In PROVE-HF (Prospective Study of Biomarkers, Symptom Improvement, and Ventricular Remodeling During Sacubitril/Valsartan Therapy for HF), a prospective, single-group, open-label exploratory study of patients with HFrEF treated with sacubitril-valsartan,66 reduction in NT-proBNP concentration was weakly yet significantly correlated with improvements in markers of cardiac volume and function. Here, NPPB is linked to hydrops fetalis.