1. Creation of terminal aneurysms with realistic, low resistance arterial wave forms in rabbits
Yonghong Ding, Ehteshami Rad, Arash, Daying Dai, Ramanathan Kadirvel, Debra A. Lewis, and David F. Kallmes
Neuroradiology Research Laboratory, Department of Radiology, Mayo Clinic, Rochester, MN. USA

2. Background
Experimental aneurysm is critical for testing of endovascular devices and study for hemodynamic mechanism related to aneurysm
Different with side wall and bifurcation aneurysms, terminal aneurysm represent another specific shape of intracranial aneurysm.

3. Background
Current models created in extracranial vessels have HIGH resistance, LOW diastolic flow patterns, since they serve muscular tissues
Human, intracranial flow is LOW resistance, HIGH diastolic flow, unlike current models

4. Background Downstream AV fistulae can be used to modulate flow
Increased flow in diastole from these AV fistulae can create LOW resistance, HIGH distolic flow patterns, even in extracranial vessels

5. Purpose
To explore the possibility to create terminal aneurysm with arterio-venous fistula in rabbits .

6. Materials and Methods
Terminal aneurysms were created in right common carotid artery (RCCA) in 3 New Zealand White rabbits,
Arterial side to end anastomosis of RCCA and left common carotid artery (LCCA), then a venou pouch was sewn onto RCCA at the above anastomosis site to create terminal aneurysm.

7. Materials and Methods
RCCA-right jugular AVF was created at the proximal side of the anastomosis, followed by permenant ligation of RCCA proximal to AVF.

8. Materials and Methods
Intravenous digital subtraction angiography (IVDSA) was performed immediately and 3 weeks after the whole surgical procedure to evaluate the patency of aneurysm and fistula.

9. Results IVDSA immediately after creation
All the 3 aneurysms and AVF were shown as patent from IVDSA images immediately after creation

10. Results IVDSA 3 weeks after creation
Both aneurysm (arrow) and AVF (block arrow) were patent in two (67%) rabbits (see following figure).
In another (33%) rabbit, the aneurysm was patent but the fistula was occluded.

12. Human ICA Rabbit, no AVF Rabbit, AVF

13. Discussion
Terminal aneurysm model has been was made in canine to test endovascular devices and evaluate hemodynamic situation in aneurysms.
For our knowledge, no similar study has been performed in rabbits.

14. Discussion
In this study, all the 3 terminal aneurysms remained patent 3 weeks after creation, thus creation of terminal aneurysm in rabbits is possible.

15. Discussion
Besides mimicking the shape of terminal aneurysm in patients, we also tried to increase blood flow through the vascular trunk by creating an arterio-venous fistula (AVF) in the parent artery near the aneurysm.

16. Conclusion
Creation of surgical terminal aneurysm with arterio-venous fistula is possible in rabbits.

17. Thank you