No description available.

Abstract Intracerebral hemorrhage (ICH) is the most pernicious form of stroke, with high mortality. Warfarin-associated ICH (WA-ICH) carries an even higher mortality rate. The major reason for the high mortality is explained by early hematoma growth. Warfarin use has rapidly increased with the aging of the population. We investigated temporal trends in the incidence and outcome of WA-ICHs. We found that although the proportion of warfarin users almost quadrupled in our population, the annual incidence and case fatality of WA-ICHs decreased. Management of ICH is mostly supportive. Prevention of associated complications is the issue in improving outcome. Hypertension is the most important modifiable risk factor for primary ICH, but little is known of the effect of preceding hypertension on outcome. Aggressive lowering of blood pressure is suggested to be a feasible treatment option. Reversal of warfarin anticoagulation with prothrombin complex concentrate (PCC) has been implemented as an acute treatment option for patients with WA-ICH. We found that the survival of WA-ICH subjects among our population improved after implementation of reversal of warfarin anticoagulation with PCC, likely because of the introduction of PCC. Because high mean arterial blood pressure (BP) at admission is an independent predictor of early death in patients with ICH, we explored its role in survival and poor outcome separately in normotensive subjects and subjects with treated and untreated hypertension. We found that despite their higher BP values at admission, subjects with untreated hypertension showed better survival and more often a favorable outcome after BP-lowering therapy than other patients. Studies on recurrent ICH are scarce. Underlying comorbidities, prior strokes, and drug-induced impaired platelet function may increase the risk for primary ICH (PICH). A lobar location of primary ICH may predict recurrent ICH. We investigated whether these factors predicted recurrence of PICH. In our study the annual incidence of recurrent ICH was 1.67%. Cumulative 5- and 10-year incidences were 9.6% and 14.2%. In multivariable analyses, prior ischemic stroke and diabetes proved to be independent predictors for recurrence. Moreover, diabetes was an independent risk factor for fatal recurrent PICH. Use of aspirin and serotonergic drugs did not significantly contribute to the risk. / Tiivistelmä Aivoverenvuoto (ICH) on aivoverenkiertohäiriöistä vakavin. Sille on tyypillistä korkea kuolleisuus erityisesti varfariinihoitoon liittyen, ja eloonjääneetkin vammautuvat usein vakavasti. Verenvuodon koon kasvu alkuvaiheessa selittänee korkean kuolleisuuden. Väestön ikääntymisen myötä varfariinin käyttö on lisääntynyt nopeasti. Aivoverenvuodon hoito perustuu pitkälti ennusteen parantamiseen komplikaatioita estämällä. Verenpaine on tärkein hoidettavissa oleva riskitekijä, mutta tutkimustieto akuutin vaiheen verenpainetason merkityksestä ennusteeseen on vähäistä. Tehokasta verenpaineen alentamista alkuvaiheessa pidetään lupaavana hoitomenetelmänä. Vuodon koon kasvua pyritään rajoittamaan kumoamalla varfariinin antikoaguloiva vaikutus protrombiinikompleksi-konsentraatilla (PCC). Väitöstyössäni selvitän varfariinin käyttöön liittyvien aivoverenvuotojen (WA-ICH) esiintymistiheyttä ja ennustetta ajan myötä. Tutkin myös vuodon koon kasvun rajoittamista ja alkuvaiheen korkean verenpaineen alentamista hoitomenetelminä sekä selvitän, mitkä tekijät johtavat ICH:n uusiutumiseen. Totesimme WA-ICH:n ilmaantuvuuden ja tapauskuolleisuuden pienentyneen, vaikka varfariinin käyttö miltei nelinkertaistui väestössämme. Toisaalta WA-ICH -potilaiden kuolleisuus pieneni PCC-hoidon aloittamisen jälkeen, mahdollisesti sen ansiosta. Tutkiessamme riippumattomasti varhaista kuolemaa ennustavan korkean tulovaiheen verenpaineen roolia normaaliverenpaineisilla, hoidettua ja hoitamatonta verenpainetautia sairastavilla totesimme hoitamattomien hypertonia-potilaiden selvinneen akuutin vaiheen lääkehoidon myötä muita useammin hengissä ja hyväkuntoisina korkeista tulovaiheen verenpainearvoista huolimatta. Aivoverenvuodon uusiutumiseen vaikuttavista tekijöistä on vähän tutkimustietoa. Muu sairastavuus, aiemmat aivoverenkiertohäiriöt ja trombosyyttien toimintaan vaikuttavat lääkkeet saattavat lisätä ICH:n uusiutumisriskiä. Totesimme vuosittaisen uuden ICH:n esiintymistiheyden olevan 1,67 %. Aikaisempi aivoinfarkti ja diabetes osoittautuivat riippumattomiksi uusiutumista ennustaviksi riskitekijöiksi, minkä lisäksi diabetes ennusti kuolemaan johtavaa uutta ICH:a. Asetyylisalisyylihapon ja selektiivisten serotoniinin takaisinoton estäjien käyttäminen ei vaikuttanut merkittävästi uusiutumisriskiin.

Background Many risk factors for stroke are well characterized and might, at least to some extent, be similar for first-ever stroke and for recurrent stroke events. However, previous studies have shown heterogeneous results on predictors and rates of stroke recurrence. Patients who survive spontaneous intracerebral hemorrhage (ICH) often have compelling indications for antithrombotic (AT) treatment (antiplatelet (AP) and/or anticoagulant (AC) treatment), but due to controversy of the decision to treat, a large proportion of these patients are untreated. In the absence of evidence from randomized controlled trials (RCTs), there is need for more high- quality observational data on the clinical impact of, and optimal timing of AT in ICH survivors. The aims of this thesis were to assess time trends in stroke recurrence, to determine the factors associated with an increased risk of stroke recurrence – including socioeconomic factors – and to determine to what extent ICH survivors with and without atrial fibrillation (AF) receive AT treatment and to determine the optimal timing (if any) of such treatment.  Methods The population-based Monitoring Trends and Determinants of Cardiovascular Disease (MONICA) stroke incidence register was used to assess the epidemiology and predictors of stroke recurrence after ischemic stroke (IS) and ICH from 1995 to 2008 in northern Sweden. Riksstroke, the Swedish stroke register, linked with the National Patient Register and the Swedish Dispensed Drug Register, made it possible to identify survivors of first-ever ICH from 2005 to 2012 with and without concomitant AF to investigate to what extent these patients were prescribed AP and AC therapy. The optimal timing of initiating treatment following ICH in patients with AF 2005–2012 was described through separate cumulative incidence functions for severe thrombotic and hemorrhagic events and for the combined endpoint “vascular death or non-fatal stroke”. Riksstroke data on first-ever stroke patients from 2001 to 2012 was linked to the Longitudinal Integration Database for Health Insurance and Labour market studies to add information on education and income to investigate the relationship between socioeconomic status and risk of recurrence. Results Comparison between the cohorts of 1995–1998 and 2004–2008 showed declining risk of stroke recurrence (hazard ratio: 0.64, 95% confidence interval (CI): 0.52-0.78) in northern Sweden. Significant factors associated with an increased risk of stroke recurrence were age and diabetes. Following ICH, a majority (62%) of recurrent stroke events were ischemic.  The nationwide Riksstroke study confirmed the declining incidence, and it further concluded that low income, primary school as highest attained level of education, and living alone were associated with a higher risk of recurrence beyond the acute phase. The inverse effects of socioeconomic status on risk of recurrence did not differ between men and women and persisted over the study period. Of Swedish ICH-survivors with AF, 8.5% were prescribed AC and 36.6% AP treatment, within 6 months of ICH. In patients with AF, predictors of AC treatment were less severe ICH, younger age, previous anticoagulation, valvular disease and previous IS. High CHA2DS2-VASc scores did not seem to correlate with AC treatment. We observed both an increasing proportion of AC treatment at time of the initial ICH (8.1% in 2006 compared with 14.6% in 2012) and a secular trend of increasing AC use one year after discharge (8.3% in 2006 versus 17.2% in 2011) (p<0.001 assuming linear trends). In patients with high cardiovascular event risk, AC treatment was associated with a reduced risk of vascular death and non-fatal stroke with no significantly increased risk of severe hemorrhage. The benefit appeared to be greatest when treatment was started 7–8 weeks after ICH. For high-risk women, the total risk of vascular death or stroke recurrence within three years was 17.0% when AC treatment was initiated eight weeks after ICH and 28.6% without any antithrombotic treatment (95% CI for difference: 1.4% to 21.8%). For high-risk men, the corresponding risks were 14.3% vs. 23.6% (95% CI for difference: 0.4% to 18.2%). Conclusion Stroke recurrence is declining in Sweden, but it is still common among stroke survivors and has a severe impact on patient morbidity and mortality. Age, diabetes and low socioeconomic status are predictors of stroke recurrence. Regarding ICH survivors with concomitant AF, physicians face the clinical dilemma of balancing the risks of thrombosis and bleeding. In awaiting evidence from RCTs, our results show that AC treatment in ICH survivors with AF was initiated more frequently over the study period, which seems beneficial, particularly in high-risk patients. The optimal timing of anticoagulation following ICH in AF patients seems to be around 7–8 weeks following the hemorrhage.

No description available.

MSc (Statistics) / Department of Mathematics and Natural Sciences

Orientador: Laís Helena Navarro e Lima / Resumo: Introdução: A triagem e avaliação inicial de pacientes com hipovolemia são guiadas pela apresentação dos sintomas clínicos e pelas alterações nos sinais vitais. Frequência cardíaca (FC) e pressão arterial sistólica (PAS), isoladamente, nem sempre refletem com acurácia o início de quadros hipovolêmicos. Contudo, a combinação dos sinais vitais tradicionais (FC/PAS) origina o índice de choque (IC), que se postula ser indicador mais precoce de hipovolemia. Objetivo: A proposta deste estudo foi estabelecer a acurácia diagnóstica do IC para o diagnóstico inicial de hipovolemia decorrente de hemorragia, tanto em ambiente simulado, quanto em situações clínicas obstétricas. Método: Estudos transversais que incluíram dados de indivíduos adultos de qualquer idade ou sexo com suspeita de hemorragia, provenientes de estudos clínicos (obstétricos) ou simulados (doadores de sangue ou submetidos à LBNP – Low body negative pressure), que avaliaram a acurácia do IC e dos sinais vitais tradicionais (PA e FC) isolados no diagnóstico de hipovolemia foram incluídos no presente estudo. Valores considerados como hipovolêmicos foram IC > 0,7, FC > 100 bpm e/ou PAS < 100 mmHg. Obtiveram-se os estudos das seguintes bases de dados: CENTRAL, MEDLINE, EMBASE e LILACS, com os termos “shock index” e “hypovolemia” e suas variantes. Última pesquisa foi realizada em maio de 2016. A ferramenta QUADAS avaliou a qualidade metodológica. Metanálise proporcional foi realizada com variáveis dicotômicas e seus respect... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

<p>Simulation modeling has proven beneficial in gathering insights that may aid safety policy considerations for schools, offices, and outdoor events. This is especially true when conducting a drill that is not practical or possible, such as active shooter response. However, we can improve the current modeling practices with high-fidelity simulation logic reflecting a victim's well-being. Currently, victims are modeled either as “killed,” or they continue their normal movement. The binary approach is suitable for many simulations developed to understand course trends in an event space but does not allow for more fine-tuned insights that may be beneficial when developing a safety and response protocol for a specific facility or event. Additional victim characteristics, such as tracking the location of a victim's wound and the rate of physiological decline, may be added into a model that will improve the realism and lead to an improved response protocol. The increased fidelity will be helpful when simulating and assessing the effects of volunteer response, critical care transport for medical intervention, and other first-responder interventions.</p> <p>While some think it is not possible or necessary to simulate how fast gunshot victims would lose blood, we show that a high-fidelity simulation is possible. The main counterargument is that there is no sufficient data, and also it will be challenging to implement this process as it is occurring. However, we found enough data or were able to extrapolate the missing pieces and develop a consistent and realistic blood loss model. In addition, the state of current simulation packages, such as AnyLogic, has advanced to the point where we can model a liquid system dynamic within an agent-based model. Furthermore, there is an acute benefit to conducting this type of research as it can help us develop better response policies, which result in more saved lives.</p> <p>The research aims to improve emergency-response simulation fidelity by developing a model that simulates gunshot wounds and the subsequent blood loss while accounting for a victim's age, weight, gender, and the affected area. The model also accounts for the body's compensatory response and medical interventions, such as tourniquet application, wound packing, and direct pressure. The work presents an analytical model and its implementation using agent-based modeling in AnyLogic. This AnyLogic module can be inserted into active shooter simulations that easily integrate with the existing logic. This integration happens through a high-level application programming interface (API) exposed to the user. The API allows for automatic infliction of injury and mitigation. The extensive literature review and case studies provide a sound foundation for creating the model. AnyLogic was chosen due to its common usage and versatility with other systems and computer programming languages.</p>

This study investigated possible solutions to the current wartime problem of junctional hemorrhaging, or massive traumatic hemorrhaging in non-tourinquetable areas such as the neck, groin, or armpit. Junctional hemorrhaging has been identified as a major contributor to potentially survivable deaths seen on the battlefield today and therefore is a priority for the U.S. armed and coalition forces (Kragh et al., 2011a; Bozeman, 2011). Common tourniquets today are standard issue and carried by soldiers in the military, but are limited to distal extremity trauma. As the battlefield has changes however, trauma has transformed from commonly seen gunshot wounds to more extreme trauma such as dismounted complex blast injuries which typically includes loss of one or more appendages. These newly found situations render the traditional tourniquet ineffective. Thus, the development of a new tourniquet to control hemorrhaging from regions such as the neck, armpit, and groin has been deemed necessary. The development of a new tourniquet for hemorrhage control included market research, preliminary testing to determine design restraints, design ideation, finite element analysis, manufacturing a prototype, and prototype testing. Research and comparisons were done of the strengths and weaknesses of tourniquets already approved by the Food and Drug Administration (FDA). Next, design limitations were found using preliminary testing on a blood-flow replicate model developed by Tracey Cheung. The results from this testing provided a framework for designing a new tourniquet. A new approach to control junction hemorrhaging was then designed, built, and tested on the Cheung model. To verify the design, simplified models were analyzed using finite element analysis. The prototype was then tested and compared against the FDA approved tourniquets, listing the advantages and possible shortcomings.

Background: Cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) has been extensively investigated, but the impact of collateralization remains unclear. We investigated the predictive value of collateral activation for delayed cerebral ischemia (DCI)-related infarctions and functional outcome. Methods: Data from 43 patients with CVS (January 2014 to August 2021) were evaluated for the angiographic presence of leptomeningeal and ophthalmic collaterals (anterior falcine artery (AFA), supratrochlear artery (STA), dorsal nasal artery (DNA)) on internal carotid artery angiograms. Vasospasm-related infarction and the modified Rankin Scale (mRS) score after six months were chosen as the endpoints. Results: 77% of the patients suffered from DCI-related infarctions. In 233 angiograms (at hospitalization, before spasmolysis, after six months), positive vessel signs were observed in 31 patients for STA, 35 for DNA, and 31 for AFA. The STA sign had the highest positive (84.6%) and negative (85.7%) predictive value for unfavorable outcome (mRS 4–6) in patients aged 50 years. DNA and AFA signs were not meaningful predictors for either endpoint. Leptomeningeal collaterals showed a positive Pearson’s correlation with the STA sign in 87.5% (p = 0.038) without providing any prediction for either endpoint. Conclusions: The STA sign is associated with clinical outcome in patients with CVS after SAH aged 50 years, and was correlated with the occurrence of leptomeningeal collaterals.

Background: Cerebral vasospasm (CVS) continues to account for high morbidity and mortality in patients surviving the initial aneurysmal subarachnoid hemorrhage (SAH). Nimodipine is the only drug known to reduce delayed cerebral ischemia (DCI), but it is believed not to affect large vessel CVS. Milrinone has emerged as a promising option. Our retrospective study focused on the effectiveness of the intra-arterial application of both drugs in monotherapy and combined therapy. Methods: We searched for patients with aneurysmal SAH, angiographically confirmed CVS, and at least one intra-arterial pharmacological angioplasty. Ten defined vessel sections on angiograms were assessed before and after vasodilator infusion. The improvement in vessel diameters was compared to the frequency of DCI-related cerebral infarction before hospital discharge and functional outcome reported as the modified Rankin Scale (mRS) score after 6 months. Results: Between 2014 and 2021, 132 intra-arterial interventions (144 vascular territories, 12 bilaterally) in 30 patients were analyzed for this study. The vasodilating effect of nimodipine was superior to milrinone in all intradural segments. There was no significant intergroup difference concerning outcome in mRS (p = 0.217). Only nimodipine or the combined approach could prevent DCI-related infarction (both 57.1%), not milrinone alone (87.5%). Both drugs induced a doubled vasopressor demand due to blood pressure decrease, but milrinone alone induced tachycardia. Conclusions: The monotherapy with intra-arterial nimodipine was superior to milrinone. Nimodipine and milrinone may be used complementary in an escalation scheme with the administration of nimodipine first, complemented by milrinone in cases of severe CVS. Milrinone monotherapy is not recommended.