Heart failure from ATTRwt amyloid cardiomyopathy is associated with poor prognosis

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.

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).

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.