Stenting the Chronic Totally Occluded Superficial Femoral Artery: Endovascular Clinical Benefit

Peripheral vascular disease (PVD) has been described as underreported, underdiagnosed and undertreated in this country. Clinical and epidemiological studies suggest the prevalence of PVD is higher than previously believed and could be over 20% in the general population.¹ Classically, lower extremity claudication involves the superficial femoral artery (SFA). It can be the sole level or be a part of multilevel disease in claudicants or critical limb ischemia respectively.² Importantly, the SFA remains one of the most uniquely dynamic arteries in the arterial tree, as it undergoes tremendous external and internal torsion forces in its daily activity.² Because of this, various endovascular approaches to its therapy have met with both positive and negative results. Historically, treatment of lower extremity claudication was limited by medical therapy (best treatment is aspirin alone) with an exercise walking program^3–7 or aggressive surgical revascularization through femoral-popliteal bypass.^8,9 More recently, percutaneous endovascular approaches have become popular as has aggressive medical therapy to include dual antiplatelet therapy (ASA with ADP inhibitors) and high-dose statins or other lipid-lowering agents. Treatment for focal disease in the SFA is currently accepted via an endovascular method to include simple balloon angioplasty, stenting, cryoplasty, directional atherectomy or continued medical therapy as first-line therapy.^3,10,11 As the lesion length increases, endovascular therapy fails to maintain patency compared with the surgical standards reported in the past. Moreover, problems with chronic total occlusions (CTOs) patency have been abysmal, with patency rates for angioplasty alone being 20–30%, or 40% with stenting at 1 year.³ The current manuscript by Dippel et al¹⁴ is a small study of 44 patients treating 51 limbs, and suggests a clinical long-term benefit of treatment of CTO SFAs at 1 year using the SMART™ nitinol stent by Cordis Corporation (Miami Lakes, Florida). The disease treated was considered TransAtlantic InterSociety Consensus (TASC) D by description and was relatively long at 15 cms. Treatment involved 2.7 stents per lesion, with the stented length being 23 cm. Success was attained acutely in 91% of patients, with 1 patient experiencing acute thrombosis that required emergent repeat intervention. Most patients in the study were claudicants (88%), and only a few went on to have limb loss after 1 year of follow up (though none of these limb-loss patients were described as having critical limb ischemia prior to intervention). The benefits of this study suggest endovascular intervention of the SFA CTO is a feasible approach that offers a nonsurgical therapy to patients with moderate-to-severe claudication. Quality of life questionnaires such as the WIQ showed acute and sustained benefit for patients who underwent successful revascularization. Clearly, this first in a long line of first steps continues to confirm the utility and benefit of treating peripheral arterial disease with an endovascular approach. Indeed, even with the most difficult of cases as shown here, the long total occlusion can be treated aggressively and with great clinical success. However, there are several key limitations with this study. First, it is a small study of only 51 lesions. The authors do not describe the calcific nature or additional unfavorable features of the lesion subset they treated. Further, the average number of stents was 2.7 per lesion. Various studies, including SIROCCO and FESTO^12,13 suggest that stent fracture rates, even with the Cordis SMART stent, increases with a higher number of stents used, and can be as high as 37%.¹³ Stent fracture rates are directly proportional to restenosis rates. The restenosis rates in SIROCCO I were 40% at 1 year, and were directly attributable to the fracture sites. The authors did not report their stent fracture rates in this patient cohort, though their primary endpoint was a clinical quality of life evaluation. Also, the clinical endpoint of WIQ and ankle-brachial indices (ABI) remain soft clinical endpoints. Though important measures of clinical benefit, they do little to demonstrate vessel patency. Moreover, care should be given to comparisons with historic surgical patency rates based on duplex imaging not employed here. Thus, the manuscript by Dippel et al is an important first step to evaluate endovascular SFA CTO outcomes. Endovascular therapy for the SFA is important and should be considered the first step for most if not all patients with TASC A through the most difficult TASC D lesions. The “science” of what we do has yet to be defined or even broadly accepted. Although this manuscript is a great first step to that end, further steps must yet be taken.

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