Abstract 14291: Novel 4D Procrustes Motion Analysis Applied to CMR Links LMNA Mutation Severity With Myocardial Dynamics

Abstract

Introduction: Procrustes motion analysis (PMA) is a novel method to extract microstructural tensor data from CMR cines. Aim: To illustrate its usefulness in phenotyping patients with confirmed pathogenic lamin ( LMNA ) mutations ( LMNA+). Methods: This n=187 prospective multi-centre CMR study (NCT03860454) recruited LMNA+ (n=67), participants with dilated cardiomyopathy carrying wild-type LMNA gene (DCMwt; n=73) and healthy volunteers (HV, n=47). Left ventricular (LV) cines were analyzed using 3D feature tracking. Generalized procrustes analysis was used to calculate the radial, circumferential, and longitudinal strains. To explore differences in myocardial dynamics between these groups, PMA was employed to derive the procrustes trajectory size at 16 homologous time points of the cardiac cycle in comparison to a common diastolic reference point. Results: Compared to HV, LMNA+ had worse radial and circumferential strain values ( Fig. 1 ). Compared to DCMwt, LMNA + had better strain profiles after adjusting for late gadolinium enhancement. LMNA+ truncating variant carriers had a smaller procrustes trajectory size during diastole compared to splice and missense variant carriers (i.e., reduced myocardial dynamics according to the PMA) ( Fig. 2A ). Similarly, LMNA+ who had a mutation upstream of nuclear localization signal (worse mutation) had lower myocardial dynamics compared to those who had a downstream mutation ( Fig. 2B ). Conclusion: Detailed information on myocardial deformation patterns between diastole and systole can be inferred using PMA applied to CMR cines. Procrustes trajectory size may be a novel marker of myocardial dynamics linked to mutation severity.