P.49 Aortic Root Longitudinal Strain by Speckle-Tracking Echocardiography: Comparison with Cardiac Magnetic Resonance and Predictive Value in Marfan Syndrome Patients

Background: Low longitudinal strain of the ascending aorta (AAo) by cardiac magnetic resonance (CMR) predicts dilation and aortic events in Marfan syndrome (MFS) [1], possibly reflecting aortic stiffness [2]. Speckle-tracking is established for cardiac deformation, but proximal aorta applications are challenging due to wall thickness and substantial motion. We aimed to validate a purpose-specific speckle-tracking tool for root longitudinal strain analysis by comparison with CMR-derived AAo longitudinal strain and as predictor of dilation in MFS patients. Methods: CMR feature-tracking [1] and echocardiography speckle-tracking where applied to 25 MFS patients free from previous aortic surgery by a single observer blind to clinical data. For echocardiography, two regions of interests were manually created covering both walls in a parasternal long-axis view and tracked along the cardiac cycle. Longitudinal strain was computed as the average of maximum increase in relative distance of several sub-regions covering both walls. Aortic diameter was measured on CMR images. Results: Both techniques were successfully applied to all patients. Aortic root longitudinal strain by echocardiography was linearly related to CMR-derived AAo longitudinal strain (R = 0.573, p = 0.003, Figure A) and was higher (20.4 ± 8.4 vs 10.5 ± 3.8), especially at higher absolute values (Figure B). After a mean follow up of 45 ± 13 months, aortic root diameter growth rate was 0.27 ± 0.3 mm/year. In multivariable analysis corrected for root diameter and heart rate (p = 0.083 and 0.005, respectively), baseline longitudinal strain by echocardiography was independently related to progressive dilation (B = −0.017, p = 0.005). Conclusion: Aortic root longitudinal strain by echocardiography is related to CMR-derived AAo longitudinal strain and is an independent predictor of progressive dilation in MFS patients.