Hypoxaemic congenital heart disease (CHD) patients are at higher risk of complications. The aim of this study was to compare and follow-up blood and 24-hour urine analytical data in hypoxaemic and non-hypoxaemic CHD patients.

The inclusion criteria for this study were as follows: patients older than 14 years of age with a structural CHD with or without associated hypoxaemia.

In total, 27 hypoxaemic and 48 non-hypoxaemic CHD patients were included in order to compare blood and 24-hour urine analytical data. Among hypoxaemic patients, 13 (48.1%) were male, two (7.4%) had diabetes mellitus, one of whom was a smoker, one (3.7%) had systemic arterial hypertension, and 11 (40.7%) showed pulmonary arterial hypertension. The mean follow-up time was 3.1±1.9 years. Hypoxaemic CHD patients showed higher proteinuria concentrations (g/24 hours) (0.09 (0.07; 0.46) versus 0.08 (0.07; 0.1), p=0.054) and 24-hour albumin excretion rate (µg/min) (16.5 (11.2; 143.5) versus 4.4 (0.0; 7.6), p<0.001) compared with non-hypoxaemic CHD patients; however, no significant differences were found in the proteinuria levels and in the 24-hour albumin excretion rate in CHD patients with associated hypoxaemia, both at baseline and at follow-up. When divided into groups, hypoxaemic patients with palliative shunts showed significantly higher proteinuria concentrations compared with hypoxaemic patients not operated on or with Fontan procedures (p=0.01). No significant differences were seen in 24-hour proteinuria and 24-hour albumin excretion rate during the follow-up of patients with palliative shunts.

Hypoxaemic CHD patients have significant higher 24-hour proteinuria concentration and 24-hour albumin excretion rate compared with non-hypoxaemic CHD patients. Among hypoxaemic CHD patients, those with palliative shunts showed the highest 24-hour proteinuria concentrations.