Influence of subclinical hypothyroidism on early outcome of patients undergoing CABG surgery

Abstract

Background: Subclinical hypothyroidism is associated with elevated TSH with normal T3 and T4 levels. Its effect on cardiac surgery  outcome is controversial. Some authors revealed adverse outcome in form of arrythmia and congestive heart failure. This study aimed to  investigate the effect of subclinical hypothyroidism on early outcome of patients undergoing coronary artery bypass graft (CABG)  surgery.

Methods: This study included 27 patients with subclinical hypothyroidism subjected to elective CABG surgery (Group A) and  group B that contained 27 patients with normal thyroid function. Both groups were followed up for one month postoperative regarding  operative mortality and postoperative outcomes.

Results: Cases required prolonged mechanical ventilation and postoperative inotropic  support were significantly higher among the SCH group compared to the euthyroid group (p=0.024, 0.018 respectively). The occurrence of  postoperative AF and the respiratory complications was significantly higher in SCH group in comparison to the euthyroid group  (p=0.039, 0.022 respectively). Mortality was recorded in only one case of SCH group and in 2 cases of the euthyroid group (p=0.998).  

Conclusion: SCH is associated with increased postoperative AF, need for inotropic support and prolonged mechanical ventilation. Preoperative assessment of thyroid functions is recommended to be performed routinely before surgery.