Background: Chronic limb-threatening ischemia (CLTI) affects millions of people and causes health care burden around the globe. Global Limb Anatomic Staging System (GLASS) was proposed as a new anatomic system for integrating the complexity of threatened limb.
Methods: We retrospectively classified computed tomography angiography images of threatened limbs into GLASS stages between January 2018 and April 2020. Comorbidities, limb treatments, and outcomes including amputation-free survival (AFS), reintervention and mortality were compared and the likelihood of benefit from revascularization was estimated according to GLASS. Kaplan-Meier estimate was used to determine the rates of endpoint events at 1 year. Multivariate analysis was performed to identify predictors of those outcomes.
Results: In our study, 285 threatened limbs in 263 patients were stratified including GLASS stage I disease (N.=53, 19%), stage II (N.=129; 45%) and stage III (N.=103; 36%) disease. The percentage of limbs undergoing endovascular revascularization and minor amputation increased significantly with increasing GLASS stage. On Kaplan-Meier analysis, increasing GLASS stage was associated with 1-year reduced AFS (stage I: 96.1%, stage II: 94.1%, stage III: 83.9%; log rank P=0.016). The percentage of 1-year reintervention rate in infrapopliteal GLASS grade 3-4 (15%) was significantly higher than the percentage of reintervention in infrapopliteal GLASS grade 0-2 (5%) (Log rank P=0.002). Infrapopliteal GLASS grade 3 and 4 was the independent predictor of reduced AFS.
Conclusions: GLASS stage correlated with intensity of limb treatment and with clinical outcomes at 1 year. Infrapopliteal GLASS grade 3 and 4 independently predicted the reduced amputation-free survival.