Superficial Femoral Artery Is Not Left Anterior Descending Artery
Authors: Subhash Banerjee
Journal: Circulation (2016)

he past half-decade has witnessed unprecedented improvement in outcomes for patients with peripheral artery disease subjected to mechanical endovascular therapies. 1 Once an afterthought coronary technology backwater, minimally invasive treatment of peripheral artery disease has emerged as frontline strategy for patients with medically refractory symptoms.We are now equipped with devices designed specifically for the peripheral vasculature: specialized crossing wires and catheters, debulking tools, drug-coated stents (DCSs), and drug-coated balloons (DCBs).Annual treatment failure rates are down from 20% to 30% to <3%. 2 This remarkable trend has been accompanied by equally impressive growth in our understanding of peripheral artery atherosclerosis, the result of state-of-the-art noninvasive imaging, histopathological analyses, and gene-profiling studies.Is it technology, biology, or the biology behind technology that has fueled this unrivaled success over such a short period of time?The fact that the superficial femoral artery (SFA) is located within a fibromuscular canal and is subjected to highly dynamic forces of flexion, extension, shortening, and torsion clearly distinguishes it from the coronary arteries.These mechanical forces are known to impart to the SFA cyclic circumferential strain and deformation, promoting cellular proliferation, chronic vessel injury, and perturbations in the expression of several genes hypothesized to accelerate atherosclerosis.In light of these realities, there has been a concerted effort to apply strategies and technologies to infrainguinal arteries that have served us well in treating coronary artery disease.Excepting a few notable bright spots, this approach has been woefully inadequate, with only modest treatment success of peripheral artery interventions becoming the accepted norm.The SFA is prone to de novo atherosclerosis and restenosis after peripheral artery intervention as a result of the unique proliferative biology linked to its particular biomechanics. 3 Early atherosclerotic lesions are more common in the adductor hiatus region of the SFA, and involvement of proximal and mid segments indicates more advanced disease.SFA deformations with knee and hip flexion can result in stent-vessel interaction and stent fracture that are hypothesized to provoke clinical sequelae.Stent fractures are more common in the proximal and mid SFA.Shortening of the SFA is greatest in the bottom third compared with the top two thirds of the vessel, and the artery undergoes significant deformation and buckling during hip and knee flexion that increases with age.The arc of curvature is greatest at the bottom portions of the artery and least in the middle portions, probably because the adductor canal provides more constraint proximal to the adductor hiatus.Recognition of these anatomic features may have important practical implications, ranging from improved device design and testing to ultimate development of subject-specific device therapies harmonious with each individual's femoropopliteal artery biomechanical environment.The more recent innovation of open-cell stent design for SFA stents has allowed greater axial, twisting, and bending flexibility with a lowering of stent fracture rates. Superficial Femoral Artery Is Not Left Anterior Descending Artery