Carotid ultrasound: a test for heart disease?

If you wanted to find out whether you had hidden heart disease, just how would you go about it?

Carotid ultrasound is test that some individuals advocate as an indirect means of detecting hidden heart disease. While not perfect, it can be an interesting way to gauge your future potential for heart disease and early enough to take effective preventive action.

Using high-frequency sound, clear images of the carotid arteries (the two arteries on either side of the neck) are available for virtually all people. The carotid arteries are a bit unusual in that they are very close to the surface of the body. Carotid arteries develop atherosclerosis that put us at risk for stroke. But they also provide a gauge of atherosclerosis that could be present elsewhere. That dual role makes ultrasound of the carotid arteries a highly useful test. In particularly, examination of the carotid arteries can provide an index of disease that might be present in the heart's coronary arteries that cause heart attack.*

Carotid ultrasound is easy, safe, and available in most hospitals and even many clinics. No radiation is involved. One difficulty: most insurance companies will not allow you to go through a carotid ultrasound scan as a "screening" procedure, i.e., a test just to see if you have a carotid plaque. They will generally pay (in typical insurance company fashion) if you're having symptoms of a stroke or "mini-stroke" (transient ischemic attack, or "TIA"), have an abnormal sound in your carotid ultrasound detected by your doctor (a carotid "bruit"), or some other unusual indications. Sometimes, a resourceful physician will muster up a diagnosis based on something in your history (e.g., left arm numbness, feeling faint, etc.).

Other options are the mobile scanners and some hospitals that offer carotid screening, usually for a very modest price, usually less than $200 (even occasionally for free) for a combination of carotid ultrasound, ultrasound of the abdominal aorta to screen for aneurysms, and bone density testing. Drawback: Sporadic availability, difficulty in obtaining serial scans, and imprecise reporting since it's viewed as a screening test. But it's a lot better than nothing.

My hope is that, as screening services using safe imaging techniques like ultrasound propagate and increase in direct availability to the public, you'll be able to circumvent the obstacles imposed by your insurance company and even, sometimes, your doctor. But try your doctor first.

I say carotid ultrasound is not perfect because the way it's done in 2008 makes it a non-quantitative test. It is a qualitative test. In other words, you may find out that there's a 30% blockage ("stenosis"), at the far end of the common carotid artery on the right side, but, in truth, that figure is an estimation, given the methods used to measure plaque in the carotid artery (much of which relies on velocity of flow in the arteries). It does, however, suggest several important facts to you and your doctor: First, one or more factors in your lifestyle or genetics allows the development of atherosclerosis. Second, unless you and your doctor take effective preventive action, a stroke could be in your long-term future. Third, coronary atherosclerotic plaque (i.e., coronary disease) is likely present to some degree. Investigating this possibility may be necessary, along with preventive efforts.