ffr: pitfalls · etp course 2014, sophia-antipolis ffr: pitfalls . equalization etp course 2014,...
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FFR: pitfalls
Gabor Toth G.
Cardiovascular Centre Aalst
OLV-Clinic Aalst, Belgium
ETP course 2014, Sophia-Antipolis
Fractional flow reserve measurement
Accurately measured coronary pressure (Pd)
Accurately measured aortic pressure (Pa)
Maximal hyperaemia
FFR
X X
X X
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Pitfalls can be related to.... Preparation
• Calibration
• Equalization
Measurement
• Drifting
• Wedging
• Whipping
• Hyperaemia
Tracing interpretation
• Cursor position
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Preparation
• Calibration
• Equalization
Measurement
• Drifting
• Wedging
• Whipping
• Hyperaemia
Tracing interpretation
• Cursor position
Pitfalls can be related to....
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Calibration
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
‘teaching’ the system, what is zero pressure
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Calibration: PressureWire
• Fill the tube of the wire with saline
• Wait a 30-60 sec to have the wire completely and stably wet
• Perform calibration afterwards
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Equalization
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
‘teaching’ the two systems, to be synchronous
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Pa Pd =
Equalization
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
After equalization DO NOT CHANGE YOUR SETTING
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Preparation
• Calibration
• Equalization
Measurement
• Drifting
• Wedging
• Whipping
• Hyperaemia
Tracing interpretation
• Cursor position
Pitfalls can be related to....
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Preparation
• Calibration
• Equalization
Measurement
• Drifting
• Wedging
• Whipping
• Hyperaemia
Tracing interpretation
• Cursor position
Pitfalls can be related to....
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Drifting
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
When the two systems forget to be
synchronous...
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Clues to identify drift
• Curves are identical in shape
• Curves are shifted paralell
• Dicrotic notch is well visible on both
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Drift Same morphology
Paralell shifting
Dicrotic notch well visible
True Gradient Different morphology
Dicrotic notch not visible
Gradient or Drift??
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Pa Pd ≠
Post-measurement check
= Drift!!!
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Equalize again
Measure again
Wedging
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Aortic pressure is inaccurately measured...
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
4 mm 2.4 mm 36 %
8F
4 mm 2.1 mm 27 %
7F
4 mm 1.8 mm 20 %
6F
Induced area stenosis
Size of the guiding catheter
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
3 mm 2.4 mm 64 %
8F
3 mm 2.1 mm 49 %
7F
3 mm 1.8 mm 36 %
6F
Size of the guiding catheter Induced
area stenosis
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Wedging guiding catheter
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Disengaged guiding catheter
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Wedging guiding catheter
FALSE VALUE 0.88 TRUE FFR 0.66
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Whipping
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Coronary pressure is inaccurately measured...
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Whipping
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Hyperaemia
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Without maximal hyperaemia there is
no FFR measurement
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Insufficient hyperaemia
Underestimation of
the gradient
Overestimation of
the FFR
Underestimation of
disease
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Preparation
• Calibration
• Equalization
Measurement
• Drifting
• Wedging
• Whipping
• Hyperaemia
Tracing interpretation
• Cursor position
Pitfalls can be related to....
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Preparation
• Calibration
• Equalization
Measurement
• Drifting
• Wedging
• Whipping
• Hyperaemia
Tracing interpretation
• Cursor position
Pitfalls can be related to....
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Position the cursor to the lowest value where indeed FFR was measured
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Position the cursor to the lowest value where indeed FFR was measured
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Pitfalls can be related to....
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Preparation
• Calibration
• Equalization
Measurement
• Drifting
• Wedging
• Whipping
• Hyperaemia
Tracing interpretation
• Cursor position
Fractional flow reserve measurement
Induce proper maximal hyperaemia
Interpret the tracing appropriately
Obtain accurate measurements
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Thank you for your attention!
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Thank you for your attention!
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Setting in the cathlab
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
• Aortic pressure is measured by the fluid filled
guiding catheter
• Its value is a relative pressure, compared to
the reference, measured at the transducer
• Height of the transducer has a measurable
impact on the value
Calibration: Position of the Transducer
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Pressure TOO LOW
Pressure TOO HIGH
Pressure OK
Calibration: Position of the Transducer
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Pressure TOO LOW
Pressure TOO HIGH
Pressure OK
Calibration: Position of the Transducer
ETP course 2014, Sophia-Antipolis
FFR: pitfalls
Setting in the cathlab
ETP course 2014, Sophia-Antipolis
FFR: pitfalls