Case presentation

A 74-year-old diabetic man with hypertension and prior tobacco use, whose medications included aspirin, a statin, and an ACE inhibitor, developed bilateral calf claudication. Eventually, his leg symptoms progressed and he was unable to exercise, greatly limiting his lifestyle. His physician detected diminished pulses distally and assessed these symptoms with noninvasive studies (Figure 59-1). These demonstrated moderate bilateral arterial insufficiency at the level of the superficial femoral artery (SFA). He was referred for angiography.

FIGURE 59-1 Preprocedure noninvasive studies demonstrating bilateral disease at the level of the superficial femoral arteries.

Angiography

The patient’s symptoms were worse in the left leg; thus angiography of the left leg was performed first from an arterial sheath placed in the right femoral artery. It showed high-grade, sequential lesions in the mid-SFA (not shown). These were successfully treated with a self-expanding stent. Following that procedure, diagnostic angiography of the right leg was performed and demonstrated two high-grade lesions in the SFA with an ulcerated stenosis of the proximal segment of the right SFA (Figures 59-2, 59-3) and a longer, severe stenosis in the mid- to distal segment (Figure 59-4). The patient was discharged after this procedure on the left leg and experienced resolution of his left leg claudication with normalization of his left leg noninvasive studies. However, he continued to be limited by right leg claudication. Therefore, approximately 3 months after his left leg intervention, he presented for endovascular treatment of the right leg.

FIGURE 59-2 Angiography found a severe, eccentric stenosis in the proximal segment of the superficial femoral artery (arrow).

FIGURE 59-3 This is a nonsubtracted image of the proximal stenosis in the SFA.

FIGURE 59-4 Complex disease in the mid- and distal segments of the right SFA (arrows).

Access was obtained from the left common femoral artery. An Omniflush catheter was used to lay out the iliac vessels, and a 6 French long sheath was placed “up and over” from the left femoral to the right external iliac artery. An intravenous bolus of unfractionated heparin was administered to achieve a therapeutic activated clotting time of more than 250 seconds. The proximal and distal lesions were crossed with a hydrophilic glide wire. A catheter was then used to exchange the glide wire for a 0.018 inch guidewire. The distal SFA was treated first using a 5 mm diameter by 60 mm long balloon in two overlapping locations. The distal lesion was found to be difficult to expand (Figure 59-5); ultimately, the balloon appeared fully expanded at 12 atmospheres of pressure. A post balloon angiogram showed residual stenosis and elastic recoil; thus the operator deployed a 7 mm diameter by 150 mm long self-expanding nitinol stent across the extent of the distal lesions. The stent was postdilated with the 5 mm diameter by 60 mm long balloon (Figure 59-6) and the post-stent angiogram demonstrated an excellent result (Figure 59-7).

FIGURE 59-5 Balloon dilatation of the mid- to distal right SFA showing persistence of the waist in the balloon, which resolved at higher atmospheres.

FIGURE 59-6 Postdilatation of nitinol stents in the right mid- to distal SFA.

FIGURE 59-7 Angiographic result of the mid- to distal right SFA lesions after angioplasty and stenting.

The proximal stenosis was then dilated with the 5 mm diameter by 60 mm long balloon (Figure 59-8). This disrupted the plaque, but a significant stenosis remained; therefore the operator placed a 7 mm diameter by 60 mm long self-expanding nitinol stent, postdilating it with the 5 mm diameter balloon used earlier. The final angiogram found no residual stenosis or angiographic complication (Figure 59-9).

FIGURE 59-8 Balloon dilatation of the proximal SFA stenosis.

FIGURE 59-9 Final angiographic result of proximal SFA lesion after balloon angioplasty and stenting.

Postprocedural course

Following this procedure, the 6 French sheath was left in place until the activated clotting time fell below 180 seconds. Hemostasis was achieved with manual pressure followed by 4 hours of bed rest. He was discharged later that same day on aspirin and clopidogrel. At follow-up 1 month later, he had resolution of his symptoms and normalization of his noninvasive tests both at rest and after exercise (Figures 59-10, 59-11).

FIGURE 59-10 Noninvasive studies at rest 1 month postprocedure.

FIGURE 59-11 Exercise ABIs 1 month postprocedure.

Discussion

Disease of the superficial femoral artery is present in 80% to 90% of patients with claudication.¹ At the time of angiography, this vessel is often found to be completely occluded, with collateralization and reconstitution of the distal vessel from the profunda femoris. In fact, the profunda femoris is considered to be the “lifeline” to the lower leg, as the collaterals it provides are usually adequate to avoid limb-threatening ischemia. They are usually not adequate, however, to prevent claudication.

The high incidence of SFA disease may relate to the unusual forces that it undergoes, especially in the distal portion of the vessel, including flexion, torsion, compression, and extension. These forces lead to nonlaminar flow and endothelial injury, both of which can promote atherosclerosis. These forces also make endovascular therapy challenging. Traditional balloon-expandable stents cannot be used in the SFA, as they would be deformed and compressed by these same forces. Instead, self-expanding stents are employed. These are most commonly made of nitinol, which has a unique property of “memory” that allows the stent to be expanded to the size it was created, providing continual outward forces against the artery and thus resisting external compression. Typically, a stent is chosen one millimeter in diameter larger than the reference vessel diameter to allow uniform apposition and to accommodate for the dynamic forces that the stent undergoes.

There are a variety of other techniques used to treat SFA disease. These include balloon dilatation alone, scoring balloons, freezing balloons, atherectomy devices (including shaving devices, lasers, and drills), and covered stents, all of which have advantages and disadvantages and specific niche applications. However, despite all of this technology, restenosis rates of SFA lesions are typically 20% to 30% at 1 year.

As with aortoiliac disease, the TASC working group has created a classification system for femoral/popliteal disease (Table 59-1).² Again, similar to aortoiliac disease, endovascular treatment is preferred for TASC A and B lesions and surgery is preferred for TASC D lesions. TASC C lesions are usually treated surgically unless the patient is a poor surgical candidate, although endovascular approaches are reasonable in some patients as long as the intervention does not “burn any bridges” regarding future surgical options. The lesions presented in this case would be considered TASC B as there were multiple SFA lesions which individually were less than 5 cm each (the distal SFA lesion was actually two lesions that were treated as one).

TABLE 59-1 TASC Classification of Femoropopliteal Disease²

Above-the-knee surgical bypass with autologous vein or prosthetic material has acceptable 5-year patency rates, typically approaching 75%. The outcome after surgery also depends on the status of the inflow and outflow vessels as well as the presence of a healthy section of distal artery to receive the anastomosis. Restenosis remains a significant issue for femoropopliteal lesions and there are a variety of options available if restenosis occurs, including balloon angioplasty, debulking techniques (laser, shavers, drills), restenting, and restenting with a covered stent. There are few data available comparing the outcomes of these various strategies. Patients with recurrent restenosis and significant symptoms should be considered for surgical bypass. It is important for the interventionalist to keep this in mind so as to not limit future surgical options by placing stents in locations where a distal surgical anastomosis may be necessary.