Abstract 16947: Initial Brain Natriuretic Peptide Levels, but not Hemodynamics, Predict 5-Year Survival in Patients with Pulmonary Arterial Hypertension
Brain natriuretic peptide (BNP) correlates with prognosis in patients with LV dysfunction but its role in Pulmonary Arterial Hypertension (PAH) is unknown outside of short-term data. The strongest predictor of morbidity and mortality in PAH is right ventricular (RV) function. We hypothesized that BNP at the time of referral would predict long-term survival better than hemodynamic parameters or subsequent PAH therapies. We followed a cohort of 72 consecutive patients at our PAH program between 2002 and 2011, that had BNP levels on referral, as well as echocardiography and right heart catheterization, all performed within 24 hours. A subset of these patients (n=27) also had cardiac MRI at the same time. Survival was followed up to five years. We followed a goal-oriented therapy protocol with the 3 classes of approved PAH therapies, adding a class to reach at least 350m in the 6min walk (6MW). The initial BNP levels were not a part of the medical record and were not included in therapeutic decisions. Pearson correlations assessed relationships between parameters and Kaplan Meier Curves compared survival depending on BNP range. BNP correlated with RV mass index, right atrial pressure (RAP) and 6MW (R2=0.588; 0.215, 0.224, p<0.001 for all), but not with mean PAP or PVR index. RV systolic pressure (RVSP) by echocardiography, mean pulmonary arterial pressure (PAPm) and pulmonary vascular resistance (PVR) by catheterization, failed to predict survival, while RAP, WHO class, 6MW and BNP did. In a Cox Regression model BNP was an independent predictor of survival with a hazard ratio of 1.14 (p = 0.03). When patients were divided in two groups, BNP<400pg/mL vs BNP>400pg/mL, cumulative survival at 60 months was 93.1% vs 22.7% respectively, while the 2 groups did not differ in terms of PAP, PVR or type of PAH-therapy. The data suggest that RV fails independently of afterload. The predictive power of initial BNP levels on long-term survival in PAH and its correlation with RV remodeling suggests that RV function upon referral may determine prognosis regardless of PVR and subsequent interventions. BNP could potentially be used to alter clinical care, identifying patients that need earlier referral for transplantation and intensified/accelerated treatment protocols.
- © 2012 by American Heart Association, Inc.