Abstract 12455: Evaluation of N-Terminal Pro-B-type Natriuretic Peptide as a Therapeutic Response Biomarker in Group I Pulmonary Arterial Hypertension

Abstract

Purpose: Goal directed management of left heart failure with an NT-proBNP target-based approach has some evidence of providing a survival benefit. To evaluate the potential utility of serial NT-proBNP measurements for goal-directed therapy in right heart failure we retrospectively assessed NT-proBNP as a predictor for survival in Group I pulmonary arterial hypertension (PAH) patients. Methods: We identified 103 Group I PAH patients from a pulmonary hypertension registry who had baseline elevated NT-proBNP prior to either the initiation or escalation of therapy and at least two serial NT-proBNP measurements. In a two-step process, we (1) estimated baseline NT-proBNP and slope (rate of change of NT-proBNP) with a linear mixed-effects model using all patient data and then (2) compared the power of serial versus single measurements in predicting survival with measured and model-derived values of baseline NT-proBNP with a Receiver Operative Characteristic (ROC) curve analysis . Survival was determined using the Kaplan-Meier methodology. Results: ROC curve analysis revealed significantly higher AUC for model-derived NT-proBNP values compared to the measured values (AUC: for baseline 0.74 vs 0.66, p= 0.009; for slope 0.78 vs 0.66, p= 0.02). Optimal cutpoints for prediction of survival on baseline NT-proBNP were 2012 (measured) vs. 1810 (model-derived) pg/mL. The optimal cutpoint for model-derived change in NT-proBNP was -0.004 log10pg/mL/month. Sensitivity, specificity, and negative predictive values for the three predictor variables were: 64%, 67%, 80% (measured baseline NT-proBNP), 61%, 80%, 81% (model-derived baseline NT-proBNP) and 73%, 57%, 85% (model-derived slope). Conclusions: In PAH patients, serial NT-proBNP measurements better predict survival than single measurements. This retrospective finding reveals that changes in NT-proBNP are associated with overall survival in PAH patients, and set initial target values for a pilot prospective study of NT-proBNP goal-directed therapy.