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

Abstract

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.