1. The Effect of FFR Wire Design on Function
Jeff Chambers, MD FSACI, FACC
Director Cardiac Cath Lab
Metropolitan Heart and Vascular Institute
Mercy Hospital , Minneapolis, MN

2. Jeff Chambers, MD Disclosures Consulting CSI Boston Scientific
ACIST Medical 

3. Background Utilization of FFR has revolutionized the treatment of CAD
Allows determination of lesions severity
Which lesions require treatment
Which are safe to defer
Has decreased unnecessary PCI
2007
2008
2009
2010
2011
2012
2013
2014
2015E
FM Wires / Year

4. FFR Timeline COMPLEXITY Multivessel STEMI Famous - STEMI FAME II
FAME III
FFR Introduced
DEFER
Functional Syntax
FAME
1990
1995
2000
2005
2010
2015

5. Tortuosity, Acute angles, Jailed side branch
Difficult Anatomy
Tortuosity, Acute angles, Jailed side branch

6. Requirement for Optimal FFR
Rapidly access the lesion of interest
Be certain the information is accurate
Lack of drift
Ability to equalize or zero easily
Pull back gradients can be performed
A good platform to use to perform PCI
Shapeable tip
Adequate support in the body of the wire
Kink resistant
Ability to obtain repeat measurements quickly
Able to reconnect without loss of accuracy
Connects to a storage medium
PACS system
Hemodynamic system

7. Sensors For FFR devices
Physical phenomenon
Sensor System
Measurement Output
Piezo Electric Wires
Volcano - Verrata™ Pressure Guide Wire
St. Jude - PressureWire™ Aeris™ Guidewire
Optical Fiber Wires
Opsens Medical – OptowireTM
Boston Scientific – COMETTM wire
Optical Fiber Catheter
ACIST - NAVVUS™ Rapid Exchange FFR Microcatheter

8. Piezo-Electric Transducer
Piezoelectricity  is the electric charge that accumulates in certain solid materials such as crystals, in response to applied mechanical stress.

9. Electric Cables Connect to Sensor
Piezo –Electric Transducer

10. St Jude PressureWire™ X Guidewire
New flat corewire design for a softer, more durable tip with excellent shapeability, re-shapeability and shape retention*
Hydrophilic coating with reduced friction for improved device delivery and compatibility**
Proprietary, high-fidelity sensor technology for measurement of intravascular pressure
Wireless radio technology for easier maneuverability and reduced clutter across the sterile field
Hydrophilic-coated polymer sleeve protects cabling and electronics from fluids
St Jude Web site

11. Volcano - Verrata™ Pressure Guide Wire
Volcano Web Site

12. Fiber Optic Sensors Can function in harsh environment :
Intensive EMI, high temperature, chemical corrosion, high pressure, high voltage
Light weight and small size
High degree of biocompatibility
Excellent performance:
High sensitivity
Large bandwidth
Capable of long range operations

13. Optical Fibers
An optical fiber consists of a thin, low-loss glass wire with a center or core region having a slightly higher refractive index than its surrounding region or cladding.

14. Fiber Optic Pressure Transducer
Blood pressure causes the sensor’s distal face to flex inward, reducing the width of the cavity.
The incoming light impulse is reflected off the 2 mirrors
This controls the wavelength of outgoing light pulse that is transmitted back to the console for analysis and display
Pinet E, Journal of Sensors 2009

15. Fiber Optic Wire Design
Symmetrical and concentric guide wire construction closely mimic the full body of standard PCI guidewire for torque response
The use of Nitinol for improved torquability and kink resistance.
The combination of laser cut stainless steel tube and Nitinol core tube provides excellent support
Larger diameter Nitinol core – enhanced torque characteristic
Optical fiber
Laser cut spiral stainless steel

16. Boston Scientific COMETTM Wire
Asahi Hydrophilic Coating
(Asahi Ultrathin film coating process)
Silicone Coating
Spring Coil
Stainless Steel Core
Laser-cut Hypotube
(Synergy’s technology)
ACTONE

17. Opsens Medical – OptowireTM

18. ACIST - NAVVUS™ Rapid Exchange FFR Microcatheter

19. Differences In the Technologies
Tip transition
Torque/Tracking
Accuracy
Drift
Pull back ability
Reconnection

20. Traditional Piezo-Electric FFR wire structure
Hollow Wire
* Hollow wire body for
sensor connection
Sensor Housing
Piezoelectric sensor
Solid rigid housing
Transition Zone
Tip
Separated from wire body by the sensor

21. Tip Transition
Optical FFR Sensor
Opsens Medical – OptowireTM

22. Tip Load 3
/003
COMET TM
Asahi Tip with ACTONE

23. Whipping Effect 3 wires Hollow Core
1. St. Jude Medical. Data on File: R3149 PressureWire Generation 8 PMS Report

24. TORQUABILITY TESTING 1:1 Comet FFR wire Available FFR wires
Optical Fiber
Torque Transfer

25. FLEXIBILITY TESTING
REF 1
REF 1I

26. PressureWire™ Aeris™ Guidewire Verrata™ Pressure Guide Wire
Accuracy and Drift
St. Jude
PressureWire™ Aeris™ Guidewire
Volcano
Verrata™ Pressure Guide Wire
Boston Scientific
COMETTM wire
ACIST
NAVVUS™ 
Microcatheter
Drift
< 7 mmHg/ hour
Not specified in IFU
< 3 mmHg/ hour
Accuracy
+/-3%, mmHg
+/- 3 mmHg, -30~300 mmHg,
+/- 3% or
+/- 3 mmHg

27. Pull Back From: Functional Measurement of Coronary Stenosis
Figure Legend:
The pressure recording shows that all the disease in the LAD combined is responsible for inducible ischemia (FFR 0.74) and indicates the exact origin of the gradient (arrows). The numbers 1 and 2 in the angiogram correspond to the respective numbers in the pressure tracings Abbreviations as in Figures 2 and 5.
J Am Coll Cardiol. 2012;59(12): doi: /j.jacc
Copyright © The American College of Cardiology. All rights reserved.

28. Pull Back ACIST catheter can be used with any wire
All wires require re-crossing of the lesion for a pull back

29. Ability To Reconnect COMET™ Pressure Guidewire
Optical Fiber reconnection is not affected by moisture
Less likely to be affected by blood or contrast
COMET™ Pressure Guidewire
VOLC
Reliable re-connection (does not have issues with moisture like electrical does)
Electrical contacts required
Free spinning connection (does not impair torque like electrical connections do)
Electrical contacts required
SJM

30. Summary of Piezoelectric and Free-spinning connection
Optical FFR systems
Signal Processing
Unit R
Electrical Signal
Detachable Adaptor
2nd Half Wheatstone Bridge
Piezoelectric Sensor
1st Half Wheatstone Bridge
Cable or Wireless
Moisture causes drift
Asymmetric design may cause poor torque
Cable connection may cause:
Poor torque
Kink prone
Signal loss
Wireless is feasible
Optical Processing
Unit
Detachable/Spinnable Connector
Optical Sensor
Optical Signal
Optical Cable
Not affected by moisture
Symmetrical design
Wireless is difficult
Free-spinning connection
Robust signal
Weightless handle

31. Conclusions
FFR is being used to assess increasing complex lesions - pushing the technology
Properties of the device or wire are limited by the design and manufacturing requirements of the sensor
Optical Fiber technology offers unique properties that allow design changes.
Optical Fiber Technology has improved performance and may increase accuracy
The new wire designs may increase adoption of FFR which may ultimately improve patients care.