Quantitative Cardiac Magnetic Resonance Imaging Biomarkers for the Characterisation of Ischaemic Cardiomyopathy

Our understanding of the processes that determine outcomes in patients with ischaemic cardiomyopathy is based on conventional physiological concepts such as ischaemia and viability. Qualitative methods for characterising these processes tend to be binary and often fail to capture the complexity of the underlying biology. Importantly, these are perhaps inadequate to evaluate treatment effects, including the impact of coronary revascularisation. The aim of this thesis was to deploy novel quantitative cardiac magnetic resonance (CMR) techniques to evaluate and distinguish between the pathophysiological processes that determine outcomes in patients with ischaemic cardiomyopathy, through integration of anatomical, functional, perfusion and tissue characterisation information. The work is centred around the use of coronary artery bypass graft (CABG) surgery as the method for revascularisation, and focuses on the impact of myocardial blood flow alterations on cardiac physiology and clinical outcomes. In this work, I first evaluate the impact of surgical revascularisation on myocardial structure and function in patients with impaired left ventricular (LV) systolic function, using paired assessments before and after CABG. I found that at 6 months following revascularisation, despite improvement in functional capacity, more than a third of total myocardial segments examined are no longer considered revascularised. As a result, the overall augmentation in global myocardial blood flow (MBF) following CABG surgery is significantly blunted. There are however technical concerns regarding the quantitative estimation of myocardial blood flow in patients with coronary artery grafts, particularly in relation to the impact of long coronary grafts on contrast kinetics. I therefore evaluated the impact of arterial contrast delay on myocardial blood flow estimation in patients with left internal mammary artery (LIMA) grafts. I showed that absolute MBF estimation is minimally affected by delayed contrast arrival in patients with LIMA grafts, and that irrespective of graft patency, residual native disease severity is a key determinant of myocardial blood flow. Following these findings, I then assessed the prognostic impact of myocardial blood flow in a large cohort of patients with prior CABG. The only imaging study to date examining the prognostic role of quantitative perfusion indices in this population, it demonstrated that both stress MBF and myocardial perfusion reserve (MPR) independently predict adverse cardiovascular outcomes and all cause-mortality. Finally, using the existing quantitative perfusion technique and its associated framework, I co-developed and implemented a non-invasive, in-line method of measuring pulmonary transit time (PTT) and pulmonary blood volume (PBV) during routine CMR scanning. I then found that both imaging parameters can be used as independent quantitative prognostic biomarkers in patients with known or suspected coronary artery disease

Bridging Knowledge Gaps in the Management of Acute Coronary Syndromes

Contexte L’occlusion d’une artère du cœur cause un syndrome coronarien aigu (SCA) soit avec une élévation du segment ST (IAMEST) ou sans élévation du segment ST (1). Le traitement des patients avec un IAMEST requiert soit une intervention coronarienne d’urgence (ICP primaire) ou une thérapie fibrinolytique (FL). La thérapie FL peut être administrée soit dans un contexte pré-hospitalier (PHL) ou à l’hôpital. Une prise en charge précoce des patients avec SCA peut être améliorée par un simple indice de risque. Objectifs Les objectifs de cette thèse étaient de : 1) comparer l’ICP primaire et la thérapie FL (2); décrire plusieurs systèmes internationaux de PHL; (3) développer et valider un indice de risque simplifié pour une stratification précoce des patients avec SCA. Méthodes Nous complétons des méta-analyses, de type hiérarchique Bayésiennes portant sur l’effet de la randomisation, d’études randomisées et observationnelles; complétons également un sondage sur des systèmes internationaux de PHL; développons et validons un nouvel indice de risque pour ACS (le C-ACS). Résultats Dans les études observationnelles, l’ICP primaire, comparée à la thérapie FL, est associée à une plus grande réduction de la mortalité à court-terme; mais ce sans bénéfices concluants à long terme. La FL pré-hospitalière peut être administrée par des professionnels de la santé possédant diverses expertises. Le C-ACS a des bonnes propriétés discriminatoires et pourrait être utilisé dans la stratification des patients avec SCA. Conclusion Nous avons comblé plusieurs lacunes importantes au niveau de la connaissance actuelle. Cette thèse de doctorat contribuera à améliorer l’accès à des soins de qualité élevée pour les patients ayant un SCA.Background Acute occlusion of an artery of the heart results in acute coronary syndromes (ACS), either with ST-segment elevation (STEMI) or without ST-segment elevation (1). STEMI requires urgent treatment to restore coronary artery flow either by primary percutaneous coronary intervention (PCI) or fibrinolytic therapy (FL) (2). Although several randomized controlled trials (RCTs) demonstrate the superiority of primary PCI in reducing mortality compared to FL (2), the benefit of primary PCI over FL remains uncertain in unselected “real-life” patients (3,4). FL can be administered either in the pre-hospital setting (i.e., pre-hospital FL (PHL)) or at the hospital. PHL is rarely available outside Europe (5,6). Insights into the organization of PHL systems of care may promote more widespread use of PHL. Risk stratification of ACS patients should be prompt to ensure timely PCI for high-risk patients and to avoid unnecessary intervention in low-risk patients (7). Despite the availability of numerous ACS risk scores, there is still no simple risk score that can be easily applied in the initial management of ACS patients (8). Objectives The objectives of this doctoral dissertation were to address these current knowledge gaps in the optimal management of ACS. The objectives were to: 1) evaluate the efficacy, effectiveness, and safety of primary PCI and FL, (2) describe the infrastructure, processes and outcomes of several international PHL systems; and (3) develop and validate a novel clinical risk score for early risk stratification of ACS patients. Methods To address these objectives, I completed Bayesian hierarchical random-effects meta-analyses of published RCTs and observational studies which compare primary PCI and FL in patients with STEMI. I undertook a survey of the infrastructure, processes and outcomes of PHL in several European and North American pre-hospital emergency systems. Finally, I developed and validated an ACS risk score called the Canadian ACS (C-ACS). Results Primary PCI was superior to FL in reducing short-term mortality in RCTs and observational studies. However, the long-term survival benefit of primary PCI was noted only in RCTs, and not in the observational studies. PHL can be effectively delivered by health care professionals with variable levels of expertise. The new risk score, C-ACS, has good discriminant properties for short- and long-term mortality in patients with ACS. Conclusions The first manuscript of this dissertation has been recognized as one of the most valuable recent publications in STEMI management and has contributed to reorganization of STEMI care in Ontario. The other two manuscripts in this dissertation provide practical information and tools for health professionals caring for patients with ACS. In summary, this doctoral dissertation has and will continue to contribute to improve access to high quality care for patients with ACS

Implementation of Same Day Discharge Following Elective Percutaneous Coronary Intervention

High rates of Cardiovascular disease (CVD) and ischemic heart disease (IHD) have led to ever-increasing numbers of percutaneous coronary interventions (PCI) performed. The prevalence of IHD and subsequent PCI has been found to limit bed availability and access to cardiovascular care. Historically, the standard of care following elective PCI has included overnight observation (OO) though clinical advances to PCI procedures have made it possible for same day discharge (SDD) following elective PCI. There are many benefits of SDD following elective PCI that include increased access to cardiovascular care, hospital cost savings, and patient satisfaction without compromising patient safety. The DNP project took place at an inpatient facility in Pulaski County, Arkansas where practice most often included OO following elective PCI. The purpose of the project was to increase access to cardiovascular care through the creation and implementation of a SDD protocol following elective PCI. The overall project aim was to increase the percentage of SDD to 50% by March 31, 2021. The project did not meet this goal as implementation failed during the planned implementation period at the clinical site due to the lack of physician engagement. Despite the lack of SDD protocol implementation, data from the 10-week collection period was analyzed to describe baseline data and current practices at the clinical site. During the 10-week collection period, 20 of 55 patients, or 36.36%, were discharged via other non-established SDD methods. The SDD protocol is still projected to become the standard of practice at the clinical site after future implementation

Ischemic Heart Disease

Cardiovascular disease (CVD) is ranked as the leading cause of death world wide, responsible for 17.1 million deaths globally each year. Such numbers are often difficult to comprehend. A coronary even occurs every 25 seconds and CVD kills one person every 34 seconds. 35 people under 65 years of age die prematurely every day due to CVD. The incidence of CVD has declined in recent years due to a better understanding of the pathology, implementation of lipid lowering therapy, new drug regimens and advances in acute surgical intervention. The disease burden has a great financial impact on global healthcare systems and major economic consequences for world economies. This text reviews the epidemiology, development, risk factors, diagnosis and treatment of ischemic heart disease

New Technologies for the Treatment of Coronary and Structural Heart Diseases

There has been significant progress in the field of interventional cardiology, from the development of newer devices to newer applications of technology, resulting in improved cardiovascular outcomes. The goal of this Special Issue is to update practicing clinicians and provide a comprehensive collection of original articles, reviews, and editorials. To this end, we invited state-of-the-art reviews, including reviews of new technology and therapeutics, as well as original research in this area to be considered for inclusion in this issue. Examples include the history and evolution of interventional techniques, reviews of specific devices and technologies for coronary artery disease (i.e., stent technology, atherectomy devices, coronary physiology, intracoronary imaging, and robotics), structural heart diseases (i.e., ASD: atrial septal defect; LAAC: left atrial appendage closure; MC: MitraClip; PFO: patent foramen ovale; TAVI: transcatheter aortic valve implantation), advances in the management of challenging coronary anatomy, new biomarkers of cardiovascular disease (noncoding RNAs, etc.), and interventional techniques in the management of heart failure, peripheral arterial diseases, and pulmonary embolism. This Special Issue presents the most recent advances in the field of coronary and structural heart diseases as well as their implications for future patient care

Improving care for people undergoing percutaneous coronary interventions: elements of effective interventions

Percutaneous coronary interventions (PCIs) are a frequent strategy for myocardial revascularisation in both the elective and emergency setting. In contrast to surgical techniques such as coronary artery bypass grafting (CABG), there is less procedural burden and a reduction in hospitalisation times. This rapid treatment means a reduced exposure of the individual to healthcare providers in the acute care setting limiting the time to prepare individuals and their families to cope and adjust to living with a chronic condition.In spite of the expansive research in respect of acute coronary syndromes (ACS), PCI and CABG, there is substantially less person centred research focussing on the needs of the individual undergoing PCI. Similarly, in spite of the number of evidence based practice guidelines for ACS and PCI, evidence supporting specific PCI nursing practice remains of a low level and minimally mentioned in practice guidelines. This thesis was undertaken to address these gaps in knowledge.The Chronic Care Model (CCM), promoting evidence based practice, communication and coordination of care for people with chronic conditions has informed the study design, implementation and interpretation of findings.Using the approach of the patient journey and the CCM, a sequential mixed method study was undertaken to describe the barriers and facilitators to improving the care outcomes of people undergoing PCI. Firstly, a study describing the clinical and demographic characteristics of individuals undergoing PCI and their perception of cardiovascular risk was completed. Secondly, a qualitative multi method study investigating patients’, carers’ and healthcare providers’ perceptions of the barriers, facilitators and opportunities for improving PCI care was conducted. Thirdly, an online survey of cardiovascular nurses’ beliefs, values, and practices. This survey was informed by a comprehensive literature review and issues identified through a consensus conference.Fourthly, clinical practice guidelines for PCI nursing care were developed to address limitations in providing coordinated and evidence based nursing care. A systematic method was adopted from the National Health and Medical Research Council’s recommended approach for developing guidelines. This project was conducted under the auspices of the Australasian Cardiovascular Nursing College and the Cardiovascular Nursing Council of the Cardiac Society of Australia and New Zealand; both peak cardiovascular nursing bodies in Australia and New Zealand.Finally, based upon study finding identifying challenges in communication and coordination across care settings, elements of effective interventions aimed at improving risk reduction and secondary prevention uptake have been identified.The series of studies presented in this thesis have contributed to ability of nurses to improve the health outcomes of individuals undergoing PCI across the care continuum. Information obtained from the series of studies in this thesis have provided useful information for further research in developing and implementing effective strategies to improve care for individuals undergoing PCI

A systematic review of patient reported factors associated with uptake and completion of cardiovascular lifestyle behaviour change

Background: Healthy lifestyles are an important facet of cardiovascular risk management. Unfortunately many individuals fail to engage with lifestyle change programmes. There are many factors that patients report as influencing their decisions about initiating lifestyle change. This is challenging for health care professionals who may lack the skills and time to address a broad range of barriers to lifestyle behaviour. Guidance on which factors to focus on during lifestyle consultations may assist healthcare professionals to hone their skills and knowledge leading to more productive patient interactions with ultimately better uptake of lifestyle behaviour change support. The aim of our study was to clarify which influences reported by patients predict uptake and completion of formal lifestyle change programmes. Methods: A systematic narrative review of quantitative observational studies reporting factors (influences) associated with uptake and completion of lifestyle behaviour change programmes. Quantitative observational studies involving patients at high risk of cardiovascular events were identified through electronic searching and screened against pre-defined selection criteria. Factors were extracted and organised into an existing qualitative framework. Results: 374 factors were extracted from 32 studies. Factors most consistently associated with uptake of lifestyle change related to support from family and friends, transport and other costs, and beliefs about the causes of illness and lifestyle change. Depression and anxiety also appear to influence uptake as well as completion. Many factors show inconsistent patterns with respect to uptake and completion of lifestyle change programmes. Conclusion: There are a small number of factors that consistently appear to influence uptake and completion of cardiovascular lifestyle behaviour change. These factors could be considered during patient consultations to promote a tailored approach to decision making about the most suitable type and level lifestyle behaviour change support

ACC/AHA guidelines for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the management of patients with unstable angina)

The ACC/AHA Task Force on Practice Guidelines was formed to make recommendations regarding the diagnosis and treatment of patients with known or suspected cardiovascular disease. Coronary artery disease (CAD) is the leading cause of death in the United States. Unstable angina (UA) and the closely related condition non–ST-segment elevation myocardial infarction (NSTEMI) are very common manifestations of this disease. In recognition of the importance of the management of this common entity and of the rapid advances in the management of this condition, the need to revise guidelines published by the Agency for Health Care Policy and Research (AHCPR) and the National Heart, Lung, and Blood Institute (NHLBI) in 1994 (1) was evident. This Task Force therefore formed the current committee to develop guidelines for the management of UA and NSTEMI, supported by the Agency for Healthcare Research and Quality’s USCF-Stanford Evidence-Based Practice Center. This document should serve as a useful successor to the 1994 AHCPR guideline

Acute Coronary Syndromes

This book has been written with the intention of providing an up-to-the minute review of acute coronary syndromes. Atherosclerotic coronary disease is still a leading cause of death within developed countries and not surprisingly, is significantly rising in others. Over the past decade the treatment of these syndromes has changed dramatically. The introduction of novel therapies has impacted the outcomes and surviving rates in such a way that the medical community need to be up to date almost on a "daily bases". It is hoped that this book will provide a timely update on acute coronary syndromes and prove to be an invaluable resource for practitioners seeking new and innovative ways to deliver the best possible care to their patients

Patients' Health Related Quality of Life After Coronary Revascularization: A Longitudinal Mixed Method Study

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