The Global Limb Anatomic Staging System Predicts Clinical Outcomes in Chronic Limb Threatening Ischemia

Abstract

The global limb anatomic staging system (GLASS) has recently been proposed to facilitate clinical decision-making in revascularization options for chronic limb-threatening ischemia (CLTI). The purpose of the present study was to define its relationship to treatment outcomes in CLTI. Consecutive angiograms performed at a single institution for CLTI from April 2017 to July 2019 were retrospectively reviewed. Subjects with significant aortoiliac disease, previous infrainguinal stents, or functioning bypass grafts were excluded. The GLASS score was assigned from the preintervention angiograms, and the treating surgeon determined the infrapopliteal target artery pathway for the limb at risk. Demographic data, procedural details, and clinical outcomes were analyzed. The cohort consisted of 167 patients and 194 limbs, of which 175 of 194 (90%) had presented with tissue loss and 149 of 182 (83%) with WIfI (wound, ischemia and foot infection) stage 3 or 4 disease. The GLASS stage was GLASS for 14%, GLASS 2 for 18%, and GLASS 3 for 68%. GLASS 3 anatomy was present in 85% of the 52 limbs treated by bypass and 55% of the 108 limbs that underwent endovascular interventions (P < .001). Revascularization was not performed in 34 limbs, most of which were GLASS 3 (85%). GLASS 3 was associated with a higher rate of endovascular intervention immediate technical failure (ie, failure to reestablish the target artery pathway) than were GLASS 1 and 2 (30% vs 2%; P < .001). After a median follow-up of 10 months, limb-based patency after endovascular intervention was significantly lower for GLASS 3 than for GLASS 1 and 2 limbs (n = 108; P = .018; Fig 1). GLASS 3 was associated with reduced major adverse limb event-free survival in both the endovascular intervention group and the overall revascularized cohort (n = 160; P = .001; Fig 2). GLASS 3 was also associated with decreased survival, amputation-free survival, and reintervention and amputation-free survival (Table). In a Cox proportional hazards model, GLASS 3 (hazard ratio, 2.35; 95% confidence interval, 1.30-4.24; P = .005) and the wound component of the WIfI scale (hazard ratio, 2.64; 95% confidence interval, 1.26-5.53; P = .010) were independent predictors of major adverse limb event-free survival events after revascularization. Preprocedure angiographic GLASS stage 3 is an independent and significant predictor of major adverse clinical outcomes in patients with CLTI.TableLog-rank comparison of clinical outcomes in patients with CLTI undergoing revascularizationEventOverall (n = 160)Endovascular intervention (n = 108)GLASS 1-2 (n = 57)GLASS 3 (n = 103)P valueGLASS 1-2 (n = 49)GLASS 3 (n = 59)P valueMortality7 (12)30 (29).0147 (17)19 (32).03Major amputation6 (11)18 (17).185 (10)11 (19).18Amputation-free survival12 (21)44 (43).00411 (22)28 (47).007Major adverse limb events9 (16)28 (27).0557 (14)16 (27).061MALE-FS15 (26)53 (51).00113 (27)32 (54).002Reintervention amputation-free survival22 (39)62 (60).00819 (39)39 (66).011Limb-based patencyNANANA20 (41)34 (58).018MALE-FS, Major adverse limb event-free survival; NA, not applicable.Data presented as number (%). Open table in a new tab Fig 2Cumulative major adverse limb event-free survival using Kaplan-Meir method with log-rank test (n = 160).View Large Image Figure ViewerDownload Hi-res image Download (PPT)