Objectives: Cardiac involvement is an important determinant of prognosis in systemic sclerosis (SSc). The identification of patients with high risk is of great importance. Our aim was to investigate the diagnostic and prognostic value of circulating concentrations of N-terminal fragments of A- and B-type natriuretic peptides (NT-proANP and NT-proBNP) in patients with SSc.
Methods: We prospectively studied 144 patients with SSc and followed them up for five years. Blood was collected for natriuretic peptide measurement at the time of the yearly scheduled cardiological check-up. The occurrence of clinically significant cardiac disease was measured as the composite of pulmonary arterial hypertension, cardiac revascularisation, development of left ventricular dysfunction or death.
Results: Patients diagnosed with heart involvement during the study had significantly higher levels of NT-proANP and NT-proBNP (791.4 ± 379.9 pmol/l vs. 608.0 ± 375.8 pmol/l, p<0.05 and 183.1 ± 162.6 vs. 125.7 ± 117.5 pmol/l, p<0.05, respectively). Receiver-operator-characteristic analysis identified <822.5 pmol/l as the best NT-proANP and <154.5 pmol/l as the best NT-proBNP threshold (sensitivity 56.3%, specificity 79.5%, negative predictive value: 86.4% and sensitivity 50.0%, specificity 76.8%, negative predictive value: 83.7%, respectively). During the follow-up, lower NT-proANP levels were significantly associated with a longer event-free survival (p<0.05), similar but a non-significant trend regarding NT-proBNP levels was also shown (p=0.052).
Conclusions: In our cohort, NT-proANP had a supplementary prognostic value for cardiac involvement in systemic sclerosis. In addition, the high negative predictive value of natriuretic peptides supports the more extensive use in identifying SSc patients with high risk of future cardiac involvement.