The role of lipoprotein (a) in primary and secondary cardiovascular disease prevention: a systematic review of epidemiological studies

A synthesis of pathways linking diet, metabolic risk and cardiovascular disease: a framework to guide further research and approaches to evidence-based practice

Cardiovascular disease (CVD) is the most common non-communicable disease occurring globally. Although previous literature has provided useful insights into the important role that diet plays in CVD prevention and treatment, understanding the causal role of diets is a difficult task considering inherent and introduced weaknesses of observational (e.g. not properly addressing confounders and mediators) and experimental research designs (e.g. not appropriate or well designed). In this narrative review, we organised current evidence linking diet, as well as conventional and emerging physiological risk factors, with CVD risk, incidence and mortality in a series of diagrams. The diagrams presented can aid causal inference studies as they provide a visual representation of the types of studies underlying the associations between potential risk markers/factors for CVD. This may facilitate the selection of variables to be considered and the creation of analytical models. Evidence depicted in the diagrams was systematically collected from studies included in the British Nutrition Task Force report on diet and CVD and database searches, including Medline and Embase. Although several markers and disorders linked to conventional and emerging risk factors for CVD were identified, the causal link between many remains unknown. There is a need to address the multifactorial nature of CVD and the complex interplay between conventional and emerging risk factors with natural and built environments, while bringing the life course into the spotlight.

Prediction of 10-year cardiovascular disease risk by diabetes status and lipoprotein-a levels; the HellenicSCORE II

BACKGROUND

The aim of this study was to develop an updated model to predict 10-year cardiovascular disease (CVD) risk for Greek adults, i.e., the HellenicSCORE II+, based on smoking, systolic blood pressure (SBP), total and high-density-lipoprotein (HDL) cholesterol levels, and stratified by age group, sex, history of diabetes, and lipoprotein (Lp)-a levels.

METHODS

Individual CVD risk scores were calculated through logit-function models using the beta coefficients derived from SCORE2. The Attica study data were used for the calibration (3,042 participants, aged 45 (14) years; 49.1% men). Discrimination ability of the HellenicSCORE II+ was assessed using C-index (range 0-1), adjusted for competing risks.

RESULTS

The mean HellenicSCORE II+ score was 6.3% (95% confidence interval (CI) 5.9% to 6.6%) for men and 3.7% (95% CI 3.5% to 4.0%) for women (p < 0.001), and were higher compared to the relevant SCORE2; 23.5% of men were classified as low risk, 40.2% as moderate, and 36.3% as high risk, whereas the corresponding percentages for women were 56.2%, 18.6%, and 25.2%. C-statistic index was 0.88 for women and 0.79 for men when the HellenicSCORE II+ was applied to the Attica study data, suggesting very good accuracy. Stratified analysis by Lp(a) levels led to a 4% improvement in correct classification among participants with high Lp(a).

CONCLUSION

HellenicSCORE II+ values were higher than SCORE2, confirming that the Greek population is at moderate-to-high CVD risk. Stratification by Lp(a) levels may assist in better identifying individuals at high CVD risk.

Association of statin use and increase in lipoprotein(a): a real-world database research

BACKGROUND

There is an increased concern that statins may have an unintended effect of elevated lipoprotein(a) [Lp(a)]. We conducted a large sample real-world study to test the association.

METHODS

This retrospective cohort study was conducted using data from an integrated SuValue database, which includes 221 hospitals across China covering more than 200,000 of population with longitudinal follow-up to 10 years. Propensity score matching was applied to identify two comparable cohorts with statin users and non-statin users. Detailed follow-up information such as Lp(a) levels were extracted. The hazard ratio was calculated on Lp(a) changes based on the statin usage cohorts. Detailed subgroup and different characteristic cohorts' analyses were also conducted.

RESULTS

After baseline propensity score matching, a total of 42,166 patients were included in a 1:1 matched ratio between statin users and non-statin users. In the case of no difference in low density lipoprotein (LDL-C), Lp(a) was increased significantly with the use of statins (adjusted HR 1.47; 95% confidence interval [CI] 1.43-1.50). Lp(a) increase was observed in various subgroup analyses and different cohorts. The dose intensity of statin was positively associated with the evaluated Lp(a) level.

CONCLUSION

The use of statins was associated with an increased risk of Lp(a) elevation compared with non-statin use counterparts. The clinical relevance of these increases needs to be addressed in surrogate marker trials and/or large, cardiovascular outcomes trials.

Lipoprotein(a) and its Significance in Cardiovascular Disease: A Review

Importance

Lipoprotein(a) (Lp[a]) is a low-density lipoprotein (LDL) cholesterol-like particle bound to apolipoprotein(a). This novel marker of cardiovascular disease acts through induction of vascular inflammation, atherogenesis, calcification, and thrombosis. While an absolute risk threshold remains to be universally accepted, an estimated 20% to 25% of the global population have Lp(a) levels of 50 mg/dL or higher, a level noted by the European Atherosclerosis Society to confer increased cardiovascular risk.

Observations

Compelling evidence from pathophysiological, observational, and genetic studies suggest a potentially causal association between high Lp(a) levels, atherosclerotic cardiovascular disease, and calcific aortic valve stenosis. Additional evidence has demonstrated that elevated Lp(a) levels are associated with a residual cardiovascular risk despite traditional risk factor optimization, including LDL cholesterol reduction. These findings have led to the formulation of the Lp(a) hypothesis, namely that Lp(a) lowering leads to cardiovascular risk reduction, intensifying the search for Lp(a)-reducing therapies. The ineffectiveness of lifestyle modification, statins, and ezetimibe to lower Lp(a); the modest Lp(a) reduction with proprotein convertase subtilisin/kexin type 9 inhibitors; the adverse effect profile and unclear cardiovascular benefit of pharmacotherapies such as niacin and mipomersen; and the impracticality of regular lipoprotein apheresis represent major challenges to currently available therapies. Nevertheless, emerging nucleic acid-based therapies, such as the antisense oligonucleotide pelacarsen and the small interfering RNA olpasiran, are generating interest because of their potent Lp(a)-lowering effects. Assessment of new-onset diabetes in patients achieving very low Lp(a) levels will be important in future trials.

Conclusions and Relevance

Epidemiologic and genetic studies suggest a potentially causal association between elevated Lp(a) levels, atherosclerotic cardiovascular disease, and aortic valve stenosis. Emerging nucleic acid-based therapies have potent Lp(a)-lowering effects and appear safe; phase 3 trials will establish whether they improve cardiovascular outcomes.

Antisense lipoprotein[a] therapy: State-of-the-art and future perspectives

Several lines of evidence now attest that lipoprotein[a] (Lp[a]) is a significant risk factor for many cardiovascular disorders. This enigmatic lipoprotein, composed of a single copy of apolipoprotein B (apoB) and apolipoprotein[a] (apo [a]), expresses peculiar metabolism, virtually independent from lifestyle interventions. Several therapeutic options have hence been proposed for lowering elevated Lp[a] values, with or without concomitant effect on low density lipoprotein (LDL) particles, mostly encompassing statins, ezetimibe, nicotinic acid, lipoprotein apheresis, and anti-PCSK9 monoclonal antibodies. Since all these medical treatments have some technical and clinical drawbacks, a novel strategy is currently being proposed, based on the use of antisense apo[a] and/or apoB inhibitors. Although the role of these agents in hypercholesterolemic patients is now nearby entering clinical practice, the collection of information on Lp[a] is still underway. Preliminary evidence would suggest that apo[a] antisense therapy seems more appropriate in patients with isolated Lp[a] elevations, while apoB antisense therapy is perhaps more advisable in patients with isolated LDL elevations. In patients with concomitant elevations of Lp[a] and LDL, either combining the two apo[a] and apoB antisense therapies (a strategy which has never been tested), or the combination of well-known and relatively inexpensive drugs such as statins with antisense apo[a] inhibitors can be theoretically suggested. The results of an upcoming phase 3 study with antisense apo[a] inhibitors will hopefully provide definitive clues as to whether this approach may become the standard of care in patients with increased Lp[a] concentrations.

Achieving low-density lipoprotein cholesterol targets as assessed by different methods in patients with familial hypercholesterolemia: an analysis from the HELLAS-FH registry

Background

Familial hypercholesterolemia (FH) is characterized by elevated low-density lipoprotein cholesterol (LDL-C) levels and increased cardiovascular disease (CVD) risk. FH patients often have increased lipoprotein(a) [Lp(a)] levels, which further increase CVD risk. Novel methods for accurately calculating LDL-C have been proposed.

Methods

Patients with FH were recruited by a network of Greek sites participating in the HELLAS-FH registry. LDL-C levels were calculated using the Friedewald (LDL-C_F) and the Martin/Hopkins (LDL-C_M/H) equations as well as after correcting LDL-C_M/H for Lp(a) levels [LDL-C_Lp(a)corM/H]. The objective was to compare LDL-C levels and target achievement as estimated by different methods in FH patients.

Results

This analysis included 1620 patients (1423 adults and 197 children). In adults at diagnosis, LDL-C_F and LDL-C_M/H levels were similar [235 ± 70 mg/dL (6.1 ± 1.8 mmol/L) vs 235 ± 69 mg/dL (6.1 ± 1.8 mmol/L), respectively; P = NS], while LDL-C_Lp(a)corM/H levels were non-significantly lower than LDL-C_F [211 ± 61 mg/dL (5.5 ± 1.6 mmol/L); P = 0.432]. In treated adults (n = 966) both LDL-C_F [150 ± 71 mg/dL (3.9 ± 1.8 mmol/L)] and LDL-C_M/H levels [151 ± 70 mg/dL (6.1 ± 1.8 mmol/L); P = 0.746] were similar, whereas LDL-C_Lp(a)corM/H levels were significantly lower than LDL-C_F [121 ± 62 mg/dL (3.1 ± 1.6 mmol/L); P < 0.001]. Target achievement as per latest guidelines in treated patients using the LDL-C_M/H (2.5%) and especially LDL-C_Lp(a)corM/H methods (10.7%) were significantly different than LDL-C_F (2.9%; P < 0.001).

In children, all 3 formulas resulted in similar LDL-C levels, both at diagnosis and in treated patients. However, target achievement by LDL-C_F was lower compared with LDL-C_M/H and LDL-C_Lp(a)corM/H methods (22.1 vs 24.8 vs 33.3%; P < 0.001 for both comparisons).

Conclusion

LDL-C_Lp(a)corM/H results in significantly lower values and higher target achievement rate in both treated adults and children. If validated in clinical trials, LDL-C_Lp(a)corM/H may become the method of choice to more accurately estimate ‘true’ LDL-C levels in FH patients.