Presentation: Brain Natriuretic Peptide and Uric Acid as Predictors of Pulmonary Arterial Hypertension in Patients with Systemic Sclerosis (2007)

16 Brain Natriuretic Peptide and Uric Acid as Predictors of Pulmonary Arterial Hypertension in Patients with Systemic Sclerosis

PURPOSE: Brain Natriuretic Peptide (BNP) is a hormone released by the left and right ventricles in response to stretching, and has been found to be a useful predictor in patients with ventricular failure. Uric acid levels have been reported to correlate with pulmonary artery pressures in patients with idiopathic pulmonary arterial hypertension (PAH). We sought to determine whether BNP and uric acid levels predict the pulmonary hemodynamic parameters obtained by right heart catheterization (RHC) in patients with Systemic Sclerosis (SSc).
METHODS: Thirty-seven SSc patients seen in the rheumatology and cardiology clinics from 2001 to 2006 with an ICD 9 code 710.1, who had undergone RHC and had uric acid and BNP levels checked within 3 months of RHC were identified. Demographic and clinical data was recorded. Thirty-three were eligible for the uric acid and twenty-nine for the BNP analysis. The BNP levels needed to be log-transformed to achieve a normal distribution. A regression analysis between the BNP and uric acid levels with the pulmonary hemodynamic parameters obtained by RHC was performed. Patients with chronic kidney disease (glomerular filtration rate of less than 30 cc/min) or left heart failure were excluded from the BNP analysis. PAH was defined as a mean pulmonary arterial pressure of 25 mmHg or more. Differences between the groups mean with and without PAH with respect to the BNP and uric acid levels were also examined.
RESULTS: The mean age of the 37 patients was 59.5 ± 13.1 years (mean ± SD). Thirty-four patients were female (91.9%), twenty-two were Caucasians (59.5%) and fifteen were African-American (40.5%). Eighteen patients had limited form of SSc (48.6%), nine patients a diffuse form (24.3%), three had an overlap (8.1%), and seven were undetermined (18.9%). Twenty-five patients (67.6%) who had RHC were found to have PAH. SSc patients with PAH had significantly higher logBNP (2.22 ± 0.72 versus 1.57 ± 0.39, p=0.0134) and uric acid (7.4 ± 2.4 versus 4.8 ± 1.9, p= 0.0047) levels than those without PAH. Significant linear relationships were found between both the logBNP and uric acid concentrations with the mean pulmonary vascular resistance (r2 =0.38, p=0.0003 and r2 =0.39, p=0.0001, respectively). Comparing the logBNP and the uric acid concentrations against all the pulmonary hemodynamic parameters also yielded similar significant regression coefficients.
CONCLUSIONS: The BNP and uric acid were found to be good predictors of the pulmonary hemodynamic parameters in patients with SSc. Additional studies are necessary to determine if these non-invasive tests will be useful diagnostic or prognostic tools that should be incorporated into clinical practice.

 A. Gaffo, None; R. Benza, None; B.J. Fessler, None.