The effect of cardiac catheterization on thyroid functions in infants with congenital heart diseases: A prospective observational study

Abstract

<title>Abstract</title> Background This study aims to determine the incidence, clinical course and risk factors of hypothyroidism following cardiac catheter (CC) in infants with congenital heart diseases (CHD). Subjects and Methods: This prospective study involved 115 patients with CHD, all aged 3 years or younger, who underwent CC, as well as 100 healthy age- and sex-matched controls. Baseline thyroid function tests (TFTs) were conducted for both the patients and controls. In the CHD cohort, TFTs were reassessed 3 weeks after the CC, and for those with abnormal TFT values at this time, the tests were repeated 1week later. Levothyroxine was started in patients with persistent thyroid hypofunction at 3- and 4-weeks assessment following CC. Results Four weeks after CC, 12% of the studied group exhibited hypothyroidism. Univariate analysis identified significant predictors of hypothyroidism following CC: aortic stenosis (RR = 10.0 (1.49–66.99), <italic>P</italic> = 0.018), duration of fluoroscopy during CC (RR = 2.12 (0.99–4.26), <italic>P</italic> = 0.05), and total iodinated contrast media (iCM) during CC (RR = 2.5 (1.35–3.55), <italic>P</italic> = 0.019). Multivariate analysis indicated that iCM dose was the sole significant predictor of developing hypothyroidism (RR = 2.10 (1.01–3.23), <italic>P</italic> = 0.04). ROC curve analysis showed that the cut-off point of iCM dose for prediction of hypothyroidism evolution is 8.7 gm/kg (26.1 ml/kg), (sensitivity: 83%, specificity: 65%), while the cut-off point of fluoroscopy duration which predicts development of hypothyroidism is 24 minutes, (sensitivity: 83%, specificity: 66%). Conclusion Higher doses of iCM and longer duration of fluoroscope during CC are risk factors for evolution of hypothyroidism post-CC. We recommend assessing thyroid profile 4 weeks after CC, particularly in patients who received an iCM dose greater than 8.7 gm/kg and/or exposed to fluoroscopy for more than 24 minutes.