The aim of this document is to provide an understanding for the interpretation of the curves generated during toe and ankle pressure measurements using PeriFlux 6000.

1. Interpreting Curves and Results
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2. Disclaimer
The information contained in this document is intended to provide general
information only. It is not intended to be, nor does it constitute, medical advice.
Under no circumstances is the information contained in this document to be
interpreted as a recommendation for a particular treatment for specific
individuals. In all cases it is recommended that clinicians perform their own
interpretations of data in conjunction with the clinical assessment of their patient.
Due to Perimed’s commitment to continuous improvement of our products, all
specifications are subject to change without notice.
All information and content in this document is protected by copyright. All rights
are reserved. Users are prohibited from modifying, copying, distributing,
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public purposes. All responsibility for any liability, loss or risk, personal or
otherwise, which is incurred as a consequence, directly or indirectly, of the use
and application of any of the material in this document is specifically disclaimed.

3. • Diagnosing Peripheral Arterial Disease
(PAD), Critical Limb Ischemia (CLI) and Non-
healing Wounds
• Hands on, Tips and Tricks
• Interpreting Curves and Results
• Maintenance and Calibration

4. Introduction
The aim of this document is to provide an
understanding for the interpretation of the curves
generated during pressure measurements.

5. All curves are not as perfect as this one …

6. Look for a Change in Perfusion
• Baseline perfusion > 20 PU
• Use local heating feature
• Hold pressure until the pulsatile signal disappears
Pressure (mmHg)
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
flow.
Perfusion(PU)
Arm
Ankle
∆
∆
∆
∆

7. Recording without heat
∆ low change
Pressure (mmHg) Pressure (mmHg)
Perfusion(PU)
Perfusion(PU)
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
0
100
50
0
100
50
Thermostatic probe 457 on toe.

8. • Calcified vessels are stiff and difficult to occlude
• Common in diabetics, renal patients and
patients with critical limb ischemia
Incompressible Arteries
Normal patient – ankle pressure 105 mmHg
Pressure (mmHg)
Perfusion(PU)
Diabetic patient with calcified arteries
Pressure (mmHg)
Perfusion(PU)
Arterial calcification
Falsely elevated ABI
ABI > 1.4
Falsely elevated
ankle pressures
Underestimation
of PAD / CLI
Clear pulsations at occlusion pressure
Occlusion

9. 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
laser Doppler.
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

10. Right foot:
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
circulation.
Here : Patient with
clear PAD but no CLI.
Left foot:
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?

11. Adjusting Pressure
Markers?

12. Standard Recording
Pressure markers are
automatically set at the
return of flow

13. Toe pressure
BloodPerfusion
Time (s)
Sometimes Adjustments are Required
• Laser Doppler probes are sensitive to motion
• Artifacts may trigger a faulty pressure registration

14. 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
Time (s)
Perfusion(PU)
0
100
200
Time (s)
Perfusion(PU)
0
100
200
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

15. Exclude Measurements
There is always a
possibility to exclude a
measurement if
necessary.

16. 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
measurement
1 145
2 146
3 128
4 143
Four consecutive ankle pressures.
The 3rd pressure differs more than 10 mmHg
compared to the other pressures and is discarded.

17. Summary
Be consistent. Develop your own internal rules.
Perform multiple measurements.
Think physiologically!

18. Thank You!
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