Contemporary Results of Intra-Arterial Thrombolysis for Acute and Acute-On-Chronic Lower Limb Ischemia

Background: To evaluate the immediate and long-term outcomes of catheter-directed thrombolysis (CDT) in infrainguinal arterial occlusions presenting with acute limb ischemia (ALI) or acute-on-chronic limb ischemia (ACLI), and to assess its safety and durability across different clinical and anatomical settings. Methods: We retrospectively analyzed 128 consecutive patients who underwent initial CDT for infrainguinal occlusions between January 2014 and December 2024. Patients were divided into ALI (n = 85) and ACLI (n = 43). CDT was performed with urokinase infusion via multihole catheters. Technical success, complications, and adjunctive procedures were recorded. Long-term outcomes were assessed using Kaplan-Meier analysis, with primary end points including patency, limb salvage, amputation-free survival (AFS), and freedom from reintervention. Results: CDT was effective or partially effective in 109 patients (85.1%), with similar success rates in ALI and ACLI. At 30 days, major amputation and mortality rates were 4.6% and 3.1%, respectively. Three major bleeding events required thrombolysis discontinuation. The median follow-up was 36 months (range 1-120), with a follow-up index of 0.72. At 5 years, estimated survival was 74.2%. Limb salvage was 79% in ALI and 86% in ACLI (P = 0.5), and AFS was 58.5% versus 74% (P = 0.1). Primary and secondary patency at 5 years were 22% and 26% for ALI, and 32.5% and 48% for ACLI (P = 0.7 and P = 0.2). Freedom from reintervention was 36% for ALI and 43% for ACLI (P = 0.4). Chronic kidney disease was the only independent predictor of death or amputation (hazard ratio: 2.9; 95% confidence interval: 1.2-6.8). Conclusion: CDT is a safe and effective revascularization strategy for infrainguinal occlusions in both ALI and ACLI. Outcomes were not significantly influenced by clinical presentation or lesion anatomy, while comorbidities-particularly chronic kidney disease-were strongly associated with poor prognosis. Despite limited long-term patency, CDT remains a valuable option in selected patients, especially when combined with adjunctive endovascular or surgical approaches.