BE1020102A3 - DEVICE AND METHOD FOR MEASURING HEART RISK. - Google Patents

Abstract

The present invention relates to a device for the measurement of cardiac risk, in particular an endothelial dysfunction using a measurement of the dilation reaction of an artery following an imposed stress, characterized in that it comprises means for measuring blood flow.

Description

DEVICE AND METHOD FOR MEASURING RISK

HEART

Object of the invention

The present invention relates to the non-invasive assessment of cardiovascular risk by endothelial function: Flow Mediated Dilation (FMD).

[0002] Endothelial dysfunction is considered the first step of arteriosclerosis. Deficient endothelial function is recognized as the signal for a pathological process of cardiovascular disease. The evaluation and characterization of endothelial function in the diagnosis of cardiovascular diseases are topics of clinical importance and research.

[0003] Endothelial function is often evaluated by the Flow Mediated Dilation (FMD) which represents the relaxation of an artery, typically the brachial artery, following the action of the endothelium which acts because of the increase in blood flow. Brachial artery responsiveness is frequently used as a non-invasive ultrasound assessment of FMD that indicates the endothelium-dependent response to stress. This measurement is a marker of increased cardiovascular risk and correlates with poor endothelium-dependent relaxation in the coronary arteries.

However, the ultrasound measurement of FMD remains a so-called "dependent user" measure in the sense that the result of this will depend on the operator.

Main characteristic elements

FLOMEDI offers a brand new evaluation system of the endothelial function, called

CardioVaRisk, which is a tool that uses photoplethysmography for automatic measurement of endothelial function, and keeps the main principles of the "Flow Mediated Dilation" technique. It allows doctors to detect cardiovascular risks.

The CardioVaRisk device that allows the non-invasive evaluation of cardiovascular risk and endothelial function essentially comprises the following elements: a cuff (1) if possible with automatic inflation and to obtain at least partial occlusion and which will serve as stress stimulation, at least one and if possible two measurement probes (2) and (3), the photo-plethysmographic signal which will respectively be placed on the hyperemic finger and a control finger, finally, an acquisition box measurements (4) obtained by the two probes (2) and (3).

[0006] CardioVaRisk is a new system for the evaluation of cardiovascular risk. The CardioVaRisk device is an innovative tool that uses photo-plethysmography to detect endothelial dysfunction and to analyze heart rate variability (HRV) in both the time and frequency domains. This system is fully automatic, accessible to all and very easy to use.

[0007] The CardioVaRisk device offers an easy-to-use system with the following features:

Acquisition of the photo-plethysmographic signal (hyperemic finger and possibly control finger), automatic inflation cuff for occlusion (stress stimulation), - non-invasive diagnostic aid for cardiovascular diseases with evaluation of endothelial function ( arterial reactivity),

Automatic analysis of the results,

Analysis of heart rhythm variations, accessible to all,

No need to invest in ultrasonic equipment,

Very easy and fast to use,

Report in Excel and Word,

Expanded the target of users,

Reduced purchase cost.

The product "CardioVaRisk" includes a photo-plethysmographic measuring device (at the finger) giving an indication of volume / blood flow at the peripheral level. And following a very precise measurement protocol, it will give us a precise image of a possible endothelial dysfunction and consequently the cardiovascular state of the patient.

This product makes it possible to evaluate the endothelial function without the use of an ultrasound system. It is therefore addressed to another type of end users much wider than the products of the state of the art, including general practitioners.

The principle of operation of the device according to the present invention is described in detail in Fig.2 according to a first embodiment.

Currently, the plethysmographic signal (optical measurement: photo-plethysmography) is acquired using the electronic circuit, which has been developed, and transmits in real time the physiological trace to the PC, via a USB port, and this, in order to be analyzed.

The system provides the possibility of making recordings of photo-plethysmographic curves. The data / signals from the acquisition interface are transmitted via a USB port to the PC for display and analysis in the software.

In addition to the electronic circuit for acquiring the photo-plethysmographic signal, there is provided an additional circuit for automating the inflation and deflation of the cuff, which will be used as a tourniquet to generate the stress (stimuli) that generates the production of NO which has a vasodilating effect of the arteries.

An example of a photo-plethysmographic curve is shown in detail in FIG. 3 and in FIG.

In particular, the software will: => the integration of a new control module to reduce noise during startup and shutdown of the pump and the solenoid valve, => the development of the new software package. data analysis, user interface and acquisition interface, => calculation of the real-time heart rate during acquisition, => definition of Heart Rate Variability (HRV: temporal, non-linear and frequency statistics), = > adjustment of the tourniquet pressure from the acquisition interface, => the software control and adaptation circuit.

Previously, a single measurement line was used which was a hyperemic line, which allowed to visualize the vasodilatation of the arteries following a stress performed using the withers. But after several tests and research, it was highlighted that some results of healthy patients did not meet expectations. After investigation, it appeared that some patients, during the stress (occlusion of the artery using the tourniquet), underwent a vasoconstriction following a too intense stress. The vasodilation phase (after loosening the tourniquet) simply returned the artery to its normal state. With both vasoconstrictor and vasodilator phases canceling, the vasodilator phase was not visible using a single measurement line. To this end was added an additional measurement line, control line at the index of the other hand: (right hand), to visualize this phase of vasoconstriction which allows to take into account a reference when analyzing the results.

An example of an embodiment of a measurement is shown in detail in FIG. 5a (new analysis interface), FIG. 5b (HRV analysis), FIG. 5c (interface of FIG. acquisition) and Fig.5d (hyperemic measurement and control finger).

The following optimizations can be envisaged: programming of the controller for the acquisition of the data: obtaining a higher number of data samples in order to refine the signal and the acquisition curve, for example passes of 35 samples per sec at 150 samples per sec (Signal image), => at sampling from 250 to 1000 samples per sec (to have a correct time base) because during the acquisition, there is a risk of data loss and therefore a risk of having an erroneous time base, = 5 optimization of the code for the interpolation of the data: x samples for the entire acquisition.

The interpolation took 10 min of treatment with the optimization of the code the duration of the treatment was passed to 1 sec, = 5 optimization of the electronic card for decrease of the artifacts, => improvement of the filter to increase the dicrote wave of the plethysmographic signal , => automatic compensation of the pressure during the 5 minutes of occlusion. If during the 5 minutes of ischemia, the pressure in the cuff comes down too low, the pump restarts to reach again the pressure set by the user.

Examples of sampling are shown in Fig.5a and Fig.5b and their respective response to Fig.5c and Fig.5d.

According to another particularly preferred embodiment, it will also be possible to associate a temperature acquisition and a pressure acquisition with the aid of appropriate temperature and pressure probes. This embodiment is described in more detail in Fig.7a and Fig.7b.

The "redesign" of a completely new user interface has been completed to make its navigation much more user-friendly.

Claims (8)

1. A device for measuring cardiac risk, in particular an endothelial dysfunction using a measurement of the dilation reactivity of an artery following an imposed stress, characterized in that it comprises means measuring blood flow. 2. Device according to claim 1, characterized in that it further comprises an interface for capturing, measuring and interpreting the signal, preferably for one minute before stress, throughout the duration of stress and during the at least five minutes after the imposed stress. 3. Device according to claim 1 or 2, characterized in that it further comprises means preferably autonomous, to induce stress to said artery. 4. Device according to claim 3, characterized in that the means for inducing stress are constituted by a tourniquet or a blood pressure monitor. 5. Device according to any one of the preceding claims, characterized in that the blood flow measuring means comprise at least one optical sensor, preferably an optical sensor performing a measurement in the infrared. 6. Device according to claim 6, characterized in that the stress measuring means comprise two identical sensors - a sensor intended to serve as a reference and which will be placed on a finger not undergoing stress - a sensor intended to carry out the measurement. stress and post-stress 7. Device according to any one of the preceding claims, characterized in that it also comprises means for measuring temperature and pressure by tonometry. 8. Software for the implementation of a method for measuring cardiac risk and in particular endothelial dysfunction using the device according to any one of the preceding claims.