Atherosclerosis; Diagnosis

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Atherosclerosis; Diagnosis
May 23, 2006
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The earlier atherosclerosis is diagnosed the better. You'll want to take many of the following steps to determine if you're at risk for this condition. Other steps listed below may be things you want to discuss with your health care professional.

Office-based Physical Exam

All women should undergo an annual exam to assess their risk factors for cardiovascular disease and for any symptoms of atherosclerosis. The physical exam should include measuring your blood pressure and height and weight to calculate a body mass index (BMI). If you have high blood pressure, you should see your health care professional more frequently to make sure your blood pressure is being adequately treated to the goal of less than 120/80. If you're overweight, you have a higher risk of diabetes and metabolic syndrome. Your doctor should encourage you to follow a healthy diet and to exercise regularly to reduce your risk.

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Atherosclerosis; Diagnosis Often, atherosclerosis is not diagnosed until you have complications. However, before you experience complications, your health care professional may be able to hear a blowing sound called a bruit when holding a stethoscope over a damaged artery. Also, you may have a decreased pulse in the affected area. Sometimes, atherosclerosis causes the blood pressure in each of your arms to be significantly different, another symptom your health care professional can easily check.

Laboratory tests

Beginning at age 20, women should have their blood cholesterol checked every five years. A complete lipoprotein level (a blood test that measures total cholesterol, LDL cholesterol, HDL cholesterol and triglyceride levels) is recommended by NHLBI as the initial test to determine if your cholesterol levels are within normal ranges. This type of test, called a fasting lipoprotein test, is taken when you haven't eaten for a prescribed amount of time--usually between nine and 12 hours. Blood-level cholesterol is measured in milligrams per deciliter (mg/dL; a deciliter is one-tenth of a liter).

If you are at risk for high cholesterol or other conditions that contribute to the development of heart disease, your health care professional may recommend more frequent testing.

Here are "at-a-glance" guidelines for your cholesterol levels. Be sure to ask your health care professional if your blood cholesterol goals should be different based on any individual heart disease risks you may have, such as diabetes and high blood pressure, or if you smoke:

Total cholesterol levels:

Desirable: less than 200 mg/dL Borderline high-risk: 200 to 239 mg/dL High risk: 240 and above

HDL (high density lipoprotein) levels:

Optimal: above 60 mg/dL. (Considered protective against heart disease.)40 to 50 mg/dL: the high the level the less your risk for heart disease Less than 40 mg/dL: considered a major risk factor for heart disease

LDL (low-density lipoprotein) levels:

Optimal less than 100 mg/dL Near optimal:100 to 129 mg/dL Borderline high: 130 to 159 mg/dL High: 160 to 189 mg/dL Very high: 190 mg/dL and above

According to NHLBI's updated cholesterol guidelines:

For individuals at very high risk for heart attack, such as those who have had a recent heart attack or unstable angina, LDL cholesterol goals should be less than 70 mg/dL and drug therapy is recommended as an option to reach this goal.

For patients at high risk for heart attack, LDL cholesterol goals should be less than 100 mg/dL, and drug therapy is recommended for individuals with LDL cholesterol levels of 100 to 129 mg/dL. High risk individuals include people with known atherosclerosis (such as those with a prior heart attack, stroke, or peripheral arterial disease), people with diabetes or kidney disease, or people with enough risk factors to give them a 10-year risk of a heart attack of more than 20 percent under the Framingham Risk Score.

For moderately high-risk patients: LDL cholesterol goals should be set for less than 130 mg/dL (or better yet, even less than 100 mg/dL) and drug therapy should be used at LDL levels of 100 to 129 mg/dL to reach this goal. Moderately high-risk individuals include those whose 10-year risk of a heart attack is 10 to 20 percent, those with more than two risk factors for heart disease, those with a positive family history of premature coronary disease or those with the metabolic syndrome.

For low-risk patients, LDL cholesterol goals should be less than 160 mg/dL. Low-risk individuals are those whose 10-year risk of heart disease is less than 10 percent, and who have less than two risk factors for heart disease. Usually, lifestyle changes such as diet and exercise are recommended first, but drug therapy can be added if these are not enough to meet their goal.

Note that lifestyle changes such as diet and exercise are recommended for everyone--even those on drug therapy! When lifestyle changes alone are not adequate, the most common class of medications used to treat high cholesterol is called statins (examples include Lipitor, Zocor, Crestor and Pravachol). Statins are highly effective in reducing cholesterol levels and also reduce the risk of having a first or recurrent heart attack.

Triglyceride (another type of lipid) levels:

Borderline high: 150-199 mg/dL High: 200-499 mg/dL Very high: 500 mg/dL and higher

The goal for triglycerides should be less than 150 mg/dL. If you're at moderate or high risk for heart disease and still have high triglycerides (despite reaching your cholesterol goal with a statin), you may require an additional medication. This includes a fibrate (such as gemfibrozil) or niacin. Fish oil may also help reduce triglyceride levels.

Your doctor may order blood tests other than lipid levels, to determine your risk of heart disease. These include:

Fasting sugar (high levels may mean diabetes or pre-diabetes)

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Kidney function (abnormal kidney function is a risk factor for heart disease)

Homocysteine (high levels are a risk factor for heart disease)

C-Reactive Protein (high levels of CRP suggest inflammation in the body and may be a marker for increased risk of heart disease)

Ankle brachial index

This simple test performed in a health care professional's office screens for peripheral arterial disease (PAD). The blood pressure reading measured in each leg is divided by the average blood pressure reading in both arms. Normally, the blood pressure in the legs is the same or higher than the blood pressure in the arms, so a value of 1 or higher is normal. An ABI of less than 0.9 suggests peripheral arterial disease. Even if you don't have any symptoms, but do have PAD, you should be treated aggressively with medical therapy because you have a higher risk for future cardiovascular events.

There are other tests that can help your health care professional determine if you have atherosclerosis. These are:

Coronary angiography (or arteriography)

This test is used to explore the coronary arteries. A dye is injected into the artery of an arm or leg via a fine tube, or catheter that passes through the aorta into the arteries of your heart. Your heart and blood vessels are then filmed while your heart pumps. The picture that is seen, called an angiogram or arteriogram, shows any blockages caused by atherosclerosis, as well as other problems.

This is the most accurate way to assess the presence and severity of coronary disease. Sometimes this is done in combination with an ultrasound probe which is passed through the catheter down into the coronary arteries. This procedure is called intravascular ultrasound or IVUS. IVUS allows for even better detail of the arterial wall to assess the severity of a lesion and the type of plaque buildup, such as "soft" plaques vs. "hard" plaques.

You may also be injected with a fluid that blocks x-rays, called a "contrast medium" or "dye," which allows getter visibility of certain tissues. The injection may sting and leave a metallic taste in your mouth, a warm or cool sensation at the injection site and in some cases, hives. Many of these dyes are iodine-based, so you need to tell your health care professional if you are allergic to iodine.

If your health care professional decides that you need to have an angiography, you may have to fast four to six hours before the test because of the sedative medications you receive during the test.

If a significant blockage is found during the angiogram, the cardiologist may try to open up the blockage with a balloon with or without a stent--a process called angioplasty.

A CT scan

A computerized tomography scan, or CT scan, sends x-rays through your body at various angles, which are read by a scanner and later compiled and analyzed by a computer. You lie on a narrow table that slides into a tube-shaped scanner and the technician moves the table approximately 1/4 to 1/2 inch after each scan to achieve a cross-sectioned image of the area. Each scan takes only a few seconds, although the entire test may take an hour. You need to remain very still during the test.

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Atherosclerosis; Diagnosis A very fast CT scan called an Electron Beam CT (EBCT) can directly visualize the heart arteries and measure the amount of calcium in the arteries. Since the amount of calcium in the artery directly correlates with the amount of atherosclerotic plaque in the arteries, this can be a non-invasive way for a health care professional to determine if you have atherosclerotic plaque. However, most insurance companies do not cover the cost of this test and this machine is not found at all medical centers.

CT technology is improving, and multidetector CT (MDCT) can get very similar results of the amount of coronary calcium as can EBCT. The MDCT is often performed in combination with CT angiography. This involves injecting dye into a peripheral vein via an IV in the arm and taking pictures of the coronary arteries with the CT scan. It is very similar to the standard coronary angiogram, but is less invasive. Current studies are on-going to compare a CT angiogram with the standard coronary angiogram (called the "gold standard"). Preliminary results suggest that CT angiograms are overall pretty good at detecting blockages, but may miss some blockages in certain cases.

Unfortunately, if a significant blockage is detected on the CT angiography, an individual may still require the standard coronary angiogram and possibly need angioplasty to open the narrowed artery.

Resting EKG

An electrocardiogram may show signs of prior heart damage such as an enlarged heart or areas of prior heart attack. For many women with angina, the ECG at rest is normal. This is not surprising because symptoms of angina occur during stress. Therefore, your heart's functioning may be tested under stress, typically exercise.

Exercise stress test

This test shows how well the heart functions with increased physical activity. An EKG and blood pressure are taken before, during and after the workout. Other stress tests in addition to the ECG use radionucleotide markers such as thallium, or ultrasound (echocardiography), to take pictures of the heart before and after the stress to look for changes in the heart that might suggest blockages. Usually the stress test involves running on a treadmill, but if you can't use the treadmill, the heart can be stressed using medications such as dobutamine or adenosine.

Although the CT scan, EKG and nuclear or echo stress tests may suggest blockages, the blockages can only be confirmed with a contrast coronary angiography.

References

"Implications of the Recent Clinical Trials for the National Cholesterol Education Program Adult Treatment Panel III Guidelines." Circulation: Journal of the American Heart Association. July 13, 2004. http://www.nhlbi.nih.gov. Accessed July 2004.

"What Makes Atherosclerosis More Likely?" National Heart, Lung and Blood Institute. National Institutes of Health. http://www.nhlbi.nih.gov. Accessed September 12, 2004.

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Atherosclerosis; Diagnosis "Update on Cholesterol Guideline: More Intensive Treatment Options for Higher-Risk Patients." NCEP 2004 Update. National Heart, Lung and Blood Institute. National Institutes of Health. NIH News Release. July 12, 2004. http://www.nhlbi.nih.gov. Accessed September 12, 2004.

"Diabetes and Cardiovascular Disease." American Heart Association. http://www.s2mw.com. Accessed September 12, 2004.

"Metabolic Syndrome." American Heart Association. http://www.americanheart.org. Accessed September 12, 2004.

"How is Atherosclerosis Diagnosed?" Diseases and Conditions Index. National Heart, Lung and Blood Institute. National Institutes of Health. http://www.nhlbi.nih.gov. Accessed September 12, 2004.

"DASH Eating Plan." National Heart, Lung and Blood Institute. National Institutes of Health. http://www.nhlbi.nih.gov. Accessed September 12, 2004.

"Cholesterol-Lowering Drugs." American Heart Association. http://www.americanheart.org. Accessed September 14, 2004.

Grady D, Herrington D, Bittner V, et al, for the HERS Research Group. Heart and estrogen/progestin replacement study follow-up (HERS II): Part 1. Cardiovascular outcomes during 6.8 years of hormone therapy. JAMA 2002;288:49-57.

Hulley S, Furberg C, Barrett-Connor E, et al, for the HERS Research Group. Heart and estrogen/progestin replacement study follow-up (HERS II): Part 2. Non-cardiovascular outcomes during 6.8 years of hormone therapy. JAMA 2002;288:58-66.

Writing Group for the Women's Health Initiative Investigators. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women's Health Initiative randomized controlled trial. JAMA 2002; 288:321-333.

"Women's Health Initiative Estrogen-Plus-Progestin Study Media Kit" National Heart, Lung and Blood Institute. National Institutes of Health. Updated July 9, 2002. http://www.nhlbi.nih.gov. Accessed September 12, 2004.

"Women's Health Initiative," National Heart, Lung and Blood Institute. National Institutes of Health. http://www.nhlbi.nih.gov. Accessed September 12, 2004.

"Third Report of the NCEP Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III)." Executive Summary. Journal of the American Medical Association, May 16, 2001. http://www.nhlbi.nih.gov. Accessed September 12, 2004