Oral Triiodothyronine Supplementation Decreases Low Cardiac Output Syndrome After Pediatric Cardiac Surgery

Triiodothyronine Supplementation in Infants Undergoing Cardiopulmonary Bypass: A Randomized Controlled Trial

Cardiopulmonary bypass (CPB) profoundly suppresses circulating thyroid hormone levels in infants. We performed a multicenter randomized placebo controlled trial to determine if triiodothyronine (T3) supplementation improves reduces time to extubation (TTE) in infants after CPB. Infants (n = 220) undergoing cardiac surgery with CPB and stratified into 2 age cohorts: ≤30 days and >30 days to <152 days were randomization to receive either intravenous triiodothyronine or placebo bolus followed by study drug infusion until extubated or at 48 hours, whichever preceded. T3 did not significantly alter the primary endpoint, TTE (hazard ratio for chance of extubation (1.08, 95% CI: 0.82-1.43, P = 0.575) in the entire randomized population with censoring at 21 days. T3 showed no significant effect on TTE (HR 0.82, 95% CI:0.55-1.23, P = 0.341) in the younger subgroup or in the older (HR 1.38, 95% CI:0.95-2.2, P = 0.095). T3 also did not significantly impact TTE during the first 48 hours while T3 levels were maintained (HR 1.371, 95% CI:0.942-1.95, P = 0.099) No significant differences occurred for arrhythmias or other sentinel adverse events in the entire cohort or in the subgroups. This trial showed no significant benefit on TTE in the entire cohort. T3 supplementation appears safe as it did not cause an increase in adverse events. The study implementation and analysis were complicated by marked variability in surgical risk, although risk categories were balanced between treatment groups.

Indonesian Study: Triiodothyronine for Infants Less than 5 Months Undergoing Cardiopulmonary Bypass

This study evaluates the efficacy and safety of oral triiodothyronine on time to extubation for infants less than 5 months undergoing heart surgery in Indonesia, and primarily relates to patients in emerging programs with high malnutrition and mortality. In this randomized, double-blind, placebo-controlled trial, oral triiodothyronine (T3, Tetronine®) 1 μg/kg-body weight/dose or placebo (saccharum lactis) was administered via nasogastric tube every 6 h for 60 h to treatment group. A total of 120 patients were randomized into T3 (61 patients) and placebo (59 patients) groups. The majority of the patients had moderate to severe malnutrition (55.83%) with a high post-operative mortality rate of 23.3%. The T3 group showed significantly higher serum FT3 levels from 1 until 48 h post cross-clamp removal (p < 0.0001), lower incidence of low cardiac output syndrome at both 6 h (28 [45.9%] vs. 39 [66.1%] patients, p = 0.03, OR 2.3, 95% CI: 1.10-4.81) and 12 h after cross-clamp removal (25 [41.7%] vs. 36 [63.2%], p = 0.02, OR 2.40, 95% CI: 1.14-5.05). Although not statistically significant, the treatment group had shorter median (IQR) intubation time (2.59 [1.25-5.24] vs. 3.77 [1.28-6.64] days, p = 0.16, HR 1.36, 95% CI: 0.88-2.09)] and lower mortality (10 [16.4%] vs. 18 [30.5%], p = 0.07]. Patients with Aristotle score < 10.0 (low risk) receiving T3 had faster extubation than placebo patients (p = 0.021, HR of 1.90, 95% CI: 1.10-3.28) and were significantly less likely to require CPR or experience infection (p = 0.027, OR 8.56, 95% CI:0.99-73.9 and p = 0.022, OR 4.09 95% CI: 1.16-14.4, respectively). Oral T3 supplementation reduced overall incidence of low cardiac output syndrome and significantly reduced the time to extubation in low-risk patients. Therefore, prophylactic oral T3 administration may be beneficial in these patients.Trial Registration: ClinicalTrials.gov NCT02222532.

Decreased triiodothyronine (T3) as a predictor for prolonged mechanical ventilation in critically ill patients with cardiac surgery

BACKGROUND

This study aimed to examine the correlation between thyroid hormone and prolonged mechanical ventilation (MV) in adult critically ill patients having undergone cardiac surgery.

METHODS

The present study refers to a retrospective, cohort study conducted at Nanjing First Hospital from March 2019 to December 2020. Patients receiving cardiac surgery and admitting to the Cardiovascular Intensive Care Unit (CVICU) in the study period were screened for potential inclusion. Demographic information, thyroid hormone and other laboratory measurements and outcome variables were recorded for analysis. Prolonged MV was defined as the duration of MV after cardiac surgery longer than 5 days. Thyroid hormones were assessed for the prognostic significance for prolonged MV.

RESULTS

One thousand eight hundred ninety-six patients who underwent cardiac surgery were screened for potential enrollment. Overall, 118 patients were included and analyzed in this study. Patients fell to the control (n = 64) and the prolonged MV group (n = 54) by complying with the duration of MV after cardiac surgery. The median value of total triiodothyronine (TT3) and free triiodothyronine (FT3) were 1.03 nmol/L and 3.52 pmol/L in the prolonged MV group before cardiac surgery, significantly lower than 1.23 nmol/L (P = 0.005) and 3.87 pmol/L, respectively in control (P = 0.038). Multivariate logistic regression analysis indicated that TT3 before surgery (pre-op TT3) had an excellent prognostic significance for prolonged MV (OR: 0.049, P = 0.012).

CONCLUSIONS

This study concluded that decreased triiodothyronine (T3) could be common in cardiac patients with prolonged MV, and it would be further reduced after patients undergo cardiac surgery. Besides, decreased T3 before surgery could act as an effective predictor for prolonged MV after cardiac surgery.

Predictors of Low Cardiac Output Syndrome in Infants After Open-Heart Surgery

OBJECTIVE

To evaluate the predictors of low cardiac output syndrome (LCOS) in infants with congenital heart disease (CHD) after cardiopulmonary bypass (CPB).

STUDY DESIGN

A total of 217 infants were enrolled and classified according to whether they developed LCOS after cardiac surgery. Each infant's preoperative and intraoperative clinical variables were collected.

RESULTS

The incidence of LCOS was 28.11% in our study. The univariate analysis showed that the LCOS group was younger than the non-LCOS group (25.69 ± 25.01 days vs. 44.45 ± 26.97 days, P < 0.001), with a higher proportion of neonates (60.7 vs. 27.6%, P < 0.001) and a higher proportion of patients with a RACHS-1 score ≥4 (50.8 vs. 17.9%, P < 0.001). A lower weight (3.70 ± 0.74 vs. 4.23 ± 1.10 kg, P = 0.001), longer ACC time (61.96 ± 21.44 min vs. 41.06 ± 18.37 min, P < 0.001) and longer CPB time (131.54 ± 67.21 min vs. 95.78 ± 62.67 min, P < 0.001) were found in the LCOS group. The levels of free triiodothyronine (FT3) (4.55 ± 1.29 pmol/L vs. 5.18 ± 1.42 pmol/L, P = 0.003) and total triiodothyronine (TT3) (1.80 ± 0.56 nmol/L vs. 1.98 ± 0.54 nmol/L, P = 0.026) were also lower in the LCOS group. The multivariate binary logistic regression analysis and receiver operating characteristic (ROC) indicated that the ACC time, FT3 level and body weight were independent predictors of LCOS.

CONCLUSIONS

In our patient population, we first propose that preoperative FT3 can predict the occurrence of postoperative LCOS. ACC time, FT3 level and body weight are independent predictors of LCOS and maybe helpful in reducing the incidence of postoperative LCOS in the future.

Thiamine levels in Indonesian children with congenital heart diseases undergoing surgery using cardiopulmonary bypass machine

BACKGROUND

This study evaluated thiamine levels in Indonesian children with congenital heart diseases before and after cardiopulmonary bypass and their relationship with clinical and surgical outcomes.

METHOD

A prospective, single center cross-sectional study was conducted to evaluate thiamine levels in 25 children undergoing congenital heart diseases surgery with cardiopulmonary bypass procedure. Thiamine levels were quantified using a high-performance liquid chromatography method.

RESULT

Preoperative thiamine deficiency was observed in one subject. Thiamine levels did not differ statistically between nutritional status and clinical outcomes categories. There were no significant changes in thiamine levels before and after cardiopulmonary bypass (median pre versus post (P_25-75): 50 ng/mL (59.00-116.00) and 83.00 ng/mL (70.00-101.00), p = 0.84), although a significant reduction in thiamine levels were observed with longer cardiopulmonary bypass duration (p = 0.017, R = -0.472).

CONCLUSION

Thiamine levels were not significantly impacted by cardiac surgery except in patients undergoing extremely long cardiopulmonary bypass duration. However, clinical outcome was not affected by thiamine levels.

A prospective randomized clinical study of perioperative oral thyroid hormone treatment for children undergoing surgery for congenital heart diseases

Context :

Thyroid hormone deficiency is known to occur after cardiac surgery and known as nonthyroid illness (NTI). The beneficial role of perioperative thyroid hormone supplementation in children has been debatable more so with oral supplementation.

Aims :

The aim is to evaluate the role of pre-operative oral thyroid hormone therapy in preventing NTI. To assess its effect on post-operative thyroid hormone levels, hemodynamic parameters, and cardiac function of infants and small children undergoing pediatric cardiac surgery.

Settings and Design :

Prospective randomized, double-blinded controlled trial at a tertiary level pediatric cardiothoracic center.

Materials and Methods :

Sixty-five children aged under 18 months undergoing corrective surgeries on cardiopulmonary bypass were included. Patients were randomized into two equal groups: placebo group (given placebo) and thyroxine group (given thyroxine tablet 10 μg/kg) orally once a day starting on the preoperative evening till the fifth postoperative day. The postoperative hemodynamics, inotropic requirement, ventilatory requirement, and cardiac function on echocardiography were observed.

Statistical Tests :

Shapiro–Wilk test, Mann–Whitney/t-test, Chi-square test, ANOVA with Tukey correction were used.

Results:

Serum triiodothyronine and thyroxine levels postoperatively were significantly higher in the thyroxine group than in the placebo group. There was no significant difference in left ventricular ejection fraction, hemodynamic variables, extubation time, and length of intensive care unit (ICU) stay between the two groups.

Conclusions:

In infants and small children undergoing corrective cardiac surgery, perioperative oral thyroid hormone therapy reduces the severity of postoperative NTI. It increases the serum level of thyroid hormones but the therapy does not translate to better hemodynamics, reduced inotropic requirement, reduced ventilatory requirement, improved myocardial function or reduced ICU stay when compared to placebo.

The effect of oral triiodothyronine supplementation on lactate and pyruvate after paediatric cardiac surgery

OBJECTIVE

To determine if triiodothyronine alters lactate, glucose, and pyruvate metabolism, and if serum pyruvate concentration could serve as a predictor of low cardiac output syndrome in children after cardiopulmonary bypass procedures.

METHODS

This study was ancillary to the Oral Triiodothyronine for Infants and Children undergoing Cardiopulmonary bypass (OTICC) trial. Serum pyruvate was measured in the first 48 patients and lactate and glucose were measured in all 208 patients enrolled in the OTICC study on the induction of anaesthesia, 1 and 24 hours post-aortic cross-clamp removal. Patients were also defined as having low cardiac output syndrome according to the OTICC trial protocol.

RESULT

Amongst the designated patient population for pyruvate analysis, 22 received placebo, and 26 received triiodothyronine (T3). Lactate concentrations were nearly 20 times greater than pyruvate. Lactate and pyruvate levels were not significantly different between T3 and placebo group. Glucose levels were significantly higher in the placebo group mainly at 24-hour post-cross-clamp removal. Additionally, lactate and glucose levels peaked at 1-hour post-cross-clamp removal in low cardiac output syndrome and non-low cardiac output syndrome patients, but subsequently decreased at a slower rate in low cardiac output syndrome. Lactate and pyruvate concentrations correlated with glucose only prior to surgery.

CONCLUSION

Thyroid supplementation does not alter systemic lactate/pyruvate metabolism after cardiopulmonary bypass and reperfusion. Pyruvate levels are not useful for predicting low cardiac output syndrome. Increased blood glucose may be regarded as a response to hypermetabolic stress, seen mostly in patients with low cardiac output syndrome.

Preoperative thyroid hormone levels predict ICU mortality after cardiopulmonary bypass in congenital heart disease patients younger than 3 months old

BACKGROUND

We aimed to study the effectiveness of preoperative thyroid hormone levels in predicting intensive care unit (ICU) mortality after cardiopulmonary bypass (CPB) in infants with congenital heart disease (CHD).

METHODS

We retrospectively reviewed and analyzed data from 133 patients younger than 3 months old who underwent cardiac surgery with CPB from June 2017 to November 2019. ICU mortality prediction was assessed by multivariate binary logistic regression analysis and area under the curve (AUC) analysis.

RESULTS

Non-survivors were younger (17.46 ± 17.10 days vs. 38.63 ± 26.87 days, P = 0.006), with a higher proportion of neonates (9/13 vs. 41/120, P = 0.017) and a higher proportion of individuals with a Risk Adjustment for Congenital Heart Surgery-1 (RACHS-1) score ≥ 4 (8/13 vs. 31/120, P = 0.020). No significant difference was found in CPB and aortic cross-clamping (ACC) time. The levels of free triiodothyronine (FT3) (3.91 ± 0.99 pmol/L vs. 5.11 ± 1.55 pmol/L, P = 0.007) and total triiodothyronine (TT3) (1.55 ± 0.35 nmol/L vs. 1.90 ± 0.57 nmol/L, P = 0.032) were higher in survivors than in non-survivors. In the ICU mortality prediction assessment, FT3 was an independent mortality predictor and showed a high AUC (0.856 ± 0.040).

CONCLUSIONS

The preoperative FT3 level was a powerful and independent predictor of ICU mortality after CPB in infants with CHD younger than 3 months old.

Frequency of thyroid dysfunction in pediatric patients with congenital heart disease exposed to iodinated contrast media - a long-term observational study

Background The thyroid gland of patients with congenital heart disease may be exposed to large doses of iodine from various sources. We assessed the thyroid response after iodine exposure during conventional angiography in cardiac catheterization and angiographic computer tomography in childhood. Methods Retrospective mid- to long-term follow-up of 104 individuals (24% neonates, 51% infants, 25% children) with a median age and body weight of 104 days [0-8 years] and 5.3 kg [1.6-20]. Serum levels of thyroid-stimulating hormone, free triiodthyronine and free thyroxine were evaluated at baseline and after excess iodine. We also assessed risk factors that may affect thyroid dysfunction. Results Baseline thyroidal levels were within normal range in all patients. The mean cumulative iodinate contrast load was 6.6 ± 1.6 mL/kg. In fact, 75% had experienced more than one event involving iodine exposure, whose median frequency was three times per patient [1-12]. During the median three years follow-up period [0.5-10], the incidence of thyroid dysfunction was 15.4% (n=16). Those patients developed acquired hypothyroidism (transient n=14, long-lasting n=2 [both died]) with 10 of them requiring temporary replacement therapy for transient thyroid dysfunction, while four patients recovered spontaneously. 88 individuals (84.6%) remained euthyroid. Repeated cardiac interventions, use of drugs that interfere with the thyroid and treatment in the intensive care unit at the index date were strong predictors for acquired thyroid dysfunction. Conclusions The incidence of acquired hypothyroidism after iodine excess was 15.4%. However, most patients developed only transient hypothyroidism. Systemic iodine exposure seems to be clinically and metabolically well tolerated during long-term follow-up.