Coronary bypass surgery in patients on thyroxin replacement therapy.

The outcome of coronary bypass surgery was analyzed in 25 patients who were on thyroxin replacement therapy for chronic thyroid disorders at the time of operation. It was hypothesized that if such patients were given only their routine dose of thyroxin on the day of surgery, hemodynamic and cardiorespiratory recovery may be poor. All the patients on thyroxin replacement therapy were given their routine dose of thyroxin orally or via a nasogastric tube in the perioperative period. No supplemental dose was used. Based on preoperative levels of thyroid stimulating hormone, 68% of these patients were biochemically hypothyroid prior to surgery. Analysis of a large number of variables showed no difference in outcome against a control group who had no previous thyroid problems. We conclude that routine thyroxin administration is all that is required for a satisfactory outcome in patients undergoing coronary bypass surgery while on thyroxin replacement therapy.