When it comes to determining whether you need to worry about heart disease, you probably take certain assumptions for granted. If you have high cholesterol, a nasty smoking habit, and hypertension, your heart is a ticking time bomb; if you have none of those risk factors, you don't need to worry. Unfortunately, it's not that simple: More than one third of folks who drop dead from heart attacks have none of the classic warning signs. But seeking out a high-tech CT heart scan that peers into your arteries, called cardiac CT angiography, may not be the solution either. A new study published in the Journal of the American Medical Association finds that radiation from the test could raise your cancer risk and that many radiologists aren't taking enough protective measures to reduce radiation exposure.
The results underscore an unsettling reality: There is no perfect way to predict a future heart attack—especially if you don't have heart disease symptoms like chest pain or shortness of breath, or you don't already have established heart disease or its close cousin, diabetes. The risk factors outlined above can be mathematically combined to come up with a predictor of your odds of a heart attack over the next 10 years, called a Framingham risk score, but cardiologist Roger Blumenthal, director of the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, says this assessment is "relatively crude" and frequently misses many men and women of all ages who have dangerous underlying heart disease.
Consider this: Yale University researchers in a study published last month performed CT heart scans on more than 1,600 patients, compared the images of artery plaque with participants' Framingham scores, and found that more than one fifth of the patients who had "low risk" scores actually had enough plaque on their arteries to benefit from low-dose aspirin or cholesterol-lowering statins. "There are many good objections as to why we can't use CT angiography to screen everyone for heart disease," such as cost and radiation exposure, says study author and Yale radiologist Kevin Johnson.
Still, he adds, other imaging tests that use less or no radiation can be very helpful in making treatment decisions. His study also found that more than one fourth of those who were put on statins because of an elevated Framingham risk score actually had perfectly clear arteries and probably didn't need to be on any medications at all. These folks might have benefited, he says, from getting some sort of imaging test before embarking on treatment.
Eventually, the most powerful predictors of heart disease "will come through genetic testing to see not just who is likely to have a heart attack but who is likely to die from one," says heart disease researcher Robert Myerburg, a professor of medicine at the University of Miami School of Medicine. While studies have shown that having a close family member who died suddenly from a first heart attack increases the odds that you will too, scientists are still searching for genetic markers that will tell people for certain whether they need to take aggressive action.
For now, what's the best way to assess your own individual risk? Experts who spoke with U.S. News recommended this seven-step approach:
1. Framingham Risk Assessment: As basic and crude as it may be, it's a good starting point. The assessment takes into account your age, gender, blood pressure, cholesterol, smoking habits, and family history to spit out your risk of having a heart attack in the next 10 years. You can get an estimate of your Framingham score yourself.
2. High Sensitivity C-reactive Protein. This blood test measures a marker for inflammation, thought to be involved in plaque formation. It's often elevated when a person is overweight, out-of-shape, and on the road to diabetes. Many doctors routinely do this blood test nowadays and it can be combined with Framingham risk factors to give you what's known as a Reynolds Risk Score. Research shows it provides more accurate information about heart-disease risk than Framingham and can tell you your heart attack risk out to 40 years and your risk of other heart conditions like strokes. Note: The test isn't accurate for those who already have diabetes, but these folks are already considered to be at high heart disease risk and should be taking a statin.