Objective: To evaluate N-terminal pro-brain natriuretic peptide (NT-proBNP) as a marker of early pulmonary artery hypertension (PAH) and to study changes in the levels of this marker following treatment with dihydropyridine-type calcium-channel blocker (DTCCB) in patients with systemic sclerosis (SSc).
Methods: We evaluated 40 consecutive SSc patients who had been hospitalized for followup care (mean +/- SD age 56 +/- 11 years and mean +/- SD duration of cutaneous disease 9 +/- 9 years; 27 with limited cutaneous and 13 with diffuse cutaneous disease) but who had no clinical symptoms of heart failure and had a normal left ventricular ejection fraction. At baseline, 10 patients had PAH, defined as a systolic pulmonary artery pressure (sPAP) >40 mm Hg, as measured by echocardiography. Levels of NT-proBNP were determined at baseline (after discontinuation of DTCCB treatment for 72 hours), after taking 3 doses of DTCCB following treatment reinitiation (assessment 1), and after 6-9 months of continuous DTCCB treatment (assessment 2) in the 20 patients who attended regular appointments (including the 10 patients with PAH at baseline).
Results: At baseline, 13 patients had high NT-proBNP values for their ages. High NT-proBNP levels identified patients with PAH with a sensitivity of 90%, a specificity of 90.3%, a positive predictive value of 69.2%, and a negative predictive value of 96%. The NT-proBNP level correlated with the sPAP (r = 0.44; P = 0.006). By assessment 1, the number of patients with PAH and high levels of NT-proBNP had decreased from 9 of 10 to 2 of 10 (P = 0.02). This decrease was partially sustained at assessment 2 (4 of 10 patients; P = 0.06).
Conclusion: NT-proBNP is a useful biologic marker that can be used to diagnose early PAH in SSc patients without clinical heart failure. Measurement of NT-proBNP may be valuable for the evaluation of treatment with DTCCB and vasodilators in patients with PAH.