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Coming theses from other universities

  • Thoracic Endovascular Aortic Repair : Clinical and morphological outcomes Author: Tina Hellgren Link: Publication date: 2021-11-25 12:11

    In the years following its introduction in the late 1980’s, thoracic endovascular aortic repair (TEVAR) rose as a minimally invasive alternative to open surgical repair of thoracic aortic disease. As a result, an expanding group of patients are receiving invasive treatment, even though evidence in the area is still scarce. The overall aim of this thesis was to study the outcomes of modern treatment of thoracic aortic disease – TEVAR and hybrid repair – by analyzing data from local and international cohorts.

    Paper I includes an evaluation of outcomes of TEVAR for intact and ruptured thoracic aortic aneurysm (TAA) at a tertiary referral center (1999 to 2014). Survival was unexpectedly poor after ruptured TAA repair, only one third of the patients were alive at 3-years follow-up. Intact TAA repair was associated with low perioperative mortality and acceptable 5-year survival.

    Paper II analyses aortic remodelling, complications, reinterventions and survival after TEVAR for subacute and chronic type B aortic dissection at a tertiary aortic center (1999-2015). TEVAR induced positive remodelling, characterized by false lumen thrombosis and shrinkage accompanied by true lumen expansion, of the thoracic but not the abdominal aorta. Reintervention due to aortic dilatation distal to the stent graft was common.

    Paper III, an international registry-based multicenter study of 9518 TEVAR cases from 2012 to 2016, demonstrated substantial international differences in practice patterns. The large dataset provides a point of reference for short-term outcome after TEVAR in current practice.   

    Paper IV, a single-center study of 50 consecutive patients who underwent frozen elephant trunk repair of the aortic arch (2006 to 2020), confirmed that whilst this procedure is associated with morbidity and mortality, the technique provides an adequate bridge to endovascular repair of the downstream aortic segments, which was common during follow-up. The repair was shown to induce positive aortic remodeling in the thoracic but not abdominal aorta, in patients with chronic aortic dissection.

    In conclusion, this thesis provides insights into the rapidly evolving field of TEVAR, including an overview of current practice as well as clinical and morphological outcomes.

  • Clinical Impact of Bloodstream Infections – Characterization, Risk factors and Outcome Author: Martin Holmbom Link: Publication date: 2021-11-25 09:00

    Bloodstream infection (blood poisoning) and antibiotic resistance are increasing worldwide, and already cause the loss of millions of human lives each year. According to the World Health Organisation (WHO), bloodstream infections (BSIs) represent 20% of global mortality on a par with cardiac infarct, stroke, and major trauma. BSI may occur when bacteria from a focus of infection gain access to the circulation (bacteraemia). BSIs are usually divided into two subclasses: community- and hospital-onset infections, since disease this involves different patient groups, types of bacteria, and reasons for infection. Compared to other countries, Sweden has been fortunate in having a relatively low death rate from BSI and low antibiotic resistance. However, as our lifestyle changes, the age of the population increases with more disease as a result, and as the healthcare system responds, death from infection and antibiotic resistance are on the increase. It is important that we recognise ”warning symptoms” if we are to manage BSIs correctly and initiate effective treatment. It is difficult to design individualised empirical treatment, so it is very important to be aware of risk factors for BSI and local resistance patterns, and to have an effective management programme. 

    Bacterial resistance to antibiotics is an increasing problem, especially in bowel organisms that can cause infections that are very difficult to treat. In short, antibiotic resistance arises as a result of evolutionary processes where bacteria protect themselves by developing resistance genes. These genes can be exchanged between similar organisms or transmitted to others that in turn cause resistant infection. The use of antibiotics leads to an evolutionary/selection process leading to resistance in bacteria, both normal and pathogenic, enabling resistant organisms to survive, thrive, and go on to cause infection. Antibiotic resistance is a threat to global health.  

    This thesis aims to increase our awareness of a large group of patients who suffer bloodstream infection. BSIs are increasing globally, and the death toll is high. Antibiotic resistance is an increasing threat to the health of the population, and we are inundated by alarming reports of resistance getting out of control. What is the situation in Sweden, and can we identify risk factors for BSI and mortality? 

    In Study I, our aim was to study the incidence and mortality of BSI in Östergötland. To be able to do this, a large patient population stretching over several years was required. The study design was thus population-based in the form of an observational cohort study where all blood culture results from 2000 to 2013 were analysed, and evaluated from clinical data. A total of 109,938 results were analysed resulting in 11,480 BSIs. 

    We saw that the incidence of BSI increased by 64% (mostly community-onset BSIs). We also saw that mortality increased by 45%. These results illustrate the importance of nationwide cooperation to combat the increasing problem of BSI and its mortality, and the establishment of a nationwide BSI register. 

    The aim of Study II was to assess resistance development in Östergötland and its relationship to mortality. A total of 9,587 microorganisms were analysed between 2008 and 2016. We observed an increase in quinolone resistance (3.7-7.7%) and cephalosporin resistance (2.5-5.2%) amongst Enterobacteriaceae. We then looked at BSIs caused by multiresistant bacteria showing a total of 245 cases (2.6%); an increase of 300%. Despite this, we did not see an increased mortality in this group. 

    There are several possible explanations for the increase in BSI mortality of which antibiotic resistance is a predominant factor globally. We were unable to show this in our study, even so mortality is increasing and is currently at a high level. In Study III we therefore analysed risk factors associated with death during a community-acquired BSI, focusing on preliminary prehospital and hospital management. In a retrospective case-control study on 195 deaths matched 1:1 regarding age, gender, and microorganism, with 195 survivors (controls). Results showed that many patients had contacted the primary healthcare system because of infection before they became severely ill, and that the strongest affectable risk factor for death was delay (>24h) between primary healthcare visit and admission to hospital. This shows the need for increased awareness in society and amongst the medical profession of those patients at risk and symptoms that should raise the alarm, leading to more rapid treatment. 

    In Studies I and II we found an increase in both BSIs and mortality, we also saw an increase in antibiotic resistance and multiresistant bacteria, mainly ESBL-producing E. coli. On the other hand, we did not see any coupling between multiresistance and mortality in this Swedish population. E. coli is a gram-negative bacteria that causes most BSIs. Since E. coli is predominantly a urine tract pathogen, Study IV aimed to study BSIs caused by ESBL-producing E. coli originating from the urinary tract. We studied the prevalence of E. coli clones, resistance genes and risk factors, as well as any signs of increased mortality from ESBL-producing E. coli compared to sensitive E. coli. Our main finding was a surprisingly low mortality from ESBL-producing E. coli (3%). Most patients in the ESBL-producing E. coli group received inadequate antibiotic treatment for at least 48h, but we did not see any sign of increased mortality or risk for serious sepsis with circulatory failure in this group. This finding is interesting and opens up for new studies on virulence factors and immunological factors that govern the immune response to BSI. 

    The implementation of cost-effective monitoring systems including clinical microbiological epidemiology and early identification of BSI, together with information campaigns aimed at the public as well as healthcare personnel regarding patients at risk and symptoms giving cause for alarm, should lead to a radical reduction in morbidity and mortality from BSI. This requires new diagnostic tools to individualise both antibiotic treatment and targeted management based on microorganism virulence factors. Modernisation of the medical journal system with algorithms aimed at early identification of risk patients and automated suggestions for empirical antibiotic treatment based on antibiotic resistance seen in previous cultures and local resistance patterns, would certainly improve management. Furthermore, new immunological tests showing the type of immunological reaction to a serious BSI will lead to individualised immunotherapy that, together with antibiotic treatment, will further improve patient care in this important group.  

  • Cultural activities and health : Singer, patient, and healthcare staff perspectives. From feelings to biology Author: Christina Grape Viding Link: Publication date: 2021-11-23 13:39

    Objectives. The aim of this thesis was to explore and illuminate possible associations between various cultural activities and assessments of well-being, health, stress and emotions in a didactic setting and healthcare settings for singers, patients, and healthcare staff. 

    Material and methods. Paper I describes an empirical intervention study with repeated measures from a small cohort of singers, before, during and after a singing lesson. Physiological and endocrinological measures, as well as self-ratings were used. A two-way analysis of variance (ANOVA), as well as non-parametric tests were used. Paper II describes a randomised controlled trail for women with exhaustion symptoms participating in an intervention called the “culture palette”, consisting of six different cultural activities. Exhaustion, alexithymia, sense of coherence and self-rated health with standardised scales were assessed. A Linear Mixed Models were used. Paper III describes a study using a phenomenological hermeneutical method in analysing focus group interviews with women with burnout symptoms and cultural producers and separate interviews with health care managers to elucidate the experiences of participating in the culture palette. Paper IV describes a study with a phenomenological hermeneutical method analysing focus group interviews with healthcare staff members about their experiences of participating in self-chosen cultural activities.

    Results. The analysis of paper I showed increased wellbeing and joy in amateur singers. The professional singers showed better cardio-physiological fitness during singing. Both groups experienced more energy and relaxation after the singing lesson. The analysis of paper II showed decreased symptoms of exhaustion, alexithymia and increased self-rated health in the women after participation in the cultural activities. However, there was no significant differences between intervention and control groups regarding sense of coherence (SOC). Paper III describes the analysis of the interviews and shows three themes, where the culture palette impacted on the level of the body, group and indirectly on the managers and healthcare organisation. Paper IV describes the analysis of the interviews and shows three themes where cultural activities had a positive impact on the physical/psychological level, and enhanced work relations. Challenges in implementing cultural activities in the healthcare organisation were illuminated. 

    Conclusion. The cultural activities included in these studies show beneficial effects on health for individuals and groups, as well as for healthcare organisations. The multimodal components integrated in cultural activities exhibit possibilities of enhancing health, wellbeing and preventing and managing stress reactions. Cultural activities can enable the development of a more sustainable healthcare and eventually a more sustainable society.