Given the high co-prevalence of PAD and CKD, it is important to understand how treatment decisions for one condition may affect the other. Patients with CKD already face exceedingly high mortality, and kidney disease may be worsened by limb-saving interventions. For those who have advanced CKD but are not yet dialysis dependent, revascularization either percutaneously or surgically may lead to ESRD. Physicians and patients often face this dilemma of what is more life changing for the patient—permanent dialysis or a limb amputation and prosthesis. Indeed, either outcome is suboptimal, but the risk-benefit ratio must be discussed explicitly prior to proceeding or withholding therapy for CLI.

Even in CKD patients with CLI, selecting the subpopulation that will benefit from lower limb revascularization is challenging. Complications from CLI are among the major causes of mortality in dialysis patients and survival is reduced after major amputation [21]. Several factors contribute to these poor outcomes. First, early detection of PAD may be missed due to lack of symptoms. ESRD patients may be physically inactive and therefore not have a history of classic claudication. If known at an early stage, therapies could be implemented to prevent progression of PAD to CLI. Second, the use of the ABI to diagnose PAD in CKD and ESRD has also been questioned due to the high prevalence of vascular calcification which may result in false negative tests. Finally, CKD persons have a high burden of associated cardiovascular morbidities resulting in a high threshold for the treatment of anything less than severely disabling CLI.

Patients with CLI who at baseline are non-ambulatory and have a short life expectancy can be considered for primary amputation or endovascular revascularization. Ambulatory patients with a life expectancy >2 years and those who are good surgical candidates should undergo bypass [33]. Actual treatment algorithms show considerable practice variations. Some centers advocate primary amputation in patients with ESRD citing dismal outcomes with revascularization and limb sparing procedures [22], while some have recommended avoiding surgeries altogether, on the basis of data pointing toward poor outcomes with both surgical bypass and amputation [23]. Yet others have supported early endovascular and surgical revascularization in the ESRD population [24, 25]. Clearly, there is a lack of consensus among practitioners and this highlights the need for including CKD patients in large trials of CLI therapy .

The endovascular approach is typically chosen due to its rapidity, minimal invasiveness, and lack of complications associated with surgical wound healing. Unfortunately, patients who are generally considered unsuitable for surgery are also often poor candidates for endovascular procedures, because of the high incidence of outflow lesions and because of accelerated vascular calcifications. Recent technical and device advances have also resulted in centers performing infrapopliteal/outflow lesion angioplasties in the CKD population [26]. The decision to perform endovascular revascularization in CKD is complicated by the occurrence of contrast nephropathy (see Risk of Contrast-Based Imaging Studies in Special Considerations section below). Complete vascular assessment of lesion anatomy, location, and contrast load needed allow designing an individualized strategic plan which includes optimization of catheter manipulation as well as contrast doses during endovascular interventions. Successful procedural outcomes and improved long-term patency vary directly with lesion location and categorization as classified by the TASCII guidelines. A retrospective study that evaluated 535 patients undergoing endovascular therapy for superficial femoral artery (SFA) disease found significantly worse tibial runoff and limb salvage rates in the GFR ≤60 mL/min/1.73 m² group compared to those with better kidney function [27]. Over 50 % of the patients in the GFR <60 mL/min/1.73 m² group had manifestations of CLI at the time of endovascular therapy. The factors associated with poor limb salvage were tissue loss at presentation, presence of diabetes, congestive heart failure, embolization at time of intervention, 0 or 1 vessel tibial runoff, and progression of distal disease at follow up. Another study on 107 dialysis patients reported a technical success of 96 %, with limb salvage rates at 1, 2, 3, and 4 years of 86 %, 84 %, 84 % and 62 %, respectively. Similarly, good primary patency rates were also reported in studies that evaluated iliac-femoropopliteal [24] and infrapopliteal [28] angioplasties in ESRD patients .

Certain clinical and angiographic features may promote improved long-term outcomes and greater freedom from amputation after endovascular therapy. Unfortunately, the existing literature is scant in this regard. In one small case series of 55 diabetic patients on hemodialysis who underwent an endovascular revascularization for CLI, the clinical presentation was noted, including classification of ulcers using the Wagner criteria (Table 50.3) [29]. Forty-six limbs were classified as Wagner grades 4 or 5 upon presentation. Patients presenting with rest pain did not require amputation. Those with healing ulcers showed similar rates of limb loss at 12 months, approaching 60 % compared to those without ulcers. These and other emerging data show improved amputation-free survival and rates of limb salvage with revascularization in persons with CLI at all levels of renal impairment [30]. A feature typically seen in advanced kidney disease is heavy calcification of the distal vessels, which tend to be smaller in caliber (Fig. 50.1), and multilevel disease (Fig. 50.2) , including SFA and popliteal arteries. As a result, surgical bypass targets may be limited. With the evolution of endovascular techniques, more dedicated devices and equipment have become available to deal with infrapopliteal disease. Chronic total occlusions, CTOs, are a common feature. Lesion length varies inversely with the likelihood of successful recanalization. Adventitial calcium may prevent guide wire reentry when attempting an extraluminal recanalization. To facilitate lesion crossing, newer wires are available with heavier tips (up to 20 gms) which are better able to pierce the proximal or distal lesion caps. These caps tend to be heavily calcified and fibrotic and present the initial challenge with true lumen crossing. Newer hydrophilic, or polymer-coated, wires are lubricious enough to find and navigate microchannels. Access from a retrograde approach via the dorsalis pedis artery, which can be accessed using ultrasound guidance, may facilitate true lumen crossing. Using an antegrade approach via a direct SFA puncture or retrograde approach via dorsalis pedis artery, may allow for greater maneuverability of balloons, or support catheters. Some novel reentry devices incorporate intravascular ultrasound imaging; however, their utility in the treatment of patients with advanced CKD needs to be established .

Balloon angioplasty with a residual lesion <30 % remains the gold standard definition of success for peripheral vascular interventions. However, the restenosis rates remain high and peripheral artery stenting has been adapted from the experience in the coronary world with hopes of overcoming the restenosis problem, for which diabetes is a known risk factor. Stents used in peripheral interventions may be self-expanding nitinol, balloon expandable, bare metal, or drug eluting. Stenting however remains controversial due to the concerns that stents can fracture with lower extremity movements and may also eliminate future bypass targets and injure collaterals. In the short term, dual antiplatelet therapy may be necessary to prevent occlusion. This is of concern in patients with CKD and ESRD who may be at increased risk for bleeding complications. However, if significant lesion recoil occurs after deflation of the balloon, a stent may be the only viable solution to keep the artery open and more importantly keep inline flow adequate. Most trials of endovascular stenting for CLI treatment did not recruit significant numbers of CKD and ESRD patients. Also, a common contraindication to stenting in trials was lack of vessel runoff or only one vessel runoff with 50 % lesion present, both of which are common in persons with advanced kidney disease.