Abstract 6167: Appropriate Timing Enhances the Utility of Plasma Brain Natriuretic Peptide in Predicting Survival in Pulmonary Arterial Hypertension
Background: The natural course of pulmonary arterial hypertension (PAH) is characterized by progressive functional worsening leading to right heart failure and death. Since plasma brain natriuretic peptide (BNP) levels correlate with right ventricular dysfunction, we sought to evaluate the use of BNP as a prognostic indicator in PAH.
Methods and Results: We examined our prospective pulmonary hypertension registry for patients who underwent right heart catheterization (RHC) between 1998 and 2008. The BNP values from the time of catheterization until date of last visit or death were analyzed in relationship to overall survival. Of the 626 patients who underwent RHC, 559 met the Venice classification of PAH: 83% category I, 10% category III, 5% category IV, and 2 % category V. Baseline mean pulmonary artery pressures were 47±16 mm Hg and cardiac index 2.6±1 l/min/m2. During follow up, patients were treated with prostanoids (27%), endothelin blockers (31%), PDE5 inhibitors (40%), calcium channel blockers (2%), and 56% received combination therapy. BNP values during the first 6 months were higher in patients who died in the first 2 years (n=108) compared to patients surviving more than 5 years (n=82) but the levels had no correlation to survival [R2=0.03, p=0.2]. Interestingly, the strongest predictor for survival was the BNP level obtained 12–14 months from RHC [R2=0.7, p=0.0001]. All patients who survived over 5 years had BNP value less than 150 ng/L at 12 months and all patients with BNP values >330 ng/L at 12 months were dead by 2 years. Furthermore, there was an accelerated rate of increase in BNP levels in patients who did not survive past 2 years [BNP rise rate (ng/L/month): non- survivors 33 ± 14 while, long-term survivors 0.3 ± 1; p=0.008].
Conclusions: In patients with pulmonary arterial hypertension, initial BNP levels do not appear to have prognostic significance. BNP levels at 1 year, however, are strong predictors of early mortality or long term survival. The rate of rise in BNP levels is a novel concept that may be a useful management tool before the 1 year time point.