The problem of claudication is almost entirely limited to patients with atherosclerotic disease who have symptoms related to the lower extremities. Claudication can also occur in large vessel vasculitides, such as Takayasu and giant cell arteritis, which typically involves the arms. The role of percutaneous intervention has been less well studied in these disorders and there is the belief that angioplasty in case of arterial narrowing secondary to an inflammatory disorder is associated with an increased risk of early and late recurrences.
3.4.1 Role of Revascularization for Claudication
Because of the variability of individual limb ischemic symptoms and variable impact of these symptoms on quality of life, patients should be selected for revascularization on the basis of the severity of their symptoms; a significant disability as assessed by the patient; failure of medical therapies; lack of significant comorbid conditions; vascular anatomy suitable for the planned revascularization; and a favorable risk/benefit ratio.
Patients selected for possible revascularization may then undergo additional imaging studies as required, such as duplex ultrasound, MRA or CTA, and/or catheter angiography, to determine whether their arterial anatomy is suitable for percutaneous or surgical revascularization.
3.4.2 Indications for revascularization
The ACC/AHA and the TASC II guidelines suggest that the following issues need to be addressed when considering either percutaneous or surgical revascularization in patients with intermittent claudication (2, 3):
The patient has not had or is not predicted to have an adequate response to exercise rehabilitation and pharmacologic therapy,
The patient is significantly disabled by claudication, resulting in an inability to perform normal work or other activities that are important to the patient. This criterion reflects the variability among patients of the symptoms of claudication and of the impact of these symptoms on the quality of life. Of note, before the final decision of a conservative or a revascularization attitude, one should remember that, there may be substantial differences between patient and physician assessments of the quality of life impairment caused by the claudication (173, 174).
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The patient is able to benefit from an improvement in claudication (i.e., exercise is not limited by another cause, such as angina, heart failure, chronic obstructive pulmonary disease, or orthopedic problems).
The projected natural history and prognosis of the patient.
The characteristics of the lesion permit appropriate intervention at low risk with a high likelihood of initial and long-term success.
3.4.3 Endovascular Treatment for Claudication
Endovascular techniques to treat peripheral arterial occlusive disease include PTA with balloon dilatation, stents, atherectomy, laser, cutting balloons, thermal angioplasty.
Endovascular (and surgical) treatments can be selected on the basis of morphological features that stratify lower extremity arterial anatomy into subgroups: - iliac lesions; - femoro-popliteal lesions;
below the knee (i.e. infrapopliteal) lesions.
Outcomes of PTA and stents depend on anatomic and clinical factors. Durability of patency after PTA is greatest for lesions in the common iliac artery and decreases distally. Durability also decreases with increasing length of the stenosis/occlusion, multiple and diffuse lesions, poor quality runoff, diabetes, renal failure, smoking, and CLI (175-179).
Percutaneous transluminal angioplasty of vein bypass graft stenoses has also been reported, with 1- to 3-year patency of the treated site of approximately 60% (180, 181), comparable to that for surgical repair (180). Percutaneous transluminal angioplasty of multiple vein graft stenoses has a much lower 3-year patency suggesting that patient’s selection is the key in obtaining satisfactory outcomes (182).
Selection of lesions for endovascular versus conservative therapy is not well defined. An ilio-femoral stenosis is generally considered hemodynamically significant if the luminal stenosis on angiography is ≥70% (3). Stenoses of 50% to 70% diameter by angiography may or may not be hemodynamically significant, and intravascular pressure measurements have been recommended to determine whether these lesions are significant and to predict patient improvement if the lesion is treated (183). Unfortunately, there is no consensus on a diagnostic transstenotic pressure criteria or on methods to measure these pressures (184). The most used criterion utilizes a mean gradient − as measured with a 4F or 5F diagnostic catheter − of 10 mm Hg before or of 15 mm Hg after vasodilators (183, 185). Of note, the summation of multiple intermediate lesions (i.e. 50-70% of stenosis) may
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cause an even more important pressure gradient than that observed in case of an isolated more severe stenosis (i.e. 90%).
3.4.4 Cost-effectiveness of Endovascular Treatments for Claudication
In order to remain cost-effective, especially by treating claudicant patients, the proposed treatment should be efficacious, durable, relatively inexpensive and associated to a low rate of procedural related complications. For all these reasons, the endovascular approach by claudicant patients, which most of the time may be performed in an ambulatory setting, seems very attractive.
Accordingly, a cost-effectiveness analysis compared PTA and bypass surgery with exercise therapy for treatment of claudication. The cost-effectiveness of PTA was $38’000 per quality-adjusted life year, which is in the range of other accepted procedures, while bypass surgery cost-effectiveness was $311’000 per quality-adjusted life-year (186).
Effectiveness is strongly affected by the severity of patient symptoms before revascularization and severity of disease. For femoral-popliteal disease, PTA was more cost-effective than surgical bypass for the treatment of claudication (stenosis and occlusion) and for treatment of CLI (stenosis only) while surgical bypass was more cost-effective for treatment of CLI for long SFA occlusions (187).
Selection of patients for femoral-popliteal artery PTA or stenting has been assessed in several randomized trials and meta-analysis of case series. The meta-analysis concluded that only for
treatment of occlusions in patients with CLI was there a suggestion that stents were more durable than PTA alone (139). For all these reasons, a primary balloon angioplasty approach followed by a bailout stenting only in case of unsatisfactory results (i.e. extensive dissection, residual stenosis >50%, important elastic recoil, etc) seems reasonable for a first intervention for claudicant patients presenting with a femoro-popliteal disease (141).
Other techniques of endovascular revascularization have shown so far no advantages over PTA/stents (188-191), with only the almost abandoned endovascular brachytherapy which has shown to reduce restenosis rates of PTA and stenting in the femoral-popliteal arteries (192, 193), at the price of an increased risk of late acute thrombotic occlusions, especially in the presence of a stent (194).