Brain natriuretic peptide (BNP) is a cardiac hormone secreted by cardiomyocytes in response to ventricular wall stretch. It counteracts the renin–angiotensin–aldosterone and sympathetic nervous systems by inducing vasodilation, diuresis and natriuresis. BNP has been widely used as a marker of ventricular dysfunction1 2 and was found to be predictive of survival in congestive heart failure3 and idiopathic pulmonary arterial hypertension (PAH).4

In this issue, Diller et al report on their retrospective analysis of a large Eisenmenger population (181 patients) undergoing plasma BNP measurements as part of their routine clinical assessment.5 They found that BNP concentrations were increased in these patients and that elevated BNP concentrations were predictive of morbidity and all-cause mortality independent of Down's syndrome, renal function and 6 min walk test distance. They also observed that treatment of Eisenmenger patients with disease targeting therapies was associated with a significant reduction in BNP concentrations.

Although BNP concentrations have often been used to guide therapy in heart failure,6 few data are available in the setting of PAH.7 8 The conclusions of Diller et al are appealing and support previous studies indicating that targeting therapies are associated with a reduction in BNP concentrations in PAH.

Eisenmenger syndrome is a complex pathological condition that can affect multiple organs, whose function progressively deteriorates over time. In this respect, BNP is just one among the many key features that should be taken into account for clinical decision making in such a …