Beyond LDL-C levels, does remnant cholesterol estimation matter?

A significant presence in atherosclerotic cardiovascular disease: Remnant cholesterol: A review

The current first-line treatment for atherosclerotic cardiovascular disease (ASCVD) involves the reduction of a patient's low-density lipoprotein cholesterol (LDL-C) levels through the use of lipid-lowering drugs. However, even when other risk factors such as hypertension and diabetes are effectively managed, there remains a residual cardiovascular risk in these patients despite achieving target LDL-C levels with statins and new lipid-lowering medications. This risk was previously believed to be associated with lipid components other than LDL, such as triglycerides. However, recent studies have unveiled the crucial role of remnant cholesterol (RC) in atherosclerosis, not just triglycerides. The metabolized product of triglyceride-rich lipoproteins is referred to as triglyceride-rich remnant lipoprotein particles, and its cholesterol component is known as RC. Numerous pieces of evidence from epidemiological investigations and genetic studies demonstrate that RC plays a significant role in predicting the incidence of ASCVD. As a novel marker for atherosclerosis prediction, when LDL-C is appropriately controlled, RC should be prioritized for attention and intervention among individuals at high risk of ASCVD. Therefore, reducing RC levels through the use of various lipid-lowering drugs may yield long-term benefits. Nevertheless, routine testing of RC in clinical practice remains controversial, necessitating further research on the treatment of elevated RC levels to evaluate the advantages of reducing RC in patients at high risk of ASCVD.

Remnant cholesterol and intensive blood pressure control in older patients with hypertension: a post hoc analysis of the STEP randomized trial†

AIMS

Emerging evidence shows a close relationship between remnant cholesterol (RC) and hypertension. However, it is unknown whether RC is associated with the effects of intensive systolic blood pressure (SBP) lowering on cardiovascular outcomes.

METHODS AND RESULTS

We performed a post hoc analysis of the Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) trial. Participants were randomly allocated to intensive (110 to <130 mmHg) or standard (130 to <150 mmHg) treatment groups. The effects of intensive SBP lowering on the primary composite outcome (stroke, acute coronary syndrome, acute decompensated heart failure, coronary revascularization, atrial fibrillation, or cardiovascular death), the components thereof, and all-cause mortality were analysed by the tertile of baseline RC (lowest, middle, and highest). We followed 8206 patients for 3.33 years (median). The adjusted hazard ratios (HRs) [95% confidence interval (CI)] for the primary outcome were 1.06 (0.73-1.56), 0.58 (0.38-0.87), and 0.67 (0.46-0.96) in the lowest, middle, and highest RC tertiles, respectively (P for interaction = 0.11). However, significant heterogeneity in the treatment effects was observed when comparing the upper two tertiles with the lowest tertile (P for interaction = 0.033). For all-cause mortality, the adjusted HRs (95% CI) were 2.48 (1.30-4.73), 1.37 (0.71-2.65), and 0.42 (0.22-0.80) in the lowest, middle, and highest RC tertiles, respectively (P for interaction <0.0001).

CONCLUSION

Baseline RC concentrations were associated with the effects of intensive SBP lowering on the primary composite cardiovascular outcome and all-cause mortality in hypertensive patients. These results are hypothesis-generating and merit further study.

REGISTRATION

STEP ClinicalTrials.gov number: NCT03015311.

Distribution of triglyceride-rich lipoproteins and their remnants and their contribution to cardiovascular risk in the Mexican population

BACKGROUND AND AIMS

In recent years, scientific interest in triglyceride-rich lipoproteins (TRL) and remnant cholesterol has increased, focusing on the evidence that these lipoproteins are a causal factor for developing atherosclerotic cardiovascular disease (ASCVD). Furthermore, a high remnant concentration (>38 mg/dL) has been associated with several non-cardiovascular risks. We aimed in this study to describe the percentile distribution of remnant cholesterol. Additionally, we evaluated the association between remnant cholesterol plasma concentration and epidemiologically relevant cardio-metabolic outcomes such as hypertension, type 2 diabetes (T2D), and ASCVD.

METHODS

We analyzed data from 9,591 adults from the National Survey of Health and Nutrition (ENSANUT) 2018 with fasting blood samples and complete medical history questionnaires. We built multivariate models to evaluate the association between chronic diseases and blood remnant concentration. To compare our 2018-sub-sample against a population reference, we used the NHANES (2005-2014) publicly available datasets by ethnicity.

RESULTS

Remnants were independently associated with cardiovascular risk, diabetes, hypertension, obesity, and metabolic syndrome. For all outcomes, the blood remnant concentration was a stronger predictor than LDL. At all deciles, the blood remnant concentration was higher in ENSANUT-2018.

CONCLUSIONS

A remnant blood concentration above 38 mg/dL was highly prevalent among Mexicans. Remnants were significantly associated with a higher risk of diabetes, hypertension, obesity, and cardiovascular risk. This association occurred independently of other lipid markers.

Elevated remnant cholesterol is a risk factor for acute ischemic stroke

OBJECTIVES

Remnant cholesterol (RC) is thought to be an important pathogenic risk factor for atherosclerosis, however, the relationship between RC and acute ischemic stroke (AIS) is still unclear. This study aimed to determine whether fasting blood RC level is an independent risk factor for AIS.

MATERIALS AND METHODS

A retrospective analysis was performed on 650 patients with AIS and 598 healthy controls during the same time period. The association between RC and AIS was investigated using binary logistic regression, and the relationship between RC and AIS risk was demonstrated using Restricted Cubic Splines (RCS).

RESULTS

RC was significantly higher in the AIS group compared with control group, and was an independent risk factor for AIS when the covariates were not adjusted;After adjusting some covariates, RC was still an independent risk factor for AIS. The RCS analysis found the risk was non-linear: when RC concentration was less than 0.69 mol/L, the risk of AIS increased with the elevation of RC, and when RC concentration was more than or equal to 0.69 mol/L, the risk of AIS was insignificant with the elevation of RC. Correlation analysis revealed that RC was associated with diabetes and fasting glucose. Further analysis revealed that the incidence of AIS in diabetic patients increased significantly with the increase of RC, and RCS analysis revealed that the risk of AIS in diabetic patients increased with the increase of RC when RC was more than 1.15 mol/L.

CONCLUSIONS

This study confirms RC as an independent risk factor for AIS, which highlights a distinct non-linear association between RC levels and AIS risk. These findings suggest the need for targeted AIS risk assessment strategies, especially in diabetic patients, and underscore the relevance of RC as a biomarker in AIS risk stratification.

Remnant cholesterol trajectory and subclinical arteriosclerosis: a 10-year longitudinal study of Chinese adults

We aimed to identify different trajectories of remnant cholesterol (RC) and investigate the association of RC trajectories with vascular endothelial function and atherosclerosis progression in a longitudinal cohort of the Chinese population. A total of 521 participants were included in the flow-mediated vasodilation (FMD) subcohort study, and 7775 participants were included in the brachial-ankle pulse wave velocity (baPWV) subcohort study. All participants had ≥ 3 medical examinations during the 10-year follow-up period. In the FMD subcohort study, three distinct RC trajectories were identified according to the RC range and changing pattern over time: "low" (57.58%), "moderate" (30.90%) and "high" (11.52%). The proportion of the three groups with vascular endothelial dysfunction (FMD < 7.0%) was 20.00%, 39.75% and 60.00% respectively. Taking the low group as a reference, participants in the moderate and high groups had over 1.88 and 2.94 times the odds of vascular endothelial dysfunction (P = 0.048). In the baPWV subcohort study, three distinct RC trajectories were also identified: "low" (54.29%), "moderate" (38.97%) and "high" (6.74%). The proportion of the three groups with atherosclerosis (baPWV > 1400 cm/s) was 38.79%, 51.26% and 59.01% respectively. Taking the low group as a reference, participants in the moderate and high groups had over 1.46 and 2.16 times the odds of atherosclerosis (P < 0.001). The findings indicated that distinct RC trajectories are significantly associated with vascular endothelial function and atherosclerosis. Regular monitoring to identify persistent increases in RC may be more helpful in identifying individuals with a high risk of cardiovascular disease.

Bibliometric analysis of residual cardiovascular risk: trends and frontiers

BACKGROUND

The presence of residual cardiovascular risk is an important cause of cardiovascular events. Despite the significant advances in our understanding of residual cardiovascular risk, a comprehensive analysis through bibliometrics has not been performed to date. Our objective is to conduct bibliometric studies to analyze and visualize the current research hotspots and trends related to residual cardiovascular risk. This will aid in understanding the future directions of both basic and clinical research in this area.

METHODS

The literature was obtained from the Web of Science Core Collection database. The literature search date was September 28, 2022. Bibliometric indicators were analyzed using CiteSpace, VOSviewer, Bibliometrix (an R package), and Microsoft Excel.

RESULT

A total of 1167 papers were included, and the number of publications is increasing rapidly in recent years. The United States and Harvard Medical School are the leading country and institution, respectively, in the study of residual cardiovascular risk. Ridker PM and Boden WE are outstanding investigators in this field. According to our research results, the New England Journal of Medicine is the most influential journal in the field of residual cardiovascular risk, whereas Atherosclerosis boasts the highest number of publications on this topic. Analysis of keywords and landmark literature identified current research hotspots including complications of residual cardiovascular risk, risk factors, and pharmacological prevention strategies.

CONCLUSION

In recent times, global attention toward residual cardiovascular risk has significantly increased. Current research is focused on comprehensive lipid-lowering, residual inflammation risk, and dual-pathway inhibition strategies. Future efforts should emphasize strengthening international communication and cooperation to promote the comprehensive evaluation and management of residual cardiovascular risk.

Apolipoprotein B compared with low-density lipoprotein cholesterol in the atherosclerotic cardiovascular diseases risk assessment

The subendothelial retention of apolipoprotein B (apoB)-containing lipoproteins is a critical step in the initiation of pro-atherosclerotic processes. Recent genetic and clinical evidence strongly supports the concept that the lipid content of the particles is secondary to the number of circulating atherogenic particles that are trapped within the arterial lumen. Since each low-density lipoproteins (LDL) particle contains one apoB molecule, as do intermediate density lipoprotein (IDL) and very low-density lipoprotein (VLDL) particles, apoB level represents the total number of atherogenic lipoproteins, which is independent of particle density, and not affected by the heterogeneity of particle cholesterol content (clinically evaluated by LDL-cholesterol level). From this perspective, apoB is proposed as a better proxy to LDL-cholesterol for assessing atherosclerotic cardiovascular disease risk, especially in specific subgroups of patients, including subjects with diabetes mellitus, with multiple cardiometabolic risk factors (obesity, metabolic syndrome, insulin resistance, and hypertension) and with high triglyceride levels and very low LDL-cholesterol levels. Therefore, given the causal role of LDL-cholesterol in atherosclerotic cardiovascular disease (ASCVD) development, routine measurement of both LDL-cholesterol and apoB is of utmost importance to properly estimate global cardiovascular risk and to determine the 'residual' risk of ASCVD in patients receiving therapy, as well as to monitor therapeutic effectiveness.

Remnant cholesterol and atherosclerotic cardiovascular disease: Metabolism, mechanism, evidence, and treatment

This review aimed to summarize the evidence of elevated remnant cholesterol and the risks of atherosclerotic cardiovascular disease (ASCVD) and to search for further guidance in clinical therapy. The lipids-lowering treatments such as statins and ezetimibe targeted on low-density lipoprotein cholesterol (LDL-C) have always been the first-line therapy for ASCVD. However, even after statins or new lipid-lowering drugs lowered LDL-C to recommended concentrations, and with other risk factors well-controlled, such as high blood pressure, the risks of developing ASCVD remained. Remnant cholesterol (RC) referred to the cholesterol contained in all remnant lipoprotein particles, which was the cholesterol in the hydrolyzed very-low-density lipoprotein and intermediate-density lipoprotein in the fasting state, and the cholesterol in the chylomicron remnants in the postprandial state. Evidence from in vitro and animal pathogenic mechanisms studies, epidemiology, and genetic studies all indicated that RC played an important role in predicting the incidence of ASCVD. As a new indicator to reflect atherosclerosis, especially when LDL-C has been controlled to a recommended level, RC was considered as a priority treatment target for people at high risk of ASCVD. The use of statins, fibrates, APOC3 inhibitors, PCSK9 inhibitors, and omega-3 fatty acids to reduce RC levels in the plasma may provide long-term benefits. However, the standardized detection of RC was still controversial, and more studies on appropriate treatments of elevated RC are urgently needed. These positive trials may benefit more patients at high ASCVD risks worldwide in the future.

How should low-density lipoprotein cholesterol be calculated in 2022?

PURPOSE OF REVIEW

The reference method for low-density lipoprotein-cholesterol (LDL-C) quantitation is β-quantification, a technically demanding method that is not convenient for routine use. Indirect calculation methods to estimate LDL-C, including the Friedewald equation, have been used since 1972. This calculation has several recognized limitations, especially inaccurate results for triglycerides (TG) >4.5 mmol/l (>400 mg/dl). In view of this, several other equations were developed across the world in different datasets.The purpose of this review was to analyze the best method to calculate LDL-C in clinical practice by reviewing studies that compared equations with measured LDL-C.

RECENT FINDINGS

We identified 45 studies that compared these formulae. The Martin/Hopkins equation uses an adjustable factor for TG:very low-density lipoprotein-cholesterol ratios, validated in a large dataset and demonstrated to provide more accurate LDL-C calculation, especially when LDL <1.81 mmol/l (<70 mg/dl) and with elevated TG. However, it is not in widespread international use because of the need for further validation and the use of the adjustable factor. The Sampson equation was developed for patients with TG up to 9 mmol/l (800 mg/dl) and was based on β-quantification and performs well on high TG, postprandial and low LDL-C samples similar to direct LDL-C.

SUMMARY

The choice of equation should take into the level of triglycerides. Further validation of different equations is required in different populations.

Remnant cholesterol predicts cardiovascular disease beyond LDL and ApoB: a primary prevention study

AIMS

Emerging evidence suggests that remnant cholesterol (RC) promotes atherosclerotic cardiovascular disease (ASCVD). We aimed to estimate RC-related risk beyond low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apoB) in patients without known ASCVD.

METHODS AND RESULTS

We pooled data from 17 532 ASCVD-free individuals from the Atherosclerosis Risk in Communities study (n = 9748), the Multi-Ethnic Study of Atherosclerosis (n = 3049), and the Coronary Artery Risk Development in Young Adults (n = 4735). RC was calculated as non-high-density lipoprotein cholesterol (non-HDL-C) minus calculated LDL-C. Adjusted Cox models were used to estimate the risk for incident ASCVD associated with log RC levels. We also performed discordance analyses examining relative ASCVD risk in RC vs. LDL-C discordant/concordant groups using difference in percentile units (>10 units) and clinically relevant LDL-C targets. The mean age of participants was 52.3 ± 17.9 years, 56.7% were women and 34% black. There were 2143 ASCVD events over the median follow-up of 18.7 years. After multivariable adjustment including LDL-C and apoB, log RC was associated with higher ASCVD risk [hazard ratio (HR) 1.65, 95% confidence interval (CI) 1.45-1.89]. Moreover, the discordant high RC/low LDL-C group, but not the low RC/high LDL-C group, was associated with increased ASCVD risk compared to the concordant group (HR 1.21, 95% CI 1.08-1.34). Similar results were shown when examining discordance across clinical cutpoints.

CONCLUSIONS

In ASCVD-free individuals, elevated RC levels were associated with ASCVD independent of traditional risk factors, LDL-C, and apoB levels. The mechanisms of RC association with ASCVD, surprisingly beyond apoB, and the potential value of targeted RC-lowering in primary prevention need to be further investigated.

Comparative assessment of LDL-C and VLDL-C estimation in familial combined hyperlipidemia using Sampson's, Martin's and Friedewald's equations

Background

Sampson et al. developed a novel method to estimate very low-density lipoprotein cholesterol (VLDL-C) and low-density lipoprotein cholesterol (LDL-C) in the setting of hypertriglyceridemia. Familial Combined Hyperlipidemia (FCHL) is a common primary dyslipidemia in which lipoprotein composition interferes with LDL-C estimation. This study aimed to evaluate performance of LDL-C using this new method (LDL-S) compared with LDL-C estimated by Friedewald’s and Martin eq. (LDL-F, LDL-M) in FCHL.

Methods

Data were collected from 340 subjects with confirmed FCHL. Concordance for VLDL-C measured by ultracentrifugation and LDL-C estimated using these measures compared to Sampson’s, Martin’s and Friedewald’s equations was performed using correlation coefficients, root mean squared error (RMSE) and bias. Also, concordance of misclassified metrics according to LDL-C (< 70 and < 100 mg/dL) and Apo B (< 80 and < 65 mg/dL) thresholds were assessed.

Results

Sampson’s equation was more accurate (RMSE 11.21 mg/dL; R² = 0.88) compared to Martin’s (RMSE 13.15 mg/dL; R² = 0.875) and the Friedewald’s equation (RMSE 13.7 mg/dL; R² = 0.869). When assessing performance according to LDL-C, Sampson’s had highest correlation and lowest RMSE compared to other equations (RMSE 19.99 mg/dL; R² = 0.840). Comparing performance strength across triglyceride levels, Sampson’s showed consistently improved correlations compared to Martin’s and Friedewald’s formulas for increasing triglycerides and for the FCHL phenotype of mixed dyslipidemia. Sampson’s also had improved concordance with treatment goals.

Conclusions

In FCHL, VLDL-C and LDL-C estimation using Sampson’s formula showed higher concordance with lipid targets assessed using VLDL-C obtained by ultracentrifugation compared with Friedewald’s and Martin’s equations. Implementation of Sampson’s formula could improve treatment monitoring in FCHL.