Pulse Wave Velocity, the GOLD standard for measuring arterial stiffness
PulseTrace PWV measures Arterial Stiffness between two locations of the arterial tree. It uses a Doppler probe to identify the arrival of the arterial pulse to calculate the Pulse Wave Velocity. This is the ‘gold-standard’ method for arterial stiffness measurement. Its uses include:
- Risk stratification
- Monitoring disease progression
- Evaluating treatment
Aortic arterial stiffness as measured by PWV between the carotid and femoral arteries (PWVcf ) is an independent predictor of cardiovascular risk. Ranges in large groups have been published and all major arterial stiffness outcome studies have used PWV as it it is the most widely validated and universally accepted measure of arterial stiffness. It is now recognised that in addition to hypertension, other risk factors accelerate the age-related stiffening of the aorta. Aortic PWV therefore acts as an integrative measure of cardiovascular risk.
Features
Minimum user training or special skills needed to obtain clinically valid results
Well tolerated by the subject
- Requires minimal training to obtain clinically valid results.
- Easy to locate good quality signals even when measuring deep arterial pulses found in obese patients.
- Well tolerated by the subject.
- Fast automated sequential measurements.
- Self contained, light and portable and does not require an external PC.
- High-resolution printer and colour ¼ VGA LCD display.
- Complete with all accessories in a sturdy case.
- User defined measurement sites.
- Waveforms, parameters and patient details storage.
- PC software for uploading and managing results.
- Future Proof' - can be upgraded via software downloads.
Key Users
- Hypertension Specialists and Cardiologists with an interest in Hypertension (or Hypertension/Stress Clinics where they exist): Risk Stratification, early detection of changes in the endothelium, treatment planning and drug studies.
- Diabetic Clinics and Diabetolgist: Monitor vascular disease, risk stratification, treatment planning and drug studies.
- Cardiovascular Drug Trials and epidemiological studies
Pulse Trace 'PWV Upload' Software
PWV Upload is a PC program that allows all the PulseTrace data to be uploaded to a PC for storage, viewing and reporting. For carotid/femoral data it includes a nomogram derived from published data for PWV comparisons.
It also includes a utility to export data to other programs e.g. Excel for statistics and analysis.
Specifcation
- Measurements:
- Examination/Storage:
- Doppler Transducer:
- Max. Audio Output:
- Doppler Waveform:
- ECG:
- Printer/Display:
- Power Supply:
- Dimensions:
- Weight:
- Standards:
- Environment:
- Transit Time in ms, between two sequentially measured Doppler waveforms from user-defined locations using the ‘R’ wave of the ECG as a timing reference. The average of ten waveforms from each location are used and the SD is calculated and displayed. PWV in m/s automatically calculated by dividing the time delay by the externally measured distance between locations. All waveforms are displayed and the detected onset of the pulse is marked. Heart Rate in beats/min. The heart rate is monitored at each measurement location over the ten waveforms. The user is advised if there has been a significant change.
- User defined measurement sites/200 tests including waveforms
- 4MHz ± 1% continuous wave Doppler pencil probe
- 500mW rms typical (volume control on interface
- Bi-directional zero crosser (forward and reverse) with AGC
- Three lead set length 1000mm European colour code with tab-snap clips, no additional components for defib protection
- 320 dot per line internal thermal printer/¼ VGA Colour LCD
- Input 100-250V 50-60Hz DC output 12V 500mA
- 337 x 140 x 45mm (when display closed) Transducer/ECG interface 190 x 100 x 45mm
- Unit weight 1.1kg. Packed weight with carry case and accessories 2.6kg
- Type B device, CE approved (Directive 93/42/EEC)
- Complies with directive EN60601-1-2 electromagnetic compatibility
Micro Medical has used the Doppler method to detect the onset of flow in the artery. Doppler pulses are recorded sequentially in 2 different arterial sites and compared using the R-wave of the ECG shown here
The PulseTrace PWV automatically steps the user through a programmed examination providing extremely simple operation and automatic calculation of the PWV between any two-user selected/defined locations. By using a 4MHz Doppler probe, signals from both the carotid and femoral sites can be easily found in all subjects including those obese or muscular necks.
Validation
PWV is the most widely validated and universally accepted measure of arterial stiffness (Ref 33-36). The observation that aortic PWV increases with age and blood pressure was recognized in the 1930’s by Hallock (Ref 37) and Haynes et al (Ref 38). It is now recognized that in addition to hypertension, other risk factors accelerate the age-related stiffening of the aorta. Aortic PWV therefore acts as an integrative measure of cardiovascular risks (Ref 7, 8, 22, 23, 30, 39, 40).
Because arterial stiffness is an independent predictor of cardiovascular risk, there is now great interest in its use for cardiovascular risk stratification and to monitor drugs that can alter/improve aortic stiffness (Ref 41).
Bibliography
Arterial Measurement Page
