Nomogram for predicting amputation-free survival in acute lower limb ischemia patients treated by endovascular therapy

Objectives: To develop a novel and accurate nomogram to predict survival without amputation in patients with acute lower limb ischemia (ALLI) during the first year following endovascular therapy. Methods: Patients with ALLI who underwent endovascular therapy in our department between January 2012 and September 2020 were screened and included in the research. The included patients were randomly divided into a training and validation cohorts, respectively. Univariate and multivariate analyses were used in the training cohort to identify independent risk factors for amputation-free survival (AFS). A nomogram was then developed according to the identified independent risk factors. The nomogram was then validated in the validation cohort. Results: 415 Chinese patients with 417 affected limbs were included in this study. Among these patients, 311 patients were classified into the training cohort and 104 patients were assigned to the validation cohort. Most patients were men (n = 240) and the average age of patients was 71.43 (standard deviation 8.86) years old. After the univariate and multivariate analyses, advanced age (p < 0.001), history of smoking (p < 0.001), atrial fibrillation (p < 0.001), and insufficient outflow (p = 0.001) were revealed as independent risk factors for AFS during the first year. The nomogram yielded AUROC values of 0.912 (95 % confidence interval [CI]: 0.873-0.950) and 0.889 (95 % CI: 0.812-0.967) in the training and validation cohorts, respectively. Conclusion: Advanced age, history of smoking, atrial fibrillation, and insufficient outflow were independent negative predictors for AFS in ALLI patients treated by endovascular therapy. The novel nomogram offered an accurate prediction of AFS in ALLI patients.