Testing for Heart Disease

Doctors Screening for Heart Disease

Dr. William Davis Health Pro May 05, 2009
  • You walk into your doctor's office. Rather than a white coat, he is wearing flowing sorcerer's robes, crouched over a crystal ball attempting to divine your future.

     

    Ever happen to you? I hope not.

     

    Then why do we rely on our doctors to divine our heart health futures? It's no different than reading tea leaves or charting the configurations of the planets to judge health.

     

    How does your doctor predict your heart health future? Rather than a crystal ball, he or she looks at risk factors for heart disease: smoking, LDL cholesterol, whether or not you're diabetic or have high blood pressure, your family history. Some gauge of risk is then formulated: high, low, intermediate. Following the above approach, the vast majority of the U.S. adult population falls into the "intermediate risk" category, i.e., neither high nor low risk for heart disease.

     

    But does this really help you? If, for instance, you are informed that you are at "intermediate risk," do you really know whether you are going to have a heart attack in 3 months . . .  or not?

     

    No, you do not. In fact, the majority of future heart attacks occur in the intermediate risk group, simply because it is a larger group.

     

    If you are at low risk, does that mean you are immune? No, it simply means that the likelihood of heart attack or death from heart attack is less than 1 in 10 over the next 10 years. Does that sound like low risk to you? High risk, of course, is worse: 20% or greater risk over the next 10 years.

     

    To illustrate, let's take a hypothetical, though common, example: Joe, a 50-year old, slightly overweight man. He exercises twice a week, but feels well during racquetball and walks with his wife. His blood pressure was just a bit too high on his last doctor visit. His cholesterol was also "a little on the high side," according to his doctor. He is a non-smoker and his father had a heart attack later in life at age 76. Can you tell if Joe has heart disease?

     

    I can't and neither can your doctor. Sure, we could enter the numbers into a risk calculator and come out with something like "10% risk for coronary events over the next decade."

     

    The truth is that these sorts of risk scoring approaches are virtually useless to help determine whether or not heart disease is present or not in a specific individual. Risk factors cannot tell you whether heart attack could interrupt your football game this Sunday, whether you are destined for a bypass operation in two years, or whether you will live until age 95 still dancing the Hustle.

     

    We are thankfully leaving the age of shaky risk prediction and entering the age of disease measurement. For coronary heart disease, this means we need to look for the earliest evidence of coronary atherosclerotic plaque. If you have it, you have the beginnings of the disease and an intensive effort at prevention should begin. If you don't have it, then there will be no real risk for heart disease for many years and an intensive prevention effort is not required.

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    For all the hype and controversy that has surrounded the application of CT scans for heart disease detection, simple, low-radiation CT heart scans remain the only way in 2009 that early coronary atherosclerotic plaque can be detected. (CT coronary angiography, often mistakenly called "heart scans" by uninformed media, are the high-radiation tests that have stirred controversy. This test should not be used for screening purposes like I am discussing. CT coronary angiography is a diagnostic test that helps answer specific questions, not a screening or prevention tool.)

     

    Perhaps in 10 years we will have some easier, more accessible way to detect and measure coronary atherosclerotic plaque. Who knows, maybe we may even have a do-it-yourself-at-home test? But, until that time, CT heart scans remain the only way to confidently gauge not just risk for heart attack, but heart disease itself.

     

    Or, you could ask your doctor if he reads Tarot cards.