Outcome and Disease Progression in NYHA Functional Class I and II Patients With Wild-Type Transthyretin Cardiomyopathy Treated With Tafamidis

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) is a progressive infiltrative cardiomyopathy. Tafamidis improves survival and functional outcomes, especially in early-stage disease, but predictors of progression under treatment remain unclear. This multicenter observational study included 683 patients with NYHA class I–II ATTRwt-CM treated with tafamidis across 19 Italian centers. Baseline characteristics and 12-month changes in clinical, biochemical, and imaging parameters were analyzed. The primary endpoint was a composite of all-cause death or heart failure (HF) hospitalization. Over a median 18-month follow-up, 15% of patients reached the primary endpoint (9% within 12 months). Baseline NAC/Mondor stage III and loop diuretic dose >0.35 mg/kg were independently associated with adverse outcomes. Within 12 months, up to one-third showed markers of disease progression. Worsening in NYHA functional class, NAC/Mondor stage, NT-proBNP, eGFR, and outpatient diuretic intensification predicted subsequent HF events or death, whereas imaging parameters were not prognostic. Two models based on clinical or biochemical progression showed similar predictive accuracy (C-statistic ≈0.72). Despite tafamidis therapy, early-stage ATTRwt-CM patients may experience clinical deterioration within 12 months. Baseline disease stage, diuretic requirement, and worsening in clinical or biochemical parameters identify individuals at higher risk, supporting their use in routine monitoring and as potential endpoints in future studies.