Abstract 18619: All Advanced Lipid Tests are Not Equal: Prospective Analysis of Discordance Between LDL-P, Small Dense LDL (or Subfractions), and HDL-P (or Subfractions) as Determined by NMR, Ion Mobility, and VAP in Treated Patients

Abstract

Introduction: LDL-P has been shown to be a better predictor of cardiovascular risk than LDL-C (Framingham Offspring, Jupiter, and MESA). HDL-P has been reported as a better predictor than HDL-C (Jupiter and MESA) and small dense LDL measurements have been reported as more predictive of cardiovascular disease progression than LDL-C (HATS). Clinicians rely on these markers to assess residual risk in treated patients. Hypothesis: NMR, ion mobility (IM), and VAP tests will report discordant results for LDL-P, HDL-P (or subfraction), and small dense LDL (or subfraction) in treated patients. Methods: This is a prospective study (#SCIML001 on ClinicalTrials.gov), approved by the Scripps Clinic (#IRB-14-6458). We aimed to determine the discordance between Liposcience NMR, Quest CardioIQ, and Atherotech VAP Plus. 102 patients older than 18 years on therapy for at least 30 days were included. A one-time fasting lab draw was obtained with all 3 lipid tests performed simultaneously on fresh samples. Concordance and discordance analysis was performed with the cut-off between normal and abnormal ranges. Results: Pearson correlations between LDL-P by VAP and NMR, NMR and IM, and VAP and IM were 0.886, 0.785, and 0.762, respectively. All 3 tests were concordant 63% and discordant 37% of the time. IM reported an abnormal LDL-P more commonly (28% of time vs NMR and 20% of the time vs VAP) when using the same cutoff value of 1000 as NMR. When using the cutoff of 1260 for LDL-P for IM, NMR was abnormal 15.6% of the time vs IM and VAP was abnormal 24% of the time vs IM. VAP more frequently reported an abnormal LDL-P vs NMR (27% of the time) and vs IM (32% of the time). VAP small LDL sub-fractions were more commonly reported as abnormal vs NMR and IM (27% and 32% respectively). Ion mobility more consistently reported a lower large HDL-P (48% of the time vs VAP and vs NMR). Conclusions: Correlations between advanced markers of residual risk were low and would give discordant signals on decisions to intensify therapy.