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Frequently Asked Questions

The following Frequently Asked Questions have been grouped by category for your convenient search and review:

Skin Cholesterol

What is Skin Cholesterol?

Skin cholesterol is the cholesterol that has been deposited and diffused into tissue, as opposed to serum cholesterol which is the cholesterol that is free circulating in the bloodstream.

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What do we know about cholesterol in the skin?

The skin comprises approximately 17% of our total body weight and measures almost 2 metres in surface area. In addition to protecting the internal organs from microorganisms, toxins, and radiation research has revealed that the skin is also directly involved in cholesterol metabolism. In fact, the skin contains approximately 11% of all the cholesterol found in the human body1, and cholesterol synthesis in the skin of mammals accounts for approximately 30% of total body cholesterol synthesis.

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What are the sources of Skin Cholesterol?

The main sources of Skin Cholesterol are epithelial steroidogenesis and cholesterol diffusion from circulation via LDL and SR-B1 receptors, making the epidermis a very active site of lipid synthesis. In fact, it is estimated that 10%-15% of body cholesterol is removed by this cutaneous route, making this elimination channel second only to that involving the liver.

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Why measure Skin Cholesterol?

Elevated Skin Cholesterol levels have been been strongly associated in clinical studies with the presence of serious anatomical coronary artery disease (CAD), making Skin Cholesterol an important new biomarker for risk of CAD. This condition is notoriously difficult to detect and the more information a patient and their healthcare professionals have towards evaluating the true risk of CAD, the greater the chances that preventive measures can be taken earlier to prevent or slow down its progression, leading to the extension and greater quality of one's life.

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How is Skin Cholesterol measured?

Skin Cholesterol is measured by the PreVu Non-Invasive Skin Cholesterol Point of Care (POC) Test, a unique test that has been developed specifically for the purpose of quickly and non-invasively measuring cholesterol levels in the epidermis. Although the test is taken at a moment in time, it can provide a longer-term look at the cholesterol burden in the tissues and a better picture as to how an individual has been historically metabolizing cholesterol over time.

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Is Skin Cholesterol the same as blood serum cholesterol?

No. They each reflect cholesterol in different physiological states. Skin cholesterol is diffused and deposited into tissue, while blood cholesterol is free flowing, fractionated and protein bound. Blood serum cholesterol levels do not correlate to high skin cholesterol scores or vice versa.

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When was the Skin Cholesterol-atherosclerosis link first established?

In the 1970s, the French pathologist Bouissou reported that the skin and the aortic wall undergo very similar morphologic changes during aging and atherogenesis. One of the earliest studies involving Skin Cholesterol examined the relationship between Skin Cholesterol, aortic cholesterol and the extent of atherosclerosis in the aorta based on autopsy findings. This study confirmed the well-known fact that atherosclerotic changes in the aorta progress with age. However, and more importantly, the study also indicated that the changes observed in the aorta were paralleled by changes in cholesterol accumulation in the skin2. Subsequent studies were to follow.

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Is there any more current clinical data available on Skin Cholesterol as a biomarker for risk of CAD?

Recent clinical evidence since 1999 has conclusively demonstrated that high levels of Skin Cholesterol deposits are strongly associated with significant anatomical CAD as measured by treadmill stress test, angiography, carotid intima-media thickness/plaque, coronary calcium, inflammatory markers of vascular disease, previous Myocardial Infarctions and Framingham risk score.

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References:

  1. Sabine, JR (1977) Cholesterol, New York: Marcel Dekkar
  2. Sprecher DL, Goodman SG, Kannampuzha P, et al. Skin tissue cholesterol (Skin Tc) is related to angiographically-defined cardiovascular disease. Atherosclerosis 2003;171:255-58.

Atherosclerosis and Coronary Artery Disease

What is atherosclerosis?

Atherosclerosis is a disease caused by the accumulation of lipids, inflammatory cells and fibrous tissue that thickens and hardens the intima layer of medium and large arteries. Atherosclerotic lesions and plaques are frequently located in areas of arteries under the greatest stress (e.g., side branches, bifurcations, and tortuous vessels). Atherosclerosis can develop in any artery in the body. Atherosclerosis is the leading contributor to CAD.

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What is coronary artery disease?

Coronary artery disease (CAD) is a progressive condition involving formation of atherosclerotic plaques in the coronary arteries. The plaques may gradually impede blood flow through the coronary arteries or they may rupture. CAD may be asymptomatic for many years, but if left untreated, CAD eventually may lead to angina (chest pain), myocardial infarction (MI), or death. CAD is the leading cause of death in Canada.

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What are the risk factors of CAD?

The risk factors for atherosclerosis and CAD are the same. The major risk factors are family history of CAD in a parent or sibling; advancing age; male gender; low levels of HDL cholesterol (HDL-C); elevated levels of total cholesterol, LDL cholesterol (LDL-C), triglycerides; hypertension; diabetes mellitus; smoking; postmenopausal status; abdominal obesity; and sedentary lifestyle.

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Why is the primary prevention of CAD so important?

It is estimated that nine in 10 Canadians have at least one risk factor for heart disease or stroke (smoking, alcohol, physical inactivity, obesity, high blood pressure, high blood cholesterol, diabetes). Having even one risk factor increases a person's chance of developing heart problems and at least 25% of those patients with sudden death or nonfatal myocardial infarction have no prior symptoms1. Primary prevention therefore is critical and requires the identification of higher risk individuals in order to modify their risk factors to prevent new onset CAD.

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For further information on subject matter covered in this section:

References:

  1. Greenland P, Smith SC, Grundy SM. Improving coronary heart disease risk assessment in asymptomatic people: Role of traditional risk factors and non-invasive cardiovascular tests. Circulation 2001;104:1863-67.

Heart Attack/Cardiac Arrest Statistics

What are the heart attack statistics in Canada?

In Canada, there are more than 70,000 heart attacks annually or one event every seven minutes, resulting in over 16,000 deaths.1

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What are the cardiac arrest statistics in Canada?

There are 45,000 cardiac arrests each year (where the heart actually stops) or one every 12 minutes.1 Nearly 85% of cardiac arrests happen in homes or public places with less than 5% of these resulting in survival.1

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For further information on subject matter covered in this section:

References:

  1. Heart and Stroke Foundation of Canada

The PreVu Non-Invasive Skin Cholesterol Point-of-Care (POC) Test

What is the PreVu Non-Invasive Skin Cholesterol Point-of-Care (POC) Test?

The PreVu Non-Invasive Skin Cholesterol Point-of-Care (POC) Test is a unique test that has been developed to quickly and non-invasively measure Skin Cholesterol, providing additive and incremental risk information to help better determine an individual's risk of CAD. The PreVu POC Test is a Canadian developed, completely non-invasive technology that had its conceptual chemistry origins in research conducted in the former Soviet Union and was subsequently developed into a point-of-care assay by doctors, researchers and scientists at McMaster University, Ontario and commercially advanced within the Canadian biotechnology industry.

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What are the characteristics of the PreVu POC Test?

The PreVu POC Test is completely painless, non-invasive, involves no blood draw or needles, requires no overnight fasting and involves no handling of potentially hazardous biomaterials. It is conducted on the palm of the hand in less than 5 minutes with results being immediately available, facilitating point of care consultation within the clinical environment or a next steps discussion out in community healthcare settings.

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How does the PreVu POC Test work?

This simple, yet clinically sophisticated test essentially brings the lab to the patient. The PreVu POC Test uses a Detector reagent that reacts with skin cholesterol on the palm of the hand in proportion to the amount of skin tissue cholesterol on the surface of the epidermis. Another reagent is added (Indicator) and a blue/green colour is allowed to develop in the foam pad well. The color intensity (hue) is then measured objectively by use of the specially designed PreVu Handheld Spectrophotometer. The colour intensity is proportional to the amount of bound skin cholesterol in the palmar surface of the skin.

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What is the PreVu Handheld Spectrophotometer?

The PreVu Handheld Spectrophotometer is a specially designed, highly sophisticated optical reading instrument that not only takes the final hue reading during the PreVu POC Test, but also guides the PreVu Test Operator and updates the patient as well with its LCD display instruction screen through the various stages of the procedure.

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Does the PreVu POC Test generate a number as a result?

The Spectrophotometer produces a numeric result (a colour hue reading) with a range from 50 to 265. This quantitative number is reflective of a patient's risk of CAD based on the elevation of the skin cholesterol biomarker, which would then be taken into account against a full evaluation of a patient's global risk factors for CAD to best determine a course of preventive, intervention or treatment action. These numbers do not relate in any way to the numbers that are traditionally used for measures of serum lipids. Any patient can be evaluated against the continuum of data to see their relative risk against a larger population. However, a skin cholesterol value of 110 has been determined (through clinical study), as the value at which patients acquire an increased burden of risk.1 As skin cholesterol values increase, each 10-unit increase has been shown to augment the burden by an additional 7%.2

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Is the PreVu POC Test a replacement for blood (serum) cholesterol testing?

No. Skin Cholesterol is not the same as serum cholesterol and the PreVu POC Test is not a replacement for serum draw testing. The two measurements do not correlate and are measuring different things - cholesterol in quite different physiological states and places in the body. Both measurements provide important dimensions of understanding and independent risk assessment information related to CAD and should be part of a global risk evaluation of a patient.

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Can the PreVu POC Test be conducted on patients with skin disease?

The PreVu POC Test should not be performed on individuals who are using topical medications, or have skin disease such as eczema or psoriasis on their hands or suffer from palmer hyperhidrosis (a condition characterized by abnormally increased perspiration on the palms).

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How long does the PreVu POC Test take?

The PreVu POC Test test is conducted on the palm of the hand in less than 5 minutes with results being immediately available for consultation and next steps discussion. The test is completely painless, non-invasive, involves no blood draw or needles, requires no overnight fasting and involves no handling of potentially hazardous biomaterials.

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Does a patient need to fast before the PreVu POC Test?

No overnight fasting is required. This is because the skin continuously turns over. Skin Cholesterol accumulates over time. As such, the level of a patient's Skin Cholesterol provides us with a better picture as to how an individual has been historically metabolizing cholesterol over time. It is not unlike the difference in information provided to the diabetic related to blood sugar vs. the longer term view of glycosylated hemoglobin.

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Can the PreVu POC Test be conducted on children?

A pilot study examined the PreVu POC Test methodology in 25 children with hypercholesterolemia, and 25 age and gender matched controls in June 2003. This study found that Skin Cholesterol levels can be reliably measured in children, and these levels do not vary with age or gender, however additional studies in children are needed. Future studies currently being contemplated with larger numbers will determine if there is a significant association between early atherosclerosis development or family history and Skin Cholesterol.

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Do risk reducing behaviours and medicines have an effect on Skin Cholesterol?

There has been some preliminary, independent study work done that presents some interesting data about the impact of certain cholesterol-lowering medications on Skin Cholesterol values. The initial data shows that Skin Cholesterol may be a useful monitoring tool for patients taking statins. Further clinical studies are being contemplated and must be completed to generate additional data to review in this area.

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Does skin colour affect the PreVu POC Test?

No. The PreVu POC Test is conducted on the palm of the hand. Across ethnicity the palm of the hand is essentially the same color and any variation that may be present has been clinically proven not to negatively impact the Skin Cholesterol reading taken by the PreVu Handheld Spectrophotometer.

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Are there any other tests that measure skin cholesterol?

No. The PreVu POC Test is the first and only non-invasive Skin Cholesterol test in the world.

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For further information on subject matter covered in this section:

References:

  1. Stein JH, Tzou WS, DeCara JM, et al. Usefulness of increased skin cholesterol to identify individuals at increased cardiovascular risk (from the Predictor of Advanced Subclinical Atherosclerosis Study). American Journal of Cardiology, 101:986-991
  2. Mancini J, Chan S, Frochlich J, et al. Association of skin cholesterol content, measured by a non-invasive method, with markers of inflammation and Framingham risk prediction. American Journal of Cardiology, 89:1313-1316
  3. PreVu POC Test Operator Training

    Do I need to be trained to conduct the PreVu POC Test?

    Yes. Before testing actual patients, it is the responsibility of all persons conducting the PreVu Non-Invasive Skin Cholesterol Point of Care (POC) Test to ensure they have successfully completed the prescribed training and are qualified to test. PreVu Test Operators must demonstrate that they are able to obtain correct skin cholesterol results, as determined by comparison to established reference values.

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    How is training to conduct the PreVu POC Test accomplished?

    The PreVu Handheld Spectrophotometer comes with a comprehensive User Manual which outlines the testing procedure step-by-step and provides a set of best practice guidelines as well. In addition to this, there is a Training Video CD also included which features a detailed video presentation showing an actual test being conducted with a voice over narrative. This Training Video presentation is also available at www.prevu.com.

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    Do I need to achieve qualification in order to conduct the PreVu POC Test on actual patients?

    Yes. Upon sufficient training and practice the PreVu Test Operator must submit final test data online through www.prevu.com and receive confirmation that they are qualified to conduct the PreVu POC Test on actual patients.

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    PreVu POC Test Applications and Uses

    Is the PreVu POC Test a diagnostic test or a risk assessment test?

    The PreVu POC Test is a risk assessment/odds ratio technology developed to help determine a patient's risk of CAD by measuring epidermal cholesterol, elevated levels of which have been clinically proven to be strongly associated with serious anatomical arterial disease. As a risk assessment test, it has not been developed to replace or substitute any other traditional risk assessment markers or factors. Rather, it has been developed to complement other evaluation techniques by contributing additive and incremental information about a patient's elevated risk of CAD once all the other traditional risk factors have been adjusted for.

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    Can the PreVu POC Test be used as a general screen among asymptomatic individuals out in community healthcare settings?

    Yes, the PreVu POC Test has been designed to serve as a general population screen as a first step in a global risk evaluation process. It can be completed within a few short minutes, is completely non-invasive and painless, and provides instant results for on-the-spot discussion and next-step consultation. Outside of an environment where other CAD testing (including invasive testing such as serum draw) may not be available, the PreVu POC Test is intended to act as both a launch point and a tipping point. In this application it can be leveraged to impress upon individuals the critical importance of following up with their healthcare professional for a full and complete evaluation of all their global risk factors for CAD.

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    Risk Assessment

    Why is Risk Assessment so important?

    The rationale for risk factor assessment is to find patients who are clinically free of coronary artery disease (CAD), but who have sufficiently high cardiovascular risk to warrant more aggressive risk reduction efforts than would first be thought necessary.

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    How do I calculate a patient's risk of developing CAD?

    The Canadian Working Group on Hypercholesterolemia and Other Dyslipidemias, the American Heart Association, as well as the American College of Cardiology have all advocated a determination of 'global risk', as measured by a multifactorial statistical model, such as the Framingham Global Risk Score, to determine a patient's risk of CAD.

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    What is the Framingham Global Risk Score?

    The Framingham Global Assessment tool uses well established cardiac risk factors of age, sex, total serum cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, and smoking status to convert into a 10-year absolute risk for CAD end points estimated from Framingham data. Click here for an online Framingham 10-Year Heart Risk Calculator.

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    Studies and Scientific Research

    What institutions have been involved in Skin Cholesterol research over the years?

    Some of the most important centres of cardiovascular research in the world have been involved in clinical studies related to Skin Cholesterol as a new biomarker for risk of CAD and the PreVu POC Test designed to measure it. These include but are not limited to The University of Wisconsin, School of Medicine and Public Health; The Cleveland Clinic Foundation, Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Bayview Medical Center; The Atherosclerosis Imaging Research Program, Department of Medicine, Section of Cardiovascular Medicine, University of Wisconsin Medical School; and the University of Pennsylvania, Department of Experimental Therapeutics.

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    What medical journals has Skin Cholesterol test data been published in?

    Clinical data in support of elevated Skin Cholesterol measurements as measured by the PreVu POC Test being strongly associated with serious anatomical coronary artery disease have been published in such prestigious peer reviewed journals as The American Journal of Cardiology, The American Heart Journal, Atherosclerosis, and Clinical Chemistry.

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    What medical industry conferences has Skin Cholesterol clinical data been presented at?

    Presentations on the PreVu POC Test and Skin Cholesterol as an additive and incremental biomarker for risk of CAD have been made at some of the most important conferences in the medical and science world including The Annual American Association of Clinical Chemistry Meeting, The American Heart Association Scientific Sessions, The Canadian Cardiovascular Congress, The Annual Scientific Session of the American College of Cardiology, The Endocrine Society Annual Meeting and The American Heart Association Conference on Arteriosclerosis, Thrombosis and Vascular Biology.

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    Regulatory Affairs

    Does the PreVu POC Test have regulatory approval?

    Yes, the PreVu POC Test has been registered and/or received clearance for sale and distribution in a number of regulatory jurisdictions and can be sold in Canada, the United States and within various Member States in the European Union. Regulatory agencies include Health Canada, Therapeutic Products Directorate, Medical Devices Bureau; The Food and Drug Administration, Division of Chemistry and Toxicology Devices, Office of In Vitro Diagnostic Device Evaluation and Safety, Center for Devices and Radiological Health; and the Dutch Health Care Inspectorate (IGZ); Emergo Europe - Authorized Representative, European Union, The Hague, The Netherlands.

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    Medical/Scientific Resources

    What medical and scientific resources are helping advance the PreVu POC Test?

    The PreVu Medical Advisory Board is comprised of leading Canadian and U.S. cardiologists and provides medical and scientific guidance and direction on various matters related to PreVu POC Test. Members include Chair Dr. G. B. John Mancini, MD, FRCPC, FACC (Cardiologist), Founder and Director Cardiovascular Imaging Research Core Laboratory (CIRCL), Vancouver Coastal Health Research Institute - University of British Columbia; Board Member Dr. Henry A. Solomon, MD, FACP, FACC (Cardiologist) Senior Medical Advisor, American College of Cardiology; and Board Member Dr. Milan Gupta, MD, FRCPC, FACC Cardiologist, Scientist & University Professor. Additional scientific resources involved in the advance of the PreVu POC Test include Dr. Michael Evelegh, Ph.D., Immunology (McMaster University), and Dr. Peter Horsewood, Organic Chemistry (McMaster University).

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    Sales and Distribution

    How long has the PreVu POC Test been available on the market?

    The test will become available in Canada for sale in the summer of 2012.

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    How do I order the PreVu POC Test for my medical clinic or pharmacy?

    The PreVu POC Test - which includes the PreVu Handheld Spectrophotometer and the PreVu POC Test Reagent Kit - is exclusively available to the medical community in Canada through The Stevens Company, and to Canadian pharmacies through Pear Healthcare Solutions. Pear is also coordinating turn-key, in-store CAD risk assessment clinics in Pharmacies utilizing the PreVu POC Test.

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