cardiac biomarker of acs and heart failure

1. Dr RAMDHAN KUMAR
KAMAT
SR CARDIOLOGY IGIMS

2. Food and Drug Administration (FDA) first defined a
biomarker in 1992 as “a laboratory measure or
physical sign that is used in therapeutic trials as a
substitute for a clinically meaningful end point that is
a direct measure of how a patient feels, functions, or
survives and is expected to predict the effect of the
therapy.”

3. Biologic marker (biomarker): A characteristic that is objectively
measured and evaluated as an indicator of normal biologic processes,
pathogenic processes, or pharmacologic responses to a therapeutic
intervention.
Surrogate endpoint : A biomarker intended to substitute for a
clinical endpoint. A surrogate endpoint is expected to predict clinical
benefit (or harm) or lack of benefit (or harm) based on epidemiologic,
therapeutic, pathophysiologic, or other scientific evidence.
Clinical endpoint : A characteristic or variable that reflects how a
patient feels, functions, or survives.
Biomarker Definitions

4. CARDIAC BIOMARKERS
Cardiac biomarkers are protein/enzyme
molecules released into the blood stream from
damaged heart muscle.
These biomarkers have a characteristic rise
and fall pattern.

5. HISTORY OF CARDIAC BIOMARKERS
1954 - SGOT (AST)
1955 - LDH
1960 - CPK
1972 - CPK isoforms by Electrophoresis
1975 - CK - MB by immunoinhibition
1975 - Myoglobin
1985 - CK - MB Mass immunoassay
1989 - Troponin T
1992 - Troponin I /hSTn 2000

7. Types of Biochemical Markers
1- Cardiac Enzymes (isoenzymes):
Total CK
CK-MB activity
CK-MB mass
2- Cardiac proteins:
Myoglobin
Troponins

9. PATHOPHYSIOLOGY BASIS OF BIOMARKERS
Biomarkers of inflammation .
C-reactive protein/hsCRP, Homocysteine.
Myeloperoxidase (MPO)
Soluble fragment CD40 ligand (sCD40L)
Biomarkers of plaque instability/disruption.
Pregnancy-associated plasma protein A(PAPP-A)
Choline
Placental growth factor
MMP-9
Myeloperoxidase (MPO)

10. Biomarkers of myocardial ischemia .
Ischemia-modified albumin (IMA)
Free fatty acids unbound to albumin (FFAu)
Heart-type fatty acid binding protein (H-FABP)
(PRENECROSIS)
Myocardial necrosis
cTn ,hscTn
CK-MB,
myoglobin
Pump failure,myocardiac stress
Nt-PROBNP,GDF-15,ST-2,ET-1

12. Stefan Blankenberg, MD; Renate Schnabel, MD; Edith Lubos, MD, et al., Myeloperoxidase Early Indicator of Acute Coronary Syndrome and
Predictor of Future Cardiovascular Events 2005

13. The ACC/AHA and European Society of Cardiology
(ESC) guidelines recommend cTnI or cTnT as the
preferred first-line marker.
CK-MB (by mass assay) is an acceptable
alternative.
If the initial set of markers is negative, another
sample should be drawn 3 to 6 hours later; if a high-
sensitivity assay is used, a 1-hour algorithm can be
considered.

14. CARDIAC TROPONINS
 Troponin is a protein complex located on the thin filament of
striated muscles consisting of the three subunits namely
Troponin T (TnT), Troponin I (TnI) and Troponin C (TnC) each
having different structure and function.
 TnT and TnI are being used as the biochemical markers for the
diagnosis of myocardial injury.
 The troponins found in cardiac tissue (cTn) have a
different amino acid sequence that present in troponin of
skeletal muscles.
 This makes cTnT and cTnI more specific for the diagnosis of
myocardial injury.
 These cardiac troponins (cTns) appear in the blood as early as
3-4 hours of the acute episode and remain elevated for 4-14
days.

16. 16
Increased Troponins
 Troponin T and I are not detected in healthy individuals.
 Significant increase in Troponins reflects myocardial
necrosis.
 ACC/ESC has defined increase in Troponins as a
measurement above 99th percentile value of reference
group.
 To reduce false-positive outcomes, CV of <10% at decision
limit is recommended.

19.  The pattern of release of
troponin may be
monophasic or biphasic.
 This release kinetics is
related to the distribution of
these proteins within the
myocardial cell.
 About 94-97% of these
troponins is bound to
myofibril and only 2-3% of
cTnI and 6%-8% of cTnT is
free in the cytoplasm
 When the myocardial
damage occurs the cytosolic
troponins reach the blood
stream quickly resulting in a
rapid peak of serum
troponin observed during the
first few hours.

20. Studies have shown that cardiac troponins should
replace CKMB The reasons being :
 Troponins are highly cardiospecific especially the
TnI (100%).
 The prolonged elevation (4-14 days) make it a good
marker for patients admitted to the hospital after
several days of MI.
 cTns have greater sensitivity for minor degrees of
myocardial injury due to the cardiospecificity and their
very low concentration in serum of normal individuals.
 These are excellent prognostic indicator in
patients with unstable angina and is a very useful
parameter for stratifying risk in acute coronary
syndrome(ACS).
Rottbauer W, Greten T, Muller-Bard off M et al. Troponin T:A

21.  A single measurement of serum cTnT at the time
corresponding to the slow continuous release after AMI
(~72 hours after onset) can be used as a convenient
and cost effective non-invasive estimate of infarct size
whereas CKMB requires repetitive sampling.
 The early serial measurements of cTnI are a more
accurate predictor of early coronary artery
reperfusion after thrombolytic therapy as compared
to CKMB and myoglobin.

22. According to U.S. National Academy of Clinical
Biochemistry (NACB) and Joint European Society of
Cardiology and American College of Cardiology (ESC/
ACC) guidelines cTns are the most specific and
sensitive biochemical markers.

23. cTnT Versus cTnI
 Both cTnT and cTnI are almost equally good markers and
it is difficulty to say which is better because both have
some positive and negative points.
 cTnI is 100% cardiospecific and it is not elevated in
chronic renal disease, trauma and skeletal muscle
disease.
 The overall diagnostic specificity and efficiency of cTnI is
better than cTnT.

24. 24
TROPONIN T
1.Cardiac Troponin T (cTnT) is present in fetal skeletal muscle.
2. In healthy adult skeletal muscle cTnT is absent.
3. The gene of cTnT may be re-expressed in skeletal muscle
disease. (Clin Chem. 1999;45:2129-2135)
4. Biological half life and early serum increases of cTnT are
similar to that of cTnI.

25. cTnI:
100 % cardiac specific
With greater sensitivity for diagnosing minor damage
of MI.
Appears in blood within 4 hours after onset of
infarction
peak: around 24 hours
Disappears from blood after 7-10 days (stays longer).
 So, useful for diagnosis of delayed admission cases
Prognostic marker (relation between level in blood &
extent of cardiac damage)

26. 6-8% 2-3%

27. COMPARISON
NEJM 2002;Vol.346,No.26:2079-82
28

28.  The other advantage of cTnI may be its greater
specificity in patients of ESRD.
 However, the important advantage of cTnT is that due
to international patent restrictions there is only one
assay for its measurement, thus cTnT demonstrates a
high degree of precision at the low end of measurement
range and a relatively uniform cut-off concentration.
 In contrast, at least 18 different commercial assays for
cTnI are available leading to considerable variation in the
cut-off concentrations in the definition of a myocardial
infarction by cTnI values.
 Thus, a clinician should be aware of the cTnI cut-off
values specifically associated with the particular assay
used by the laboratory.

29.  The life-time of cTnT in blood (10- 14 days) is
some what more than that of cTnI (7-10 days).
 Although cardiac troponins are extremely specific
for myocardial necrosis, but they do not
discriminate between ischaemic and non-
ischaemic etiologies of myocardial injury.
 The recommended time course for collection of
blood samples for cTn is at hospital admission, 6
and 12 hours later but when it is used along with
an early marker like myoglobin (two-marker
strategy) then at hospital admission, 4, 8 and 12.

30. WASH-OUT PHENOMENON.
 Patients with ST-segment elevation myocardial
infarction who achieve an effective reperfusion have
a greater and earlier peak plasma concentration of
troponin, followed by a faster return to normal – the
so-called “wash-out phenomenon” – compared with
those patients having no significant reperfusion.
 In this event, two blood samples should be collected –
at the time of the patient's admission to hospital,
and 90 min later – and the enzyme plasma
concentrations compared.
 The ratio between the concentrations at these two
points can be used to discriminate between
successful and unsuccessful reperfusion. In general,
the greater the ratio (at least 5), the more likely it
is that reperfusion has occurred.

32. AFTER CABG
Increase more than 10 x 99 percentile URL during first
72 hrs
5

33. Tn IN ESRD
 The cardiac troponin especially cTnT pose diagnostic
challenges in patients of chronic renal failure.
 Frequent cTnT elevations (30 to 70% of end stage renal
disease (ESRD) patients compared with <5% in similar
patients of cTnI) are seen in patients of renal failure in the
absence of clinical suspicion of ACS .
 The putative mechanisms for chronic elevation of troponin
in chronic renal disease patients include:
 endothelial dysfunction,
 acute cardiac stretch,
 microinfarction and
 left ventricular hypertrophy.
 uremic toxicity

34.  Increasing evidence suggests that chronically elevated troponin
levels indicate a worse long-term prognosis for cardiovascular
outcomes in this patient population
False positives have been reported with use of troponin- T in
ESRD patients but not as much with troponin-I
 CK: plasma concentrations are elevated in 30-70% of dialysis
patients at baseline, likely secondary to
1.skeletal myopathy,
2. intramuscular injections and
3. reduced clearance.
 CK-MB: 30-50% of dialysis patients exhibit an elevation in the MB
fraction .
 Therefore, the most specific marker for suspected AMI in ESRD
patients is Troponin-I.

35. 36
TROPONIN ASSAYS
 TropT (Roche Diagnostics, Germany)
 Trop I (Siemens Healthcare Diagnostics)
 Troponin T
 99th percentile limits - 0.01 ng/mL
 assay ranges - 0.01-25 ng/Ml
 (Troponin I)
 99th percentile limits -0.04 ng/mL
 assay range -0.04-40 ng/mL
 Reference limits based on the 99th percentile for a
healthy population are 0.01 ng/mL (Troponin T) and
0.04 ng/mL (Troponin I)

36. hsTn
Experts recommend that the term high-sensitivity troponin
(hsTn) be reserved for assays that can detect cardiac
troponin in more than 50% of an apparently healthy
population.
As high-sensitivity troponin (hsTn) assays that can
detect ultralow concentrations of troponin.

37. HIGH-SENSITIVITY CARDIAC TROPONIN.
High-sensitivity assays deliver more precise
measurement of very low concentrations of
cardiaospecific troponin. Such assays have greater
sensitivity than previous-generation assays, but also
have diminished clinical specificity.

38. High-sensitivity assays likely detect troponin release much
earlier than older-generation assays. HsTn assays have
improved overall diagnostic accuracy and enabled earlier
detection of myocardial injury. Moreover, hsTn assays facilitate
the adoption of criteria for rapidly changing concentration of
troponin over periods as short as 1 to 3 hours that aid in
discriminating acute myocardial injury from chronically
elevated values caused by underlying structural heart disease
(e.g., left ventricular hypertrophy)

39. Fourth-generation cTn assays currently
used in the United States are less
sensitive than hsTn assays available in
some European countries. Thus, two
negative cTn assays at least 6 hours
apart are needed to exclude MI with these
less sensitive assays.

40. Newer hsTn assays (approved in the United
States in 2017), it is possible with a single
measurement at presentation of less than 5 ng/L
to classify “very low risk” for MI or cardiac death
in the next 30 days (negative predictive value
[NPV], 99.6%).

41. Absolute changes in hsTn greater than 9.2 ng/L
are even more predictive of acute MI than a
single measure or relative changes between two
measurements. Use of absolute changes in hsTn
allow for rapid protocols as brief as 1 hour to rule
in or rule out MI.

42. Rapid Rule-Out of AMI:
Serial hscTnT measurements at 0 and 2 hours
to evaluate those patients with possible AMI.
With hscTnT, the following most often can rule
out AMI:
Values less than or equal to the sex-specific
99th percentile that we advocate (10 ng/L for
women and 15 ng/L for men)

43. Ruling In AMI
A rising pattern with at least one value above the 99th
percentile URL in patients with evidence of acute ischemia is
necessary for the diagnosis of AMI. Individualization is
necessary in the elderly, women, and diabetic and
postoperative patients who may be pauci-symptomatic.
An absolute baseline cut-off value of hscTnT of 52 ng/L has
been advocated in the rapid algorithms for the diagnosis of
acute myocardial injury. This criterion is reasonable for
patients with chest pain, but it will be too low for patients
with chronic elevations, the elderly, and those who are
critically ill. Cut-off value of 100 ng/L as diagnostic for acute
myocardial injury in the absence of end-stage renal disease.

44. Change criteria have also been advocated to diagnose
acute myocardial injury. A change of 50% or more
predicated on the reference change interval (the
change in values that guarantees the change is not
due to variation alone) has been suggested when
baseline values are near the 99th percentile URL.
However, when the baseline value is elevated,
changes of only 20% are recommended to maintain
sensitivity.

46. DRAWBACK

47. CK-MB
If a cardiac-specific troponin assay is not available, CK-MB measured
with a mass assay is the best alternative. Cardiac muscle contains
both the MM and the MB isoenzyme of CK. Other tissues can contain
small quantities of CK-MB, including the small intestine, tongue,
diaphragm, uterus, and prostate. Strenuous exercise, particularly in
trained long-distance runners or professional athletes, can elevate
both total CK and CK-MB. Because CK-MB can be detected in the
blood of healthy persons, the cutoff value for abnormal elevation of
CK-MB is usually set a few units above the upper reference limit.

48. Creatine kinase (CK) is a cytosolic enzyme
CK is a dimer composed of two subunits B (brain type) and M (muscle
type), resulting in three isoenzyme:
CK-BB (CK1) : is of brain origin, found in blood only when BBB is
damaged.
CK-MB (CK2) : it is relatively specific for myocardial origin.
CK-MM (CK3) : it is found primarily in skeletal muscle.
CK-MB

49. Total CK (sum of CK-MM, CK-MB & CK-BB)
non specific to cardiac tissue (available in skeletal ms.)
CK-MB (CK-2) activity
More specific than total CK
BUT: less specific than troponin I (available in sk. Ms)
Appears in blood: within 4-6 hours of onset of attack
Peak: 12 - 24 hours
Returns to normal: within 2 - 3 days (no long stay in blood)
Advantages: - useful for early diagnosis of MI
- useful for diagnosis reinfarction
Disadvantages: not used for delayed admission (more than
2 days)
Not 100% specific (elevated in sk.ms damage)

50. •CK-MB mass
- appears one hour earlier than CK-MB activity (more sensitive)
- So, useful for diagnosis of early cases & reinfarction.
- BUT: not for diagnosis of delayed admission cases
& less specific than troponin I
•Relative index = CK-MB mass / Total CK X 100
more than 5 % is indicative for MI

51. 52
DRAWBACKS
• False positive (for MI) CK-MB elevation can be seen in:
– Significant skeletal muscle injury
– The MB fraction is determined to be expressed during the
process of muscle regeneration
– Cardiac injury for reason other than MI
• Defibrillation
• Blunt chest trauma
• Cocaine abuse
The search for cardiac specificity continues…

52. Small-size heme protein found in all tissues mainly assists in oxygen
transport
It is released from all damaged tissues
Its level rises more rapidly than cTn and CK-MB.
Released from damaged tissue within 1 Hr
Normal value: 17.4-105.7 ng/ml
Timing:
• Earliest Rise:
• Peak
• Return to normal:
1-4 hrs
6-9 hrs
12 hrs
Myoglobin

53. CONDITIONS FOR MYOGLOBIN
INCREASE :
Acute myocardial infarction
Skeletal muscle damage, muscular
dystrophy, inflammatory myopathies
Renal failure, severe uremia
Shock and trauma

54.  Clinical usefulness of myoglobin :
 If myoglobin concentration remains within the
reference range 8 hours after the onset of chest pain,
AMI can be ruled out essentially.
DRAWBACKS
 Due to poor specificity, myoglobin levels do not always
predict myocardial injury

55. 2
3
4
7
6
5
myoglobin
CK-MB
cTnT
cTnI
COMPARISON OF CTN, CK-MB , MB
1
0
0 4 8 12 16 20 24 28 32 36 40 44 48
Time after onset of AMI (hours)
Χupperlimitofreferenceinterval

56. Other Biomarkers
C-reactive protein (CRP) rises substantially in the setting
of STEMI as a result of the inflammatory response to
myocyte necrosis and is associated with the subsequent
risk for death or HF. Natriuretic peptides reflect the
hemodynamic impact of the MI and are associated with
prognosis. Although both natriuretic eptides and CRP
enhance risk assessment, no clear guidance is available
on how to direct specific therapeutic maneuvers in the
setting of STEMI based on these biomarkers.

57. Growth differentiation factor-15, ST2, fibroblast growth
factor-23, and galectin-3 are also biomarkers that may
putatively reflect myocardial ischemia or its consequences
and have been associated with CV outcomes in clinical
studies of patients with SIHD.
Other novel biomarkers of hemodynamic stress, such as
midregional pro-adrenomedullin (MR-proADM) and
midregional pro–atrial natriuretic peptide.

58. Biomarkers of inflammation, such as interleukin-6,
myeloperoxidase, growth factors, cytokines, and
metalloproteinases, remain under study as potential
biomarkers.

59. Genetic and Transcriptomic Biomarkers
It is now also possible to study multigene expression from
peripheral blood cells, so called transcriptomics. For example,
a peripheral blood gene expression score based on
expression values for 23 genes from peripheral blood cells has
been developed and validated to assess the risk for obstructive
CAD; a high negative predictive value (NPV) with a very low
rate of major adverse cardiac events (MACE) over a 1-year
period was demonstrated in patients with a low gene
expression SCORE

60. Multimarker approaches
(e.g., simultaneous assessment of cTn, hs-CRP, and
BNP) can further improve risk stratification of patients
with NSTE ACS. While lipid measurements are less
helpful for individual prognostication assessment of the
low-density lipoprotein cholesterol (LDL-C) and
triglycerides, along with glucose or hemoglobin (Hb) A1c
can identify uncontrolled risk factors that with proper
management, could reduce the risk of future CV events.

62. BIOMARKERS OF HEART FAILURE (HF)

64. Biomarkers Used in Assessing Patients with Heart Failure

65. Inflammatory Mediators and Markers of Oxidative Stress:
Toll-like receptor molecule: The increased into the circulation of
toll-like receptor molecules makes them potentially useful as
biomarkers that can be used to assess risk and to provide
important insights into the mechanisms involved in the
pathogenesis of HF.
Cytokines: The mediators that have proved most useful as
biomarkers in HF include the proinflammatory cytokines, tumor
necrosis factor-alpha, interleukin (IL)-1, IL-6, growth
differentiation factor 15 (GDF-15), and C-reactive protein (CRP).
Suppressor of tumorgenicity 2 (ST2) concentrations are elevated
in HF. Galectin-3 (gal-3), a β-galactoside–binding lectin member
of the galectin family, is another biomarker of inflammatory
response in HF.
BIOMARKERS FOR PREVENTION, ASSESSMENT, AND
MANAGEMENT OF HEART FAILURE

66. Myocyte Injury and Stress:
•Release of troponin T (TnT) and troponin I (TnI)
occurs in HF in the absence of an acute coronary
event.
•BNP and its amino terminal NT-BNP are released
into circulation directly from the myocardium as a
result of end-diastolic stress as results of
increases in volume or pressure.

67. Assessing Risk of Incident HF
BNP and NT-proBNP have the best predictive value. In
community-based populations, measurement of natriuretic
peptides (BNP or NT-proBNP) or markers of myocardial injury
(TnI or TnT) alone adds prognostic information to standard risk
factors for predicting new-onset HF.
Renal dysfunction as reflected by creatinine or cystatin-C is a
strong predictor of new-onset HF. Gal-3, sST2, and GDF-15
collectively have shown to have additive prognostic value in risk
models for new-onset HF. Therefore, measurement of several
new biomarkers, including sST2, Gal-3, GDF-15, and markers
of renal function, alone or in a multimarker strategy, may be
useful for providing additional risk stratification.

68. Biomarkers for Diagnosis of HF:
 BNP diagnoses HF in patients presenting to the emergency
department with shortness of breath, with a sensitivity of 90%
and specificity of 76% at a cut-off value of 100 pg/ml; the
proposed rule-in cutoff is >400 pg/ml. For NT-proBNP to
improve, positive predictive value age-related cut-offs of 450
pg/ml for <50 years, 900 pg/ml for 50-75 years, and 1800 pg/ml
for >75 years are recommended. Cautious interpretation of
concentrations is important in the presence of confounders such
as age; obesity; and cardiac, pulmonary, and renal disease.

69.  Circulating levels of natriuretic peptides are elevated
in HF with preserved ejection fraction (HFpEF), but
are lower in concentrations than in patients with
HFrEF. To support the diagnosis of HFpEF, partition
values for diagnosis are a BNP ≥100 pg/ml and
NT-proBNP ≥800 pg/ml.
 Changes in microRNA 29a, and 133a are associated
with myocardial fibrosis in patients with HFpEF, but
these have not been applied as diagnostic or
prognostic biomarkers in such patients.

70. Biomarkers for Prognosis of Chronic HF:
Elevated BNP or NT-proBNP parallel HF disease severity,
assessment of New York Heart Association (NYHA) class,
elevated filling pressures, or worse hemodynamics are
suggestive of worse clinical outcomes and mortality in HF.
Each increase in BNP by 100 pg/ml is associated with a
35% increase in relative risk of mortality (95% confidence
interval [CI], 22-49; p = 0.096). Detectable levels of hs-Tn
level predict worse outcomes including mortality (hazard
ratio, 2.08; 95% CI, 1.72-2.52) at 2 years.

71. Biomarkers for Prognosis of Acute HF
In patients with acutely decompensated HF, measurement of
BNP or NT-proBNP and cardiac Tn at the time of presentation is
useful for establishing prognosis or disease severity.
Predischarge BNP and NT-pro-BNP are stronger markers of
post-discharge outcomes than either baseline or percent
change in BNP during hospitalization.

72. Outpatient Management of HF
Biomarker–guided, with either BNP- or NT-proBNP, HF
therapy is of uncertain benefit in clinical practice and therefore
not advised.
The utility of serial measurement of BNP or NT-proBNP to
reduce HF hospitalization or mortality is not well established.