Given the fact that the influential effects of physical exercise and Ang II type 1 (AT1) receptor antagonists on GDF15 and FGF21 [179, 180], whether GDF15 and FGF21 have the potential to evaluate the prognosis of patients with HF treated by angiotensin receptor-neprilysin inhibitor (ARNI) has not yet been determined. This evidence concerns the gene FGF21 and hydrops fetalis.