JENALI scoring system divides each tibial vessel (anterior tibial artery, posterior tibial artery, and peroneal artery) into proximal, mid-, and distal segments [1]. The segment is considered patent and assigned a score of 1 if contrast is visualized within the vessel. If the segment is occluded, it is assigned a score of 0. The segment will be considered patent, so long as there is constant contrast line regardless if it fills through direct antegrade flow or indirect retrograde flow. A maximum score of 9 signifies that all the tibial vessels are patent, and a minimum score of 0 signifies that none of the segment is angiographically patent. The strength of the scoring system lies in its simplicity [1].

In 1987, Dr. Taylor, the anatomist and plastic surgeon, introduced the angiosome concept, separating the body into distinct three-dimensional blocks of tissue fed by source arteries [2]. Angiosomes of the foot are defined by different branches of the three main arteries (Fig. 3.1) [3, 4]. The anterior tibial artery supplies the anterior ankle which turns into the dorsalis pedis and subsequently supplies the dorsum of the foot. The posterior tibial artery supplies the heel through the calcaneal artery, instep through the medial plantar artery, while the lateral plantar artery supplies the lateral midfoot and forefoot. The peroneal artery breaks off into two segments which are the anterior perforating branch which supplies lateral anterior portion of the ankle and calcaneal branch which supplies the plantar portion of the heel .

The foundations for TASC were laid in 2000 in an attempt to discuss how to treat arterial disease [5]. In an attempt to discuss key aspects of diagnosis and management, update the research, and provide more emphasis on management for the population with diabetes, the TASC group reconvened and updated the guideline in 2007 (TASC II system) [6]. TASC II system has graphically presented and thus is more easily and uniformly applied. Classifications of aortoiliac lesions and femoral-popliteal lesions are summarized in Figs. 3.2 and 3.3, respectively.

Endovascular therapy is the treatment of choice for type A lesions, and surgery is the treatment of choice for type D lesions. Endovascular treatment is the preferred treatment for type B lesions, and surgery is the preferred treatment for good-risk type C lesions. The patient’s comorbidities, the fully informed patient preference, and the local operators’ long-term success rates must be considered when making treatment recommendations for TASC B and C lesions .

Rutherford and Fontaine classifications are based on symptom severity from perfusion. However, perfusion is only one determinant of outcome. Wound extent and the presence and severity of infection also greatly impact the threat to a limb. Therefore, a new classification was implemented by the Society for Vascular Surgery Lower Extremity Guidelines Committee [9]. The estimated risk of amputation of each stage is summarized in Fig. 3.4.