Background: The 30-day readmission rate is considered a quality of care measure for providers and has become important because providers might face reduced reimbursement from any increase in unplanned readmissions Objective: The aim of the first chapter is to investigate the waiting-length of stay (WLOS) and post-length of stay (PLOS) on the 30-day readmission. In the second chapter, we examined the hospital procedural volume and hospital quality on the 30-day readmission. Our objective in the third chapter is to examine the zip code-level SES factors on the 30-day readmission rates. Participants: patients undergoing isolated coronary artery bypass grafting (CABG) in Virginia Methods: A retrospective study design has been conducted using a multi-level logistic model of increasing complexity for all three chapters. The sample used was from the Virginia Cardiac Surgery Quality Initiative (VCSQI) of the periods 2008-2014, the dataset included patient characteristics. Afterward, we merged the sample with both the Virginia Health Information (VHI) to obtain hospital characteristics (ownership, teaching status, and location), and Agency for Healthcare Research and Quality (AHRF) to obtain county-socio-economic status (SES) characteristics (education, employment, and median household income), the previous SES was used for chapter’s one and two. In chapter three, instead of AHRF, we merged the sample with the American Community Survey (ACS) to obtain zip code-SES characteristics (employment, median household income, education, median house price). The main outcome was the 30-day readmission rate. The analytical sample of chapter one n = 22,097, in chapter two the sample n = 25,531, while in chapter three the sample n= 25,829. We conducted a sensitivity analysis in all three chapters. In chapter one we analyzed the data at the patient level, in chapter two we analyzed the data at the hospital level, while in chapter three we conducted the analysis at the area zip code level. Results: In chapter one, we found that readmitted patients after a prolonged PLOS had increased odds of readmission, by 68.7%, compared to readmitted patients with a shorter PLOS in the fully adjusted model; while, WLOS was not significant at the P < 0.05. In chapter two, the fully adjusted model displayed significant results with a reduced odds in readmissions by 22.8% in the middle-volume hospitals compared to the low-volume hospitals, while the middle-quality hospitals had increased odds of readmission by 23.5% compared to the low-quality hospitals. In chapter three, statistically, we did not find that area zip code-SES had an effect on the 30-day readmission rate. While, geographically, we found that addresses of individuals were clustered in certain areas of Virginia. Conclusion: In chapter one, patients undergoing CABG and experience a prolonged PLOS of > 6 days are at risk to be readmitted within 30-days of the procedure. In chapter two, the higher volume hospitals (middle-volume) compared to low-volume hospitals showed a significant reduction in odds in the 30-day readmissions, especially after adjusting the model with hospital quality. In chapter three, even though, there was no association of area-SES with 30-day readmission, in the maps, we found a cluster of patient addresses in the southern parts of Virginia with an increased readmission, which is considered underprivileged area; and the fact might be due to the proximity of these areas to cardiovascular hospitals. Policy Implication: In chapter one, the study provided a model for clinicians to stratify patients at risk of readmission, especially patients with risks of staying longer in the hospital after CABG. In chapter two, policymakers and the CMS should find new ways to help hospitals with low-volumes to reduce their isolated-CABG readmission rates and be able to compete with high-volume hospitals. In chapter three, no significant correlation between area-SES and readmission for patients who underwent CABG was found; these backs prior notion that SES should not be adjusted for the reimbursement penalties of the Hospital Readmission Reductions Program (HRRP) on hospitals

Aims: Coronary Revascularization (CR) has increased patients' survival rate globally. However, the lack of a consensus definition of Health Related Quality of Life (HRQoL) and the different methodological and conceptual approaches adopted by researchers in the cardio-revascularization field create an incomplete picture of the influence of CR on individuals' HRQoL. By using mixed methodology, the current research aimed to explore Greek CHD patients' perspectives of their HRQoL after CR (Coronary Artery Bypass Grafting (CABG) or Percutaneous Coronary Interventions (PCI)), as well as detect and explain individual disparities. Method: Two studies were conducted with a total sample of 487 individuals: (1) The translation and validation of the Coronary Revascularization Outcome Questionnaire (CROQ) into Greek and (2) The longitudinal mixed methods study, the main study of the thesis, following a sequential explanatory design with two research components: a) the longitudinal quantitative component aimed to detect changes in patients' HRQoL (both overall and its subdomains) following CR over a 12-month period based on individuals' subjective evaluation as captured by the CROQ, detect the influence of CR type on the outcome and to explore potential predictors (individuals' demographic, clinical and behavioural features). Data were analysed using multilevel modelling; b) the qualitative component aimed to capture individuals' lived experience, their view and understanding of themselves and their life approximately 12 months after treatment using Interpretive Phenomenological Analysis (IPA). Results/findings: Based on participants' subjective evaluations as captured by the validated Greek version of the CROQ, one year after CR Greek Coronary Heart Disease (CHD) patients experience an increase in their HRQoL level compared to prior to CR. The pattern of change though is not constant; initially HRQoL increases with time, and then decreases again, however, remaining much greater compared to prior to CR one year after CR. Regarding the influence of the CR type of treatment on patients' HRQoL level, a year after CR mixed findings are revealed. In the symptoms and physical functioning subdomain, patients treated with CABG demonstrate a greater increase compared to patients treated with PCI. In the psychosocial functioning subdomain no difference is found. In the cognitive functioning subdomain, patients treated with CABG demonstrate a decline compared to their cognitive functioning prior to the CR. Various demographic, clinical and behavioural features are demonstrated to be predictors of the outcome though not consistent for all subdomains. The main predictors associated with larger positive changes following CR seem to be sex, BMI and smoking; females with low BMI that do not smoke tend to demonstrate a greater increase in HRQoL after CR. According to individuals' lived experience, participants, reflecting on their experience one year after treatment, perceive CR as a simple process and their negative experience is mostly related to medical care. Many participants with no symptoms or adverse effects tend to misperceive CHD, viewing their health condition as an acute disease treated with CR. Trying to understand disease causality they tend to adopt medical discourse especially in relation to stress as a factor that can be controlled by themselves and reflect on their own responsibility as a causal factor. Feeling grateful for being alive, sensing a different body, a 'revitalized body' as many participants suggest, as well as a fear of re-occurrence or disease progression motivate individuals to work on aspects of the self related to the CHD development in an effort to regain control over their life which has been reduced after the CHD diagnosis. In effect a dramatic change in how the self and life are viewed is reported, highlighting a positive growth; a greater appreciation of life, a personal growth and effort to build more meaningful relationships. Challenges that participants face in modification of their lifestyle are attributed to both external and internal factors. Concerning smoking participants' accounts point to a lack of knowledge regarding the relationship between smoking and CHD, a lack of support (by experts or family members) and conscious denial as a way to cope with every day anxiety and stress, but also a pleasure in everyday life. The findings provide a complementary insight into perceptions of individuals with CHD about their quality of life one year after CR, suggesting that other factors beyond CR may influence their perspectives. Conclusions/implications: This study highlights the benefits of using a mixed methods longitudinal design in exploring HRQoL. Both the quantitative and qualitative findings support the notion that HRQoL is a multidimensional, continuously changing concept, providing support for the Wold Health Organization's definition. Also, the findings suggest that CR has a positive influence on individuals' HRQoL. The effect of the CR type needs further investigation as mixed findings are observed in the present thesis. Moreover, it seems difficult to investigate the pure effect of CR on individuals' HRQoL without taking into consideration individuals' adjustment processes and positive growth triggered by the CR. The self regulation model (SRM) might be considered a useful theoretical framework for developing theory-based interventions aiming to alter patients' false beliefs since individuals' making-meaning process seems to be aligned with it. Finally, the complementary insights concerning smoking may help health care providers to develop smoking cessation interventions tailored to cardiac patients.

Ziel: Die Ergebnisse nach aortokoronarer Bypassoperation (CABG) unterscheiden sich bei Patienten mit schlechter linksventrikulärer Pumpfunktion deutlich von denen bei Patienten ohne Einschränkungen derselben. Das Ziel dieser Studie war die Untersuchung des Einflusses einer reduzierten linksventrikulären Ejektionsfraktion (LVEF), eines vergrößerten linksventrikulären enddiastolischen Volumenindexes (LVEDVI) und eines erhöhten linksventrikulären enddiastolischen Druckes (LVEDP) auf das postoperative "outcome". Material und Methodik: Im Rahmen dieser retrospektiven Studie wurden 148 Patienten mit einer koronaren Herzkrankheit (KHK) und eingeschränkter Ejektionsfraktion (EF / Aim: Results of coronary artery bypass grafting (CABG) in patients with poor left ventricular ejection fraction (LVEF) differ from those in patients with normal LVEF. The aim of the study was a investigation into the influence of reduced LVEF, augmented left ventricular enddiastolic volume index (LVEDVI) and elevated left ventricular enddiastolic pressure (LVEDP) on the outcome of CABG. Methods: 148 Patients with LVEF < 50% underwent CABG. Exercise tolerance and LVEF were determined pre- and postoperatively. Three subgroups were built to distinguish the influence of reduced LVEF on postoperative outcome. Group I: LVEF < 30%, group II: 30% < LVEF < 40%, group III: 40% < LVEF < 50%. Results: Exercise tolerance rised from a preoperatively mean of 70 Watt to 97 Watt postoperatively. Mean NYHA class was 2,7 pre- and 1,7 postoperatively. There were no significant differences in the results of the three subgroups. Perioperative mortality in group I was 6,3%. Actuarial 1 and 2 years survival in this group is at 81 and 70% respectively. These results differ clearly from those of group II and III. Perioperativ mortality was 2,2% in group II and 1,4% in group III. Actuarial 1 and 2 years survival is at 93 and 84% in group II and at 95 and 83% in group III. There was no difference in postoperative outcome of patients with LVEDP > 12mmHg in comparison to patients with LVEDP < 12mmHg. Patients with LVEDVI > 100 ml/m2 had a sifnificant higher peri- and postoperative mortality than patients with LVEDVI < 100 ml/m2. Mean LVEDVI of those patients, whose LVEF increased postoperatively, was 84 ml/m2. Patients with no change in LVEF had a mean LVEDVI of 122 ml/m2. Conclusion: CABG in patients with reduced LVEF improves exercise tolerance and quality of life. Poor LVEF (< 30%) and augmented LVEDVI are predicting higher peri- and postopertive mortality. Postoperative increase of LVEF is unlikely in patients with enlarged left ventricels.