Lower extremity arteriosclerosis obliterans(LEASO)is a disease characterized by the formation of atherosclerotic plaques in the lower extremity arteries,leading to arterial stenosis,occlusion,and consequent chronic limb ischemia.This article analyzes the clinical data of a patient with LEASO complicated by an iodine contrast agent allergy,along with the treatment involving intravascular ultrasound(IVUS)-guided endovascular intervention performed without contrast agent,and reviews relevant literature.The patient,a 53-year-old female,presented with coldness and numbness in the left lower extremity and pain after walking for 2 years,symptoms which had worsened over the past 2 months,with a maximum claudication distance of less than 50 meters.The lower extremity arterial CT angiography(CTA)results indicated"left iliac artery occlusion and left superficial femoral artery stenosis."After examination,the patient exhibited allergic symptoms.Upon admission,other diseases were ruled out.Given that the lower extremity symptoms severely impacted the patient's daily life and considering the potential for contrast agent allergy,the use of contrast agent was abandoned.IVUS guidance alone was employed to assess the intravascular condition for the interventional procedure.The surgical interventions chosen were drug-coated balloon angioplasty of the left superficial femoral artery and stent implantation in the left iliac artery.Postoperatively,the patient was able to walk normally,the discomfort resolved,and the treatment outcome was satisfactory.For LEASO patients with contrast agent allergy or other contraindications to contrast use,the sole use of IVUS guidance combined with invasive blood pressure monitoring to intraoperatively assess efficacy can effectively avoid contrast agent administration,providing a valuable reference for clinicians managing such cases.