Lipoprotein (a) Disclosures 2/20/2013. Lipoprotein (a): Should We Measure? Should We Treat? Health Diagnostic Laboratory, Inc. No other disclosures

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1 Lipoprotein (a): Should We Measure? Should We Treat? Joseph P. McConnell, Ph.D. DABCC Health Diagnostic Laboratory Inc. Baptist Health South Florida Eleventh Annual Cardiovascular Disease Prevention International Symposium Miami Beach Florida February 17, 2012 Disclosures Health Diagnostic Laboratory, Inc. Chief Laboratory Officer and Co-Founder No other disclosures Lipoprotein (a) Should we Measure? Should we Treat? Yes! Yes! The real Question to both is How??? 1

2 Lipoprotein (a) Discovered by Kare Berg: 1963 Particle structure containing a single copy of apolipoproteinb covalently linked to a protein of variable mass not found in other lipoproteins He called the new particle lipoprotein (a) Studies noted its association with vascular disease (coronary, cerebral and peripheral) Lipoprotein (a) I would propose to you that Lp(a) is the most atherogenic lipoprotein in the human body. Lp(a) is the Rodney Dangerfield of Lipoproteins It doesn t get any respect! Lipoprotein (a) Structure Apo (a) 5 Kringle Active site (Protease) Size heterogeneity (~ KDa) Lipoprotein (a) Apo-B Why is Lp(a) atherogenic? Plasminogen 2

3 Why is Lp(a) Atherogenic? Quadruple Whammy! Has all the properties of LDL. Has structural homology with plasminogenand inhibits fibrinolysis. May serve as a sink for oxidized pholpholipids. Tsimikas, et al. NEJM, Inhibits tissue factor pathway inhibitor(tfpi) activity. Promotes thrombosis Manuscript in Preparation Elevated Lipoprotein(a) is associated with decreased plasma TFPI activity in human subjects. Promotes thrombosis Tissue Factor Pathway Inhibitor (TFPI), previously known as Lipoprotein Associated Coagulation Inhibitor (LACI) Submitted to Journal of Thrombosis and Haemostasis 3

4 Lp(a) Concentration in the Cardiac Rehabilitation Unit We measured Lp(a) in 71 patients from 2 cardiac rehabilitation units 1/71 had elevated Lp(a): 58% In a population of 357 employees 126/357 had elevated Lp(a): 35% Clinical Significance of Lp(a) Is Lp(a) Atherogenic? Numerous retrospective case control studies Virtually all show strong link between Lp(a) and vascular disease Prospective studies with Discordant results Several studies: conclude Lp(a) is an independent risk factor Some studies reach the opposite conclusion Relative Risks of Future MI Among Apparently Healthy Middle-Aged Men Lipoprotein (a) Homocysteine Total Cholesterol Fibrinogen T-PA antigen TC/HDL CRP hscrp + TC/HDL Physicians Health Study Ridker: Ann Intern Med 130:933, 1999

5 Danesh J, et al.,circulation. 2000;102(10): Lp(a) and CHD Reykjavik Study (n=18 569) 207 patients with first-ever MI or who died of CHD. vs control participants in the Arch Int. Med. 2008;168(6): Lp(a) is Causal Risk Factor for MI Copenhagen Heart Study Examined genetic data and Lp(a) levels 5,098 patients, 282 MI events over -16 years Employed mendelian randomization approach to link Lp(a) genotype to Lp(a) level, and to MI Consistent with a causal association of elevated Lp(a) levels with increased MI risk. Kamstrup etal., JAMA, June 10, (22),

Lp(a) Proven as Causal Factor for MI Copenhagen Heart Study European Atherosclerosis Society Recommends Screening for Lp(a) Patients at moderate or high risk for CVD should be screened for Lp(a).

6 Lp(a) Proven as Causal Factor for MI Copenhagen Heart Study European Atherosclerosis Society Recommends Screening for Lp(a) Patients at moderate or high risk for CVD should be screened for Lp(a). Bringing a Patients Lp(a) < 50 mg/dlshould be a treatment priority. 1-3 g niacin is best treatment for Lp(a) but further studies are needed to better define treatment and target level. June 2010 Press Release: European Atherosclerosis Society Consensus panel Nordestgaard BG, et al., Eur Heart J Dec;31(23):28-53 Is there evidence that individuals identified by the biomarker of interest will benefit from an intervention or therapy they otherwise would not have received? For hscrp, the answer is a solid yes, and for Lp(a), a solid no. Lp(a) doesn t get any respect 6

7 Clinical Significance of Lp(a) Why the discordant results? Analytical techniques not standardized Size heterogeneity of apo(a) Different populations have different distributions skewed distribution in Whites and Asians more normal distribution in blacks Lp(a) in Blacks: nearly 2X values in Whites Lp(a) Analytical Standardization Lp(a) (mg/dl): Method y = x R = 0.566, N = Lp (a) (mg/dl): Method 1 7

Effect of KringleNumber on Lp(a) Analysis MarcovinaSM et al, Clinical Chemistry: 2000 To various degrees, apo(a) size heterogeneity affects the outcome of the immunochemical methods used to

8 Effect of KringleNumber on Lp(a) Analysis MarcovinaSM et al, Clinical Chemistry: 2000 To various degrees, apo(a) size heterogeneity affects the outcome of the immunochemical methods used to measure Lp(a). The major problem in the lack of accuracy is the over-or underestimation of Lp(a) values as a result of apo(a) size heterogeniety. Apo(a) Isoformsize and Coronary Artery Disease 8

Apo (a) Isoform Size Effect Large isoforms: Likely not as atherogenic as small isoforms Produce increased signals on immunoassay False positive Small isoforms Likely the more atherogenic form Produce

9 Apo (a) Isoform Size Effect Large isoforms: Likely not as atherogenic as small isoforms Produce increased signals on immunoassay False positive Small isoforms Likely the more atherogenic form Produce decreased signals on immunoassay False negative Is There An Isoform Independent Method? Immunologic methods All commercially available immunologic methods exhibit some isoform bias Lp(a) cholesterol determination Measure the cholesterol content of Lp(a) just like HDL or LDL cholesterol are measured. 9

10 Lp (a) Cholesterol Measurement Electrophoresis and enzymatic cholesterol staining LDL VLDL Lp (a) HDL Lp (a) cholesterol measurement is not influenced by apo (a) size Novel Risk Markers Relation to Angiographic CAD and Events 50 consecutive patients undergoing coronary angiography Vessel Disease 2V 3V 1V None Mild Mean Age 60 ± 11 years, 62% Male 6% patients have none or mild coronary occlusion 5% patients have significant occlusion (>50% stenosis) HR For Angiographic CAD Multivariate Variable HR 95% CI P-Value Age < Male Gender < Hypertension Smoking Total cholesterol HDL cholesterol Log triglyceride Log CRP Fibrinogen Lp-PLA Lp(a) mass (per 20 mg/dl) Lp(a) chol(per 5 mg/dl) McConnell et al, Circulation 2007 Oct; 116(16 Suppl S):

2/20/2013 HR For CVD Events in 25 non-ami Multivariate Variable Age Male Gender Hypertension Smoking LDL cholesterol HDL cholesterol Log triglyceride Log CRP Fibrinogen Lp-PLA2 Lp(a) protein: > 30

11 2/20/2013 HR For CVD Events in 25 non-ami Multivariate Variable Age Male Gender Hypertension Smoking LDL cholesterol HDL cholesterol Log triglyceride Log CRP Fibrinogen Lp-PLA2 Lp(a) protein: > 30 mg/dl Lp(a) cholesterol: >3 mg/dl HR % CI McConnell et al, Circulation 2007 Oct; 116(16 Suppl S):818. Lipoprotein (a): Relation to Angiographic CAD and Events Lp(a) cholesterol measurement is not influenced by apo (a) isoform size. Lp(a) cholesterol is a better predictor of angiographic CAD and events than immunologic Lp(a) mass measurement Discordance Between Lp(a)-C and Lp(a) Mass When Kringles Vary Lp(a)-C = 3 mg/dl Lp(a)-C = 12 mg/dl mg/dl High signal mg/dl Lp(a) Mass Balance Low signal 11

Apo(a) mass is the amount of apoprotein (a) in a dl of plasma Lp(a)-C is the cholesterol trafficked within all of the Lp(a)

12 Discordance Between Lp(a)-C and Lp(a) Mass When Kringles Vary Lp (a) Cholesterol Measurement Electrophoresis and enzymatic cholesterol staining LDL VLDL Lp (a) HDL Lp (a) cholesterol measurement is not influenced by apo (a) size Lp(a) Measurements Apo(a) mass is the amount of apoprotein (a) in a dl of plasma Lp(a)-C is the cholesterol trafficked within all of the Lp(a) particles per dl Lp(a)-P is the # of LDL particles carrying apo(a) that exist in a dl of plasma Apo(a) mass Lp(a)-P Lp(a) (a)-c 12

13 Electrophoresis Expert Guadagno Cholesterol Gel Lanes 11-17: + abnormal samples IDL LDL VLDL Lp(a) IDL HDL IDL VLDL LDL Lp(a) HDL Triglyceride Gel Lanes 11-17: + abnormal samples IDL LDL VLDL IDL HDL Lp(a) IDL VLDL LDL Lp(a) HDL 13

14 Apo-B Gel Lanes 11-17: + abnormal samples IDL LDL vldl IDL Lp(a) IDL vldl LDL Lp(a) Lipoprotein Particle Concentration Each apobcontaining Lipoprotein contains only one apob molecule We know the molecular weight of apob and the concentration of apob, so we can calculate the number of atherogenic lipoprotein particles. Lp(a)-P: HDL by electrophoresis vs. NW Lab by immunoassay R = 0.97 The fractions & concentrations identified as e-lp(a)-p are identical to those identified by NW Lab. Similar results with different methods confirms both methods. 1

15 NMR-LDL-P vs. Electrophoresis LDL-P R = Y = 1.323X -29 N = 197 Lp(a)-P by Electrophoresis Lp(a) cholesterol (mg/dl) Lp(a)-P concentration Electrophoresis (nmol/l) LDL-P concentration Electrophoresis (nmol/l) Lp(a)-P+ LDL-P concentration Electrophoresis (nmol/l) < < LDL-P Nuclear magnetic resonance (nmol/l) Lp(a) Particle Concentration We have recently developed an assay to measure Lp(a) Particle Concentration. The method is also capable of quantitating LDL, IDL, and VLDL particles Differences between this and other methods (NMR, etc.) must be carefully studied 15

16 Lp(a): Should We Treat? Effect Lp(a) Level No effect on Lp(a) Niacin 20-0% Aspirin Variable L-Carnitine 20% HRT 17 23% Mipomersin 30-0% LDL apheresis Statins Fibrates Ezetamibe Lifestyle changes Diet and exercise Raloxifene European Atherosclerosis Society Recommends Screening for Lp(a) Patients at moderate or high risk for CVD should be screened for Lp(a). Bringing a Patients Lp(a) < 50 mg/dlshould be a treatment priority. 1-3 g niacin is best treatment for Lp(a) but further studies are needed to better define treatment and target level. June 2010 Press Release: European Atherosclerosis Society Consensus panel Nordestgaard BG, et al., Eur Heart J Dec;31(23):

17 Lp(a) and Hormone Replacement Probability of CVD by Increasing Concentration of Lp(a) Therapy for Lp(a) Sound Approach: Treat other risk factors aggressively in pateints with Lp(a) elevation. There is no current approach that selectively lowers Lp(a). Antisense oligonucleotides; Lp(a) target RCT with specific Lp(a) lowering 17

18 Lipoprotein (a) Conclusions Should we Measure? Yes! But consider the method that is being used. Should we Treat? Yes! Aggressive treatment of other risk factors. Niacin or statin niacin combination Studies needed with agents that selectively lower Lp(a). Thank You! 18

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sad EFFECTIVE DATE: POLICY LAST UPDATED: Medical Coverage Policy Measurement of Small Low Density Lipoprotein Particles sad EFFECTIVE DATE: 02 16 2010 POLICY LAST UPDATED: 10 15 2013 OVERVIEW Lipoprotein-associated phospholipase A2 (Lp-PLA2),