0. The Nexeon Bistable Nitinol Stent Family
William A. Gray MD
Director of Endovascular Services
Associate Professor of Clinical Medicine

1. William A. Gray, MD DISCLOSURES Consulting Fees
AccessClosure, Inc., CoAptus, Inc., Mercator MedSystems, Inc., Ovalis, Inc., Paragon Medical, Inc., Pathway Medical Technologies, Inc., Sage Medical, Inc.
Grants/Contracted Research
Atritech, Inc., Cordis, a Johnson & Johnson company, CREST/ National Institutes of Health, W.L. Gore & Associates, Inc.
Ownership Interest (Stocks, Stock Options or Other Ownership Interest)
AccessClosure, Inc., CoAptus, Inc., Ovalis, Inc., Paragon Medical, Inc., Pathway Medical Technologies, Inc., Sage Medical, Inc.

2. Stent technology: the advantages of both constructions is possible
Today
1990s
1980s
Balloon Expandable Stents
(BES)
Self Expanding Stents
(SES)
BES with SES properties
Metal Stent Design Evolution
BES: Accurate single step but deformation an issue
for peripheral applications
SES: Crush resistant and better wall apposition but
less accurate and multiple steps required
Citation stent
CAUTION – Device not approved for sale or distribution

3. Finite element analysis (FEA) of current tube-cut nitinol stents
CAUTION – Device not approved for sale or distribution

4. Inversion Point™ Stent Technology achieves bistability in nitinol
FEA of 2 Citation stent cells crimping
CAUTION – Device not approved for sale or distribution

5. Nitinol bistability allows new considerations in stenting
Balloon Expandable Non-Crushable Stent
The accuracy of balloon placement
Direct stenting with nitinol
1-2 less steps per stent
Less radiation exposure
Cost savings (less balloon use)
Value of bistable stenting is in the system potential to match the “ease of use” value of rapid exchange
CAUTION – Device not approved for sale or distribution

6. Bistable nitinol conforms to vessel contours
OCT of Citation stent in porcine iliac
(accommodation of bladder compression between 11:00 and 2:00)
CAUTION – Device not approved for sale or distribution

7. Comparison of stent classes
Conventional SS or CoCr Stent
Conventional NiTi Stent
Bistable NiTi Stent
Non-deformable No
Yes
Conformability 

Accuracy
Direct stenting
Delivery system flexibility
Procedure steps
1 to 2
2 to 3
CAUTION – Device not approved for sale or distribution

8. Journal of Vascular Surgery 2008; 48:435-440
What about vessel length and conformational changes? SFA and popliteal foreshortening
Two cadaver studies evaluated the % decrease in stent length with axial load.
Results showed reduction of stent length by 3% to 25%.
Measurement of stent shortening and bending was tested in cadaveric femoropopliteal arteries. A, A radiograph shows the stent in a leg in neutral position. The bending angle (°) and stent length (L) are labeled. B, A radiograph shows the stent at knee/hip flexion 90°/90°. Axial compression was determined by subtraction of the measured data at flexed position from the data at neutral position and deflection angle by subtraction of the data at neutral position from the data at flexed position.
Journal of Vascular Surgery 2008; 48:

9. Consequences of a stent with limited axial compression ability during knee bend
Stent distal edge
Stent distal edge

10. SFA nitinol stent fracture and restenosis due to axial compression and stent yield or “hinge points”

12. TRIAD™ stent system: A next-generation SFA stent
Nitinol
Bistability
Controlled Ring Segmentation
CAUTION – Device not approved for sale or distribution

13. Controlled Ring Segmentation Design
Design goals
Provide for longitudinal (axial) and torsional flexibility required by SFAs
Lessen wall shear stress interaction with artery
Maintain value of bistability
Accuracy, less steps, cost savings, less radiation exposure, deliverability
CAUTION – Device not approved for sale or distribution

14. TRIAD™ Pre-Clinical Animal Study

15. Bistable Stent Family  Accuracy Less Steps Delivery Cost Savings
Other
Iliacs 
SFAs
Controlled Ring Segmentation for axial conformability
Popileteal
Carotids
Spot stenting of ICA
.014” BDC delivery to reduce sheath prolapse risk
Venous
Lower profile, large NiTi stents
Neuro
Lower profile, microcatheter compatibility
Grafts
Percutaneous option
CAUTION – Device not approved for sale or distribution

16. Maturation of the Technology: Today
Cobalt alloys (low profile and less elastic recoil):
Low-profile coronary stent with a prohealing coating has completed EU safety/feasibility trial
Medium and large peripheral stents in pre-clinical assessment
Shape memory alloys (balloon expandable crush resistant):
Iliac stent completing pre-clinical studies
CAUTION – Device not approved for sale or distribution

17. Maturation of the Technology: Implications for Tomorrow
SFA Segmented: Initiated pre-clinical testing
SFA Helical: In design phase
Future: Carotids, stent grafts, low profile valve rings…
CAUTION – Device not approved for sale or distribution

18. Conclusion
Bistable stenting offers a new class of stents that promises to combine the benefits of today’s BE and SE stents
Additionally, bistability allows for clinical and engineering applications not previously possible
Accurate spot stenting
Direct stenting of NiTi
Segmented stent design
CAUTION – Device not approved for sale or distribution