Comparison of LDL Particle Count With Other Available Lipid Tests



Status:Unknown status
Conditions:High Cholesterol
Therapuetic Areas:Cardiology / Vascular Diseases
Healthy:No
Age Range:18 - Any
Updated:10/14/2017
Start Date:November 2014
End Date:August 2016
Contact:Eva Stuart, RN
Email:stuart.eva@scrippshealth.org
Phone:858-554-3340

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Comparison of LDL-P With LDLC From VAPII, NMR, and Ion Mobility

Despite the wide availability of advanced lipoprotein tests, no reference standard exists for
Low Density Lipoprotein Cholesterol (LDL-C) due to inherent problems with each of the assays.
Newer methods for estimating LDL particle numbers, including nuclear magnetic resonance (NMR)
spectroscopy and vertical auto profile (VAP) are currently under investigation. NMR has been
proposed as having the best correlation with adverse cardiovascular outcomes. Unfortunately,
the accuracy of LDL-C or LDL particle number measurements is currently not monitored by
national standardization programs. Direct comparisons between the various testing methods
have been limited restricting our ability to accurately interpret and compare values across
vendors and lipid parameters.

Our hypothesis is that:

1. LDL particle count numbers, as determined by NMR (Liposcience), provides the best
estimates of cardiovascular risk.

2. Discrepancies exist between the LDL particle count by NMR and other values as presented
by calculated LDLC and directly measured LDL (VAP and ion mobility).

The investigators will enroll 100 patients recruited from the Lipid Clinic at the Scripps
Center for Integrative Medicine. Each patient will have one blood draw from which four tests
will be analyzed. Risks are associated with drawing blood, which will be minimized by using
Scripps Clinic Lab technicians. The potential loss of personal health information will be
reduced by limiting access to study and lab staff and keeping information password-protected
on Scripps servers.

Introduction Advanced lipoprotein testing has been available for over 50 years and its use in
cardiovascular risk stratification has been proposed in a number of clinical trials (Superko
2009, 2383). Low Density Lipid Cholesterol (LDLC) is currently used as the key cardiovascular
biomarker for assessing risk and monitoring response to lipid therapy (Cole, T. 2013, 752).
The highest correlation with cardiovascular risk has been found with apolipoproteinB (apoB)
or LDL particle concentration by NMR (Brunzell 2008, 814). Despite the wide availability of
advanced lipoprotein tests, no reference standard exists for LDLC due to inherent problems
with each of the assays (Mora 2009, 2402)(Marcovina 2006, 440). The most common laboratory
method of determining LDLC is by precipitation of apolipoproteinB (apoB) containing
lipoprotein particles, measurement of the high density lipoprotein cholesterol (HDLC), and
calculation of the LDLC by the Friedewald equation; however, there are inherent errors
associated with three separate measurements (Marcovina 2006, Superko 2009, 2384). Correlation
between lab LDLC and values obtained by ultracentrifugation has been reported to range from 7
to 31.2%, with a significant amount of misclassification (Marcovina, S. and Packard, C. 2006,
440). Furthermore, elevated triglycerides have been reported to interfere with the accuracy
of LDLC measurements (Marcovina, S. and Packard, C. 2006, 440). ApoB, which is the main
protein component of LDL, is also considered a direct measure of LDL particle number (Cole,
T. 2013, 753). Newer methods for estimating LDL particle number, including NMR and VAP are
currently under investigation. NMR has been proposed as having the best correlation with
adverse cardiovascular outcomes (reference). Unfortunately, the accuracy of LDLC or LDL
particle number measurements is currently not monitored by national standardization programs.
Direct comparisons between the various testing methods have been limited limiting our ability
to accurately interpret and compare values across vendors and lipid parameters.

Hypothesis:

- LDL particle count numbers determined by NMR (Liposcience) provides the best estimates
of cardiovascular risk

- Discrepancies exist between the LDL particle count by NMR and other values:

- Calculated LDLC

- Directly measured LDL (VAP and ion mobility)

Objective:

- To determine the test which has the highest concordance and lowest concordance with the
NMR test Study Design

- Prospective analysis with a target study population of 100 patients

- Superiority study aimed to detect a 300 point difference in LDL particle count

- Requires a one-time lab draw for all patients

Inclusion criteria

- Greater than 18 years of age

- On statin, statin and natural supplements, or natural supplements only

Exclusion criteria

- Within 6 months from an acute myocardial infarction (MI) or acute coronary syndrome
(ACS)

- Non-English speaker

Risks to the patient:

- Loss of personal health information

- Phlebotomy related risks, including injury, bruising, and vasovagal reactions

Inclusion Criteria:

- 18 years of age of older

- Can read and write English

Exclusion Criteria:

- Acute coronary syndrome within 6 months from the time of enrollment
We found this trial at
1
site
La Jolla, California 92037
Principal Investigator: Douglas Triffon, MD
Phone: 858-554-3340
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