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.