Developing an Experimental Aneurysm Model in a Rabbit Using an Elastase-Treated Vessel Pouch

Begin with an anesthetized rabbit with surgically exposed carotid arteries or CCAs supported by a blue pad for clear visualization.

Tie off the right CCA with sutures and clamp it distally to restrict blood flow.

Cut the section of the right CCA containing the tight knot to create a vessel pouch and clean it in heparinized saline to remove soft tissue.

Treat the pouch with a buffer containing elastase to degrade elastin fibers, weakening the vessel.

Support the left CCA and clip it to restrict blood flow.

Remove the attached soft tissues and pierce the left CCA to release trapped blood. 

Inject saline containing heparin to prevent blood clotting. 

Suture the cut right CCA to the left CCA. Later, ligate the elastase-treated pouch.

Now, remove all clamps to restore blood flow and suture the incision.

Blood flow in the artificial carotid bifurcation induces stress on the weakened vessel pouch walls, causing it to bulge and form an aneurysm. 

After tightening the 6-0 ligature, use a temporary vessel clip to clamp the right common carotid artery as far distally as possible to avoid endothelial damage to create a long vessel segment for irrigation to prevent thrombogenesis. To harvest the pouch, cut the distal vessel to the 4-0 non-absorbable ligature.

Then cut the vessel distal to the 6-0 non-absorbable ligature. Meticulously clean the arterial pouch of all soft tissue and use a vessel clip to measure the length, width, and depth of the pouch. If a pouch degradation is needed, pre-incubate the cleaned pouch with 100 units of porcine elastase dissolved in 5 milliliters of Tris buffer at room temperature for 20 minutes.

For further preparation of the common carotid artery, place two micro swabs directly beneath the left common carotid artery to allow the vessel to be moved superficially. And place an additional micro swab with a blue padding under the left artery at the distal third for better visualization of the artery. Change sides to access the left side of the animal, and use microscissors and forceps to make a 2-millimeter fishmouth incision on the proximal side of the right common carotid artery.

Use a second temporary vessel clip to clamp the left distal common carotid artery, and clamp the proximal left common carotid artery with two additional temporary vessel clips. When all of the clamps have been placed, liberate the distal third of the left common carotid artery completely from the soft tissue and perform an arteriotomy.

Now flush the recipient vessel with heparinized saline and liberate the complex from adventitia. Then suture the right common carotid artery to the left common carotid artery. Transfer the arterial pouch from the heparinized saline solution into the surgical field where the bifurcation is planned.

While keeping all of the aspects of the vessel complex hydrated with a continuous saline irrigation, suture the pouch to the vessel and then remove all of the temporary vascular clamps in stepwise manner. When all of the clamps have been removed, then close the operative situs according to standard protocols.