Endovascular treatment of below-the-knee chronic total occlusions

With the aging of the US population as well as the epidemic of obesity, metabolic syndrome, and diabetes, it is expected that lower extremity peripheral arterial disease (PAD) and specifically critical limb ischemia (CLI) will continue to be a major healthcare challenge. Although a full discussion of the epidemiology and pathophysiology of CLI is beyond the scope of this chapter, a few points will help provide perspective for the reader. An important concept to convey is that the relationship between diabetes and CLI is not casual, but rather causal in nature. The associations between diabetic prevalence, complications, and mortality track closely with the rates of CLI and of nontraumatic amputations. Over the course of a lifetime, a diabetic patient is significantly more likely to undergo limb loss than a nondiabetic-with over 60% of nontraumatic amputations being performed in diabetic individuals. Although the pathophysiology leading to CLI in these patients is multifactorial-neuropathy, deformity, impaired immune response, and inflammation-the role of diffuse below-the-knee (BTK) atherosclerosis remains central to the failure of healing of foot ulcers. Traditionally, diabetic foot ulcers were classified as neuropathic or ischemic in nature. We now know that 50% of “neuropathic” ulcers may have impaired healing due to underlying ischemia. This ischemia is often microvascular, but in many cases due to distal BTK disease involving the plantar circulation.