Background Pulmonary hypertension (PH) is a severe complication of systemic sclerosis (SSc), affecting 5-12% of patients. Despite recent progress in treatment, prognosis remains poor. Early therapeutic management and goal-oriented approach can improve long-term prognosis. Response to therapy is usually assessed by functional and hemodynamic parameters between 3-6 months after initiation of treatment.
Objectives To compare the changes in NT-proBNP with functional and hemodynamic parameters between baseline and 3-6 months after initiation of therapy.
Methods A retrospective study, undertaken in a National Pulmonary Hypertension Centre, identified patients diagnosed with pre-capillary PH on right heart catheterisation (RHC) (mean pulmonary arterial pressure (mPAP) ≥ 25mmHg and pulmonary capillary wedge pressure (PCWP) ≤ 15mmHg) between January 2006 and August 2012. Patients were included if they had a second RHC between 3 and 6 months after the initial RHC diagnosing PH and if NT-proBNP results were available within 30 days prior to each RHC. 48 patients were identified. 2 patients with glomerular filtration rate < 30 mL/min/1.73m2 were excluded. Changes in variables (Δ) between baseline and 3-6 months were calculated in absolute value, percentage of variation and logarithm of each value. Pearson or Spearman methods were used to estimate correlation coefficient, where appropriate. Patients were divided into two groups: D=“NT-proBNP decreasing” and I/S=“NT-proBNP increasing or stable” according to the difference in NT-proBNP levels between baseline and repeat RHC. Survival analyses were performed using Kaplan-Meier method and log-rank test.
Results 46 patients (40 female and 6 male) were included. 78% had limited cutaneous SSc and 51% were anti-centromere antibody positive. The mean age at diagnosis of PAH was 62.1 ± 11.5 years; the mean time between both RHCs was 3.6 ± 1.0 months and the mean follow-up after first RHC was 28.0 ± 15.4 months. Mean mPAP and PVR (pulmonary vascular resistances) significantly decreased with therapy (ΔmPAP: -3.2mmHg, p<0.001; ΔPVR: -75dynes.s.cm-5, p<0.001), even in the group I/S. PCWP tended to increase in the group I/S (9.9 ± 3.7mmHg at baseline vs 10.9 ± 4.0 after 3-6 months, p=0.072). In the total population, ΔNT-proBNP in absolute value was negatively correlated with Δ6MWD (six minute walking distance) in absolute value (R= -0.362, p=0.017) or percentage (R= -0.525, p<0.001) and with ΔmPAP in percentage (R= -0.327, p=0.027). No correlation was found between ΔNT-proBNP in percentage or in log with PVR, mPAP, cardiac output, cardiac index, venous oxygen saturation, right arterial pressure, PCWP and 6MWD. At 28 months, no difference in survival was found between the two groups (73% in group D and 67% in group I/S).
Conclusions A significant improvement occurred in both hemodynamic parameters and NT-proBNP levels at 3-6 months. However, no strong or clinically relevant correlation was found between RHC or 6MWD and ΔNT-proBNP. Changes in NT-proBNP levels do not seem to be associated with response to therapy or prognosis.
Acknowledgements Dr Vincent Sobanski has received research grants from Association des Sclérodermiques de France, Société Nationale Française de Médecine Interne, Groupe Pasteur-Mutualité, GSK and Institut Servier.
Disclosure of Interest None Declared