Effect of Subclinical Hyperthyroidsm on the Outcome of Coronary Artery Graft Bypass Surgery

Introduction: Subclinical hyperthyroidsm is associated with negative effects on cardiovascular system. We aimed to evaluate the association between pre-operative thyroid hormones and post-operative outcome in patients undergoing coronary artery by-pass graft (CABG) surgery. Methods: A hundred and eighty nine patients with isolated CABG surgery were included into the study. Patient’s clinical characteristics, surgical details and post-operative mortality and morbidities were recorded.Patients were divided into two groups according to their TSH level with cut-off point of 0,35 was assumed. Results: The first group consists of 16 patients (9%) with subclinical hyperthyroid (SH) and the second group includes 173 euthyroid patients. In post-operative period; the incidence of arrhythmia, renal failure and inotropy requirement were significantly higher in SH group (p<.0001, p: 0.0002 and p<.0001 respectively) The incidence of peri-operative mortality was similar between groups. (p: 0.0860). Lenght of stay in intesive care unit and overall were significantly higher in patients with SH (p: 0.0102 and p: 0.0004 respectively). Discussion and Conclusion: Pre-operative subclinical hyperthyroidsm didn’t effect peri-operative mortality but may lead to higher postoperative complications such as arrhythmia, renal failure and low cardiacoutput syndrome in patients undergoing CABG surgery.