Background and study objective: Cardiac involvement, a common and often fatal complication of systemic sclerosis (SSc), is currently detected by standard echocardiography enhanced by tissue-Doppler echocardiography (TDE). We examined the performance of the biomarker of cardiovascular disease, N-terminal brain natriuretic peptide (NT-proBNP), in the detection of cardiac involvement by SSc.
Methods: We prospectively studied 69 consecutive patients suffering from SSc (mean age = 56±13 years, 56 women) with standard echocardiography and TDE measurements of longitudinal mitral and tricuspid annular velocities. Plasma NT-proBNP was measured in all patients.
Results: Overall, 18 patients had manifestations of cardiac involvement, of whom 7 had depressed left ventricular and 8 depressed right ventricular myocardial contractility, and 8 had elevated systolic pulmonary arterial pressure. Patients with reduced contractility had increased mean NT-proBNP (704±878 pg/ml versus 118±112 pg/ml in patients with normal myocardial contractility, p<0.0001). Similarly, NT-proBNP was higher in patients with (607±758 pg/ml) than in patients without (96±78 pg/ml) manifestations of overall cardiac involvement (p<0.0001). Receiver-operating-characteristics analysis shows that NT-proBNP reliably detected depressed myocardial contractility and overall cardiac involvement (area under the curve 0.905[0.814-0.996] and 0.935 [0.871-0.996] respectively). Considering SSc patients with normal echocardiography and TDE as controls, and using a 125pg/ml cut-off concentration, sensitivity and specificity were 92% and 71% in the detection of depressed myocardial contractility, and 94% and 78% for overall cardiac involvement.
Conclusions: NT-proBNP reliably detected the presence of cardiac involvement and appears as a very useful marker to risk stratify patients presenting with SSc.