The aim of this study was to evaluate N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with systemic sclerosis (SSc)-associated pulmonary arterial hypertension (PAH) and changes after therapy with bosentan.
Twenty-one patients with SSc-PAH on bosentan therapy were enrolled. PAH was diagnosed by right heart catheterization. NT-proBNP levels, 6-min walking test (6MWT), Doppler echocardiography to estimated systolic pulmonary arterial pressure (sPAP), New York Heart Association (NYHA) functional class for dyspnea and carbon monoxide lung diffusion capacity (DLco) were recorded at baseline, and after 1 and 2 years. Fifty-two SSc patients without PAH were also evaluated as controls.
NT-proBNP plasma levels were significantly higher in SSc-PAH at 385 pg/mL (SD ± 427) than in SSc without PAH and 72 pg/mL (SD ± 52, P < 0.001) at baseline, but did not significantly change following bosentan therapy at 1 year (330 pg/mL [SD ± 291] and 2 years (374 pg/mL [SD ± 291]). However, NYHA class significantly improved at 2 years (P = 0.01) as well as 6MWT (P = 0.04). NT-proBNP levels were positively correlated only with sPAP but not with DLco, NYHA class or 6MWT.
NT-proBNP levels were found to be significantly higher in SSc-PAH at baseline. Serial assessment of NT-proBNP in SSc-PAH patients on bosentan therapy showed no relation to the clinical improvement. This suggests that NT-proBNP may lack 'sensitivity to change', but further studies are warranted to assess the role of NT-proBNP as a biomarker of the therapeutic response in larger cohorts of SSc patients.