A systematic review and meta-analysis of GLASS staging system in the endovascular treatment of chronic limb-threatening ischemia.

OBJECTIVE: The objective of this study was to evaluate the application of the Global Anatomic Staging System (GLASS) in the endovascular treatment of chronic limb-threatening ischemia (CLTI). METHODS: We performed systematic research between June 2019 and February 2022, including articles investigating the relationship of GLASS classification with the outcomes of endovascular interventions in the treatment of CLTI. Data from the included studies were pooled and meta-analyzed. The primary endpoints were limb-based patency (LBP) at 1-year follow-up and immediate technical failure (ITF). Secondary endpoints included major amputation. We performed subgroup analysis between studies that reported on calcium modifier inclusion during GLASS classification and studies that did not. RESULTS: Eleven studies, including 1816 patients (1975 limbs) met the inclusion criteria. The pooled ITF rates for GLASS stages I, II, and III are 5.52% (95% confidence interval [CI], 3.74%-8.07%), 7.39% (95% CI, 5.32%-10.18%), and 21.07% (95% CI, 13.48%-31.39%) respectively. The pooled LBP for GLASS stages I, II, and III are 68.43% (95% CI, 53.44%-80.37%), 41.52% (95% CI, 18.91%-68.37%), and 38.64% (95% CI, 19.83%-61.57%). The relative risk (RR) for ITF regarding composite GLASS I and II stages vs GLASS III is 3.96 (95% CI, 1.96-7.98). The RR for LBP of GLASS I and II versus GLASS stage III is 1.51 (95% CI, 0.86-2.64). Pooled major amputation rates for the composite GLASS I, II and GLASS III stages are 7.62% (95% CI, 5.44%-10.58%) and 15.43% (95% CI, 11.72%-20.05%) respectively, whereas the RR between GLASS I, II, and GLASS III stages is 1.84 (95% CI, 1.18-2.87). CONCLUSIONS: Our study demonstrated that patients with CLTI undergoing endovascular interventions classified as GLASS stage III had almost a four-fold risk increase for ITF and 1.84 times the risk of major amputation compared with stages I and II. Additionally, GLASS classification correctly predicted ITF for all three stages, whereas it failed to predict stage I and II LBP outcomes. Safe conclusions regarding LBP cannot be drawn due to the low quality and small number of the included studies, necessitating further research. Furthermore, we displayed the importance of calcium moderator inclusion in the accurate classification of GLASS.