Comparison of different Lp (a) elimination techniques: A retrospective evaluation

Oxidised LDL and Anti-Oxidised LDL Antibodies Are Reduced by Lipoprotein Apheresis in a Randomised Controlled Trial on Patients with Refractory Angina and Elevated Lipoprotein(a)

Aims: An abundance of epidemiological evidence demonstrates that elevated lipoprotein(a) (Lp(a)) represents a significant contributing risk factor towards the development of cardiovascular disease. In particular, raised Lp(a) may play a mechanistic role in patients with refractory angina. Studies have also shown a correlation between oxidised LDL (oxLDL) levels and atherosclerotic burden as well as rates of cardiovascular events. Antibodies against oxLDL (anti-oxLDL) are involved in the removal of oxLDL. Lipoprotein apheresis (LA), which removes lipoproteins using extra-corporeal processes, is an established means of reducing Lp(a), and thereby reduces cardiovascular events. The aim of this study was to investigate the effect of LA on oxLDL and anti-oxLDL levels amongst those with refractory angina in the context of raised Lp(a). Methods: We performed a sub-study within a randomised controlled crossover trial involving 20 patients with refractory angina and raised Lp(a) > 500 mg/L, comparing the effect of three months of blinded weekly LA or sham, followed by crossover to the opposite study arm. We utilized enzyme-linked immunosorbent assays (ELISA) to quantify oxLDL and IgG/ IgM anti-oxLDL antibody levels at baseline and following three months of active LA or sham sessions. Results: Following three months of LA, there was a 30% reduction in oxLDL from 0.37 ± 0.06 to 0.26 ± 0.04 with a mean drop of -0.11 units (U) (95% CI -0.13, -0.09) compared to no significant change with sham therapy (p < 0.0001 between treatment arms). LA also led to a 22% reduction in levels of IgG and IgM anti-oxLDL, again with no significant change demonstrated during sham (p = 0.0036 and p = 0.012, respectively, between treatment arms). Conclusion: Amongst patients with refractory angina in the context of elevated Lp(a), LA significantly lowers levels of oxLDL and anti-oxLDL antibodies, representing potential mechanisms by which LA yields symptomatic and prognostic benefits in this patient cohort.

Elevated Lipoprotein A in South Asians and the Associated Risk of Cardiovascular Disease: A Systematic Review

BACKGROUND

South Asians have a premature risk of cardiovascular disease and increased lipoprotein A which enhances their risk.

METHODS

This systematic review evaluates the role of elevated lipoprotein A in cardiovascular disease risk for South Asians. It discusses the pathophysiology, clinical studies, and treatment of elevated lipoprotein A using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses method.

RESULTS

A total of 72 articles was incorporated which consisted of clinical studies, case-control and cohort studies, meta-analysis, reviews, and editorials. Cardiovascular disease and myocardial infarction occurs prematurely in South Asians, which is further enhanced with an elevated lipoprotein A.

CONCLUSIONS

South Asians with an elevated lipoprotein A have an increased risk of coronary artery disease so they should have early enactment of lifestyle modification and aggressive medical management.

Apheresis as novel treatment for refractory angina with raised lipoprotein(a): a randomized controlled cross-over trial

Aims

To determine the clinical impact of lipoprotein apheresis in patients with refractory angina and raised lipoprotein(a) > 500 mg/L on the primary end point of quantitative myocardial perfusion, as well as secondary end points including atheroma burden, exercise capacity, symptoms, and quality of life.

Methods

We conducted a single-blinded randomized controlled trial in 20 patients with refractory angina and raised lipoprotein(a) > 500 mg/L, with 3 months of blinded weekly lipoprotein apheresis or sham, followed by crossover. The primary endpoint was change in quantitative myocardial perfusion reserve (MPR) assessed by cardiovascular magnetic resonance. Secondary endpoints included measures of atheroma burden, exercise capacity, symptoms and quality of life.

Results

The primary endpoint, namely MPR, increased following apheresis (0.47; 95% CI 0.31-0.63) compared with sham (-0.16; 95% CI - 0.33-0.02) yielding a net treatment increase of 0.63 (95% CI 0.37-0.89; P < 0.001 between groups). Improvements with apheresis compared with sham also occurred in atherosclerotic burden as assessed by total carotid wall volume (P < 0.001), exercise capacity by the 6 min walk test (P = 0.001), 4 of 5 domains of the Seattle angina questionnaire (all P < 0.02) and quality of life physical component summary by the short form 36 survey (P = 0.001).

Conclusion

Lipoprotein apheresis may represent an effective novel treatment for patients with refractory angina and raised lipoprotein(a) improving myocardial perfusion, atheroma burden, exercise capacity and symptoms.

Specific Lp(a) apheresis: A tool to prove lipoprotein(a) atherogenicity

BACKGROUND

An elevated lipoprotein(a) (Lp(a)) level is observed in more than 30% of patients with stable ischemic heart disease (SIHD). We conducted an investigation of the effects of specific Lp(a) apheresis on the progression of atherosclerosis in SIHD patients with Lp(a) levels greater than 50 mg/dL.

METHODS

We prospectively enrolled 15 patients diagnosed with SIHD based on symptom-driven coronary angiography findings, with Lp(a) ≥50 mg/dL and a low density lipoprotein cholesterol (LDL-C) ≤2.5 mmol/L, who were on long-term statin therapy. They underwent weekly Lp(a) apheresis using Lp(a) Lipopak^® adsorption columns which contain monospecific sheep polyclonal antibodies against human Lp(a). Fifteen age and gender matched SIHD patients receiving atorvastatin monotherapy served as controls. At baseline and 18 months post-treatment, quantitative coronary angiography, intracoronary ultrasound with virtual histology and carotid ultrasound were performed. Lipid profile, including Lp(a), was measured at the scheduled visits, and before and after each apheresis procedure. Levels of high-sensitivity C-reactive protein (hsCRP), matrix metalloproteinases (MMP)-7 and 9, and tissue inhibitor of matrix metalloproteinases (TIMP)-1 and 2 were determined at baseline and at the end of the study period.

RESULTS

Each specific Lp(a) apheresis procedure was carried out with two adsorption columns resulting in an average acute decrease in Lp(a) levels of 75% (from 110 ± 22 to 29 ± 16 mg/dL) without significant changes in other plasma components. Lp(a) reduction over the course of 18 months was associated with a decrease in the mean percent diameter stenosis of 5.05% and an increase in minimal lumen diameter of 14%; the mean total atheroma volume was reduced by 4.60 mm³ (p < 0.05 for all). There was a decrease in absolute common carotid intima-media thickness in the Lp(a) apheresis group of 0.07 ± 0.15 mm both from baseline and compared with the control group (p = 0.01). Levels of hsCRP were reduced by 40% in patients on Lp(a) apheresis without significant changes in the levels of other biomarkers at the end of the study.

CONCLUSION

Reduction of the atherosclerotic burden in coronary and carotid arteries was observed in patients treated with specific Lp(a) apheresis and statin over 18 months compared with statin therapy alone. These findings support the atherogenic role of Lp(a) and reinforce the need to assess the effects of Lp(a)-lowering on cardiovascular events and mortality. Trial Registration Clinicaltrials.gov (NCT02133807).

Lipoprotein(a) apheresis

PURPOSE OF REVIEW

Currently, different methods for extracorporeal elimination of atherogenic apolipoprotein B100 containing lipoprotein particles are used in clinical practice. Most of them effectively remove both lipoprotein(a) [Lp(a)] and LDL. The aim of this review is to highlight research describing the clinical advantages of specific Lp(a) immunosorption compared with other lipoprotein apheresis systems.

RECENT FINDINGS

Data on the utility of lipoprotein apheresis in patients with elevated Lp(a) level are limited. However, several longitudinal studies demonstrated improvement in cardiovascular outcomes when both Lp(a) and LDL cholesterol levels were decreased with different apheresis systems. The main limitation of these trials is the absence of a control group. First developed in 1991, studies on apheresis with a specific immunosorbent to Lp(a) were small and noncontrolled before 2000s. The only prospective controlled clinical trial utilising Lp(a) apheresis (Clinicaltrials.gov NCT02133807), demonstrated regression of coronary and carotid atherosclerosis when Lp(a) was removed weekly for 18 months.

SUMMARY

Lipoprotein apheresis usually affects multiple lipoproteins, and there are minimal data regarding the effect of specific removal of Lp(a) alone. There is a need for randomized controlled trial with specific Lp(a) apheresis to investigate its effect on cardiovascular outcomes.

High prevalence of raised lipoprotein(a) in patients with refractory angina

Background: Angina that is refractory to conventional medical therapy and revascularisation, remains challenging to manage and poses significant burden to patients. Elevated lipoprotein(a) [Lp(a)] has emerged as an important independent cardiovascular risk factor and predictor of adverse outcomes in atherosclerotic disease. The prevalence of raised Lp(a) amongst patients with refractory angina has not yet been defined. Objective: To establish the prevalence of raised [Lp(a)] >500 mg/L in patients with refractory angina. Methods: We conducted an epidemiological screening pilot study in 75 patients with refractory angina from a UK tertiary cardiac centre. We determined the proportion of the cohort with raised Lp(a) >500 mg/L using an isoform-insensitive method. In addition, a full fasting lipid profile (including: LDL cholesterol, HDL cholesterol, total cholesterol to HDL ratio and triglycerides) was obtained. Patients were also asked about the presence of conventional cardiovascular risk factors. Results: Our study demonstrated that 60% of the 75 patients with refractory angina had raised Lp(a) levels of >500 mg/L. The median and inter-quartile range of Lp(a) values were 771 mg/L (162 mg/L,1260 mg/L) respectively. Conclusions: This high prevalence of raised Lp(a) detected in our cohort with refractory angina may suggest a causal role. Further research is necessary to confirm this association and prospective studies are needed to explore the potential therapeutic benefit of Lp(a) reduction in patients with refractory angina.

The expanding role of lipoprotein apheresis in the treatment of raised lipoprotein(a) in ischaemic heart disease and refractory angina

It is increasingly recognised that lipoprotein(a) [Lp(a)], an inherited, genetically-determined form of LDL-cholesterol, is an independent cardiovascular risk factor and predictor of adverse cardiovascular outcomes. Lp(a) is felt to increase cardiovascular risk via its pro-thrombotic effect and by enhancing intimal lipoprotein deposition. Lipoprotein apheresis is currently the most effective treatment for raised Lp(a). There is a growing body of evidence suggesting that aggressively lowering raised Lp(a) may improve cardiovascular and clinical outcomes, although much more research is required in this field.

Angina which is refractory to conventional medical therapy and revascularisation, is extremely challenging to manage. Treatment options for such patients remain very limited. We describe the case of a patient with refractory angina and raised lipoprotein(a) in whom aggressive reduction of Lp(a) with lipoprotein apheresis successfully ameliorated the progression of coronary stenosis and provided effective and durable relief of angina symptoms. In our centre, we are currently conducting a prospective, randomised controlled cross-over study of patients with refractory angina and raised Lp(a), randomised to undergoing lipoprotein apheresis or ‘sham’ apheresis with assessment of myocardial perfusion, carotid atherosclerosis, endothelial vascular function, thrombogenesis, oxidised phospholipids and their antibodies, exercise capacity, angina symptoms and quality of life at the beginning and end of treatment.

Treatment of symptomatic HyperLp(a)lipoproteinemia with LDL-apheresis: a multicentre study

LDL-apheresis (LDLa) efficacy in the treatment of symptomatic HyperLp(a)lipoproteinemia -HyperLp(a)- has been studied in a multicentre trial. After 3.1+/-2.7 years of weekly and biweekly treatment, the data from 19 patients (males:12; females:7; aged 53.8+/-9.3 years; mean body mass index: 24.6+/-2.3 Kg/m²) were evaluated. Data were collected using the same questionnaire shared by 5 participating centres. A total of 2331 procedures were performed. A mean of 3593.7+/-800.3 ml of plasma or 8115.3+/-2150.1 ml of blood, depending upon the technique used (H.E.L.P., D.A.LI., Dextransulphate, Lipocollect 200), was regularly treated on average every 10.1+/-2.6 days. Baseline mean Lp(a) levels were 172.3+/-153.8 mg/dL. The mean pre-/post-apheresis Lp(a) levels decreased from 124.5+/-107.2 mg/dL (p<0.001 vs baseline) to 34.2+/-40.6 mg/dL (p<0.001 vs pre-). Baseline mean LDL-cholesterol (LDLC) levels were 152.3+/-74.6 mg/dL. The mean pre-/post-apheresis LDLC levels decreased from 130.4+/-61.1 mg/dL (p<0.004 vs baseline) to 41.2+/-25.1 mg/dL (p<0.001 vs pre-). The hypolipidemic drugs given to the patients during LDLa were: ezetimibe+simvastatin, atorvastatin, rosuvastatin, pravastatin, acipimox, and omega-3 fatty acids. 58% of the patients had arterial hypertension. Cigarette smokers were 5.3%. Alcohol intake was present in 21%. 52.6% were physically active. Patients with coronary artery disease (CAD) submitted to coronary catheterization before LDLa were 95%. In 5.5% (#1) CAD recurred despite treatment with LDLa. 79% were submitted to coronary revascularization before LDLa. CAD was: monovasal in 8 patients (42.1%), bivasal in 5 (26.4%), trivasal in 4 (21%), plurivasal in 2 (10.5%). In 94.5% of the sample the lesions were stable (< 0% deviation) over 3.1+/-2.7 years. 37% had both CAD and extra-coronary artery disease. This multicentre study confirmed that long-term treatment with LDLa was at least able to stabilize CAD in the majority of the individuals with symptomatic HyperLp(a).