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Ramirez-Velandia F, Young M, Alwakaa O, Han K, Ogilvy CS. Flow Diversion as a Definitive Treatment for Recurrently Ruptured A1-A2 Anterior Cerebral Artery Aneurysm Following Clipping and Coiling. Cureus 2024; 16:e57103. [PMID: 38681287 PMCID: PMC11054312 DOI: 10.7759/cureus.57103] [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: 03/19/2024] [Accepted: 03/27/2024] [Indexed: 05/01/2024] Open
Abstract
Even after clipping of intracranial aneurysms, patients may experience incomplete occlusion or the future recurrence of their treated aneurysm. This paper presents a distinctive case of a recurrent A1-A2 anterior cerebral artery aneurysm that underwent four interventions over 16 years. The aneurysm was treated with two clippings, subsequent coiling, and flow diversion for definitive treatment. The challenges encountered in managing bifurcation aneurysms are discussed, emphasizing the importance of considering hemodynamic factors, vessel geometry, and recurrence risk factors in treatment decisions. The case highlights the need for closer follow-up of ruptured bifurcation aneurysms due to the higher likelihood of recurrence. The role of flow diverters in reinforcing vessel anatomy and preventing recurrence is also highlighted.
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Affiliation(s)
- Felipe Ramirez-Velandia
- Neurological Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Michael Young
- Neurological Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Omar Alwakaa
- Neurological Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Kimberly Han
- Neurological Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Christopher S Ogilvy
- Neurological Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
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Funakoshi Y, Imamura H, Tani S, Adachi H, Fukumitsu R, Sunohara T, Omura Y, Matsui Y, Sasaki N, Fukuda T, Akiyama R, Horiuchi K, Kajiura S, Shigeyasu M, Iihara K, Sakai N. Predictors of Cerebral Aneurysm Rupture after Coil Embolization: Single-Center Experience with Recanalized Aneurysms. AJNR Am J Neuroradiol 2020; 41:828-835. [PMID: 32381548 PMCID: PMC7228172 DOI: 10.3174/ajnr.a6558] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 02/22/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Recanalization after coil embolization is widely studied. However, there are limited data on how recanalized aneurysms rupture. Herein, we describe our experience with the rupture of recanalized aneurysms and discuss the type of recanalized aneurysms at greatest rupture risk. MATERIALS AND METHODS A total of 426 unruptured aneurysms and 169 ruptured aneurysms underwent coil embolization in our institution between January 2009 and December 2017. Recanalization occurred in 38 (8.9%) of 426 unruptured aneurysms (unruptured group) and 37 (21.9%) of 169 ruptured aneurysms (ruptured group). The Modified Raymond-Roy classification on DSA was used to categorize the recanalization type. Follow-up DSA was scheduled until 6 months after treatment, and follow-up MRA was scheduled yearly. If recanalization was suspected on MRA, DSA was performed. RESULTS In the unruptured group, the median follow-up term was 74.0 months. Retreatment for recanalization was performed in 18 aneurysms. Four of 20 untreated recanalized aneurysms (0.94% of total coiled aneurysms) ruptured. In untreated recanalized aneurysms, class IIIb aneurysms ruptured significantly more frequently than class II and IIIa (P = .025). In the ruptured group, the median follow-up term was 28.0 months. Retreatment for recanalization was performed in 16 aneurysms. Four of 21 untreated recanalized aneurysms (2.37% of total coiled aneurysms) ruptured. Class IIIb aneurysms ruptured significantly more frequently than class II and IIIa (P = .02). CONCLUSIONS The types of recanalization after coil embolization may be predictors of rupture. Coiled aneurysms with class IIIb recanalization should undergo early retreatment because of an increased rupture risk.
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Affiliation(s)
- Y Funakoshi
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - H Imamura
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - S Tani
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - H Adachi
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - R Fukumitsu
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - T Sunohara
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - Y Omura
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - Y Matsui
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - N Sasaki
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - T Fukuda
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - R Akiyama
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - K Horiuchi
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - S Kajiura
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - M Shigeyasu
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
| | - K Iihara
- Department of Neurosurgery (K.I.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - N Sakai
- From the Department of Neurosurgery (Y.F., H.I., S.T., H.A., R.F., T.S., Y.O., Y.M., N.Sasaki, T.F., R.A., K.H., S.K., M.S., N.Sakai), Kobe City Medical Center General Hospital, Kobe, Japan
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Morga R, Moskała M, Popiela T, Rajzer M, Wilk A, Kłosiński M, Muszyński T, Trystuła M. Recanalization of Embolized Endovascular Intracranial Aneurysms and Changes in the Blood Viscosity: A Pilot Study. Med Sci Monit 2020; 26:e919059. [PMID: 32231175 PMCID: PMC7146064 DOI: 10.12659/msm.919059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background The purpose of our research was to evaluate the relationships between blood viscosity and recanalization of coiled intracranial aneurysms. Material/Methods The study included consecutives patients treated endovascularly by a team of experienced neurosurgeons and neuroradiologists due to brain aneurysm. A total of 50 patients (the average age was 57.48 years, SD=13.71) were assigned to 2 groups: group A with recanalization (4 male and 8 female patients) and group B without recanalization (10 male and 28 female patients) were examined. All patients underwent a 6-month follow-up of the whole-blood viscosity test with a Brookfield DV III+pro cone-plate viscometer using the Rheocalc program. Differences between groups were assessed using the Statistica 12 computer program (StatSoft Inc., Tulsa, OK, USA). Results Studies have shown no significant difference in the age range between group A and B (P=0.31). In group A, higher viscosity values were found for whole blood [median: 4.14 dyn×sec/cm2 (mPa×sec) quartile range 0.42], compared to group B [median: 3.92 dyn×sec/cm2 (mPa×sec); quartile range 0.40; (P=0.04)]. This difference was significant (P=0.04). Additionally, the level of hematocrit was positively related with recanalization, the higher the hematocrit, the more frequent recanalization. A very strong and statistically significant relationship occurred between the frequency of recanalization and smoking (P<0.001). Conclusions The occurrence of higher values of whole blood viscosity which increase turbulent flow through the vessels may be a risk for recanalization of the coiled intracranial aneurysm.
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Affiliation(s)
- Rafał Morga
- Department of Neurosurgery and Neurotraumatology, Jagiellonian University Medical College, Cracow, Poland
| | - Marek Moskała
- Department of Neurosurgery and Neurotraumatology, Jagiellonian University Medical College, Cracow, Poland
| | - Tadeusz Popiela
- Department of Radiology, Jagiellonian University Medical College, Cracow, Poland
| | - Marek Rajzer
- 1st Department of Cardiology, Invasive Electrocardiology and Arterial Hypertension, Jagiellonian University Medical College, Cracow, Poland
| | - Aleksander Wilk
- Department of Neurosurgery and Neurotraumatology, Jagiellonian University Medical College, Cracow, Poland
| | - Michał Kłosiński
- Department of Anatomy, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland
| | - Tomasz Muszyński
- Department of Vascular Surgery and Endovascular Interventions, John Paul II Hospital, Cracow, Poland
| | - Mariusz Trystuła
- Department of Vascular Surgery and Endovascular Interventions, John Paul II Hospital, Cracow, Poland
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Arai R, Kano H, Suzuki S, Semba H, Arita T, Yagi N, Otsuka T, Matsuno S, Matsuhama M, Kato Y, Uejima T, Oikawa Y, Okumura Y, Yajima J, Yamashita T. Myocardial bridging is an independent predictor of positive spasm provocation testing by intracoronary ergonovine injections: a retrospective observational study. Heart Vessels 2019; 35:474-486. [PMID: 31562555 PMCID: PMC7085475 DOI: 10.1007/s00380-019-01518-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/20/2019] [Indexed: 12/28/2022]
Abstract
The relationship between myocardial bridging (MB) and coronary spasms during spasm provocation testing (SPT) remains unclear. We aimed to investigate whether MB was correlated with the SPT by ergonovine (ER) injections in a retrospective observational study. Of the 3340 patients who underwent a first coronary angiography, 166 underwent SPT using ER injections and were divided into 2 groups: MB(+) (n = 23), and MB(−) (n = 143). MB was defined as an angiographic reduction in the diameter of the coronary artery during systole. The patients who had severe organic stenosis in the left anterior descending coronary artery were excluded. The MB(+) group more frequently had diabetes mellitus and chronic kidney disease, and a thicker interventricular septum thickness. The rate of SPT-positivity was higher in the MB(+) group than MB(−) group (56.5% vs. 22.4%, P = 0.001). A multivariate regression analysis showed that the presence of MB was independently associated with SPT-positivity (odds ratio 5.587, 95% confidence interval 2.061–15.149, P = 0.001). In conclusion, coronary spasms during provocation tests with ER independently correlated with the MB. MB may predict coronary spasms.
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Affiliation(s)
- Riku Arai
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan.
| | - Hiroto Kano
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Shinya Suzuki
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Hiroaki Semba
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Takuto Arita
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Naoharu Yagi
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Takayuki Otsuka
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Shunsuke Matsuno
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Minoru Matsuhama
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Yuko Kato
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Tokuhisa Uejima
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Yuji Oikawa
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Yasuo Okumura
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Junji Yajima
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
| | - Takeshi Yamashita
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Nishiazabu 3-2-19, Minato-ku, Tokyo, 1060031, Japan
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Sheng B, Wu D, Yuan J, Xu S, Li Z, Dong J, Lai N, Fang X. Hemodynamic Characteristics Associated With Paraclinoid Aneurysm Recurrence in Patients After Embolization. Front Neurol 2019; 10:429. [PMID: 31105640 PMCID: PMC6494928 DOI: 10.3389/fneur.2019.00429] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/08/2019] [Indexed: 12/18/2022] Open
Abstract
Objective: To investigate the hemodynamic features before and after embolization of paraclinoidal aneurysms using hemodynamic numerical simulation and the influence of embolization on recurrence after embolization. Methods: From January 2016 to December 2017, we enrolled a total of 113 paraclinoidal aneurysms treated with embolization. They were divided into recurrent group and stable group depending on follow-up results. An aneurysm model was generated based on 3D-DSA before and after embolization. The hemodynamic characteristics were analyzed between two groups using Computational fluid dynamic (CFD). Results: In the recurrent group, the peak systolic WSS, OSI and velocity around the aneurysm neck areas prior to embolization were 20.47 ± 3.04 Pa, 0.06 ± 0.02 and 0.07 ± 0.03 m/s, respectively. These values were 23.50 ± 4.11 Pa, 0.06 ± 0.01 and 0.11 ± 0.02 m/s, respectively in the stable group (P > 0.05). The WSS, OSI, velocity around the same areas in the recurrent group after embolization were 35.59 ± 8.75 Pa, 0.07 ± 0.02 and 0.12 ± 0.03 m/s, respectively (P < 0.01). In the stable group, the WSS, OSI and velocity were 13.08 ± 2.89 Pa, 0.04 ± 0.01 and 0.07 ± 0.02 m/s, respectively (P < 0.01). After embolization, the WSS, OSI and velocity around the aneurysm neck areas in the recurrent group were significantly higher than those in the stable group. Conclusions: High peak systolic WSS, OSI and velocity around aneurysm neck areas after embolization of paraclinoidal aneurysms may be important factors leading to recurrence.
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Affiliation(s)
- Bin Sheng
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Degang Wu
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Jinlong Yuan
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Shanshui Xu
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Zhenbao Li
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Jin Dong
- Department of Nursing, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Niansheng Lai
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Xinggen Fang
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
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Risk factor analysis of recanalization and retreatment for patients with endovascular treatment of internal carotid artery bifurcation aneurysms. Neuroradiology 2018; 60:535-544. [PMID: 29572603 DOI: 10.1007/s00234-018-2013-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 03/13/2018] [Indexed: 01/27/2023]
Abstract
PURPOSE Only a few reports of internal carotid artery (ICA) bifurcation aneurysms using the endovascular technique have been published in the current literature. The purpose of this study was to assess how multiple risk factors including angioarchitectural features of ICA bifurcation characteristics may have influenced aneurysmal rupture, recanalization, and retreatment. METHODS Fifty-one patients with 52 ICA bifurcation aneurysms treated with endovascular coiling between July 2003 and July 2015 were retrospectively analyzed. The patients' clinical records, endovascular reports, and clinical and angiographic outcomes were reviewed. We also evaluated risk factors for recanalization and retreatment, including the angioarchitectural anatomy. RESULTS The clinical outcomes were observed to be satisfactory in 49 patients (96.0%) and unfavorable in 2 patients (4.0%). The risk factor for aneurysmal rupture was young age (P = 0.024). Symptomatic complications due to thromboembolism occurred in 1.9% of cases; no patients suffered a fatal complication. Eleven of 52 ICA bifurcation aneurysms (21.2%) were recanalized within an average of 54.3 ± 33.5 months of follow-up. Among the aneurysms, 4 (7.7%) underwent recoiling. Multivariate analysis showed that ruptured aneurysms (P = 0.006) and a lower packing density (P = 0.048) were risk factors for recanalization. A lower packing density was the only risk factor for retreatment (P = 0.019). CONCLUSION Endovascular treatment of ICA bifurcation aneurysms is considered safe and acceptable. This study showed that the ICA bifurcation aneurysms ruptured more frequently at a younger age. A higher packing density has been shown to reduce major recanalization and retreatment.
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Jeon JP, Cho YD, Yoo DH, Moon J, Lee J, Cho WS, Kang HS, Kim JE, Han MH. Risk Factor Analysis of Recanalization Timing in Coiled Aneurysms: Early versus Late Recanalization. AJNR Am J Neuroradiol 2017; 38:1765-1770. [PMID: 28619836 DOI: 10.3174/ajnr.a5267] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/10/2017] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND PURPOSE Long-term documentation of anatomic and angiographic characteristics pertaining to the timing of recanalization in coiled aneurysms has been insufficient. Our intent was to analyze and compare early and late-phase recanalization after coiling, identifying respective risk factors. MATERIALS AND METHODS A total of 870 coiled saccular aneurysms were monitored for extended periods (mean, 30.8 ± 8.3 months). Medical records and radiologic data were also reviewed, stratifying patients as either early (n = 128) or late (n = 52) recanalization or as complete occlusion (n = 690). Early recanalization was equated with confirmed recanalization within 6 months after the procedure, whereas late recanalization was defined as verifiable recanalization after imaging confirmation of complete occlusion at 6 months. A multinomial regression model served to assess potential risk factors, the reference point being early recanalization. RESULTS Posterior circulation (P = .009), subarachnoid hemorrhage at presentation (P = .011), second attempt for recanalized aneurysm (P < .001), and aneurysm size >7 mm (P < .001) emerged as variables significantly linked with early recanalization (versus complete occlusion). Late (versus early) recanalization corresponded with aneurysms ≤7 mm (P = .013), and in a separate subanalysis of lesions ≤7 mm, aneurysms 4-7 mm showed a significant predilection for late recanalization (P = .008). However, the propensity for complete occlusion in smaller lesions (≤7 mm) increased as the size diminished. CONCLUSIONS Although long-term complete occlusion after coiling was more likely in aneurysms ≤7 mm, such lesions were more prone to late (versus early) recanalization, particularly those of 4-7 mm in size. Long-term follow-up imaging is thus appropriate in aneurysms >4 mm to detect late recanalization of those formerly demonstrating complete occlusion.
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Affiliation(s)
- J P Jeon
- From the Department of Neurosurgery (J.P.J.), Hallym University College of Medicine, Chuncheon, Korea
| | - Y D Cho
- Departments of Radiology (Y.D.C., D.H.Y., J.M.)
| | - D H Yoo
- Departments of Radiology (Y.D.C., D.H.Y., J.M.)
| | - J Moon
- Departments of Radiology (Y.D.C., D.H.Y., J.M.)
| | - J Lee
- Neurosurgery (J.L., W.-S.C., H.-S.K., J.E.K., M.H.H.), Seoul National University College of Medicine, Seoul, Korea
| | - W-S Cho
- Neurosurgery (J.L., W.-S.C., H.-S.K., J.E.K., M.H.H.), Seoul National University College of Medicine, Seoul, Korea
| | - H-S Kang
- Neurosurgery (J.L., W.-S.C., H.-S.K., J.E.K., M.H.H.), Seoul National University College of Medicine, Seoul, Korea
| | - J E Kim
- Neurosurgery (J.L., W.-S.C., H.-S.K., J.E.K., M.H.H.), Seoul National University College of Medicine, Seoul, Korea
| | - M H Han
- Neurosurgery (J.L., W.-S.C., H.-S.K., J.E.K., M.H.H.), Seoul National University College of Medicine, Seoul, Korea
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Tjahjadi M, Kim T, Ojar D, Byoun HS, Lee SU, Ban SP, Hwang G, Kwon OK. Long-term review of selected basilar-tip aneurysm endovascular techniques in a single institution. INTERDISCIPLINARY NEUROSURGERY-ADVANCED TECHNIQUES AND CASE MANAGEMENT 2017. [DOI: 10.1016/j.inat.2017.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Tjahjadi M, Kim T, Ojar D, Byoun HS, Lee SU, Ban SP, Hwang G, Kwon OK. WITHDRAWN: Long-term review of selected basilar-tip aneurysm endovascular techniques in a single institution. INTERDISCIPLINARY NEUROSURGERY 2017. [DOI: 10.1016/j.inat.2017.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Jeon JP, Cho YD, Rhim JK, Yoo DH, Cho WS, Kang HS, Kim JE, Han MH. Fate of Coiled Aneurysms with Minor Recanalization at 6 Months: Rate of Progression to Further Recanalization and Related Risk Factors. AJNR Am J Neuroradiol 2016; 37:1490-5. [PMID: 26965468 DOI: 10.3174/ajnr.a4763] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/28/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Minor recanalization in coiled aneurysms may remain stable with time or may progress to major recanalization. Our aim was to monitor the aneurysms displaying minor recanalization in imaging studies at 6 months, gauging major recanalization rates and related risk factors through extended follow-up. MATERIALS AND METHODS Sixty-five aneurysms (in 65 patients) showing minor recanalization in follow-up imaging at 6 months were reviewed retrospectively. Medical records and radiologic data accruing during extended monitoring (mean, 24.8 ± 8.2 months) were assessed. Univariate and multivariate analyses were conducted to identify risk factors for progression from minor-to-major recanalization. RESULTS Progression to major recanalization was observed in 24 (36.9%) of the initially qualifying aneurysms during a follow-up of 112.5 aneurysm-years, for an annual rate of 17.84% per aneurysm-year. Progression was determined chronologically as follows: 14 (58.3%) at 6 months, 8 (33.3%) at 18 months, and 2 (8.4%) at 30 months. Stent deployment significantly decreased the occurrence of major recanalization (OR = 0.22, P = .03), whereas antiplatelet therapy (OR = 0.82, P = .75), posterior location (OR = 0.24, P = .20), and second coiling for recanalized aneurysms (OR = 0.96, P = .96) were unrelated. CONCLUSIONS Our analysis determined a 36.9% rate of major recanalization during a follow-up of 112.5 aneurysm-years in coiled aneurysms showing minor recanalization at 6 months. Stent deployment alone conferred a protective effect, preventing further recanalization without additional treatment. Given the fair probability of late major recanalization, aneurysms showing minor recanalization at 6 months should be monitored diligently, particularly in the absence of stent placement.
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Affiliation(s)
- J P Jeon
- From the Department of Neurosurgery (J.P.J.), Hallym University College of Medicine, Chuncheon, Korea
| | - Y D Cho
- Departments of Radiology (Y.D.C., J.K.R., D.H.Y., M.H.H.)
| | - J K Rhim
- Departments of Radiology (Y.D.C., J.K.R., D.H.Y., M.H.H.)
| | - D H Yoo
- Departments of Radiology (Y.D.C., J.K.R., D.H.Y., M.H.H.)
| | - W-S Cho
- Neurosurgery (W.s.C., H.-S.K., J.E.K.), Seoul National University College of Medicine, Seoul, Korea
| | - H-S Kang
- Neurosurgery (W.s.C., H.-S.K., J.E.K.), Seoul National University College of Medicine, Seoul, Korea
| | - J E Kim
- Neurosurgery (W.s.C., H.-S.K., J.E.K.), Seoul National University College of Medicine, Seoul, Korea
| | - M H Han
- Departments of Radiology (Y.D.C., J.K.R., D.H.Y., M.H.H.)
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11
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Park W, Song Y, Park KJ, Koo HW, Yang K, Suh DC. Hemodynamic Characteristics Regarding Recanalization of Completely Coiled Aneurysms: Computational Fluid Dynamic Analysis Using Virtual Models Comparison. Neurointervention 2016; 11:30-6. [PMID: 26958410 PMCID: PMC4781914 DOI: 10.5469/neuroint.2016.11.1.30] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 11/24/2022] Open
Abstract
Purpose Hemodynamic factors are considered to play an important role in initiation and progression of the recurrence after endosaccular coiling of the intracranial aneurysms. We made paired virtual models of completely coiled aneurysms which were subsequently recanalized and compared to identify hemodynamic characteristics related to the recurred aneurysmal sac. Materials and Methods We created paired virtual models of computational fluid dynamics (CFD) in five aneurysms which were initially regarded as having achieved complete occlusion and then recurred during follow-up. Paired virtual models consisted of the CFD model of 3D rotational angiography obtained in the recurred aneurysm and the control model of the initial, parent artery after artificial removal of the coiled and recanalized aneurysm. Using the CFD analysis of the virtual model, we analyzed the hemodynamic characteristics on the neck of each aneurysm before and after its recurrence. Results High wall shear stress (WSS) was identified at the cross-sectionally identified aneurysm neck at which recurrence developed in all cases. A small vortex formation with relatively low velocity in front of the neck was also identified in four cases. The aneurysm recurrence locations corresponded to the location of high WSS and/or small vortex formation. Conclusion Recanalized aneurysms revealed increased WSS and small vortex formation at the cross-sectional neck of the aneurysm. This observation may partially explain the hemodynamic causes of future recanalization after coil embolization.
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Affiliation(s)
- Wonhyoung Park
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.; Department of Neurosurgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Yunsun Song
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Kye Jin Park
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Hae-Won Koo
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Kuhyun Yang
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Dae Chul Suh
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
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12
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Cornelissen BMW, Schneiders JJ, Potters WV, van den Berg R, Velthuis BK, Rinkel GJE, Slump CH, VanBavel E, Majoie CBLM, Marquering HA. Hemodynamic Differences in Intracranial Aneurysms before and after Rupture. AJNR Am J Neuroradiol 2015; 36:1927-33. [PMID: 26089313 DOI: 10.3174/ajnr.a4385] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 03/03/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Rupture risk of intracranial aneurysms may depend on hemodynamic characteristics. This has been assessed by comparing hemodynamic data of ruptured and unruptured aneurysms. However, aneurysm geometry may change before, during, or just after rupture; this difference causes potential changes in hemodynamics. We assessed changes in hemodynamics in a series of intracranial aneurysms, by using 3D imaging before and after rupture. MATERIALS AND METHODS For 9 aneurysms in 9 patients, we used MRA, CTA, and 3D rotational angiography before and after rupture to generate geometric models of the aneurysm and perianeurysmal vasculature. Intra-aneurysmal hemodynamics were simulated by using computational fluid dynamics. Two neuroradiologists qualitatively assessed flow complexity, flow stability, inflow concentration, and flow impingement in consensus, by using flow-velocity streamlines and wall shear stress distributions. RESULTS Hemodynamics changed in 6 of the 9 aneurysms. The median time between imaging before and after rupture was 678 days (range, 14-1461 days) in these 6 cases, compared with 151 days (range, 34-183 days) in the 3 cases with unaltered hemodynamics. Changes were observed for flow complexity (n = 3), flow stability (n = 3), inflow concentration (n = 2), and region of flow impingement (n = 3). These changes were in all instances associated with aneurysm displacement due to rupture-related hematomas, growth, or newly formed lobulations. CONCLUSIONS Hemodynamic characteristics of intracranial aneurysms can be altered by geometric changes before, during, or just after rupture. Associations of hemodynamic characteristics with aneurysm rupture obtained from case-control studies comparing ruptured with unruptured aneurysms should therefore be interpreted with caution.
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Affiliation(s)
- B M W Cornelissen
- From the MIRA Institute for Biomedical Engineering and Technical Medicine (B.M.W.C., C.H.S.), University of Twente, Enschede, the Netherlands Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.) Biomedical Engineering and Physics (B.M.W.C, E.V., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands
| | - J J Schneiders
- Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.)
| | - W V Potters
- Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.)
| | - R van den Berg
- Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.)
| | | | - G J E Rinkel
- Neurology and Neurosurgery, Brain Center Rudolf Magnus (G.J.E.R.), University Medical Center Utrecht, Utrecht, the Netherlands
| | - C H Slump
- From the MIRA Institute for Biomedical Engineering and Technical Medicine (B.M.W.C., C.H.S.), University of Twente, Enschede, the Netherlands
| | - E VanBavel
- Biomedical Engineering and Physics (B.M.W.C, E.V., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands
| | - C B L M Majoie
- Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.)
| | - H A Marquering
- Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.) Biomedical Engineering and Physics (B.M.W.C, E.V., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands
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13
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14
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Virtual treatment of basilar aneurysms using shape memory polymer foam. Ann Biomed Eng 2013; 41:725-43. [PMID: 23329002 DOI: 10.1007/s10439-012-0719-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 11/30/2012] [Indexed: 10/27/2022]
Abstract
Numerical simulations are performed on patient-specific basilar aneurysms that are treated with shape memory polymer (SMP) foam. In order to assess the post-treatment hemodynamics, two modeling approaches are employed. In the first, the foam geometry is obtained from a micro-CT scan and the pulsatile blood flow within the foam is simulated for both Newtonian and non-Newtonian viscosity models. In the second, the foam is represented as a porous media continuum, which has permeability properties that are determined by computing the pressure gradient through the foam geometry over a range of flow speeds comparable to those of in vivo conditions. Virtual angiography and additional post-processing demonstrate that the SMP foam significantly reduces the blood flow speed within the treated aneurysms, while eliminating the high-frequency velocity fluctuations that are present within the pre-treatment aneurysms. An estimation of the initial locations of thrombus formation throughout the SMP foam is obtained by means of a low fidelity thrombosis model that is based upon the residence time and shear rate of blood. The Newtonian viscosity model and the porous media model capture similar qualitative trends, though both yield a smaller volume of thrombus within the SMP foam.
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15
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Irie K, Anzai H, Kojima M, Honjo N, Ohta M, Hirose Y, Negoro M. Computational fluid dynamic analysis following recurrence of cerebral aneurysm after coil embolization. Asian J Neurosurg 2013; 7:109-15. [PMID: 23293665 PMCID: PMC3532756 DOI: 10.4103/1793-5482.103706] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hemodynamic factors are thought to play important role in the initiation, growth, and rupture of cerebral aneurysms. However, hemodynamic features in the residual neck of incompletely occluded aneurysms and their influences on recanalization are rarely reported. This study characterized the hemodynamics of incompletely occluded aneurysms that had been confirmed to undergo recanalization during long-term follow-up using computational fluid dynamic analysis. A ruptured left basilar-SCA aneurysm was incompletely occluded and showed recanalization during 11 years follow-up period. We retrospectively characterized on three-dimensional MR angiography. After subtotal occlusion, the flow pattern, wall shear stress (WSS), and velocity at the remnant neck changed during long-term follow-up period. Specifically, high WSS region and high blood flow velocity were found near the neck. Interestingly, these area of the remnant neck coincided with the location of aneurysm recanalization. High WSS and blood flow velocity were consistently observed near the remnant neck of incompletely occluded aneurysm, prone to future recanalization. It will suggest that hemodynamic factors may play important roles in aneurismal recurrence after endovascular treatment.
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Affiliation(s)
- Keiko Irie
- Department of Neurosurgery, Fujita Health University, Toyoake city Aichi 470-1192, Japan
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16
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Li C, Wang S, Chen J, Yu H, Zhang Y, Jiang F, Mu S, Li H, Yang X. Influence of hemodynamics on recanalization of totally occluded intracranial aneurysms: a patient-specific computational fluid dynamic simulation study. J Neurosurg 2012; 117:276-83. [PMID: 22680247 DOI: 10.3171/2012.5.jns111558] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Some totally occluded intracranial aneurysms may recur. The role of hemodynamic mechanisms in this process remains to be elucidated. The authors used computational fluid dynamic analysis and investigated the local hemodynamic characteristics at the aneurysm neck before and after total embolization, attempting to identify hemodynamic risk factors leading to recurrence of totally embolized aneurysms.
Methods
Between May 2008 and June 2010, the authors recruited 17 consecutive patients with totally occluded intracranial aneurysms (7 recanalized and 10 stable lesions). Using patient-specific 3D digital subtraction angiography data, the hemodynamic features before and after embolization were retrospectively characterized.
Results
The overall preembolization blood flow patterns were nearly the same in the recanalized and stable groups, with no significant difference in either the maximum wall shear stress (WSS) (p = 0.914) or the spatially averaged WSS (p = 0.322) at peak systole at the aneurysm neck. After occlusion, the overall flow pattern changed, and the WSS distribution at the treated aneurysm neck differed in the 2 groups. In all of the 7 recanalized cases, both the maximum WSS and spatially averaged WSS at peak systole at the treated aneurysm neck were higher than those at the aneurysm neck before embolization. In contrast, both parameters were decreased in 70%–80% of the stable cases. After embolization, both the maximum WSS (p = 0.021) and spatially averaged WSS (p = 0.041) at peak systole at the treated aneurysm neck were higher in the recanalized group than in the stable group.
Conclusions
Higher WSS at the treated aneurysm neck after total embolization can be an important hemodynamic factor that contributes to aneurysm recurrence after endovascular treatment.
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Affiliation(s)
- Chuanhui Li
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
| | - Shengzhang Wang
- 3Department of Mechanics and Engineering Science, Fudan University, Shanghai; and
| | - Jialiang Chen
- 3Department of Mechanics and Engineering Science, Fudan University, Shanghai; and
| | - Hongyu Yu
- 2Department of Biomedical Engineering, Capital Medical University, Beijing
| | - Ying Zhang
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
| | - Fan Jiang
- 4Key Laboratory of Cardiovascular Remodeling and Function Research, Medical School and Qilu Hospital, Shandong University, Jinan, Shandong Province, China
| | - Shiqing Mu
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
| | - Haiyun Li
- 2Department of Biomedical Engineering, Capital Medical University, Beijing
| | - Xinjian Yang
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
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17
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Ugron Á, Szikora I, Paál G. Haemodynamic changes induced by intrasaccular packing on intracranial aneurysms: A computational fluid dynamic study. Interv Med Appl Sci 2012. [DOI: 10.1556/imas.4.2012.2.4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
Endovascular treatment of intracranial aneurysms is a routine medical practice. The most widely used technique is the packing the aneurysm sac with an embolic material. To gain deeper understanding in the effects of specific treatment methods, the intra-aneurysmal haemodynamics are studied with the help of patient-specific computational models. Numerical simulations demonstrated that embolisation with liquid polymer results in an overall decrease of the wall shear stress and pressure in the aneurysm region. Within the range of clinically relevant packing density, simulation of coil embolisation showed homogenisation and decrease of the wall loads on the aneurysm sac. Increasing the packing density above 20% produces little or no further reduction of intra-aneurysmal flow. Sufficient packing of the aneurysm sac results in significant intra-aneurysmal flow decrease associated with reduced wall loads but locally increased pressure or wall shear stress zones may appear depending on the specific vessel geometry.
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Affiliation(s)
- Ádám Ugron
- 1 Department of Hydrodynamic Systems, Budapest University of Technology and Economics, Budapest, Hungary
- 3 Budapest University of Technology and Economics, P.O. Box 91, H-1521, Budapest, Hungary
| | - István Szikora
- 2 National Institute of Neurosciences, Budapest, Hungary
| | - György Paál
- 1 Department of Hydrodynamic Systems, Budapest University of Technology and Economics, Budapest, Hungary
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18
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Luo B, Yang X, Wang S, Li H, Chen J, Yu H, Zhang Y, Zhang Y, Mu S, Liu Z, Ding G. High shear stress and flow velocity in partially occluded aneurysms prone to recanalization. Stroke 2011; 42:745-53. [PMID: 21233477 DOI: 10.1161/strokeaha.110.593517] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Hemodynamic factors are thought to play an important role in the initiation, growth, and rupture of cerebral aneurysms. However, the hemodynamic features in the residual neck of the partially embolized aneurysms and their influences on recanalization are rarely reported. In this study, we characterized the hemodynamics of partially occluded aneurysms, which were proven to undergo recanalization during follow-up using computational fluid dynamic analysis. METHODS From May 2007 to June 2009, we identified 11 partial aneurysms during follow-up, including 5 recanalized cases and 6 stable cases with 3-dimensional digital subtraction angiography. We retrospectively characterized the hemodynamic features around the residual aneurysmal pouch using the available postprocedural digital subtraction angiography image data. The occluded part of the aneurysm was regarded as completely separated from the circulation. RESULTS The overall blood flow patterns before embolization were almost the same in the recanalized and stable groups. After occlusion, the flow pattern changes, wall shear stress (WSS), and velocity at the remnant neck demonstrated different changes between the 2 groups. Specifically, in the recanalized group, high WSS regions were found near the neck in all 5 cases, with 4 of them being even higher than those before occlusion. Interestingly, in all cases, the high WSS area of the remnant neck coincided with the location where the aneurysm recanalization occurred. In the stable group, 5 out of 6 cases demonstrated lower WSS and velocity at the remnant neck after occlusion. CONCLUSIONS High WSS and blood flow velocity were consistently observed near the remnant neck of partially embolized aneurysms prone to future recanalization, suggesting that hemodynamic factors may have an important role in aneurysmal recurrence after endovascular treatment. The difference in flow pattern could be caused by the incomplete occlusion of the aneurysms.
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Affiliation(s)
- Bin Luo
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Tiantan Xili 6, Chongwen District, Beijing 100050, China
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19
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Temporal variations of wall shear stress parameters in intracranial aneurysms--importance of patient-specific inflow waveforms for CFD calculations. Acta Neurochir (Wien) 2010; 152:1391-8; discussion 1398. [PMID: 20390310 DOI: 10.1007/s00701-010-0647-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE To assess reliability of wall shear stress (WSS)calculations using computational fluid dynamics (CFD) dependent on inflow in internal carotid artery aneurysms (ICA). MATERIALS AND METHODS Six unruptured ICA aneurysms were studied. 3D computational meshes were created from 3D digital subtraction angiographic images (Axiom Artis dBA, Siemens Medical Solutions). Transient CFD simulations(Fluent, ANSYS Inc.) were performed for two inflow conditions: (1) idealized averaged waveform from normal subjects (ID) and (2) patient-specific waveform (PS)measured with 2D phase contrast magnetic resonance imaging. Stability of calculation was assessed by comparing mean WSS (<WSS>), temporal wall shear stress magnitude variation (Delta WSS), and oscillatory shear index(OSI, a measure of variation in the WSS direction) on the aneurysmal wall for both conditions. RESULTS For all cases, mean relative difference (PS-ID) of WSS (<WSS>) was -15% (range -32% to 11%). Mean Delta WSS difference was -29.3% ( -100% to 67%). Mean OSI difference was 7.5% (-12% to 40%). Large variations in histograms of these parameters were noted. CONCLUSION For accurate calculations of WSS parameters,patient-specific information on physiological flow may be necessary. Results obtained with averaged or idealized flow waveforms may have to be interpreted with caution.
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20
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Ford MD, Hoi Y, Piccinelli M, Antiga L, Steinman DA. An objective approach to digital removal of saccular aneurysms: technique and applications. Br J Radiol 2010; 82 Spec No 1:S55-61. [PMID: 20348537 DOI: 10.1259/bjr/67593727] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Human studies of haemodynamic factors in the pathogenesis of cerebral aneurysms require knowledge of the pre-aneurysmal vasculature. This paper presents an objective and automated technique to digitally remove an aneurysm and reconstruct the parent artery, based on lumen geometries segmented from angiographic images. Relying on robust computational geometry concepts, notably Voronoi diagrams of the digitised lumen surface, the aneurysm attachment region is first defined objectively using lumen centrelines. Centrelines within this region are replaced by smooth interpolations, which then guide the interpolation of Voronoi points within the attachment region. Combined with Voronoi points from outside the attachment region, the parent artery lumen, without the aneurysm, can be reconstructed. Plausible reconstructions were obtained, automatically, for a set of 10 side-wall or terminal aneurysms, of various sizes and shapes, from the ANEURISK project data set. Application of image-based computational fluid dynamics analysis to a five side-wall aneurysm cases data set revealed an association between the recently proposed gradient oscillatory number (GON) and the site of aneurysm formation in four of five cases; however, elevated GON was also evident at non-aneurysmal sites. A potential application to the automated delineation of aneurysms for morphological characterisations is also suggested. The proposed approach may serve as a broad platform for investigating haemodynamic and morphological factors in aneurysm initiation, rupture and therapy in a way amenable to large-scale clinical studies or routine clinical use. Nevertheless, while the parent artery reconstructions are plausible, it remains to be proven that they are faithful representations of the pre-aneurysmal artery.
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Affiliation(s)
- M D Ford
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
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Small W, Singhal P, Wilson TS, Maitland DJ. Biomedical applications of thermally activated shape memory polymers. JOURNAL OF MATERIALS CHEMISTRY 2010; 20:3356-3366. [PMID: 21258605 PMCID: PMC3023912 DOI: 10.1039/b923717h] [Citation(s) in RCA: 213] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Shape memory polymers (SMPs) are smart materials that can remember a primary shape and can return to this primary shape from a deformed secondary shape when given an appropriate stimulus. This property allows them to be delivered in a compact form via minimally invasive surgeries in humans, and deployed to achieve complex final shapes. Here we review the various biomedical applications of SMPs and the challenges they face with respect to actuation and biocompatibility. While shape memory behavior has been demonstrated with heat, light and chemical environment, here we focus our discussion on thermally stimulated SMPs.
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Affiliation(s)
- Ward Small
- Lawrence Livermore National Laboratory, Livermore, California, 94550, USA
| | - Pooja Singhal
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, 77843, USA
| | - Thomas S. Wilson
- Lawrence Livermore National Laboratory, Livermore, California, 94550, USA
| | - Duncan J. Maitland
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, 77843, USA
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