title: Passive biaxial mechanical properties and in vivo axial pre-stretch of the diseased human femoropopliteal and tibial arteries.
abstract: Surgical and interventional therapies for atherosclerotic lesions of the infrainguinal arteries are notorious for high rates of failure. Frequently, this leads to expensive reinterventions, return of disabling symptoms or limb loss. Interaction between the artery and repair material likely plays an important role in reconstruction failure, but data describing the mechanical properties and functional characteristics of human femoropopliteal and tibial arteries are currently not available. Diseased superficial femoral (SFA, n = 10), popliteal (PA, n = 8) and tibial arteries (TA, n = 3) from 10 patients with critical limb ischemia were tested to determine passive mechanical properties using planar biaxial extension. All specimens exhibited large nonlinear deformations and anisotropy. Under equibiaxial loading, all arteries were stiffer in the circumferential direction than in the longitudinal direction. Anisotropy and longitudinal compliance decreased distally, but circumferential compliance increased, possibly to maintain a homeostatic multiaxial stress state. Constitutive parameters for a four-fiber family invariant-based model were determined for all tissues to calculate in vivo axial pre-stretch that allows the artery to function in the most energy efficient manner while also preventing buckling during extremity flexion. Calculated axial pre-stretch was found to decrease with age, disease severity and more distal arterial location. Histological analysis of the femoropopliteal artery demonstrated a distinct sub-adventitial layer of longitudinal elastin fibers that appeared thicker in healthier arteries. The femoropopliteal artery characteristics and properties determined in this study may assist in devising better diagnostic and treatment modalities for patients with peripheral arterial disease.
authors.affiliation: Department of Surgery, University of Nebraska Medical Center, Omaha, NE, USA. Electronic address: Alexey.Kamenskiy@unmc.edu.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Kamenskiy
authors.affiliation: Department of Surgery and VA Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA; Department of Surgery, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Iraklis I
authors.initials: II
authors.lastname: Pipinos
authors.affiliation: Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA.
authors.forename: Yuris A
authors.initials: YA
authors.lastname: Dzenis
authors.affiliation: Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Carol S
authors.initials: CS
authors.lastname: Lomneth
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Syed A Jaffar
authors.initials: SA
authors.lastname: Kazmi
authors.affiliation: Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA.
authors.forename: Nicholas Y
authors.initials: NY
authors.lastname: Phillips
authors.affiliation: Department of Surgery, University of Nebraska Medical Center, Omaha, NE, USA. Electronic address: JMacTaggart@unmc.edu.
authors.forename: Jason N
authors.initials: JN
authors.lastname: MacTaggart
mesh_terms: D000368:Aged; D016880:Anisotropy; D001696:Biomechanical Phenomena; D003710:Demography; D005263:Femoral Artery / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D011150:Popliteal Artery / Q000473:pathology / Q000503:physiopathology*; D013314:Stress, Mechanical; D016909:Tibial Arteries / Q000473:pathology / Q000503:physiopathology*
keywords: Biaxial mechanical properties; Constitutive modeling; Femoropopliteal artery; In vivo axial pre-stretch; Tibial artery