The Relationship between Intraoperative Respiratory Variability of the Inferior Vena Cava Diameter on Transesophageal Echocardiography and Acute Kidney Injury in Patients Undergoing Coronary Artery Bypass Grafting Surgery: A Prospective Multicenter Cohort Study

BACKGROUND: Currently, there have been no studies on the relationship between the transesophageal echocardiography (TEE), an indicator of respiratory variability of the inferior vena cava diameter (ΔIVC), and the incidence of postoperative acute kidney injury (AKI) in patients undergoing coronary artery bypass grafting (CABG) surgery have been conducted. The primary objective of this study was to investigate the relationship between ΔIVC and the incidence of postoperative AKI in CABG patients. METHODS: A multicenter prospective cohort study was conducted from September 2021 to July 2022 in patients over 18 years of age who underwent elective CABG. We measured the diameter of the inferior vena cava (D-IVC) via M-mode TEE using the transgastric long axis (LAX) view (70°) of the IVC, approximately 2 cm caudal to the right atrium. All echocardiographic indicators were measured three times in a row at the following three time points: T0 (before the CABG surgery began), T2 (approximately 5-10 minutes after protamine neutralization), and T3 (after the sternum was closed), after which the values were averaged. RESULTS: The association between the TEE index (ΔIVC) and the incidence of postoperative AKI in patients with CABG was not statistically significant. However, multivariate logistic regression analysis revealed that the central venous pressure (CVP) at T3 was independently associated with postoperative AKI. CONCLUSIONS: The TEE indicator ΔIVC was not significantly associated with the incidence of postoperative AKI. The clinical efficacy of TEE in isolated coronary artery bypass surgery needs further study.