Influence of a Novel Morphology-Driven Classification on Limb Salvage after Isolated Tibial Intervention for Chronic Limb Threatening Ischemia

Abstract

Infra-popliteal interventions for chronic limb-threatening ischemia (CLTI) can be impacted by the morphology of the tibial vessels. The aim of this study was to examine the impact of a novel morphology-driven classification on the outcomes of isolated tibial intervention for CLTI. A database of patients undergoing isolated tibial interventions for CLTI at a single center between 2010 and 2020 was retrospectively queried. Patients with isolated Infra-popliteal disease were identified, and their anatomy was scored as present or absent for lesion calcification (1 point), target vessel diameter<3.0 mm (1 point), lesion length>300mm (1 point) and poor pedal runoff score (1 point). Patients were then divided into three groups: low-risk (0 or 1 points), moderate-risk (2 points), and high-risk (3 or 4 points). Intention to treat analysis by the patient was performed. Limb-based patency (the absence of reintervention, occlusion, critical stenosis (>70%), or hemodynamic compromise with ongoing symptoms of CLTI as it related to the patency of the preoperatively determined target artery pathway) was assessed. Patient-orientated outcomes of amputation-free survival (AFS; survival without major amputation) and freedom from major adverse limb events (MALE; Above ankle amputation of the index limb or major re-intervention (new bypass graft, jump/interposition graft revision) were evaluated. 1607 patients (55% male, average age 60 years, 3846 vessels) underwent tibial intervention for CLTI. The majority of the patients were diabetic and of Hispanic. origin Morphologically, 27%, 31%, and 42% of the vessels were categorized as low risk, moderate risk, and high risk, respectively. There was a significant worsening of the infra-popliteal Global Limb Anatomic Staging System (GLASS) grading as the morphological risk increased. The 30-day major adverse cardiac events (MACE) were equivalent across the groups and were under the stated objective performance goal (OPG) of ≤10%. In contrast, both the 30-day MALE and the 30-day Major Amputations were significantly different across the groups, with the low-risk group remaining under the OPG of ≤9% and ≤4%, respectively, while the moderate-risk and high-risk exceeded the goal threshold. For the OPG. Freedom from MALE was 60±5%, 46±5%, and 22±9% at 5 years for low-, moderate-, and high-risk groups, respectively (mean ± SEM; p =0.008. Overall amputation-free survival (AFS) was 55±5%, 37±6%, and 18±7% at 5 years for low-, moderate-, and high-risk groups, respectively (mean ± SEM; p=0.003). Tibial anatomic morphology impacts isolated tibial endovascular intervention with adverse morphology associated with poorer short and long-term outcomes. Risk stratification based on anatomic predictors should be an additional consideration as one intervenes on infra-popliteal vessels for CLTI.