an Observational Study Evaluting the Effectiveness and Safety of DKutting LL Noval Scoring Balloon Angioplasty for Vessel Preparation Facilitated by IVUS on the Lower Limb Ischemia Patients With Calcified Lesions

Inclusion Criteria: * Age ≥ 18 years and ≤ 85 years. * Clinical diagnosis of lower extremity atherosclerotic arterial disease, with a Rutherford Classification of Category 2-5. * The patient has provided written informed consent. * Life expectancy \> 1 year. * Confirmed by clinical and CTA examination: de novo or restenotic lesions after PTA in the femoropopliteal or infrapopliteal arteries, with no stent implantation within 2 cm of the target lesion. Stenosis ≥70% or chronic total occlusion (CTO). * Lesion confirmed by CTA and color Doppler to have moderate to severe calcification (PACSS Grade 3-4). Lesion can be single or tandem, with a total length ≤150 mm. Reference vessel diameter near the target lesion ≥2 mm. * Allowable location of the target lesion: ≥1 cm distal to the common femoral artery bifurcation, and up to 10 cm above the ankle. * If the lesion is below-the-knee (BTK), the inflow vessels must have no non-target lesions, or any non-target lesions must be successfully treated with the current device without vascular complications. * No serious vascular complications such as flow-limiting dissection occur after pre-dilation of the target lesion. * Presence of at least one reconstructible infrapopliteal runoff vessel patent to the ankle. Exclusion Criteria: * Allergy to contrast media. * Coagulopathy; severe hepatic insufficiency (ALT or AST \> 3 times the upper limit of normal). * Cardiac insufficiency (New York Heart Association Class III-IV). * Life expectanc…