JCL roundtable-Lipoprotein(a): The emerging risk factor

Supporting evidence for lipoprotein(a) measurements in clinical practice

High levels of lipoprotein(a) [Lp(a)] are causal for development of atherosclerotic cardiovascular disease and highly regulated by genetics. Levels are higher in Blacks compared to Whites, and in women compared to men. Lp(a)'s main protein components are apolipoprotein (apo) (a) and apoB100, the latter being the main component of Low-Density Lipoprotein (LDL) particles. Studies have identified Lp(a) to be associated with inflammatory, coagulation and wound healing pathways. Lack of validated and accepted assays to measure Lp(a), risk cutoff values, guidelines for diagnosis, and targeted therapies have added challenges to the field. Scientific efforts are ongoing to address these, including studies evaluating the cardiovascular benefits of decreasing Lp(a) levels with targeted apo(a) lowering treatments. This review will provide a synopsis of evidence-based effects of high Lp(a) on disease presentation, highlight available guidelines and discuss promising therapies in development. We will conclude with current clinical information and future research needs in the field.

Use of Lipoprotein(a) in clinical practice: A biomarker whose time has come. A scientific statement from the National Lipid Association

Lipoprotein(a) [Lp(a)] is a well-recognized, independent risk factor for atherosclerotic cardiovascular disease, with elevated levels estimated to be prevalent in 20% of the population. Observational and genetic evidence strongly support a causal relationship between high plasma concentrations of Lp(a) and increased risk of atherosclerotic cardiovascular disease-related events, such as myocardial infarction and stroke, and valvular aortic stenosis. In this scientific statement, we review an array of evidence-based considerations for testing of Lp(a) in clinical practice and the utilization of Lp(a) levels to inform treatment strategies in primary and secondary prevention.

Expert position statements: comparison of recommendations for the care of adults and youth with elevated lipoprotein(a)

PURPOSE OF REVIEW

Summarize recent recommendations on clinical management of adults and youth with elevated lipoprotein(a) [Lp(a)] who are at-risk of or affected by cardiovascular disease (CVD).

RECENT FINDINGS

There is ample evidence to support elevated Lp(a) levels, present in approximately 20% of the general population, as a causal, independent risk factor for CVD and its role as a significant risk enhancer. Several guidelines and position statements have been published to assist in the identification, treatment and follow-up of adults with elevated levels of Lp(a). There is growing interest in Lp(a) screening and strategies to improve health behaviors starting in youth, although published recommendations for this population are limited. In addition to the well established increased risk of myocardial infarction, stroke and valvular aortic stenosis, data from the coronavirus pandemic suggest adults with elevated Lp(a) may have a particularly high-risk of cardiovascular complications. Lp(a)-specific-lowering therapies are currently in development. Despite their inability to lower Lp(a), use of statins have been shown to improve outcomes in primary and secondary prevention.

SUMMARY

Considerable differences exist amongst published guidelines for adults on the use of Lp(a) in clinical practice, and recommendations for youth are limited. With increasing knowledge of Lp(a)'s role in CVD, including recent observations of COVID-19-related risk of cardiovascular complications, more harmonized and comprehensive guidelines for Lp(a) in clinical practice are required. This will facilitate clinical decision-making and help define best practices for identification and management of elevated Lp(a) in adults and youth.

Effect of different types and dosages of statins on plasma lipoprotein(a) levels: A network meta-analysis

BACKGROUND AND AIM

Studies differ with respect to the effects of statins and their on lipoprotein(a)[Lp(a)] levels. The aim of the present study was to resolve these differences by determining the effect of various types and dosages of statins on Lp(a) levels.

METHODS

We searched PubMed, Embase and the Cochrane library for randomized controlled trials (RCTs) investigating the efficacy of statins on plasma Lp(a) levels. Study selection, data extraction and risk of bias assessment were conducted independently by four authors. We conducted pairwise meta-analysis and network meta-analysis (NMA). Consistency models were applied to NMA and the ranking probabilities for each treatment's efficacy were calculated. Node-splitting analysis was used to test inconsistency. This study was registered with PROSPERO, number CRD42020167612.

RESULTS

Twenty RCTs with 23,605 participants were included, involving 11 interventions. Most of the included studies presented some risks of bias, especially risks of performance and detection bias. In the pairwise meta-analysis, pooled results showed a small but statistically significant difference between high-intensity rosuvastatin and placebo on Lp(a) levels (MD = 1.81, 95 % CI [0.43, 3.19], P = 0.01). In the NMA, different types and dosages of statins showed no significant effect on the level of Lp(a), and there was no obvious difference between them. Subgroup analysis based on different populations and treatment durations did not provide any statistically significant findings about different statins on Lp(a) levels. Node-splitting analysis showed that no significant inconsistency existed (P > 0.05).

CONCLUSIONS

Statins have no clinically significant effect on Lp(a) levels, and there is no significant difference in the effect on Lp(a) levels between different types and dosages of statins. Moderate-intensity pitavastatin tended to have the best effect on reducing Lp(a) levels; nevertheless, it was insignificant. Our findings highlight the necessity for further study of the effect of statins on Lp(a) levels in future studies.

Familial hypercholesterolemia and elevated lipoprotein(a): double heritable risk and new therapeutic opportunities

There is compelling evidence that the elevated plasma lipoprotein(a) [Lp(a)] levels increase the risk of atherosclerotic cardiovascular disease (ASCVD) in the general population. Like low-density lipoprotein (LDL) particles, Lp(a) particles contain cholesterol and promote atherosclerosis. In addition, Lp(a) particles contain strongly proinflammatory oxidized phospholipids and a unique apoprotein, apo(a), which promotes the growth of an arterial thrombus. At least one in 250 individuals worldwide suffer from the heterozygous form of familial hypercholesterolemia (HeFH), a condition in which LDL-cholesterol (LDL-C) is significantly elevated since birth. FH-causing mutations in the LDL receptor gene demonstrate a clear gene-dosage effect on Lp(a) plasma concentrations and elevated Lp(a) levels are present in 30-50% of patients with HeFH. The cumulative burden of two genetically determined pro-atherogenic lipoproteins, LDL and Lp(a), is a potent driver of ASCVD in HeFH patients. Statins are the cornerstone of treatment of HeFH, but they do not lower the plasma concentrations of Lp(a). Emerging therapies effectively lower Lp(a) by as much as 90% using RNA-based approaches that target the transcriptional product of the LPA gene. We are now approaching the dawn of an era, in which permanent and significant lowering of the high cholesterol burden of HeFH patients can be achieved. If outcome trials of novel Lp(a)-lowering therapies prove to be safe and cost-effective, they will provide additional risk reduction needed to effectively treat HeFH and potentially lower the CVD risk in these high-risk patients even more than currently achieved with LDL-C lowering alone.

Lipoprotein apheresis is an optimal therapeutic option to reduce increased Lp(a) levels

BACKGROUND

Lipoprotein(a) (Lp(a)) is a genetic risk factor for cardiovascular disease (CVD) and is associated with the induction and sustaining of atherosclerotic cardiovascular diseases (ASCVD). Since 2008 Lp(a) along with progressive CVD has been approved as an indication for regular lipoprotein apheresis (LA) in Germany. The German Lipoprotein Apheresis Registry (GLAR) has been initiated to provide statistical evidence for the assessment of extracorporeal procedures to treat dyslipidemia for both LDL-cholesterol (LDL-C) and Lp(a). The GLAR now allows prospective investigations over a 5-year period about annual incidence rates of cardiovascular events. Here Lp(a) patients (LDL-C < 100 mg/dl; Lp(a) > 60 mg/dl or >120 nmol/l) showed the same reduction of major coronary (83%) and non-coronary events (63%) as had been formerly shown in the Pro(a)LiFe study. However, Lp(a) is not only an apolipoprotein(a) (apo(a)) and LDL-C containing particle, which is covalently bound to a LDL-C core by a disulphide bridge. The composition of this particle, inter alia containing oxidized phospholipids, gives pro-atherosclerotic, pro-inflammatory, and pro-thrombotic properties, inducing atherosclerotic processes mainly in the arterial wall. However, recent investigations have shown that a reduction of inflammatory settings without LDL-C or Lp(a) reduction may reduce ASCVD events. Lipoprotein apheresis (LA) could not only reduce LDL-C and Lp(a) in parallel, but also different inflammatory and coagulation parameters. In summary lipoprotein apheresis is not only anti-atherosclerotic, but also anti-inflammatory and anti-thrombotic and therefore an ideal treatment option with respect to the shown reduction of major adverse coronary events (MACE) and major adverse non-coronary events (MANCE) by reducing Lp(a) levels.