Biocompatibility studies of the Anaconda stent-graft and observations of nitinol corrosion resistance.
OBJECTIVE
To validate the deployment, in vivo performance, biostability, and healing capacity of the Anaconda self-expanding endoprosthesis in a canine aortic aneurysm model.


METHODS
Aneurysms were surgically created in 12 dogs by sewing a woven polyester patch onto the anterior side of the thoracic or abdominal aorta. Anaconda prostheses were implanted transfemorally for prescheduled periods (1 or 3 months). Aneurysm exclusion and stent-graft patency were monitored angiographically. Healing was assessed with histological analysis and scanning electron microscopy (SEM). Textile analysis determined the physical and chemical stability of the woven polyester material, while the biostability of the nitinol wires was evaluated with SEM and spectroscopy.


RESULTS
All prostheses were intact at explantation. After 1 month, endothelial-like cells were migrating in a discontinuous manner both proximally and distally over the internal collagenous pannus at the device-host boundary. After 3 months, endothelialization had reached the midsections of the devices, with a thicker collagenous internal capsule. Patches of endothelial-like cells were sharing the luminal surface with thrombotic deposits. However, the wall of the device at the level of the aneurysm was generally poorly healed, with multiple thrombi scattered irregularly over the luminal surface. The polyester fabric was intact except for some filaments that were ruptured adjacent to the sutures and some abrasion caused by the nitinol wires. No evidence of corrosion was found on the nitinol stents.


CONCLUSIONS
This Anaconda stent-graft has demonstrated its ability to exclude arterial aneurysms. The device used in this study was an experimental prototype, and the manufacturer has incorporated new immobilization features into the model for clinical use. The constituent materials appear to be suitable in terms of biocompatibility, biofunctionality, and short-term durability.
Guidoin
Robert
R
Department of Surgery, Laval University, and Quebec Biomaterials Institute, St-François d'Assise Hospital, CHUQ, Quebec, QC, Canada. robertguidoin@hotmail.com
Douville
Yvan
Y
Baslé
Michel F
MF
King
Martin
M
Marinov
Georgi R
GR
Traoré
Amidou
A
Zhang
Ze
Z
Guillemot
Fabien
F
Dionne
Guy
G
Sumanasinghe
Ruwan
R
Legrand
André-Pierre
AP
Guidoin
Marie-France
MF
Porté-Durrieu
Marie-Christine
MC
Baquey
Charles
C
D000497:Alloys / Q000737:chemistry / Q000627:therapeutic use*; D017130:Angioplasty; D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000473:pathology / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation; D003343:Corrosion; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D008297:Male; D008422:Materials Testing; D011091:Polyesters / Q000627:therapeutic use; D011474:Prosthesis Design; D015607:Stents; D014945:Wound Healing
D000497:Alloys; D011091:Polyesters; C013616:nitinol