Correlation between serum uric acid level and pulmonary hypertension and pulmonary vascular resistance in children with congenital heart diseases

Background & Objectives: Hyperuricemia occurs frequently in patients with myeloproliferative and lymphoproliferative disorders and in patients with congenital heart disease associated with polycythemia. Since it has been confirmed that serum uric acid levels have a relationship with severity and prognosis of disease, this study was done to evaluate the correlation between serum uric acid level and severity of pulmonary hypertension (PHT).

Materials and Methods:  This cross sectional study was done on 97 hospitalized children (mean age 48.9 months, range 3mo-15yrs) with congenital heart disease   that underwent cardiac catheterization at the Aliasghar hospital between March 2001 and June 2002.

The patients were divided into 2 groups: 42 cases with pulmonary hypertension, and 55cases with normal pulmonary artery pressure (NPAP).

 Results:  Mean (SD) pulmonary arterial pressure in PHT and NPAP groups  were 42.83mmHg (13.08) and 14.89mmHg (3.52), respectively (t=11.18, P<0.001). Mean (SD) serum uric acid levels in PHT and NPAP groups were  4.86mg/dl (2.27) and 4.46mg/dl (l.60), respectively (t=1.01, P=0.31). Mean (SD) ratio of pulmonary vascular resistance to systemic vascular resistance (Rp/Rs) in PHT and NPAP groups were 0.36 (0.18) and 0.11 (0.04), respectively. There was no relationship between serum uric acid levels and pulmonary mean arterial pressure (r=0.03, P<0.81), age (r=0.03, P<0.80), or Hemoglobin (r=0.26, P<0.1).

Discussion: Increased serum uric acid levels had a direct correlation with pulmonary vascular resistance  (r=0.40, P<0.009). We can use this correlation for prediction of severity and progression of disease to Eisenmenger syndrome.