The European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) have released new consensus-based recommendations on the quantification and testing of atherogenic lipoproteins for monitoring lipid-lowering strategies, which were published in Clinical Chemistry and Laboratory Medicine.

Measuring Atherogenic Lipoproteins

The joint consensus panel of the EAS and EFLM recommends the use of a biomarker or panel of biomarkers for comprehensive testing of atherogenic lipoproteins to evaluate the risk for atherosclerotic cardiovascular disease (ASCVD) associated with circulating low-density lipoprotein (LDL) particles (LDLPs), remnant particles, and lipoprotein(a) [Lp(a)] particles. 

Circulating LDLPs have been associated with a higher risk for atherosclerosis, and should therefore be measured when evaluating the risk for ASCVD. As the cholesterol load in remnant lipoproteins is often higher in the postprandial period than in fasting conditions, non-fasting lipid profiles may be more relevant for the estimation of cardiovascular risk. In addition, it is recommended that Lp(a) and ApoB be measured for ASCVD risk estimation and dyslipidemia characterization only, but not for treatment choice or treatment target.

Standard Lipid Profile

The standard lipid profile (ie, total cholesterol, triglyceride, high-density lipoprotein cholesterol [HDLC], LDL cholesterol [LDLC], and non-HDLC) should remain the main test for the diagnosis and prognosis of ASCVD. The measurement of TC, HDLC, and LDLC is a cost-effective approach to ASCVD diagnosis. From these values, the levels of LDLC and non-HDLC can be derived. When LDLC is measured, RemnantC (ie, cholesterol in remnant particles) may also be measured.

Advanced lipid profiles (ie, with lipoprotein subclasses and apolipoprotein profiles) are used in some laboratories, but studies have yet to assess their clinical value. Minimal lipid profile (ie, total cholesterol and triglyceride only) may be considered in developing countries. 

Fasting vs Nonfasting Blood Samples

Although fasting blood samples have represented the standard for triglyceride measurement, samples taken in a fasting state are not representative of the atherogenic lipid profile observed over 24 hours. Therefore, extended fasting (ie, 8-12 hours) is no longer required for the examination of a lipid profile, with the exception of individuals with a triglyceride concentration ≥4.5 mmol/L in nonfasting conditions.

Recommended LDL Measurements and Calculations

In non-fasting samples, for LDLC concentration <1.8 mmol/L, or for triglyceride concentrations between 2.0 and 4.5 mmol/L, the Martin-Hopkins modified equation can be used to improve the measurement of cLDLC. It is recommended that the “LDL Cholesterol Calculator,” a smartphone application that can provide automated calculation of Martin-Hopkins, based on the patient’s total cholesterol, HDLC, and triglyceride levels, be used.

Direct LDLC assays should be used for the calculation of RemnantC and for the assessment of LDLC when the patient’s triglyceride concentration is ≥4.5 mmol/L (or ≥4.0 mmol/L in some countries).

In patients with known/suspected high Lp(a) concentration or with a poor response to LDL-lowering therapy, Lp(a)-cholesterol correction of measured or calculated LDLC should be performed.

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Using Apolipoprotein B (apoB) to Replace the Standard Lipid Profile

For monitoring the effect of lipid-lowering therapies, the committee does not recommend replacing the standard lipid profile with a single measurement of apoB.

“The consensus-based recommendations of EAS and EFLM provide guidance for the use of contemporary lipid, lipoprotein, and apolipoprotein tests to assist clinicians in their strategies to prevent ASCVD. These recommendations take into account the strengths and weaknesses of the tests in terms of key criteria to become a medically useful test, as defined by the EFLM Test Evaluation Working Group,” concluded the consensus paper authors.

Reference

Langlois MR, Nordestgaard BG, Langsted A, et al; European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Joint Consensus Initiative. Quantifying atherogenic lipoproteins for lipid-lowering strategies: consensus-based recommendations from EAS and EFLM. Clin Chem Lab Med. 2020;58(4):496-517.