1. The Mechanical Bioprosthesis: Does Valve Motion Predict Thrombogenicity ?
Lawrence Scotten1
David Walker1
Peter Harbott2
Jurgen de Hart3
Robert Perrault4
Damien Coisne4
Ernie Lane2
Didier Lapeyre2
ViVitro Systems Inc.,
Victoria, Canada
Lapeyre-Triflo Industries LLC,
Atlanta, USA
Technische Universiteit
Eindhoven, the Netherlands
Aerodynamics Institute, CNRS,
Poitiers, France

2. Valve design and motion are major determinants of flow structure
Background:
Valve design and motion are major determinants of flow structure
Un-natural flow structure can cause trauma to blood cell membranes
KEY discovery recently reported that traumatized blood cell membranes
release glycoprotein tissue-factor which initiates blood coagulation.

3. may not need anti-coagulation
Background:
*Prior study of valve motion:
(aortic & mitral)
4 Biological vs. 6 Mechanical
Open more rapidly
Close more gently
Exhibit NO rebound
Unaffected by gravity
Stable cycle to cycle behavior
*Conclusion:
Newer mechanical valve designs that mimic biological valve motion
may not need anti-coagulation
CONCLUSION:
-A new valve testing technique has been demonstrated which eases the analysis of valve motion
-and shows that valves demonstrate unique kinematics
-Compared to Mechanical valves -BIOLOGICAL VALVES
Open more rapidly
Close more gently
Exhibit NO rebound
Unaffected by gravity
Have stable cycle to cycle behavior
*New laboratory technique measures projected dynamic area of prosthetic heart valves. J Heart Valve Dis 2004;13:120-33

4. All valves were size 25 mm TAD
Aortic Valves Tested:
Methods
New three leaflet mechanical valve
Lapeyre -Triflo
All valves were size 25 mm TAD
Widely used clinical valves
Carpentier-Edwards PerimountTM
St. Jude Medical RegentTM

5. Laboratory technique reveals valve motion
Test conditions:
Laboratory technique reveals valve motion
Leonardo A.D. 2005
Area Detection System
Methods
Light sensor
(Response to 1 MHz)
TEST CONDITIONS:
Aortic position
Rate 70 BPM
Cardiac output
5 L/min
Systemic pressures 120/80 mmHg
10 consecutive cycles recorded
Light source

6. Valve motion was revealed by open area
Methods
Valve motion was revealed by open area

7. Methods

8. Low thrombogenicity with tissue valve motion
Results
Carpentier-Edwards
PerimountTM
Low thrombogenicity with tissue valve motion
VALVE MOTION (Area)
FLOW
cm2
OPEN PHASE: Valve motion responds well to slowly decreasing flow
ml/s 3
600
OPEN
RAPID opening
MAX.
NOTE: Valve reaches maximum opening…
GENTLE closing
32 ms AHEAD of flow max.
OPENING: Valve opens rapidly providing no obstacle to the accelerating flow
CLOSING: Valve motion responds quickly to decreasing flow
FINAL CLOSURE: Low leaflet closing velocity, small regurgitation, no rebound
> ¾ closed at zero flow
24% OPEN
CLOSED
CLOSED
DIASTOLE
SYSTOLE
DIASTOLE
0.1 s
-300

9. Valve Motion and Fluid Flow
Results
Valve Motion and Fluid Flow
Abrupt, erratic and delayed closing
Results in:
4. Greater occluder/housing impact and rebound at closure
5. Potential HITS and cavitation
Rebound
1. Valve 89% OPEN at zero flow
SLOW opening
causes opening stenosis
MOTION
FLOW
2. Late closure (in diastole)
SYSTOLE
3. Greater closing regurgitation
0.1 s

10. Valve Motion and Fluid Flow
Results
Valve Motion and Fluid Flow
GENTLE closing
(like bioprosthesis)
3. Infrequent small rebound
4. No indication for cavitation or HITS
2. End of systole closure and small closing reflux (like bioprosthesis)
RAPID opening
(like bioprosthesis)
1. Valve > ½ closed at zero flow
MOTION
FLOW
SYSTOLE
0.1 s

11. Does valve motion predict thrombogenicity?
Results
MOTION
FLOW
SYSTOLE
0.1 s

12. Opening Time x Displaced opening fluid volume
Results
OPENING index O
Opening Time x Displaced opening fluid volume
END
Opening
OPENING MOTION
VALVE FLOW
BEGIN Opening
OPENING
FLUID VOLUME
Opening time
Beginning of Systole

13. Motion closure ratemax x Backflow fluid volume
Results
CLOSING index C
Motion closure ratemax x Backflow fluid volume
CLOSING MOTION
MOTION
CLOSURE
RATEmax
END OF
CLOSURE
VALVE FLOW
BACKFLOW FLUID VOLUME
End of Systole

14. Results
1.0
0.9
OPENING index O
Opening Time x Displaced opening fluid volume
4.7
10.2
1.1
CLOSING index C
Motion closure ratemax x Backflow fluid volume
2.0
14.9
OPENING + CLOSING index T
BLOOD TRAUMA INDEX S
7.5
1.0 T
Tce

15. Proposed blood trauma index
Results
Proposed blood trauma index S
Valve opening and closing data is normalized to the tissue valve performance.

16. “The Mechanical Bioprosthesis”
Conclusions:
Bioprosthetic valve motion may have referentiality to benign, non-thrombogenic flow structure
Lapeyre-Triflo tri-leaflet mechanical valve motion is similar to that of bioprosthetic valves and very different from that of current mechanical valves
Lapeyre-Triflo tri-leaflet mechanical valve may require little or no anticoagulant therapy, and may represent
“The Mechanical Bioprosthesis”