Arteriograph

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The TensioClinic Arteriograph is a diagnostic medical device, which can measure the effects of the classical cardiovascular risk factors (age, blood pressure, cholesterol level etc.) on the level of the individual. Prevention of stroke, heart attack, peripheral vascular disease can be achieved with the early detection of atherosclerosis. Making arterial stiffness parameters available for the primary care will make cardiovascular risk stratification more accurate.

Measuring arterial stiffness has become important regarding the latest ESC & ESH Guidelines. Until now, measured arterial stiffness parameters have been measured with the conventional Doppler method. Also it has recently been proved that central blood pressure has more significant predictive value on the therapy of cardiovascular diseases than the classical, brachial one (ASCOT-CAFE).

The new technology TensioClinic Arteriograph is the first evidence based medicine diagnostic device, which reportedly measures internationally accepted arterial stiffness parameters (Pulse Wave Velocity and Augmentation Index) together with central and peripheral blood pressure in a 3-minute session. The measurement itself looks like a regular blood pressure measurement, only the cuff needs to be inflated a couple of times in a single session.

PWV is the extent of bloodstream velocity and thus that of the rigidity of the vessel wall (aorta) as well, while AIX shows the extent of the resistance against which the heart has to pump. The narrower the vessels are (especially the smaller ones), the higher the resistance is, and the higher the afterload of the heart is. The resistance of those small vessels is determined primarily by the damage on the inner wall (so-called endothelial damage). Since the process of arteriosclerosis usually begins with endothelial damage, early measurement can only recognize higher AIX (often combined with slightly higher blood pressure). Later on, when the vessels are actually narrower and more rigid (sclerosis), this becomes visible from a higher PWV.

The device uses the results of medical researches, which showed that signals could be detected from the upper arm cuff, even if it is over-inflated with 35–40 mmHg (4.7–5.3 kPa) beyond the systolic BP, despite the completely closed brachial artery. Although these signals are extremely small, it is possible to detect them. It had been revealed that they contain information about the central hemodynamics. EU references are available for reinforcing the significance of this device, which can also evaluate the efficiency of applied cardiovascular therapy and for follow up of diabetic patients.

The measurement is based on the fact that during systole, the blood volume having been ejected into the aorta generates pulse wave (early systolic peak). This pulse wave runs down and reflects from the bifurcation of aorta, creating a second wave (late systolic peak). The return time (RT S35) is the difference (ms) between the first and the reflected systolic wave. RT S35 is related to the stiffness of the aorta. The difference of the amplitudes of the first and second systolic wave (AIx) depends on the tone of the peripheral arteries (endothel function). On the basis of these, aortic pulse wave velocity (PWV S35) can be calculated if the distance between the jugulum and the symphysis (Jug-Sy) is measured.

By analysing the amplitude of the reflected and the first wave, the Augmentation Index can be calculated (Aix), providing information on both the stiffness of the aorta (arteriosclerosis) and about the peripheral vascular tone. The closing of the aortic valve can be recognised on the wave taken at the systolic pressure + 35 mmHg (4.7 kPa), and as a result the ejection duration (ED) can be measured. By using the ED, the systolic (SAI) and diastolic area (DAI) can be calculated on the oscillometric pulse wave, recorded at diastolic pressure. SAI and DAI are in a close relation to the coronary perfusion, because it is mainly maintained in diastole.

Increased and abnormal arterial stiffness is the early sign of arteriosclerosis. The arterial stiffness is calculated from the above parameters, resulting in a classification of optimal, normal, increased or abnormal values. The measurement takes only three minutes. TensioClinic Arteriograph provides a screening method that detects arteriosclerosis in its early stage, when pathological procedures still could be positively influenced.

The Arteriograph needs to be wirelessly connected to a PC, having software installed that evaluates the measurement. The export version of the software makes the recorded data available in an Excel sheet. This makes the method a tool for the research of hemodynamic parameters.

In addition to the above parameters, blood pressure on the upper arm and aortic blood pressure are also measured. The latter is especially important with respect to the ‘workload’ of the heart.

The Arteriograph measures the following parameters in the same 3-min session: - Systolic and diastolic blood pressure (Sys, Dia) - Mean arterial pressure (MAP) - Pulse pressure (PP) - Heart rate (HR) - Augmentation index (Aix) - Systolic blood pressure on the aorta (SBPao) - Return time (RT S35) - Pulse wave velocity in the aorta (PWV S35) - Left ventricle ejection duration (ED) - Systolic area index (SAI) - Diastolic area index (DAI)

There are no peer reviewed publications to back the claims and statements presented here.

References can be found at: http://www.unimedic.co.uk/index.php?page=competence_centre