Interpreting toe and ankle pressure curves and results when using PeriFlux 6000
Interpreting Curves and Results
PeriFlux 6000 | peripheral pressure made intelligent
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• Diagnosing Peripheral Arterial Disease
(PAD), Critical Limb Ischemia (CLI) and Non-
• Hands on, Tips and Tricks
• Interpreting Curves and Results
• Maintenance and Calibration
The aim of this document is to provide an
understanding for the interpretation of the curves
generated during pressure measurements.
Look for a Change in Perfusion
• Baseline perfusion > 20 PU
• Use local heating feature
• Hold pressure until the pulsatile signal disappears
Note that healthy controls can have
a “high” occluded perfusion even
though the vessels are closed. It is
important is observe a clear
change in perfusion.
• Good occlusion PU < 20.
• Clear difference between
occluded vessels and return of
Recording without heat
∆ low change
Pressure (mmHg) Pressure (mmHg)
Recording with heat
∆ big change
Local heat in laser Doppler probes:
• Increase the signal
• Facilitate interpretation
• Standardize measurements
Graphs recorded on the same patient without and with local heating.
Standardize Measurements with Heat
Thermostatic probe 457 on toe.
• Calcified vessels are stiff and difficult to occlude
• Common in diabetics, renal patients and
patients with critical limb ischemia
Normal patient – ankle pressure 105 mmHg
Diabetic patient with calcified arteries
Falsely elevated ABI
ABI > 1.4
of PAD / CLI
Clear pulsations at occlusion pressure
Measure the Toe Pressure Instead
• “Trust ABI when low but not when high.”
• Toe pressures have proven to be an excellent option for the
diagnosis of PAD in patients at risk for falsely elevated
ABI >1.4 values.
• Toe arteries are smaller and more easy to occlude.
• Accurate toe pressures require sensitive techniques such as
International Consensus on the Diabetic Foot and Practical Guidelines on the Management and Prevention of
the Diabetic Foot, International Working Group on the Diabetic Foot, 2012
Ankle pressure = 146 mmHg
ABI = 1.22
Toe pressure = 42 mmHg
Baseline tcpO2 = 43 mmHg
Combine Several Vascular Tests
Example: Male with painful left foot and amputated toes.
Results from several
tests will give a better
overview of the limb
Here : Patient with
clear PAD but no CLI.
Ankle pressure = incompressible arteries
Toe pressure = no toes
Baseline tcpO2 = 42 mmHg
Normal Ankle Pressure
and ABI. Is this really
reliable or the beginning
of media sclerosis and
falsely elevated ABIs?
Pressure markers are
automatically set at the
return of flow
Sometimes Adjustments are Required
• Laser Doppler probes are sensitive to motion
• Artifacts may trigger a faulty pressure registration
Biphasic Patterns upon Re-flow
C. HØyer. et al., Reliability of laser Doppler flowmetry curve reading for measurements of toe and ankle pressures:
intra- inter-observation variation, European Journal of Vascular Endovascular Surgery, 2014, in press
Clear distinction between phases Overlap between phases
Two phase (“bumps”) in the curves are:
• Arterial inflow (A) – veins are closed
• Unrestricted flow (V) – all vessels are open
• Place pressure marker at A
There is always a
possibility to exclude a
Best Practice – 3 Repetitions
• Always perform three (3) consecutive measurements
• Maximum variation between two pressures < 10 mmHg
• If the variation is more than 10 mmHg, perform another
Four consecutive ankle pressures.
The 3rd pressure differs more than 10 mmHg
compared to the other pressures and is discarded.
Be consistent. Develop your own internal rules.
Perform multiple measurements.