It’s easy for doctors to miss heart disease with basic tests like a cholesterol panel and EKG. These cutting-edge tests may reveal signs of clogged arteries or heart disease symptoms sooner.
by Joel K. Kahn, M.D.
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Advanced cholesterol panel
Picture a highway with 100 passengers. If they are driving 10 to a minivan, there are only 10 large vehicles on the road and it is not too congested. If all 100 are riding in individual small cars, there’s a lot more traffic. That is how large and small LDL cholesterol appears in arteries. Lots of LDL particles clog up the artery highway. Those LDL riders in cars can also be hard and dense, like a golf ball, or large and soft, like a sponge. The small, dense LDL particles do a lot more damage to arteries.
This is why two people with an LDL level of 100 mg/dl can have different heart disease risks, because it’s possible that they have widely different particle numbers and sizes. If someone has fewer than 1,000 LDL particles in a blood sample and they are large in size, their risk for hardening of arteries is low. A second person might have a particle number of 2,000 be loaded with small “golf balls” that are knocking into and entering arteries to cause plaques.
An advanced cholesterol panel blood test can tell you more about your LDL particle number and size.
High-sensitivity C-reactive protein
This is a marker for inflammation, which slowly erodes blood vessels and other organs. In the past decade, a blood test for high-sensitivity C-reactive protein has changed the assessment of patients dramatically. If your hs-CRP is normal (usually less than 0.1 mg/dl), your arteries do not appear inflamed by your diet, lifestyle, or other risk factors. On the other hand, if your hs-CRP is elevated, something is wrong with your lifestyle or health, and we should identify and correct them. I order this exam on every patient at least once a year.
Coronary Artery Calcium Scoring
Tiny amounts of calcium are floating through your blood at this very moment. Just as it hardens your bones, it can also make your blood vessels stiffen. This makes it harder for your heart to pump blood, drives up blood pressure, and makes it more likely that small particles in the blood (like small, dense LDL) stick to the lining of the arteries, setting the stage for dangerous plaque to form.
How it works: A CT scan detects calcium in your heart blood vessels. The ideal score is zero. If your score is between 1 and 10, be very motivated to change your lifestyle. If it’s between 100 and 400+, follow up with a stress test, and make a commitment to change your habits to prevent and reverse this coating of bone in your heart pipes.
Who needs it: The American College of Cardiology strongly recommends this test for anyone with some risk of early heart disease. Because it delivers some radiation, however, hold off until you are 50 or older, unless you have a major heart disease risk factor such as strong family history of early heart disease, smoking, or diabetes. Most insurance companies don’t cover this screening exam, but many hospitals now charge only $100 or less.
Caveat: In addition to radiation exposure, the other limitation is that some artery plaques don’t calcify. That means even if you have a calcium score of zero, you could still have some plaque. There are few plaques like this, however, and these softer plaques generally do not progress to heart disease.
Carotid Intimal Medial Thickness (CIMT)
This test uses an ultrasound machine to see inside the major carotid artery in the neck, which connects the heart to the brain. When it’s diseased, it’s very likely that other arteries in your body are also diseased.
How it works: The ultrasound shows the thickness of the inner two linings of the wall of the artery (called the intima and media). If these walls are getting too thick, it’s a sign of early atherosclerosis. The advantage of CIMT is that it uses ultrasound so there is no radiation risk. If the CIMT is in a normal range (approximately 0.7 mm or less based on age or a thin artery wall), the risk of blockages anywhere else in the body is very low. If the CIMT is 0.8 mm and up, it is time to make over your lifestyle.
Who needs it: This test has received a high recommendation from the American College of Cardiology and there are more than 500 scientific studies that speak to its effectiveness. I recommend it to patients starting at age 50, but even earlier for people who smoke, have high cholesterol, or a family history of vascular disease. CIMT is only covered by some insurance plans. Clinics charge between $150 and $250 on average.
Caveat: While many places own the equipment to do a CIMT, they don’t all have the special software package needed to measure the thickness of the carotid artery and compare it to a normal thickness. Ask if your health care provider will be doing the test with special software dedicated to measuring CIMT.
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Arteries are lined with a single layer of super cells called the endothelium, which keep the vessel resistant to injury and clotting and allow them to dilate to provide more blood flow when needed. Healthy arteries spring back quickly after being squeezed, for example, by a blood pressure cuff. Once the cuff is removed, blood flow doubles, triples, or even quadruples for a few seconds to a few minutes. Diseased arteries don’t do this. When blood vessels don’t spring back, it is a sign of something called endothelial dysfunction, which is one of the earliest signs of artery disease we can detect.
How it works: A blood pressure cuff is placed on an arm and inflated for five minutes, while a special clip is placed on one finger of each hand. When the cuff suddenly releases, the blood flow should increase greatly in the hand of the cuffed arm, but not on the hand that was not. When Mayo Clinic researchers did this test on more than 250 people and tracked their health for six years, those with poor blood flow had a higher risk of heart attack or death.
Who needs it: I recommend EndoPAT for people who just want to know where they stand, but also for those who already know they have heart disease. A patient with a stent who has a normal EndoScore is much healthier than a similar patient with a poor one. The test costs under $200, and it’s covered by most insurance plans.
Caveat: It’s possible to have full-blown heart artery disease (and even to have undergone bypass surgery or stenting) and still have normal endothelial function. This is a good place to be for a heart patient, but it doesn’t mean you should ignore lifestyle changes.
About 40 years ago, an astute doctor observed early artery damage in young children who had an elevated level of an amino acid called homocysteine. More research has shown that in adults, increased levels of homocysteine have also been associated with increased risk of vascular damage. A safe homocysteine level, determined by a blood test, is under 10 micromoles per liter and even better is under 8. I get very concerned when it is in the high teens or over 20 micromoles per liter. Patients with high levels can be treated with B complex vitamins, which is a pretty simple solution.
Lipoprotein-a or Lpa is an inherited form of the LDL cholesterol bound to a special protein. Much research has connected high levels of Lpa to early cardiovascular disease. This is a widely available blood test. I draw it on patients if they have an abnormal calcium score or a thick carotid artery, as well as anyone with any sign of heart disease at a young age. High levels can be treated with niacin, hormone replacement, and vitamins. Most labs indicate a normal Lpa is under 30 mg/dl, but I have seen readings as high as 200 mg/dl. If you test high, consider it an opportunity to incorporate lifestyle changes that will both lower the LDL cholesterol particle number and Lpa level too.
Fasting blood sugar, insulin, and A1c
Any standard blood panel will check your fasting blood sugar. Health care providers may not worry until your blood sugar is in the diabetic range of more than 125 mg/dl, but studies suggest that a fasting blood sugar of less than 85 mg/dl is optimal. Each jump above 85 increases the risk of blood vessel injury.
Blood sugar, however, only presents half of the equation because it is regulated by insulin. If the level of insulin is elevated, the pancreas is working overtime to maintain blood sugar, and the arteries are at risk. I also order a hemoglobin A1c to look at average blood sugar levels over a two- to three-month period. This is a sneaky way of checking for pathologic glycation—or sugar coating—of the hemoglobin molecule. Elevated blood sugar levels not only coat the hemoglobin molecule, but they also coat cholesterol particles, modifying them to become more dangerous.
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A low vitamin D level has been associated with high blood pressure, arterial damage, congestive heart failure, poor brain health, and other important problems. Normally vitamin D is obtained by sunlight and foods such as mushrooms and fortified foods, but even in sunny areas, most people test low. People with dark skin are especially at risk for vitamin D deficiency in the skin. Ask your health care provider to check your level; you want your blood level of vitamin D to be over 30 ng/ml, and optimally, 50 to 80 ng/ml.
Ferritin is a protein in the blood that binds with iron. If ferritin levels are high or low, that means the same is true of iron. Iron overload can oxidize cells in the arteries, leading to heart disease, and can make blood more prone to clotting. Iron overload in the arteries can be checked by a simple blood test for ferritin. Levels above 380 micrograms per liter indicate excess iron. If you test high in ferritin, take care to avoid iron in vitamins and high-iron foods like red meat. Donating blood once a quarter, if possible, can also lower your own iron levels while helping others at the same time.
Uric acid levels and GGT
These two simple and older blood examinations are coming back in use as they provide unique insight to the health of the cardiovascular system. Uric acid is produced from energy products like ATP (the energy used by cells) and an elevated level is linked to cardiovascular damage. GGT is a liver enzyme that may indicate an overall poor functioning of cell membranes in the liver and insight to the overall health of your metabolism. Normal uric acid levels are 4 to 8 mg/dl; levels over 10 are concerning. Normal levels of GGT will fall below 50 IU/L and levels over 100 IU/L are concerning for generalized cell membrane dysfunction.