Assessment of Three Instruments for the Non-invasive Measurement of Arterial Stiffness.

Assessment of Three Instruments for the Non-invasive Measurement of Arterial Stiffness.

The ASI Non-Invasive Arterial Stiffness Screening Device (ASI Device) is an investigational device under development for the non-invasive assessment of arterial stiffness. The ASI Device is considerably smaller and more cost effective than its commercially available counterparts. As the device is readily portable, it is intended to be targeted for use in the community (or at home), as opposed to within the hospital or clinic setting only. However, as the device is still under development, it is not known whether it is capable of determining arterial stiffness with the same sensitivity and consistency as those already in commercial use. An added variable is the fact the sensor for the ASI Device is located on the fingertip.

Validation is a prerequisite for obtaining Health Canada approval of devices for diagnostic purposes. The ASI Device has not been tested against other instruments capable of providing similar measurements. Therefore, a clinical trial to compare the ASI Device against similar devices is necessary. The study will compare measurements of arterial stiffness and other central haemodynamic parameters obtained with the ASI Device against similar measurements from devices that have already been approved for this purpose by Health Canada/United States Food and Drug Administration (FDA).

This is an exploratory, proof of concept, open sequential registration comparative study designed to establish the utility and accuracy of the ASI Non-Invasive Arterial Stiffness Screening Device (ASI-Device) for the non-invasive vascular assessment of arterial stiffness relative to other such devices already approved and commercially available in Canada and the United States.

The pressure exerted from the contraction of the heart creates a wave form, which travels down the individual's arterial trunk to all parts of the body. The velocity (speed) at which this wave form travels can serve as an indicator of the degree of arterial stiffness. The faster the speed of travel of the pulse wave the stiffer the arteries. It has been demonstrated in other studies that the contour (shape) of the waveform can be affected by the pulse wave velocity and that analysis of this shape is an acceptable surrogate for determining the pulse wave velocity and ultimately determining the severity of arterial stiffness. This method of analysing the contour of the pulse wave to determine the severity of arterial stiffness is called pulse wave analysis (PWA).

The ASI Device non-invasively measures the severity of arterial stiffness derived through pulse wave analysis. The study will compare measurements of arterial stiffness and other central haemodynamic parameters, as derived through pulse wave analysis obtained with the ASI Device, against similar measurements from the SphygmoCor Px System from AtCor and the CR-2000 CV Profiler from Hypertension Inc, devices that already have approval for this purpose by Health Canada and/or the United States Food and Drug Administration.

Three groups of individuals will be sought;

1. Healthy participants (n=25)
2. Persons with Type 2 Diabetes and/or Obesity (n=15)
3. Persons with a diagnosed Cardiovascular/Vascular disease (such as CAD or PAD) (n=15)

Participants will be asked to provide written informed consent prior to participation in the study. Eligible participants will be asked to attend an in-person visit where they will undergo the non-invasive vascular testing. Testing will be comprised of:

1. Pulse Wave Analysis using the ASI Device
2. Pulse Wave Analysis using the SphygmoCor Device
3. Pulse Wave Analysis using the CR-2000 CV Profiler

Although pulse wave contour analysis (PWA) has been demonstrated to be an acceptable surrogate for the assessment of arterial stiffness, Pulse Wave Velocity has been the gold standard for the assessment of arterial stiffness. As such, the VP-1000, a non-invasive vascular screening device, will also be used to measure pulse wave velocity.

Inclusion Criteria:

Participants of the Healthy Group must meet the following criteria to be eligible for participation in the study:

1. Healthy male or female, greater or equal to 20 and less than or equal to 70 years of age;
2. Willing to comply with the protocol requirements;
3. Willing to provide informed consent.

Participants of the Obese/Type 2 Diabetes Group must meet the following criteria to be eligible for participation in the study:

1. Male or female, greater or equal to 20 and less than or equal to 70 years of age;
2. Presence of clinically diagnosed Type 2 Diabetes, and/or a body mass index (BMI) > 30;
3. Willing to comply with the protocol requirements;
4. Willing to provide informed consent.

Participants of the Vascular Disease Group must meet the following criteria to be eligible for participation in the study:

1. Male or female, greater or equal to 20 and less than or equal to 70 years of age;

2. Documented evidence of atherosclerosis as manifested by one of the following:

   1. documented myocardial infarction;
   2. documented CAD as defined as >70% stenosis of an epicardial coronary artery;
   3. documented PAD including those with claudication as defined by an ankle brachial index of <0.9;
   4. angiographically documented carotid or lower limb stenosis of >50%

3. Willing to comply with the protocol requirements;

4. Willing to provide informed consent -

Exclusion Criteria:

Participants of the Healthy Group will be excluded if they have any of the following:

1. Presence of a clinically diagnosed disease affecting the circulatory, respiratory, immune, skeletal, urinary, muscular, endocrine, digestive, nervous or reproductive system that requires medical treatment;
2. Cigarette/cigar smoking, current or within the last 6 months;
3. Current (within the last 30 days) bacterial, viral or fungal infection;
4. Taking any prescribed medication (with the exception of birth control or HRT) within the last 3 months or over-the-counter medication within the past 72 h;
5. Pregnancy;
6. Amputation or malformation of any limb or extremity (fingers, leg, or arm) which would impede the placement of sensors, probes, or blood pressure cuffs.

Participants of the Obese/Type 2 Diabetes Group will be excluded if they have any of the following:

1. Documented evidence of atherosclerosis as manifested by one of the following:

   1. documented myocardial infarction;
   2. documented CAD as defined as >70% stenosis of an epicardial coronary artery;
   3. documented PAD including those with claudication as defined by an ankle brachial index of <0.9;
   4. angiographically documented carotid or lower limb stenosis of >50%
   5. having had a documented previous intervention for CAD or PAD.

2. Cigarette/cigar smoking, current or within the last 6 months;

3. Current (within the last 30 days) bacterial, viral or fungal infection;

4. Taking over-the-counter medication within the past 72 h;

5. Pregnancy;

6. Amputation or malformation of any limb or extremity (fingers, leg, or arm) which would impede the placement of sensors, probes, or blood pressure cuffs.

Participants of the Vascular Disease Group will be excluded if they have any of the following:

1. Cigarette/cigar smoking, current or within the last 6 months;
2. Current (within the last 30 days) bacterial, viral or fungal infection;
3. Taking over-the-counter medication within the past 72 h;
4. Pregnancy;
5. Amputation or malformation of any limb or extremity (fingers, leg, or arm) which would impede the placement of sensors, probes, or blood pressure cuffs.
6. Having had a documented previous intervention for CAD or PAD