This document discusses using 4Fr catheters to perform FFR measurements. It notes that 4Fr catheters have a smaller diameter than typical 5-7Fr guide catheters used for angiography and intervention. While 4Fr catheters allow for a smaller wrist access site, they have limitations including only being used for diagnostic purposes and not direct PCI if needed. The document outlines techniques for optimizing FFR measurements using 4Fr catheters, including ensuring the lumen is well flushed and the transducer is not damped. It also discusses needed improvements to 4Fr catheters and techniques. The overall goal is to use the smallest diameter access needed for diagnosis to maximize long-term function of the radial artery

1. FFR using 4Fr catheters: Can
Slender Technique Work Here?
Ian C Gilchrist, MD, FACC, FSCAI
Professor of Medicine
Penn State’s Hershey Medical Center
Heart & Vascular Institute
Hershey, PA
Nothing to disclose

2. 4 French Feasibility
Yadav, Gilchrist. JACC 2014;64(11_S)
Pop Test Pulse-Duplicator
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Area 4-F catheter = 3.14 mm2
Area 0.014” wire = 0.10 mm2

3. Example: Taking it a Down a Notch
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50 year old woman with recurrent atypical pain
RCA stent last year via left radial
Stress test was equivocal
Small, light framed woman
Definitely wants a wrist approach again

4. Plan
Right radial
5F sheath
Option for intervention
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5. 0.035” wire stopped at sheath
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Right forearm angiogram via sheath
High origin of radial from brachial artery

6. Switched to 4F
LCA- 4F JL3.5 RCA- 4F JR4.0
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7. Not Sure of RCA at Stent
stent
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Options?
1. Go down under (groin)?
2. Contalateral radial?
3. Ulnars?

8. FFR- 4 French Multipurpose
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9. General Coronary Set-Up
Hydrostatic transducer (Ao)
Electronic transducer (Co)
Computer
FFR, iFR, etc
Flushed Catheter
Clean Signal
No Catheter Damping
Wire
Normalized
Calibrated
Positioned
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10. Effect of Guiding Catheters in
Different Coronary Ostia
Toth, J Am Coll Cardiol. 2016;68(7):742-753.
5-F
6-F
7-F
4-F Catheter
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Area 4-F catheter = 3.14 mm2
Area 0.014” wire = 0.10 mm2
4F
0.014” wire

11. Lumen
Longitudinal Effects
THROMBIN CONTRAST
WHAT HAPPENS TO THE
PULSE WAVEFORM?
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Ideal pressure wave
Ideal pressure wave
central obstacle
Lumen1
Lumen2

12. 4F Catheter Characteristics
Diagnostic only in US
Can’t directly do PCI if needed
Interface between wire & catheter
wall may add friction
Thermo-stability poor
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13. 4-F Technique
Less forgiving than larger French
Use fresh catheter & rapidly introduce wire
Meticulous FFR/iFR technique needed
• Confirm lumen is well flushed
• Transducer or catheter is not-damped
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Lack of immediate interventional
capacity may temper patient choice

14. Improvements Needed
Better understanding of wire/internal catheter
interface to improve coeffiecent of friction
4-F guides or equivalent (FFR catheters?)
Potential for smaller catheters if sensor also
placed on distal catheter
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Goal: Use of the smallest diameter access into the radial artery required
for diagnosis will maximize long-term radial artery function

15. Thank you
icg1@psu.edu icg 2016