Thyroid hormone treatment hastens recovery after cardiac surgery

Thyroid hormone treatment after surgery requiring heart bypass speeds recovery in children undergoing correction of congenital heart defects, according to a clinical trial published in The Lancet.

The effects were greatest in the patients who underwent long and difficult surgeries. Following trauma or surgery or during a critical illness, thyroid hormone concentrations plummet. Many experts thought this was an adaptive response by the body to minimize metabolic demands during a time of crisis and that the best response was to do nothing. But there was never any proof of this, and researchers have suggested in recent years that transient hypothyroidism can be dangerous in some cases. Children and adults with highly depressed thyroid function fare worse following cardiac surgery than patients with mildly lowered thyroid function.

The Heidelberg group conducted a randomized, double-blind, placebo-controlled trial of 40 children, ages 2 days to 10.4 years, who were scheduled for surgery to repair congenital heart defects. Patients were treated intravenously with either saline solution or tri-iodothyronine each day after surgery until dopamine treatment was stopped or after 12 days, whichever came first. The treated children had an increase in cardiac index by than 20% (p<0.004) in the first 24 hours after the operation when compared to placebo-treated kids.

The results were especially dramatic in patients who had undergone operations that lasted four or more hours.

The results suggest that low levels of thyroid hormone may be potentially harmful for patients who have serious cardiac dysfunction, and this form of treatment may be useful.