How Healthy Is Your Heart?
ApoB Test for Precise Heart Testing
You dutifully keep track of your HDL ("good") and LDL ("bad") cholesterol levels, but some experts say this paints only a partial picture of your overall heart health. A new test, called apoB, gives you and your doctor a more precise way of figuring out whether your arteries are in danger of clogging by measuring blood levels of a component of LDL called apolipoprotein B. LDL comes in different-size particles, some large and some small. It's the smallest ones that are most harmful, in part because they're capable of penetrating and lodging in the inner walls of coronary arteries, forming dangerous plaque (whereas large particles "float" on by). Because one molecule of apoB sits on every LDL particle, a high apoB count relative to your LDL cholesterol number would suggest that you have more small, damaging particles than large ones and therefore may be at greater risk of developing heart disease.
"Most physicians haven't tuned in to apoB testing yet," says Ronald M. Krauss, MD, a spokesman for the American Heart Association and director of atherosclerosis research at Children's Hospital Oakland Research Institute, in California, "but an increasing number of cardiologists and endocrinologists view it as a clearer measure than the standard cholesterol test of a patient's heart-attack risk and how she should be treated." Current medical guidelines call for drug therapy to lower LDL to below 100 if you're at high or moderately high risk of heart disease -- that is, if you have a strong family history of heart attack, you smoke, are overweight or have diabetes or metabolic syndrome, a disorder that includes a constellation of risk factors such as high blood lipids, insulin resistance, and excessive abdominal fat. However, your apoB results could prompt your doctor to consider other forms of treatment.Do You Know Your Heart Disease Profile?
For example, if you take two women who each have an LDL of 120 and the same heart-disease profile, a doctor may not recommend medication for patient A if she has mostly large particles, while patient B's mostly small particles might warrant a prescription. "There are probably a lot of women taking cholesterol-lowering statins who don't need them and a lot who should be on these drugs but aren't," says Lewis H. Kuller, MD, chair of epidemiology at the University of Pittsburgh Graduate School of Public Health and a researcher who has studied the relationship between LDL particles and heart attacks in women. In fact, 19 percent of the participants in a 2003 heart study would have a different treatment recommendation if apoB results were used to guide treatment rather than LDL alone.