Risk Assessment

The rationale for global 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.

Risk assessment for CAD should ideally begin in a clinical environment, where all adults should undergo 'global' CAD screening towards predicting risk under the direction of a healthcare professional, and many do.

However, the reality is that there are many more individuals who fail to access or have access to doctors on a regular basis, if at all, and remain dangerously unaware of the significant risk for a coronary event that they may be living with. These people require access to professional risk assessment and management as well, but need to be approached in a non-traditional manner as a starting point towards moving them into a more formal and clinical risk evaluation process at some near-future point.

The PreVu® Non-Invasive Skin Cholesterol Point of Care (POC) Test has been primarily developed as a risk assessment technology for application in community healthcare settings. As such it serves as a prelude or a first step towards a 'global risk' evaluation to subsequently take place in-clinic, by testing people quickly and conveniently at pharmacies and other public screening venues and focusing their attention on the value of CAD screening. Post-test individuals are advised to visit with their doctor for a more comprehensive evaluation of all their risk factors so that they can become fully aware of their absolute risk of developing CAD. The PreVu POC Test can also be easily employed by healthcare professionals in clinical settings directly, as part of global risk assessment evaluation as well.

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Framingham Global Risk Assessment Tool

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.

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.

Of note, newer risk factors and markers such as Homocysteine, C-reactive Protein, Lipoprotein (a) levels, and Skin Cholesterol are currently not yet included in standard office based tools.

The PreVu POV Test has been developed to uncover hidden, high levels of risk of CAD among individuals by testing for elevated Skin Cholesterol, and to move all who take the test into a global risk assessment process where they can become aware of their absolute risk of CAD based upon a review of all of the risk factors that apply - under the care and direction of their healthcare professional.

The following are traditional risk factors for CAD that are incorporated into a global risk analysis:

Click here for an online Framingham 10-Year Heart Risk Calculator

Once the patient's absolute coronary risk is estimated, appropriate interventions are determined based on their stratification: low risk, intermediate risk, or high risk.

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Low Risk

Low risk patients have a low Framingham risk score and no major CAD risk factors (non-smoking, total cholesterol less than 5.17 mmol/L, high-density lipoprotein cholesterol greater than 1.0 mmol/L, systolic blood pressure less than 120 mmHg, diastolic blood pressure less than 80 mmHg, no evidence of glucose intolerance, body mass index less than 25 kg/m2, and no family history of premature atherosclerotic vascular disease).

Such patients are at low risk (less than 10% 10-year risk) for a cardiovascular disease event in both the short and long term, and may be reassured without further risk assessment testing. They can be offered general healthy lifestyle recommendations, and likely will not require further risk assessments for approximately five years.

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High Risk

At the other end of the risk continuum are patients identified as "high risk." These patients can have established yet asymptomatic CAD, other forms of atherosclerotic disease, or type 2 diabetes mellitus, or may be older with multiple other CAD risk factors, or have extreme elevations of serum cholesterol or blood pressure. These patients have a 10-year risk of a cardiovascular disease event greater than 20%, and should be conceptualized as having CAD or a "CAD risk equivalent." Their cardiac risk factors should be treated aggressively to reduce their total cardiovascular disease risk.

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Intermediate Risk

A large proportion of adults, approximately 40%, fall into an "intermediate risk" category, with a 10-year risk of a cardiovascular disease event ranging from 10% to 20%. As a group, they do not qualify for the most intensive risk factor intervention strategies; however, they have at least one cardiovascular risk factor that exceeds recommended levels. In general, such patients would receive dietary and lifestyle advice, such as the benefits of exercise and smoking cessation, to promote risk reduction. Some intermediate-risk patients may benefit from blood pressure reduction and cholesterol-lowering medications.

However, with intermediate risk patients, healthcare professionals are often left at odds in terms of how best to treat some of them. They don't have enough risk factors present to warrant the kind of aggressive treatment afforded high risk patients, but have a high enough level of risk to rule them out as being treated exactly the way low risk patients would be approached. Many of these intermediate risk patients will go on to have coronary events.

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Further Reading

  1. Genest J, Frohlich J, Fodor G, et al. Recommendations for the management of dyslipidemia and the prevention of cardiovascular disease: summary of the 2003 update. CMAJ 2003;169:921-24.
  2. Greenland P, LaBree L, Azen SP, et al. Coronary artery calcium score combined with Framingham score for risk prediction in asymptomatic individuals. JAMA 2004;291:210-15.
  3. 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.
  4. Pearson TA, Blair SN, Daniels SR, et al. AHA guidelines for primary prevention of cardiovascular disease and stroke: 2002 update. Circulation 2002;106:388-91.

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