Burden of elevated lipoprotein(a) among patients with atherosclerotic cardiovascular disease: Evidence from a systematic literature review and feasibility assessment of meta-analysis

BACKGROUND

Elevated lipoprotein(a) [Lp(a)] level is an independent genetic risk factor that increases the risk of atherosclerotic cardiovascular disease (ASCVD) by 2-4 fold. We aimed to report the burden of clinically relevant elevated Lp(a) in secondary prevention ASCVD population as the evaluation of such evidence is lacking.

METHODS

A systematic literature review (SLR) was conducted using Embase®, MEDLINE®, and MEDLINE® In-Process databases to identify studies reporting burden of elevated Lp(a) levels from January 1, 2010, to March 28, 2022. Full-text, English-language studies including ≥500 participants with ≥1 Lp(a) assessment were included.

RESULTS

Sixty-one studies reported clinical burden of elevated Lp(a). Of these, 25 observational studies and one clinical trial reported clinical burden of clinically relevant elevated Lp(a) levels. Major clinical outcomes included major adverse cardiovascular event (MACE; n = 20), myocardial infarction (MI; n = 11), revascularization (n = 10), stroke (n = 10), cardiovascular (CV) mortality (n = 9), and all-cause mortality (n = 10). Elevated Lp(a) levels significantly increased the risk of MACE (n = 15) and revascularization (n = 8), while they demonstrated a trend for positive association with remaining CV outcomes. Meta-analysis was not feasible for included studies due to heterogeneity in Lp(a) thresholds, outcome definitions, and patient characteristics. Three studies reported humanistic burden. Patients with elevated Lp(a) levels had higher odds of manifesting cognitive impairment (odds ratio [OR] [95% confidence interval; CI]: 1.62 [1.11-2.37]) and disability related to stroke (OR [95% CI]:1.46 [1.23-1.72)]) (n = 2). Elevated Lp(a) levels negatively correlated with health-related quality of life (R = -0.166, p = 0.014) (n = 1). A single study reported no association between elevated Lp(a) levels and economic burden.

CONCLUSIONS

This SLR demonstrated a significant association of elevated Lp(a) levels with major CV outcomes and increased humanistic burden in secondary prevention ASCVD population. These results reinforce the need to quantify and manage Lp(a) for CV risk reduction and to perform further studies to characterize the economic burden.

Combined effect of D-dimer, hs-CRP, and Lp(a) on 5-year clinical outcomes after percutaneous coronary intervention: A large real-world study in China

To reduce cardiovascular risk in patients with established coronary heart disease, the present study investigated the combined effect of D-dimer, high-sensitivity C-reactive protein (hs-CRP), and lipoprotein(a) [Lp(a)] on long-term cardiovascular outcomes from the perspectives of thrombosis, inflammation, and lipid risk simultaneously. Consecutive 10,724 patients with percutaneous coronary intervention (PCI) were enrolled throughout 2013. Over a median follow-up of 5.1 years, each individual elevation of D-dimer, hs-CRP, and Lp(a) was associated with poor ischemic outcomes but not bleeding. Concurrent high D-dimer, hs-CRP, and Lp(a) had even greater risks of all-cause death (hazard ratio [HR] 2.714, 95% confidence interval [CI] 1.742-4.231) and cardiac death (HR 4.152, 95% CI 2.207-7.812) and had incremental value beyond the traditional risk factors model. Concurrent high D-dimer, hs-CRP, and Lp(a) levels had a synergistic effect on adverse 5-year ischemic outcomes, highlighting that the potential utility of simultaneous assessment of multiple cardiovascular risk biomarkers may help to identify high-risk patients after PCI.

Association of C-peptide and lipoprotein(a) as two predictors with cardiometabolic biomarkers in patients with type 2 diabetes in KERCADR population-based study

We sought association between serum Lipoprotein(a) and C-Peptide levels as two predictors with cardiometabolic biomarkers in patients with type 2 diabetes mellitus. This nested case-control study was conducted on 253 participants with type 2 diabetes mellitus and control from the second phase of the KERCADR cohort study. The participants were randomly allocated into case and control groups. The quantitative levels of Lipoprotein(a) and C-Peptide were measured by ELISA. Atherogenic indices of plasma were measured. The plasma Atherogenic Index of Plasma significantly decreased (P = 0.002) in case-male participants, and plasma Castelli Risk Index II level significantly increased (P = 0.008) in control-male participants with the highest dichotomy of Lipoprotein(a). The plasma Atherogenic Index of Plasma level in case-female participants significantly increased (P = 0.023) with the highest dichotomy of C-Peptide. Serum C-Peptide level significantly increased (P = 0.010 and P = 0.002, respectively) in control-male participants with the highest dichotomies of Atherogenic Index of Plasma and Castelli Risk Index I. There was a significant association between the highest quartile of C-Peptide and higher anthropometric values in case participants; and higher atherogenic indices of plasma and anthropometric values in control participants. Raised serum C-peptide than raised Lipoprotein(a) can be a prior predictor for cardiometabolic disease risk in healthy participants and patients with type 2 diabetes mellitus with increased cardiometabolic biomarkers. Case and control males with general and visceral obesity and case and control females with visceral obesity are exposure to increased C-peptide, respectively. Lipoprotein(a) may be risk independent biomarker for type 2 diabetes mellitus. Reducing raised Lipoprotein(a) levels to less than 30ng/ml with strict control of low density lipoprotein cholesterol would be the best approach to prevent coronary artery disease consequences. It is suggested that a screening system be set up to measure the Lp(a) levels in the community for seemingly healthy people or individuals with one or more cardiometabolic biomarkers.

Coronary calcification is associated with elevated serum lipoprotein (a) levels in asymptomatic men over the age of 45 years: A cross-sectional study of the Korean national health checkup data

Lipoprotein a (Lp (a)) and coronary artery calcification (CAC) are markers of coronary artery and cardiovascular diseases. However, the association between Lp (a) and CAC in asymptomatic individuals remains unclear. In this study, we aimed to determine the influence of Lp (a) on CAC in asymptomatic individuals.We included 2019 asymptomatic Korean adults who underwent testing for a coronary artery calcium score (CACS) and Lp (a) at the Gangnam Severance Hospital Health Checkup Center in Korea from January 2017 to August 2019. Participants were divided into 2 groups: CACS = 0 and CACS > 0. Factors affecting the CACS were analyzed by sex. Because age is a major risk factor for atherosclerosis, ≥45 years in men and ≥55 years in women, we further divided participants into 4 subgroups (≥45 and <45 in men, ≥55 and <55 in women). Factors affecting the CACS in the 4 groups were analyzed.There was a positive correlation between the CACS and traditional cardiovascular risk factors. Lp (a) positively correlated with the CACS in men (P < .01) and remained significant after multivariable logistic regression (P < .01). The same result was observed in men aged ≥45 years (P < .01).Lp (a) is an independently associated factor of CAC and a marker of coronary atherosclerosis in asymptomatic men aged ≥45 years. In asymptomatic men aged ≥45 years, Lp (a) should be measured, and intensive Lp (a)-lowering treatment should be considered.

Prognostic Value of Lipoprotein(a) Levels in Patients Undergoing Coronary Angiography for Premature Acute Coronary Syndromes

Little is known about the association between lipoprotein(a) [Lp(a)] levels and future ischemic cardiovascular events in patients with premature acute coronary syndrome (ACS). A total of 1464 consecutive patients who underwent coronary angiography for premature ACS (males <45 years and females <55 years) were enrolled in this study. Patients were divided into quartiles according to serum Lp(a) levels (Q1: ≤11.1 nmol/L; Q2: 11.1-27.7 nmol/L; Q3: 27.7-79.3 nmol/L; and Q4: >79.3 nmol/L). Major adverse cardiovascular events (MACEs) increased with Lp(a) quartiles after 2-year follow-up (among quartiles, respectively; P = .001). Kaplan-Meier curves revealed significant differences in event-free survival rates among Lp(a) quartile groups ( P = .001). Multivariate Cox proportional hazards regression analysis indicated that serum Lp(a) level was an independent predictor of MACE either as a continuous variable (hazard ratio [HR]: 1.002, 95% confidence interval [CI]: 1.001-1.004; P = .009) or as a categorical variable (HR: 1.443, 95% CI: 1.074-1.937; P = .015). Furthermore, Lp(a) levels (as a variable) significantly improved the prognostic value for MACE. These findings suggest that Lp(a) measurement has value for cardiovascular risk stratification in patients with premature ACS.

Lipoprotein(a): An independent, genetic, and causal factor for cardiovascular disease and acute myocardial infarction

Lipoprotein(a) [Lp(a)] is a circulating lipoprotein, and its level is largely determined by variation in the Lp(a) gene (LPA) locus encoding apo(a). Genetic variation in the LPA gene that increases Lp(a) level also increases coronary artery disease (CAD) risk, suggesting that Lp(a) is a causal factor for CAD risk. Lp(a) is the preferential lipoprotein carrier for oxidized phospholipids (OxPL), a proatherogenic and proinflammatory biomarker. Lp(a) adversely affects endothelial function, inflammation, oxidative stress, fibrinolysis, and plaque stability, leading to accelerated atherothrombosis and premature CAD. The INTER-HEART Study has established the usefulness of Lp(a) in assessing the risk of acute myocardial infarction in ethnically diverse populations with South Asians having the highest risk and population attributable risk. The 2018 Cholesterol Clinical Practice Guideline have recognized elevated Lp(a) as an atherosclerotic cardiovascular disease risk enhancer for initiating or intensifying statin therapy.

Elevated lipoprotein (a) levels are associated with the presence and severity of coronary artery disease in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

The role of lipoprotein (a) [Lp(a)] in coronary artery diseases (CAD) with special clinical background such as type 2 diabetes mellitus (T2DM) has not been fully determined. The aim of the present study was to investigate the relation of Lp(a) to type 2 diabetic patients with or without CAD.

METHODS AND RESULTS

A total of 2040 consecutive patients with T2DM who received selective coronary angiography (CAG) due to angina-like chest pain were enrolled. The patients were subsequently divided into CAD and non-CAD groups according to the results of CAG. The severity of CAD was evaluated by the Gensini Score (GS), number of stenotic vessels, and history of myocardial infarction (MI). Data showed that Lp(a) levels were higher in the CAD group than in the non-CAD group (median: 15.00 mg/dL vs. 11.88 mg/dL, P = 0.025). The results from CAD subgroup analysis indicated that the patients with MI, multiple-vessel disease and high GS had higher Lp(a) levels compared with those in their matched subgroups (P < 0.05, respectively). After adjustment for confounders, Lp(a) levels were independently related to the presence and severity of CAD (CAD:OR = 1.564; MI:OR = 1.523; high GS:OR = 1.388; multiple-vessel disease:OR = 1.455; P < 0.05, respectively).

CONCLUSION

Elevated Lp(a) levels were independently associated with the presence and severity of CAD in patients with T2DM. More studies are necessary to confirm our findings.

Effect of dietary modification by calorie restriction on cholesterol levels in lipoprotein(a) and other lipoprotein classes

Background Dietary habits are associated with obesity which is a risk factor for coronary heart disease. The objective is to estimate the change of lipoprotein(a) and other lipoprotein classes by calorie restriction with obesity index and Framingham risk score. Methods Sixty females (56 ± 9 years) were recruited. Their caloric intakes were reduced during the six-month period, and the calorie from fat was not more than 30%. Lipoprotein profiles were estimated at baseline and after the six-month period of calorie restriction. Cholesterol levels in six lipoprotein classes (HDL, LDL, IDL, VLDL, chylomicron and lipoprotein(a)) were analysed by anion-exchange liquid chromatography. The other tests were analysed by general methods. Additionally, Framingham risk score for predicting 10-year coronary heart disease risk was calculated. Results Body mass index, waist circumference, insulin resistance, Framingham risk score, total cholesterol, LDL-cholesterol and IDL-cholesterol were significantly decreased by the calorie restriction, and the protein and cholesterol levels of lipoprotein(a) were significantly increased. The change of body mass index was significantly correlated with those of TC, VLDL-cholesterol and chylomicron-cholesterol, and that of waist circumference was significantly correlated with that of chylomicron-cholesterol. The change of Framingham risk score was significantly correlated with the change of IDL-C. Conclusion Obesity indexes and Framingham risk score were reduced by the dietary modification. Lipoprotein profile was improved with the reduction of obesity indexes, but lipoprotein(a) was increased. The changes of obesity indexes and Framingham risk score were related with those of triglyceride-rich lipoproteins, e.g. IDL, VLDL and CM.

The relationship between Lp(a) and CVD outcomes: a systematic review

Robust associations between lipoprotein(a) [Lp(a)] and CVD outcomes among general populations have been published in previous studies. However, associations in high risk primary prevention and secondary prevention populations are less well defined. In order to investigate this further, a systematic review was performed including prospective studies, which assessed the relationship between Lp(a) and CVD outcomes using multivariable analyses. Additional information was gathered on Lp(a) assays, multivariable modelling and population characteristics. Literature searches from inception up to December 2015 retrieved 2850 records. From these 60 studies were included. Across 39 primary prevention studies in the general population (hazard ratios ranged from 1.16 to 2.97) and seven high risk primary prevention studies (hazard ratios ranged from 1.01 to 3.7), there was evidence of a statistically significant relationship between increased Lp(a) and an increased risk of future CVD. Results in 14 studies of secondary prevention populations were also suggestive of a modest statistically significant relationship (hazard ratios ranged from 0.75 to 3.7).Therefore current evidence would suggest that increased Lp(a) levels are associated with modest increases in the risk of future CVD events in both general and higher risk populations. However, further studies are required to confirm these findings.