Derivation of neointima in vascular grafts.
Vascular prostheses woven from absorbable lactide/glycolide copolymers are replaced by myofibroblast-laden tissue conduits lined by endothelium. When these prostheses are implanted in arteries of animal models, the absorption-replacement reactions are inhibited by Dacron. To determine whether these reactions resulted primarily from transanastomotic pannus ingrowth, prostheses (30 mm x 4 mm) were constructed of three 10-mm long segments with Dacron segments on both ends and a middle polyglactin 910 (PG910) segment. The prostheses were implanted in the aortas of 15 adult New Zealand White rabbits. Resultant prosthesis/tissue complexes were harvested in triplicate at 2 weeks and at 1, 2, 3, and 4 months after implantation. Explants were photographed and sectioned for light microscopy and for scanning and transmission electron microscopy, which showed 100% patency with no aneurysms or stenoses. Inner-capsule thickness in the PG910 segments increased only during the interval from 2 weeks to 2 months; this thickness was statistically greater than either Dacron segment at 1 and 2 months (p less than or equal to 0.004 and p less than or equal to 0.0001, respectively). Proximal and distal Dacron segments did not differ from each other in thickness. Inner capsules of PG910 segments at 1 month were composed predominantly of myofibroblasts, whereas inner capsules of Dacron segments were composed of fibrin coagulum beyond the initial 2 mm of endothelial pannus ingrowth. These data suggest that transanastomotic pannus ingrowth is not the primary source of cells replacing absorbable vascular prostheses.
Greisler
H P
HP
Department of Surgery, Loyola University School of Medicine, Maywood, Illinois.
Dennis
J W
JW
Endean
E D
ED
Ellinger
J
J
Buttle
K F
KF
Kim
D U
DU
D000042:Absorption; D000818:Animals; D001012:Aorta, Abdominal / Q000601:surgery; D001807:Blood Vessel Prosthesis; D004730:Endothelium, Vascular / Q000648:ultrastructure*; D005260:Female; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011093:Polyethylene Terephthalates; D011098:Polyglactin 910; D011817:Rabbits
D011093:Polyethylene Terephthalates; D011098:Polyglactin 910