Reverse Remodeling Following Valve Replacement in Coexisting Aortic Stenosis and Transthyretin Cardiac Amyloidosis

Abstract

Background: Dual pathology of severe aortic stenosis (AS) and transthyretin cardiac amyloidosis (ATTR) is increasingly recognized. Evolution of symptoms, biomarkers, and myocardial mechanics in AS-ATTR following valve replacement is unknown. We aimed to characterize reverse remodeling in AS-ATTR and compared with lone AS. Methods: Consecutive patients referred for transcatheter aortic valve replacement (TAVR) underwent ATTR screening by blinded 99mTc-DPD bone scintigraphy (Perugini Grade-0 negative, 1-3 increasingly positive) before intervention. ATTR was diagnosed by DPD and absence of monoclonal protein. Reverse remodeling was assessed by comprehensive evaluation before TAVR and at 1 year. Results: One hundred twenty patients (81.8±6.3 years, 51.7% male, 95 lone AS, 25 AS-ATTR) with complete follow-up were studied. At 12 months (interquartile range, 7-17) after TAVR, both groups experienced significant symptomatic improvement by New York Heart Association functional class (both P<0.001). Yet, AS-ATTR remained more symptomatic (New York Heart Association ≥III: 36.0% versus 13.8; P=0.01) with higher residual NT-proBNP (N-terminal pro-brain natriuretic peptide) levels (P<0.001). Remodeling by echocardiography showed left ventricular mass regression only for lone AS (P=0.002) but not AS-ATTR (P=0.5). Global longitudinal strains improved similarly in both groups. Conversely, improvement of regional longitudinal strain showed a base-to-apex gradient in AS-ATTR, whereas all but apical segments improved in lone AS. This led to the development of an apical sparing pattern in AS-ATTR only after TAVR. Conclusions: Patterns of reverse remodeling differ from lone AS to AS-ATTR, with both groups experiencing symptomatic improvement by TAVR. After AS treatment, AS-ATTR transfers into a lone ATTR cardiomyopathy phenotype.