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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Efficacy and safety of warfarin treatment in venous thromboembolic disease

Sandén, Per January 2017 (has links)
Background As a major cause of morbidity and mortality treatment of venous thromboembolism is important, with the correct use of anticoagulants it is possible to greatly reduce both mortality and morbidity. Warfarin is among the most widely used anticoagulants being effective in treatment and prevention of venous thromboembolism with few negative side effects other than bleeding complications. With a narrow therapeutic window warfarin treatment requires constant monitoring and adjustments to stay effective without an increased bleeding risk. The aim of this thesis was to study the efficacy and safety of warfarin treatment in venous thromboembolic disease. Methods Using AuriculA, the Swedish national quality register for atrial fibrillation and anticoagulation, a cohort was created of patients registered with warfarin treatment during the study time January 1st 2006 to December 31th 2011, including all different indications for anticoagulation. In all four studies the study design was retrospective with information added to the cohort from the Swedish national patient register about background data and endpoints in form of bleeding complications in all studies and thromboembolic events in study 1 and 2. In study 3 and 4 information was added from the cause of death register about occurrence of death and in study 3 cause of death. In study 3, information from the prescribed drugs register about retrieved prescriptions of acetylsalicylic acid was added. Results In study 1 the mean TTR was found to be high both among patients managed at primary healthcare centres and specialised anticoagulation clinics at 79.6% and 75.7%. There was no significant difference in rate of bleeding between the two types of managing centres being 2.22 and 2.26 per 100 treatment years. In study 2 no reduction in complication rate with increasing centre TTR was seen for patients with atrial fibrillation with few centres having centre TTR below 70% (2.9%), in contrast to previous findings by Wan et al(1). For those with warfarin due to VTE where a larger proportion of the centres had centre TTR below 70% (9.1%) there was a reduction in complication rate with increasing centre TTR. Among the 13859 patients with treatment for VTE in study 3 age (HR 1.02, CI 95% 1.01-1.03), hypertension (HR 1.29, CI 95%1.02-1.64), Cardiac failure (HR 1.55, CI 95% 1.13-2.11), chronic obstructive pulmonary disease (HR 1.43, CI 95% 1.04- 1.96), alcohol abuse (HR 3.35, CI 95% 1.97-5.71), anaemia (HR 1.77, CI 95% 1.29-2.44) and a history of major bleeding (HR 1.75, CI 95% 1.27-2.42) increased the risk of bleeding during warfarin treatment. In study 4 both those with high iTTR and those with low INR variability had a low rate of bleedings at 1.27 (1.14-1.41) or 1.20 (0.94-1.21) per 100 treatment years compared to those with low iTTR and high INR variability having a rate of bleeding at 2.91 (2.61-3.21) or 2.61 (2.36-2.86) respectively. Those with the combination of both low iTTR and high INR variability had an increased risk of bleeding, hazard ratio HR 3.47 (CI 95 % 2.89-4.17). The quartile with both the lowest iTTR and the highest INR variability had an increased risk of bleeding with a hazard ratio 4.03 (3.20-5.08) and 3.80 (CI 95%, 3.01-4.79) compared to the quartile with the highest iTTR and lowest INR variability. Conclusion It is possible to achieve a safe warfarin treatment both in specialised anticoagulation centres and in primary health care. At initiation of treatment some of the patients at high risk of bleeding can be identified using knowledge about their background. With the use of quality indicators as TTR and INR variability during treatment those at high risk of complications can be identified and analysing treatment quality on centre level gives an opportunity to identify improvement areas among managing centres. With the addition of new treatment options warfarin can still be the most suitable option for some patients, being safe and effective when well managed.
12

Inflammation and cortisol response i coronary artery disease

Nijm, Johnny January 2008 (has links)
Atherosclerosis is characterized by a chronic inflammation, involving autoimmune components, in the arterial wall. An increase in proinflammatory activity relative to anti-inflammatory activity is considered to cause a progression of the disease towards plaque instability and risk of atherothrombotic events, such as acute coronary syndrome (ACS). Cortisol, the end product of the hypothalamus-pituitary-adrenal (HPA) axis, is a powerful endogenous anti-inflammatory mediator. Disturbances in the HPA axis have been reported in chronic inflammatory/autoimmune diseases, like rheumatoid arthritis. The aim of this thesis was to study various markers of systemic inflammation in patients with acute and stable conditions of coronary artery disease (CAD) and relate these findings to the cortisol response. Both patients with ACS and patients with stable CAD had high levels of C-reactive protein (CRP), interleukin (IL)-6 and IL-1 receptor antagonist, compared with healthy controls. In addition, patients with stable CAD had significantly more neutrophil-platelet aggregates than controls, as a possible indicator of neutrophil activation. The cortisol response was determined in two different cohorts of CAD patients; one consisting of patients with a first-time myocardial infarction and one consisting of patients with long-term stable CAD. From the acute phase to 3 months, the patients with a myocardial infarction showed a higher 24-h cortisol secretion and a flattened diurnal slope caused by higher cortisol levels in the evening, as compared with healthy controls. The patients with long-term stable CAD showed similarly high levels of cortisol in the evening. The levels of evening cortisol were strongly correlated with CRP and IL-6. When exposed to acute physical or acute psychological stress at 3 months, the ACS patients showed a markedly blunted cortisol response compared with healthy controls. Following the stress tests, a significant increase in CRP was observed in the patients but not in the controls, indicating a failure of the HPA axis to compensate for stress-induced inflammation in CAD. In the ACS patients, the time course of matrix metalloproteinases (MMPs) and their tissue inhibitor TIMP-1 was determined during the 3 months follow-up. A major finding was that the MMP-9 and TIMP-1 levels remained significantly higher in the patients at all time points compared to the controls. MMP-9 and TIMP-1, but not MMP-2, MMP-3 or MMP-7, were related to inflammatory activity, as assessed by CRP and IL-6. MMP-9 and TIMP-1 showed significant correlation with evening cortisol, even after adjustment for CRP and IL-6, lending further support for a link between ´high´ flat cortisol rhythm and systemic inflammatory activity. The activation status of neutrophils in stable CAD was further examined by measuring the expression, affinity state and signalling capacity of b2-integrins and the innate production of reactive oxygen species (ROS). However, the neutrophils in patients were not more activated in vivo than were cells in healthy controls, neither were they more prone to activation ex vivo. The data rather indicated an impaired function of neutrophils in stable CAD. The neutrophils in CAD patients showed a significantly lower number of total glucocorticoid receptors (GRs) and a lower GRa:GRb ratio compared to healthy controls, indicating a chronic over activation of the HPA axis and, possibly, a state of glucocorticoid resistance. Moreover, the evening cortisol levels in patients were associated with an overexpression of annexin-1, the ´second messenger´ of glucocorticoid action. In contrast to neutrophils in controls, the neutrophils in patients also showed a hyper responsiveness to exogenous annexin-1 resulting in impaired neutrophil function. To conclude, clinically stable CAD was associated with a systemic inflammatory activity, involving a high MMP-9:TIMP-1 ratio and an increased inflammatory response to acute stress but not any activation of neutrophils. This inflammatory activity was associated with a dysregulated cortisol secretion, defined by a flat diurnal rhythm and a blunted cortisol response to stress. Although the clinical relevance remains to be verified, an intriguing hypothesis is that a hyporesponsive HPA axis favours the development towards plaque instability. / On the day of the defence date the title of article III was: "A sustained elevation of serum matrix metalloproteinase-9 is associated with diurnal salivary cortisol in patients with acute myocardial infarction-a 3-month follow-up".
13

Inflammation, platelet aggregation and prognosis in acute myocardial infarction

Modica, Angelo January 2010 (has links)
The incidence of stroke and re-infarction is noticeably high in the first few days following acute myocardial infarction. This finding has raised questions whether the systemic inflammatory reaction secondary to myocardial necrosis is involved. The inflammation might affect the activation of platelets leading to insufficient effect of the antiplatelet treatment given. Furthermore, the importance of platelet reactivity and inflammation in terms of long-term prognosis is not fully understood. The prognostic importance of C-reactive protein (CRP) in relation to clinical variables also needs to be clarified. The present studies are aimed at describing the dynamics of platelet function during the first days of an acute myocardial infarction, in relation to diabetes and inflammation. We also investigated whether increased platelet reactivity or the increased concentration of CRP in blood were related to a worse outcome. Finally, we examined if CRP levels contributed to a predictive model using clinical variables known to affect outcome in patients with AMI.  We used two novel platelet function tests to measure platelet reactivity; the PA-200 (a laser light aggregometer) and the PFA-100 (measures primary haemostasis in whole blood). Platelet aggregation increased during the initial course of an acute myocardial infarction. The increase in platelet aggregation was most pronounced in diabetics and in patients showing higher systemic inflammatory reaction, assessed by measuring the concentration of CRP in blood. The pronounced platelet aggregation occurred despite ongoing antiplatelet and antithrombotic treatment. There was a significant association between the levels of CRP and the degree of platelet reactivity. However, while the CRP levels were associated with a worse outcome (AMI, stroke and death), the results of the platelet function tests were not. The importance of CRP in predicting prognosis depended on which adjustments were made for confounding factors. CRP and prognostic variables in a statistical model predicting death, however, showed that CRP was excluded. Thus CRP did not predict outcome beyond clinical prognostic variables. The results of these studies reinforce the importance of clinical variables such as heart failure, age, atrial fibrillation, smoking status, diabetes and impaired kidney function - all of which were associated with worse prognosis in multivariable analysis.
14

Health economic evaluation of community-based cardiovascular disease prevention : some theoretical aspects and empirical results

Lindholm, Lars January 1996 (has links)
This thesis addresses the health economic evaluation of community-based interventions against cardiovascular disease (CVD), with special emphasis on the Västerbotten Intervention Project (VIP), run since 1985. The framework is a simple evaluation model consisting of two parts; the selection and measurement of empirical consequences caused by the project under evaluation (e.g. changes in mortality, well-being, use of resources) and a set of values (e.g. efficiency, equity) aimed at assessing the goodness of these consequences. The project’s effects on CVD were predicted by means of risk factors measured in Norsjö between 1985-1990, applied to an epidemiological model based on a logistic risk equation derived from the Framingham population. Cost per life-years saved ranged from £14 900 to net savings, depending on the assumptions. The favourable cost-effectiveness in this kind of intervention has earlier been predicted from theoretical models, but this is the first study based on real experiences from contemporary community-based interventions against CVD. Furthermore, all social classes have benefited from the intervention. Also potential adverse effects in the form of excess mortality due to low cholesterol levels were investigated, and they were negligible in comparison with the health gains. The value of an intervention from a citizen’s perspective was investigated through an interview study (n≈100) in accordance with the contingent valuation method. Great expectations concerning mortality effects on the community level and future savings in health care were good predictors for assigning the intervention a high value. On the contrary, personal benefits in the form of a decreasing risk for CVD had no positive association with the value of the intervention. Hence, the consequences that the cost-effectiveness analysis accounts for - mortality and savings - coincide with the most valuable consequences from the citizen's perspective. In a democracy, the set of values used to determine the success or failure of a programme like a prevention project must agree with values held by the majority of the citizens. Therefore, the attitudes to ethical values among Swedish politicians (n≈450) responsible for health care have been mapped. The support for the health maximization principle was weak, and a trade-off between efficiency and equity was preferred. About 70% of the respondents were prepared to sacrifice health gains to achieve increased equity. / digitalisering@umu
15

Patients’ and Spouses’ Perspectives on Coronary Heart Disease and its Treatment

Kärner, Anita January 2005 (has links)
Background: Lifestyle changes and drug treatment can improve the prognosis and quality of life for patients with coronary heart disease (CHD), but their co-operation with suggested treatment is often limited. The aim of this thesis was to study how patients and their spouses conceive CHD and its treatment. Material and Methods: The research design used was inductive and descriptive. The studies were based on three complementary sets of data. Patients with CHD (n=23) and spouses (n=25) were interviewed one year after an episode of the disease. Consecutive patients with CHD derived from another investigation were interviewed within six weeks or one year after the coronary event (n=113). All semi-structured interviews, tape-recorded or from notes taken by hand, were subjected to analysis within the phenomenographic framework. Findings: The patients’ conceptions of CHD varied and were vague, even as judged on a lay level. They were associated with symptoms rather than with the disease. Co-operation with drug treatment was rarely linked to improved prognosis. The patients’ descriptions of benefits from lifestyle changes and treatment did not give the impression of being based on a solid understanding of the importance of such changes. Incentives for lifestyle changes were classified into four categories, all of which contained both facilitating and constraining incentives. Somatic incentives featured direct and indirect physical signals. Social/practical incentives involved shared concerns, changed conditions, and factors connected with external environment. Cognitive incentives were characterised by active decisions and appropriated knowledge, but also by passive compliance with limited insights, and by the creating of routines. Affective incentives comprised fear and reluctance related to lifestyle changes and disease and also lessened self-esteem. All incentives mostly functioned facilitatively. The cognitive and the social/practical incentives were the most prevalent. Spouses’ understanding about the causes of CHD involved both appropriate conceptions and misconceptions. Drug treatment was considered necessary for the heart, but harmful to other organs. Spouses’ support to partners was categorised, and found to be contextually bound. The participative role was co-operative and empathetic. The regulative role controlled and demanded certain behaviours. The observational role was passive, compliant, and empathetic. The incapacitated role was empathetic, unable to support, and positive to changes. The dissociative role was negative to changes and reluctant to be involved in lifestyle changes. Conclusions: These results could be useful in the planning of care and education for CHD patients. The findings also emphasise the importance of adopting a family perspective to meet the complex needs of these patients and their spouses in order to facilitate appropriate lifestyle changes. / On the day of the public defence of the doctoral thesis the status of article V was Submitted.
16

Atrial function and loading conditions in athletes

D'Ascenzi, Flavio January 2017 (has links)
Intensive training is associated with hemodynamic changes that typically induce an enlargement of cardiac chamber. Despite LA dilatation in athletes has been interpreted as a benign adaptation, little evidence is available. The aim of this thesis is to demonstrate that LA size changes in response to alterations in loading conditions and to analyse atrial myocardial function in athletes through the application of novel echocardiographic techniques. We found that top-level athletes exhibit a dynamic morphological and functional LA remodelling, induced by training, with an increase in reservoir and conduit volumes, but stable active volume. Training causes an increase in biatrial volumes which is accompanied by normal filling pressures and stiffness. These changes in atrial morphology are not associated with respective electrical changes. Extending the evidence from adult athletes to children, we found that training-induced atrial remodelling can occur in the early phases of the sports career and is associated with a preserved biatrial function. Finally, in a meta-analysis study of the available evidence we demonstrated that atrial function and size are not affected by aging. In conclusions, athlete’s heart is characterized by a physiological biatrial enlargement. This adaptation occurs in close association with LV cavity enlargement, is dynamic and reversible. This increase in biatrial size is not intrinsically an expression of atrial dysfunction. Indeed, in athletes the atria are characterized by a preserved reservoir function, normal myocardial stiffness, and dynamic changes in response to different loading conditions.
17

Neurohormonal activation, Symptoms and health-related quality of life in patients with atrial fibrillation eligible for radiofrequency ablation

Charitakis, Emmanouil January 2016 (has links)
Atrial fibrillation (AF) is the most common cardiac arrhythmia. In order to improve the management of patients with AF, a better understanding of patients’ arrhythmia-related symptoms and health-related quality of life (HRQoL), as well as a finer grasp of the effect of AF initiation and the revolutionary treatment of radiofrequency ablation (RFA) on neurohormonal balance are of great importance. The aim of this dissertation was to study the effects of RFA and AF initiation on four different neurohormonal systems represented by two cardiac biomarkers: the N-terminal fragment of the proB-type natriuretic peptide (NT-proBNP), the mid-regional fragment of the N-terminal of pro-atrial natriuretic peptide (MR-proANP); and two extra-cardiac biomarkers: the C-terminal fragment of the prodromal molecule of arginine vasopressin (copeptin) and the mid-regional portion of pro-adrenomedullin (MR-proADM). Furthermore, we aimed to correlate objective indicators with the variety of arrhythmiarelated symptoms and HRQoL in patients with AF. We studied 192 consecutive AF patients, eligible for RFA, referred to the University Hospital, Linköping, Sweden between January 2012 and April 2014. Forty-five patients, out of the initially selected sample, were included in the interventional part of the study. Biomarkers were collected from the femoral vein (fv), the coronary sinus (CS) and the left atrium (LA), and from fv immediately and the day after RFA. With regard to the interventional part of the study, 36 patients were randomized to AF initiation and 19 to control group. Biomarkers were retrieved from fv, CS and LA prior to AF initiation (baseline) and 30 minutes later. The Arrhythmia-Specific questionnaire in Tachycardia and Arrhythmia (ASTA) symptom scale was used in order to assess patients’ arrhythmiarelated symptoms. The ASTA HRQoL scale and the generic short-form 36 (SF-36) physical and mental component summaries were used in order to express patients’ disease-specific and overall HRQoL respectively. While analysing the effect of RFA on biomarkers, it was noticed that the level of NTproBNP decreased the day after RFA in participants in AF, compared with the participants in sinus rhythm who showed a slight increase. Regardless of the actual rhythm, the level of MR-proANP showed an increase immediately after RFA was carried out, followed by a decrease the day after. The copeptin level showed a six-fold increase, compared with baseline, immediately after the RFA procedure, while the MR-proADM level increased the day after. The levels of copeptin and MR-proADM were similar in the CS compared to peripheral blood. When it came to the effects of AF initiation on biomarkers, compared with the control group, MR-proANP and NT-proBNP concentrations were increased. Copeptin levels in patients without ischemic heart disease were decreased after the initiation of AF. We also found that signs of anxiety, low-grade inflammation (defined by high-sensitive C-reactive protein levels>3mg/l) and LA dilatation significantly predicted arrhythmiarelated symptoms. Probable depression was the most important predictor of arrhythmiaspecific HRQoL, and obesity and signs of anxiety were the most important predictors of the physical and mental component summaries respectively. AF is a complex arrhythmia that affects the cardiac and extra-cardiac neurohormonal balance directly after its initiation. RFA causes a neurohormonal imbalance not only due to secondary myocardial injury, but also due to other factors such as patient’s actual rhythm, volume overload and procedural stress. Treatable factors such as anxiety, depression and obesity, which can affect HRQoL and symptoms in patients with AF, should be addressed, and possibly a more intensive life style factor modification can be of value.
18

Computer Assisted Coronary CT Angiography Analysis : Disease-centered Software Development

Wang, Chunliang January 2009 (has links)
<p>The substantial advances of coronary CTA have resulted in a boost of use of this new technique in the last several years, which brings a big challenge to radiologists by the increasing number of exams and the large amount of data for each patient. The main goal of this study was to develop a computer tool to facilitate coronary CTA analysis by combining knowledge of medicine and image processing.Firstly, a competing fuzzy connectedness tree algorithm was developed to segment the coronary arteries and extract centerlines for each branch. The new algorithm, which is an extension of the “virtual contrast injection” method, preserves the low density soft tissue around the coronary, which reduces the possibility of introducing false positive stenoses during segmentation.Secondly, this algorithm was implemented in open source software in which multiple visualization techniques were integrated into an intuitive user interface to facilitate user interaction and provide good over¬views of the processing results. Considerable efforts were put on optimizing the computa¬tional speed of the algorithm to meet the clinical requirements.Thirdly, an automatic seeding method, that can automatically remove rib cage and recognize the aortic root, was introduced into the interactive segmentation workflow to further minimize the requirement of user interactivity during post-processing. The automatic procedure is carried out right after the images are received, which saves users time after they open the data. Vessel enhance¬ment and quantitative 2D vessel contour analysis are also included in this new version of the software. In our preliminary experience, visually accurate segmentation results of major branches have been achieved in 74 cases (42 cases reported in paper II and 32 cases in paper III) using our software with limited user interaction. On 128 branches of 32 patients, the average overlap between the centerline created in our software and the manually created reference standard was 96.0%. The average distance between them was 0.38 mm, lower than the mean voxel size. The automatic procedure ran for 3-5 min as a single-thread application in the background. Interactive processing took 3 min in average with the latest version of software. In conclusion, the presented software provides fast and automatic coron¬ary artery segmentation and visualization. The accuracy of the centerline tracking was found to be acceptable when compared to manually created centerlines.</p>
19

Quantification of regional myocardial function by strain rate and strain for evaluation of coronary artery disease : Automated versus manual analysis during acute myocardial infarction and dobutamine stress echocardiography

Ingul, Charlotte Björk January 2006 (has links)
<p>Kvantifisering av hjertets muskelfunksjon med tøyning og tøyningshastighet målt med ultralyd for vurdering av koronar sykdom.</p><p>Automatisert metode versus manuell ved akutt hjerteinfarkt og ultralyd stress test.</p><p>Vanligvis måles hjertets muskelfunksjon med ultralyd, en mye brukt metode for å diagnostisere hjertesykdommer. Vurderingen av muskelfunksjonen baserer seg i dag på en subjektiv visuell gradering av bevegelsen av hjertemuskelen, og dette krever erfaring. En ny automatisert diagnostisk ultralydsmetode basert på måling av hastigheten i hjertemuskelen gir et kvantitativt mål på muskelens tøyning og sammentrekning. Den nye metoden gir ny og mer detaljert informasjon om hjertets funksjon og om pasientens prognose enn vanlig ultralydsvurdering.</p><p>Den nye metoden er mer presis ved oppfølgning etter hjerteinfarkt. Et hjerteinfarkt gir nedsatt bevegelse av muskelen og måles med den nye metoden som nedsatt hastighet som muskelen forkortes med. Små forandringer i den skadde hjertemuskelen, ikke alltid synlige for øyet, kan mer nøyaktig følges over tid med den nye metoden. Utbredelsen av hjerteinfarktet kan også vurderes mer nøyaktig.</p><p>Det samme gjelder når angina vurderes under belastning. Når en pasient ikke kan sykle eller gå på tredemølle brukes en medisinsk belastningstest. Ved å belaste hjertet med et medikament som øker hjertemuskelens arbeid samtidig med en ultralydundersøkelse, kan vi oppdage redusert blodforsyningsreserve i hjertet. Stresstesten hjelper til med å vurdere om en trang blodåre bør åpnes etter et hjerteinfarkt, og til å vurdere pasienters risiko for hjertekomplikasjoner før en større operasjon. Den nye metoden gir i tillegg mer informasjon om den langsiktige prognosen sammenlignet med den gamle metoden. Vi har funnet at den nye ultralydsmetoden er mer presis (gir større diagnostisk treffsikkerhet i diagnostikk av koronarsykdom) sammenlignet med den gamle.</p><p>Måling av sammentrekningshastigheter i hjertemuskelen ble utviklet og testet på Institutt for sirkulasjon og bildediagnostikk ved NTNU av Andreas Heimdal og Asbjørn Støylen i 1998. Metoden trengte teknisk videreutvikling og testing i et større pasientmateriale. Metoden har ikke fått stor utbredelse på sykehusene pga støyfylte kurver og tidskrevende analyser, men med denne automatiserte metoden blir brukervennligheten større som muliggjør klinisk bruk.</p> / Paper I and II preprinted with kind permission of Elsevier, sciencedirect.com
20

Distansuppföljning av ICD-patienter : En hälsoekonomisk utvärdering

Sandås, Therese, Karlström, Micaela January 2009 (has links)
<p>Uppsatsens syfte är att undersöka vilka ekonomiska effekter införandet av distansuppföljning för ICD-patienter har ur ett samhällsperspektiv. Delsyftet är att identifiera ekonomiska argument och kvalitativa aspekter för och emot införandet av tjänsten distansuppföljning.</p><p>Författarna har kommit fram till ett antal slutsatser. Att införa distansuppföljning som uppföljningsmetod för ICD-patienter istället för konventionella återbesök på sjukhus innebär stora kostnadsbesparingar. Nettonuvärdet uppgår till drygt 268 miljoner kronor efter femton år. Vid tidsperiodens slut erhålls en kostnadsbesparing på cirka 35,6 procent. De ekonomiska fördelarna överstiger kostnaderna redan efter ett år, och hela investeringskostnaden återfås efter sju år. Kvalitativa argument som talar för distansuppföljning är tidsbesparingar, förenklad uppföljning, bättre övervakning och att patienterna upplever en större trygghet.</p>

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