Efficacy of perioperative oral triiodothyronine replacement therapy in patients undergoing off-pump coronary artery bypass grafting

Objective: The aim of this study was to assess the effects of oral triiodothyronine (T₃) therapy on postoperative thyroid hormone concentrations, hemodynamic variables, and outcomes. Design: A prospective, randomized, controlled, double-blind study. Setting: Cardiac operating room at a single institution. Participants: One hundred patients undergoing elective off-pump coronary artery bypass graft surgery. Interventions: Patients received either 20 μg of oral T₃ or placebo every 12 hours starting 20 minutes before anesthetic induction, for a total of 4 doses. Measurements and Main Results: Plasma concentrations of thyroid hormones were measured serially before surgery, upon arrival in the intensive care unit, and 12, 24, and 36 hours after surgery. Hemodynamic variables also were recorded serially. Postoperative inotrope requirement and major morbidity endpoints were assessed. Serum T₃ concentrations were significantly higher with fewer patients having T₃ concentrations below the normal range in the T₃ group than the placebo group throughout the postoperative period. Hemodynamic variables, postoperative inotrope requirement, and outcome variables showed no differences between the groups. Conclusions: Oral T₃ therapy significantly attenuated the postoperative decline in T₃ concentrations in patients undergoing off-pump coronary artery bypass graft surgery. The lack of apparent clinical benefit merits further investigations in patients with reduced cardiac performance.