28 The effect of aortic valve replacement on aortic stiffness, assessed using vicorder and 4D-flow MRI, in patients with aortic stenosis

Introduction Aortic stiffness is an important contributor to the increased afterload in aortic stenosis (AS), resulting in adverse cardiac remodelling. It is also an independent predictor of cardiovascular risk and all-cause mortality. There is limited and conflicting evidence on the effect of aortic valve replacement (AVR) on aortic stiffness parameters. The Vicorder device is a cuff-based oscillometric device that measures carotid-femoral pulse wave velocity (cfPWV), which is considered the gold-standard for non-invasive assessment of arterial stiffness. The Vicorder has not been used to measure pulse wave velocity (PWV) in AS patients before. Four-dimensional Flow (4DF) is a novel magnetic resonance imaging (MRI) technique that allows non-invasive measurement of regional pulse wave velocity (PWV) of the aorta. The study aim is to determine the effect of AVR on aortic stiffness parameters using both techniques. Materials and Methods In this single-centre, prospective, observational study, 32 adults (mean age 70.5, 75% male) with severe AS (21 tricuspid aortic valve, 11 bicuspid disease) underwent a Vicorder recording, 4DF-MRI, and a standard echocardiography before and 12-months post-AVR. Stiffness parameters derived from Vicorder and 4DF-MRI were compared between pre- and post-AVR measurements using paired t-tests. P<0.05 was considered statistically significant. Results Patients demonstrated reverse cardiac remodelling post-AVR, with significant reductions in left ventricular volumes and mass (table 1). Matched pre- and post-AVR PWV measurements were available for 26 patients using the Vicorder and 22 patients using 4DF-MRI. Using both the Vicorder device and 4DF-MRI, we found a statistically significant increase in PWV values post-surgery: 8.53±1.52 m/s to 9.57±2.14 m/s (P=0.022) using Vicorder, and from 6.87±2.22 m/s to 9.99±6.91 m/s (P=0.032) using 4DF-MRI (figure 1). Discussion Increase in stiffness post-AVR could be linked to surgical aortotomy-related trauma to the aortic wall integrity or the relief of the stenosed valve unmasking greater vascular load on the aorta. The magnitude of change recorded by 4D Flow MRI was greater than that measured by the Vicorder, which may relate to measurement across different segments of the aorta by the two techniques. Conclusion Aortic stiffness worsened post-AVR, as measured by both techniques. Further studies are required to determine the clinical significance of worsening aortic stiffness post-AVR. Acknowledgements