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1,322 results on '"Scott, Simon"'

51. Supplementary Figure 2 from Inhibition of Repair of Radiation-Induced DNA Damage Enhances Gene Expression from Replication-Defective Adenoviral Vectors

Author

Hingorani, Mohan, primary, White, Christine L., primary, Merron, Andrew, primary, Peerlinck, Inge, primary, Gore, Martin E., primary, Slade, Andrew, primary, Scott, Simon D., primary, Nutting, Christopher M., primary, Pandha, Hardev S., primary, Melcher, Alan A., primary, Vile, Richard G., primary, Vassaux, Georges, primary, and Harrington, Kevin J., primary

Published
2023
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52. Supplementary Figure 4 from Use of Macrophages to Target Therapeutic Adenovirus to Human Prostate Tumors

Author

Muthana, Munitta, primary, Giannoudis, Athina, primary, Scott, Simon D., primary, Fang, Hsin-Yu, primary, Coffelt, Seth B., primary, Morrow, Fiona J., primary, Murdoch, Craig, primary, Burton, Julian, primary, Cross, Neil, primary, Burke, Bernard, primary, Mistry, Roshna, primary, Hamdy, Freddie, primary, Brown, Nicola J., primary, Georgopoulos, Lindsay, primary, Hoskin, Peter, primary, Essand, Magnus, primary, Lewis, Claire E., primary, and Maitland, Norman J., primary

Published
2023
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53. Supplementary Figure 1 from Use of Macrophages to Target Therapeutic Adenovirus to Human Prostate Tumors

Author

Muthana, Munitta, primary, Giannoudis, Athina, primary, Scott, Simon D., primary, Fang, Hsin-Yu, primary, Coffelt, Seth B., primary, Morrow, Fiona J., primary, Murdoch, Craig, primary, Burton, Julian, primary, Cross, Neil, primary, Burke, Bernard, primary, Mistry, Roshna, primary, Hamdy, Freddie, primary, Brown, Nicola J., primary, Georgopoulos, Lindsay, primary, Hoskin, Peter, primary, Essand, Magnus, primary, Lewis, Claire E., primary, and Maitland, Norman J., primary

Published
2023
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54. Supplementary Figure 3 from Use of Macrophages to Target Therapeutic Adenovirus to Human Prostate Tumors

Author

Muthana, Munitta, primary, Giannoudis, Athina, primary, Scott, Simon D., primary, Fang, Hsin-Yu, primary, Coffelt, Seth B., primary, Morrow, Fiona J., primary, Murdoch, Craig, primary, Burton, Julian, primary, Cross, Neil, primary, Burke, Bernard, primary, Mistry, Roshna, primary, Hamdy, Freddie, primary, Brown, Nicola J., primary, Georgopoulos, Lindsay, primary, Hoskin, Peter, primary, Essand, Magnus, primary, Lewis, Claire E., primary, and Maitland, Norman J., primary

Published
2023
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55. Supplementary Figure 5 from Use of Macrophages to Target Therapeutic Adenovirus to Human Prostate Tumors

Author

Muthana, Munitta, primary, Giannoudis, Athina, primary, Scott, Simon D., primary, Fang, Hsin-Yu, primary, Coffelt, Seth B., primary, Morrow, Fiona J., primary, Murdoch, Craig, primary, Burton, Julian, primary, Cross, Neil, primary, Burke, Bernard, primary, Mistry, Roshna, primary, Hamdy, Freddie, primary, Brown, Nicola J., primary, Georgopoulos, Lindsay, primary, Hoskin, Peter, primary, Essand, Magnus, primary, Lewis, Claire E., primary, and Maitland, Norman J., primary

Published
2023
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56. Data from Use of Macrophages to Target Therapeutic Adenovirus to Human Prostate Tumors

Author

Muthana, Munitta, primary, Giannoudis, Athina, primary, Scott, Simon D., primary, Fang, Hsin-Yu, primary, Coffelt, Seth B., primary, Morrow, Fiona J., primary, Murdoch, Craig, primary, Burton, Julian, primary, Cross, Neil, primary, Burke, Bernard, primary, Mistry, Roshna, primary, Hamdy, Freddie, primary, Brown, Nicola J., primary, Georgopoulos, Lindsay, primary, Hoskin, Peter, primary, Essand, Magnus, primary, Lewis, Claire E., primary, and Maitland, Norman J., primary

Published
2023
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57. Genetic characterization of a new candidate hemagglutinin subtype of influenza A viruses

Author

Fereidouni, Sasan, Starick, Elke, Karamendin, Kobey, Di Genova, Cecilia, Scott, Simon D., Khan, Yelizaveta, Harder, Timm, Kydyrmanov, Aidyn, Fereidouni, Sasan, Starick, Elke, Karamendin, Kobey, Di Genova, Cecilia, Scott, Simon D., Khan, Yelizaveta, Harder, Timm, and Kydyrmanov, Aidyn

Abstract

Avian influenza viruses (AIV) have been classified on the basis of 16 subtypes of hemagglutinin (HA) and 9 subtypes of neuraminidase. Here we describe genomic evidence for a new candidate HA subtype, nominally H19, with a large genetic distance to all previously described AIV subtypes, derived from a cloacal swab sample of a Common Pochard (Aythya ferina) in Kazakhstan, in 2008. Avian influenza monitoring in wild birds especially in migratory hotspots such as central Asia is an important approach to gain information about the circulation of known and novel influenza viruses. Genetically, the novel HA coding sequence exhibits only 68.2% nucleotide and 68.5% amino acid identity with its nearest relation in the H9 (N2) subtype. The new HA sequence should be considered in current genomic diagnostic AI assays to facilitate its detection and eventual isolation enabling further study and antigenic classification.

Published
2023

58. Correlation between pseudotyped virus and authentic virus neutralisation assays, a systematic review and meta-analysis of the literature

Author

Cantoni, Diego, Wilkie, Craig, Bentley, Emma, Mayora-Neto, Martin, Wright, Edward, Scott, Simon D., Ray, Surajit, Castillo-Olivares, Javier, Heeney, Jonathan L., Mattiuzzo, Giada, Temperton, Nigel J., Cantoni, Diego, Wilkie, Craig, Bentley, Emma, Mayora-Neto, Martin, Wright, Edward, Scott, Simon D., Ray, Surajit, Castillo-Olivares, Javier, Heeney, Jonathan L., Mattiuzzo, Giada, and Temperton, Nigel J.

Abstract

The virus neutralization assay is a principal method to assess the efficacy of antibodies in blocking viral entry. Due to biosafety handling requirements of viruses classified as hazard group 3 or 4, pseudotyped viruses can be used as safer alternative. However, it is often queried how well the results derived from pseudotyped viruses correlate with authentic virus. This systematic review and meta-analysis was designed to comprehensively evaluate the correlation between the two assays.Methods: Using PubMed and Google Scholar, reports that incorporated neutralisation assays with both pseudotyped virus, authentic virus, and the application of a mathematical formula to assess the relationship between the results, were selected for review. Our searches identified 67 reports, of which 22 underwent a three-level meta-analysis.The three-level meta-analysis revealed a high level of correlation between pseudotyped viruses and authentic viruses when used in an neutralisation assay. Reports that were not included in the meta-analysis also showed a high degree of correlation, with the exception of lentiviral-based pseudotyped Ebola viruses.Pseudotyped viruses identified in this report can be used as a surrogate for authentic virus, though care must be taken in considering which pseudotype core to use when generating new uncharacterised pseudotyped viruses.

Published
2023

59. Serological evidence of high pathogenicity virus infection in Eidolon helvum fruit bats in Nigeria

Author

Cantoni, Diego, Mayora-Neto, Martin, Auld, Bethany, Da Costa, Kelly, Del Rosario, Joanne, Ameh, Veronica O., Sabeta, Claude T., Derveni, Mariliza, Hamlet, Arran, Wright, Edward, Scott, Simon, Giotis, Efstathios S., Banyard, Ashley, Temperton, Nigel, Cantoni, Diego, Mayora-Neto, Martin, Auld, Bethany, Da Costa, Kelly, Del Rosario, Joanne, Ameh, Veronica O., Sabeta, Claude T., Derveni, Mariliza, Hamlet, Arran, Wright, Edward, Scott, Simon, Giotis, Efstathios S., Banyard, Ashley, and Temperton, Nigel

Abstract

The Eidolon helvum fruit bat is the most widely distributed fruit bat in Africa and is known to be a reservoir for several pathogenic viruses that can cause disease in humans. To assess the risk of zoonotic spillover, we conducted a serological survey of 304 serum samples from E. helvum bats that were captured for human consumption in Makurdi, Nigeria. Using pseudotyped viruses, we screened the samples for neutralising antibodies against viruses from the Coronaviridae, Filoviridae, Orthomyxoviridae and Paramyxoviridae families. We report the presence of neutralising antibodies against henipavirus lineage GH-M74a virus (odds ratio 6.23; p<0.001), Nipah virus (odds ratio 4.04; p=0.00031), bat influenza H17N10 virus (odds ratio 7.25; p<0.001) and no significant association with Ebola virus (odds ratio 0.56; p=0.375) in the bat cohort. The data suggest a potential risk of zoonotic spillover including the possible circulation of highly pathogenic viruses in E. helvum populations. These findings highlight the importance of maintaining sero-surveillance of E. helvum to monitor changes in virus prevalence and distribution over time and across different geographic locations.

Published
2023

60. Serological evidence of virus infection in Eidolon helvum fruit bats: implications for bushmeat consumption in Nigeria

Author

Cantoni, Diego, Mayora-Neto, Martin, Derveni, Mariliza, da Costa, Kelly, Del Rosario, Joanne, Ameh, Veronica O., Sabeta, Claude T., Auld, Bethany, Hamlet, Arran, Jones, Ian M., Wright, Edward, Scott, Simon D., Giotis, Efstathios S., Banyard, Ashley C., Temperton, Nigel, Cantoni, Diego, Mayora-Neto, Martin, Derveni, Mariliza, da Costa, Kelly, Del Rosario, Joanne, Ameh, Veronica O., Sabeta, Claude T., Auld, Bethany, Hamlet, Arran, Jones, Ian M., Wright, Edward, Scott, Simon D., Giotis, Efstathios S., Banyard, Ashley C., and Temperton, Nigel

Abstract

Introduction: The Eidolon helvum fruit bat is one of the most widely distributed fruit bats in Africa and known to be a reservoir for several pathogenic viruses that can cause disease in animals and humans. To assess the risk of zoonotic spillover, we conducted a serological survey of 304 serum samples from E. helvum bats that were captured for human consumption in Makurdi, Nigeria. Methods: Using pseudotyped viruses, we screened 304 serum samples for neutralizing antibodies against viruses from the Coronaviridae, Filoviridae, Orthomyxoviridae and Paramyxoviridae families. Results: We report the presence of neutralizing antibodies against henipavirus lineage GH-M74a virus (odds ratio 6.23; p < 0.001), Nipah virus (odds ratio 4.04; p = 0.00031), bat influenza H17N10 virus (odds ratio 7.25; p < 0.001) and no significant association with Ebola virus (odds ratio 0.56; p = 0.375) in this bat cohort. Conclusion: The data suggest a potential risk of zoonotic spillover including the possible circulation of highly pathogenic viruses in E. helvum populations. These findings highlight the importance of maintaining sero-surveillance of E. helvum, and the necessity for further, more comprehensive investigations to monitor changes in virus prevalence, distribution over time, and across different geographic locations.

Published
2023

61. Studying longitudinal neutralising antibody levels against Equid herpesvirus 1 in experimentally infected horses using a novel pseudotype based assay

Author

Di Genova, Cecilia, Sutton, Gabrielle, Paillot, Romain, Temperton, Nigel J., Pronost, Stéphane, Scott, Simon D., Di Genova, Cecilia, Sutton, Gabrielle, Paillot, Romain, Temperton, Nigel J., Pronost, Stéphane, and Scott, Simon D.

Abstract

Infection with equid herpesvirus 1 (EHV-1), a DNA virus of the Herpesviridae family represents a significant welfare issue in horses and a great impact on the equine industry. During EHV-1 infection, entry of the virus into different cell types is complex due to the presence of twelve glycoproteins (GPs) on the viral envelope. To investigate virus entry mechanisms, specific combinations of GPs were pseudotyped onto lentiviral vectors. Pseudotyped virus (PV) particles bearing gB, gD, gH and gL were able to transduce several target cell lines (HEK293T/17, RK13, CHO-K1, FHK-Tcl3, MDCK I & II), demonstrating that these four EHV-1 glycoproteins are both essential and sufficient for cell entry. The successful generation of an EHV-1 PV permitted development of a PV neutralisation assay (PVNA). The efficacy of the PVNA was tested by measuring the level of neutralising serum antibodies from EHV-1 experimentally infected horses (n=52) sampled in a longitudinal manner. The same sera were assessed using a conventional EHV-1 virus neutralisation (VN) assay, exhibiting a strong correlation (r=0.82) between the two assays. Furthermore, PVs routinely require -80°C for long term storage and a dry ice cold-chain during transport, which can impede dissemination and utilisation in other stakeholder laboratories. Consequently, lyophilisation of EHV-1 PVs was conducted to address this issue. PVs were lyophilised and pellets either reconstituted immediately or stored under various temperature conditions for different time periods. The recovery and functionality of these lyophilised PVs was compared with standard frozen aliquots in titration and neutralisation tests. Results indicated that lyophilisation could be used to stably preserve such complex herpesvirus pseudotypes, even after weeks of storage at room temperature, and that reconstituted EHV-1 PVs could be successfully employed in antibody neutralisation tests.

Published
2023

62. Stabilisation of isocyanate cross linked polybutadiene binder

Author

Scott, Simon M.

Subjects
660, Chemical Engineering, Applied Chemistry, Chemical Engineering
Abstract

Isocyanate cross-linked hydroxy terminated polybutadiene is used as a binder for solid rocket propellant. Rocket motors containing this propellant require a storage life of at least 20 years. During storage it has been found that the important rubbery properties of the binder can be lost due to oxidative cross-linking of the polybutadiene chains. This could cause catastrophic failure when the rocket motor is required. At present the bis-hindered phenol Calco 2246 is used as a thermal oxidative stabiliser, but it's performance is only adequate. This has led to the search for a more efficient stabiliser system. To hasten the evaluation of new antioxidant systems the use of dynamic thermal analysis was investigated. Results showed that a tentative relationship existed between predictions by thermal analysis and the long term oven ageing for simple single antioxidant systems. But for more complex systems containing either autosynergistic or mixed antioxidants no relationship was observed suggesting that results for such an "accelerated" technique cannot be used for the purpose of extrapolation for long term performance. This was attributed to the short time and more aggressive condition used (hjgher temperature and oxygen rich atmosphere in thermal analysis) altering the mechanism of action of the antioxidants and not allowing time for co-operative effect of the combined antioxidant system to form. One potential problem for the binder system is the use of an diisocyanate as a cross-linking agent. This reacts with the hydroxyl hydrogen on the polymer as well as other active hydrogens such as those contained in a number of antioxidants, affecting both cross-linking and antioxidant effectiveness. Studies in this work showed that only antioxidants containing amine moieties have a significant affect on binder preparation, with the phenolic antioxidants not reacting. This is due to the greater nucleophilicity of the amines. Investigation of a range of antioxidant systems, including potentially homo, hetero and autosynergistic systems, has highlighted a number of systems which show considerably greater effectiveness than the currently used antioxidant Calco 2246. The only single antioxidant which showed improvement was the partially unhindered phenol y-Tocopherol. Of the mixed systems combinations of the sulphur containing antioxidants e.g. DLTP with higher levels of chain-breaking antioxidants, especially Calco 2246, were the most promising. Also the homosynergistic mix of an aromatic amine and a phenol was seen to be very effective but the results were inconsistent. This inconsistency could be explained by the method of sample preparation used. It was shown that the efficiency of a number of antioxidant.s could be dramatically improved by the use of ultrasound during the mixing stage of preparation. The reason for this increase in performance is unclear but in the case of the homosynergistic amine/phenol mix both more efficient mixing and/or the production of a novel mechanism of action are suggested.

Published
1998
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63. Franchising in food retailing : a marketing channels perspective

Author

Scott, Simon Paul

Subjects
381, Internal and EU commerce & consumer affairs
Abstract

This study deals with franchising as a form of distribution in the UK food retail environment. Franchise systems have increased their penetration of food retail markets since the mid 1980's and are frequently commented on by industry observers as being a form of distribution likely to expand aggressively. This study comments on the potential for further franchise development and looks at the association and relationship between franchisor Satisfaction and prevailing environmental conditions from a marketing channels perspective. Because of the paucity of literature, data, statistics and law on franchising, this study uses the marketing channels literature as its theoretical basis. This body of theory is principally used to derive and test hypotheses concerning franchisor satisfaction and the environment. The approach focused on interpreting the results of test for an association and relationship between satisfaction and the environment, to comment on the prospects for further franchising development, and to simultaneously contribute to the increased specification of marketing channels theory. The specific objectives of the study were i) To comment on franchising development and its prospects from an operational perspective by understanding the character and valence of franchisor satisfaction. ii). To develop the specification of marketing channels theory in two areas. First, to examine the content, domain and character of channel member satisfaction from a franchisor's perspective, by looking at the relative importance of behavioural, strategic and corporate image based dimensions. Previous marketing channels studies have only considered franchisee satisfaction in relation to franchisor power. Second, to examine whether the variable of franchisor satisfaction has any association or relationship with external concepts of the environment, these were capacity, concentration, stability, complexity and conflict. iii) To utilise and comment on the robustness of the political economy environmental model as a theoretical and methodological approach to empirical testing of organisational and environmental concepts. Two data gathering exercises were undertaken for the study. First, an extensive number of in-depth interviews were conducted with industry practitioners in franchise firms and trade associations, and second an 8 page questionnaire was mailed to the apparent universe of 45 food franchising firms. Franchisor satisfaction was measured using a seven point, bi polar rating scale and instrumentality importance weights. The environmental concepts were measured by seven point monopolar rating scales. Descriptive statistics, correlation analysis and the multivariate techniques of factor analysis and discriminant analysis are used to analyse and interpret the results. The study reveals that i) from an operational perspective, 90% of franchisors were satisfied with their systems performance at the time of the analysis. They scored the behavioural dimensions regarding interaction with franchisees as more important to their organisation achieving its goals and objectives than strategic or image based dimensions. Instrumentality importance weights were shown not to affect franchisor satisfaction scores. ii) From a theoretical point of view, franchisor satisfaction has a negative association with environmental complexity and a positive association with environmental capacity. There is empirical evidence that discriminant functions of independent environmental variables are able to predict franchisor membership of satisfied and non satisfied groups. Statistically significant results were obtained when the analysis was conducted at an individual environmental variable level, but not at the concept level. iii) The political economy model was shown to be a robust theoretical platform for model and measure development. The model provided an approach which in analysis discriminated between concepts and behaved in a nomological way. Confirmatory factor analysis of two environmental concepts. complexity and stability, extracted factors which were consistent with the sectors of the model which were used to develop the concept measures. The findings suggest that i) under conditions of low environmental complexity and high environmental capacity we should expect higher levels of franchisor satisfaction and expansion of franchising systems. ii) The concept of franchisor satisfaction is multi dimensional and ranks behavioural aspects of the franchise relationship ahead of strategic or image attributes in goal and objective achievement. The franchisor is concerned with higher level strategic issues compared to the franchisee. Under these circumstances, franchisor satisfaction was shown to be associated and related to external concepts and variables, which is an advancement in marketing channel theory. This is because it indicates that in considering organisational satisfaction, the researcher may be overlooking important attributes of the concept if only internal organisational phenomena are considered.

Published
1998

65. Abstract 133: Over Estimation Of Percent Stenosis By Physician Operators May Lead To Carotid Stent Over Utilization

Author

Francis Jareczek, Mary B FARRELL, Erik Lehman, Cathy A Sila, John Terry, DAVID SACKS, Paul Kalapos, Scott Simon, and Kevin M Cockroft

Subjects
Advanced and Specialized Nursing, Neurology (clinical), Cardiology and Cardiovascular Medicine
Abstract

Introduction: Based largely on the inclusion criteria of clinical trials, the degree of cervical carotid artery stenosis is often used as an indication for stent placement in the setting of carotid atherosclerotic disease. However, the rigor and consistency with which such stenosis is measured outside of clinical trials is unclear. We compared the percent stenosis as measured by real world physician operators to that measured by independent expert reviewers. Hypothesis: We hypothesized that the documented degree of stenosis, termed operator-reported stenosis (ORS), from real world facilities performing carotid stent placement would be larger than the reviewer-measured stenosis (RMS) as assessed by clinicians experienced in treating carotid artery disease. Methods: Images were selected from patient cases used for carotid stenting facility accreditation. Data collected included demographics, National Institutes of Health Stroke Scale, modified Rankin Score, and the documented degree of stenosis (ORS). The ORS was compared to the RMS, derived from a panel of expert clinicians. Results: A total of 68 angiograms were reviewed from 39 symptomatic and 29 asymptomatic patients. The RMS values demonstrated excellent agreement with an intra-class correlation of 0.80. The median ORS was 90.0% (IQR 80.0, 90.0) versus a median RMS of 61.1% (IQR 49.8, 73.6), with a median difference of 21.8% (IQR 13.7, 34.4), p < 0.001. This discrepancy persisted within several subpopulations and was larger among asymptomatic patients and those treated at facilities granted delayed accreditation. Based on RMS values, 72% of symptomatic patients and only 10% of asymptomatic patients would meet the Centers for Medicare and Medicaid Services criteria for carotid stent placement. Conclusions: Real world operators tend to overestimate cervical carotid artery stenosis compared to external expert reviewers. Since decisions regarding carotid revascularization are often based at least partially on percent stenosis, such measuring discrepancies inevitably lead to a higher volume of procedures, which may in turn represent a degree of procedural over utilization.

Published
2023

66. Abstract WP3: The Use Of Monitored Anesthesia Care In Place Of Nurse Administered Conscious Sedation Does Not Result In Delays To Emergent Thrombectomy

Author

Cesar Velasco, Varun Padmanaban, Alicia M Richardson, Erin Cekovich, Raymond K Reichwein, Ephraim W Church, David Wilkinson, Scott Simon, and Kevin M Cockroft

Subjects
Advanced and Specialized Nursing, Neurology (clinical), Cardiology and Cardiovascular Medicine
Abstract

Introduction: There has been considerable emphasis on the use of monitored anesthesia care (MAC) versus general anesthesia for emergent mechanical thrombectomy (EMT). However, due to concerns over potential delays many centers do not involve anesthesia services but instead rely on nurse administered conscious sedation (NACS). Since our center switched from NACS to MAC in 2020, we decided to investigate the impact of this switch on our thrombectomy procedures. Methods: Using a prospectively maintained Comprehensive Stroke Center quality improvement database, we reviewed our hospital EMT cases from June 2018 to April 2020 (pre-anesthesia involvement, NACS only) and May 2020 to March 2022 (post-anesthesia involvement). Main inclusion criteria were evidence of a proximal LVO and emergent transport for EMT. Variables reviewed included, time to arterial access from neurointerventional suite arrival, time to first pass, and time to TICI 2b/3. Median outcomes were compared using Mann-Whitney U test. Results: From June 2018 through April 2020 there were a total of 146 LVO cases that received EVT, compared to a total of 209 LVO cases receiving EVT from May 2020 to March 2022. The median time to arterial access from arrival in the neurointerventional suite was significantly longer before anesthesia involvement (June 2018 to April 2020, 16 minutes) compared to the period after anesthesia involvement (May 2020 to March 2022, 10 minutes) (p < 0.0001). There was no significant difference in median time to first pass between the pre-anesthesia (25 minutes) versus post-anesthesia (26 minutes) time frame (p = 0.43). Median time to TICI 2b/3 was faster post-anesthesia (35 minutes) versus pre-anesthesia (40 minutes) involvement (p = 0.19). Conclusion: Our data suggests faster arterial access for EMT and no significant increase in time to first pass or final recanalization after starting to use anesthesia services. The reasons for this are likely multifactorial but may include the offloading of operator responsibilities for managing sedation, blood pressure, and airway security in these often critically ill LVO stroke patients.

Published
2023

93. Stereotactic radiosurgery with versus without prior Onyx embolization for brain arteriovenous malformations

Author

Ching-Jen Chen, Dale Ding, Cheng-Chia Lee, Kathryn N. Kearns, I. Jonathan Pomeraniec, Christopher P. Cifarelli, David E. Arsanious, Roman Liscak, Jaromir Hanuska, Brian J. Williams, Mehran B. Yusuf, Shiao Y. Woo, Natasha Ironside, Rebecca M. Burke, Ronald E. Warnick, Daniel M. Trifiletti, David Mathieu, Monica Mureb, Carolina Benjamin, Douglas Kondziolka, Caleb E. Feliciano, Rafael Rodriguez-Mercado, Kevin M. Cockroft, Scott Simon, Heath B. Mackley, Samer G. Zammar, Neel T. Patel, Varun Padmanaban, Nathan Beatson, Anissa Saylany, John Y. K. Lee, and Jason P. Sheehan

Subjects
medicine.medical_specialty, business.industry, medicine.medical_treatment, Arteriovenous malformation, General Medicine, medicine.disease, Asymptomatic, Article, Radiosurgery, 03 medical and health sciences, 0302 clinical medicine, 030220 oncology & carcinogenesis, parasitic diseases, Cohort, Propensity score matching, medicine, Embolization, Radiology, medicine.symptom, business, Complication, Stroke, 030217 neurology & neurosurgery
Abstract

OBJECTIVE Investigations of the combined effects of neoadjuvant Onyx embolization and stereotactic radiosurgery (SRS) on brain arteriovenous malformations (AVMs) have not accounted for initial angioarchitectural features prior to neuroendovascular intervention. The aim of this retrospective, multicenter matched cohort study is to compare the outcomes of SRS with versus without upfront Onyx embolization for AVMs using de novo characteristics of the preembolized nidus. METHODS The International Radiosurgery Research Foundation AVM databases from 1987 to 2018 were retrospectively reviewed. Patients were categorized based on AVM treatment approach into Onyx embolization (OE) and SRS (OE+SRS) or SRS alone (SRS-only) cohorts and then propensity score matched in a 1:1 ratio. The primary outcome was AVM obliteration. Secondary outcomes were post-SRS hemorrhage, all-cause mortality, radiological and symptomatic radiation-induced changes (RICs), and cyst formation. Comparisons were analyzed using crude rates and cumulative probabilities adjusted for competing risk of death. RESULTS The matched OE+SRS and SRS-only cohorts each comprised 53 patients. Crude rates (37.7% vs 47.2% for the OE+SRS vs SRS-only cohorts, respectively; OR 0.679, p = 0.327) and cumulative probabilities at 3, 4, 5, and 6 years (33.7%, 44.1%, 57.5%, and 65.7% for the OE+SRS cohort vs 34.8%, 45.5%, 59.0%, and 67.1% for the SRS-only cohort, respectively; subhazard ratio 0.961, p = 0.896) of AVM obliteration were similar between the matched cohorts. The secondary outcomes of the matched cohorts were also similar. Asymptomatic and symptomatic embolization-related complication rates in the matched OE+SRS cohort were 18.9% and 9.4%, respectively. CONCLUSIONS Pre-SRS AVM embolization with Onyx does not appear to negatively influence outcomes after SRS. These analyses, based on de novo nidal characteristics, thereby refute previous studies that found detrimental effects of Onyx embolization on SRS-induced AVM obliteration. However, given the risks incurred by nidal embolization using Onyx, this neoadjuvant intervention should be used judiciously in multimodal treatment strategies involving SRS for appropriately selected large-volume or angioarchitecturally high-risk AVMs.

Published
2021

95. Hemorrhage and Recurrence of Obliterated Brain Arteriovenous Malformations Treated With Stereotactic Radiosurgery

Author

Ching-Jen, Chen, Dale, Ding, Jeyan S, Kumar, Kathryn N, Kearns, Natasha, Ironside, Huai-Che, Yang, Akiyoshi, Ogino, Hideyuki, Kano, Roman, Liscak, Jaromir, May, Brian J, Williams, Michael J, Gigliotti, Kevin, Cockroft, James, McInerney, Scott, Simon, Cheng-Chia, Lee, and Jason P, Sheehan

Subjects
Intracranial Arteriovenous Malformations, Advanced and Specialized Nursing, Treatment Outcome, Brain, Humans, Neurology (clinical), Child, Radiosurgery, Cardiology and Cardiovascular Medicine, Intracranial Hemorrhages, Follow-Up Studies, Retrospective Studies
Abstract

Background: Although complete nidal obliteration of brain arteriovenous malformations (AVM) is generally presumed to represent durable cure, postobliteration hemorrhage, and AVM recurrence have become increasingly recognized phenomena. The goal of the study was to define hemorrhage and nidal recurrence risks of obliterated AVMs treated with stereotactic radiosurgery (SRS). Methods: This is a retrospective cohort study from the International Radiosurgery Research Foundation comprising AVM patients treated between 1987 and 2020. Patients with AVM obliteration on digital subtraction angiography (DSA) were included. Outcomes were (1) hemorrhage and (2) AVM recurrence. Follow-up duration began at the time of AVM obliteration and was censored at subsequent hemorrhage, AVM recurrence, additional AVM treatment, or loss to follow-up. Annualized risk and survival analyses were performed. A sensitivity analysis comprising patients with AVM obliteration on magnetic resonance imaging or DSA was also performed for postobliteration hemorrhage. Results: The study cohort comprised 1632 SRS-treated patients with AVM obliteration on DSA. Pediatric patients comprised 15% of the cohort, and 42% of AVMs were previously ruptured. The mean imaging follow-up after AVM obliteration was 22 months. Among 1607 patients with DSA-confirmed AVM obliteration, 16 hemorrhages (1.0%) occurred over 2223 patient-years of follow-up (0.72%/y). Of the 1543 patients with DSA-confirmed AVM obliteration, 5 AVM recurrences (0.32%) occurred over 2071 patient-years of follow-up (0.24%/y). Of the 16 patients with postobliteration hemorrhage, AVM recurrence was identified in 2 (12.5%). In the sensitivity analysis comprising 1939 patients with post-SRS AVM obliteration on magnetic resonance imaging or DSA, 16 hemorrhages (0.83%) occurred over 2560 patient-years of follow-up (0.63%/y). Conclusions: Intracranial hemorrhage and recurrent arteriovenous shunting after complete nidal obliteration are rare in AVM patients treated with SRS, and each phenomenon harbors an annual risk of

Published
2022

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