Oral Thyroid Hormone Pretreatment in Left Ventricular Dysfunction

Objective: The aim of the present study was to determine whether pretreatment with oral thyroid hormone had beneficial effects in cardiac function and morbidity and mortality after cardiac operations.

Methods: Eighty patients undergoing coronary artery bypass grafting with a preoperative left ventricular ejection fraction (LVEF) less than 30% scheduled for elective coronary bypass grafting agreed to participate in this prospective, randomized trial. The triiodothyronine (T(3)) (Group I) and control groups (Group II) were equally divided. Patients randomized to the T(3) group received T(3) 125 microg/day orally for 7 days preoperatively and from the first postoperative day till the discharge. Outcome variables included perioperative hemodynamic data, inotropic requirements, morbidity and mortality. Hemodynamic data were collected before induction of anesthesia and following every 4 h. The thyroid profile was determined upon admission, after the induction of anesthesia, 5 min after the start of cardiopulmonary bypass (CPB) and after hourly intervals and after 24th hour, at 24h intervals till the 120th hour.

Results: There were 6 deaths, three in each group. Patients in the T(3) group demonstrated a higher cardiac index than patients in the placebo group in the entire post-CPB periods (P<0.01). Mean inotropic requirements remained lower in the T(3) group than in the placebo group (P<0.001).

Conclusions: Although our study stresses the benefits of oral T(3) administration on the hemodynamic and prognostic parameters in patients with impaired left ventricular function and undergoing CABG weakly, it may warrant further much larger scaled studies that can reach statistical significance.