Endovascular Treatment of Peripheral Artery Disease

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Chapter 20 Endovascular Treatment of Peripheral Artery Disease

The concept of nonsurgical catheter-based peripheral vascular revascularization was first described by Charles Dotter ¹ and further advanced with the development of balloon dilation catheters by Andreas Gruentzig.² Catheter-based revascularization has largely replaced conventional open surgery as the treatment of first choice in selected patients treated for lower-extremity ischemia.³

No single specialty program (cardiology, radiology, or surgery) offered training that satisfied the entire skill set needed to perform peripheral endovascular intervention (Table 20-1). Recognition of this unmet need for a trained cadre of clinicians to care for patients with peripheral artery disease (PAD) prompted the development of a core cardiology training symposium (COCATS-11) to codify the necessary cardiology fellowship training.⁴

^{Table 20-1} Required Skill Elements for Optimal Peripheral Vascular Intervention

Skill Element	Description
Cognitive	Extensive knowledge of vascular disease, including natural history, pathophysiology, diagnostic methods, and treatment alternatives
Technical	Competence in both diagnostic angiography and interventional techniques, such as use and selection of balloons, guidewires, stents, and emboli protection devices
Clinical	Ability to manage inpatients, interpret laboratory tests, obtain informed consent, assess risk/benefit ratio, and admitting privileges

Patient and Lesion Selection Criteria

Indications

Anatomical and Functional Criteria

Patient selection for catheter-based vascular intervention depends upon both anatomical and functional criteria (Table 20-2). Anatomical lesion criteria include ability to gain vascular access, a reasonable likelihood of crossing the lesion with a guidewire, and the expectation that a therapeutic catheter can be advanced across the target lesion (Fig. 20-1). A strategy of “provisional” (bailout) stenting, or use of a stent for a failed balloon dilation attempt (in contrast to “primary” stenting, in which stents are placed with or without balloon predilation), has become the standard of practice for shorter, more discrete lesions. Longer lesions and occlusions are better treated with primary stent placement.^3,⁵^–⁸

Table 20-2 Classification of Peripheral Arterial Disease: Fontaine’s Stages and Rutherford’s Categories

Figure 20-1 A, Tight stenosis of infrarenal aorta amenable to angioplasty. B, Final postangioplasty result.

Availability of endovascular stents (balloon expandable and self-expanding) has significantly extended the anatomical subset of patients who may be considered candidates for peripheral vascular intervention, particularly for longer stenotic lesions and occlusions. The rate-limiting step for nonsurgical revascularization of the aortoiliac vessels is the ability to pass a guidewire across the lesion. Regardless of the balloon dilation result, the option of stent placement offers a reliable and reproducible method to recanalize these large vessels.⁹

Vascular access site complications following catheter-based procedures often can be treated with percutaneous therapy ¹⁰ (Fig. 20-2). Patients with hypotension and a high suspicion of bleeding after common femoral artery (CFA) access require urgent diagnostic angiography from the contralateral femoral artery to determine the bleeding site. Rapid identification of the bleeding site may provide an opportunity for lifesaving hemostasis with balloon tamponade.

Figure 20-2 Access site complication with bleeding (A) successfully tamponaded with balloon inflation (B), and final angiogram showing hemostasis.

Functional criteria to select patients for peripheral endovascular revascularization typically include lifestyle- or vocational-limiting symptoms of claudication, critical limb ischemia (CLI; rest pain, nonhealing ulcers, or gangrene), or acute limb ischemia. Asymptomatic patients with anatomically suitable iliac artery lesions may be considered candidates for peripheral vascular intervention to facilitate vascular access, such as for intraaortic counterpulsation balloon placement or for vascular access to perform coronary intervention.

Patients with lifestyle-limiting symptoms of classical claudication or atypical claudication should first have an attempt at pharmacological therapy with cilostazol and supervised exercise training before endovascular intervention is attempted. If exercise training and pharmacotherapy are not effective, if patients are intolerant of cilostazol or cannot be treated with the drug because of heart failure (black box warning), or if a supervised exercise program is unavailable, an attempt at endovascular intervention is appropriate. In general, patients with claudication progress to limb loss at a rate of well under 5% per year, so endovascular revascularization is reserved for those patients with favorable anatomy who either fail conservative therapy and have lifestyle-limiting symptoms or have vocational-limiting symptoms. Therapeutic goals for claudicants are symptom relief, increased walking distance, and improved functionality and quality of life. For this reason, durability of the procedure becomes important; recurrent ischemic symptoms require repeated procedures.

Patients with CLI or limb-threatening ischemia (gangrene, nonhealing ulcer, or rest pain) are candidates for urgent revascularization. When considering a patient with CLI for revascularization, it is important to remember that multilevel disease (iliac, femoral, and tibial) is likely to be present and that simply improving “inflow” without addressing the more distal vascular lesions or runoff vessels may fail to solve the clinical problem. Patients with CLI (rest pain, nonhealing ulcers, or gangrene) typically have more extensive disease than claudicants and require urgent revascularization to prevent tissue loss ^3,¹¹ (see Table 20-2).

Prognosis for patients presenting with CLI is poor.¹² Those with tobacco abuse and/or diabetes are 10 times more likely to require amputation. Patients with CLI tend to be older, with almost 50% of patients older than 80 years undergoing amputations. Within 3 months of presentation, 12% will require an amputation, and 9% will die; 1-year mortality rate is 22%. Anatomy suitable for endovascular therapy is often present in one or more below-knee vessels. Therapy should be designed to restore pulsatile straight-line flow to the distal part of the limb, with as low a procedural morbidity as possible. The guiding principle is that less blood flow is required to maintain tissue integrity than to heal a wound, so restenosis does not usually result in recurrent CLI unless there has been repeated injury to the limb. Therefore, the emphasis is less on long-term vessel patency and more on amputation-free survival.

The Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial was a multicenter randomized trial comparing an initial strategy of balloon angioplasty to open surgery in 452 patients with CLI.¹³ The primary outcome was time to amputation or death (amputation-free survival). After 6 months, the two treatment strategies did not differ significantly in amputation-free survival. There was no difference between the groups for quality-of-life outcomes, but for the first year of follow-up, costs associated with a surgery-first strategy were higher than for angioplasty. For this reason, the authors concluded that a percutaneous-first strategy was the treatment of choice in patients who are candidates for either surgery or endovascular intervention.

Contraindications

Relative contraindications to catheter-based peripheral vascular intervention include (1) lesions likely to generate atheroemboli and (2) lesions that are not dilatable. Other relative contraindications include any other instances in which risks of the procedure seem to outweigh potential benefits. For example, the risk of contrast-induced nephropathy in a patient with severe renal impairment must be weighed against expected functional improvement.

Technical and Procedural Considerations

Preprocedure

General Measures

Prior to performing peripheral endovascular intervention, the patient should have a complete cardiovascular evaluation, with specific attention directed to the status of atherosclerotic risk factors. Atherosclerosis is a systemic disease, and appropriate risk-factor modification (tobacco-cessation counseling, treatment of lipids to target values), screening tests for cardiovascular diseases, and optimization of medical therapy should be performed.

Prior to performing lower-extremity endovascular intervention, it is necessary to objectively determine the patient’s functional status. A history, physical examination, and appropriate noninvasive testing should be obtained prior to planning peripheral endovascular revascularization. If the patient is ambulatory, a rest and exercise ankle-brachial index (ABI) should be measured, and pulse volume recordings (PVR) should be performed. Other noninvasive modalities, such as vascular ultrasound, or alternative imaging modalities, such as magnetic resonance angiography (MRA) or computed tomographic angiography (CTA), may be helpful to resolve conflicting data and are used at the discretion of the physician (Fig. 20-3). When planning lower-extremity revascularization, status of the inflow and outflow vessels relative to the target lesion must be visualized angiographically. This is usually done with invasive diagnostic angiography, but in selected patients, MRA or CTA may be very useful.

Figure 20-3 Computed tomographic angiogram (CTA) of lower-extremity vasculature.

There is occlusion of arterial segments of the right femoral, popliteal, and tibial segments.

Premedication

The only premedication requirement for peripheral endovascular intervention is aspirin therapy (81-325 mg daily). Use of other antiplatelet agents is optional, since there is no evidence that their use improves procedural success or decreases complications. If the patient is intolerant to aspirin, a thienopyridine drug would be appropriate. There is no evidence supporting use of dual antiplatelet therapy after peripheral endovascular intervention or following peripheral vascular stent placement.

Procedure

Anticoagulation

There is no standard for anticoagulation therapy, except to state that intravenous unfractionated heparin (UFH), in a dose up to 5000 International Units, is commonly used to achieve an activated clotting time (ACT) of 250 to 300 seconds. At present, there is no evidence that use of glycoprotein (GP)-IIb/IIIa platelet receptor antagonists, low-molecular-weight heparins, or antithrombins improve procedural efficacy or safety for peripheral vascular intervention.

Vascular Access

The first step to ensure a successful procedure is to plan appropriate vascular access. The majority of peripheral endovascular intervention can be performed from multiple arterial access sites (i.e., radial, brachial, femoral, or popliteal arteries). However, cases occasionally require a specific access to achieve a successful result. Consequently, familiarity with a variety of vascular access sites and techniques is one of the most important components of the basic skill set. Ability to gain both retrograde and antegrade common femoral access is a required skill for the interventionalist. An infrapopliteal target lesion may be best approached with antegrade femoral access, whereas a proximal superficial femoral artery lesion may require a contralateral retrograde femoral approach. Occasionally, bilateral retrograde femoral artery access is desirable—for example, when treating a common iliac bifurcation lesion.

Equipment Choices

Clinical Outcomes

Aortoiliac Vessels

The current best practice, in experienced hands, for aorto-iliac lesions favors an endovascular strategy (Fig. 20-4). This recommendation is based upon the morbidity and mortality associated with major vascular surgery in patients with significant comorbidity, and the excellent outcomes available with current endovascular techniques. In a large single-center registry of 505 iliac stent procedures, the technical success rate was 98%, 8-year primary stent patency rate was 74%, and secondary patency rate was 84%.¹⁸ In a 10-year iliac stent patency study, there was no effect of age, diabetes, tobacco smoking, or hypertension on patency.¹⁹ Common iliac artery (CIA) lesions had greater long-term patency than external iliac artery (EIA) lesions. Outcomes from another series of 89 consecutive patients with symptomatic occluded iliac arteries demonstrated a 92% success rate for endovascular treatment.²⁰ Increasing severity and complexity of lesions did not significantly alter iliac artery patency rates.

Figure 20-4 Left, Baseline angiogram of right common iliac stenosis. Right, Angiogram after angioplasty and self-expanding stent (arrows).

An observational study compared nonrandomized results of iliac artery stenting with surgery in patients with moderately complex lesions.²¹ There was no difference regarding limb salvage or patient survival out to 5 years, but vessel patency was reduced in limbs treated with stents compared to surgery. A nonrandomized retrospective comparison of endovascular intervention compared to open surgery for complex aortoiliac occlusive lesions found a shorter hospital stay, fewer postprocedural complications, and lower primary patency rates but equivalent secondary patency rates for the endovascular arm.²²

There is debate regarding the most efficacious method of endovascular therapy between “provisional stent placement,” which is selective use of stents only when balloon dilation has failed or is suboptimal, and “primary stent placement,” which is the practice of deploying a stent regardless of the balloon result. The Dutch Iliac Stent Trial demonstrated that selective iliac artery stenting achieved an equivalent hemodynamic result compared to primary stenting. Translesional pressure gradients after primary stent placement (5.8 ± 4.7 mmHg) were significantly lower than after balloon angioplasty alone (8.9 ± 6.8 mmHg), but not after provisional stenting (5.9 ± 3.6 mmHg) in the percutaneous transluminal angioplasty (PTA) group.²³ The procedural success rate, defined as a postprocedural gradient less than 10 mmHg, revealed no difference between the two treatment strategies, (primary stenting = 81% vs. PTA plus provisional stenting = 89%). By employing a provisional stenting strategy in the iliac artery, stent placement was avoided in 63% of lesions. After 5 years of follow-up, the selective stent placement strategy had greater symptomatic improvement compared with primary stent placement, but there was no difference in patency rates, ABI, and quality of life between groups.^24,²⁵

Preferred clinical practice, however, is primary stent placement, and this is supported by a meta-analysis which looked at more than 2000 patients.²⁶ Procedural success was higher in the primary stent group, and there was a 43% reduction in 4-year failures for aortoiliac stent placement compared to balloon angioplasty alone. Advantages of primary stent placement include efficient and reliable vascular reconstruction, minimizing concern over abrupt occlusion. Direct stenting minimizes the technical challenges of determining translesional pressure gradients and the need to administer vasodilator medications. The current American College of Cardiology/American Heart Association (ACC/AHA) guideline document supports primary stenting of the common and EIAs with a class I recommendation (Level of Evidence B).³

Femoral-Popliteal Vessels

Angioplasty and Stent Placement

Comparative outcomes data in femoral-popliteal artery disease are available for medical therapy, PTA, stent placement, brachytherapy, and laser angioplasty. Self-expanding stents are preferred in this location because of the risk of stent compression from external trauma. Notably absent despite their prominent position in the marketplace are comparative data for debulking atherectomy, cutting balloons, or cryoplasty.

A meta-analysis comparing angioplasty to exercise therapy in patients with intermittent claudication reported that ABI improved more with endovascular therapy than with exercise, but quality-of-life outcomes at 3 and 6 months were similar.²⁷ A cost-effectiveness study suggested that cost-effectiveness for quality-adjusted life-year was greater with percutaneous therapy than exercise alone.²⁸

A matched cohort study of 526 patients with intermittent claudication found significant advantages for a revascularization strategy (surgery or PTA) compared to medical therapy.²⁹ Revascularization was more effective than medical therapy for improvement in physical function, bodily pain, and walking distance. Patients with the greatest improvement in their ABI results had the most clinical improvement.

A recently published trial from the United Kingdom randomized 178 patients with claudication into three groups: supervised exercise, balloon angioplasty, and both if they had suitable lesions for angioplasty of the femoral-popliteal arteries.³⁰ The study demonstrated that combining supervised exercise with angioplasty produced superior clinical outcomes, but that there was no significant difference among the three groups for quality-of-life outcomes. Two main limitations of this trial were use of balloon-only treatment and the fact that the exercise time was capped at 207 meters, which may have underestimated the degree of improvement from revascularization (Fig. 20-5).

Figure 20-5 Graphic showing percent improvement in quality of life (QOL)for three randomized groups of claudicators: supervised exercise program (SEP), percutaneous transluminal angioplasty (PTA), and both.

(From Mazari FA, Gulati S, Rahman MN, et al: Early outcomes from a randomized, controlled trial of supervised exercise, angioplasty, and combined therapy in intermittent claudication. Ann Vasc Surg 24:69–79, 2010.)³⁰

Clinical success in patients with femoral artery lesions depends upon a durable long-lasting procedure. A meta-analysis demonstrated superior patency at 3 years for stents compared to PTA in the most severely affected patients, who were those with occlusions and CLI.³¹ There have been three randomized controlled trials comparing primary stenting to balloon angioplasty with bailout stenting (provisional stenting).⁶^–⁸ Lesion length and complexity accounted for restenosis rates for balloon angioplasty, but not for stent placement (Fig. 20-6). Synthesizing these results, the data suggest that longer femoral-popliteal lesions (≥ 7 cm) are better approached with a strategy of primary stenting, whereas more discrete lesions (< 4 cm) do well with a provisional stenting strategy in which balloon angioplasty is given an opportunity to stand alone (Table 20-3).

Figure 20-6 A, Baseline angiogram of distal superficial femoral artery (SFA) stenosis. B, Post-stent placement (between arrows). C, Six-month follow-up with patent SFA stent segment.

^{Table 20-3} Comparison of Primary and Provisional Femoral-Popliteal Stenting

	Schillinger	Krankenberg
Stent	Guidant	Bard
Lesion length	101 mm	45 mm
Stent restenosis	36.7%	31.7%
PTA restenosis	63.5%	38.6%*

PTA, percutaneous transluminal angioplasty.

^* P = 0.004

From Schillinger M, Sabeti S, Loewe C, et al: Balloon angioplasty versus implantation of nitinol stents in the superficial femoral artery. N Engl J Med 354:1879–1888, 2006; and Krankenberg H, Schluter M, Steinkamp HJ, et al: Nitinol stent implantation versus percutaneous transluminal angioplasty in superficial femoral artery lesions up to 10 cm in length: the Femoral Artery Stenting Trial (FAST). Circulation 116:285–292, 2007.⁵^,⁶

Stent fractures have been associated with restenosis of femoral artery lesions.³² There are differences regarding stent fracture among femoral artery stents, presumably related to their composition and architecture. Fracture rates are 28% for the SMART stent (Cordis, Miami Lakes, Fla.), 19% for the Wallstent (Boston Scientific, Natick, Mass.), and 2% for the Dynalink/Absolute (Abbott Vascular, Santa Clara, Calif.).³³

Covered Stents

Covered stents are used effectively to treat vascular perforations and exclude aneurysms in the peripheral vascular circulation. The Viabahn stent graft (W.L. Gore, Flagstaff, Ariz.) has a 1-year femoral artery patency rate of 62%. In one study, patients randomized to the Viabahn stent graft had about twice as many major adverse events (8.2%) as patients randomized to PTA (4.0%). The theoretical benefit for the Viabahn stent graft is that ingrowth of tissue between the stent struts, which plagues femoral stents, is prevented. However, edge restenosis may not be avoided, and concerns about stent thrombosis must be addressed. In one study of 60 limbs treated with a covered stent, two patients had major procedural complications requiring surgical correction. Thrombotic occlusion of the covered stent occurred in 10% of patients within 30 days, and the 1-year primary patency rate was 67%.³⁴ Late occlusion was presumed to represent edge restenosis and thrombosis. In another study, 86 patients were randomized to bypass surgery or endovascular therapy with a covered stent graft. No significant difference was observed for primary or secondary patency, but there was a trend favoring surgery for more complex lesions.^35,³⁶

Drug-Eluting Balloons and Stents

A clinical trial of a small number of patients randomized to either a bare metal self-expanding stent or a drug-eluting (sirolimus) self-expanding stent (Smart, Cordis, Miami Lakes, Fla.) found no difference in severity of restenosis.^17,³⁷ A recently completed Cook Zilver PTX trial randomized 420 patients has not reported results; however, the registry data have shown some promise.³⁸ There have been two small randomized trials of drug-coated (paclitaxel) balloons for femoral disease that have shown positive results.^39,⁴⁰ These trials found that lumen loss, restenosis, and target lesion revascularization were less after treatment with coated balloons than with uncoated balloons (Fig. 20-7). Reasons for failure of drug-eluting stents (DES) and early success for balloons in the femoral artery may be related to stent fracture and the ongoing irritant related to the metal stent against the vessel wall.⁴¹

Figure 20-7 Comparison of drug-coated balloon studies showing 6- and 24-month target lesion revascularization rates for drug-coated balloons (FEMPAC + and THUN +) versus control balloons (FEMPAC − and THUN −).

TLR, target lesion revascularization.

(From Tepe G, Zeller T, Albrecht T, et al: Local delivery of paclitaxel to inhibit restenosis during angioplasty of the leg. N Engl J Med 358:689–699, 2008; and Werk M, Langner S, Reinkensmeier B, et al: Inhibition of restenosis in femoropopliteal arteries: paclitaxel-coated versus uncoated balloon: Femoral Paclitaxel Randomized Pilot Trial. Circulation 118:1358–1365, 2008.)³⁹^,⁴⁰

Brachytherapy

Adjunctive endovascular brachytherapy (EBT) with an iridium-192 source, with a prescribed dose of 12 to 14 Gy, compared to PTA alone for treatment of de novo long-segment stenoses of the femoral artery has a delaying effect on the occurrence of restenosis.^42,⁴³ In one study, there appeared to be an early restenosis benefit for the EBT plus PTA group; however, at 5-year follow-up, there was “catch-up,” and the recurrence rate was equal (72.5%) in both groups.⁴³ Brachytherapy has greater efficacy in restenotic lesions compared with de novo lesions.^44,⁴⁵ A novel approach has been to deliver external beam irradiation to de novo femoral artery lesions after PTA. At the 1-year follow-up of one trial, there was a significant benefit for patients treated with 14 Gy in a single treatment session, compared with a control group and a group who received lower Gy doses.⁴⁶

Atherectomy

There had been expectation that by “debulking” atherosclerotic plaque, primary patency of femoral artery interventions could be improved.⁴⁷ Yet, successive generations of atherectomy catheters have failed to demonstrate any benefit over less-expensive conventional therapies.^48,⁴⁹ Comparative studies are lacking, and the data supporting the use of devices are derived from self-reported registries and subject to bias. Also, there are safety concerns regarding the incidence of distal embolization and perforation.⁵⁰^–⁵²

Laser-Assisted Angioplasty

Laser-assisted angioplasty does not appear to add any benefit to conventional endovascular therapy for peripheral arterial recanalization.^53,⁵⁴ The Peripheral Excimer Laser Angioplasty (PELA) trial randomized 251 patients to either PTA or laser-assisted PTA in patients with claudication and a total femoral occlusion. There was no difference in clinical events or patency rates at 1 year of follow-up.

Cutting Balloon

The cutting balloon is used in coronary arteries for “undilatable” lesions. There is limited evidence that would support extending the indications for this device beyond peripheral arteries,⁵⁵ and there is no evidence that a cutting balloon is an efficacious treatment for in-stent restenosis.

Cryoplasty

Clinical trials have failed to demonstrate any advantage for cryoplasty over conventional angioplasty in peripheral arterial intervention.⁵⁶ In a diabetic population with femoral-popliteal artery lesions, cryoplasty was associated with lower primary patency rates and more clinically driven repeat procedures after long-term follow-up than conventional balloon angioplasty.⁵⁷

Infrapopliteal Intervention

Tibioperoneal Angioplasty

Below-knee angioplasty has generally been reserved for treatment of CLI and threatened limbs because of the technical difficulty of using conventional peripheral angioplasty equipment in these vessels and the fear of limb loss should a complication occur (Fig. 20-8). Experience with PTA demonstrated the feasibility of a percutaneous approach with procedural success rates better than 80% for tibioperoneal angioplasty.^58,⁵⁹ Replacement of bulkier 0.035-inch equipment with the 0.014-inch devices used in coronary angioplasty improved results of below-knee intervention. In 111 patients treated with tibioperoneal angioplasty for treatment of claudication, tissue loss, or rest pain, Dorros et al.⁶⁰ reported a primary success rate of 90% for all lesions, including a 99% success rate for stenoses and a 65% success rate for occlusions. At the time of hospital discharge, 95% of patients were symptomatically improved.

Figure 20-8 Left, Baseline angiogram of severe stenosis (70%) of tibioperoneal (TP) artery. Middle, Balloon angioplasty of TP trunk. Right, Final angiogram with less than 30% stenosis. AT, anterior tibial artery; PT, posterior tibial artery; PTA, percutaneous transluminal angioplasty.

Two clinical trials have demonstrated the efficacy and attractiveness of an initial percutaneous approach to selected patients with CLI and below-knee vascular disease.^58,⁶¹ The limb salvage rate in these patients treated with PTA ranged from 85% to 91% after 2 to 5 years. This evidence supports the contention that angioplasty of the tibioperoneal vessels should not necessarily be reserved for limb salvage situations. However, caution is still advised in patient selection, since the surgical options are limited if angioplasty fails.

Optimal treatment of infrapopliteal disease requires appropriate patient and lesion selection for treatment. Focal stenoses have the best outcomes, and vessels with fewer than five separate lesions are associated with a higher success rate. Anatomically, the goal is to open as many tibial artery stenoses as possible to increase the degree of revascularization and improve clinical outcomes.⁶² Treatment success is measured by relief of rest pain, healing of ulcers, and avoiding amputation, not necessarily by long-term vessel patency. When trying to heal ischemic ulcers, the basic principle is that it takes more oxygenated blood flow to heal a wound than to maintain tissue integrity.⁵⁸ Percutaneous therapy can result in long-term limb salvage in more than 80% of patients and should be considered the current standard of treatment in patients with limb-threatening ischemia who are candidates for endovascular intervention.

Tibioperoneal Stents

The role of provisional versus primary stent placement in tibial arteries is unsettled.⁶³ A recent small randomized trial of PTA compared to PTA with a bare metal stent (BMS) demonstrated no significant differences for 1-year outcomes, including patency rates, limb salvage, or survival⁶⁴ (Fig. 20-9). Preliminary results of the use of balloon expandable coronary DES in tibial vessels have been reported.^14,^15,^65,⁶⁶ Smaller series have shown excellent patency when comparing below-knee BMS to DES.^67,⁶⁸ The largest published series is a nonrandomized report of 106 patients (118 limbs) with CLI treated with below-knee DES.¹⁵ The 3-year cumulative incidence of amputation was only 6%, and amputation-free survival was 68%.

Figure 20-9 Bar graph of 12-month patency rates comparing infrapopliteal percutaneous transluminal angioplasty (PTA) alone to PTA with bare metal stent (BMS) placement in 38 limbs with critical limb ischemia (CLI).

(From Randon C, Jacobs B, De Ryck F, Vermassen F: Angioplasty or primary stenting for infrapopliteal lesions: results of a prospective randomized trial. Cardiovasc Intervent Radiol 33:260–269, 2010.)⁶⁴