The Global Anatomic Staging System Does Not Predict Limb Based Patency of Tibial Endovascular Interventions.

Abstract Objective: Anatomic grading systems have historically been poor predictors of patency after endovascular tibial interventions. The Global Vascular Guidelines proposed a new Global Anatomic Staging System (GLASS) to estimate one-year limb-based patency (LBP). The purpose of this study was to determine the association of GLASS with LBP following endovascular tibial interventions. Methods: We included all patients presenting to our multidisciplinary diabetic limb preservation service between 01/2012 and 8/2020 who underwent first-time endovascular tibial revascularization for chronic limb-threatening ischemia. Diagnostic angiograms were reviewed to define the preferred target artery pathway and assign a GLASS stage to each treated limb. One-year LBP was calculated and compared across GLASS stages using Kaplan-Meier curves with log-rank tests and Cox proportional hazards models. Results: We performed tibial revascularization in 96 limbs (5.2% rest pain, 56.3% ulcer, 37.5% gangrene), including isolated tibial interventions in 61.5% and tibial+femoropopliteal interventions in 38.5%. 15.6% of limbs were GLASS stage 1, 28.1% were GLASS stage 2, and 56.3% were GLASS stage 3. Overall one-year LBP was 43.2±6.3%, and did not differ significantly across GLASS stages (P=.42). The hazard ratio for failed LBP was 1.94 (95% CI 0.70-5.41) for GLASS stage 2 and 1.49 (95% CI 0.56-3.94) for GLASS stage 3 limbs (versus GLASS stage 1). When analyzed excluding the calcium modifier, LBP remained similar across GLASS stages (P=0.72). Major amputation was uncommon, occurring in 9.3±3.4% of limbs at one year, and did not significantly differ by GLASS stage (P=0.98). Conclusion: The Global Anatomic Staging System did not predict limb-based patency following tibial endovascular interventions. Given the low major amputation rates in this cohort, anatomic complexity should not preclude endovascular limb salvage efforts below the knee.