Abstract
BACKGROUND: There is a paucity of data regarding short-term outcomes and treatment responsiveness of myocardial T1 mapping via cardiac magnetic resonance (CMR) in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) undergoing tafamidis therapy. METHODS: We retrospectively studied 60 wild-type ATTR-CM patients who underwent baseline CMR to measure native myocardial T1 value (T1(native)) and extracellular volume fraction (ECV), followed by tafamidis treatment. Cardiac biomarkers, including high-sensitivity cardiac troponin T and N-terminal pro-B-type natriuretic peptide (NT-proBNP), were measured at baseline. We followed a one-year composite of worsening heart failure (WHF; hospitalization and/or intensification of diuretic therapy for heart failure). Additionally, 51 patients underwent follow-up CMR and measurements of cardiac biomarkers one-year after the initiation of tafamidis treatment. RESULTS: Patients with WHF (n = 12) exhibited significantly elevated baseline T1(native) and ECV than those without WHF, and their optimal cutoffs in predicting WHF were 1447 ms and 48.7 %, respectively. Multivariate analysis adjusted for Mayo or National Amyloidosis Center stages identified T1(native) of ≥ 1447 ms as an independent predictor of WHF, with hazard ratios of 15.2 and 9.3, respectively. A notable proportion of patients exhibited a reduction in T1(native) (39 %) and ECV (47 %) after one year of tafamidis treatment. Post-treatment changes in T1(native) were correlated positively with changes in NT-proBNP concentration (r = 0.40, p = 0.0036). CONCLUSIONS: In wild-type ATTR-CM patients receiving tafamidis, elevated baseline T1 mapping parameters were associated with one-year WHF. T1 mapping parameters, particularly T1(native), may offer imaging-based evidence of alterations in myocardial characteristics induced by tafamidis.