Occlusion of neck remnant in experimental rat aneurysms after treatment with platinum- or polyglycolic-polylactic acid-coated coils.
BACKGROUND
Neck remnants and aneurysm recurrences are marked limitations of endovascular treatment of cerebral artery aneurysms. We compared the evolution of neck remnants of experimental arterial rat aneurysms after treatment with either platinum- or PGLA-coated coils.


METHODS
We created 20 standard-size aneurysms in the abdominal aortas of male Wistar rats. Aneurysms were embolized with either PGLA-coated coils or platinum coils, with care taken to leave a neck remnant. Neck remnant size and shape was closely monitored to detect progressive enlargement or occlusion. Using a 4.7 T MR scanner, we acquired high-resolution MR images 6 times during the 4-week follow-up. For quantitative measurements, we used a high-resolution 3D-TOF angiography sequence. Results were verified by endoscopy and histology.


RESULTS
Aneurysms treated with PGLA coils showed, on average, a 12.9% reduction of neck remnant size (P = .044) and significant disappearance of dog ears, the blood-filled spaces between coils and aneurysm wall. The aneurysms treated with platinum coils lacked these changes. In endoscopy, neointima was found to cover both PGLA and platinum coils but was more often incomplete or translucent in the platinum group. In histology, thrombus organization and inflammatory cell infiltration were higher with PGLA.


CONCLUSIONS
Use of PGLA-coated coils was followed by a moderate progressive reduction of the neck remnant size and a better angiographic outcome, seen as disappearance of dog ears during follow-up. The rat model proved to be suitable for comparison of different coil types.
Marjamaa
Johan
J
Neurosurgery Research Group, Biomedicum Helsinki, Finland. johan.marjamaa@hus.fi
Tulamo
Riikka
R
Frösen
Juhana
J
Abo-Ramadan
Usama
U
Hernesniemi
Juha A
JA
Niemelä
Mika R
MR
Kangasniemi
Marko
M
D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology / Q000601:surgery; D017544:Aortic Aneurysm, Abdominal / Q000473:pathology / Q000601:surgery; D004195:Disease Models, Animal; D004621:Embolization, Therapeutic / Q000295:instrumentation* / Q000379:methods*; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008297:Male; D010984:Platinum / Q000627:therapeutic use*; D011091:Polyesters / Q000627:therapeutic use*; D011182:Postoperative Care; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D019736:Prostheses and Implants; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D013927:Thrombosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D016896:Treatment Outcome; D017539:Tunica Intima / Q000473:pathology / Q000601:surgery
D011091:Polyesters; C507868:poly(glycolide-co-lactide-co-caprolactone); D010984:Platinum