Hyperuricemia as a marker for anaerobic threshold in chronic cardiac failure

Background: Patients with chronic cardiac failure often have elevated plasm a uric acid levels, that are associated to a dismal prognosis. Aim: To inve stigate possible l,metabolic mechanisms to explain elevated uric acid level s in these patients. Patients and methods: Eighteen patients with chronic c ardiac failure aged 61 +/- 10 years old, without gout ol renal failure and not using high closes of diuretics (equal or less than 80 mg/day furosemide or 50 mg/day hydrochlorothiazide) were studied. Plasma uric acid levels we re correlated with anaerobic threshold, maximal oxygen uptake, plasma norad renaline and creatinine and left ventricular ejection fraction, measured ra dioisotopically. Results: Mean maximal oxygen uptake was 16.6 +/- 4.2 ml/kg /min. There was a negative correlation between uric acid levels and maximal oxygen uptake or maximal oxygen uptake/body surface area (r=0.521 and -0.5 33 respectively, p <0.05). Patients with uric acid levels over 7 mg/dl had a lower anaerobic threshold than patients with lower levels (9.81 +/- 2.41 and 13.08 +/- 3.28 ml/kg/min respectively, p <0.05). No significant differe nces in maximal oxygen uptake were observed in these two groups of patients (15.5 +/- 4.24 and 18.08 +/- 3.86 ml/kg/min respectively). Uric acid level s did not correlate with plasma noradrenaline, creatinine or left ventricul ar ejection fraction. Conclusions: These results suggest that a defect in c ellular oxygenation contributes to the elevation of plasma uric acid levels in patients with chronic cardiac failure.