Dual pathology in aortic stenosis: Identifying transthyretin amyloidosis likelihood in patients referred for transcatheter aortic valve implantation.

Background: Aortic stenosis (AS) and transthyretin cardiac amyloidosis (CA) may coexist with overlapping clinical and imaging features. Data on the prevalence of this dual pathology (AS-CA) across AS flow groups are limited. This study assessed the likelihood of AS-CA in different AS flow groups and its association with outcomes after transcatheter aortic valve implantation (TAVI). Methods: We retrospectively analyzed 2764 patients (median age 82 years, 55% male) undergoing TAVI for severe native AS between 2017 and 2022). High likelihood of AS-CA was defined as RAISE score ≥ 3 points together with a T-AMYLO score ≥ 3 + red-flag criteria, or a T-AMYLO score ≥ 7 points. Procedural outcomes and long-term survival were evaluated. Results: High AS-CA likelihood was identified in 235 patients (9%). The estimated likelihood was comparable across AS flow groups, including high-gradient (7.4%), classical low-flow low-gradient (10.6%), paradoxical low-flow low-gradient (9.9%), and normal-flow high-gradient AS patients (7.7%) ( Conclusion: Dual pathology of AS-CA is likely present in approximately 9% of TAVI patients and is not confined to specific AS flow groups. Although procedural outcomes are comparable, AS-CA is associated with increased mortality, largely driven by baseline risk. Further studies are needed to improve diagnostic strategies and clarify the underlying mechanisms.