Utilization of shape memory in external vein-graft meshes allows extreme diameter constriction for suppressing intimal hyperplasia: A non-human primate study

• Published in: Journal of vascular surgery 2009-06, Vol.49 (6), p.1532-1542
• Main Authors: Zilla, Peter, MD, PhD, Wolf, Michael, BSc, Rafiee, Nasser, BSc, Moodley, Loven, MBChB, Bezuidenhout, Deon, PhD, Black, Melanie, DipMedTech, Human, Paul, PhD, Franz, Thomas, PhD
• Format: Article
• Language: English
• Subjects: Alloys; Anastomosis, Surgical; Animals; Biological and medical sciences; Constriction; Endothelial Cells - pathology; Equipment Design; Femoral Artery - pathology; Femoral Artery - physiopathology; Femoral Artery - surgery; Femoral Vein - pathology; Femoral Vein - physiopathology; Femoral Vein - transplantation; Fibrin Tissue Adhesive; Hyperplasia; Medical sciences; Models, Animal; Neurosurgery; Papio ursinus; Regional Blood Flow; Skull, brain, vascular surgery; Surgery; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgical Mesh; Time Factors; Tissue Adhesives; Tunica Intima - pathology; Tunica Media - pathology; Vascular Patency; Vascular surgery: aorta, extremities, vena cava. Surgery of the lymphatic vessels; Vascular Surgical Procedures - adverse effects; Vascular Surgical Procedures - instrumentation; Vascular Surgical Procedures - methods
• ISSN: 0741-5214; 1097-6809
• DOI: 10.1016/j.jvs.2009.01.068

Objective Constrictive external Nitinol meshes have been shown to suppress neointimal tissue formation and preserve endothelial integrity in vein grafts. As this mitigating effect increased with the degree of constriction, we investigated whether extreme constriction was possible without leading to detrimental luminal encroachment. Methods A senescent non-human primate model (Chacma baboons/bilateral femoral interposition grafts) mimicking the clinical size-mismatch between vein grafts and run-off arteries was used. Control grafts were either untreated (group 1) or spray-coated with fibrin glue (group 2). Nitinol meshes constricting the lumen by ≤80% (group 3) were compared with longitudinally pleated meshes of identical circumference that constricted the lumen by >90% (group 4). Anastomotic size mismatch at implantation was expressed as quotient of cross-sectional area of run-off artery to vein graft (Q C ). Results At 6 months, all vein grafts without mesh support showed thick eccentric layers of neointimal tissue (group 1: 348 ± 130 μm [Q C median at implant 0.19]; group 2: 318 ± 142 μm [Q C median at implant 0.17]). Fibrin glue-spraying had no effect. In contrast, neointimal tissue was absent in all mesh-supported grafts ( P < .007 in all cases) both at 6 weeks/6 months (group 3: 7.5 ± 8.8 μm and 2.5 ± 4.4 μm [Q C median at implant 1.47]; group 4: 1.3 ± 0.6 μm and 3.8 ± 5.6 μm [Q C median at implant 3.09]). Except for mild tissue buckling (fold height