Regional tissue oxygen saturation as an indicator of wound healing during endovascular treatment for chronic limb-threatening ischaemia

Objective: It is important to evaluate limb blood flow during the perioperative period to salvage affected limbs in patients with chronic limb-threatening ischaemia (CLTI). However, it is difficult to evaluate limb blood flow during endovascular treatment (EVT). This study aimed to investigate the usefulness of regional tissue oxygen saturation (rSO 2 ) values measured by near-infrared spectroscopy (NIRS) techniques during EVT to predict the wound healing prognosis in patients with CLTI. Method: Patients with CLTI who successfully underwent EVT between April 2018 and March 2022 were included. Patients who had infections or failed EVT were excluded. The rSO 2 value was measured in the affected limb using the NIRS device (TOE-20, Astem Co., Ltd., Japan) during EVT. At one year after EVT, the patients were divided into two groups: healing and non-healing. Intraprocedural rSO 2 values were retrospectively analysed to determine the cut-off value for wound healing using receiver operating characteristic (ROC) curve analysis. Results: A total of 34 patients (healing group: 15; non-healing group: 19) were included in this study. Intraprocedural rSO 2 values were significantly higher in the healing group than in the non-healing group (51.1±3.4% versus 44.4±5.0%, respectively; p<0.001). ROC curve analysis revealed that the optimal cut-off intraprocedural rSO 2 value for wound healing within one year was 47.0% (sensitivity: 86.7%, specificity: 73.7%). Conclusion: The results of this study showed that intraprocedural rSO 2 values during EVT may be useful in the prediction of postoperative wound healing in patients with CLTI.