title: Post-implant evaluation of the anastomotic mechanical and geometrical coupling between human native arteries and arterial cryografts implanted in lower-limb: mechanical, histological and ultraestructural studies of implanted cryografts.
abstract: BACKGROUND
  There is an urgent need of vascular substitutes (VS) to be used in lower limb revascularization procedures when autologous veins are not available and synthetic prosthesis are contraindicated. Since the mechanical differences with respect to native vessels are determinants of the VS failure, the substitutes should have mechanical properties similar to those of the recipient vessels. The use of cryopreserved arteries (cryografts) could overcome limitations of available VS. These work aims were to characterize (a) native vessels/implanted cryografts mechanical and geometrical coupling, (b) cryografts capability to ensure mismatch levels lesser than those expected for expanded polytetrafluoroethylene (ePTFE), (c) cryografts functional properties considering their histological and ultra-structural characteristics.
  
  
  METHODS
  Instantaneous pressure (mechano-transducers) and diameter (B-mode echography) were obtained in implanted femoro-popliteal, ileo-femoro-popliteal and axilo-humeral cryografts (n=8), in femoral arteries from recipients (n=8), recipient-like (n=15) and multiorgan donors-like (n=15) subjects, and in ePTFE segments (n=10). Calculus: (a) Mechanical parameters: elastic modulus, arterial compliance, distensibility and characteristic impedance; (b) Arterial remodeling: diameter, wall thickness, cross-sectional area and wall-to-lumen ratio; (c) Native vessels/VS coupling. Histological and structural analysis were done in explanted femoro-popliteal and axilo-humeral cryografts (n=7).
  
  
  RESULTS
  Post-implant the cryografts remodeled. Their stiffness increased and the conduit function diminished. Remodeling resulted in an improvement in native vessels/cryograft coupling, which was always better than native vessels/ePTFE coupling.
  
  
  CONCLUSIONS
  Post-implant cryograft remodeling improved native vessels/cryografts coupling. Cryografts would have mechanical and geometrical advantages over ePTFE. Anastomotic cryograft remodeling differed from that expected only due to haemodynamic factors. The structural properties of the remodeled cryografts contribute to explain their functional characteristics.
authors: Physiology Department, School of Medicine, CUiiDARTE, Republic University, Montevideo, Uruguay. dbia@fmed.edu.uy
authors: Daniel
authors: D
authors: Bia
authors: Yanina
authors: Y
authors: Zócalo
authors: Ricardo L
authors: RL
authors: Armentano
authors: Héctor
authors: H
authors: Pérez-Cámpos
authors: Juan
authors: J
authors: Fernández-Pin
authors: Ana
authors: A
authors: Panuncio
authors: María
authors: M
authors: Saldías
authors: Ana
authors: A
authors: Mariño
authors: Inés
authors: I
authors: Alvarez
mesh_terms: D000368:Aged; D000714:Anastomosis, Surgical / Q000379:methods; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D015925:Cryopreservation; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology / Q000601:surgery / Q000637:transplantation*; D006801:Humans; D035002:Lower Extremity / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged