Clinical Outcomes of Additional Below-The-Ankle Intervention Compared to Below-The-Knee Intervention Alone: A Post-Hoc Analysis of a Prospective Multicenter Study

Purpose: To investigate the clinical implication of additional below-the-ankle (BTA) intervention in patients with chronic limb-threatening ischemia (CLTI) undergoing below-the-knee (BTK) intervention. Materials and Methods: A sub-analysis was performed using data from the LIBERTY trial (ClinicalTrials.gov identifier NCT01855412), a prospective, observational, core-laboratory adjudicated, multicenter study of endovascular intervention in 1204 patients. Patients with CLTI (Rutherford Classification 4-6) who underwent BTK intervention were included in this sub-analysis. Participants were then stratified into 2 treatment groups according to whether at least one lesion intervened on was BTA (n=66) or not (n=273). The decision on whether and where to intervene was made during the procedure. The main outcome measures included major amputation, target vessel revascularization (TVR), major adverse events (MAE), survival, amputation-free survival, major adverse limb events or peri-operative death (MALE-POD), and all-cause death. Other outcome measures included procedural success, procedural complications, and wound healing rate. Results: There were no differences in procedural success or severe angiographic complications between the 2 groups. At 1-year post-procedure, patients in the BTK group had a higher rate of freedom from major amputation (95.0% vs. 86.9%, respectively; HR: 2.87, 95% CI: 1.17-7.03), a higher rate of freedom from TVR (80.1% vs. 66.9%, respectively; HR: 1.94, 95% CI: 1.14-3.32), a higher rate of freedom from MALE-POD (94.6% vs. 86.9%, respectively; HR: 2.65, 95% CI: 1.10-6.41), and a higher rate of freedom from MAE at both 1 (76.0% vs. 60.1%, respectively; HR: 2.00, 95% CI: 1.24-3.22) and 3 years post procedure (67.5% vs. 55.8%, respectively; HR: 1.69, 95% CI: 1.08-2.65). There was a significantly lower rate of survival in the BTK group at 3 years (74.3% vs. 91.1%, respectively; HR: 0.35, 95% CI: 0.14-0.87). After risk adjustment, there was a higher rate of all-cause death in the BTK group at 3 years (19.4% vs. 9.1%, respectively; p=0.023) post-intervention. Conclusion: Patients with disease requiring intervention to BTA lesions have a potential increased amputation rate in the short term, but BTA intervention carries a potential survival benefit in the long term when compared to BTK intervention alone.