Enalapril in paediatric patients with Alport syndrome: 2 years' experience

Abstract

Enalapril, a long-acting inhibitor of angiotensin-converting enzyme, was given for 2 years to seven children with Alport syndrome. Five patients had a classical X-linked form of the disease; two siblings had the autosomal recessive variant. Their age was between 5.15 and 13.75 years when enalapril was started. All patients had haematuria and proteinuria, creatinine clearance was >80 ml/min per 1.73 m² in all, and only one patient was hypertensive. The starting dose of enalapril (0.1 mg/kg body weight per day) was increased progressively according to individual clinical tolerance. The median doses were 0.13, 0.12, 0.21 and 0.29 mg/kg at 6, 12, 18 and 24 months, respectively. Median values of mean blood pressure were 95 mmHg at the start and 84 mmHg after 24 months. Median daily proteinuria decreased from 52 mg/kg to 18 mg/kg at 6 months, 21 mg/kg at 12 months, 12 mg/kg at 18 months and 30 mg/kg at 24 months. Serum creatinine increased over time from a median of 0.64 mg/dl at baseline to 0.77 mg/dl at 24 months. Concomitantly, there was a decrease in GFR from 104 to 83 ml/min per 1.73 m² at 18 months and an increase again to 95 ml/min per 1.73 m² at 24 months. Analysis of the individual data showed three patterns: no response (n=2), temporary response (n=2) and sustained response (n=3).

Conclusion When given enalapril at the dosages mentioned, Alport patients as a group display a marked reduction in urinary protein excretion with a nadir of 23% of the baseline figure at 18 months, a decrease that cannot be accounted for by the slight decrease in glomerular filtration rate. Although these are preliminary data, it is recommended to try an angiotensin-converting enzyme inhibitor in every paediatric Alport patient with proteinuria.