University of Virginia Health System

New Technology at U.Va. Allows Physicians to More Effectively Treat Heart Disease

We know that 95 percent of patients with heart disease have a cholesterol abnormality, said Dr. Carlos Ayers, professor of medicine and chief of U.Va.'s Vascular Medicine Unit. Yet current cholesterol tests find an abnormality in less than half of all patients. This new system can identify abnormalities that were undetectable with the current method. And a more detailed evaluation allows us to use more targeted therapy. In patients with cholesterol abnormalities, we can now go from reducing heart attacks by 40 percent to reducing them by up to 80 percent.

Cholesterol, a white, fatty substance found in animal tissues, is carried in the blood by lipoproteins, which contain proteins and triglycerides. Too much or the wrong kind of lipoproteins causes plaques to form in the blood vessel wall, which can severely restrict blood flow, causing chest pain. The plaques can also rupture into the artery, causing a clot or heart attack.

Traditional cholesterol-screening panels evaluate a blood sample by using a centrifuge to separate cholesterol into high density lipoproteins (HDL – the good cholesterol) and low density lipoproteins (LDL – the bad cholesterol). The new system, however, uses a centrifuge plus a special analyzer to separate cholesterol into additional fractions: from the lightest lipoproteins, called chylomicrons; to very low density (VLDL); to intermediate density (IDL); to low density (LDL); to Lp(a); and finally to high density (HDL). With this more detailed profile, physicians can use more extensive therapies to target the various abnormalities present.

For example, Ayers said, a traditional lipid screening will detect a problematic LDL, and a drug will be prescribed to lower it. But using the new system for the same patient will detect the problematic LDL plus an abnormal Lp(a), and physicians then can prescribe both the LDL-lowering drug and a drug to improve the Lp(a) level. We can now use multi-drug therapy to dramatically improve the outcome of our patients, Ayers said. We're saving lives.

Aggressive treatment of specific lipid disorders typically involves the use of lipid-modifying drugs combined with dietary modifications and exercise, all of which can stabilize pre-existing coronary artery plaques. In six months, this can drastically reduce the dangers associated with existing coronary artery disease, such as heart attack and death. Ayers said that at U.Va. the new system will be used for patients with known coronary artery disease and for those who have a family history of heart disease.

Other advantages of the new system, known as Vertical Autoprofile (VAP), are that it is faster and more affordable than standard cholesterol screening tests. U.Va. has been using the VAP system for about three years, although a patient's blood sample had to be sent to an Alabama laboratory for the test. With the machine in-house, turnaround time will be cut dramatically.

For more information, call Dr. Carlos Ayers, professor of medicine and chief of U.Va.'s Vascular Medicine Unit, at (804) 924-2765.

December 18, 1998