Risk of iodine-induced thyrotoxicosis after coronary angiography: an investigation in 788 unselected subjects

In this study, the risk of iodine-induced thyrotoxicosis in unselected pati ents from an iodine-deficient area was investigated. The patients were cons ecutively enrolled. Thyroid hormone values and urinary iodine excretion wer e determined before, as well as 1, 4 and 12 weeks after iodine contaminatio n by coronary angiography. Two of 788 unselected patients developed hyperth yroidism within 12 weeks. The two patients did not belong to a risk group f or iodine-induced thyrotoxicosis (i.e. old people, patients with goiter or possible thyroid autonomy, low TSH). Both patients had normal TSH levels at baseline and ultrasound of the thyroid was without evidence of nodules, Th e study shows that in euthyroid unselected patients from an iodine-deficien t area short-term iodine contamination by contrast media rarely leads to hy perthyroidism. On account of these facts, prophylactic therapy, e.g. by per chlorate or thiamazole, is not generally recommended, because the risk of s ide-effects is perhaps even greater than the risk of iodine-induced thyroto xicosis.