Triglyceride-glucose index for predicting the post-procedural wound healing of Rutherford grade 5 ischemia: a retrospective study

Triglyceride-glucose (TyG) index has come to be a new insulin resistance (IR) marker and has also been independently linked with peripheral artery disease (PAD). Rutherford Grade 5 ischemia is characterized by localized tissue loss or active ulceration, with critically compromised perfusion, a high propensity for infection, and a narrow healing window-making it the most refractory and precarious tipping point in limb-salvage therapy, where progression to amputation is most likely. The present study attempted to evaluate the clinic utility of the TyG index in predicting the post-procedural wound healing of Rutherford grade 5 ischemia. This analysis incorporated 98 cases of chronic limb-threatening ischemia (CLTI) classified as Rutherford grade 5, treated via endovascular approaches from January 2016 to December 2022. This study applied univariate logistic regression to discern independent predictors, alongside computing receiver operating characteristic (ROC) curves to evaluate prognostic accuracy for wound recovery after interventions in these individuals. For deeper analysis of contributing elements, the cohort was split retrospectively and randomly into training (n = 68, 70%) and validation (n = 30, 30%) groups. Leveraging training set information, both univariate and multivariate logistic regressions enabled the formulation of a nomogram to forecast healing post-revascularization in Rutherford grade 5 ischemia. Assessment of the model's effectiveness involved ROC evaluations, calibration assessments, and decision curve analysis (DCA). The results showed that the TyG index was statistically significant in Rutherford grade 5 patients (p = 0.011). Univariate analysis indicated that the TyG index was an independent risk factor (OR: 3.96, 95% CI: 1.33-11.73, p = 0.013), and it's area under the ROC curve (AUC) for predicting delayed wound healing was 0.68, with a best cutoff value of 8.83, sensitivity of 67.1%, and specificity of 71.4%. In the training cohort, the TyG index, triglyceride (TG), and smoking status were identified as independent predictors of wound healing after endovascular treatment in Rutherford grade 5 patients (all p < 0.05). A nomogram was constructed using these three variables, demonstrating an AUC of 0.83 (95% CI: 0.71-0.95) in the training set and 0.68 (95% CI: 0.45-0.91) in the validation set, with good calibration observed in both cohorts. DCA indicated that this model could provide additional net clinical benefit in the low cost-effectiveness ratio threshold range. The TyG index may be an independent risk factor for delayed wound healing in Rutherford grade 5 patients following endovascular therapy. The nomogram model incorporating TyG index, TG levels, and smoking status demonstrates good predictive performance for wound healing after revascularization in these patients, and may positively impact early diagnosis/treatment, prevention of overtreatment, and precision medicine with optimized resource allocation.Trial registration the registration number PJKSKY2024423 the date of registration 15th July 2024.