ABSTRACT
Transient myocardial ischemia that occurs during cardiac surgery leads to oxidative stress and production of free radicals. Selenium [Se] status has important implications for cardiovascular morbidity and mortality as selenium is an integral component of the enzymes glutathione peroxidase and 5-iodothyronine deiodinase. Thyroid hormones have important effect on the heart and peripheral vascular system. Cardiopulmonary bypass [CPB] results in low triiodothyronine [T3] state, due to central depression of the hypothalamic pituitary axis together with impaired conversion of T4 to T3 secondary to reduced activity of iodothyronine deiodinase. This work aimed to study the effect of cardiopulmonary bypass on selenium and thyroid hormone status in infants and children with congenital heart disease [CHD]. Also it aimed to study the possible effect of selenium and thyroid hormone status on the hemodynamic condition of these infants and children after open heart surgery. Twenty five children were subjected to open heart surgery in the Cardio Thoracic Unit, Pediatric Hospital, Cairo University. The patients were subjected to full history taking, general and local cardiac examination, M mode, 2D and Doppler Echocardiography. Serum samples were collected, at the induction of anesthesia and 48 h after cardiopulmonary bypass for assessment of selenium, free T3[FT3]and free T4[FT4] levels. Assessment of serum selenium takes place at [NRC] using graphite furnace atomic absorption spectrometry [GFAAS]. Assessment of FT3 and FT4 takes place at Radioactive Isotope Department using RIA technique. Significantly lower postoperative selenium, FT3 and FT4 serum levels, compared to those at the induction of anesthesia, were found [p< 0.005, 0.025, and 0.025 respectively]. Longer CPB time was associated with lower FT3 and FT4 levels [r =0.49 and 0.63 respectively]. On the other hand higher FT3 and FT4 levels were associated with less time needed for inotropic support [r =0.48 and 0.60 respectively]. There is significant decrease of selenium, free T3 and freeT4 levels after cardiopulmonary bypass. The degree of decrease of thyroid hormones is affected by CPB time. Thyroid hormone levels have an evident impact on the myocardial functions and hemodynamic condition after open heart surgery