Novel assessment of cardiorespiratory interactions in aortic stenosis

The outcome in aortic stenosis (AS) depends on the correct timing of aortic valve replacement. Currently, this is based on symptoms and cardiac response to pressure overload. In patients with multiple medical conditions, uncertainty exists concerning their symptomatic onset and in distinguishing cardiac from respiratory causes of breathlessness. An accurate assessment of lung disease and optimal tools to discriminate between cardiac and respiratory dyspnoea are needed in AS, in whom decompensation may confound respiratory assessment, and conversely, chronic obstructive pulmonary disease (COPD) is a major reason for delay or avoidance of surgery. Advanced imaging allows the assessment of cardiac and respiratory co-morbidities, potentially reducing the misinterpretation of symptoms, and, therefore, may enable more appropriate treatment in cardiopulmonary disease. The thesis explores the importance of lung disease in AS and the limitations of standard respiratory assessment in decompensated cardiac disease. Secondly, novel ways of discriminating between respiratory and cardiac effects in AS are assessed. Lastly, the importance of the right ventricular response to pressure overload is evaluated. In summary, this thesis demonstrates the role of cardiorespiratory assessment in cardiac disease, including novel morpho-functional imaging evaluation of the cardiopulmonary interactions in AS. Patients with advanced lung disease who would not improve after valve replacement may in the future avoid a high-risk futile intervention. On the contrary, those with a hyperdynamic right ventricle and apparent respiratory dysfunction determined by cardiac disease might avoid cardiac under-treatment.