Residency · Residency · Vascular Surgery

Femoropopliteal Disease: Endovascular Approaches

Overview

The superficial femoral artery (SFA) and popliteal artery represent the most common sites affected by lower extremity atherosclerotic occlusive disease. The SFA is particularly vulnerable due to its anatomical course through the adductor canal, where it is subject to extrinsic compression. Additionally, its long length and limited collateral circulation contribute to its susceptibility. Endovascular therapy has become the first-line treatment for many femoropopliteal lesions, although maintaining long-term durability remains a significant challenge. Treatment options include balloon angioplasty, bare metal stents, drug-coated balloons, drug-eluting stents, and atherectomy.

Anatomy

The SFA originates at the bifurcation of the common femoral artery and travels through the thigh within the subsartorial or adductor (Hunter) canal. It transitions into the popliteal artery as it passes through the adductor hiatus. The popliteal artery is anatomically divided into three segments: P1 lies above the knee joint, P2 corresponds to the level of the knee joint, and P3 extends below the knee joint to the trifurcation. The deep femoral artery, also known as the profunda femoris, plays a crucial role by providing collateral pathways that become especially important when the SFA is occluded.

TASC II Classification (Femoropopliteal)

The TASC II classification system categorizes femoropopliteal lesions based on their complexity. TASC A lesions involve a single stenosis of 10 cm or less or a single occlusion of 5 cm or less. TASC B lesions include multiple stenoses or occlusions each measuring 5 cm or less, or a single stenosis or occlusion up to 15 cm that does not involve the below-knee popliteal artery. TASC C lesions consist of multiple stenoses or occlusions totaling more than 15 cm or recurrent stenoses following two prior interventions. Finally, TASC D lesions represent chronic total occlusions of the common femoral artery (CFA), SFA, or popliteal artery exceeding 20 cm and involving the popliteal segment.

Endovascular Techniques

Vascular Access

The most common vascular access approach is contralateral femoral access with crossover to the target limb. Antegrade ipsilateral femoral access provides a more direct route with a shorter working distance. When antegrade crossing of occlusions fails, retrograde access via the popliteal or tibial arteries can be employed. Radial access is increasingly utilized for interventions involving the iliac artery or proximal SFA.

Lesion Crossing Strategies

Lesion crossing is ideally performed intraluminally, which preserves the true lumen of the vessel. When intraluminal passage is not feasible, subintimal crossing is an alternative, involving the creation of a dissection plane between the media and adventitia layers of the vessel wall. The Bolia technique is a form of intentional subintimal angioplasty. Re-entry devices such as the Outback and Pioneer systems facilitate re-entry into the true lumen after subintimal passage. Retrograde crossing via pedal or popliteal puncture serves as a valuable bailout strategy when antegrade attempts are unsuccessful.

<image>Diagram illustrating intraluminal versus subintimal crossing techniques for SFA chronic total occlusion, showing guidewire trajectory through the true lumen versus the subintimal dissection plane with re-entry device deployment</image>

Plain Balloon Angioplasty (PTA)

Plain balloon angioplasty has historically been the mainstay of endovascular treatment and remains a baseline comparator. Its mechanism involves controlled plaque fracture and vessel stretching. However, primary patency rates for femoropopliteal lesions after PTA alone range from only 40 to 60% at one year, which is generally considered inadequate for longer lesions. PTA is acceptable for short, focal stenoses but is limited by common complications such as elastic recoil and flow-limiting dissections.

Bare Metal Stents (BMS)

Self-expanding nitinol stents are the standard for the femoropopliteal segment because they accommodate vessel flexion and compression. Examples include the Innova, Complete SE, and Absolute Pro stents. Balloon-expandable stents are generally avoided in the SFA due to poor fracture resistance. BMS improve patency compared to PTA alone for lesions longer than 4 to 5 cm. However, stent fracture remains a significant concern in the SFA and popliteal artery, with risk factors including longer stent length, placement across the knee joint, and overlapping stents. Stent fractures can lead to restenosis and occlusion. Primary patency rates for moderate-length lesions treated with BMS range from 60 to 75% at one year.

Drug-Coated Balloons (DCB)

Drug-coated balloons are coated with an antiproliferative drug, typically paclitaxel, which is delivered locally to the vessel wall during balloon inflation. This approach targets intimal hyperplasia, the primary mechanism of failure after PTA. Leading DCB platforms include the IN.PACT Admiral and Lutonix devices. DCBs demonstrate superior primary patency compared to PTA, achieving rates between 70 and 85% at one year. The IN.PACT SFA trial reported an 82.2% primary patency at one year with DCB versus 52.4% with PTA. DCBs are particularly advantageous when stent placement is undesirable, supporting a "leave-nothing-behind" strategy.

Drug-Eluting Stents (DES)

Drug-eluting stents combine a self-expanding nitinol scaffold with a polymer-based paclitaxel coating. The Zilver PTX stent is the only FDA-approved DES for femoropopliteal use. These stents achieve primary patency rates of 74 to 83% at one year and may be used either as primary therapy or as provisional stenting following failed PTA or DCB treatment.

Covered Stent Grafts

Covered stent grafts consist of ePTFE-encapsulated nitinol stents, such as the Viabahn device. They are useful for long-segment disease, in-stent restenosis, and aneurysmal disease. The VIASTAR trial demonstrated that Viabahn stent grafts outperform bare metal stents for long SFA lesions exceeding 15 cm. However, concerns remain regarding edge stenosis and occlusion of side branches. These devices must be deployed with landing zones in healthy vessel segments to optimize outcomes.

Intravascular Lithotripsy (IVL)

Intravascular lithotripsy employs a shockwave balloon that delivers sonic pressure waves to fracture vascular calcium. This technique facilitates effective angioplasty of heavily calcified vessels while preserving vessel architecture. IVL is emerging as an important adjunctive therapy prior to DCB or stent placement.

<image>Comparison of endovascular device options for femoropopliteal disease showing cross-sectional views of plain balloon angioplasty, drug-coated balloon, bare metal self-expanding stent, drug-eluting stent, and covered stent graft in the SFA</image>

The Paclitaxel Controversy

In 2018, a meta-analysis by Katsanos and colleagues suggested an increased risk of all-cause mortality at two and five years following the use of paclitaxel-coated devices in femoropopliteal interventions. This finding sparked significant debate and led to temporary regulatory scrutiny. Subsequent analyses, including the SWEDEPAD trial, found no mortality signal in randomized populations. The FDA concluded that current data do not support a causal relationship between paclitaxel devices and increased mortality but recommended ongoing long-term surveillance. Individual patient-level meta-analyses also failed to demonstrate a significant difference in mortality. The current consensus supports the continued use of paclitaxel-coated devices, with informed consent discussions addressing the controversy.

Atherectomy Devices

Atherectomy devices are often used as adjuncts for vessel preparation before DCB or stenting, although evidence supporting their superiority over PTA or DCB alone is limited. Various types include directional atherectomy (SilverHawk/TurboHawk), rotational atherectomy (Jetstream), orbital atherectomy (CSI), and laser atherectomy (Turbo-Elite). Detailed coverage of atherectomy is available in a dedicated topic.

Outcomes by Lesion Complexity

Outcomes vary according to lesion type and the chosen treatment modality. For short stenoses less than 5 cm, PTA or DCB achieve primary patency rates between 70 and 85% at one year. Moderate-length lesions (5 to 15 cm) respond well to DCB or DES, with patency rates of 70 to 80%. Long lesions exceeding 15 cm are best treated with covered stents or DES, yielding 60 to 75% patency. Chronic total occlusions typically require stenting (BMS, DES, or covered), with 55 to 70% patency. In-stent restenosis is managed with DCB or covered stents, achieving 60 to 75% patency. Heavily calcified lesions benefit from IVL combined with DCB or atherectomy plus DCB, resulting in 65 to 80% patency.

Popliteal Artery Considerations

Stenting across the knee joint increases the risk of stent fracture, making stenting in the popliteal artery controversial and generally best avoided when possible. In the P1 and P2 segments of the popliteal artery, PTA or DCB are preferred. Covered stents such as Viabahn may be considered for P1 popliteal aneurysms.

Clinical Pearls

Before treating the femoropopliteal segment, it is essential to assess both inflow vessels, including the iliac arteries and common femoral artery, as well as outflow through the tibial runoff. The profunda femoris artery serves as the "lifeline" of the leg and should always be preserved or restored if compromised. Stent length is an important consideration; unnecessary stenting should be avoided, favoring a "leave-nothing-behind" strategy whenever possible. Drug-coated balloons are ideal for lesions where stenting is undesirable, such as across joints or in younger patients. Subintimal crossing techniques provide valuable bailout options but may compromise future surgical targets. Completion imaging with angiography or intravascular ultrasound (IVUS) is necessary to confirm an adequate procedural result. Dual antiplatelet therapy is typically continued for one to three months after femoropopliteal stenting, with longer durations recommended for drug-eluting stents.

<image>Angiographic sequence showing pre-intervention chronic total occlusion of the SFA, crossing with a guidewire, drug-coated balloon inflation, and post-intervention angiogram demonstrating restored flow with no residual stenosis</image>

References

• Laird JR, et al. Durability of treatment effect of the IN.PACT Admiral drug-coated balloon: 3-year results. JACC Cardiovasc Interv. 2019;12(12):1086-1095.
• Dake MD, et al. Zilver PTX drug-eluting stent: final 5-year results. JACC Cardiovasc Interv. 2016;9(12):1256-1264.
• Katsanos K, et al. Risk of death following application of paclitaxel-coated balloons and stents in the femoropopliteal artery of the leg: a systematic review and meta-analysis. J Am Heart Assoc. 2018;7(24):e011245.
• Nordanstig J, et al. Drug-coated balloon vs. uncoated balloon in the SFA and popliteal artery (SWEDEPAD). N Engl J Med. 2023.
• Lammer J, et al. Heparin-bonded covered stent vs. bare metal stent for femoropopliteal disease (VIASTAR). Eur J Vasc Endovasc Surg. 2013;45(4):370-376.
• Rocha-Singh KJ, et al. Peripheral arterial calcium: review and clinical implications. Catheter Cardiovasc Interv. 2014;84(2):245-253.

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