NPPB and pulmonary arterial hypertension: Moreover, studies have shown that plasma levels of BNP are proportional to the extent of RV dysfunction in pulmonary hypertension (Nagaya et al., 1998), and it was suggested that increased levels of BNP should be considered by cardiologists as an indication of a high risk of RV dysfunction (Mariano-Goulart et al., 2003).