If you were asked to name some risk factors for cardiovascular disease, chances are you would mention high cholesterol levels. Along with other risk factors such as obesity, smoking, high blood pressure and uncontrolled diabetes, abnormal cholesterol levels is a clear risk factor for cardiovascular disease – especially the kind that’s caused by atherosclerosis or narrowing of the coronary arteries.
According to a report, The Changing Face of Heart Disease and Stroke in Canada 2000, issued by the Heart and Stroke Foundation of Canada, it’s estimated that cardiovascular disease accounts for $7.3 billion (17 per cent) of total direct health care costs in Canada and $12.3 billion (14.5 per cent) of total indirect health care costs for all disease categories.
At least 25 per cent of coronary patients die suddenly or experience a nonfatal myocardial infarction (heart attack) without prior symptoms; so frequent screening with traditional measures has become the recommended method of identifying those at greatest statistical risk so early “preventative” interventions may be implemented. This approach is recommended for both women and men after age 40, when cardiovascular events begin to manifest. Physicians are also beginning to utilize a number of novel risk indicators to help clarify the often ambiguous risk information provided by traditional assessments.
Updated Canadian Recommendations for the Management of Dyslipidemia and the Prevention of Cardiovascular Disease issued in October 2003 stated, “because of the burden of cardiovascular disease and the high rate of death from out-of-hospital acute myocardial infarction, preventive measures are essential in order to reduce health care costs and improve the health of Canadians.”
Link between skin sterol and coronary artery disease With relation to the topic of novel risk markers, researchers have been interested in total skin tissue cholesterol, or skin sterol, for some time, and a number of studies already suggest a relationship between skin sterol and cardiovascular disease. The medical community may soon be able to use skin sterol testing at the point-of-care, as it is quick, painless, does not require any blood, and is highly acceptable to patients.
Estimations of skin sterol levels have become a component of several large research efforts in world-class healthcare institutions and results look very promising. Early data from the University of British Columbia found skin sterol levels correlated to Framingham risk score, and showed a relationship to inflammatory markers. Data from the Johns Hopkins site of the Multi-Ethnic Study of Atherosclerosis (MESA) cohort, presented at the American Heart Association’s Scientific Sessions (November 2003), showed that there is a strong association between the presence of coronary artery calcification (CAC) and the level of skin sterol in Caucasian subjects, independently of serum lipids and lipoproteins. Hence, skin sterol may provide a useful and non-invasive measure of sub-clinical atherosclerosis.
More recently, a new Canadian-US study published in the journal Atherosclerosis (December 2003) provided evidence that skin sterol correlated with the presence of coronary artery disease (CAD) as determined by angiography. Skin sterol was progressively higher as extent of disease increased, and was significantly higher in patients with angiographic disease. Furthermore, the study showed skin sterol is an independent predictor of angiographic disease and remained significantly correlated with disease after adjustment for traditional risk factors individually or combined, e.g. Framingham risk score.
These sorts of results suggest that the new test may provide new information that may assist physicians in the risk stratification of their patients’ cardiovascular health, resulting in a better match of intervention to level of risk.
“Early warning” of risk may encourage preventive measuresWhy is skin sterol testing good news? The new test, used alone or in combination with tests for other risk markers, may give Canadian physicians the tool to further stratify patients, especially moderate risk patients where treatment decisions may not be immediately clear. It is estimated 40% of asymptomatic patients are at moderate risk of developing CAD, and these patients would benefit from further testing in order to better match the intensity of intervention with the level of risk.
This is an important and worthwhile goal. Cardiovascular disease will affect more Canadians than any other illness, particularly those over the age of 50. Heart attack and stroke are still the leading causes of death in Canada.
Prevention is the key, especially since one in every four coronary patients dies suddenly or experiences a non-fatal heart attack without any warning signs. Last year Canadian experts issued updated recommendations for managing dyslipidemia (abnormal cholesterol and other lipids).
“To make an impact on the health of Canadians, physicians must continue to move from a treatment-based approach to a prevention-based approach,” the report stated.
New risk assessment tool would be welcomed Regular screening for risk factors is currently recommended for low-risk patients – both male and female -after age 40.
So far, the skin sterol test has mainly been evaluated in patients considered at high risk for heart disease. Large-scale research is now underway to confirm its usefulness as a risk assessment tool for low-risk populations.
The new skin sterol test, marketed in Canada as PreVu* coronary heart disease predictor, by McNeil Consumer Healthcare, has already been approved for use by Health Canada. It is a non-invasive, painless skin sterol test that does not require fasting. It takes about four minutes to complete and is performed at a diagnostic lab. PreVu* is planned to be available to Canadian physicians in 2004.