In vivo assessment of calcium alginate gel for endovascular embolization of a cerebral arteriovenous malformation model using the Swine rete mirabile.
OBJECTIVE
We sought to assess the stability of calcium alginate as an embolic agent in an animal model of a cerebral arteriovenous malformation (AVM). Swine cerebral AVM models were used to test the injectability, radiographic visualization, mechanical stability, and biocompatibility of calcium alginate as an occlusive agent.


METHODS
The swine cerebral AVM model included a carotid-to-jugular anastomosis to increase flow to the rete mirabile (RM), thereby simulating the pressure gradient and shunted blood flow of an AVM. Alginate and the reactive component, calcium chloride, were injected from double-lumen microcatheters to form a complete RM occlusion in the "acute swine" AVM model and a partial occlusion in a "survival swine" model.


RESULTS
Angiographic and histological results verified complete occlusion of the left RM in acute animals when alginate was injected in stages. Partial RM occlusion in the survival animals blocked blood flow to the inferior portion of the RM but left flow open to the superior portion of the RM and the circle of Willis. One-week survival results showed that the alginate remained a stable occlusive material. Histological results showed a minor bioactive response and encapsulation of the alginate polymer, thereby increasing the stability and effective occlusion of the embolization material.


CONCLUSIONS
Calcium alginate proved to be an effective endovascular occlusion material that blocked blood flow to the swine RM. The swine AVM models provided assessment of alginate injectability and effective occlusion and provided initial in vivo characteristics of alginate stability and biocompatibility.
Bioengineering Department, Arizona State University, Tempe, USA. beckert@umich.edu
Timothy A
TA
Becker
Daryl R
DR
Kipke
Mark C
MC
Preul
William D
WD
Bichard
Cameron G
CG
McDougall
D000464:Alginates / Q000627:therapeutic use*; D000818:Animals; D002533:Cerebral Angiography; D004195:Disease Models, Animal; D004621:Embolization, Therapeutic; D005782:Gels; D020723:Glucuronic Acid; D006490:Hemostatics / Q000627:therapeutic use*; D006603:Hexuronic Acids; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D016019:Survival Analysis; D013552:Swine
D000464:Alginates; D005782:Gels; D006490:Hemostatics; D006603:Hexuronic Acids; D020723:Glucuronic Acid