Critical limb threatening ischemia "CLTI 'is not a separate local disease but also it is a part of generalized vascular disorder. A clinical syndrome that can be presented by many symptoms and signs as rest pain, gangrene and chronic ulceration more than 2 weeks (1).

The Global Vascular guidelines 'GVG "proposes a new Global Anatomic Staging System (GLASS), GLASS incorporates two novel and important concepts, the target arterial path (TAP) and estimated limb-based patency (LBP). Based on appropriate angiographic imaging, the TAP is defined by the treating surgeon or internationalist as the optimal arterial pathway to restore in-line (pulsatile) flow to the ankle and foot. LBP allows more direct comparison of anatomic outcomes across revascularization strategies in CLTI. The complexity of disease traversed by the TAP is integrated in the GLASS. Femoropopliteal (FP) and infrapopliteal (IP) arterial segments are individually graded on a scale of 0 to 4.(2)(3) Using a consensus based matrix, these segmental grades are combined into three overall GLASS (I-III) stages for the limb, reflecting the complexity of the disease with a proposed likelihood of immediate technical failure ' ITF " and 1 year "LBP " after endovascular intervention of " TAP ' (1)

Inclusion Criteria:

• Patients with infrainguinal CLTI

Exclusion Criteria:

• Patients with concomitant Aorto-iliac lesions
• Acute ischemia patients
• Post Traumatic ischemia

Patients attending the Vascular Surgery Clinics in Assiut University Hospitals with infra inguinal CLTI will be recruited to participate in the study. Based on high quality angiography, patients presented with CLTI will be assigned into 3 stages according to GLASS