1-year outcomes of mechanical aspiration thrombectomy using IndigoTM aspiration system in patients with acute limb ischemia in Japan: the INSIGHT-ALI Study

Background Acute limb ischemia (ALI) is a vascular emergency associated with high rates of amputation and mortality. Mechanical aspiration thrombectomy using the IndigoTM Aspiration System enables effective treatment with a low bleeding risk, and its clinical use for ALI has been widely applied in clinical settings. However, comprehensive evaluations incorporating detailed angiographic data remain limited. Purpose This study aimed to evaluate the clinical outcome of mechanical aspiration thrombectomy using IndigoTM System in real-world ALI patients. Methods This multicenter, retrospective, observational single-arm study was conducted across 18 Japanese institutions between January and December 2024. A total of 179 limbs in 173 patients (mean age: 77.2 ± 9.9 years, male: 59%, history of peripheral artery disease: 51%, Rutherford I: 17%, Rutherford IIa: 41%, and Rutherford IIb: 42%) with ALI who were treated with the IndigoTM System without adjunctive thrombolytics. The outcome measures were technical success, defined as Thrombo-aspiration In Peripheral Ischemia (TIPI) grade 2 or 3 at completion angiography and amputation-free survival (AFS). Angiographic data were analyzed at a core laboratory, and prognostic factors were evaluated using multivariable analysis. Results Technical success was achieved in 93% (160/179 limbs). Presence of infrapopliteal lesions (odds ratio, 8.54; 95% confidence interval [CI], 1.08-67.2; P=0.042) was significantly associated with technical failure. The 1-year AFS rate was 70.1 ± 3.5%. 1-year AFS was significantly associated with non-ambulatory status (hazard ratio [HR], 3.21; 95%CI, 1.76-5.85; P <0.001), hemodialysis (HR, 2.39; 95%CI, 1.25-4.58; P=0.008), Rutherford classification IIb at presentation (HR, 1.91; 95%CI, 1.08-3.38; P=0.027), and technical failure (HR, 2.46; 95%CI, 1.02-5.96; P=0.046). Risk stratification analysis demonstrated that 1-year AFS was 86.9 ± 4.6% in patient without risk factors, while zero survival rate was found in patients with three or more risk factors. Conclusions The current study revealed that mechanical aspiration thrombectomy using the IndigoTM System enables effective revascularization with high technical success and favorable 1-year clinical outcomes in patients with ALI. Non-ambulatory status, hemodialysis, Rutherford IIb classification, and technical failure were significantly associated with AFS. Risk stratification based on these factors allows prognostic prediction and may support clinical decision-making in ALI management.