Introduction and objectives: Iodinated contrast agents can block thyroid hormone synthesis. The aims of this study were: 1st) to study the incidence of thyroid function disturbances in children with congenital heart disease after cardiac catheterization, 2nd) to analyze the predisposing factors that may lead to the development of hypothyroidism after angiography, and 3rd) to determine the duration of these hypothyroidism states.
Patients and methods: From february 1993 to April 1997 thyrotropine (TSH) and free thyroxine (FT4) serum values were analyzed before cardiac catheterization and in the two following weeks, in 99 children under three years of age, with congenital cardiac disease. Those patients who showed any postangiography increase in TSH were further evaluated by weekly measures of serum thyroid hormones and TSH until normal values were obtained or until the initiation of hormonal replacement therapy. The patients' data (age, previous exposure to contrast agents, cardiac disease, associated extracardiac malformations, renal failure, severity of illness, treatment) and the catheterism data (the dose and type of contrast and the fluoroscopy time) were included in the univariant analysis.
Results: 10 mUI/ml), that persisted beyond three weeks in six cases. The occurrence of multiple malformation syndromes was the most clearly associated risk factor (p < 0,01) not only in the development of postangiography hypothyroidism but also in longer hormonal dysfunction.
Conclusions: Thyroid function should be tested in every patient with multiple malformation syndrome that undergo angiocardiography with iodinated contrast agents.