Q: What is the difference between the VAP Cholesterol Test and the routine lipid panel?
The VAP Test provides all the information found in a routine lipid panel, plus measurements of all known cholesterol subclasses that play an important role in the development of CAD. The additional information provided by the VAP Test improves the ability to predict heart disease risk to a far greater number of patients.
The routine cholesterol test detects only about 40% of people at risk. In contrast to the routine lipid panel, the VAP directly measures LDL cholesterol and all other lipid risk factors to detect greater numbers of patients who are at risk for heart disease and diabetes.
Q: Why is a direct measurement of LDL cholesterol important?
A: The NCEP ATP III recommends that LDL cholesterol be directly measured independent of a patient’s fasting status. Currently, the LDL cholesterol is not directly measured using the routine lipid panel. Rather, it is estimated using the Friedewald equation: [LDL] = [total cholesterol] – [HDL] – [triglycerides/5]. Thus, estimated LDL cholesterol levels are falsely low in patients with elevated triglycerides, and it does not correlate well in patients with diabetes, coronary disease, or other atherosclerotic diseases.
Q: How can the VAP Test help customize patient treatment?
A: The availability of more sophisticated cholesterol treatments points to broader use of the VAP Test because results will help physicians more specifically match a drug or combination of drugs with a patient’s cholesterol profile. The VAP Test’s breakdown of lipid subfractions is vital in determining appropriate treatments. For example, elevated IDL doubles the risk for CAD and requires a statin plus niacin in combination. Lp(a) is 10 times more atherogenic than LDL cholesterol on a mg-for-mg basis and requires niacin. For more information, download Using VAP Expanded Lipid Testing to Develop Optimal Patient Treatment Plans by lipid expert Paul Ziajka, M.D., Ph.D.
Q: What is meant by "emerging risk factors" for heart disease?
A: The NCEP ATP III guidelines discuss a number of emerging risk factors for heart disease, including small, dense LDL and lipoprotein "a" (Lp(a)), and triglyceride rich remnant lipoproteins. LDL is not present in the circulation as one well-defined structure; rather it is present as a continuum of size and density. The presence of small, dense LDL quadruples the risk of heart disease compared with the same total LDL concentration present in a large, buoyant form. Lp(a) is a genetic risk factor that has been shown to be 10 times more atherogenic than LDL on a mg per deciliter basis. Thus, it is important to measure Lp(a) in patients with a family history of premature atherosclerosis. Importantly, these emerging risk factors are not measured by the routine lipid panel.
Q: Can the VAP Test detect the metabolic syndrome?
A: The "atherogenic lipid triad" of low HDL, high triglycerides, and small, dense LDL frequently present in patients with metabolic syndrome—is described in NCEP ATP III guidelines as a widespread and under diagnosed health problem.
Q: Do the NCEP guidelines point to the use of an expanded lipid panel like the VAP Test?
A: The NCEP ATP III guidelines offer new opportunities to improve the early detection and treatment of heart disease. ATP III focuses attention on the metabolic syndrome, as well as several emerging risk factors and secondary targets of therapy that are not measured with the routine lipid panel. The VAP Test allows clinicians to comply with ATP III at a cost comparable to the routine lipid panel.
Q: Are VAP Test results accurate?
A: Yes. The VAP Test is based on ultracentrifugation, the gold standard for reference lab lipid measurement. The test is processed at Atherotech’s CLIA-approved diagnostic laboratory. In addition, Atherotech has the accuracy of the VAP Test confirmed by two highly recognized lipid standardization programs—the Core Laboratory for Clinical Studies at Washington University, St. Louis, MO, and Proficiency Testing Program by NY State Department of Health.
Q: Is the VAP Test cost-effective?
A: The VAP Test costs about the same as the routine cholesterol test and is reimbursed by most insurance carriers. It is more cost-effective than running the several tests needed by other labs to report what a single VAP Test will report.
Q: Is the VAP test covered by insurance?
A: VAP test is reimbursed by Medicare, Medicaid and many other health insurance plans.
Q: How can I incorporate the VAP Test into my practice?
From sample collection and shipping to billing and customer support, integrating the VAP Test into your practice is easy. All necessary items, including express shipment packaging and prepaid airbills, are supplied. A standard 5 ml venous blood draw is the required sample, which is then forwarded to Atherotech’s state-of-the-art reference laboratory for processing. The comprehensive results are generally provided within 72 hours via fax or secure website.
Q: How accurate is the apoB data in determining risk compared with the gold standard?
A: Atherotech has developed a novel procedure to report apoB utilizing non-HDL cholesterol along with lipoprotein density distribution using the patented VAP ultracentrifugation method. Atherotech has thoroughly validated this new procedure by comparing its apoB with the standard* using serum from 1,797 patients. This comparison has yielded an excellent correlation coefficient (r = 0.97) with bias of only 0.8%. The long—term (40 days) reproducibility of VAP apoB is 3.0% CV (coefficient of variance). The VAP apoB work was accepted through a peer review process for presentation at the 2007 Annual Meeting of American Association of Clinical Chemistry (AACC), and was subsequently published by AACC as an abstract.
* apoB immunoassay provided by Abbott Diagnostics; calibrated against
WHO/IFCC/CDC Apolipoprotein Reference Material
Q: What percentage of patients would have been mismanaged if treatment was based solely on standard testing?
A: To answer this with actual test results Atherotech pulled test data from the second half of 2007 for which Atherotech performed both Standard Lipid Panel (SLP) testing and the VAP Test. There were 4,862 such specimens. These were not subject to any sampling or filtering criteria. Our findings:
- 904 (19%) patients had a estimated LDL using the Friedewald equation that was more than 10% lower than the directly measured LDL from the VAP. These underestimated LDL values from SLP represent patient risk that would have gone undetected without VAP testing.
- 2,866 (59%) patients had emerging risk factors present that could lead to reducing the target LDL by an additional 30 mg/dl, based on ATP III recommendations. This would likely lead to more aggressive treatment to mitigate the presence of these risk factors. None of these risk factors can be obtained using SLP.
- 493 (10%) patients had atherogenic dyslipoproteinemia, characterized by the combined presence of small dense LDL, low HDL, and elevated triglycerides. ATP III recommends intensive therapeutic lifestyle changes and possibility for nicotinic acid for this risk combination, rather than statin treatment alone. This diagnosis and treatment strategy would be missed using SLP alone, since it does not provide information about LDL density.
In total, 3,100 (64%) patients had one or more of these findings that would lead to more accurate risk identification and/or different therapeutic treatment than would occur using "standard testing" (SLP).