Patients were required to have a plasma BNP level of at least 150 pg/ml (or an NT-proBNP level ≥ 600 pg/ml) or, if they had been hospitalized for HF within the previous 12 months, a BNP of at least 100 pg/ml (or an NT-proBNP ≥ 400 pg/ml). Here, NPPB is linked to hydrops fetalis.