Large artery stiffness and endothelial function testing - A practical solution

PulseTrace PCA 2 was developed specifically for the professional who demands a quick and practical solution for the assessment of large artery stiffness and endothelial function. This 'next generation' Micro Medical PulseTrace is designed for use in clinical practice, to aid early detection, treatment, and management of cardio-vascular disease.

Arterial Stiffness Measurement

The PulseTrace PCA 2 estimates large artery stiffness from the pulse waveform obtained at the finger (digital volume pulse: DVP) with an infra-red sensor (photoplethysmography). It is extremely easy to use, operator independent and is very well accepted as a routine measurement by the patient. The speed at which the pulse travels along the arterial tree is directly related to arterial stiffness.

Measuring the time it takes for the pulse waves to travel through the arterial system provides a simple but accurate way of measuring arterial stiffness. The shape of the volume waveform in the finger is directly related to the time it takes for the pulse waves to travel through the arterial tree. This very important observation is used by the Micro Medical PulseTrace and makes it a powerful noninvasive tool for the assessment of vascular changes.

The Clinical Value of Arterial Stiffness

• Arterial stiffness is an independent predictor of cardiovascular risk.
• Arterial stiffness is a measure of target organ damage indicating the need for lifestyle and drug intervention
• The DVP waveform is independent of local changes of the vasculature but determined by large artery stiffness (estimated by SI) and vascular tone (estimated by RI). SI is highly correlated with PWV, as shown below, and RI is determined by the systemic vascular tone

Endothelial Function Measurement

The DVP waveform is also very sensitive to the vascular tone of the whole arterial tree. PulseTrace 1000 automatically analyses the finger pulse to determine a measure of arterial stiffness and a measure of vascular tone. The change in the DVP waveform in response to an endothelial dependant vasodilator such as salbutamol (albuterol) can be used to assess endothelium function. Salbutamol can be administered using an inhaler making this a very simple test to perform in the clinic or at the bedside.

The Pulse Trace 1000 uses a high fidelity photo-plethysmography transducer with signal conditioning circuit to obtain an extremely accurate and noise free signal of the DVP waveform. This is a simple non- operator dependent measurement, which is well tolerated by the subject. In addition, a unique control system maintains the light transmission at the optimum level to accurately follow blood volume changes, independent of the subject's finger size.

The many advanced features include; a high-resolution touch sensitive colour display giving real time blood volume pulse waveforms; signal averaging with advanced rejection/acceptance criteria; and user customisation of many of the analysis parameters. The Pulse Trace measurements may be reviewed at the time, during the test, or at a later date from memory, which can hold up to 10,000 test results including the waveform. The unit can be connected to the USB port of a PC running PCA 2-Upload software. This allows the database including the waveforms to be uploaded to a PC for viewing, storage, report generation, data trending and export to other applications.