Effect of tafamidis therapy on physical function in patients with wild-type transthyretin cardiac amyloidosis

Background: Tafamidis is used as disease-modifying treatment for patients with wild-type transthyretin cardiac amyloidosis (ATTRwt CA). However, the effects of tafamidis on exercise tolerance are unclear.

Methods: This single-center, prospective, observational study aimed to assess the effect of tafamidis on exercise tolerance in 36 patients with ATTRwt CA. Exercise tolerance was evaluated by the peak oxygen uptake (peak VO₂) measured by the cardiopulmonary exercise test (CPX).

Results: The baseline CPX showed a mean anaerobic threshold value of 11.6 ± 2.2 ml/kg/min and peak VO₂ of 15.6 ± 4.1 ml/kg/min. Twenty-eight of the 36 patients underwent a follow-up CPX after 6 months. There was no significant change in peak VO₂ before and 6 months after tafamidis therapy (16.0 ± 4.2 vs. 14.7 ± 4.0 ml/kg/min). The baseline CPX data showed that the mean peak VO₂ was significantly lower in the increased peak VO₂ group than in the non-increased peak VO₂ group (13.7 ± 3.1 vs. 17.7 ± 4.1 ml/kg/min, p = 0.008). A multivariate logistic regression analysis showed that the baseline peak VO₂ value was an independent predictor of improved exercise tolerance by tafamidis therapy (odds ratio: 0.646, 95 % confidence interval: 0.449-0.930, p = 0.019).

Conclusions: Tafamidis prevents deterioration of exercise tolerance in patients with ATTRwt CA. In some patients with ATTRwt CA, exercise tolerance may improve with the use of tafamidis, and those with lower exercise tolerance before tafamidis administration are likely to show improved exercise tolerance.