Apoprotein B on VAP

We've just received an announcement that, if your Vertical Auto Profile lipoprotein test (Atherotech) is provided through the national Quest laboratories (a large national laboratory company), they will include an apoprotein B.

This represents an improvement over the previous "direct LDL," a measured LDL cholesterol. Recall that standard lipid panels obtained in hospitals and doctors' offices is a calculated LDL, based on the 40-some year old Friedewald calculation. In my view, the Friedewald calculated LDL is a dinosaur that is virtually useless and needs to be retired.

Direct, or measured, LDL is a slight improvement. It removes some of the inaccuracy introduced by the assumptions built into the calculated value.

Apoprotein B (also called apoprotein B100) is yet another improvement. Apo B's have been available for years, but was not provided on the VAP. The Atherotech people have done a good job of making VAP more broadly available through "drawing stations" and proponents like Life Extension. Adding an ApoB is a favorable development, since it incorporates the risk of other ApoB-containing particles, like VLDL, IDL, and Lp(a). Several studies like the Quebec Cardiovascular Study have shown that ApoB is a superior predictor of heart disease compared to calculated LDL.

I still believe that the gold standard for assessing risk from an LDL standpoint is the LDL particle number along with the other measures provided by the NMR assay (Liposcience). However, the addition of the ApoB to VAP adds greater confidence to the measures provided by this technique. Those of you who rely on the VAP assay provided by Quest for your Track Your Plaque program for control of CT heart scan scores therefore have access to this improved panel.

Comments (3) -

  • Marc

    3/20/2008 3:08:00 AM |

    I have great respect for Dr. Davis and I have purchased 3 copies of "Track Your Plaque" (for me, my father, and my uncle who has 4 stents).  I consider Dr. Davis to be very well-informed and cutting-edge, and he does a great job of conveying information in a way that is helpful to healthcare providers and lay people alike.

    This being said, I would like to offer a clarification to Dr. Davis' comments about the VAP test providing ApoB.  (Actually, Dr. Davis was just passing along the claims of Atherotech -- the company that performs the VAP test).

    The Vertical Auto Profile (VAP) test is a cholesterol test.  It provides an indication of lipoprotein particle size, but it CANNOT determine lipoprotein particle concentration (number).

    The only way to measure lipoprotein particle numbers is to measure apolipoproteins (i.e. ApoB and ApoA1) or to use the NMR LipoProfile test (which Dr. Davis correctly considers to be the best test for this purpose).

    What the VAP test now reports is a CALCULATED ApoB value - not a measured ApoB.  

    This is very ironic, because Atherotech has spent the last 10 years telling physicians that they should not trust calculated LDL-C, but now they claim that physicians should order the VAP test to get calculated ApoB (and now calculated ApoA1 as well).

    Unfortunately for Atherotech, their "calculated" ApoB relies almost entirely upon non-HDL-Cholesterol - a value that can be accurately determined by subtracting HDL-Cholesterol from Total Cholesterol on a STANDARD LIPID PANEL (in other words, no need for a fancy, expensive VAP test).

    VAP's ApoB "calculation" does incorporate LDL particle size data, but the inclusion of this data only improved the non-HDL-C correlation with ApoB by 0.5% (ZERO point five percent), so, as I stated, VAP's calculated ApoB relies almost entirely upon non-HDL-C which can be obtained from a standard lipid panel.

    Running a laboratory measurement through an equation in order to express it as a different laboratory measurement does not magically improve its predictive value.  Nor does it remove the limitations inherent in the original laboratory value.

    Correlations exist among all sorts of different laboratory measurements, but we usually MEASURE (not calculate) them individually because we get better predictive value when we look at things directly.

    Atherotech knows that science is leading us away from cholesterol and toward lipoprotein particle numbers.  They are trying to make their VAP Cholesterol test relevant by "calculating" lipoprotein data, but science doesn't work that way.

    After more than a decade on the market, no VAP values (calculated OR measured) have been demonstrated in any clinical outcome study to predict cardiovascular disease risk better than a standard lipid panel.

    I will gladly supply additional information upon request.

    Best Regards,

    Marc W. Garber

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    11/3/2010 2:20:44 PM |

    Direct, or measured, LDL is a slight improvement. It removes some of the inaccuracy introduced by the assumptions built into the calculated value.

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    4/25/2011 3:26:42 PM |

    It is incredible because I didn't know that "Apoprotein B had all those properties, I think it's perfect we receiving this information because we can be aware about it.m10m