1-034 Viscous energy losses in the ascending aortas of patients with bicuspid aortic valves with and without aortic stenosis

Introduction Mechanical energy losses in the thoracic aorta are thought to be associated with aberrant aortic flow patterns in the presence of aortic valvular disease. The aim of this study was to compare viscous energy losses in the aortas of subjects with bicuspid aortic valves, both with (AS-BAV) and without (BAV) aortic valve stenosis (AS), as well as those with trileaflet aortic valves (TAV) without AS. Methods Twenty-eight prospectively recruited subjects comprising AS-BAV (n=11) BAV (n=8) and TAV (n=9) underwent four-dimensional flow cardiac magnetic resonance imaging (4DF-CMR). Due to inadequate image quality for one AS-BAV patient, 10 subjects with AS-BAV were included in the analysis. Peak systolic and diastolic viscous energy losses were measured between the aortic root reference plane and the mid-ascending aorta (MAAo) and proximal aortic arch (PAA) anatomical planes using Circle Cardiovascular Imaging. Statistical analysis was conducted using ANCOVA, adjusting for age and diastolic blood pressure. Results At the MAAo, systolic and diastolic viscous energy losses were significantly higher in AS-BAV and BAV compared with TAV (table 1). A similar pattern was observed at the PAA, in AS-BAV and BAV compared with TAV. Differences between AS-BAV and BAV patients were significant only during diastole. Conclusion BAV, both with and without AS is significantly associated with greater viscous energy losses in the mid-ascending aorta and proximal aortic arch. Therefore, viscous energy losses derived from 4DF-CMR may serve as a sensitive biomarker for quantifying pathological aortic haemodynamic patterns in BAV disease. Increased aortic viscous energy losses suggest that BAV morphology contributes to a significant increase in ventricular afterload even before the onset of AS, which may have implications for monitoring and timing of valvular interventions.