Hyperuricemia in congenital heart diseases: True or numbers

Background: Uric acid has been shown to be increased in congenital heart diseases (CHD) and Eisenmenger syndrome. The present study was undertaken to investigate the incidence of hyperuricemia, renal dysfunction and the exacerebrating factors in congenital heart diseases (CHD). Methods: We studied prospective cross sectionaly 500 patients, aged one month to 18 years. Blood for serum uric acid, hemoglobin (Hb), hamatocrit (Hct), arterial blood gas (ABG), blood urea nitrogen (BUN), creatinine (Cr) and urinalysis (U/A) as well as pulmonary and aorta arterial pressures were obtained during catheterization. Findings: 24.8% of patients with cyanotic congenital heart diseases (CCHD) had a serum uric acid level of greater than normal, related directly to the degree of polycythemia, but 0.06% in non cyanotic congenital heart diseases. Also 13% of patients with pulmonary hypertension (PH) had hyperuricemia corresponding to PH value. In these groups, hyperuricemia increased parallel to age. 24 % of hyperuricemic cyanotic patients and 10% of hyperuricemic PH had abnormal proteinuria without increased BUN and Cr. Conclusion: Serum uric acid increased proportional to polycythemia and PH in CHD and may cause nephropathy without increase in BUN and Cr.