Associations of circulating natriuretic peptides with haemodynamics in precapillary pulmonary hypertension

While N-terminal B-type natriuretic peptide (NT-proBNP) has been examined extensively in pulmonary hypertension (PH), limited data exists on the subtype A, C and D. The aim of this prospective pilot study was a head-to-head comparison of NPs in respect to haemodynamic parameters and the influence of renal function.

Plasma samples were drawn during routine right heart catheterization in 62 patients with precapillary PH and 20 control patients. MR-proANP measurements were performed on the automated Kryptor platform, NT-proBNP by CLIA, NT-proCNP and DNP levels by ELISA. Results are expressed as median [range] and tested non-parametrically. Non-parametric locally linear multiple regression was performed to determine the influence of renal function on NP levels. P-values <0.05 were considered significant.

Patients with PH had significantly higher MR-proANP and NT-proBNP levels. NT-proCNP showed a trend to higher levels, while DNP did not differ from control subjects. Both MR-proANP and NT-proBNP were associated with cardiac index (CI), right atrial pressure (RAP), mean pulmonary artery pressure (PAPm) and pulmonary vascular resistance index (PVRI). NT-proCNP was associated with RAP, while DNP showed no associations with haemodynamic variables. Associations of haemodynamic parameters with NPs were weakened in patients with in elevated serum creatinine and showed increased regression slopes.

MR-proANP demonstrated equivalent associations with haemodynamics compared to NT-proBNP, but both markers depend on intact renal function. NT-proCNP was correlated with RAP and renal function, while DNP showed no associations. Larger studies should evaluate MR-proANP as candidate prognostic biomarker in PH.