Effects Of COPD And Its Treatment On Cardiovascular Structure And Function Assessed Through Advanced Imaging Techniques
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Significant cardiovascular morbidity and mortality exists in chronic obstructive pulmonary disease independent of traditional risk factors. A number of different hypotheses exist to explain this association including the contribution arterial stiffness and lung hyperinflation. Non-invasive cardiovascular imaging and assessment are ideal methods through which this relationship can be further studied although a number of the techniques have yet to be validated in COPD. In this thesis we aimed to achieve a number of goals. First, we aimed to assess the reproducibility and level of agreement between different measures of arterial stiffness in stable hyperinflated COPD. Second, we hoped to establish the utility of 3 different measurement techniques for measuring intrinsic cardiac function in stable hyperinflated COPD. Third, in a case-control study we compared surrogates of cardiovascular risk in hyperinflated COPD patients and a group matched for cardiovascular risk with normal lung function. Finally, we sought to understand the impact of pharmacologically reducing lung hyperinflation on cardiovascular structure, function and arterial stiffness. We have firstly demonstrated that non-invasive measures of arterial stiffness are reproducible in stable hyperinflated COPD. Secondly, we have established the level of agreement and reproducibility of three different CMR techniques for measuring intrinsic myocardial function which will provide important information for the powering of future CMR studies in COPD. Thirdly, we have shown that surrogates for cardiovascular outcomes are adversely affected in COPD compared to a group matched for global cardiovascular risk, suggesting that current scoring systems may be suboptimal in risk prediction in COPD. Finally, we have demonstrated that pharmacological lung deflation has consistent and physiologically plausible beneficial effects on cardiac structure, function and the pulmonary vasculature. Whether intrinsic myocardial function can be modulated through prolonged periods of lung deflation is as yet unverified and should be the focus of future clinical trials.
- Theses