The Merci ® Retrieval System

1. The Merci® Retrieval System Presentation prepared by Concentric Medical, September 2006 Not intended for distribution within the United States or Canada.

2. The Merci® System • Simple, elegant solution for ischemic stroke • Retriever’s unique corkscrew design and Nitinol material enables the device to: • straighten inside the catheter, then • return to its original shape when deployed • This allows device to be delivered distal to thrombus using standard catheterization techniques • Merci Retrieval System • Merci® Retriever • Merci® Microcatheter • Merci® Balloon Guide Catheter

3. Merci® Retriever Indications • The only thrombectomy device specifically approved for the removal of thrombus in patients with ischemic stroke. • FDA cleared (August 2004) and approved in the EU via CE Mark. • The Merci Retriever has been used in > 3,000 patients and 200 centers since 2004. • The Merci Retriever is intended to restore blood flow in patients experiencing ischemic stroke.  Patients who are ineligible for intravenous (IV t-PA) or who fail IV t-PA therapy are candidates for treatment. • The Merci Retriever is also indicated for use in the retrieval of foreign bodies in the neuro, peripheral and coronary vasculature.

4. Mechanical RevascularizationFastest Way to Restore Flow • Merci® Retriever is advanced (A) • through Microcatheter • distal to thrombus • Retriever is deployed (B) • Retriever engages the thrombus • Microcatheter proximal to Retriever • Captured thrombus is slowly removed (C) • Balloon Guide Catheter provides proximal flow control • Retriever and Microcatheter removed through Balloon Guide Catheter A B C

5. MERCI Animation

6. Merci Provides Options • Location: Large Vessel Occlusion • NIH Stroke Scale ≥ 12 is 91% predictive of large vessel occlusions • Options: • Failed IV lytic cases • Ineligible for lytic: • On oral anticoagulants • Recent surgery • Recent stroke • Symptom onset > 3 hours • Time: Opening the Treatment Window

7. Opening the Time Window † Not FDA approved. Concentric does not endorse off-label use ‡ The MERCI and Multi MERCI trials evaluated patients up to 8 hours

8. Clinical Results • MERCI clinical trial provided basis for FDA clearance • 141 patients treated in 25 U.S. stroke centers

9. Revascularization Correlates with Good Outcome (90-Day mRS ≤ 2) 45% 35/78 p <0.0001* 2% 1/52 MERCI Post Procedure Status Only one of the 52 MERCI non-revascularized patients had a good outcome * P-values calculated as post-hoc analysis

10. Revascularization Correlates with Good Outcome in All Time Windows* N=16 N=12 N=42 N=31 N=10 N=5 0-3 hrs 0-2 mRS difference p=0.0514 3-6 hrs 0-2 mRS difference p<0.0001 6+ hrs† 0-2 mRS difference p=0.4936 †The MERCI trial evaluated patients up to 8 hours *Anterior circulation only. P-values calculated as post-hoc analysis Duckwiler, ASITN Course & Workshops, August 2005

11. Typical Clots Retrieved 62 year-old Male ICA occlusion History of atrial fibrillation 82 year-old Female MCA occlusion History of atrial fibrillation Failed IV lytic 32 year-old Male Basilar occlusion

12. Not So Typical Clot Retrieved

13. Multi MERCI (Part I) Trial • 111 patients with angiographically proven large vessel occlusive strokes were treated with the Merci® Retrieval System in 14 stroke centers • Same study design as MERCI except: • Included failed IV lytic (t-PA) patients • Included next generation Merci Retriever L5 • Demographics:

14. Multi MERCI (Part I) Trial

15. Multi MERCI (Part I) Revascularization by Vessel 80% 69% 69% 67%

16. Multi MERCI (Part I) Revascularization Correlates withGood Outcome (90-Day mRS ≤ 2) 47.3% p<0.0001* 34.3% 35/74 5.9% 37/108 2/34 Post Procedure * P-values calculated as post-hoc analysis

17. Conclusion Merci provides options: • Location • Large Vessel Occlusion • Options • Failed IV lytic cases • Ineligible for lytic • Time: Opening the Treatment Window Revascularization is the strongest predictor of good outcome. The Merci procedure can dramatically improve patient outcome.