The role of cardiac magnetic resonance imaging in the assessment of right ventricular function in pulmonary hypertension

McLure, Lindsey Elizabeth Robertson (2015) The role of cardiac magnetic resonance imaging in the assessment of right ventricular function in pulmonary hypertension. MD thesis, University of Glasgow.

Abstract

Pulmonary hypertension (PH) is a rare disease of the pulmonary arteries. It is characterised by vascular proliferation and remodelling resulting in a progressive increase in pulmonary vascular resistance and right ventricular failure. The functional capacity of the right ventricle is the major prognostic determinant in PH, and death usually results from right ventricular failure. Although recent therapeutic advances have improved the short-to-medium term outlook of PH patients, early death due to right ventricular failure remains inevitable in many patients. The imperative role of RV performance in the clinical status and long- term outcome in PH patients is evident. Evaluation of right ventricular function is essential in the management of patients with pulmonary hypertension. Current methods of assessment of PH patients are suboptimal.

The right ventricle is difficult to assess due to its position and geometry. Recent developments in imaging techniques, such as cardiac magnetic resonance (CMR) imaging and echocardiography, have improved our understanding of the structure and function of the right ventricle. Assessment of RV function is complex and no single measurement is generally accepted in clinical practice. The experimental work performed in this thesis aimed to improve our understanding of RV function in PH patients and to provide clarity in the role of CMR in the non-invasive assessment and monitoring of pulmonary hypertension patients.

A non-invasive measurement of stroke volume would be beneficial to monitor disease progression in pulmonary hypertension patients. Chapter 3 demonstrated that cardiac magnetic resonance imaging provided non-invasive measurements of stroke volume that were as accurate as those obtained by thermodilution measured during right heart catheterisation. Inert gas rebreathing using photoacoustic analysis also provided accurate non-invasive measurements of stroke volume. Chapter 4 compared two patient groups: idiopathic pulmonary arterial hypertension (IPAH) and pulmonary hypertension associated with connective tissue disease (CTDPAH). We clarified that there was no significant differences in RV structure and performance between these two distinct patient groups to account for the poorer prognosis in the CTDPAH group.

Treatments for PH are always expensive, sometimes invasive and carry significant side effects. It is imperative that we are able to assess the patient’s response to therapy in a clinically meaningful, accurate and non-invasive manner. The importance of escalating therapy if a patient does not respond to initial treatment has been emphasised in recently published guidelines. Current monitoring techniques have acknowledged limitations and are suboptimal. Chapter 5 presents the results obtained from my contribution to the prospective, longitudinal multinational EURO-MR study. Longitudinal CMR examination identified significant improvements in cardiac function with the introduction of disease-targeted therapy. Baseline and 4 months post therapy CMR scans were compared. It is anticipated that CMR could be a useful monitoring technique for patients with pulmonary hypertension.

• Item Type: Thesis (MD)
• Qualification Level: Doctoral
• Keywords: pulmonary hypertension, cardiac magnetic resonance imaging, right ventricle
• Subjects: R Medicine > R Medicine (General)
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Supervisor's Name: Peacock, Professor Andrew J. and Welsh, Dr. David
• Date of Award: 2015
• Depositing User: Dr Lindsey E R McLure
• Unique ID: glathesis:2015-6884
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 07 Dec 2015 14:24
• Last Modified: 15 Dec 2015 16:40
• URI: https://theses.gla.ac.uk/id/eprint/6884