GLASS (Global Limb Anatomic Staging System): a critical appraisal

Abstract

Background: THE Global Vascular Guidelines (GVGs) propose a new Global Anatomic Staging System (GLASS) resulting in three stages of complexity for intervention. The aim of this study was to retrospectively classify a large cohort of CLTI patients according to the GLASS, evaluating its distribution in a real-world setting.

Methods: Retrospective, single center, observational study enrolling all consecutive CLTI patients submitted to infra-inguinal endovascular revascularization in our institution, between June 2014 and September 2019. Patients were categorized according to the GLASS for femoro-popliteal (FP), infra-popliteal (IP) and infra-malleolar grading. FP and IP grades were merged to get the final GLASS stage for each limb.

Results: The study included 1995 CLTI patients who underwent 2850 endovascular procedures in which 6009 arterial lesions were successfully treated. The FP segment was classified as: 1292 (45.3%) grade 0, 475 (16.6%) grade 1, 159 (5.6%) grade 2, 209 (7.4%) grade 3, and 715 (25.1%) grade 4. The IP segment was classified as: 1529 (53.6%) grade 0, 183 (6.4%) grade 1, 80 (2.8%) grade 2, 207 (7.3%) grade 3, and 851 (29.9%) grade 4. The combination of FP and IP grading led to GLASS stages: 922 (32.3%) stage 1, 375 (13.2%) stage 2, 1472 (51.6%) stage 3.

Conclusions: The distribution of the FP, IP and final GLASS grading was mainly grouped at the two extremes, letting the intermediate grades rather scarce. The majority of patients present with an absent or severely diseased pedal arch, stressing the need to incorporate infra-malleolar disease into the GLASS.