P896Effects of tafamidis in patients with transthyretin amyloid cardiomyopathy

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Abstract Background Transthyretin amyloid cardiomyopathy (ATTR-CA) is caused by deposition of amyloid fibrils in the myocardium. The deposition occurs when transthyretin (TTR) becomes unstable and misfolds. Tafamidis is a kinetic stabilizer of TTR that prevents tetramer dissociation and amyloidogenesis by TTR. Methods Eighteen patients with diagnosis of ATTR-CA (hATTR or wtATTR) from our national amyloidosis registry were treated with 20 mg of tafamidis for a period of six months. In our explorative analysis we aimed to evaluate the effects of tafamdis by changes from baseline of the serum NT-proBNP concentration, 6-minute walking distance, as well as cardiac structure and function. Results The exploratory analysis showed a decrease in serum NT-proBNP concentration in tafamidis treated patients, compared to increase in untreated patients (median difference, −481.0 pg/mL). Tafamidis improved the walking distance during the 6-minute walk test at month six, compared to baseline (mean, 31.25 m). Echocardiographic findings revealed an improvement of the global longitudinal strain (mean, 0.77%), a decrease in left atrial size (mean, −1.65 mm) and a decrease in left ventricular size (mean, −4.13 mm) in tafamidis treated patients compared to untreated patients. Due to insufficient power the results did not differ significantly between tafamidis treated patients and untreated patients. Change from baseline Tafamidis No treatment Treatment Difference p-value Cardiac Biomarkers n=18 n=15 NT-proBNP, ng/L Baseline, median 2740.0 2835.0 CFB to 6 months, median −207.0 274.0 −481.0 0.329 Functional Status n=8 n=7 6MWT, m Baseline, mean 441.00 420.50 CFB to 6 months, mean 31.25 −16.50 +47.75 0.373 Echocardiogram n=17 n=15 LA, mm Baseline, mean 63.41 61.33 CFB to 6 months, mean −1.65 0.60 −2.25 LV, mm Baseline, mean 44.13 41.80 CFB to 6 months, mean −4.13 0.33 −4.46 0.075 LV wall thickness, mm Baseline, mean 22.06 18.47 CFB to 6 months, mean 0.68 −0.60 +1.28 0.055 Longitudinal strain, % Baseline, mean −10.66 −12.42 CFB to 6 months, mean 0.77 −1.03 +1.80 0.652 MRI n=7 n=6 ECV, % Baseline, mean 52.26 44.22 CFB to 6 months, mean 0.81 3.70 − 2.89 0.493 LV mass, g Baseline, mean 187.71 170.33 CFB to 6 months, mean 24.29 19,67 +4.62 0.612 Conclusion Treatment with tafamidis for a period of six months in patients with ATTR-CA leads to positive effects on NT-proBNP level, 6-minute walking distance, as well as cardiac structure and function compared to untreated patients.