Hauser, Jakob Alexander;
(2021)
Development of novel cardiovascular biomarkers by MRI assessment of postprandial physiology.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Stress testing is an important concept in cardiovascular medicine. Feeding is a common cardiovascular stressor. Unlike metabolic or immunological stress, the links between feeding-induced haemodynamic stress and cardiovascular risk and dysfunction have not yet been explored in humans. Therefore, cardiovascular responses to a meal were firstly characterised comprehensively in healthy volunteers using a novel rapid MRI protocol. It was shown that the ingestion of food decreased mesenteric vascular resistance substantially, and that this was compensated for by a rise in cardiac output primarily. Previous research demonstrated that mesenteric vasoreactivity was blunted in obese animals and those on a lipid-rich diet. This was linked to greater myocardial mass, an important and independent risk factor for cardiovascular disease in early life. Therefore, the proposed protocol was conducted in adolescents of varying weight to investigate links between mesenteric vasoreactivity and indicators of cardiovascular risk. Blunted postprandial mesenteric vasoreactivity was associated with raised systolic blood pressure and greater left ventricular mass. Importantly, this was independent of other factors known to influence these variables, such as pubertal stage, obesity, insulin resistance, and resting blood pressure. Abnormal vascular resistance of the limbs and the intestine has been described in Fontan-palliated patients with univentricular congenital heart disease, possibly in order to maintain organ perfusion in the presence of low cardiac output and chronic venous congestion. It was hypothesised that this mechanism could interfere with the common cardiovascular responses to feeding. Using the established protocol, vasoconstriction of the legs, but not the intestine, was found in fasting Fontan patients compared to controls. While the mesenteric responses to the meal were similar, Fontan patients had abnormal responses of the celiac axis and the lower limbs.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Development of novel cardiovascular biomarkers by MRI assessment of postprandial physiology |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2021. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10135456 |
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