Objectives: Cardiac involvement is recognised as a poor prognostic factor among systemic sclerosis (SSc) patients, contributing significantly to mortality. We assessed the role of N-TproBNP in SSc-related cardiac involvement in a retrospective cohort of patients.
Methods: Serum N-TproBNP levels were measured in 21 SSc patients with clinically significant cardiac involvement and in a control group of 42 SSc patients without any evidence of heart involvement. All patients had normal pulmonary artery systolic pressure and none had serum creatinine above 140 micromol/L.
Results: Compared with those without cardiac involvement, N-TproBNP was significantly increased in SSc patients with heart involvement (median 11 and 219 pmol/L respectively, p<0.0001; CI 136-445). Receiver operating characteristic curves of N-TproBNP to predict the presence of cardiac involvement in SSc gave a sensitivity of 90.5% at a cut-off level of 50 pmol/L, with a specificity of 97.6%. By logistic regression analysis, N-TproBNP levels of 50 pmol/L were shown to be a strong predictor of heart involvement (OR 78, p<0.001, 95%CI 14-424). Moreover, a significant progressive reduction in N-TproBNP after initial presentation of cardiac involvement was observed in a subset of patients during 6 months of follow-up (p=0.023). Levels of N-TproBNP above the median value of 219 pmol/L did not predict survival (p=0.895, by log-rank). N-TproBNP levels strongly correlated negatively with LVEF (r=-0.7384, p=0.0002).
Conclusions: These data suggest N-TproBNP peptide may be a surrogate marker for cardiac involvement in SSc, selectively identifying patients with severe impairment of cardiac function.