Changes of Thyroid Function and Hemodynamic State in Patients Undergoing Coronary Artery Bypass Grafting / 日本心臓血管外科学会雑誌

ABSTRACT

Perioperative changes in thyroid function and hemodynamic state were studied in 6 hypothyroid patients and 15 euthyroid patients who underwent coronary artery bypass grafting. Serum free T₃ and total T₃ concentrations declined significantly in hypothyroid patients after the surgery. Serum total T₃ concentration decreased significantly also in euthyroid patients, indicating the occurrence of“euthyroid sick syndrome”in this group. Hypothyroid patients resulted in significantly lower left ventricular stroke work index despite greater central venous pressure and pulmonary capillary wedge pressure, and greater requirements of dopamine and dobutamine compared with those in euthyroid patients. The results indicated poorer postoperative cardiac performance in hypothyroid patients. Serum free T₃ concentration after cardiopulmonary bypass demonstrated a significant positive correlation with left ventricular stroke work index measured simultaneously. Preoperative serum free T₃ concentration showed a significant negative correlation with the postoperative dopamine and dobutamine requirements. Therefore, the results suggest that free T₃ has inotropic effects and the concentration of this hormone can be a predictor for a incidence of postoperative low cardiac output. In conclusion, since hypothyroid patients undergoing coronary artery bypass grafting are prone to have low cardiac output status, careful perioperative management, including hormone replacement therapy, is required for the patients.