Lipoprotein (a) [Lp (a)] is a low density lipoprotein (LDL) disulfide-linked to apolipoprotein (a) [apo (a)] and considered to be an independent risk factor for atherosclerotic cardiovascular disease. Apo (a) has a high homology with plasminogen, which has stimulated a lot of interest in the mechanism of atherogenicity and thrombogenicity of this lipoprotein. Recent advances in this mechanism were reviewed. We are still unclear about the physiological role of Lp (a). This research aspect must receive attention in the future. Furthermore, the most pressing need is for drugs that will lower serum Lp (a) concentrations.
Patients with symptomatic peripheral arterial disease (PAD) are at a very high risk of cardiovascular morbidity and mortality. Elevated lipoprotein(a) levels have been shown to be a risk factor for coronary artery disease (CAD) and stroke. More recently elevated lipoprotein(a) levels have also been demonstrated to be associated with prevalent and incident PAD, and even may be a stronger risk factor for PAD compared with CAD. Lipoprotein apheresis is currently the only efficient way to lower lipoprotein(a) levels. Lipoprotein(a) apheresis has been shown to reduce major coronary events in patients with CAD. There is increasing evidence that lipoprotein(a) apheresis also reduces the rate of major adverse limb events such as peripheral revascularizations and amputations in PAD patients, and improves symptoms of PAD such as pain on exertion. This review summarizes the current knowledge on the clinical role of lipoprotein(a) for PAD and the disease-specific effect of lipoprotein(a) apheresis, and suggests indications for screening for and treating of elevated lipoprotein(a) levels in patients with PAD.
In the middle of the 1990s the interest in Lp(a) vanished after a few badly performed studies almost erased Lp(a) from the map of biological targets. However, since roughly 10 years the interest has begun to grow again mainly for two reasons: first, genetic studies using easily accessible and high-throughput techniques for genotyping of single-nucleotide polymorphisms (SNPs) have allowed large studies in patients with cardiovascular disease and controls to be performed. This strengthened the earlier findings on a copy number variation in the LPA gene and its association with cardiovascular outcomes. Second, new therapies are on the horizon raising strong and justified hope that in a few years drugs will become available which tremendously lower Lp(a) concentrations. This review article should provide an introduction to the genetic determination of Lp(a) concentrations and considerations whether Lp(a) concentrations or genetic variants are important for the prediction of cardiovascular risk.
Elevated levels of lipoprotein(a) (Lp(a)) contribute to the risk of early and severe cardiovascular disease (CVD) and Lp(a) is acknowledged as a risk factor to be included in risk assessment. The established lipid-modifying medical therapies do not lower Lp(a) except niacin but no data of endpoint trials are available. Of the new lipid-modifying drugs a few have some impact on Lp(a). Whether the Lp(a) lowering effect contributes to the reduction of CVD events would have to be shown in Lp(a) dedicated trials. None of the available agents is indicated to lower Lp(a). Lipoprotein apheresis lowers levels of Lp(a) significantly by >60% per treatment. Trial data and data of the German Lipoprotein Apheresis Registry show that regular apheresis reduces cardiovascular events. The Apo(a) antisense oligonucleotide is the only approach to specifically lower Lp(a). The IONIS-APO(a)Rx phase 1 and 2 trials showed very substantial decreases of Lp(a) and good tolerability. The hepatospecific variant IONIS-APO(a)-LRx is 30 times more potent. The results of the IONIS-APO(a)-LRx phase 2 trial were presented recently. The highest dosages reduced Lp(a) by 72 and 80%; in about 81 and 98% Lp(a) levels <50 mg/dl were achieved. Tolerability and safety were confirmed, whereby injection site reactions were the most common side effects. This raises hope that the planned phase 3 trial will reproduce these findings and show a reduction of cardiovascular events.
Lipoprotein(a) (Lp(a)) is an internationally recognized atherogenic risk factor which is inherited and not changed by nutrition or physical activity. At present, only proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors may modestly decrease its concentration (but not in all patients)—leading to a certain decrease in cardiovascular events (CVE) in controlled studies. However, at present an elevation of Lp(a) is not a generally accepted indication for their use. More effective is lipoprotein apheresis (LA) therapy with respect to both lowering Lp(a) levels and reduction of CVE. In the future, an antisense oligonucleotide against apolipoprotein(a) will probably be available. Atherosclerosis in patients with an elevation of Lp(a) may affect several vessel regions (carotids, aorta, coronaries, leg arteries). Thus, Lp(a) should be measured in high-risk patients. These patients are usually cared for by their family doctors and by other specialists who should closely cooperate. Lipidologists should decide whether costly therapies like PCSK9 inhibitors or LA should be started. The main aim of current therapy is to optimize all other risk factors (LDL cholesterol, hypertension, diabetes mellitus, body weight, renal insufficiency). Patients should be regularly monitored (lab data, heart, arteries). This paper describes the duties of physicians of different specialties when caring for patients with high Lp(a) concentrations.
Lipoprotein(a) (Lp(a)) is an internationally accepted independent atherogenic risk factor. Details about its synthesis, many aspects of composition and clearance from the bloodstream are still unknown. LDL receptor (LDLR) (and probably other receptors) play a role in the elimination of Lp(a) particles. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors increase the number of available LDLRs and in this way very effectively reduce the LDL cholesterol (LDL-C) concentrations. As shown in controlled studies using PCSK9 inhibitors, Lp(a) levels are decreased by 20 to 30%, though in some patients no effect was observed. So far, it has not been clarified whether this decrease is associated with an effect on the incidence of cardiovascular events (CVEs). In two recently published well-performed secondary prevention studies (FOURIER with evolocumab, ODYSSEY OUTCOMES with alirocumab) baseline Lp(a) levels were shown to have an impact on CVEs independently of baseline LDL-C concentrations. The rather modest PCSK9 inhibitor-induced decrease of Lp(a) was associated with a reduction of CVEs in both studies, even after adjusting (ODYSSEY OUTCOMES) for demographic variables (age, sex, race, region), baseline Lp(a), baseline LDL-C, change in LDL-C, and clinical variables (time from acute coronary syndrome, body mass index, diabetes, smoking history). The largest decrease of CVEs was seen in patients with relatively low concentrations of both LDL-C and Lp(a) (FOURIER). These findings will probably have an influence on the use of PCSK9 inhibitors in patients with high Lp(a) concentrations.
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.
The structural similarity with plasminogen as well as thrombogenic and atherogenic in vitro functions raise the question if lipoprotein(a) (Lp(a)) is a risk factor for venous thromboembolism (VTE) and ischemic stroke. Numerous case–control and prospective studies using different cut-off values to define high Lp(a) generated conflicting evidence for both VTE and ischemic stroke. Several meta-analyses demonstrated independent associations of elevated Lp(a) with a history of VTE or ischemic stroke. However, the evidence of prospective studies for associations of Lp(a) with incident stroke or recurrent VTE remains inconclusive. For ischemic stroke, data suggest that Lp(a) increases the risk of large-artery atherosclerosis stroke, but not cardioembolic or lacunar stroke. Lp(a) may increase the risk of VTE in the presence of additional thrombophilic risk factors. Larger cohort studies are needed to elaborate the importance of higher Lp(a) cut-offs and interactions with other risk factors and subgroups of stroke or VTE. The value of Lp(a) to estimate residual vascular risk after the first thromboembolic event remains to be adequately explored.
Lipoprotein(a) (Lp(a)) is an independent cardiovascular risk factor playing a causal role for atherosclerotic cardiovascular disease (ASCVD). Early or progressive ASCVD or a familial predisposition are key findings which can be associated with Lp(a)-hyperlipoproteinemia (Lp(a)-HLP). The German guideline for the indication of lipoprotein apheresis in patients with Lp(a)-HLP has proved to be of value to identify patients at highest risk, using the composite of a Lp(a) threshold >60 mg/dl (>120 nmol/l) and clinical ASCVD progression despite effective LDL-C lowering therapy. In particular for such patients it appears to be plausible that Lp(a)-associated risk would increase cardiovascular mortality as the most important part of total mortality in Western populations. By the majority of existing investigations an association of Lp(a) concentration on total or cardiovascular mortality was demonstrated. However, inconsistency in the findings between studies exists without a clear trend for any study feature to explain this. Genetic homogeneity of the population, long-term follow-up, and clinically guided selection of patients might be important to further clarify the impact of Lp(a) concentration on progression of ASCVD, and finally total or cardiovascular mortality. LDL and Lp(a) particles exhibit a mutual effect modification on related ASCVD risk. Therefore, LDL-C levels and concomitant LDL-C lowering treatment must be considered in this context. Prospective evaluation is needed to document that specific Lp(a)-lowering additional to targeted LDL-C lowering will in fact reduce cardiovascular or total mortality.
A high level of lipoprotein(a) (Lp(a)) is recognized as an independent and additional cardiovascular risk factor contributing to the risk of early onset and progressive course of cardiovascular disease (CVD). All lipid lowering medications in use mainly lower low density lipoprotein-cholesterol (LDL-c) with no or limited effect on levels of Lp(a). Niacin, the only component lowering Lp(a), is firstly often poorly tolerated and secondly not available anymore in many countries. A level of <50 mg/dl was recommended recently as the cut off level for clinical use and decision making. Since lipoprotein apheresis (LA) lowers not only LDL-c but also Lp(a) significantly, its use is recommended in some countries in very high-risk patients with early or progressive CVD. Retrospective analyses show that regular LA improves the course of CVD. This is supported by a recent prospective observational trial and data of the German Lipoprotein Apheresis Registry. Despite many treatment options, all too often it is not possible to reduce LDL-c levels to target and to reduce Lp(a) levels sustainably at all. Therefore, new drug therapies are awaited. Some of the lipid modifying drugs in development lower Lp(a) to some extent in addition to LDL-c; the only specific approach is the apoprotein(a) antisense oligonucleotide. Currently LA is the standard of care as a last resort treatment in high-risk patients with elevated Lp(a) and severe CVD despite optimal control of all other cardiovascular risk factors.
Background: In recent years the Federal Joint Committee (G-BA), a paramount decision-making body of the German health care system required a reassessment of the approval of chronic lipoprotein apheresis therapy for regular reimbursement. Since 2005 an interdisciplinary German apheresis working group has been established by members of both German Societies of Nephrology. In 2009 the working group completed the indication for lipoprotein apheresis with respect to current cardiovascular guidelines and current scientific knowledge for the registry. In 2011 the German Lipoprotein Apheresis Registry (GLAR) was launched and data acquired over nearly 5 years can now be reported. Methods and results: All data were collected and analyzed during the time period 2012-2015. Over this time interval, 68 German apheresis centers collected retrospective and prospective observational data of 1.283 patients undergoing lipoprotein apheresis (LA) treatment of high LDL-cholesterol (LDL-C) levels and/or high lipoprotein(a) (Lp(a)) levels suffering from progressive cardiovascular disease (CVD). A total of 15,167 documented LA treatments were investigated. All patients treated by LA exhibited a median LDL-C reduction rate of 68.6%, and a median Lp(a) reduction rate of 70.4%. Analogue to the Pro(a) LiFe pattern, patient data were analyzed and compared with respect to the incidence rate of coronary events MACE) 1 and 2 years before the start of LA treatment (y-2 and y-1) and prospectively one year on LA treatment (y+1). During the first year of LA treatment a MACE reduction of 97% was be observed. In the years considered, LA treatment side effects occurred at a low rate (ca. 5%) and mainly comprised puncture problems. Conclusions: For the first time data generated by the GLAR shows that LA lowers the incidence rate of cardiovascular events in patients with high LDL-C and/or high Lp(a) levels, progressive CVD and maximally tolerated lipid lowering medication. In addition LA treatments were found to be safe, exhibiting a low rate of side effects. (C) 2017 Elsevier B.V. All rights reserved.
General lipoprotein (Lp) (a) screening can help to identify patients at high risk for cardiovascular disease. Non-invasive methods allow early detection of clinically asymptomatic incipient atherosclerotic disease. Medical treatment options are still unsatisfactory. Lp(a) apheresis is an established treatment in Germany for secondary prevention of progressive cardiovascular disease. Statin-based lowering of LDL cholesterol and thrombocyte aggregation inhibitors still represent the basis of medical treatment. Target levels for LDL-cholesterol should be modified in patients with hyperlipoproteinemia (a).
Lipoprotein(a) (Lp(a)) is an independent cardiovascular risk factor playing a causal role for atherosclerotic cardiovascular disease (CVD). Lipoprotein apheresis (LA) is a safe well-tolerated outpatient treatment to lower LDL-C and Lp(a) by 60–70%, and is the ultimate escalating therapeutic option in patients with hyperlipoproteinemias (HLP) involving LDL particles. Major therapeutic effect of LA is preventing cardiovascular events. Lp(a)-HLP associated with progressive CVD has been approved as indication for regular LA in Germany since 2008. The Pro(a)LiFe-study investigated with a prospective multicenter design the long-term preventive effect of LA on incidence rates of cardiovascular events prospectively over a period of 5 years in 170 consecutive patients who commenced regular LA. During a median period of 4.7 years of the pre-LA period, Lp(a) associated progressive CVD became apparent. Apolipoprotein(a) (apo(a)) isoforms and polymorphisms at the apo(a) gene ( LPA ) were analyzed to assess hypothetical clinical correlations. 154 patients (90.6%) completed 5‑years follow-up. Significant decline of the mean annual major adverse cardiac event (MACE) rate was observed from 0.41 ± 0.45 two years prior to regular LA to 0.06 ± 0.11 during 5 years with regular LA ( p < 0.0001). 95.3% of patients expressed at least one small apo(a) isoform. Calculation of isoform specific concentrations allowed to confirm the equivalence of 60 mg/dl or 120 nmol/l as Lp(a) thresholds of the German LA guideline. Results of 5 years prospective follow-up confirmed that LA has a lasting effect on prevention of cardiovascular events in patients with Lp(a)-HLP and afore progressive CVD.
This Editorial is part of the special issue “Lp(a) – the underestimated cardiovascular risk factor”.
Lipoprotein (a) (Lp (a)) is one risk factor for the development of cardiovascular diseases. Several studies have shown that Lp (a) hyperlipoproteinaemia has a particular influence on the development of coronary heart disease (CHD). A retrospective single-centre observation study was performed to evaluate the effectiveness of lipid apheresis on the basis of consecutively performed percutaneous coronary interventions (PCI) in patients with high Lp (a) values and angiographically documented CHD.
In contrast to existing EAS/ESC guidelines on the management of lipid disorders, current recommendations from nephrological societies are very conservative and restrictive with respect to any escalation of lipid lowering/statin therapy. Furthermore, lipoprotein(a) (Lp(a)) – an established cardiovascular risk factor – has not even been mentioned. While a number of retrospective and prospective studies suggested that Lp(a) has relevant predictive value and might have – at least in stage-3 chronic kidney disease (CKD) – the same negative effects if draged along in non-CKD patients, there is no guidance on diagnostic or therapeutic procedures. The persistent lack of recognition automatically leads to therapeutic nihilism, which might pose a number of relatively young patients to a significantly increased risk for adverse cardiovascular events. Further evaluation of Lp(a) in CKD is very important to provide appropriate treatment to patients with high Lp(a) levels, even in the presence of CKD.
Ischemic heart disease is the main cause of death worldwide and it is accelerated by increased low-density lipoprotein (LDL) cholesterol (LDL-C) and/or lipoprotein (a) (Lp(a)) concentrations. Proprotein convertase subtilisin/kexin type 9 (PCSK9) alters both LDL-C and in part Lp(a) concentrations through its ability to induce degradation of the LDL receptor (LDLR). PCSK9, however, has additional targets which are potentially involved in lipid metabolism regulation such as the very low density lipoprotein receptor (VLDL), CD36 (cluster of differentiation 36) and the epithelial cholesterol transporter (NPC1L1) and it affects expression of apolipoprotein B48. The PCSK9 activity is tightly regulated at several levels by factors influencing its transcription, secretion, or by extracellular inactivation and clearance. Many comorbidities (kidney insufficiency, hypothyreoidism, hyperinsulinemia, inflammation) modify PCSK9 expression and release. Two humanized antibodies directed against extracellular PCSK9 received approval by the European and US authorities and additional PCSK9 directed therapeutics (such as silencing RNA) are already in clinical trials. Their results demonstrate a significant reduction in both LDL-C and Lp(a) concentrations – independent of the concomitant medication – and one of them reduced plaque size in high risk cardiovascular patients; results of two ongoing large clinical endpoints studies are awaited. In this review, we summarize and discuss the recent biological data on PCSK9, the regulation of PCSK9, and finally briefly summarize the data of recent clinical studies in the context of lipid metabolism.
