1. Going beyond the routine !
Is measuring apo B and Lp (a) of
value ?
Dr Akshay Mehta
Dr B Nanavati Hospital
Asian Heart Institute

2. Why go beyond the routine
(lipid profile) ?
• Acute coronary syndromes in up to one-half of patients with
“normal” cholesterol levels
• Approximately 34% of adults in the United States have the
metabolic syndrome with characteristically high TG, low HDL-
C, and LDL-C often within normal limits
• 30% relative risk reduction with statin therapy -significant
CHD still with LDL-C at goal ---“residual risk”
Increase in MetS has caused increased FFA load on liver and down regulation
of LPL due to relative Insulin inefficiency.

3. To go beyond the routine, we have to
understand……..
• A paradigm of numbers
• The enigma of Lp(a)

4. Particle number v/s Lipid level
A paradigm to understand
• Cholesterol is carried into the arterial wall within a LP particle
and …
• the number of LP particles determines the likelihood of
cholesterol entering and lodging within an arterial wall
• Now, the lipid composition of the principal atherogenic
lipoproteins differs substantially amongst individuals
because the number of particles within any lipoprotein fraction determines the likelihood
of any member of that class entering and lodging within an arterial wall

5. For example the amount of cholesterol carried by an
LDL particle varies greatly between individuals and
can also change in response to lipid altering Rx.
Apo B versus cholesterol in estimating cardiovascular risk and in guiding
therapy: report of the thirty‐person/ten‐country panel
Report of the thirty person/ten country panel
Journal of Internal Medicine, 10 FEB 2006

6. • Thus, for the same amount of cholesterol measured in 2
individuals, their LP particle number may be different
• Therefore, lipid levels do not automatically match lipoprotein
particle levels.
• And the risk due to a lipid fraction not same as the risk due to
the LP fraction
• Hence, the total number of atherogenic particles is a more
important determinant of the risk of vascular disease than the
level of any of the conventional lipids (TC, TG etc)

7. So how does one measure the particle
number ?
1. NMR spectroscopy
2. By measuring apoB

8. Why apo B ?
• each VLDL, IDL, LDL, and Lp(a) lipoprotein particle contains
one molecule of apo B100
• Each chylomicron and chylomicron remnant particle contains
one molecule of apo B48.
• Clinical assays of apoB measure both apo B100 and apo B48.
• Hence total plasma apo B = (apo B100 +apo B48) represents
the total atherogenic particle number

9. Is apo B better than LDL-C ?
• Insulin resistance and type 2 diabetes mellitus, MetS, CKD
• Familial combined hyperlipidaemia, (associated with premature
coronary artery disease)
• The Quebec Cardiovascular Study, the AMORIS study, the
Thrombo Study , the Thrombo Metabolic Syndrome Study, the
Northwick Park Heart Study, the Nurses’ Health Study and patients
with type 2 diabetes in the Health Professionals’ Follow-up Study
• INTERHEART Study – 52 countries, 30,000 people – value of apo
B/A1 ratio (accounted for over 50% of CV events)
• Hence apo B has entered ESC guidelines for risk estimation and
target of Rx

10. Lipid profile in control population
in INTREHEART by ethnicity (Men)
N=14,637 South Asian Chinese European Black African
TC (mg/dl) 184 182 203 158
HDL (mg/dl) 32 41 43 41
TC/ HDL 5.71 4.47 4.71 3.85
Non- HDL-C 148 139 156 114
Apo B (mg/dl) 88 79 93 70
Apo A1( mg/dl) 105 119 122 110
Apo B/Apo A1 0.84 0.66 0.76 0.64

11. What happens on statin Rx ?
• LDL cholesterol reduced more than apo B
• Thus apo B on statin therapy will be relatively higher than LDL
cholesterol
• Thus on treatment apo B should be a more reliable index of
the residual risk
• In 4S, LIPID, AFCAPS/TexCAPS, the Leiden Heart Study and the
Thrombo Study on-treatment apo B was more predictive of
the residual risk of vascular events

12. Thus, advantages of measuring apo B:
• apo B-guided statin therapy should be substantially more
effective than Rx guided by LDL cholesterol
• Enables focus on one rather than several variables
• Non fasting sample
• Measurement standardized by IFCC/WHO
• Indirect measurement of LDL-C requires fasting sample and
direct measurement of LDL-C not standardized.

13. But problems with apo B testing
• Test costs ($79.15 v/s $59.20 for an entire conventional lipid
panel)
• Significant lag time in test result reporting
• Poor goal attainment rates on standard therapies, including
high-dose statins, with limited evidence for other available
interventions and therapeutic effects.
• Discrepant cut off values…….
Drug therapies known to alter advanced lipoprotein analysis parameters, specifically
niacin and fenofibrate, have not been shown to additionally reduce cardiovascular risk
in recent randomized trials of high-risk patients treated with statin therapy.

14. Discrepant apo B cutoffs
• The American Diabetes Association (ADA)/American College of Cardiology
(ACC) position statement recommends an apoB goal of <80 mg/dl in
highest-risk patients and <90 mg/dl in high-risk patients.
• In contrast, the American Association of Clinical Chemistry (AACC)
recommends an apoB goal of <80 mg/dl in high-risk patients and
<100mg/dl in moderate risk people.
• The Canadian Cardiovascular Society is in disagreement with the ADA/ACC
and the AACC, as they recommend an apoB <80 mg/dl as the primary
therapeutic target in high- and moderate-risk patients

15. Can non HDL-C be a surrogate for
apo B ?

16. HDL-C and apo B : similar, but different !

17. • Thus, although of apparently similar significance,
measurement of the number of atherogenic particles may be
more biologically meaningful than the measurement of the
cholesterol content in these particles because :
• Cholesterol is carried into the arterial wall within a LP particle
and …
• the number of LP particles determines the likelihood of
cholesterol entering and lodging within an arterial wall

18. Advantages of non HDL-C
• Established cutpoints which remain valid and independent of
increasingly discrepant population percentiles
• No additional cost
• Quick calculation of TC minus HDL-C (Freedom from LDLC,TG !)
• Well-documented intervention effects
• Existence within our current “cholesterol-oriented” conceptual
framework
• Non fasting sample

19. Is non HDL-C better than LDL-C ?
• The Lipid Research Clinics Program Follow-Up study- Pr Prev of
4,462 non–HDL-C > LDL-C as predictor of all-cause & CVD mortality
• The BARI sec prev of 1,514 – 5 yrs follow up : non HDL-C
a better predictor of non fatal MI
• In Hypertriglyceridemic States : a pooled post-hoc analysis of
outcomes using data from Framingham Cohort Study, Framingham
Offspring Study, Lipid Research Clinics Prevalence Follow-Up study,
and the MRFIT — significantly higher values of non–HDL-C in
diabetic patients compared with nondiabetic patients but nearly
identical LDL-C levels

21. Even independent of TG levels :
• In the SHEP 4,736 primary and secondary prevention pts non
HDL-C an independent predictor of CHD regardless of TG
levels
• EPIC-Norfolk study non–HDL-C strongest predictor of future
CHD across all other lipid-stratified levels, including patients
with a TG <200 mg/dl.
• The ERFC (Emerging Risk Factors Collaboration) found that TG
levels were not independently associated with CHD risk once
adjusted for non–HDL-C in 302,430 individuals

22. Hence both apoB and non–HDL-C are valuable
for CVD risk prediction with benefits beyond
that of LDL-C

23. Apo B v/s non HDL-C:
The Great Fight !

24. Apo B better than non HDLC
• The Health Professionals Follow-Up study (2005 Circulation)
• AMORIS study 2004 (apoB/A1 ratio,Lancet 2001)
• Framingham Offspring Study (J Clin Lipidol. 2007)

25.  non HDL-C as good….
• Women's Heart Study
• Emerging Risk Factors Collaboration
 ……..or better than apo B
• Postmortem examination from the PDAY (Pathological
Determinants of Atherosclerosis in Youth) study
• Combined analysis of TNT and IDEAL

26. Comparison of Apo B and Non-HDL- C for
Identifying CAD Risk Based on Receiver
Operating Curve Analysis
Stanley S. Levinson, PhD, DABCC
Am J Clin Pathol. 2007;127(3):449-455.
• The ability of apo B to discriminate between disease and
nondisease was compared with non-HDLC and other
lipoprotein lipids in 437 men who had undergone coronary
angiography
• When results were evaluated by multivariate techniques and
expressed as odd ratios there was significant difference b/w
the 2 as risk predictors
• But when analysed by receiver operating characteristic (ROC)
curves, and adjusted with other RF, the difference between
apo B and lipid factors proved to be insignificant.

27. Lipid-Related Markers and
Cardiovascular Disease Prediction
The Emerging Risk Factors Collaboration*
JAMA. 2012;307(23):2499-2506
 Objective
 To determine whether replacing or adding information on apo
B and apo A-I, lp(a), or lp-associated phospholipase A2 to
 Total C and HDL C improves cardiovascular disease (CVD) risk
prediction.

28. Results
 use of any of the apolipoproteins instead of current
markers gave a worse prediction
 use of any of them on top of current markers
improved risk prediction but only very slightly (C
statistic)

29. So should we measure apoB
in routine practice ?
• Findings of better performance of apo B compared
with non–HDL-C are controversial-
• The difference b/w the two vanish when corrected
for characteristics of insulin resistance
• Although residual risk is 30% on std doses of statins,
it is about 45% on intensive statin therapy

30. Also…
• Doing apo B etc would not address the residual risk of other
well-established cardiovascular risk factors, such as aging,
male sex, hypertension, or smoking
• No superiority of treatment strategies incorporating non
statin lipid-modifying agents compared with intensive statin
therapy –SANDS, ACCORD, AIM-HIGH, HPS THRIVE II
• Hence both apoB and non–HDL-C are valuable parameters
available to physicians for CVD risk prediction and
stratification, with benefits beyond that of LDL-C
• But non HDL-C is a more realistic target of therapy with
intensive statin therapy until it can be shown by prospective
studies that there is some definitive advantage on an absolute
basis for using apo B.

31. NHDL cholesterol and CVD risk
• Non HDL-C calculation
 Non-HDL-C = TC-HDL-C
• Non- HDL-C goal
 30 mg/dL above goal for LDL-C
• Significance of non-HDL-C
 Encompasses all known and potential atherogenic lipid
particles (linearly proportional to Apo B)
 Has been shown to be a stronger predictor of cardiovascular
death than LDL-C, especially in women

32. Risk category LDL-C (mg/dL) Non-HDL-C
CHD and CHD Risk < 100 <130
equivalent
(10 year CHD death risk>
20%)
Multiple (>= 2) risk <130 <160
factors
(10 years CHD death risk
<20%)
0-1 risk factor < 160 <190

33. What about Lp(a) ?
• Lp(a) is a plasma protein composed of an LDL particle linked
to apo(a), which has structural homology with plasminogen.
• Lp(a) may therefore contribute to both intimal cholesterol
deposition and prothrombotic potential
• Genetically determined Lp(a) levels are continuously and
linearly related to risk of CVD independent of lifestyle, lipid
levels.
• Thus , both a risk factor and a risk marker esp of premature
CHD.
• Highly consistent levels within individuals across many years
since birth thus effect of Lp(a) on CHD risk can be assessed
using a single measurement

34.  Asian Indians have Lp(a) levels intermediate between whites
and blacks (less dangerous large isoforms and high HDL levels)
 The combination of high Lp(a) and low HDL is found in 42% of
Indians

35. Problems with Lp(a)
• Measurement of Lp(a) levels is done by a variety of methods and
is not fully standardized, and is performed with several assays.
• Ideally, assays should be reported as nmol/l using a WHO–
approved, IFCC and Laboratory Medicine reference standard
apo(a) This assay measures Lp(a) as moles of apo(a) protein
using specific monoclonal antibodies, is independent of isoform
size.
• Lp(a) can also be measured as mg/dl representing the entire
mass of Lp(a) (protein, lipid, and carbohydrate). These assays
must be validated with reference standards.
• Lp(a) can also be measured as Lp(a) “cholesterol” in mg/dl and
assayed using quantification gradient analysis, but the published
database for the predictive value of this assay is significantly
smaller than the others.

36. Problems with Lp(a)
• Reference ranges vary and depend on assay and reporting
laboratories.
• They also differ by population and may differ regionally
worldwide
• Reference ranges for individual race/ethnicities yet to be
developed
• Specifically targeted therapies to lower Lp(a) are not
available.

37. Available Rx for high Lp(a)
 Niacin and estrogens lower Lp(a) up to 30%
 Aspirin
 Statins either have no effect or increase Lp(a) levels
• Thyromimetics
• Cholesterol-ester-transfer protein (CETP inhibitors)
• Anti-sense oligonucleopeptides to apoB -Mipomersen
• Proprotein convertase subtilisin/kexin type 9 (PCSK-9) inhibitors.
• L-carnitine (2 g/day) may also reduce lipoprotein a levels
• Gingko biloba may be beneficial, but has not been clinically verified
• Coenzyme Q-10 and pine bark extract have been suggested as beneficial,
but neither has been proven in clinical trials

38. When to check for Lp(a) ?
• premature cardiovascular disease esp not explained by routine lipid
parameters or RF
• family history of premature cardiovascular disease
• family history of elevated lipoprotein (a)
• existing heart or vascular disease, especially with normal or only mildly
elevated lipids.
• recurrent cardiovascular disease despite statin treatment
• familial hypercholesterolaemia, especially low HDL-C
• Patients with a moderate or high risk of cardiovascular disease (2010
European Atherosclerosis Society Consensus Panel)

39. Lp(a) Cut points
1. Desirable: < 14 mg/dL (< 35 nmol/l)
2. Borderline risk: 14 - 30 mg/dL (35 - 75 nmol/l)
3. High risk: 31 - 50 mg/dL (75 - 125 nmol/l)
4. Very high risk: > 50 mg/dL (> 125 nmol/l)
5. If the level is elevated, treatment should be initiated with
a goal of bringing the level below 50 mg/dL
6. most studies and meta-analyses show an increase in CVD
risk starting at Lp(a) >25 mg/dl

41. CONCLUSIONS :
1. Non HDL-C a practical and realistic target of therapy beyond
LDL-C
2. No need for apo-B measurement in ROUTINE practice
3. Continue using intensive statin therapy
4. No sound evidence yet of additional non statin therapy
5. Measure Lp(a) in special situations
6. Await specifically targeted Rx for Lp(a)

42. THANK YOU!!