SPARKS, NEV. — Many patients with “normal” levels of LDL cholesterol go on to develop heart disease. “It is an okay but not great predictor of coronary risk,” Dr. James A. Underberg said at the annual meeting of the American College of Preventive Medicine.
He urged physicians to look at nontraditional biomarkers that offer new insight into coronary risk and the disease process.
With LDL cholesterol, particle size is not a predictor of risk, said Dr. Underberg, president of the New York Preventive Cardiovascular Society. Instead, “particle number is a predictor and is driving the risk in these patients,” he said.
The problem is that LDL cholesterol concentrations often fail to reflect the number of LDL particles and the coronary disease risk associated with them; the number of LDL particles varies widely among patients with similar LDL cholesterol levels. Several treatments are available for lowering the number of LDL particles, including statins, bile acid sequestrants, niacin, fibrates, and cholesterol absorption inhibitors.
“Counseling about dietary and lifestyle changes tends to get lost in the rush of daily practice because it takes time, but I think it's important,” added Dr. Underberg, also of New York University. “Please note that recommended dietary changes should emphasize fiber and plant phytosterols, not just a low-fat, low-cholesterol diet.”
Dr. Underberg also reviewed the importance of lipoprotein (a) as a nontraditional biomarker in cardiovascular risk assessment. It has limited utility as a screening test, but can be a useful measure in patients with a family history of premature coronary disease.
When other risk factors are at an intermediate level, lipoprotein (a) can be useful in deciding how aggressively to treat. Once it has been tested, there is no need to repeat the measurement because it doesn't vary greatly over time.
The high-sensitivity C-reactive protein (CRP) test is another nontraditional but valuable method for assessing cardiovascular risk. CRP is involved in a variety of processes, and probably plays a role in the development of atherosclerosis.
CRP helps to predict coronary risk, and can be used as a prognostic indicator in acute MI. CRP levels do fluctuate, so it is reasonable to repeat this test after 2–3 weeks. For example, CRP levels rise in various inflammatory conditions including acute illness and viral infection, and after dental work.
Physicians should be more aggressive when considering statin use in younger women whose risk justifies use of these drugs. The Food and Drug Administration requires a “do not use if you are pregnant or breast-feeding” label on prescription statins because of concerns about teratogenic effects. “Many younger women at high risk for cardiac problems are undertreated,” Dr. Underberg said.
“Many older women are not counseled about pregnancy risk when using statins, and they should be because they may still be considering childbearing,” he added.
He encouraged physicians to discuss this issue with their patients. In order to treat a younger, high-risk, sexually active woman with statins, consider informed consent and an agreement about use of birth control. If her plans change, the woman should stop using statins 2–3 months before stopping birth control. Consider hydrophilic statins (pravastatin and rosuvastatin) for use in women of childbearing age, since these drugs are less likely to pass the blood-placenta barrier.
Dr. Underberg is on the speakers' bureau and/or receives research funding or consulting fees from Pfizer Inc., AstraZeneca, Sankyo Co., LipoScience Inc., DiaDexus Inc., and Forest Laboratories Inc.