Tafamidis improves myocardial longitudinal strain in A97S transthyretin cardiac amyloidosis

Background: Transthyretin cardiomyopathy (ATTR-CM) is a debilitating disease that has received much attention since the emergence of novel treatments. The Transthyretin Cardiomyopathy Clinical Trial showed that tafamidis, a transthyretin tetramer stabilizer, effectively reduced the declines in functional capacity and quality of life. However, Ala97Ser (A97S) hereditary ATTR-CM is underrepresented in major ATTR-CM tafamidis trials.Objectives: We aim to investigate the change in global longitudinal strain (GLS) of A97S ATTR-CM patients after 12 months of tafamidis treatment.Methods: We retrospectively analysed a prospective cohort of patients with A97S ATTR-CM who received tafamidis meglumine (61 mg/day) at the National Taiwan University Hospital. Echocardiography with speckle tracking strain analysis was performed at baseline and 12 months after treatment.Results: In all, 20 patients were included in the cohort. The baseline left ventricular ejection fraction (LVEF) and interventricular septum (IVS) thickness were 59.20 +/- 13.23% and 15.10 +/- 3.43 mm, respectively. After 12 months of tafamidis treatment, the LVEF and IVS were 61.83 +/- 15.60% (p = 0.244) and 14.59 +/- 3.03 mm (p = 0.623), respectively. GLS significantly improved from -12.70 +/- 3.31% to -13.72 +/- 3.17% (p = 0.048), and longitudinal strain (LS) in apical and middle segments significantly improved from -16.05 +/- 4.82% to -17.95 +/- 3.48% (p = 0.039) and -11.89 +/- 4.38% to -13.58 +/- 3.12% (p = 0.039), respectively. Subgroup analysis showed that patients with LVEF < 50% had a better treatment response and improvement in GLS. The patients with an IVS >= 13 mm had an improvement in two-chamber LS from -10.92 +/- 4.25% to -13.15 +/- 3.87% (p = 0.042) and an improvement in apical left ventricular LS from -15.30 +/- 5.35% to -17.82 +/- 3.99% (p = 0.031).Conclusion: Tafamidis significantly improved GLS, and particularly apical and middle LS in A97S ATTR-CM patients.