Clinical Trial: Can Oral T3 Normalize Thyroid Hormone Levels Following Cardiopulmonary Bypass in Children?

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Oral Triiodothyronine Normalizes T3 Levels After Surgery For Pediatric Congenital Heart Disease

Brief Summary: Low triiodothyronine (T3) syndrome defines as decrease of T3 levels during critically ill. This decrease of T3 levels was observed after congenital heart surgery using cardiopulmonary bypass. Previous largest study,Triiodothyronine for Infants and Children Undergoing Cardiopulmonary bypass (TRICC) study showed T3 supplementation decreased time to extubation for infants less than 5 months undergoing cardiopulmonary bypass. Intravenous regiment was known effective in maintaining T3 levels during pediatric cardiac surgery. This drug preparation however is not commonly used in many countries due to the relatively high costs and/or the simple lack of availability. The use of oral T3 to treat postoperative low T3 levels in pediatric patients has not been reported so far, although recent adult studies showed benefit in using oral T3 after cardiac surgery. The purpose of this study was to determine if oral T3 supplementation could prevent the decline of serum T3 in children less than 2 years of age undergoing congenital heart surgery using CPB.

Detailed Summary:

The Research Ethics Board at the National Cardiovascular Center Harapan Kita approved this study and written, informed consent was obtained from the parents or legal guardians before randomization. Randomization by block permutation was performed to determine treatment group assignment. Randomization occured on the day before surgery by a nurse investigator. A pharmacist who was not involved in the study prepared the study medication. Investigators and participants were blinded to the assigned group until after the end of the study.

Thyroid hormonal levels were analyzed by standard 3rd generation thyrotropic-stimulating hormone (TSH), serum free T4 (FT4), free T3 (FT3), and total T3 (TT3) Micro particle Enzyme Immunoassays (Abbott Laboratories, Abbott Park, USA). The serum total T4 (TT4) assay used a Fluorescence Polarization Immunoassay (Abbott Laboratories, Abbott Park, USA). Hormone levels were measured on induction of anesthesia, before the study drug was given (T0) and at 1, 6, 18, 36 and 72 hours after removal of the aortic-cross-clamp.

Baseline clinical data collected included age, gender, birth weight, type of operation, and Aristotle score. Diagnosis and operative procedures were classified as high or low risk with an Aristotle score cut off of ≥ 9 as high risk. As modifying factors, we measured duration of surgery, cardiopulmonary bypass (CPB) time, cross-clamp time, ultrafiltration during CPB and degree of hypothermia during CPB, and the use of amiodarone. Non-pulsatile perfusion technique was used during CPB. Steroid (methyl prednisolone 35-50 mg/kg) was given before CPB. We used povidone-iodine for skin disinfection in all subjects. Although this study was not powered to detect clinical differences between the treatment groups, clinical outcome parameters were measured as a potential guide to subsequent
Sponsor: National Cardiovascular Center Harapan Kita Hospital Indonesia

Current Primary Outcome: Free T3 (FT3) Levels [ Time Frame: during the first 36 hours after cross clamp removal ]

Free T3 levels were measured up to 36 hours after cross-clamp removal


Original Primary Outcome: Total T3 (TT3) and free T3 (FT3) levels during the first 72 hours after cross clamp removal. [ Time Frame: up to 72 hours after cross clamp removal ]

Additional hormonal outcomes were thyroxine (TT4) levels, free T4 (FT4) levels and thyroid stimulating hormone (TSH) levels


Current Secondary Outcome: Number of Patients With Possible Side Effects of Thyroid Hormone Supplementation Particularly Suggesting Hyperthyroid Symptoms. [ Time Frame: Since the first dose of oral T3 until 7 days after surgery ]

Specific symptoms of hyperthyroidism included cardiac dysrhythmia requiring medical or electrical treatment, hypertension (mean systolic or diastolic blood pressure more than 2 standard deviation above normal for age) and hyperthermia (>37.5 degree Celsius). One patient in low dose group had hypertension directly after surgery due to unrecognized coarctation of the aorta and this patient was withdrawal from the protocol.


Original Secondary Outcome: Possible side effects of thyroid hormone supplementation particularly suggesting hyperthyroid symptoms within 7 days after surgery. [ Time Frame: Since the first dose of oral T3 until 7 days after surgery ]

Specific symptoms of hyperthyroidism included cardiac dysrhythmia requiring medical or electrical treatment, hypertension (mean systolic or diastolic blood pressure more than 2 standard deviation above normal for age) and hyperthermia (>37.5 degree Celsius).


Information By: National Cardiovascular Center Harapan Kita Hospital Indonesia

Dates:
Date Received: January 28, 2013
Date Started: April 2010
Date Completion:
Last Updated: February 2, 2013
Last Verified: February 2013