Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Gessner, J.
Hemodynamic responses to orthostatic stress exposition in patients with severe aortic stenosis and coronary artery disease
Humanmedizin; [ Diplomarbeit ] Medizinische Universität Graz; 2022. pp. 94
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Goswami Nandu
- Mächler Heinrich
- Altmetrics:
- Abstract:
- Background: Orthostatic blood pressure dysregulations emerge from autonomic and cardiovascular impairments, which may be present in patients with severe aortic stenosis and coronary artery disease. Orthostatic hypotension has been identified as a predictor of future coronary disease, but hemodynamic studies of postural control in patients with manifest aortic stenosis or coronary artery disease are lacking. Aims and Objectives: This diploma thesis aims to explore the hemodynamic reaction to orthostatic stress in patients with severe aortic stenosis or coronary artery disease as part of the CardioVib trial. We hypothesize that the presence of these cardiovascular conditions impairs orthostatic hemodynamic control, and that differences in the underlying pathologies relay to observable differences in the reaction to orthostatic stress. Methods: A total of 12 patients with coronary artery disease (0 female) and 11 patients with severe aortic stenosis (5 female), enrolled in CardioVib, were subjected to a supine-to-stand test under extensive hemodynamic monitoring using the Task Force® Monitor. Systolic, diastolic, mean blood pressure, heart rate, stroke volume, stroke index, cardiac output, cardiac index, total peripheral resistance and total peripheral resistance index were analysed over the course of the protocol using an epochal structure of eight 10-second intervals. Repeated measures ANOVAs were conducted to assess within group changes over the course of the protocol and a mixed-design ANOVA was performed to assess group differences in the reaction to stand. Hypertensive responders to standing were identified and cardiac index total peripheral resistance index were analysed using a 2x2 mixed-design ANOVA. Results: On average, subjects with aortic stenosis displayed a hypertensive response to standing, with 64% showing overt orthostatic hypertension. In the CAD group no disturbance of the aggregate orthostatic hemodynamic response was observed, but 33% displayed overt orthostatic hypertension, while 17% were deemed hypotensive responders. Significant group differences for cardiac output, total peripheral resistance and total peripheral resistance index existed, yet the reaction to orthostatic stress over the course of the protocol did not differ significantly between groups. The hypertensive response was individually heterogeneously mediated but on average primarily powered by the increase of vascular resistance in the presence of relatively stable cardiac index upon standing. Conclusions: Our findings indicate that orthostatic blood pressure dysregulations may be frequently observed in patients with aforementioned cardiovascular conditions. The reaction to orthostatic stress did not differ between groups, likely due to the high presence of similar orthostatic blood pressure dysregulations in both cohorts. Due to the observational design and several limitations of this analysis, these relationships require more research and ought to be confirmed as well as pathophysiologically explored in future studies.