The effects of thyroid hormones levels on prognosis after pediatric heart surgery

Abstract

In this study, we aimed to evaluate the effects of thyroid hormone levels on the prognosis of patients who underwent congenital heart surgery under cardiopulmonary bypass. A total of 40 children who underwent congenital heart surgery were enrolled to this prospective study. The patients were divided into two groups according to the presence or absence of postoperative low cardiac output state. Plasma free thyroxine, free triiodothyronine and thyroid stimulating hormone levels were measured preoperatively and at 24 and 48 hours postoperatively. Postoperative low cardiac output state was observed in five patients (12.5 %). Preoperative free thyroxine levels were significantly higher in the low cardiac output state group (p=0.021). Postoperative free triiodothyronine and free thyroxine levels were significantly lower, and lactate levels, inotropic index were significantly higher in the low cardiac output state group. Duration of mechanical ventilation, intensive care unit stay, operation and cardiopulmonary bypass were significantly higher in the low cardiac output state group. Four patients (10 %) died in the early postoperative period, and all of them were in the low cardiac output state group. Our findings showed that the occurrence of low cardiac output state after congenital heart surgery was associated with the high levels of preoperative free thyroxine and the reduction in percentage of free triiodothyronine and free thyroxine levels at the 24th and 48th hours postoperatively.