Do preoperative low triiodothyronine levels affect early kidney injury after coronary artery bypass grafting? A retrospective study

Sedat Ozcan, Gündüz Yümün

Abstract

Objective: Acute kidney injury is a common complication of cardiac surgery, and factors such as advanced age, diabetes mellitus, and low left ventricular function are reported to be risk factors for the development of acute kidney injury after coronary artery bypass grafting (CABG). There are few studies in the literature reporting the relationship between preoperative low T3 syndrome and cardiac surgery-related acute kidney injury. In this study, 1 aimed to evaluate the effect of preoperative free T3 levels on early postoperative kidney injury based on glomerular filtration rate and acute kidney injury development in isolated elective on-pump coronary artery bypass grafting patients.
Methods: The study was conducted in our hospital on patients who underwent isolated elective on-pump CABG surgery. Patients who underwent other open-heart surgery other than CABG, patients who had previously undergone open-heart surgery, patients who underwent off-pump CABG, patients with known preoperative renal failure, patients with known thyroid disease, and patients for whom the study data were not available were excluded. Finally, a total of 183 patients included in this study were examined and compared in two groups according to their preoperative fT3 levels.
Results: The mean preoperative fT3 value was 2.06 ± 0.74 in Group 1 and 2.93 ± 0.53 in Group 2 (p = 0,000). The preoperative glomerular filtration rate value was 86.36 ± 11.16 and 88.78 15.79 in Group 1 and Group 2, respectively (p = 0.150). Preoperative Hgb, diabetes mellitus, and age data were similar in both groups (p=0.487, p=0.936, and p=0.073, respectively). The mean glomerular filtration rate change ratio (postoperative/preoperative glomerular filtration rate) was 0.93 ± 0.13 and 1.05 ± 0.56 (p = 0.437) for Groups 1 and 2, respectively.
Conclusion: As a conclusion, according to the results of this study, no association was found between preoperative low fT3 and the development of postoperative acute kidney injury in on-pump coronary artery bypass grafting patients. However, we believe that further prospective studies with larger patient numbers would be beneficial to investigate the relationship between specific thyroid hormone disorders and the development of acute kidney injury after coronary artery bypass grafting.