NPPB and hydrops fetalis: Circulating levels of these peptides are substantially increased in people with heart failure (HF) and during acute coronary syndromes and are established biomarkers for diagnosis, prognosis, and management in patients with HF and cardiovascular disease (CVD).2–4 Moreover, prospective epidemiologic studies have shown that elevated NT-proBNP is associated with increased CVD risk in the general population.5–7