A New Tool in Identifying Heart Disease
Heart disease doesn’t play fair. You can jog every morning, stuff your diet with leafy greens, meditate, even control your cholesterol--and still collapse from heart failure well before your 50th birthday. Fully half of all heart attacks strike people whose blood tests are normal, researchers say, so there’s virtually no warning.
That’s why more and more doctors are beginning to consider advanced cholesterol testing for some patients. In recent years, the Food and Drug Administration has approved several techniques that allow doctors to look beyond standard measures of LDL (low-density lipoprotein, or bad) and HDL (high-density lipoprotein, or good) cholesterol and determine more precisely how damaging--or beneficial--those substances really are.
Though the new tests are considered experimental by some, there’s growing evidence that the more refined measures can better pinpoint heart attack risk among people with normal cholesterol readings, doctors say.
“I had no idea I was at risk for heart disease before taking this test,” says Lanse Hyde, a 58-year-old business consultant and competitive distance runner living in Nashville who last April had his blood analyzed by Atherotech, one of a handful of labs doing advanced testing.
Though Hyde’s standard cholesterol readings looked good, his advanced profile prompted further tests that showed evidence of narrowing arteries. Hyde is now taking drugs to lower his LDL levels.
Already, Medicare covers part of the $100 to $300 cost for advanced testing in patients with heart disease. Many insurers also cover the cost. And the marketing opportunity is so great--who wouldn’t want the latest, best cholesterol test?--that doctors already are cautioning that the tests are not for everyone.
“What most worries us now is that this new technology will proliferate into areas where it’s not necessary,” says Dr. Sidney Smith, chief science officer for the American Heart Assn., which has made no recommendations on advanced testing. “We simply need to learn more about” when the tests are beneficial and when they’re not.
Most doctors agree that standard cholesterol screening is a good idea. The standard cholesterol tests measure quantity: A total cholesterol score below 200 is considered desirable, for example, and over 239 is high, a risk factor for heart disease. An LDL score below 100 is considered optimal, and those above 160 are considered high.
The new tests measure, among other traits, the size of cholesterol particles. And size matters, too, in some people. For reasons no one completely understands, men and women whose LDL particles tend to be very small appear to be at higher risk for developing clogged arteries than those whose LDLs tend to be larger. Some doctors call the smaller-molecule profile Pattern B and the larger one Pattern A.
“People with Pattern B have a two to three times greater risk of heart disease than those with Pattern A, as far as we can determine,” says Dr. Ronald Krauss, a UC Berkeley heart disease researcher who pioneered the techniques used by Berkeley Heartlab, another company that does advanced testing.
Krauss says this Pattern A/Pattern B distinction is not significant for people at low risk of heart disease, whose cholesterol is safely below 200.
The same goes for many people who are successfully controlling their cholesterol level by taking drugs: An advanced profile may not alter how they’re treated.
And certainly no one is suggesting that the more sophisticated tests will replace standard cholesterol testing--a much less expensive method.
But cardiologists say there are at least three types of people for whom the new tests could prove helpful:
* Those who have normal cholesterol readings but some evidence of heart disease.
“This is the sort of person who has had chest pains, or even a stroke, or some other evidence of heart disease, and there’s no apparent reason for it,” says Dr. Ronald Saltzman, chairman of the department of medicine at San Clemente Medical Center, who estimates he has sent about 50 patients for advanced testing.
* Heart disease sufferers with high cholesterol who are not responding well to drugs.
“We now have drugs that clearly reduce risk, by 30% to 40% in many people,” says Dr. Noel Bairey Merz, a cardiologist at Cedars-Sinai Medical Center. “But my cardio care unit is filled with people having heart attacks who are taking the drugs. If we can find out something about the quality of their cholesterol, we may be able to help them.”
* People with borderline high cholesterol (200 to 239) who also have a strong risk factor for heart disease, such as family history.
“This is the 42-year-old who comes in and says, ‘My dad died of a heart attack at 43, and I want to know if it’s going to happen to me,”’ Bairey Merz says.
Though it’s not yet clear that the smaller LDL particles actually cause arteries to clog faster, ongoing trials suggest that nudging people from Pattern B to Pattern A can reduce their risk, she says. Losing as little as 5 pounds, for instance, can boost particle size, researchers say.
Daily exercise can help accelerate that shift. And doctors also have a couple of drugs--prescription niacin, for example--that can help people move their pattern from smaller to larger.
“We have evidence now that by combining these therapies with cholesterol-lowering drugs,” Bairey Merz says, “we can get even greater reductions in heart disease risk--60% to 70% in some people.”
If the advanced testing is used responsibly, doctors say, it could also give some people a reason to stop taking cholesterol-lowering drugs. A person with moderately high LDL who has a strong Pattern A profile, for instance, may not benefit much from medication.
Most important, doctors say, is that the test be seen in the context of the patient’s medical history.
“The danger right now is that people will focus on this test as the be-all and end-all, and it’s not,” Krauss says. “You need to consult a physician who is familiar with the test, and who knows how to interpret it. This is not like a blood pressure test; it’s a good deal more complicated.”
