Optimisation of Surgical Timing in Rheumatic Mitral Valve Disease

Rheumatic heart disease is a consequence of Group A streptococcal infections, and disproportionately affects the world’s most disadvantaged people. Whilst the disease has been essentially eradicated from nonindigenous populations in Australia, Indigenous Australians continue to have some of the highest rates of rheumatic heart disease in the world. The mortality and morbidity associated with rheumatic heart disease primarily results from complications of valvular heart disease which include heart failure and stroke. Valvular surgery can reduce the risk of these, however it comes with its own short-term increase in risk and long-term sequelae. Guidelines for the management of valvular heart disease primarily focus on North American and European populations which are generally older and with mainly single valve disease. Given the unique pathophysiology and demographics of rheumatic valvular disease, this may prove problematic. Rheumatic heart disease is epitomised by progressive mixed and multivalvular disease in children and young adults. Early intervention provides improved long-term outcomes following valvular surgery, especially in young adults. This thesis focuses on surgical delays, screening, and echocardiographic predictors as methods to reduce long-term risk in patients with rheumatic heart disease and optimise timing of tertiary intervention. Chapter 1 reviews the current management of rheumatic heart disease and the pitfalls of existing international guidelines in patients with rheumatic heart disease including current evidence for timing and replacement of valves. Chapter 2 reports on current surgical management of rheumatic heart disease in Australia and compares that to current guidelines. Given most patients come from remote communities, it further looks at delayed referrals and further, delayed surgery for those referred. It illustrates that there are many patients with guideline indications for surgery who fail to be referred or have surgery performed. Chapter 3 examines the prevalence of rheumatic heart disease in Indigenous populations across different regions of South Australia. This provides guidance to the tailoring of screening programs as well as defining the prevalence of echocardiographic confirmed RHD in South Australia. This study shows the prevalence of RHD in remote areas are significantly higher than metropolitan or rural areas. Chapter 4 quantifies sonographer sensitivity and accuracy using the World Heart Federation rheumatic heart disease echocardiographic screening criteria, as well as examining sonographer views of the echocardiographic parameters to enable further refinement of existing criteria. It confirms that sonographers have an extremely high sensitivity and reasonable specificity for RHD screening. Chapter 5 demonstrates the potential role of the left atrium in the management of rheumatic mitral valve disease. It finds that left atrial ejection fraction is the strongest and most reliable predictor for developing a guideline indication for valve intervention in the subsequent two-years. Finally, the insights gained in current management, screening, and echocardiographic assessment are placed in the context of previous literature in Chapter 6, before possible directions for future studies on optimising surgical outcomes and longevity of patients with rheumatic heart disease are discussed in Chapter 7.

Author dc:creator

• Roberts-Thomson, Ross Laurence

Advisors dc:contributor.advisor

• Brown, Alex
• Psaltis, Peter
• Nicholls, Stephen

• Mitral valve
• Surgery
• Rheumatic Heart Disease
• Echocardiography

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/2440/136346

OAI identifier oai:identifier

oai:digital.library.adelaide.edu.au:2440/136346