1Universitätsklinikum Münster Herz-MRT-Zentrum Münster, Deutschland
Background:
Wild-type transthyretin (TTR) amyloidosis cardiomyopathy (ATTRwt-CM) is a rare, yet life-threatening disease that severely worsens survival and life-quality of affected patients. Tafamidis, a TTR stabilizer that prevents TTR misfolding and thereby decreases amyloidogenesis, is the only approved specific drug for treatment of ATTRwt-CM and may slow down disease progression as well as reduce major adverse cardiovascular events, including cardiovascular mortality. Multi-parametric cardiovascular magnetic resonance imaging (CMR) is the gold standard imaging technique for myocardial functional and tissue characterization, being particularly useful in patients with ATTRwt-CM. The current study aimed to evaluate the impact of tafamidis on cardiac disease progression using multi-parametric CMR in patients with ATTRwt-CM.
Methods:
Our study group comprised N=56 patients with ATTRwt-CM including N=39 patients who were treated with tafamidis (group A) and N=17 tafamidis-naïve patients forming the control group (group B). CMR studies were performed at baseline and after a mean follow-up period of 27 months. Clinical characteristics, serum biomarkers (NT-proBNP, serum troponin) and CMR parameters were carefully assessed. CMR parameters comprised left ventricular (LV) ejection fraction (LVEF), LV mass (LVM), maximal septal wall thickness (IVS), right ventricular ejection fraction (RVEF), native T1- and T2-mapping, extracellular volume fraction (ECV) and LV global/segmental longitudinal strain (LV-GLS). Multi-parametric CMR studies were performed on a 1.5-T MRI machine.
Results:
At baseline, main patient characteristics as well as CMR parameters did not differ significantly between the two groups. During follow-up, there was a significant worsening of essential CMR parameters in both groups, however, with a more pronounced worsening in the tafamidis-naïve group B compared to the tafamidis group A: CMR parameter changes in group A: LVEF (54.2% vs. 46.5%, p = 0.0001), LVM (91.8 g/m2 vs. 96.2 g/m2, p =0.029), IVS (19.0 mm vs. 19.7 mm, p = 0.042), RVEF (54.2% vs 45.8%, p = 0.0001) – and in group B: LVEF (59.9% vs. 53.9%, p = 0.0001), LVM (90.8 g/m2 vs. 102.8 g/m2, p =0.029), IVS (18.8 mm vs. 20.5 mm, p = 0.042), RVEF (57.5% vs. 46.1%, p = 0.0001). Regarding myocardial mapping, LV strain as well as serum NTproBNP, all parameters considerably worsened in both groups, however, again with a more pronounced worsening in the tafamidis-naïve group B: Group A: global T1 (1087 ms vs. 1097 ms, p = 0.04), ECV (54.1% vs. 62.6%, p = 0.0001), LV-GLS (-7.4% vs. -5.2%, p=0.0001) and NTproBNP (1848 vs. 3279, p=0.0001) – compared to group B: (1098 ms vs. 1121 ms, p = 0.04), ECV (46.7% vs. 67.1%, p = 0.0001), LV-GLS (-8.7% vs -5.1%, p=0.0001) and NTproBNP (3716 pg/ml vs. 8769 pg/ml, p=0.0001). Noteworthy, serum troponin values did not change in group A (42.9 pg/ml vs. 42.6 pg/ml, p=0.317) – whereas troponin values considerably increased in group B during follow-up (53.1 pg/ml vs. 80.7 pg/ml, p=0.0001).
Conclusion:
In patients with ATTRwt-CM, tafamidis treatment did not stop the progression of cardiac disease after a mean follow-up period of 27 months – but it slowed down cardiac disease progression based on CMR parameters and serum biomarkers compared to a tafamidis-naïve control group.