Heart failure from ATTRwt amyloid cardiomyopathy is associated with poor prognosis

AIMS: Amyloid cardiomyopathy is an underappreciated cause of morbidity and mortality. Recent evidence suggests that ATTR wild‐type cardiomyopathy (ATTRwt‐CM) is probably much more common than widely appreciated. So far, no data are available on comparison of mortality from ATTRwt‐CM and other heart failure aetiologies. METHODS AND RESULTS: This was a retrospective, observational, cohort study of 2251 patients and their data collected prospectively from May 2000 to June 2018. Long‐term mortality was the main outcome measure. Underlying cardiomyopathies were classified as amyloid CM (6.1%) [ATTRwt 3.0%; light‐chain amyloidosis (AL) 3.1%], dilated CM (dCMP) (46.4%), ischaemic heart disease (IHD) (24.4%), hypertensive heart disease (HHD) (14.6%), hypertrophic CM (HCM) (5.1%), and valvular heart disease (VHD) (3.4%). Median duration of follow‐up was 7.1 years (interquartile range 3.4–11.3). Five‐year overall survival in the whole cohort was 80.1%. In multivariate analysis, individuals with amyloid CM were 3.74 times [95% confidence interval (CI) 2.72–5.14; P < 0.001] more likely to die of any reason than were individuals with dCMP. Mortality was higher in AL‐CM compared with ATTRwt‐CM [hazard ratio (HR) 2.88; 95% CI 1.48–5.58; P = 0.002]. Mortality rates in patients with ATTRwt‐CM were higher than in patients with dCMP (HR 1.96; 95% CI 1.24–3.22; P = 0.007), HCM (HR 2.94; 95% CI 1.28–6.67; P = 0.011), HHD (HR 2.08; 95% CI 1.27–3.45; P = 0.004), VHD (HR 2.38; 95% CI 1.30–4.35; P = 0.005), or left ventricular ejection fraction ≥ 40% (HR 1.99; 95% CI 1.12–3.52; P = 0.018). CONCLUSIONS: Our study demonstrates that amyloid CM is independently associated with poor survival among patients with various causes of heart failure. ATTRwt‐CM had a better long‐term prognosis than did AL‐CM, but was associated with higher mortality than were dCMP, HCM, HHD, VHD, and heart failure with preserved or mid‐range ejection fraction.