Author: Susie Parnham
Parnham, Susie, 2016 Utility of Cardiovascular Magnetic Resonance Ischaemia Assessment of Chronic Kidney Disease and Post Renal Transplant Population, Flinders University, School of Medicine
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Cardiovascular disease is the major cause of death in the chronic kidney disease (CKD) population. Coronary artery disease (CAD) in CKD is often asymptomatic, with multi-vessel ischaemia, and carries a poor prognosis. Although the risk of death is reduced with renal transplantation, cardiovascular disease is still one of the major causes of death post transplant with mechanisms not well defined.
Despite the high prevalence of CAD, current functional cardiac investigations to assess inducible myocardial ischaemia in CKD population are suboptimal and may lead to significant adverse effects. Multi-modality cardiovascular magnetic resonance (CMR) imaging has emerged as a non-invasive clinical tool to assess cardiomyopathy, infarction and viability and myocardial perfusion, without risk of radiation. Stress CMR potentially detects inducible myocardial ischaemia from both epicardial and microvascular CAD. The use of gadolinium contrast is, however, contraindicated in CKD population.
The aim of this thesis is to 1) utilise a non-gadolinium contrast blood oxygen level dependent (BOLD) CMR technique to assess myocardial oxygenation response to stress in the CKD population as a measure of ischaemia and 2) characterise cardiac phenotype in post renal transplant population using non-invasive approaches.
BOLD CMR technique is utilised in Chapter 3 and shows impaired myocardial oxygenation response to stress in CKD population. The reduced BOLD signal intensity in the CKD population could be related to the declining renal function.
Chapter 4 examines the association between myocardial oxygenation response to stress and coronary artery anatomy in the CKD and post renal transplant population.
The study in Chapter 5 demonstrates that myocardial perfusion is impaired in renal transplant population, similar to liver transplant recipients without prior CKD, thus most likely post-transplant related rather than secondary to previous CKD. It utilises stress perfusion CMR and magnetic resonance coronary angiography (MRCA) in renal transplant population with reasonable residual renal function. The impaired myocardial perfusion is independent of the degree of left ventricular hypertrophy and is not fully explained by the presence of significant epicardial CAD, implying microvascular disease.
Chapter 6 investigates the association between reduced myocardial perfusion reserve and aortic stiffness in renal transplant recipients. The study does not show any association between myocardial perfusion reserve and central pulse wave velocity.
Chapter 7 examines blunted myocardial oxygenation response to stress in predicting major cardiac events in asymptomatic people with pre-existing CKD.
This thesis explores the role of CMR in assessing myocardial ischaemia in the renal population. It leads to a potential diagnosis of microvascular disease that has been shown to decrease survival, yet often missed by current clinical cardiac stress investigations. Further research is needed for therapeutic and prognostic study in microvascular coronary artery disease in renal population.
Keywords: Blood Oxygen Level Dependent, Chronic Kidney Disease, Coronary Artery Disease, Liver Transplant, Magnetic Resonance Imaging, Myocardial Ischaemia, Myocardial Oxygenation, Myocardial Perfusion, Pulse Wave Velocity, Renal Transplant
Subject: Medicine thesis
Thesis type: Doctor of Philosophy
Completed: 2016
School: School of Medicine
Supervisor: Prof Joseph Selvanayagam