title: Detrimental effects of mechanical stretch on smooth muscle function in saphenous veins.
abstract: OBJECTIVE
  This study evaluated the smooth muscle functional response and viability of human saphenous vein (HSV) grafts after harvest and explored the effect of mechanical stretch on contractile responses of porcine saphenous vein (PSV).
  
  
  METHODS
  The contractile responses (stress, 10(5) N/m(2)) of deidentified, remnant HSV grafts to depolarizing potassium chloride and the agonist norepinephrine were measured in a muscle organ bath. Cellular viability was evaluated using a methyl thiazole tetrazolium (MTT) assay. A PSV model was used to evaluate the effect of radial, longitudinal, and angular stretch on smooth muscle contractile responses.
  
  
  RESULTS
  Contractile responses varied greatly in HSV harvested for autologous vascular and coronary bypass procedures (0.04198 ± 0.008128 × 10(5) N/m(2) to 0.1192 ± 0.02776 × 10(5) N/m(2)). Contractility of the HSV correlated with the cellular viability of the grafts. In the PSV model, manual radial distension of ≥ 300 mm Hg had no impact on the smooth muscle responses of PSV to potassium chloride. Longitudinal and angular stretch significantly decreased the contractile function of PSV by 33.16% and 15.26%, respectively (P < .03).
  
  
  CONCLUSIONS
  There is considerable variability in HSV harvested for use as an autologous conduit. Longitudinal and angular stretching during surgical harvest impairs contractile responsiveness of the smooth muscle in saphenous vein. Avoiding stretch-induced injuries to the conduits during harvest and preparation for implantation may reduce adverse biologic responses in the graft (eg, intimal hyperplasia) and improve patency of autologous vein graft bypasses.
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tenn 37232-2735, USA.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Hocking
authors.forename: Colleen
authors.initials: C
authors.lastname: Brophy
authors.forename: Syed Z
authors.initials: SZ
authors.lastname: Rizvi
authors.forename: Padmini
authors.initials: P
authors.lastname: Komalavilas
authors.forename: Susan
authors.initials: S
authors.lastname: Eagle
authors.forename: Marzia
authors.initials: M
authors.lastname: Leacche
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Balaguer
authors.forename: Joyce
authors.initials: J
authors.lastname: Cheung-Flynn
mesh_terms: D000818:Animals; D006801:Humans; D066298:In Vitro Techniques; D040542:Mechanotransduction, Cellular / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000601:surgery; D011311:Pressoreceptors / Q000187:drug effects / Q000378:metabolism*; D011312:Pressure; D012501:Saphenous Vein / Q000378:metabolism / Q000601:surgery; D013552:Swine; D014022:Tissue Survival; D020858:Tissue and Organ Harvesting; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents