
| | - Ming Li
- Department of Radiology, Huadong Hospital Fudan University, Shanghai, China
| |
Collapse
|
7
|
Mitchell DL, Shlobin NA, LoPresti MA, Scoville JP, Winterhalter E, Lam S. Post-Surgical Cognitive Outcomes of Moyamoya Disease: A Systematic Review. World Neurosurg 2023; 178:181-190.e1. [PMID: 37506837 DOI: 10.1016/j.wneu.2023.07.099] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023]
Abstract
BACKGROUND Moyamoya disease (MMD) is an occlusive arteriopathy leading to stroke. Progressive if left untreated, revascularization surgery has become the mainstay of treatment. Although clinical and radiographic outcomes of MMD after intervention are well-characterized, cognitive outcomes in pediatric patients remain unclear. We aimed to examine postoperative cognitive outcomes in children with MMD, examine factors associated with cognitive changes after intervention, and define the effect of revascularization surgery on cognitive outcomes. METHODS A systematic review was conducted following PRISMA guidelines searching PubMed, Embase, and Scopus databases. Articles met inclusion criteria if they studied pediatric patients undergoing revascularization surgery for MMD and examined cognitive outcomes either qualitatively or quantitatively. All data extracted from included articles was examined descriptively. RESULTS Of 1091 resultant articles, 12 articles containing 446 patients were included. Surgery was associated with maintained or improved full scale intellectual quotient (IQ), performance IQ, perceptual IQ, memory quotient and verbal memory. However, 70% of patients had impaired cognitive function, with associated poor school performance. Improvements in cognition were associated with increased cerebral blood flow, particularly to the middle cerebral artery, due to the development of collaterals. Female sex, shorter duration from symptom onset to surgery, and surgery after age 7 were predictive of cognitive improvement. Completed ischemic stroke prior to surgery was associated with poorer cognitive outcomes. CONCLUSIONS Although children with MMD have improved cognitive outcomes following revascularization overall, a distinct subset experience cognitive impairment. Consideration of patient-specific and treatment-related factors is important to enable proper risk stratification and inform management approaches.
Collapse
Affiliation(s)
- Devon L Mitchell
- Division of Pediatric Neurosurgery, Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital, Chicago, Illinois, USA
| | - Nathan A Shlobin
- Division of Pediatric Neurosurgery, Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital, Chicago, Illinois, USA
| | - Melissa A LoPresti
- Division of Pediatric Neurosurgery, Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital, Chicago, Illinois, USA
| | - Jonathan P Scoville
- Division of Pediatric Neurosurgery, Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital, Chicago, Illinois, USA
| | - Emily Winterhalter
- Division of Pediatric Neurosurgery, Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital, Chicago, Illinois, USA
| | - Sandi Lam
- Division of Pediatric Neurosurgery, Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital, Chicago, Illinois, USA.
| |
Collapse
|
8
|
Dorschel KB, Wanebo JE. Physiological and pathophysiological mechanisms of the molecular and cellular biology of angiogenesis and inflammation in moyamoya angiopathy and related vascular diseases. Front Neurol 2023; 14:661611. [PMID: 37273690 PMCID: PMC10236939 DOI: 10.3389/fneur.2023.661611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 01/16/2023] [Indexed: 06/06/2023] Open
Abstract
Rationale The etiology and pathophysiological mechanisms of moyamoya angiopathy (MMA) remain largely unknown. MMA is a progressive, occlusive cerebrovascular disorder characterized by recurrent ischemic and hemorrhagic strokes; with compensatory formation of an abnormal network of perforating blood vessels that creates a collateral circulation; and by aberrant angiogenesis at the base of the brain. Imbalance of angiogenic and vasculogenic mechanisms has been proposed as a potential cause of MMA. Moyamoya vessels suggest that aberrant angiogenic, arteriogenic, and vasculogenic processes may be involved in the pathophysiology of MMA. Circulating endothelial progenitor cells have been hypothesized to contribute to vascular remodeling in MMA. MMA is associated with increased expression of angiogenic factors and proinflammatory molecules. Systemic inflammation may be related to MMA pathogenesis. Objective This literature review describes the molecular mechanisms associated with cerebrovascular dysfunction, aberrant angiogenesis, and inflammation in MMA and related cerebrovascular diseases along with treatment strategies and future research perspectives. Methods and results References were identified through a systematic computerized search of the medical literature from January 1, 1983, through July 29, 2022, using the PubMed, EMBASE, BIOSIS Previews, CNKI, ISI web of science, and Medline databases and various combinations of the keywords "moyamoya," "angiogenesis," "anastomotic network," "molecular mechanism," "physiology," "pathophysiology," "pathogenesis," "biomarker," "genetics," "signaling pathway," "blood-brain barrier," "endothelial progenitor cells," "endothelial function," "inflammation," "intracranial hemorrhage," and "stroke." Relevant articles and supplemental basic science articles almost exclusively published in English were included. Review of the reference lists of relevant publications for additional sources resulted in 350 publications which met the study inclusion criteria. Detection of growth factors, chemokines, and cytokines in MMA patients suggests the hypothesis of aberrant angiogenesis being involved in MMA pathogenesis. It remains to be ascertained whether these findings are consequences of MMA or are etiological factors of MMA. Conclusions MMA is a heterogeneous disorder, comprising various genotypes and phenotypes, with a complex pathophysiology. Additional research may advance our understanding of the pathophysiology involved in aberrant angiogenesis, arterial stenosis, and the formation of moyamoya collaterals and anastomotic networks. Future research will benefit from researching molecular pathophysiologic mechanisms and the correlation of clinical and basic research results.
Collapse
Affiliation(s)
- Kirsten B. Dorschel
- Medical Faculty, Heidelberg University Medical School, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - John E. Wanebo
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, United States
- Department of Neuroscience, HonorHealth Research Institute, Scottsdale, AZ, United States
| |
Collapse
|
9
|
Chiba K, Aihara Y, Fukui A, Yamaguchi K, Kawashima A, Okada Y, Kawamata T. Transient neurological events in childhood moyamoya disease. J Neurosurg Pediatr 2023; 31:78-86. [PMID: 36334284 DOI: 10.3171/2022.9.peds22166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Patients sometimes experience transient neurological events (TNEs) during the early postoperative period after revascularization surgery for childhood moyamoya disease. The clinical background and pathophysiology of TNEs remain unclear. This study aimed to evaluate the incidence rate of TNEs and discuss the factors associated with pediatric moyamoya disease. METHODS The authors retrospectively reviewed 110 cerebral hemispheres of 61 pediatric patients younger than 15 years who were treated from 2011 to 2020. All children underwent either simple double-direct or combined revascularization surgery. Of these 61 patients, 52 underwent bilateral surgery and 9 underwent unilateral surgery. The authors calculated the incidence of TNEs in accordance with a previously reported TNE definition. Cerebral blood flow (CBF) was evaluated in all eligible cases with xenon CT immediately after revascularization surgery. RESULTS The incidence rate of TNEs in patients with childhood moyamoya disease was 26.4%. TNEs occurred after an average (range) of 6.26 (2-12) days postoperatively without triggers, and all identified TNEs spontaneously resolved within 2 weeks. The most common symptoms were dysarthria, facial palsy, and numbness around the mouth, followed by sensory disturbance of the upper extremities. The presence of focal hyperperfusion on xenon CT performed immediately after revascularization surgery was strongly correlated with the incidence of TNEs (p = 0.0001). Focal hyperperfusion was observed in 43 of 110 operative sides (39.1%). Notably, only 25.6% of patients with focal hyperperfusion showed numerical global hyperperfusion. In addition, a decrease in CBF compared with the thalamic region in the contralateral side was observed in TNE-affected cases (p = 0.0443). CONCLUSIONS TNEs occurred more frequently in childhood moyamoya disease patients than expected. The clinical background, including symptoms, timing, and duration, was almost identical to TNEs in adults. Focal hyperperfusion, rather than numerical global hyperperfusion, was strongly correlated with the incidence of TNEs. Furthermore, the authors advocate the notion that a clinical course where symptoms occur without triggers may be a unique characteristic of TNEs, especially in childhood moyamoya disease.
Collapse
Affiliation(s)
- Kentaro Chiba
- 1Department of Neurosurgery, Tokyo Women's Medical University, Tokyo
| | - Yasuo Aihara
- 1Department of Neurosurgery, Tokyo Women's Medical University, Tokyo
| | - Atsushi Fukui
- 1Department of Neurosurgery, Tokyo Women's Medical University, Tokyo
| | - Koji Yamaguchi
- 1Department of Neurosurgery, Tokyo Women's Medical University, Tokyo
| | - Akitsugu Kawashima
- 2Department of Neurosurgery, Tokyo Women's Medical University, Yachiyo Medical Center, Chiba; and
| | - Yoshikazu Okada
- 3Department of Neurosurgery, St. Luke's International Hospital, Tokyo, Japan
| | - Takakazu Kawamata
- 1Department of Neurosurgery, Tokyo Women's Medical University, Tokyo
| |
Collapse
|
10
|
Araki Y, Mamiya T, Fujita N, Yokoyama K, Uda K, Kanamori F, Takayanagi K, Ishii K, Nishihori M, Takeuchi K, Tanahashi K, Nagata Y, Nishimura Y, Tanei T, Muraoka S, Izumi T, Kato K, Saito R. Symptomatic hyperperfusion after combined revascularization surgery in patients with pediatric moyamoya disease: patient series. JOURNAL OF NEUROSURGERY: CASE LESSONS 2022. [PMCID: PMC9379730 DOI: 10.3171/case2274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Symptomatic hyperperfusion after cerebral revascularization for pediatric moyamoya disease (MMD) is a rare phenomenon. The authors report a series of patients with this condition. OBSERVATIONS In all three patients in this case series, the combined revascularization was on the left side, the patency of bypass grafts was confirmed after surgery, and focal hyperemia around the anastomotic site was observed on single photon emission computed tomography (SPECT). On the first to eighth days after surgery, all of the patients developed neurological manifestations, including motor aphasia, cheiro-oral syndrome, motor weakness of their right upper limbs, and severe headaches. These symptoms disappeared completely approximately 2 weeks after surgery, and all patients were discharged from the hospital. Quantitative SPECT was performed to determine the proportional change in cerebral blood flow (ΔRCBF) (to ipsilateral cerebellar ratio (denoted ΔRCBF) in the region of interest around the anastomoses, and the mean value was 1.34 (range, 1.29–1.41). LESSONS This rare condition, which develops soon after surgery, requires an accurate diagnosis by SPECT. One indicator is that the ΔRCBF has risen to 1.3 or higher. Subsequently, strategic blood pressure treatment and fluid management could prevent the development of hemorrhagic stroke.
Collapse
Affiliation(s)
- Yoshio Araki
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Takashi Mamiya
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Naotoshi Fujita
- Department of Radiological Technology, Nagoya University Hospital, Aichi, Japan
| | - Kinya Yokoyama
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kenji Uda
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Fumiaki Kanamori
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kai Takayanagi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kazuki Ishii
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Masahiro Nishihori
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kazuhito Takeuchi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kuniaki Tanahashi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Yuichi Nagata
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Yusuke Nishimura
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Takafumi Tanei
- Department of Neurosurgery, Komaki City Hospital, Komaki, Aichi, Japan
| | - Shinsuke Muraoka
- Department of Neurosurgery, Tosei General Hospital, Seto, Aichi, Japan; and
| | - Takashi Izumi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Katsuhiko Kato
- Functional Medical Imaging, Biomedical Imaging Sciences, Division of Advanced Information Health Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Ryuta Saito
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| |
Collapse
|
11
|
Chen JY, Tu XK. Research Progress on Postoperative Transient Neurological Dysfunction in Pediatric and Adult Patients with Moyamoya Disease after Revascularization Surgery. Clin Neurol Neurosurg 2022; 217:107254. [DOI: 10.1016/j.clineuro.2022.107254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/01/2022] [Accepted: 04/13/2022] [Indexed: 11/03/2022]
|
12
|
Araki Y, Yokoyama K, Uda K, Kanamori F, Kurimoto M, Shiba Y, Mamiya T, Takayanagi K, Ishii K, Nishihori M, Takeuchi K, Tanahashi K, Nagata Y, Nishimura Y, Okamoto S, Sumitomo M, Izumi T, Saito R. Paradoxical symptomatic cerebral blood flow decreases after combined revascularization surgery for patients with pediatric moyamoya disease: illustrative case. JOURNAL OF NEUROSURGERY: CASE LESSONS 2022; 3:CASE21628. [PMID: 36130575 PMCID: PMC9379648 DOI: 10.3171/case21628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/29/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Transient neurological deficits (TNDs) develop after cerebral revascularization in patients with moyamoya disease (MMD). The authors report a rare pediatric MMD case with extensive decreased cerebral blood flow (CBF) and prolonged TNDs after combined revascularization. OBSERVATIONS A 9-year-old boy presented with transient left upper limb weakness, and MMD was diagnosed. A right-sided combined surgery was performed. Two years after the surgery, frequent but transient facial (right-sided) and upper limb weakness appeared. The left internal carotid artery terminal stenosis had progressed. Therefore, a left combined revascularization was performed. The patient’s motor aphasia and right upper limb weakness persisted for approximately 10 days after surgery. Magnetic resonance angiography showed that the direct bypass was patent, but extensive decreases in left CBF were observed using single photon emission tomography. With adequate fluid therapy and blood pressure control, the neurological symptoms eventually disappeared, and CBF improved. LESSONS The environment of cerebral hemodynamics is heterogeneous after cerebral revascularization for MMD, and the exact mechanism of CBF decreases was not identified. TNDs are significantly associated with the onset of stroke during the early postoperative period. Therefore, appropriate treatment is desired after determining complex cerebral hemodynamics using CBF studies.
Collapse
Affiliation(s)
- Yoshio Araki
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kinya Yokoyama
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kenji Uda
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Fumiaki Kanamori
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Michihiro Kurimoto
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Yoshiki Shiba
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Takashi Mamiya
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kai Takayanagi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kazuki Ishii
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Masahiro Nishihori
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kazuhito Takeuchi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Kuniaki Tanahashi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Yuichi Nagata
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Yusuke Nishimura
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Sho Okamoto
- Department of Neurosurgery, Aichi Rehabilitation Hospital, Aichi, Japan; and
| | - Masaki Sumitomo
- Department of Neurosurgery, Toyota Kosei Hospital, Aichi, Japan
| | - Takashi Izumi
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Ryuta Saito
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
| |
Collapse
|
13
|
Lu J, Shi G, Zhao Y, Wang R, Zhang D, Chen X, Wang H, Zhao JZ. Effects and safety of aspirin use in patients after cerebrovascular bypass procedures. Stroke Vasc Neurol 2021; 6:624-630. [PMID: 34039715 PMCID: PMC8717793 DOI: 10.1136/svn-2020-000770] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 04/07/2021] [Accepted: 04/20/2021] [Indexed: 11/24/2022] Open
Abstract
Object Superficial temporal artery to middle cerebral artery (STA-MCA) bypass is the most effective treatment for Moyamoya disease (MMD). In this study, we aimed to assess whether aspirin improves STA-MCA bypass patency and is safe in patients with MMD. Methods We performed a retrospective medical record review of patients with ischaemic-onset MMD who had undergone STA-MCA bypass at two hospitals between January 2011 and August 2018, to clarify the effects and safety of aspirin following STA-MCA bypass. The neurological status at the last follow-up (FU) was compared between patients with FU bypass patency and occlusion. Results Among 217 identified patients (238 hemispheres), the mean age was 41.4±10.2 years, and 51.8% were male; the indications for STA-MCA bypass were stroke (48.2%), followed by a transient ischaemic attack (44.0%). Immediate bypass patency was confirmed in all cases. During the FU period (1.5±1.5 y), 15 cases were occluded at FU imaging, resulting in an overall cumulative patency rate of 94%. The patency rates were 93% and 94% in the short-term FU group (n=131, mean FU time 0.5±0.2 years) and long-term FU group (n=107, mean FU time 4.1±3.5 years), respectively. The STA-MCA bypass patency rate in the aspirin group was higher than that in the non-aspirin group (98.7% vs 89.7%; HR 1.57; 95% CI 1.106 to 2.235; p=0.012). No significant difference in the FU haemorrhagic events was observed between the aspirin and non-aspirin groups. Conclusions Among adult patients with ischaemic-onset MMD undergoing STA-MCA bypass procedures, aspirin might increase the bypass patency rate, without increasing the bleeding risk. FU bypass patency may be associated with a better outcome. Additional studies, especially carefully designed prospective studies, are needed to address the role of aspirin after bypass procedures.
Collapse
Affiliation(s)
- Junlin Lu
- Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Guangchao Shi
- Neurosurgery, Peking University International Hospital, Beijing, China
| | - Yuanli Zhao
- Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Neurosurgery, Peking University International Hospital, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Stroke Center, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China.,Beijing Translational Engineering Enter for 3D Printer in Clinical Neuroscience, Beijing, China
| | - Rong Wang
- Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Neurosurgery, Peking University International Hospital, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Stroke Center, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
| | - Dong Zhang
- Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Stroke Center, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
| | - Xiaolin Chen
- Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Stroke Center, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
| | - Hao Wang
- Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China .,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Stroke Center, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China.,Beijing Translational Engineering Enter for 3D Printer in Clinical Neuroscience, Beijing, China
| | - Ji Zong Zhao
- Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Stroke Center, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China.,Beijing Translational Engineering Enter for 3D Printer in Clinical Neuroscience, Beijing, China
| |
Collapse
|