Left ventricular strain does not differentiate amyloidogenic profiles in at-risk individuals with TTR Val142Ile

ObjectivesTo identify echocardiographic signatures featuring left ventricular longitudinal strain (LS) associated with genetic risk for cardiac amyloidosis (CA) due to the TTR Val142Ile (V142I) variant in African American (AA) and Hispanic/Latinx (H/L) individuals. BackgroundHereditary transthyretin amyloidosis (hATTR) can cause CA in [~]60-70% of older V142I carriers, but amyloid deposition progresses over many years. Disease-modifying therapy for CA is now available and early initiation is a priority for improving outcomes. Genomic screening programs and familial cascade genetic testing uncover pre-symptomatic V142I carriers, yet no guidelines exist for early CA detection. MethodsExome sequencing data linked to electronic health records (EHRs) of BioMe biobank participants were queried for AA or H/L TTR- and TTR+ (V142I) subjects without hATTR diagnoses and with prior echocardiograms suitable for retrospective LS analysis. Systemic "red flag" features of ATTR were extracted from EHRs of TTR+ subjects. Speckle tracking echocardiography was retrospectively applied to determine global (GLS) and segmental LS. Relative apical sparing (RAS) was calculated. Results57 TTR+ and 46 TTR-age- and ancestry-matched subjects were included. GLS declined with age in females but not males, and was abnormal (<16%) in 18 (31.6%) TTR+ and 7 (15.2%) TTR-subjects (p = 0.066). Apical sparing was observed in 13 (22.8%) TTR+ and 11 (23.9%) TTR-subjects (p = 1.0). After adjusting for relevant demographic and echocardiographic covariates, neither GLS nor RAS was associated with TTR+ V142I status. Red flag features were not associated with GLS or RAS in TTR+ subjects. ConclusionsNeither GLS nor RAS were significantly different between TTR+ and TTR-subjects. Since >50% of TTR+ subjects were [&ge;] 60 years old, penetrance of CA by echocardiography among unselected V142I carriers may be lower than previously estimated. These findings indicate that surveillance for CA in individuals at increased genetic risk due to V142I should not rely solely on echocardiography, even with LS.