Femoropopliteal atherosclerotic occlusive disease is frequently responsible for Rutherford category 3-6 lower-extremity peripheral artery disease. The Trans-Atlantic Inter-Society Consensus (TASC) II class D femoral/popliteal lesions include chronic total occlusions (CTOs) of the superficial femoral arteries (SFAs) that are >20 cm or involve the popliteal artery.1 Currently, femoropopliteal bypass surgery is recommended as the first-line revascularization strategy in TASC II class D SFA-CTOs over endovascular therapy (EVT).1,2 This recommendation stems from early challenges of EVT in successfully crossing long, frequently calcified SFA-CTOs and, importantly, the associated lower and variable long-term patency rates after percutaneous revascularization. Historically, EVT for these complex lesions consisted of the traditional antegrade or bidirectional approach, frequently with a subintimal wire loop technique described in 1989 by Bolia et al,3 followed by angioplasty and stenting after intraluminal reentry. Vascular wall disruption, micro- and macro-dissections, small-caliber vessels, long lesion lengths, and diffuse calcified disease are contributors to the poor patency rates in this complex vascular bed. Recent technological advances in EVT have extended the applicability of minimally invasive, percutaneous treatment of challenging TASC II SFA/popliteal class C/D de novo lesions, which were previously deemed unsuitable for EVT. However, reduced long-term patency compared with saphenous vein bypass remains the “Achilles’ heel” of EVT, despite similar limb salvage rates, early recovery, shorter hospital stays, and lower morbidity and mortality rates compared with surgery. The patient population referred for EVT in TASC II class D lesions frequently has prohibitive surgical comorbidities, unsuitable conduits, or lack of an adequate distal target for revascularization, placing them at higher risk for unfavorable long-term results after vascular surgical bypass. Furthermore, many patients have history of diabetes and smoking, have occlusive disease, have poor run-off vessels, require limb salvage, and have concomitant ischemic heart disease and chronic kidney disease, all which increase the risk of perioperative complications and mortality, as well as affect long-term patency. Therefore, controversy continues to exist regarding the optimal method of revascularization in TASC II D SFA lesions in patients with lifestyle-limiting claudication or limb ischemia.
Optimizing EVT procedural techniques that could improve long-term patency and clinical outcomes for TASC II D lesions is therefore an important area of focus. High rates of successful recanalization exceeding 80%-90% in TASC II C/D lesions can now be achieved with advances in endovascular technology (eg, crossing and reentry devices) and improved operator skills.4 Most previous data for SFA-CTOs were based on subintimal angioplasty techniques with a 0.035˝ looped guidewire and a supporting catheter at the occlusion site, commonly via an antegrade approach. Due to its simplicity and low cost, this approach has been frequently adapted in most femoropopliteal occlusions. Once the occlusion is crossed with a guidewire, one of the main detriments to long-term EVT success in the femoropopliteal segment is restenosis, partly due to multiple biomechanical forces such as torsion, compression, stretching, flexion, and extension. Primary stenting has proven superior to percutaneous transluminal balloon angioplasty (PTA), particularly in long lesions, where 40%-50% of cases require bail-out stenting.5,6 In that regard, the newer generations of nitinol self-expanding stents have become the predominant strategy for treatment of challenging TASC II C/D SFA occlusions. However, stent placement is associated with an exaggerated neointimal hyperplastic response, which results in high in-stent restenosis rates (10%-40% at 6-24 months) and stent fractures at sites of excessive movement.7 The subintimal approach can contribute to insufficient dilation and recoil after stent placement in the subintimal space, whereas the response to balloon dilation and self-expandable stenting can be more predictable and favorable with an intraluminal approach.
A complete intraluminal strategy to percutaneous revascularization may improve patency rates and clinical outcomes relative to subintimal technique, but data on this approach have been sparse. In the current issue of the Journal of Invasive Cardiology, Matsumi et al evaluated the technique of complete intraluminal angioplasty and self-expandable nitinol stenting for TASC II D SFA-CTOs in 72 consecutive limbs of 68 patients.8 The main outcome was the rate of primary patency at several follow-up periods up to 5 years. Unique to this study was the very high rate (~70%) of bidirectional wiring to assist with true intraluminal crossing prior to angioplasty and routine stenting. The patient population had significant comorbidities, including half with diabetes, 20% on hemodialysis, and 20% with limb ischemia. The average occlusion length was 24.4 cm and ~50% of patients had a single-vessel run-off below the knee. The authors reported primary patency rates of 78% at 1 year, ~70% at 2-3 years, and 52% at 5 years. These patency rates are promising given previously published patency rates in complex TASC II D SFA lesions, reported to be ~66%-77% at 1 year, 22%-57% at 2 years, and <50% at 3 years.9-11 Moreover, the patency rates in Matsumi’s study were achieved in a cohort known to have many risk factors predictive of target-lesion revascularization, including all lesions classified as TASC D lesions, long stent lengths (25.6 cm), frequent dialysis, and few patent tibial arteries.10
Prior data for long femoropopliteal occlusions with variable patency rates after intervention included a mix of subintimal and intraluminal approaches.4 Caution should be taken, however, to attribute the higher patency rates seen in the current study solely to the intraluminal plus bidirectional approach, as there was no subintimal comparator group. The endovascular procedures using the loop technique with a 0.035˝ guidewire are considered to utilize subintimal angioplasty; however, the guidewire may not always pass and stay subintimally. This has been seen on intravascular ultrasound analysis of subintimal angioplasty lesions, where the wire was seen in the true lumen in many cases.12 Conversely, the intraluminal procedure performed using 0.014˝ and 0.018˝ guidewires can result in unintentional subintimal wire passage in some cases, as well as intentional crossover to subintimal approach in other cases. In clinical practice, intentional crossover may be common, not only in technically challenging cases, but also due to prolonged procedural time and large amount of contrast media administered. The only prior study that compared outcomes between the subintimal and intraluminal approaches, albeit retrospectively, showed no difference in 3-year primary patency rates (intraluminal 55% [n = 651] and subintimal 53% [n = 251]; P=.30).12 In addition, the crossover rate in this retrospective comparative study from the intraluminal to subintimal group was 25% and longer procedural times (intraluminal 117 minutes vs subintimal 93 minutes; P<.001) were noted.12 Furthermore, the intraluminal approach in this Japanese study was associated with greater usage of guidewires, surface sonography, and intravascular ultrasound, which resulted in higher medical costs by about $1000 per procedure. This cost difference would be even higher in United States practices, where crossing devices (for intraluminal approach) and reentry devices (for crossover) are available.
The high rate of bidirectional transpopliteal approach in this study is likely reflective of difficulty staying intraluminally with an antegrade guidewire approach. It is reassuring to see a low frequency of periprocedural complications with bidirectional approach. Other studies have confirmed that ultrasound-guided, retrograde popliteal access is safe and effective, with minimal access-site complications.13 Distal transpopliteal puncture is performed infrequently in the US due to technical difficulty in obese patients and availability and high success rates with re-entry devices. More recently, transpedal access techniques have been successfully used in patients with chronic SFA occlusions, which extends the ability to perform complex EVT after failed antegrade approach.14 Drug-coated balloons (DCB) for femoropopliteal lesions have recently demonstrated significantly higher primary patency rates at 12- and 24-months compared with PTA.15 Given that intraluminal approach may result in more favorable response to balloon angioplasty, the combination of intraluminal approach and DCB may be an attractive strategy for complex SFA occlusions. Currently, a wide spectrum of endovascular options exists once intraluminal crossing is achieved, including PTA with plain balloons, DCB, or “specialty” balloons (eg, cutting, AngioSculpt scoring, or Chocolate balloons), primary or bail-out nitinol or drug-eluting stent implantation, “specialty” stents (interwoven nitinol or PTFE-covered stents), and plaque modification by means of atherectomy.5 A prospective, multicenter, randomized trial with these contemporary devices and techniques would be needed to compare the “intraluminal” vs “subintimal” approaches in order to examine whether the added procedural time and cost would result in an effective, safe, and cost-sensitive strategy and improved long-term patency rates.
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12. Soga Y, Iida O, Suzuki K, et al. Initial and 3-year results after subintimal versus intraluminal approach for long femoropopliteal occlusion treated with a self-expandable nitinol stent. J Vasc Surg. 2013;58:1547-1555.
13. Younes HK, El-Sayed HF, Davies MG. Retrograde transpopliteal access is safe and effective — it should be added to the vascular surgeon’s portfolio. Ann Vasc Surg. 2015;29:260-265.
14. Fanelli F, Cannavale A. Retrograde recanalization of complex SFA lesions indications and techniques. J Cardiovasc Surg (Torino). 2014;55:465-471.
15. Laird JR, Schneider PA, Tepe G, et al; IN.PACT SFA trial investigators. Durability of treatment effect using a drug-coated balloon for femoropopliteal lesions: 24-month results of IN.PACT SFA. J Am Coll Cardiol. 2015;66:2329-2338.
From the Greenberg Division of Cardiology, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.
Address for correspondence: Dmitriy N. Feldman, MD, Director of Endovascular Services, Associate Professor of Medicine, Division of Cardiology/Department of Medicine, Interventional Cardiology and Endovascular Laboratory, Weill Cornell Medical College/New York Presbyterian Hospital, 520 East 70th Street, New York, NY 10021. Email: email@example.com