Background/Purpose: Systemic lupus erythematosus (SLE) associates with atherosclerotic cardiovascular (CV) disease and related mortality. This is contributed to, but cannot be fully explained, by traditional CV risk factors, treatments and SLE-specific factors. Coronary artery calcium scores (CAC), by computed tomography (CT) measure atherosclerotic burden and can predict CV events. Non-calcified plaque (NCP), common in SLE, can also be quantified and may be more metabolically active and unstable. Routine lipids are unhelpful in distinguishing SLE patients with or without either CAC or NCP. Nuclear magnetic resonance (NMR) spectroscopy allows determination of the size and concentration of lipoprotein classes and subclasses, and has been used to evaluate CV risk in many populations. The aim of this work is to determine whether differences in NMR lipoprotein particle numbers or size can distinguish between SLE patients with and without CAC. An additional aim was to establish whether NMR parameters associate with quantified NCP or calcified plaque.

Methods: As part of a longitudinal lupus cohort, SLE patients, without known atherosclerotic disease, had coronary CT angiography performed. CAC scores were calculated according to the Agatston system. Lipoprotein particle numbers and size were evaluated by NMR. The initial statistical analysis compared those with and without calcified and NCP using t-tests. Further evaluation involved the calculation of correlation coefficients to evaluate the relationship between lipoprotein abnormalities and the burden of calcified and NCP.

Results: Sixty-nine SLE patients were evaluated, 64 (93%) female, 49 (71%) were African-American and 20 (29%) were Caucasian. Significant NCP was present in 41 (59%) and CAC was present in 14 (20%). Individuals with NCP had significantly larger very low-density lipoprotein (VLDL) particles (44.8 ±5.5 nm versus 47.7 ±6.1 nm, p= 0.042). None of the other lipoprotein parameters were significantly different between those who had calcified or NCP. Considering the volume and extent of CAC and NCP; (Table 1) higher triglycerides were observed with increasing levels of CAC. Increasing volumes of NCP were associated with higher LDL particle number and larger VLDL size. The lipoprotein insulin resistance scores were also positively associated with NCP.

Conclusion: The mechanisms underlying atherosclerosis in SLE are poorly understood. NCP is highly prevalent in SLE and may be contributed to by differences in LDL, VLDL and insulin resistance measures, not evaluated in routine lipid profiles. Further longitudinal analysis will determine whether these abnormalities associate with progression of disease and can be considered prognostic markers.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/non-calcified-coronary-artery-plaque-associates-with-adverse-lipoprotein-profiles-in-systemic-lupus-erythematosus/