Long-term histological and scanning electron microscopy results of endovascular and operative treatments of experimentally induced aneurysms in the rabbit.
OBJECTIVE
Treatment strategies of cerebral aneurysms include surgical clipping and endovascular therapies. To determine the long-term results of these therapeutic strategies, the vessel wall reaction close to the former aneurysm was studied according to the assumption that an intact endothelial layer over the former aneurysm neck constitutes complete vessel wall reconstruction and stable aneurysm obliteration.


METHODS
Aneurysms were created in 40 rabbits by intraluminal elastase incubation of the common carotid artery. Five animals each were assigned to the following groups: untreated, porous stents, polyurethane covered stentgrafts, porous stents with subsequent coiling. Ten animals were treated with coils alone, 10 with clips. After 6 months, angiography, histology, and scanning electron microscopy was performed.


RESULTS
Porous stents did not obliterate the aneurysm, whereas stentgrafts did; in-stent stenosis of up to 60% was present because of neointimal multilayer proliferation. After coiling, the aneurysm dome was occluded with fibrinous and collagenous material, whereas the aneurysm neck was not covered by an endothelial lining. Coil loops lay bare within the vessel, with fresh thrombus material on their surface. After clipping, a thin layer of endothelial lining bridging the two attached vessel walls was present, thereby completely obliterating the aneurysm and reconstructing the vessel wall.


CONCLUSIONS
This study demonstrates complete and stable aneurysm obliteration with vessel wall reconstruction after clipping, a sufficient obliteration of the aneurysm dome using endovascular techniques, but a failed healing response of the aneurysm neck that might correlate to its associated higher risk of rebleed. Whether or not this is counterbalanced by the better immediate outcome after endovascular treatment remains a matter of debate.
Krings
Timo
T
Department of Neuroradiology,University Hospital, University of Technology, Aachen, Germany. tkrings@izkf.rwth-aachen.de
Busch
Claudia
C
Sellhaus
Bernd
B
Drexler
Angela Y
AY
Bovi
Manfred
M
Hermanns-Sachweh
Benita
B
Scherer
Kira
K
Gilsbach
Joachim M
JM
Thron
Armin
A
Hans
Franz J
FJ
D000818:Animals; D001807:Blood Vessel Prosthesis; D002340:Carotid Artery Diseases / Q000139:chemically induced / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy*; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000473:pathology*; D002533:Cerebral Angiography; D003251:Constriction, Pathologic / Q000209:etiology; D004621:Embolization, Therapeutic / Q000009:adverse effects / Q000295:instrumentation; D004730:Endothelium, Vascular / Q000473:pathology; D002532:Intracranial Aneurysm / Q000139:chemically induced / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy*; D008855:Microscopy, Electron, Scanning; D019635:Neurosurgical Procedures; D010196:Pancreatic Elastase; D011184:Postoperative Period; D011817:Rabbits; D015607:Stents / Q000009:adverse effects; D013927:Thrombosis / Q000209:etiology; D013997:Time Factors; D014945:Wound Healing
D010196:Pancreatic Elastase