Your doctor may recommend a carotid intima-media thickness (CIMT) test as a preventive measure for heart disease. A CIMT test measures the thickness of the inner layers of your carotid artery. The carotid artery is the artery that transports blood from your heart to your brain. If you have a thickening of your arteries, known as atherosclerosis, you may not have any noticeable symptoms or warning signs. Instead, plaque can silently and slowly build up in your arteries for years without your knowledge. Often the first symptom a person with heart disease experiences is heart attack or sudden death.
A CIMT test will provide an evaluation of the health of your carotid arteries by identifying changes in the vessel wall thickness and arterial plaques. The state of your carotid arteries correlates to the state of the arteries in the rest of your body, including your heart. If test results show notable aging of arteries, a doctor can prescribe or adjust medications that lower blood pressure and cholesterol, as well as provide nutrition and lifestyle recommendations.
Thicker arteries and plaques can increase your risk of developing the following diseases:
- coronary heart disease (CHD)
- peripheral artery disease (PAD)
- carotid artery disease
- chronic kidney disease
You don’t need to do any special preparation before a CIMT test. Typically, a physician or a medical sonographer will administer the test.
At the start of the test, a gel is applied to your neck. Then the person conducting the test uses an ultrasound probe to record images that can be reviewed later.
CIMT tests usually take about 10 minutes. They are noninvasive, meaning that no blood needs to be drawn or injections made, and they don’t use radiation. You may need to remove some of your clothing for the test.
Following the test, a cardiologist experienced in CIMT will review your images and interpret them. While the CIMT specifically assesses arteries in your neck, the results can provide clues to your overall heart health. Research suggests that there is a strong correlation between plaques in the neck arteries and plaques in the heart.
CIMT tests are used to identify and assess the thickness of the space between the intima and media layers of the artery wall of your carotid artery, which is found in your neck. The measurements are usually in millimeters.
Typically, a doctor will classify the results in one of four categories:
- normal CIMT and no plaque
- abnormal CIMT and no plaque
- normal CIMT test with plaque present
- abnormal CIMT test with plaque present
Then, they’ll use your results and, after also considering other risk factors you may have, provide a treatment plan to help decrease your risk for heart disease.
Your doctor is more likely to order a CIMT test if you have more than one risk factor for heart disease. These include:
- increase in age
- family history of the disease
- high levels of LDL (“bad”) cholesterol, especially VLDL cholesterol
- high levels of triglycerides
- low levels of HDL (“good”) cholesterol
- high blood pressure (hypertension)
- history of smoking
- type 1 or type 2 diabetes
- obesity or being overweight
- inactivity or not exercising enough
Research regarding CIMT tests is somewhat inconsistent. As a result, some cardiologists and other healthcare experts in the American Heart Association believe CIMT tests may be clinically unhelpful in screening for people who don’t have any symptoms. Other research suggests that CIMT might be valuable for getting a more refined perspective on a person’s risk for cardiovascular disease. In fact, a meta-analysis from 2007 found CIMT tests to be a useful tool for predicting future vascular events.
Pros of the CIMT test are as follows:
- It’s noninvasive.
- No blood needs to be drawn.
- It uses ultrasound waves, which are safer than most other waves.
- It’s relatively quick.
- No special preparation is needed.
- It doesn’t impact lifestyle after the test or require any recovery time.
- It provides more data on determining risk.
- Some research backs it up.
Cons of the test include the following:
- It’s not available at all facilities because it’s newer.
- It costs about $250 to $300, and many insurer providers don’t cover it.
- The clinical significance of the test needs more evaluation.
- It may promote excess testing.
- Not all cardiologists are well-trained in interpreting the results of the test.
There are a variety of other tests doctors can use to evaluate your risk of heart disease.
During an electrocardiogram (EKG), your doctor attaches electrode patches to your skin to measure the electrical activity of your heart. An EKG documents heart rhythm and electrical activity of your heart. It’s noninvasive, inexpensive, and easy for doctors to perform. Cons include lack of accuracy, particularly in uncooperative or obese people, and the tendencies to have both false positives and false negatives.
Echocardiography takes images of the heart by using ultrasound. Pros include the ability to visualize your heart valves and heart muscle contractions. Cons include poor quality testing that can occur due to obesity or certain cardiac arrhythmias.
Nuclear cardiology tests
Nuclear cardiology tests are used to take images of your heart using a gamma camera to find out which part is not getting sufficient blood and oxygen. It helps your doctor determine the area of your heart that’s receiving poor blood flow. Usually, a radiographic tracer facilitates the images. The results are often very accurate and provide your doctor with a good idea of what is going on in your arteries, but it may be limited by chest pain and shortness of breath. There can also be false positive and false negative results.
Cardiac CT angiogram
This test allows doctors to take a picture of your heart arteries using contrast dye and a CT scanner. It’s minimally invasive and provides information about the size of and amount of calcium in your arteries, which correlates to the degree of plaque formation. The picture isn’t as good as that obtained through a heart catheter, but it can be helpful in assessing your risk for coronary events. Some people have an allergy to contrast dye. The dye may also injure your kidneys, especially if you have chronic kidney disease.
Left heart catheterization
During this test, your doctor places a catheter in either your femoral artery in your groin or your radial artery in your wrist. Your doctor then moves the catheter through your arteries to your heart and injects contrast dye into your heart arteries to get a picture of any blockages you may have. It’s currently the gold standard test to evaluate your heart arteries. You may have bleeding or hematoma formation at the insertion site. Also, like the CT scan of the heart, the contrast dye may damage your kidneys, especially if you have chronic kidney disease. Some people have an allergy to the dye.
CIMT is a useful test for determining your level of atherosclerosis if you have some risk factors but no symptoms. Your doctors can use the results to help you prevent further damage to your arteries or heart. CIMT is a new test and not covered by many insurers. Additionally, more research needs to be done to understand its clinical effectiveness.
The CIMT test serves as a useful data point to understand the health of your arteries, but you can take steps to improve the health of your heart and arteries:
- Avoid smoking tobacco, marijuana, and other substances.
- Cut down on excessive consumption of alcohol.
- Eat a diet high in proteins, especially vegetable sources such as legumes, beans, and soy.
- Perform moderate to intense aerobic exercise at least three times per week for at least 30 minutes each time.
- Consider resistance exercises, such as weightlifting. Evidence suggests that this optimizes your lipid profile.
- Eat a diet with healthy fats such as polyunsaturated fats, particularly omega-3 fatty acids, and monounsaturated fats.
- Avoid unhealthy fats such as saturated and trans fats.
- Use methods of stress relief such as writing a journal, practicing yoga, or taking a walk.
- Consider talking with your doctor about medications that lower your blood pressure and cholesterol if you have high blood pressure or cholesterol.
- Get a proper amount of sleep. Aim for seven to eight hours of sleep a night.