Articles by Dr. Whitney
 

Heart Disease- Stress Tests and Coronary Calcium Scoring
Articles by Dr. Whitney >> Newsletters

Heart disease is the #1 cause of death in both men and women in the United States. Coronary artery disease occurs when plaque develops in the arteries that wrap around our heart to supply it oxygen. A plaque blocking the flow of blood may require cardiac procedures like stents to bridge the obstruction, possibly bypass surgery.

Intuitively it would seem that opening these blockages with procedures would lower our risk of heart attack. However, recent studies have shown that procedures performed on some plaques may actually increase our risk. Aggressive risk factor treatment is often better.

Stress Test as a Screen for Heart Disease

Stress tests have historically been used to screen for significant coronary plaques. However, it is false reassurance to think that a normal stress test means no problems are looming. Only a plaque large enough to block 50-70% of the artery causes a stress test to be abnormal. However, even a much smaller plaque may rupture, form a clot, and completely block the artery. Complete blockage causes a heart attack. This is what happened to Tim Russert. He had a normal stress test 6 weeks before a plaque rupture asphyxiated the electrical center of his heart, causing sudden death.

Plaques of any size can rupture. We don't know of a way to reduce plaque, so our goal is to stabilize plaque that is already present through optimal nutrition, physical activity, and even dental care. I will review these risk reduction methods in future newsletters and individually during the cardiovascular health assessment of your wellness evaluation.

Stress tests are over-utilized and place many people having one at higher risk than if no testing is done. When a stress test is abnormal, a cardiac catheterization is required. Catheterization carries a 1% risk of major complication. In a low risk person, an abnormal stress test is most likely a false positive, meaning that nothing is wrong despite the abnormal test. Risk of the catheterization needed to prove a false positive stress test far exceeds the value of a stress test in a low risk person. Don't misunderstand what I am saying. Stress tests absolutely have their role in medicine and I frequently order them. However, a newer technology is available that enables us to find evidence of developing cardiac plaque much sooner than a stress test would. It is called coronary calcium scoring.

Humans are born with no calcium in our coronary arteries. Calcium gets pulled into plaques along with cholesterol. The amount of calcium present in the walls of the artery reflects the overall amount of plaque present. Calcium can be measured by an x-ray from which computer software calculates a coronary calcium score. The test's price has dropped to as low as $125 and some insurances are beginning to pay for it, finally recognizing its value.

Consider a 46-year-old with low grade hypertension, mildly elevated cholesterol, and a family history of heart disease. He is at fairly low risk and almost certainly will have a normal stress test. There are reasons why this person may need a stress test, but for most, a coronary calcium score would be much more beneficial.

If the patient's calcium score is zero, it is reassuring that no damage has been done. High blood pressure and cholesterol would be treated with lifestyle changes only, not medication. The presence of calcium suggests plaque and warrants more aggressive treatment with medication and maximal lifestyle changes. I'm sure you can imagine the motivation an elevated calcium score gives a person to make needed changes. Eating properly and exercising usually become much easier!

The test is painless. It literally takes just a few seconds, involves no needles, and you don't need to disrobe. There is a small amount of radiation exposure during the test, but I feel this is worth the value of assessing the calcium score in the right person.

The bottom line is that cardiovascular disease risk assessment and treatment need to be tailored to the individual. Advances in cardiology have changed our understanding and approach significantly over the past two decades. There is no longer a cookie cutter approach to our management of cardiac risk factors. Management is based on excellent research and technologies now available.

Last changed: Jun 05 2009 at 1:10 PM