Detrimental effects of mechanical stretch on smooth muscle function in saphenous veins

• Published in: Journal of vascular surgery 2011-02, Vol.53 (2), p.454-460
• Main Authors: Hocking, Kyle M., BE, Brophy, Colleen, MD, Rizvi, Syed Z., MD, Komalavilas, Padmini, PhD, Eagle, Susan, MD, Leacche, Marzia, MD, Balaguer, Jorge M., MD, Cheung-Flynn, Joyce, PhD
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; General and cellular metabolism. Vitamins; Humans; In Vitro Techniques; Mechanotransduction, Cellular - drug effects; Medical sciences; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - metabolism; Muscle, Smooth, Vascular - surgery; Pharmacology. Drug treatments; Pressoreceptors - drug effects; Pressoreceptors - metabolism; Pressure; Saphenous Vein - metabolism; Saphenous Vein - surgery; Surgery; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Swine; Tissue and Organ Harvesting; Tissue Survival; Vascular surgery: aorta, extremities, vena cava. Surgery of the lymphatic vessels; Vasoconstriction - drug effects; Vasoconstrictor Agents - pharmacology
• ISSN: 0741-5214; 1097-6809
• DOI: 10.1016/j.jvs.2010.09.010

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, 105 N/m2 ) 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 × 105 N/m2 to 0.1192 ± 0.02776 × 105 N/m2 ). 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.