Abstract 14546: Aortic Stiffness and Its Relationship to Exercise and Ventricular Volumes After Surgical Reconstruction in Single Ventricle Patients Using Real Time Exercise Cardiac Magnetic Resonance
Introduction: Aortic reconstruction (recon) in single ventricle (SV) pts create a stiff large vessel which may adversely impact SV afterload & exercise performance.
Hypothesis: SV pts with recon demonstrate evidence of increased afterload & aortic stiffness correlates with exercise performance.
Methods: SV pts after Fontan were studied with real time exercise CMR & metabolic exercise stress test. Aortic pulse wave velocity (PWV) & distensibility (Dis) of the descending aorta at the level of the diaphragm (DAo) were recorded. Significance was P<0.05.
Results: 18 pts who underwent recon & 30 did not (age median [range] 17.4 [12-42] and 17.0 [12.7-25.6] yrs respectively, P=0.33). PWV was greater in recon than in non-recon (median [range] 4.4 [2.3-9.8] vs 3.6 [2.6-6.3] m/s respectively, P=0.006). Significant inverse correlations in recon were found between PWV and end-diastolic, end-systolic and stroke volumes both at rest and at exercise, presumably because of increased afterload (table). Significant inverse correlations also existed in recon between Dis and exercise parameters such as peak O2 pulse (R=0.56, P=0.02), peak oxygen consumption (R=0.63, P=0.008), oxygen consumption at ventillatory anaerobic threshold (R=0.48, P=0.04) and peak work (R=0.54, P=0.02). See graph. Similar correlations were not seen in those with normal aortas.
Conclusion: SV pts with recon demonstrate increased aortic stiffness, increasing afterload on the ventricle & decreasing ventricular volumes including stroke volume at rest & during exercise. At the same time, native DAo stiffness distal to the reconstruction is inversely correlated with exercise performance, presumably to decrease impedance mismatch, maintaining homogeneity of aortic wall compliance & thus not allowing for wasted energy dissipation. This information suggests SV with recon may be at higher risk for heart failure & may be useful in designing better aortic reconstructions to maximize exercise performance.
Author Disclosures: M.A. Fogel: Research Grant; Modest; NIH RO1, Edwards Life Sciences. E. Kim: None. M. Keller: None. M. Harris: None. K. Whitehead: None. P. Trusty: None. M. Tree: None. A. Wei: None. A. Yoganathan: None.
- © 2016 by American Heart Association, Inc.