Evaluation of Preoperative Left Ventricular Relative Wall Thickness for Predicting Postoperative Acute Kidney Injury in Elderly Hip Fracture Patients

<b>Objectives:</b> This study aimed to explore the association between left ventricular relative wall thickness (RWT) and postoperative acute kidney injury (AKI) in elderly patients who underwent hip fracture surgery. Additionally, we evaluated the prognostic value of RWT for postoperative clinical outcomes in this high-risk group. <b>Methods:</b> This prospective study included 131 patients aged ≥ 65 years who underwent surgery for femoral neck or intertrochanteric hip fractures. Preoperative echocardiographic parameters, including RWT, were recorded and their associations with postoperative AKI were analyzed. Postoperative cardiovascular complications and clinical outcomes were assessed. <b>Results:</b> Postoperative AKI occurred in 19.1% of patients and was significantly associated with higher in-hospital mortality (20% vs. 5.6%; <i>p</i> = 0.036). Patients who developed AKI had significantly higher RWT (0.54, 0.503, <i>p</i> = 0.048, respectively). Receiver operating characteristic (ROC) curve analysis was performed for preoperative echocardiographic parameters, such as interventricular septum (IVS), posterior wall thickness (PWT), left atrium (LA) diameter, and RWT, to evaluate their predictive ability for AKI. The area under the curve (AUC) values were 0.645 for IVS, 0.632 for PWT, 0.713 for LA diameter, and 0.628 for RWT (all <i>p</i> < 0.05). Although LA diameter had the highest AUC, RWT showed the highest sensitivity (96%) at the cut-off value of 0.435. Subgroup analyses comparing patients with RWT < 0.435 and ≥0.435 showed no significant differences in AKI, mortality, delirium, intensive care unit admission rates, cardiac complications, or ischemic events (all <i>p</i> > 0.05). <b>Conclusions:</b> Preoperative RWT demonstrated a modest but statistically significant association with postoperative AKI in elderly hip fracture patients with preserved left ventricular ejection fraction. Although its standalone predictive value is limited, RWT may contribute to perioperative risk stratification when interpreted alongside other echocardiographic, clinical, and biochemical parameters in this vulnerable high-risk patient population.