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| 2. |
- Coutinho, Jonathan M., et al.
(author)
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Reducing the global burden of cerebral venous thrombosis: An international research agenda
- 2024
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In: INTERNATIONAL JOURNAL OF STROKE. - 1747-4930 .- 1747-4949.
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Research review (peer-reviewed)abstract
- Background: Due to the rarity of cerebral venous thrombosis (CVT), performing high-quality scientific research in this field is challenging. Providing answers to unresolved research questions will improve prevention, diagnosis, and treatment, and ultimately translate to a better outcome of patients with CVT. We present an international research agenda, in which the most important research questions in the field of CVT are prioritized.Aims: This research agenda has three distinct goals: (1) to provide inspiration and focus to research on CVT for the coming years, (2) to reinforce international collaboration, and (3) to facilitate the acquisition of research funding.Summary of review: This international research agenda is the result of a research summit organized by the International Cerebral Venous Thrombosis Consortium in Amsterdam, the Netherlands, in June 2023. The summit brought together 45 participants from 15 countries including clinical researchers from various disciplines, patients who previously suffered from CVT, and delegates from industry and non-profit funding organizations. The research agenda is categorized into six pre-specified themes: (1) epidemiology and clinical features, (2) life after CVT, (3) neuroimaging and diagnosis, (4) pathophysiology, (5) medical treatment, and (6) endovascular treatment. For each theme, we present two to four research questions, followed by a brief substantiation per question. The research questions were prioritized by the participants of the summit through consensus discussion.Conclusions: This international research agenda provides an overview of the most burning research questions on CVT. Answering these questions will advance our understanding and management of CVT, which will ultimately lead to improved outcomes for CVT patients worldwide.
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| 3. |
- Hynd, Ryan, et al.
(author)
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Decay of extremals of Morrey’s inequality
- 2024
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In: Arkiv för matematik. - : International Press, Inc.. - 0004-2080 .- 1871-2487. ; 62:1, s. 73-81
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Journal article (peer-reviewed)abstract
- We study the decay (at infinity) of extremals of Morrey’s inequality in Rn. These are functions satisfying (Formula Presented) where p>n and C(p, n) is the optimal constant in Morrey’s inequality. We prove that if n≥2 then any extremal has a power decay of order β for any (Formula Presented).
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| 4. |
- Klein, Piers, et al.
(author)
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External validation of the SI2NCAL2C score for outcomes following cerebral venous thrombosis
- 2024
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In: JOURNAL OF STROKE & CEREBROVASCULAR DISEASES. - 1052-3057 .- 1532-8511. ; 33:6
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Journal article (peer-reviewed)abstract
- Objectives: Prognostication for cerebral venous thrombosis (CVT) remains difficult. We sought to validate the SI2NCAL2C 2 NCAL 2 C score in an international cohort. Materials and methods: The SI2NCAL2C 2 NCAL 2 C score was originally developed to predict poor outcome (modified Rankin Scale (mRS) 3-6) at 6 months, and mortality at 30 days and 1 year using data from the International CVT Consortium. The SI2NCAL2C 2 NCAL 2 C score uses 9 variables: the absence of any female-sex-specific risk factors,intracerebral hemorrhage, central nervous system infection, focal neurological deficits, coma, age, lower level of hemoglobin, higher level of glucose, and cancer. The ACTION-CVT study was an international retrospective study that enrolled consecutive patients across 27 centers. The poor outcome score was validated using 90-day mRS due to lack of follow-up at the 6-month time-point in the ACTION-CVT cohort. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC) and calibration plots. Missing data were imputed using the additive regression and predictive mean matching methods. Bootstrapping was performed with 1000 iterations. Results: Mortality data were available for 950 patients and poor outcome data were available for 587 of 1,025 patients enrolled in ACTION-CVT. Compared to the International CVT Consortium, the ACTION-CVT cohort was older, less often female, and with milder clinical presentation. Mortality was 2.5% by 30 days and 6.0% by one year. At 90-days, 16.7% had a poor outcome. The SI2NCAL2C 2 NCAL 2 C score had an AUC of 0.74 [95% CI 0.69-0.79] for 90-day poor outcome, 0.72 [0.60-0.82] for mortality by 30 days, and 0.82 [0.76-0.88] for mortality by one year. Conclusions: The SI2NCAL2C 2 NCAL 2 C score had acceptable to good performance in an international external validation cohort. The SI2NCAL2C 2 NCAL 2 C score warrants additional validation studies in diverse populations and clinical implementation studies.
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| 5. |
- Lennborn, Ulrica, et al.
(author)
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Recommended dosages of analgesic and sedative drugs in intensive care result in a low incidence of potentially toxic blood concentrations
- 2024
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In: Upsala Journal of Medical Sciences. - : Upsala Medical Society. - 0300-9734 .- 2000-1967. ; 129
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Journal article (peer-reviewed)abstract
- Background: Standard dosages of analgesic and sedative drugs are given to intensive care patients. The resulting range of blood concentrations and corresponding clinical responses need to be better examined. The purpose of this study was to describe daily dosages, measured blood concentrations, and clinical responses in critically ill patients. The purpose was also to contribute to establishing whole blood concentration reference values of the drugs investigated.Methods: A descriptive study of prospectively collected data from 302 admissions to a general intensive care unit (ICU) at a university hospital. Ten drugs (clonidine, fentanyl, morphine, dexmedetomidine, ketamine, ketobemidone, midazolam, paracetamol, propofol, and thiopental) were investigated, and daily dosages recorded. Blood samples were collected twice daily, and drug concentrations were measured. Clinical responses were registered using Richmond agitation-sedation scale (RASS) and Numeric rating scale (NRS).Results: Drug dosages were within recommended dose ranges. Blood concentrations for all 10 drugs showed a wide variation within the cohort, but only 3% were above therapeutic interval where clonidine (57 of 122) and midazolam (38 of 122) dominated. RASS and NRS were not correlated to drug concentrations.Conclusion: Using recommended dose intervals for analgesic and sedative drugs in the ICU setting combined with regular monitoring of clinical responses such as RASS and NRS leads to 97% of concentrations being below the upper limit in the therapeutic interval. This study contributes to whole blood drug concentration reference values regarding these 10 drugs.
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| 6. |
- Ranjan, Redoy, et al.
(author)
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Coma in adult cerebral venous thrombosis: The BEAST study
- 2024
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In: EUROPEAN JOURNAL OF NEUROLOGY. - 1351-5101 .- 1468-1331. ; 31:8
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Journal article (peer-reviewed)abstract
- Background and purpose: Coma is an independent predictor of poor clinical outcomes in cerebral venous thrombosis (CVT). We aimed to describe the association of age, sex, and radiological characteristics of adult coma patients with CVT. Methods: We used data from the international, multicentre prospective observational BEAST (Biorepository to Establish the Aetiology of Sinovenous Thrombosis) study. Only positively associated variables with coma with <10% missing data in univariate analysis were considered for the multivariate logistic regression model. Results: Of the 596 adult patients with CVT (75.7% women), 53 (8.9%) patients suffered coma. Despite being a female-predominant disease, the prevalence of coma was higher among men than women (13.1% vs. 7.5%, p = 0.04). Transverse sinus thrombosis was least likely to be associated with coma (23.9% vs. 73.3%, p < 0.001). The prevalence of superior sagittal sinus thrombosis was higher among men than women in the coma sample (73.6% vs. 37.5%, p = 0.01). Men were significantly older than women, with a median (interquartile range) age of 51 (38.5-60) versus 40 (33-47) years in the coma (p = 0.04) and 44.5 (34-58) versus 37 (29-48) years in the non-coma sample (p < 0.001), respectively. Furthermore, an age- and superior sagittal sinus-adjusted multivariate logistic regression model found male sex (odds ratio = 1.8, 95% confidence interval [CI] = 1.0-3.4, p = 0.04) to be an independent predictor of coma in CVT, with an area under the receiver operating characteristic curve of 0.61 (95% CI = 0.52-0.68, p = 0.01). Conclusions: Although CVT is a female-predominant disease, men were older and nearly twice as likely to suffer from coma than women.
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| 7. |
- Sahl, Mikael
(author)
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Ultrasonic testing of components produced with additive manufacturing : Towards improved detection and classification of defects
- 2024
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Licentiate thesis (other academic/artistic)abstract
- The focus in this work is on the use of ultrasonic testing as a method for inspecting components manufactured through additive manufacturing (AM) processes. The research is rooted in the need for effective non-destructive testingtechniques that can adapt to the unique challenges posed by AM-produced materials, including complex defect geometries and surface conditions.Ultrasonic testing is a versatile form of non-destructive testing, offering theability to detect internal flaws, such as voids, cracks, and inclusions, with highprecision and in real-time. Unlike many competing methods, ultrasonic testing works on most types of materials. Ultrasonic testing has been applied forinspection purposes for a long time. Now with emerging manufacturing methods, there is a need for evaluation techniques to keep up with this development.New data processing algorithms open up possibilities of extracting more information from the acquired signal.The thesis provides a review of UT’s capabilities in detecting and classifyingdefects within AM components, with a particular emphasis on the subtletiesintroduced by the layer-by-layer construction method inherent to AM technologies. The work advances development and validation of simulation modelsaimed at predicting the ultrasonic response from manufactured defects. Thesemodels are crucial for understanding the interaction between ultrasound wavesand material anomalies, offering insights into the potential for enhanced defectdetection strategies.The research also explores the practical case of integrating UT into the quality assurance processes by relying on mathematical simulation rather than experimental data. The findings suggest avenues for the refinement of creation of inspection procedure, including the the use of meta-models to cheaply acquire worst-case scenario defects, to better accommodate the specificities of AM materials.
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| 8. |
- Scutelnic, Adrian, et al.
(author)
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Characteristics and outcomes of cerebral venous thrombosis associated with COVID-19
- 2024
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In: EUROPEAN STROKE JOURNAL. - 2396-9873 .- 2396-9881.
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Journal article (peer-reviewed)abstract
- Introduction: Previous reports and meta-analyses derived from small case series reported a mortality rate of up to 40% in patients with coronavirus disease 2019 associated cerebral venous thrombosis (COVID-CVT). We assessed the clinical characteristics and outcomes in an international cohort of patients with COVID-CVT. Patients and methods: This was a registry study of consecutive COVID-CVT patients diagnosed between March 2020 and March 2023. Data collected by the International Cerebral Venous Thrombosis Consortium from patients with CVT diagnosed between 2017 and 2018 served as a comparison. Outcome analyses were adjusted for age and sex. Results: We included 70 patients with COVID-CVT from 23 hospitals in 15 countries and 206 controls from 14 hospitals in 13 countries. The proportion of women was smaller in the COVID-CVT group (50% vs 68%, p < 0.01). A higher proportion of COVID-CVT patients presented with altered mental state (44% vs 25%, p < 0.01), the median thrombus load was higher in COVID-CVT patients (3 [IQR 2-4] vs 2 [1-3], p < 0.01) and the length of hospital stay was longer compared to controls (11 days [IQR 7-20] vs 8 [4-15], p = 0.02). In-hospital mortality did not differ (5/67 [7%, 95% CI 3-16] vs 7/206 [3%, 2-7], aOR 2.6 [95% CI 0.7-9]), nor did the frequency of functional independence after 6 months (modified Rankin Scale 0-2; 45/58 [78%, 95% CI 65-86] vs 161/185 [87%, 81-91], aOR 0.5 [95% CI 0.2-1.02]). Conclusion: In contrast to previous studies, the in-hospital mortality rate and functional outcomes during follow-up did not differ between COVID-CVT patients and the pre-COVID-19 controls.
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| 9. |
- Thalavai Pandian, Karthikeyan, 1985-, et al.
(author)
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Characterization of surface asperities to understand its effect on fatigue life of electron beam powder bed fusion manufactured Ti-6Al-4 V
- 2024
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In: International Journal of Fatigue. - : Elsevier. - 0142-1123 .- 1879-3452. ; 188
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Journal article (peer-reviewed)abstract
- Surface asperities play a leading role in determining the fatigue life of as-built Ti-6Al-4 V components manufactured by electron beam powder bed fusion (PBF-EB). Several roughness parameters are available to characterize the surface asperities This study focuses on identifying the surface roughness parameter that correlates best with fatigue life. To this end, several fatigue test specimens were manufactured using the PBF-EB process and utilizing different contour melting strategies, thus producing as-built surfaces with varying roughness. The focus variation microscopy technique was employed to obtain surface roughness parameters for the as-built surfaces. Selected specimens were characterized using x-ray computed tomography (XCT). Tomography can detect surface-connected features obscured by other parts of the surface that are not visible through optical microscopy. The fatigue life of all specimens was determined using four-point bend testing. Through regression model analysis, maximum pit height (Sv) was identified as the statistically significant roughness parameter with the best fit affecting fatigue life. The fracture zone was closely inspected based on the data collected through XCT prior to fatigue tests. This led to another estimate of the worst-case value for the statistically significant roughness parameter Sv. The Sv parameter values obtained from optical microscopy and XCT were used as the initial crack size in a crack growth model to predict fatigue life. It is observed that life estimates based solely on optical measurements of Sv can be overly optimistic, a situation that must be avoided in predictive design calculations.
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| 10. |
- Weller, Johannes, et al.
(author)
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Endovascular treatment of cerebral sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia
- 2024
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In: EUROPEAN STROKE JOURNAL. - 2396-9873 .- 2396-9881. ; 9:1, s. 105-113
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Journal article (peer-reviewed)abstract
- Introduction: There is little data on the role of endovascular treatment (EVT) of cerebral venous sinus thrombosis (CVST) due to vaccine-induced immune thrombotic thrombocytopenia (VITT). Here, we describe clinical characteristics and outcomes of CVST-VITT patients who were treated with EVT. Patients and methods: We report data from an international registry of patients who developed CVST within 28 days of SARS-CoV-2 vaccination, reported between 29 March 2021 and 6 March 2023. VITT was defined according to the Pavord criteria. Results: EVT was performed in 18/136 (13%) patients with CVST-VITT (92% aspiration and/or stent retrieval, 8% local thrombolysis). Most common indications were extensive thrombosis and clinical or radiological deterioration. Compared to non-EVT patients, those receiving EVT had a higher median thrombus load (4.5 vs 3). Following EVT, local blood flow was improved in 83% (10/12, 95% confidence interval [CI] 54-96). One (6%) asymptomatic sinus perforation occurred. Eight (44%) patients treated with EVT also underwent decompressive surgery. Mortality was 50% (9/18, 95% CI 29-71) and 88% (8/9, 95% CI 25-66) of surviving EVT patients achieved functional independence with a modified Rankin Scale score of 0-2 at follow-up. In multivariable analysis, EVT was not associated with increased mortality (adjusted odds ratio, 0.66, 95% CI 0.16-2.58). Discussion and conclusion: We describe the largest cohort of CVST-VITT patients receiving EVT. Half of the patients receiving EVT died during hospital admission, but most survivors achieved functional independence.
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