[Coronary artery bypass surgery in a patient with Basedow's disease controlled in hypothyroid state]

Coronary artery bypass surgery was performed in 55-year-old male with angina pectoris and Basedow's disease. His thyroid function was controlled in hypothyroid state, in order to avoid thyroid crisis perioperatively. At the start of the extra-corporeal circulation (ECC), values of T4, free-T4, T3 and free-T3 decreased progressively below the lower limits and remained depressed during ECC. The values returned almost to the pre-ECC levels at 2 hours after ECC. However, thereafter a gradual fall was seen up to 3 days after ECC. On the other hand, postoperative concentration of reverse-T3 progressively increased. Perioperative course was uneventful. The patient remains free of angina pectoris with optimal anti-thyroid drug therapy.