The American College of Cardology/American Heart Association Heart Failure Staging System Highlights Diagnostic Delay and Predicts Outcome in Transthyretin Cardiac Amyloidosis

Objective: To apply the American College of Cardiology (ACC) and American Heart Association (AHA) heart failure (HF) staging system to patients with transthyretin cardiac amyloidosis (TTR-CA) in order to assess diagnostic delay and evaluate prognosis. Patients and Methods: Consecutive patients with TTR-CA enrolled in an Italian registry were classified according to the ACC/AHA HF staging system at diagnosis. Outcome was assessed as all-cause mortality during a 3-year follow-up. Results: At diagnosis, of 549 patients with TTR-CA, 115 (20.9%) presented with HF stage B, 172 (31.3%) with stage C1, 198 (36.1%) with stage C2, and 64 (11.7%) with stage D. Patients with stages B, C1, C2, and D presented with hierarchically higher prevalence of left ventricular systolic impairment, advanced diastolic dysfunction, advanced New York Heart Association functional class, hospitalization for HF, and N-terminal pro–B-type natriuretic peptide values. At 3 years, the survival rate was 94% in patients with stage B HF, decreasing to 69% with stage C1, 43% with stage C2, and 17% with stage D. At multivariable analysis, considering stage B as the reference, risk increase for all-cause mortality was 4, 5, and 11 for stages C1, C2, and D, respectively. Conclusion: At diagnosis, almost half of patients with TTR-CA present with advanced stages of HF (C2 or D), suggesting marked diagnostic delay. The ACC/AHA HF staging system accurately stratifies prognosis and may be usefully added to the multiparametric evaluation of patients with TTR-CA.