Urinary Isoxanthopterin in Heart Failure Patients

Background: The prognostic impact of urinary isoxanthopterin (U-IXP), a recently proposed marker of oxidative stress, in patients with heart failure remains unknown. Methods and Results: Patients who were admitted to our institute for decompensated heart failure were prospectively included in the study; U-IXP was measured on admission. The association between the U-IXP concentration and a composite primary outcome that included cardiovascular death and heart failure readmissions following the index discharge was investigated. In all, 42 patients (median age 78 years [interquartile range {IQR} 69–85 years]; 25 males) were included in the study. The median U-IXP concentration on admission was 0.58 μmol/g creatinine (Cre; IQR 0.35–0.95 μmol/g Cre). A higher U-IXP concentration was an independent predictor of the primary outcome adjusted for clinical potential confounders and was associated with a significantly higher cumulative incidence of the primary outcome (71% vs. 16%, P=0.001) at a cut-off of 0.93 μmol/g Cre. Conclusions: U-IXP on admission was associated with cardiovascular death or heart failure readmission following the index discharge in patients with decompensated heart failure. The clinical implication of aggressive interventions to normalize U-IXP and the detailed prognostic mechanism of U-IXP in heart failure patients remain the next concerns.