Directly Measured vs. Calculated Low-Density Lipoprotein Cholesterol Does Not Identify Additional Individuals With Coronary Artery Disease and Diabetes at Higher Risk of Adverse Events: Insight From a Large Percutaneous Coronary Intervention Cohort in Asia

Differential lipid impact on mortality in patients undergoing CABG versus PCI

BACKGROUND AND AIMS

The impact of revascularization type, including coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI), on lipid control efficacy remains unclear. We aim to assess the associations of lipid levels with all-cause and cardiovascular mortality in patients undergoing PCI or CABG.

METHODS

We used data from the ChinaHEART cohort and enrolled patients with a self-reported history of PCI or CABG. We employed Cox proportional hazards regression models to evaluate the associations between lipid levels and mortality.

RESULTS

Our analysis included 29 003 participants, of whom 23 959 (82.6 %) undergoing PCI and 5044 (17.4 %) undergoing CABG. Over a median follow-up of 3.22 years, 1007 deaths were recorded, with 579 attributed to cardiovascular causes. Each 1 mmol/L increase in TC, LDL-C, and non-HDL-C was associated with multivariable-adjusted HRs of 1.16 (95 % CI 1.10,1.22), 1.23 (1.15,1.32) and 1.16 (1.10,1.23) for all-cause mortality, respectively. Similar results were observed in patients undergoing PCI, while no significant associations were found in patients undergoing CABG.

CONCLUSIONS

Elevated lipid levels are associated with all-cause and cardiovascular mortality in revascularization patients. Suboptimal lipid control appears to have a more pronounced effect on mortality in patients undergoing PCI. The effects of elevated lipid levels on mortality in CABG patients may need a longer follow-up to manifest due to the more complex nature of the grafts and the long-term adaptation process.

The clinical impact of estimating low-density lipoprotein cholesterol (LDL-C) using different equations in the general population

BACKGROUND

Low-density lipoprotein cholesterol (LDL-C) is associated with atherosclerotic cardiovascular disease (ASCVD). Friedewald, Sampson, and Martin-Hopkins equations are used to calculate LDL-C. This study compares the impact of switching between these equations in a large geographically defined population.

MATERIALS AND METHODS

Data for individuals who had a lipid panel ordered clinically between 2010 and 2019 were included. Comparisons were made across groups using the two-sample t-test or chi-square test as appropriate. Discordances between LDL measures based on clinically actionable thresholds were summarized using contingency tables.

RESULTS

The cohort included 198,166 patients (mean age 54 years, 54% female). The equations perform similarly at the lower range of triglycerides but began to diverge at a triglyceride level of 125 mg/dL. However, at triglycerides of 175 mg/dL and higher, the Martin-Hopkins equation estimated higher LDL-C values than the Samson equation. This discordance was further exasperated at triglyceride values of 400 to 800 mg/dL. When comparing the Sampson and Friedewald equations, at triglycerides are below 175 mg/dL, 9% of patients were discordant at the 70 mg/dL cutpoint, whereas 42.4% were discordant when triglycerides are between 175 and 400 mg/dL. Discordance was observed at the clinically actionable LDL-C cutpoint of 190 mg/dL with the Friedewald equation estimating lower LDL-C than the other equations. In a high-risk subgroup (ASCVD risk score > 20%), 16.3% of patients were discordant at the clinical cutpoint of LDL-C < 70 mg/dL between the Sampson and Friedewald equations.

CONCLUSIONS

Discordance at clinically significant LDL-C cutpoints in both the general population and high-risk subgroups were observed across the three equations. These results show that using different methods of LDL-C calculation or switching between different methods could have clinical implications for many patients.

Comparison between the Friedewald, Martin and Sampson Equations and LDL-C Quantification by Ultracentrifugation in a Mexican Population

Low-density lipoprotein cholesterol (LDL-C), which makes up about 70% of the cholesterol in the blood, is critical in the formation of arteriosclerotic plaques, increasing the risk of heart disease. LDL-C levels are estimated using Friedewald, Martin and Sampson equations, though they have limitations with high triglycerides. Our aim is to compare the effectiveness of these equations versus the ultracentrifugation technique in individuals with and without dyslipidemia and identify precision. There were 113 participants, 59 healthy controls and 54 dyslipidemic patients. Samples were collected after fasting. LDL-C was estimated using the Friedewald, Martin and Sampson equations. The purified LDL-C, ultracentrifugated and dialysized control group without dyslipidemia vs. patients with coronary artery disease (CAD) showed differences in age, HDL-C, triglycerides and glucose non-HDL-C (p = 0.001 in all). There were correlations in CGWD between ultracentrifugation and Sampson R-squared (R2) = 0.791. In the dyslipidemia control group, ultracentrifugation and Friedewald R2 = 0.911. In patients with CAD, correlation between ultracentrifugation and Sampson R2 = 0.892; Bland-Altman confirmed agreement in controls without dyslipidemia. The Martin and Sampson equations are interchangeable with ultracentrifugation. Conclusion: The role of LDL analysis using precise techniques is necessary to obtain better control of disease outcomes after the use of precise therapies and suggests verifying its importance through clinical trials.

Associations of remnant cholesterol with cardiovascular and cancer mortality in a nationwide cohort

The health significance of triglyceride-rich lipoproteins, also known as remnant cholesterol, has been increasingly recognized. However, evidence of their associations with cause-specific mortality in the general population was previously insufficient. To explore these associations and their heterogeneities across subgroups, a prospective cohort study was conducted including 3,403,414 community-based participants from ChinaHEART, an ongoing government-funded public health program throughout China, from November 2014 through December 2022. The study assessed mortality risk of all-cause mortality, cardiovascular disease (CVD) mortality (including mortality from ischemic heart diseases (IHD), ischemic stroke (IS), and hemorrhagic stroke (HS), separately), and cancer mortality (including lung cancer, stomach cancer, and liver cancer, separately). During the 4-year follow-up, 23,646 individuals died from CVD (including 8807 from IHD, 3067 from IS, and 5190 from HS), and 20,318 from cancer (including 6208 from lung cancer, 3013 from liver cancer, and 2174 from stomach cancer). Compared with individuals with remnant cholesterol <17.9 mg/dL, multivariable-adjusted mortality hazard ratios (HRs) for individuals with remnant cholesterol ≥27.7 mg/dL were 1.03 (1.00-1.05) for all-cause mortality, 1.17 (1.12-1.21) for CVD (1.19 (1.12-1.27) for IHD mortality, and 1.22 (1.09-1.36) for IS mortality), and 0.90 (0.87-0.94) for all-cancer mortality (0.94 (0.87-1.02) for lung cancer, 0.59 (0.53-0.66) for liver cancer, and 0.73 (0.64-0.83) for stomach cancer). In summary, this study revealed a correlation between increased remnant cholesterol levels and an elevated risk of cardiovascular disease mortality, as well as a reduced risk of mortality for certain types of cancer.