Growth differentiation factor-15 in idiopathic pulmonary arterial hypertension

Rationale: Growth-differentiation factor (GDF)-15 is a stress-responsive, transforming growth factor-beta-related cytokine. Circulating levels of GDF-15 provide independent prognostic information in patients with acute pulmonary embolism and chronic left-sided heart failure. Objectives: To assess the prognostic value of GDF-15 in idiopathic pulmonary arterial hypertension. Methods: GDF-15 levels were determined in 76 treatment-naive patients at the time of baseline right heart catheterization. Patients were monitored for a median (range) of 48 (0-101) months (first cohort). Twenty-two additional patients were studied at baseline and 3 to 6 months after initiation of therapy (second cohort). Measurements and Main Results: Fifty-five percent of the patients in the first cohort presented with GDF-15 levels above 1,200 ng/L, the previously defined upper reference limit. The risk of death or transplantation at 3 years was 15 and 44% in patients with GDF-15 levels below or above 1,200 ng/L, respectively (P = 0.006). Elevated levels of GDF-15 were associated with increased mean right atrial and pulmonary capillary wedge pressures, a lower mixed venous oxygen saturation (Sv(O2)), and higher levels of uric acid and N-terminal pro-brain natriuretic peptide (NT-proBNP). After adjustment for hemodynamic and biochemical variables, GDF-15 remained an independent predictor of adverse outcomes (P = 0.002). GDF-15 provided prognostic information in clinically relevant patient subgroups, and added prognostic information to hemodynamic variables and NT-proBNP. Changes in GDF-15 over time in the second cohort were related to changes in NT-proBNP (P = 0.031) and inversely related to changes in Sv(O2) (P < 0.001). Conclusions: GDF-15 is a promising new biomarker in idiopathic pulmonary arterial hypertension.