1. Chronic limb ischemia (CLI) is defined as limb pain that occurs “at rest or impending limb loss that is caused by severe compromise of blood flow to the affected extremity.”¹ In CLI, a cascade of pathophysiologic events results from a chronic lack of blood supply over several weeks to months, ultimately leading to rest pain and/or trophic lesions in the legs.¹⁸ Rutherford and Fontaine’s classification criteria place CLI at the end of the spectrum of chronic peripheral arterial disease (Table 11.1).

2. Classic symptoms and clinical manifestations of CLI include the following: lower extremity rest pain, nonhealing ulcers, tissue loss, gangrene, pallor of the foot, and rubor dependency.¹ CLI places patients at a significant risk for amputation and cardiovascular events, thereby making it the most important clinical indication for below-the-knee revascularization.¹⁶ Risk factors of CLI are the same as that of general atherosclerosis and include cigarette smoking, diabetes mellitus (DM), dyslipidemia, hypertension, obesity, metabolic syndrome, hyperhomocysteinemia, increased fibrinogen, and high levels of C-reactive protein. The diagnosis of CLI is made based on clinical manifestations and objective data including the following hemodynamic parameters: ankle-brachial index of 0.4 or less, ankle systolic pressure of 50 mm Hg or less, toe systolic pressure of 30 mm Hg or less,¹ and transcutaneous oxygen less than 20 mm Hg.¹² The goal of revascularization in CLI, whether surgical or endovascular, is to provide in-line blood flow to the foot through at least 1 patent artery, in an effort to preserve a functional limb, while decreasing ischemic pain, minimizing tissue loss, facilitating wound healing,⁹ improving patient function and quality of life, and prolonging survival.¹⁸

3. The gold standard for revascularization for CLI has long included open surgical revascularization, endartectomy, and surgical infrainguinal bypass.¹