Home / Archive / Men's Health: Evaluating Heart Health
Saturday, February 04, 2012
Special Report: February 2006
Evaluating Heart Health
A new test can predict heart attacks, but it can also confuse its takers
Story by Judith Horstman
Let’s face it: If you are male and 45 or older, the word you are most likely to think of when people say “heart” isn’t romance — it’s disease. Or maybe attack.
With good reason: The first symptom of heart disease, the No. 1 killer of men since 1900, for 150,000 people every year is a fatal heart attack.
There’s no perfect early-warning system yet, but there is a screening test making the rounds that may predict the risk of an attack in some people. It’s called a computerized tomography cardiac calcium scan, a non-invasive imaging test that can show arteriosclerosis, or hard plaque buildup in the arteries. And you don’t need a doctor’s prescription to get one.
There’s disagreement among cardiologists about just how much this test helps to evaluate your total heart health. But Burton Stanley, 65, a retired Sacramento environmental lawyer, is a believer.
Stanley weighs as much as he did in high school; he bikes, walks and skis; and he has low cholesterol and blood pressure. His only risk factor is a family history of heart attacks. A few years ago, he started having chest pains off and on. He says his doctors weren’t concerned, but he was.
When he heard about the CT cardiac calcium scan, he took matters into his own hands and went to get one. “And the technician said, ‘You’re 95 percent blocked and I think you should do something about it.’”
A cardiologist a friend recommended told him, “Go to the ER right away. Don’t wait.” By the end of that day, he had had an angioplasty and three stents.
“They said my heart attack had already started to happen when they began the angioplasty, and that I was within 45 minutes of a blockage,” Stanley says.
That was two years ago, and he is feeling better than ever. He says he considers the screening essential. “I’ve recommended it to all my friends, and a lot of them have had it,” he says.
Stanley is a textbook example of the person experts say could benefit from a cardiac calcium screening: someone with no symptoms (or ambiguous symptoms) of heart disease, but risk factors such as a family history of heart problems, high blood pressure or diabetes.
But in spite of this happy outcome, not all doctors think heart scanning as a screening test for heart disease is a good idea. And insurance may not cover it.
Here’s how it works: The CT calcium scan is painless, quick and relatively cheap (between $200 and $350.) There are no injections.
The non-invasive scan process takes 15 to 20 minutes total, from getting ready for the scan to leaving the tech room. Of that, five to seven minutes are spent in the open-doughnut scanner, and there are 18 to 20 seconds of radiation exposure. That exposure is equal to about 10 chest X-rays. At least three Sacramento radiology groups offer the test on a walk-in, self-referred basis.
The scan identifies calcium plaque, which almost always accompanies cholesterol plaque, says Dennis Breen, M.D., a cardiologist and partner in Sacramento Heart and Vascular Medical Associates.
Cholesterol in your arteries doesn’t show up on X-rays or other external imaging very well, as it is similar in density to surrounding tissues, he says. “Calcium is noticeably different in its density: It stands out like white chunks, like snow in a stream.”
The amount — or lack — of calcium can predict your risk of atherosclerosis, the term for fatty deposits that can lead to arteriosclerosis, or hardening of the arteries. In general, if you have a lot of calcium plaque, it is likely you have some amount of atherosclerosis.
In a recent study, researchers gave the CT scan to about 2,000 Army personnel between the ages of 40 and 50, mostly men undergoing routine physicals. Over three years of follow-up, nine of the men had a heart event — seven of them from the group whose CT scans had shown calcium deposits.
That translates to a risk of heart event 11.8 times greater for those with calcium deposits than for those with no detectable deposits, according to an American College of Cardiology press release — “and these were men who didn’t have a lot of risk factors and were in their mid-40s, at a time when people are at the prime of their work and family lives,” says Col. Allen J. Taylor, M.D., chief cardiologist at the Walter Reed Army Medical Center and lead researcher on the study.
Taylor, who has completed some 20 studies of CT scans, says the test is beginning to be included in guidelines from heart organizations, including the National Cholesterol Education Program, and may be covered by more health insurers this year.
But the test has limits, say other experts. A zero-calcium score means you have no detectable calcified hard plaque buildup, but doesn’t mean you have no heart disease.
Remember, this imaging test is only looking at the amount of calcified hard plaque inside the arteries, says John Micheels, the imaging centers’ operations manager at the Sacramento Radiology Medical Group.
“It won't visualize soft plaque, identify stenosis [narrowing] of the vessel or tell you anything with regard to cardiac function,” he says. “Its sole purpose is to screen for calcified plaque. If it’s not calcified, we’re not going to see it.”
Also, the scan can generate misleading conclusions about the amount and placement of plaque and its potential effect, says Lawrence J. Laslett, M.D., a UC Davis cardiologist and professor of medicine who is skeptical about the value of the test.
“Patients need to be prepared for the result.
If it’s abnormal, there’s a lot of psychological stress.”
— Jason Rogers, cardiologist
It can detect atherosclerosis, he says, “but not necessarily the narrowing of an artery, since the added bulk of the plaque may expand it. So you could have a lot of plaque and not have any narrowing — or you can have significant narrowing that’s not calcified.”
The calcium scan is not nearly as accurate as an angiography, in which a catheter is threaded through a blood vessel in the groin up to the heart, where contrast dye is injected for X-ray images of the arterial lining.
There are some false positives, says Breen. “Telling someone they have calcium in their coronary arteries can be upsetting, and there isn’t any guarantee that it means a life-threatening amount of plaque. It might unduly alarm people, when it’s a relative indicator, rather like economic indicators.”
Once the genie is out of the bottle, you may find yourself caught up in a series of tests, as doctors today don’t want to be accused of ignoring test findings.
That means people who may not need treatment might get an unnecessary angiogram, which tells more but involves some risk and much more radiation than the CT screening, says Patrick Vogel, M.D., a vascular radiologist with Radiological Associates of Sacramento.
“My experience is the ‘worried well’ will worry even more if they have the test,” says Laslett.
“Unfortunately, the ‘worried well’ don’t stop worrying,” agrees Vogel, “and they frequently worry their doctors till they end up on the heart cath table. These are not decisions for an individual to make alone — they need to make them with their doctor.”
“They need to be seeing their doctors,” says Jason Rogers, M.D., a cardiologist at the UC Davis Medical Center. “A heart scan is a screening test, and patients need to be prepared for the result. If it’s abnormal, there’s a lot of psychological stress.”
If you have not been taking care of yourself and results show a bit more calcium than is considered optimum, it could be the impetus that gets you to improve your heart health. There’s no way to make arterial plaque go away, but with medication and lifestyle changes, you can prevent further progression. If you are health-conscious, pretty good test results can reinforce your good habits.
Bob McCafferty has made it a mission to stay fit since he stopped smoking years ago. At age 68, he has had no symptoms of heart disease. He watches his cholesterol levels, walks, works out, tries to eat well and manage his stress levels — none of which is easy for someone working in public relations in the state Department of Aging.
Still, a history of heart disease in his family was nagging at him. “My dad died at 62 of myocardial infarction,” he says. And McCafferty had a long career in the stress-saturated field of journalism, where, he says, “We used to joke we lived on coffee and cigarettes.”
So three years ago, when his doctor suggested he pay out of pocket for a CT cardiac calcium screening, he was all for it — and relieved to see it showed only a modest amount of calcium. The results increased his already strong dedication to healthy living.
When he had his annual checkup this fall, all of his heart-health indicators were right on target. “That was such good news,” says McCafferty. “So, based on his advice, I’m not going to get another scan this year.”
The bottom line: A CT cardiac calcium scan can yield important information about your risk of atherosclerosis. But that complex information is not easy to understand.
“Test interpretation is difficult,” says Taylor. “It depends on your gender, ethnicity, age and your risk factors.”
“Talk to your doctor before you spend a lot of money and expose yourself to a lot of radiation,” says Laslett.
The formerly preferred method for cardiac calcium scans, an electron beam imaging machine, has pretty much been replaced by new CT scanners, which have evolved from a single-slice image to today’s eight-, 16- and even 64-slice machines.
The more slices, the more detail, and the new CT scanners, which produce remarkable images, are becoming the norm, says John Boone, a medical physicist and professor of biomedical engineering at UC Davis.
For those who have symptoms of heart disease, there’s a CT coronary angiography (known as a CTA) to assess the extent and help determine treatment. It is not a screening test — it’s for people who already have some strong indications or even a diagnosis of heart disease.
While the traditional invasive angiogram remains the gold standard, the CTA version allows doctors to examine arteries without the small risk involved in threading a catheter or other invasive device into the heart. A contrast dye material is injected and a CTA scan follows the dye outlining the interior of the arteries. It shows deposits, blockages and details about the walls, especially the amount of calcium plaque.
Vogel says if there is reason to suspect heart disease, it’s time to skip the CT scan and go to a CTA. It emits 10 times the radiation, and some people have reactions to the dye, but it gives three times the information and is more accurate.
It is offered at local imaging centers and may be covered by your insurance, but requires a doctor’s orders.
Newer yet is color-coded virtual histology, an invasive imaging process that produces detailed, color-coded images of different plaque, enabling doctors to spot the most likely areas for trouble. It is used along with a catheter that is threaded into the heart.
This examination is done on people doctors know have some amount of heart disease.
“You’re plugged and you know it,” says Rogers, who is using the technique in research.
Under development by Volcano Therapeutics Corp. in Rancho Cordova, the new virtual histology technology detects four types of plaque and color-codes images of the types by density.
Identifying areas of vulnerable plaque — plaque that is most likely to burst and lead to a heart attack — may help doctors identify the trouble areas in which to put stents to prop open arteries, says Rogers.
To scan or not to scan: facts at a glance
What does a CT cardiac calcium scan cost? Between $200 and $350 at area imaging centers, usually not covered by insurance.
What does it show? Calcium deposits in the arteries. The higher the calcium score, the more likely that there is atherosclerosis, fatty deposits in the arteries that can cause heart disease. The test does not show artery narrowing, other kinds of plaque, heart disease or heart function.
What are the risks? A CT scan is painless, non-invasive and generally regarded as low-risk. It gives a dose of radiation about equal to that from 10 chest X-rays. It can produce misleading data that could lead to more tests, especially invasive tests that may not be necessary.
Who might benefit from a screening test? Someone who has at least one risk factor, such as a family history of heart disease or high cholesterol or blood pressure. Someone who does not yet have a diagnosis of heart disease, as this is a screening test for disease markers. If you have already been diagnosed with heart disease, it is not needed.
Who should not have a CT calcium scan? A man younger than age 40 and women who are pre-menopausal, unless ordered by a doctor because of high risk factors. African-Americans, as there is not enough data yet to understand what the test means for this group. Anyone who has symptoms or a diagnosis of heart disease, or who has had heart surgery; more-detailed diagnostic tests are needed in these cases.
Talk to your doctor if you are considering this or any other screening test.
