Tafamidis slowed cardiac remodeling and potentially lowers amyloid deposition in patients with hereditary A97S transthyretin cardiomyopathy in a recent study.
Transthyretin amyloid cardiomyopathy (ATTR-CM) is a rare but life-threatening disease. Tafamidis decreases amyloid formation and is an effective treatment for ATTR-CM. There are differences in the level of cardiac involvement among disease variants. Up to 82.1% of patients with the A97S hereditary type of ATTR amyloidosis suffer cardiac involvement. Despite this, only limited research is available regarding the effects of tafamidis on cardiac remodeling in this population.
A study in the Orphanet Journal of Rare Diseases evaluated the effectiveness of tafamidis in hereditary A97S ATTR-CM patients.
The study comprised 14 hereditary A97S ATTR-CM patients and 17 healthy controls. Tafamidis was well tolerated by all patients. Baseline characteristics were similar between the subjects in both groups. More ATTR-CM patients had significantly higher N-terminal pro-B-type natriuretic peptide (NT-proBNP), a worse New York Heart Association (NYHA) functional class, and greater left ventricular (LV) anterior and posterior wall thickness than controls.
Significantly Lower LV Ejection Fraction (Lvef) in Attr-Cm Patients
Cardiac magnetic resonance (CMR) imaging demonstrated a significantly lower LV ejection fraction (LVEF) in ATTR-CM patients than in controls (54.1% vs. 69.3%, P<0.001). ATTR-CM patients had significantly higher LV end-systolic volume index (LVESVi) (32.3 vs.19.9 ml/m2, P=0.001), LV mass index (LVMi) (93.0 vs. 52.3, P<0.001), native T1 mapping (1159.5 vs. 1020.8 ms, P<0.001), and extracellular volume (ECV) (51.5% vs. 26.1%, P<0.001) than controls. ATTR-CM patients also showed significantly lower global radial strain (GRS) (19.2 vs. 36.3, P<0.001) and significantly higher global circumferential strain (GCS) (-12.6 vs. -19.7, P<0.001) and global longitudinal strain (GLS) (-8.7 vs. -17.2, P<0.001) than controls.
CMR Parameters for Predicting ATTR-CM
ECV had the highest area under the curve (AUC, 0.982) among all CMR parameters for predicting the presence of ATTR-CM in receiver operating characteristic (ROC) curve analysis. The AUCs of other CMR parameters were as follows: LVEF, 0.857; LV end-diastolic volume index (LVEDVi), 0.669; LVESVi, 0.824; LVMi, 0.890; GRS, 0.879; GCS, 0.860; GLS, 0.923; and native T1 mapping, 0.974.
Tafamidis Therapy Showed Significant New York Heart Association Functional Improvement
After one year of tafamidis therapy, 21% of patients showed significant improvement in their New York Heart Association (NYHA) functional status scores. Significant improvement was also observed in prealbumin (transthyretin) levels (available for six patients) after tafamidis treatment (27.1 to 32 mg/dL, P=0.046). NT-proBNP level also improved from 2078.1 to 1133.4 pg/ml, but the improvement was not statistically significant. Among the CMR parameters, ECV showed a subtle but statistically significant decrease (51.5 to 49, P=0.041) after one year of tafamidis treatment. Meanwhile, no change was observed in LVEF, LVEDVi, LVESVi, LVMi, GRS, GCS, GLS, and native T1 mapping.
These findings highlight the potential of tafamidis to reverse cardiac remodeling in A97S hereditary ATTR-CM patients by decreasing the progression rate of cardiac remodeling and lowering amyloid deposition.
Tsai, C. H., Chao, C., Hsieh, S., Yu, A., Wu, Y. W., Cheng, M., Lee, M., Chou, C., Shun, C., Hsueh, H., Juang, J. J., Tseng, P., Su, M., & Lin, Y. (2023). Tafamidis decreased cardiac amyloidosis deposition in patients with Ala97Ser hereditary transthyretin cardiomyopathy: a 12-month follow-up cohort study. Orphanet Journal of Rare Diseases, 18(1). https://doi.org/10.1186/s13023-023-02824-0