Time‐dependent changes in plasma xanthine oxidoreductase during hospitalization of acute heart failure

AIMS The aim of present study is to evaluate the clinical significance of the time-dependent changes in xanthine oxidoreductase (XOR) activity during hospitalization for acute heart failure (AHF). METHODS AND RESULTS A total of 229 AHF patients who visited to emergency room were prospectively enrolled, and 187 patients were analysed. Blood samples were collected within 15 min of admission (Day 1), after 48-72 h (Day 3), and between Days 7 and 21 (Day 14). The AHF patients were divided into two groups according to the XOR activity on Day 1: the high-XOR group (≥100 pmol/h/mL, n = 85) and the low-XOR group (<100 pmol/h/mL, n = 102). The high-XOR patients were assigned to two groups according to the rate of change in XOR from Day 1 to Day 14: the decreased group (≥50% decrease; n = 70) and the non-decreased group (<50% decrease; n = 15). The plasma XOR activity significantly decreased on Days 3 and 14 [23.6 (9.1 to 63.1) pmol/h/mL and 32.5 (10.2 to 87.8) pmol/h/mL, respectively] in comparison with Day 1 [78.5 (16.9 to 340.5) pmol/h/mL]. A Kaplan-Meier curve indicated that the prognosis, including heart failure (HF) events (all-cause death and readmission by HF) within 365 days, was significantly poorer in the low-XOR patients than in the high-XOR patients and was also significantly poorer in the non-decreased group than in the decreased group. CONCLUSIONS The plasma XOR activity was rapidly decreased by the appropriate treatment of AHF. Although high-XOR activity on admission was not associated with increased HF events in AHF, high-XOR activity that was not sufficiently reduced during appropriate treatment was associated with increased HF events.