Unveiling outcomes in coexisting severe aortic stenosis and transthyretin cardiac amyloidosis

Aims: Advances in diagnostic imaging have increased the recognition of coexisting transthyretin cardiac amyloidosis (ATTR-CA) and severe aortic stenosis (AS), with a reported prevalence between 8-16%. In this prospective study, we aimed to evaluate the implications of ATTR-CA on outcomes after transcatheter aortic valve replacement (TAVR).

Methods and results: At two academic centres, we screened patients with severe AS undergoing TAVR for ATTR-CA. Using Kaplan-Meier analysis, we compared survival free from death and a combined endpoint of death and first heart failure hospitalization between patients with and without ATTR-CA. Cox proportional-hazards models were used to determine the association of ATTR-CA with these endpoints. The rate of heart failure hospitalization was compared amongst those with and without ATTR-CA. Overall, 204 patients (83 years, 65% male, Society of Thoracic Surgeons score 6.6%, 72% New York Heart Association class III/IV) were included, 27 (13%) with ATTR-CA. Over a median follow-up of 2.04 years, there was no difference in mortality (log rank, P = 0.99) or the combined endpoint (log rank, P = 0.79) between patients with and without ATTR-CA. In Cox proportional-hazards models, the presence of ATTR-CA was not associated with death. However, patients with ATTR-CA had increased rates of heart failure hospitalization at 1 year (0.372 vs. 0.114 events/person-year, P < 0.004) and 3 years (0.199 vs. 0.111 events/person-year, P = 0.087) following TAVR.

Conclusion: In moderate-risk patients with severe AS undergoing TAVR, there was a 13% prevalence of ATTR-CA, which did not affect mortality. The observed increase in heart failure hospitalization following TAVR in those with ATTR-CA suggests the consequences of the underlying infiltrative myopathy.