ABSTRACT
Objective To compare the influences of off-pump and on-pump coronary artery bypass grafting operation on plasma thyroid hormones.Methods Forty patients undergoing coronary surgery were randomly divided into off-pump group(n=20)and on- pump group(n=20).Plasma thyroid hormones(T_3,T_4,FT_3,FT_4,rT_3)and thyroid-stimulating hormone(TSH)were studied perio- peratively.Results Before operation,the values of aU the variables were within normal range in the two groups.In off-pump group, T_3 and FT_3 concentration dropped significantly after operation,reaching the lowest value at first day postoperatively[T_3:(39.7?6.2) ng/dl vs.(78.6?2.1)ng/dl,P0.05),which were within normal range all along,rT_3 concentration rose significantly after operation,reaching the highest value at third day postoperatively[(82.1?26.8)ng/dl vs.(42.3?15.6)ng/dl, P0.05),whereas baseline,operative and postoperative variables were similar.Con- clusion Off-pump operation has some influences on plasma thyroid hormones,showing"low T_3 syndrome"postoperatively,that is similar to what on-pump operation does.