Prevalence, characteristics and outcomes of older patients with hereditary versus wild-type transthyretin amyloid cardiomyopathy

Background: Transthyretin amyloid cardiomyopathy (ATTR-CM) is often assumed to be associated with wild-type TTR genotype (ATTRwt) in elderly patients (aged >70), some of whom are not offered genetic testing. We sought to estimate the prevalence, clinical characteristics and prognostic implications of TTR variants among elderly patients diagnosed with ATTR-CM. Methods: Data from consecutive patients over 70 years of age diagnosed with ATTR-CM at the UK National Amyloidosis Centre between January 2010 and August 2022 were retrospectively evaluated. All patients underwent clinical evaluation, biochemical tests, echocardiography and TTR genotyping. The study outcome was all-cause mortality. Results: The study population consisted of 2029 patients with ATTR-CM (median age 79 years at diagnosis, 13.2% females, 80.4% Caucasian). Variant ATTR-CM (ATTRv-CM) was diagnosed in 20.7% (n=421) of the study population of whom 329 (76.3%) carried V122I, 49 (11.4%) T60A, 18 (4.2%) V30M and 35 (8.1%) other pathogenic TTR variants. During a median (range) follow up of 29 (12-48) months, ATTRv-CM was associated with increased all-cause mortality compared to ATTRwt-CM, with the poorest survival observed in V122I-associated ATTRv-CM (p<0.001). Univariable and multivariable logistic regression analyses in those with ATTR-CM showed younger age at diagnosis (odds ratio [OR] 0.85 per year, p<0.001), female sex (OR 2.73, p<0.001), Afro-Caribbean ethnicity (OR 65.5, p<0.001), atrial fibrillation (OR 0.65, p=0.015), ischemic heart disease (OR 0.54, p=0.007), peripheral polyneuropathy (OR 5.70, p<0.001) and orthostatic hypotension (OR 6.29, p<0.001) to be independently associated with ATTRv-CM. Conclusion: Up to 20.7% of elderly patients with ATTR-CM have a pathogenic TTR variant. These findings support routine sequencing of the TTR gene in all patients with ATTR-CM regardless of age.