Abstract 19506: The Pulmonary Hypertension Connection Equation Predicts Survival Accurately in a Prospective Population PAH Cohort
Introduction: Contemporary survival in pulmonary arterial hypertension (PAH) is better when compared to the NIH registry, and the NIH equation no longer accurately predicts survival in idiopathic, familial, and anorexigen-associated PAH. We recently developed a new equation, the pulmonary hypertension connection (PHC) equation, based on baseline hemodynamics for predicting survival in patients with idiopathic, familial, and anorexigen-associated PAH. Aim: To validate PHC equation in a combined dataset from PAH drug therapy trials
Methods: We performed an ad hoc analysis in idiopathic and heritable PAH patients (n=449) who were prospectively followed for up to 3.5 years in four double-blind, randomized trial, and their open label extension. We compared the rates of actual survival with predicted survival calculated using the PHC equation [(P(t) = e(-A(x,y,z)t), A(x,y,z) = e((−1.270–0.0148x+0.0402y−0.361z)), where P(t) is probability of survival, t the time interval in years, x the mean pulmonary artery pressure, y the mean right atrial pressure and z the cardiac index] and the NIH equation.
Results: Mean age was 44±15 years, 77% were female, and 80% had WHO functional class III-IV symptoms. The mean six minute walk distance was 354±95 meters. The baseline hemodynamics were: mean right atrial pressure 10±6 mm Hg, mean pulmonary artery pressure 59±15 mm Hg, and cardiac output was 4.1±1.5 L/min. The1-, 2-, and 3-year Kaplan Meier survival rates were 89%, 80%, and 70%, respectively; the non-adjusted survival rates were 91%, 87%, and 84%, respectively. The observed survival was similar to the survival predicted by the PHC equation as opposed to the NIH equation predicted survival (Figure 1).
Conclusions: The PHC equation more accurately predicts survival in a prospective population PAH cohort despite multiple enrollment criteria and disease severity. This equation may be useful for risk estimation in patients with idiopathic and heritable PAH.
- © 2010 by American Heart Association, Inc.