Discordantly Elevated Apolipoprotein B versus Low-Density Lipoprotein Cholesterol is Associated with Remnant Lipoproteins and Increased Cardiovascular Events

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S11-S11
Author(s):  
Paola Ramos ◽  
Leslie Donato ◽  
Linnea Baudhuin ◽  
Vlad Vasile ◽  
Allan Jaffe ◽  
...  

Abstract Atherosclerotic cardiovascular disease is a result of low-density lipoprotein (LDL) particles becoming trapped in arterial walls and forming plaques which ultimately restrict blood-flow. LDL cholesterol (LDL-C) and apolipoprotein B (apoB) are highly correlated measures of plaque-causing LDL particles. Both have been shown to predict major adverse cardiac events (MACE). ApoB is also carried on remnant lipoproteins (RLP). RLP-cholesterol (RLP-C) is increasingly appreciated as a MACE risk-factor. This study aimed to define discordances between apoB and LDL-C in a large data set from a clinical reference laboratory. We then applied this definition to evaluate which measure predicted the risk of MACE in a patient cohort referred for coronary angiography with >10 years follow-up. LDL-C was measured by beta-quantification and RLP-C was defined as total cholesterol – LDL-C – HDL-C. Apo B discordance relative to LDL-C was determined by linear regression in a discovery cohort (n=17,203) using beta quantification. Discordance was defined by quartiles of the residual-apoB (expected–actual); discordant-low (<25th percentile), concordant (25th to 75th percentile) and discordant-high (>75th percentile). Associations with prevalence and incident of MACE were evaluated by odds-ratio and logistic regression. Risk of MACE was calculated based on the apoB-discordance and reported MACE events by several years follow up in a separate cohort (n=501). In the discovery cohort, age ranged from 18-95 years, 51% were female and mean (±SD) lipid values were: ApoB: 100.4 ± 30.0mg/dl, LDL-C: 121.7 ± 47.9mg/dl, and RLP-C: 17.2 ± 26.9mg/dl. Expected-apoB was described by the formula: (LDL-c X 0.6278 + 24.07, R=0.88). Residual-apoB (discordance) ranged from -1037 to 581.2 with a mean 0.01±18.6, and notably increased with triglyceride concentration (rho=0.65) and with RLP-C (rho=0.64), but was minimally influenced by apoB (rho=0.35) and LDL-C (rho=0.009) (p<0.001 all cases). In the clinical follow-up cohort, age ranged from 26-77 years, 42% were female, 64% were current/former smokers, and 28% were on lipid-lowering therapy. Mean (±SD) lipids were: apoB: 97.8 ± 20.9mg/dl, LDL-C: 124.6 ± 36.6mg/dl, and RLP-C: 34.9 ± 25.6mg/dl. Serum triglycerides among subjects discordant-low apoB, concordant and discordant-high apoB were 148mg/dL, 157mg/dL and 238mg/dL, respectively; similarly for RLP-C. A total of 192 events occurred during a mean of 9 years follow-up. Subjects with discordantly elevated apoB had a significantly higher incidence of MACE compared to those with concordant values (47% vs. 36%, p=0.03). There was no difference in MACE for subjects with discordantly low apoB (35% vs. 36%). These data support previous reports of an association between apoB and LDL-C and the superior performance of apoB when discordantly elevated. Our data expand on previous studies by applying an externally defined threshold for discordant-apoB. Our data indicate that triglycerides, RLP-C are associated with discordances and MACE.

Author(s):  
Salim S Virani ◽  
Lechauncy D Woodard ◽  
Supicha Sookanan ◽  
Cassie R Landrum ◽  
Tracy H Urech ◽  
...  

Background: Although current cholesterol performance measures define good quality as low density lipoprotein cholesterol (LDL-C) levels < 100mg/dl in cardiovascular disease (CVD) patients, they provide a snap shot at one time point and do not inform whether an appropriate action was taken to manage elevated LDL-C levels. We assessed frequency and predictors of this appropriate response (AR). Methods: We used administrative data to assess 22,902 CVD patients receiving care in a Veterans Affairs network of 7 hospitals and affiliated clinics. We determined the proportion of CVD patients at LDL-C goal <100 mg/dl, and the proportion of patients with uncontrolled LDL-C levels (>100 mg/dl) who had an AR [defined as the initiation or dosage increase of a lipid lowering medication (LLM), addition of a new LLM, receipt of maximum dosage or >1 LLM, or LDL-C reading <100 mg/dl] at 45 days follow-up. Logistic regression was performed to evaluate facility, provider and patient characteristics associated with AR. Results: LDL-C levels were at goal in 16,350 (71.4%) patients. An additional 2,110 (9.2%) had an AR at 45 days of follow-up. Controlling for clustering between facilities and patient's illness severity, history of diabetes (OR 1.18, 95% CI 1.03-1.35), hypertension (OR 1.21, 95% CI 1.02-1.44), patients showing good medication adherence (medication possession ratio > 0.8) [OR 2.29, 95% CI 1.99-2.64] were associated with AR. Older CVD patients (age >75 years) were less likely to receive AR (OR 0.60, 95% CI 0.52-0.70). Teaching vs. non-teaching facility (p=0.40), physician vs. non-physician provider (p=0.14), specialist vs. non-specialist primary care provider (p=0.12), and patient's race (p=0.12) were not predictors of AR. Conclusion: Among patients with CVD and LDL-C above guideline recommended levels, only one-third receive AR. Diabetic and hypertensive CVD patients are more likely to receive AR, whereas older Veterans with CVD receive AR less often likely reflecting providers' belief of lack of efficacy from treatment intensification in older CVD patients. Our findings are important for quality improvement and policy making initiatives as they provide more actionable information compared with isolated LDL-C goal attainment as a quality indicator.


2015 ◽  
Vol 128 (12) ◽  
pp. 877-882 ◽  
Author(s):  
Montse Guardiola ◽  
Núria Plana ◽  
Daiana Ibarretxe ◽  
Anna Cabré ◽  
Marta González ◽  
...  

The proprotein convertase subtilisin/kexin type 9 (PCSK9) gene regulates cholesterol homoeostasis by accelerating low-density lipoprotein receptor (LDLR) degradation resulting in the decreased catabolism of low-density lipoprotein (LDL) leading to hypercholesterolaemia. PCSK9 has also been related to other metabolic risk factors such as triglycerides (TGs) and glucose levels and body mass index (BMI). Therefore, our aim was to study the relationship between the PCSK9 and the lipid and lipoprotein profile. We studied 267 diabetic and metabolic syndrome patients who were not receiving any lipid-lowering therapy. We measured circulating lipids, cholesterol in remnant lipoproteins (RLPc) and PCSK9 levels. A detailed lipoprotein profile was determined based on NMR. Plasma PCSK9 levels were significantly and positively correlated with TG (r=0.136, P=0.033), total cholesterol (r=0.219, P<0.001) and apoB (apolipoprotein B; r=0.226, P=0.006) circulating levels and with an atherogenic profile of lipoprotein subclasses. In further detail, circulating PCSK9 levels were positively correlated with large very-low density lipoprotein (VLDL) particles, (r=0.210, P=0.001) and with their remnants, the intermediate-density lipoprotein (IDL) particles (r=0.206, P=0.001); positively correlated with smaller LDL particles (for small LDL: r=0.224, P<0.001; for medium small LDL: r=0.235, P<0.001; and for very small LDL: r=0.220, P<0.001); and with high-density lipoprotein (HDL) particles (r=0.146, P<0.001), which is mainly explained by the PCSK9 correlation with the smallest HDL particles (r=0.130, P=0.037). In addition, circulating PCSK9 levels were positively correlated with the pro-atherogenic circulating RLPc levels (r=0.171, P=0.006). All of the correlations were adjusted by age, gender and BMI. PCSK9 levels are significantly and positively correlated with atherogenic lipoproteins such as large VLDL, IDL, the smallest LDL, the smallest HDL particles and RLPc levels.


1997 ◽  
Vol 322 (3) ◽  
pp. 765-769 ◽  
Author(s):  
Fabio TANFANI ◽  
Tiziana GALEAZZI ◽  
Giovanna CURATOLA ◽  
Enrico BERTOLI ◽  
Gianna FERRETTI

The secondary structure of apolipoprotein B-100 in low-density lipoprotein (LDL) subfractions was analysed by Fourier-transform IR spectroscopy. LDLs were isolated in three density ranges by gradient centrifugation of human plasma from healthy volunteers. The spectra revealed differences in the lipid content and composition of the three LDL fractions. The secondary structure of apolipoprotein B-100 was the same in the two fractions corresponding to the large less-dense LDL particles, whereas a lower content of β-strands was found in the third fraction corresponding to the smaller denser LDL particles. Analysis of the spectroscopic data suggests that, in the same set of LDL subfractions, the particle size is probably the cause of the observed differences in apolipoprotein B-100 secondary structure.


2009 ◽  
Vol 118 (5) ◽  
pp. 333-339 ◽  
Author(s):  
Allan D. Sniderman ◽  
Jacqueline De Graaf ◽  
Patrick Couture ◽  
Ken Williams ◽  
Robert S. Kiss ◽  
...  

The objectives of this analysis are to re-examine the foundational studies of the in vivo metabolism of plasma LDL (low-density lipoprotein) particles in humans and, based on them, to reconstruct our understanding of the governance of the concentration of plasma LDL and the maintenance of cholesterol homoeostasis in the hepatocyte. We believe that regulation of cholesterol homoeostasis within the hepatocyte is demonstrably more complex than envisioned by the LDL receptor paradigm, the conventional model to explain the regulation of plasma LDL and the fluxes of cholesterol into the liver, a model which was generated in the fibroblast but has never been fully validated in the hepatocyte. We suggest that the LDL receptor paradigm should be reconfigured as the apoB (apolipoprotein B) paradigm, which states that the rate at which LDL particles are produced is at least an important determinant of their concentration in plasma as the rate at which they are cleared from plasma and that secretion of cholesterol within VLDL (very-low-density lipoprotein) particles is an important mechanism of maintaining cholesterol homoeostasis within the hepatocyte. These two paradigms are not mutually exclusive. The LDL receptor paradigm, however, includes only one critical aspect of the regulation of plasma LDL, namely the rate at which LDL particles are cleared through the LDL receptor pathway, but ignores another – the rate at which LDL particles are added to the plasma compartment. The apoB paradigm includes both and points to a different model of how the hepatocyte achieves cholesterol homoeostasis in a complex metabolic environment.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Connie N Hess ◽  
Christopher P Cannon ◽  
Joshua A Beckman ◽  
Philip Goodney ◽  
Manesh R Patel ◽  
...  

Introduction: Low-density lipoprotein cholesterol (LDL-C) is associated with heightened risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE) in patients with peripheral artery disease (PAD). Strategies that lower LDL-C levels reduce this risk. Hypothesis: We hypothesized that real-world PAD patients are overall undertreated with lipid lowering therapies (LLT) but that LLT use and achieved LDL-C are improved in high risk patients with ischemic events. Methods: Patients with PAD in the MarketScan database linked to PROGNOS lab data from January 1, 2014 through December 31, 2018 were examined. Outcomes included use of LLT, defined as high intensity (HI) (high intensity statin, any statin plus ezetimibe, or any use of a PCSK9 inhibitor), low intensity (LI) (any other lipid regimen), or no therapy, and follow up LDL-C level. Goal LDL-C was defined as <70 mg/dl. Results: Among 18,747 PAD patients, 25% were on HI LLT, 43% were on LI LLT, and 32% were on no therapy at baseline (Figure A). The median LDL-C was 91 mg/dl (IQR 70, 118), and 25% of patients were at goal (Figure B). After a median follow up of 18 months, use of HI LLT increased by 4%, the median LDL-C decreased by 5 mg/dl, and an additional 3% of patients were at goal LDL-C. Greater use of HI LLT was observed among patients with a MACE (55%) or MALE (41%) event during follow up compared with patients without an ischemic event (26%) during follow up (Figure C). Follow up LDL-C levels remained above goal for most patients (post-MACE: median LDL-C 77 mg/dl, 42% patients at goal; post-MALE: median LDL-C 80 mg/dl, 36% patients at goal). Conclusions: In PAD patients, use of LLT is suboptimal, and LDL-C levels remain elevated. After an ischemic event, LLT use is intensified, with greater use of HI LLT observed after MACE than MALE. Despite this, LLT remains underutilized, with >50% of patients not at goal LDL-C. Strategies to better implement proven therapies to reduce risk in this high risk population are needed.


2006 ◽  
Vol 00 (02) ◽  
Author(s):  
Michael H Davidson

While the primary lipid target for chronic heart disease (CHD) risk management remains low-density lipoprotein (LDL) or ‘bad’ cholesterol, the treatment of elevated triglyceride (TG) is now also recommended. Elevated TG is believed to increase cardiovascular risk because certain TG-rich lipoproteins, called remnant lipoproteins—partially degraded chylomicrons and very low density lipoproteins (VLDL)—are atherogenic. Hypertriglyceridemia, together with low levels of highdensity lipoprotein (HDL) or ‘good’ cholesterol and an increased prevalence of small, dense LDL particles, comprise a triad of lipid risk factors known as atherogenic dyslipidemia.


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