ESPE Abstracts

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 included 102 patients with CHD, aged ≤ 3 years who underwent CC. Thyroid function tests were evaluated before CC, one day, one week, two weeks and four weeks after the procedure.

Results: 12% of the studied group showed hypothyroidism four weeks after CC. Univariate analysis revealed that the significant predictors of hypothyroidism following CC are aortic stenosis (RR=10.0 (1.49-66.99), P=0.018), duration of fluoroscopy (RR=1.12 (0.99-1.26), P=0.05), and total cumulative dose of iodinated contrast media (iCM) (RR=1.01 (1.003 -1.01), P=0.019). Multivariate analysis revealed that iCM dose was the only significant predictor of developing hypothyroidism (RR=1.00 (1.00-1.01), P=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: 83.3%, specificity: 65.1%), while the cut-off point of fluoroscopy duration which predicts development of hypothyroidism is 24 minutes, (sensitivity: 83.3%, specificity: 65.9%). Acquired hypothyroidism after CC persists in 5% of this cohort for a median duration of 20 months.

Conclusion: Exposure to higher dose of iCM and longer duration of fluoroscope during CC are risk factors for evolution of thyroid hypofunction. We recommend assessment of thyroid profile 4 weeks after CC particularly in patients who received a dose of iCM higher than 8.7 gm/kg and/or exposed to fluoroscopy for more than 24 min.