Cardica Biomarkers

1. CARDIAC BIOMARKERS
BY
Mr.Sandip Kanazariya
1

2. BIOMARKER
“A biomarker is a substance used as an
indicator of a biologic state”.
Morrow and de lomos three criteria
for biomarkers
– Accurate repeated measurements at
reasonable cost
– Must provide additional information
– Should aid treatment
2

3. HEART FAILURE
Heart failure a major and growing health problem
appears to result not only from cardiac overload or
injury but also from complex interplay among genetic,
inflammatory and biological changes acting on cardiac
myocytes, the cardiac interstitium or both.
ACUTE MYOCARDIAL INFARCTION
A sudden occlusion of a coronary artey by
thrombus or by embolisation causes an acute
myocardial infarction.
3

4. CARDIAC BIOMARKERS
• Cardiac biomarkers are protein molecules released
into the blood stream from damaged heart muscle
• Since ECG…… inconclusive ….biomarkers !!!!!?????
myocardial injury
• These biomarkers have a characteristic rise and fall
pattern
4

5. CHARACTERISTICS OF AN IDEAL
CARDIAC MARKER
• High cardiac specificity
• Pharmacokinetics of cardiac biomarker
• Easy diagnosis
• Marker should play a designed role in the treatment
and management of clinical subject
5

6. 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
6

7. CLASSIFICATION OF
CARDIAC BIOMARKERS
• Biomarkers of myocardial injury
– markers of myocardial necrosis
– markers of myocardial ischemia
• Biomarkers of haemodynamic stress
• Inflammatory and prognostic
Biomarkers
7

8. 8

9. BIOMARKERS OF
MYOCARDIAL INJURY
• Markers of myocardial necrosis
– Creatine kinase – MB
– Myoglobin
– Cardiac troponins
• Markers of myocardial ischemia
Ischemia Modified Albumin (IMA)
Heart-type fatty acid binding protein (H-FABP)
9

10. 10

11. 11

12. Zones of Ischemia Injury and Infarction with
Transmural and Subendocardial Infarction
12

13. CREATINE KINASE
Creatine kinase (CK/CPK) is an enzyme expressed in a
number of tissues.
Function: it catalyses the conversion of creatine to
phosphocreatine degrading ATP to ADP
The CK enzyme consists of two subunits, B (brain type) or
M (muscle type), Making three different isoenzymes: CK-MM,
CK-BB and CK-MB
• CK-BB occurs mainly in tissues, rarely of any significance in the
bloodstream
• Skeletal muscle expresses CK-MM (98%) and low levels of CK-
MB (1%)
• The myocardium has CK-MM at 70% and CK-MB at ~30%
13

14. CK-MB
• High specificity for cardiac tissue
• Begins to rise 4-6 hours after onset of infarction
• Peaks at about 12 hours
• Returns to baseline at 24-36 hours
• Can be used to indicate early re-infarction if level
normalizes and then increases again
14

15. DETECTION
• CK-MB now measured via a highly sensitive monoclonal antibody
assay
• Immunological Sandwich technique using two Abs for different
epitopes of CK –MB molecule
• The first Ab is rendered immobile on a matrix (e.g. CrO2
particles)
• The second Ab conjugate to an enzyme (β- galacto- sidase)
• Separated bound sandwiches are reacted with their substrate
(e.g. Chlorophenol β- Red Galactopyranoside)
• Liberated end product chlorophenol is measured
spectrophotometrically and is proportionate to CK-MB amount
(not the activity)
15

16. 16

17. DETECTION
• The CK-MB isoforms may also be analyzed using high-
voltage electrophoresis
• The ratio of MB2/MB1 is calculated
• MB2 released from heart muscle and converted to MB1
• A level of MB2 > or = 1 and a ratio of MB2/MB1 > 1.5
indicates myocardial injury
• A result is positive if MB2 is elevated and the ratio is
more than 1.5
17

18. 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…
18

19. MYOGLOBIN
• Small-size heme protein found in all tissues mainly assists in
oxygen transport
• It is released from all damaged tissues
• Increases often occur more rapidly than TI and CK
• Released from damaged tissue within 1 hour
• Normal value: 17.4-105.7 ng/ml
• Timing:
– Earliest Rise: 1-3 hrs
– Peak 6-9 hrs
– Return to normal: 12 hrs
19

20. CONDITIONS FOR MYOGLOBIN
INCREASE
• Acute myocardial infarction
• Skeletal muscle damage, muscular
dystrophy, inflammatory myopathies
• Renal failure, severe uremia
• Shock and trauma
20

21. CLINICAL USEFULNESS OF
MYOGLOBIN
• Rapid monitor of success of thrombolytic therapy
• Negative predictor of MI
DRAWBACKS
• Due to poor specificity, myoglobin levels do not
always predict myocardial injury
• Not utilized often for AMI/cardiac damage
assessment because of its very rapid metabolism
21

22. CARDIAC TROPONINS
• Troponin is a complex of three regulatory proteins that is
integral to non-smooth muscle contraction in skeletal as well as
cardiac muscle
• Troponin is attached to the tropomyosin sitting in the groove
between actin filaments in muscle tissue
• Troponin has three subunits, TnC, TnT, and TnI
– Troponin-C has calcium binding ability and has no diagnostic
value
– Troponin-T binds the troponin tropomyosin complex,
– Troponin-I is an inhibitory protein
22

23. 23

24. Cardiac Troponin Release after MI
24

25. TROPONIN I
1. Cardiac Troponin I (cTnl) is a cardiac muscle protein with a
molecular weight of 24 kilo-Daltons.
2. The cTnl has a additional amino acid residues on its N-
terminal that are not exist on the skeletal form.
3. The half life = 2~4 hours.
4. Serum increase = 2-8 hours
25

26. 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.
26

27. TROPONIN LEVELS
• Less than 5% in cytosol
• Troponin levels begin to rise 2-3 hours after onset of
myocardial injury
• Elevations in Troponin-I and Troponin-T can persist for up
to 10 days after MI
• Remember, CK-MB returns to baseline by 48 hours
• Thus far, studies have failed to find a source of Troponin-
I outside the heart, but have found some Troponin-T in
skeletal muscle
27

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

29. COMPARISON
29

30. Conditions commonly associated with cardiac troponin
elevations
• Arrhythmias
• Congestive heart failure
• Coronary artery disease
• Coronary vasospasm
• Critically ill patient
• Hypertension
• Myocarditis
• Pericarditis
• Pulmonary embolism
• Pulmonary hypertension, severe
• Renal failure
• Sepsis/septic shock
• Sepsis-related myocardial dysfunction
• Systemic inflammatory diseases
• Trauma
30

31. 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
31

32. 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)
32

33. DIAGNOSIS BASED ON SENSITIVE
TROPONIN I ASSAY
They used the concentration of 0.04 ng per mL
as the upper reference limit and established the
diagnosis of myocardial infarction if one value of
more than 0.04 ng per mL was documented,
combined with a rise or fall in the value of 30% or
more within 6 hours after admission.
Patients with troponin rises benefit more from
Glycoprotein IIb IIIa inhibitors such as,
• Abciximab
• Eptifibatin
• Clopidogrel
33

34. IN VETERINARY USE
• Most commonly used in dogs and cats
Clinical conditions
• Congestive heart failure
• Percardial disease
• Doxorubicin toxicity
• Gastric dilatation and volvulus etc,.
34

35. Fonflora et al study
120 animals were examined in emergency
with cardiac troponin assays,
• First group= ctni less than .15ng/ml
• Second group= ctni .15-1 ng/ml
• Third group= ctni more than 1 ng/ml
Prognosis grave in second and third group
35

36. 36

37. BIOMARKERS OF
MYOCARDIAL ISCHEMIA
37

38. Ischemia Modified Albumin
(IMA)
• A novel marker of ischemia, is produced when circulating
serum albumin contacts ischemic heart tissues
• IMA can be measured by the albumin cobalt binding (ACB)
assay that is based on IMA's inability to bind to cobalt
• Mechanism- due to structural change in the amino terminal
end of albumin
• IMA levels rise within 6 hours
• remain elevated for 12 hours
38

39. Drawbacks
IMA levels raised in non- cardiac ischemia
Modification to n- terminal end may also be
induced by extracellular hypoxia, acidosis etc,
Conclusion
FDA in 2010 has approved a multimarker approach
for using the combination of ECG, the cTnI, and the
IMA levels achieving a sensitivity of 95% for ACS
39

40. Heart-type fatty acid binding protein (H-FABP)
• H-FABP is a very stable abundant [138] low molecularweight
protein (14–15 kDa) in the cytoplasm of myocardial cells
• Appearing as early as 90 min after symptom onset and peaking
within 6 h
• Parameters of kinetic release make it an ideal candidate both for
early assessment or exclusion of AMI and for the measurement of
a recurrent infarction
40

41. • A study by Puls et al
– the negative predictive value (NPV) of H-FABP was
an impressive 100%
– its Positive predictive value was 41% which was
greater than that of both cTnT (29%) and NT-
proBNP (19%).
• The myoglobin/heart FABP ratio has been used to
differentiate between heart muscle and skeletal
muscle injury
• Cardiodetect
41

42. BIOMARKERS OF
HAEMODYNAMIC STRESS
42

43. NATRIURETIC PEPTIDES
43

44. NATRIURETIC PEPTIDES
• The natriuretic peptides (NP) are a group of
structurally similar but genetically distinct
peptides.
• NPs are identified as regulatory diuretic-natriuretic
substances responsible for salt and water
homeostasis
• Lowers blood pressure.
44

45. • The NP family includes
ANP : -atrial natriuretic peptide (28 a.a.)
N-terminal proANP (98 a.a.)
BNP : brain natriuretic peptide (32 a.a.)
N-terminal proBNP (76 a.a.)
CNP : C-type natriuretic peptide (22 and 53 a.a.)
45

46. Fig. Schematic representation of the ANP and BNP precursors with sequence
numbering defining low-molecular-mass forms, N-terminal forms and high-
molecular-mass precursors
46

47. NATRIURETIC PEPTIDES
• ANP is released primarily in response to atrial
wall stretching and intravascular volume
expansion.
• BNP is mainly secreted by the ventricles
• CNP is found predominantly in the brain and
also synthesized by vascular endothelial cells
47

48. BRAIN NATRIURETIC PEPTIDE
(BNP)
• originally isolated from porcine brain
• Subsequently also isolated from human heart
• Circulating levels of BNP are raised in patients
with cardiovascular or renal disease
• More important than ANP in heart failure
• Greatest proportion of circulating BNP is
thought to come from the ventricles (left)
48

49. • Synthesis
Synthesis in myocytes
49

50. Natriuretic peptide receptor
Three receptors for natriuretic peptides :
Natriuretic peptide receptor -A
Natriuretic peptide receptor -B
Natriuretic peptide receptor -C
NPR-A and NPR-B
• NPR-A and NPR-B are particulate guanylyl cyclases that
catalyses the conversion of GTP to c-GMP
• NPR-C
They lack the guanyl cyclase domain and may influence the
target cell function through inhibitory guanine nucleotide (Gi)
protein, and they likely also act as clearance receptors for
circulating peptides.
50

51. RECEPTORS AND
METABOLISM
NPR-A and NPR-B
• NPR- A is the most abundant type in
large blood vessels
• NPR-B predominate in the brain
• Both receptors are present in the
adrenal glands and the kidney
• Affinity
for NPR-A : ANP > BNP > CNP
for NPR-B : CNP > BNP > ANP
51

52. Action of Atrial Natriuretic Peptide at Target Cells
52

53. FUNCTIONS
• ANP and BNP concentrations increase in
response to volume expansion and pressure
overload of the heart
• ANP and BNP have been shown to be
physiological antagonists of the effects of
(1) angiotensin II on vascular tone
(2) aldosterone secretion
(3) renal-tubule sodium reabsorption
(4) vascular-cell growth
53

54. Natriuretic Peptides
54

55. Figure . Physiology of the natriuretic-peptide family
55

56. • Clearance factors for natriuretic peptides
NPR-C and neutral endopeptidase
Endopeptidase
• Neutral endopeptidase inactivates all
three natriuretic peptides
• Present within renal tubular cells and
vascular cells
56

57. Conditions or factors commonly associated with B-type
natriuretic peptide or N-terminal-pro-B-type natriuretic
peptide
elevations
• Age
• Arrhythmias
• Cardiomyopathy: hypertrophic, ischemic, or dilated
• Congestive heart failure
• Coronary artery disease
• Gender
• Hypertension
• Left ventricular diastolic dysfunction
• Pulmonary embolism
• Renal failure
• Right heart failure
• Right ventricular overloading: fluid, or pressure overloading
• Sepsis or septic shock
• Sepsis-related myocardial dysfunction
57

58. Breathing Not Properly (BNP)
study
• Prospective study of 1586 patients presenting to the emergency department
with acute dyspnea
Outcomes of the study
• The predictive value of BNP much superior to previous standards including
radiographic, clinical exam, or Framingham Criteria
• Bnp cut point was fixed at 100pg/ml and it showed 90% sensitivity and 80%
specificity for diagnosing heart failure
Veterinary field
• Chronic left ventricular systolic and diastolic dysfunction
• Cardiac vs non- cardiac dyspnoea
• Recent development of ELISA kits for canine and feline NTproBNPby
Guildhay Ltd (www. guildhay. Co.uk)
58

59. Therapeutic potential
ANP and BNP infusion
• Decrease renin and aldosterone
concentration
• Increase urinary sodium and water
excretion
Neutralendopeptidase inhibitor
• Nesiritide is a new drug that is a
synthetic BNP that vasodilates vessels
and serves as a potent diuretic agent
59

60. BNP for Rx of decompensated heart
failure Nesiritide (h-BNP)
32 amino acid sequence
Recombinant technology using E-coli
D
R I
M
K
R
G
S S
S
S
G
L
G
F
C
C
S S
G
SGQVM
K V L R
R
H
KPS
NOTE: hBNP affects assay for BNP, but can still use proBNP or one of the proANP assays
60

61. BIOMARKERS OF
INFLAMMATION
PROGNOSTIC MARKERS
AND MARKERS OF RISK
STRATIFICATION
61

62. •C-reactive protein
•Myeloperoxidase
•Homocysteine
62

63. 63

64. C-REACTIVE PROTEIN
• CRP is an acute-phase protein produced by
the liver
• Pentameric structure consisting of five 23-
kDa identical subunits
• Plasma levels can increase rapidly to
10000x levels
• High-sensitivity CRP (hs-CRP) assays
64

65. 65

66. • CRP previously known to be a marker of high
risk in cardiovascular disease
• More recent data may implicate CRP as an
actual mediator of atherogenesis
Mechanism of CRP-mediated atherogenesis:
• Once ligand-bound, CRP can:
– Activate the classical compliment pathway
– Stimulate phagocytosis
– Bind to immunoglobulin receptors
– Endothelial dysfunction via ↑ NO synthesis
– ↑LDL deposition in plaque by CRP-stimulated macrophages
66

67. 67

68. 68

69. Clinical Uses
– Screening for cardiovascular risk in
otherwise “healthy” individuals
– Predictive value of CRP levels for disease
severity in pre-existing Coronary artery
disease
Elevated levels predictive of
• Long-term risk of first MI
• Ischemic stroke
69

70. Limitations of CRP
• Low specificity
• No evidence that lowering CRP levels decreases CV risk
Industry and FDA staff guidelines 2005 had given clinical cut
off value as less than 1 mg/l as safe levels with hs-CRP
tests
CRP Risk for CVD
Less than 1.0 mg/L Low
1.0-2.9 mg/L Intermediate
Greater than 3.0 mg/L High
70

71. MYELOPEROXIDASE
• MPO is an enzyme that aids white blood cells
in destroying bacteria and viral particles
• MPO catalyzes the conversion of hydrogen
peroxide and chloride ions (Cl-) into
hypochlorous acid
• MPO is released in response to infection and
inflammation
• EPIC Norfolk Study
Sugiyama Am J Pathology 2001
71

72. • MPO leads to oxidized LDL cholesterol
– Oxidized LDL is phagocytosed by macrophages
producing foam cells
• MPO leads to the consumption of nitric oxide
– Vasoconstriction and endothelial dysfunction
• MPO can cause endothelial denuding and
superficial platelet aggregation
• MPO indicates activated immune cells
– Activated immune cells and inflammation lead
to unstable plaque
• Inflammatory plaque is inherently less stable
– Thin fibrous cap/fissured/denuded
72

73. 73

74. • In august 2005, FDA approved the first
MPO assay, Cardio MPO tm developed by
Prognostix,inc.
• The test is a sandwich enzyme immuno
assay
• Normal plasma MPO levels are 51-
633pmol/ml
74

75. Progression of Biomarkers in ACS
ACS, acute coronary syndrome; UA, unstable angina; NSTEMI, non–ST-segment elevation myocardial infarction; STEMI, ST-segment
elevation myocardial infarction
Adapted from: Apple Clinical Chemistry March 2005
STEMIUA/NSTEMISTABLE CAD PLAQUE RUPTURE
MPO
CRP
IL-6
MPO
ICAM
sCD40L
PAPP-A
MPO
D-dimer
IMA
FABP
TnI
TnT
Myoglobin
CKMB
Inflammation has been linked to the development of
vulnerable plaque and to plaque rupture

76. HOMOCYSTEINE
• Intermediary amino acid formed by the
conversion of methionine to cysteine
• Moderate hyperhomocysteinemia occurs in
5-7% of the population
• Recognized as an independent risk factor
for the development of atherosclerotic
vascular disease and venous thrombosis
• Can result from genetic defects, drugs,
vitamin deficiencies
76

77. • Homocysteine implicated directly in
vascular injury including:
– Intimal thickening
– Disruption of elastic lamina
– Smooth muscle hypertrophy
– Platelet aggregation
• Vascular injury induced by leukocyte
recruitment, foam cell formation, and
inhibition of NO synthesis
• Normal levels less than 6micro mol/l
77

78. • Elevated levels appear to be an
independent risk factor, though less
important than the classic CV risk
factors
• Treatment includes supplementation with
folate, B6 and B12
78

79. 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
79

80. 80

81. BIOMARKERS OF INTEREST,
ALTHOUGH THEY ARE NOT
CURRENTLY USED ROUTINELY
1. Serum Amyloid Protein A
2. sCD40 Ligand
3. Cytokines
4. Lipoprotein-Associated Phospholipase A2
5. Pregnancy-Associated Plasma Protein A
6. Oxidized LDL
7. Placental Growth Factor
8. Matrix Metalloproteinases
9. Monocyte Chemotactic Protein
10. Tissue Plasminogen Activator Antigen (t-PA) and Plasminogen Activator
Inhibitor 1 (PAI-1)
11. Secreted Platelet Granular Substances
12. Isoprostanes
13. Urinary Thromboxane
14. Adhesion Molecules 81

82. Serum Amyloid Protein A
• Serum amyloid protein A, an acute-phase
protein and an apolipoprotein, has been used
with hsCRP in cross-sectional studies.
• It can be synergistic with hsCRP326 but is
much less commonly used.
• At present, no standardized assays, reference
interval studies, nor consistent assay
validations are available.
82

83. sCD40 Ligand
• CD40 ligand is a transmembrane protein related
to TNF.
• It has multiple prothrombotic and proatherogenic
effects.
• What is usually measured is the soluble form of
the receptor, sCD40 ligand, which has been
shown to be a predictor of events after acute
presentation.
• At present, standardized assays, reference
interval studies, nor consistent assay validations
are not available.
83

84. Cytokines
• A variety of stimulatory and inhibitory interleukins
(TNF, IL-1, IL-6, IL-8, IL-12, IL-18) are thought to help
mediate the elaboration of CRP and the development
of atherosclerosis and acute events.121 These
cytokines may stimulate or inhibit leukocytes, often
through T cell–mediated processes and effects on
monocytes, which are indigenous to atherogenesis.
• In some studies, IL-6 is more prognostic than hsCRP.
• These cytokines often have inhibitors and/or binding
proteins that modulate their effects. At present,
standardized assays, reference intervals studies, and
consistent assay validations are not available.
84

85. Lipoprotein-Associated Phospholipase
A2
• Phospholipase A2 (Lp-PLA2) is a phospholipase associated
with LDL that is thought to be an inflammatory marker.
• It was previously known as platelet-activating factor (PAF)
acetyl hydrolase.
• It is synthesized by monocytes and lymphocytes and is
thought to cleave oxidized lipids to produce lipid fragments
that are more atherogenic and that increase endothelial
adhesion.
• An FDA-approved assay for this analyte includes obligatory
reference intervals.
• It has been shown to be predictive of events in a primary
prevention cohort, even when hsCRP is present in the
model, suggesting that it measures something different
from what is measured by the acute-phase reactants
associated with hsCRP. 85

86. Pregnancy-Associated Plasma Protein
A
• Pregnancy-associated plasma protein A (PAPP-A) is a
metalloproteinase that is thought to be expressed in
plaques that may be prone to rupture.
• The literature in this regard is mixed at present
concerning its use.
• At present, standardize assays, reference interval
studies, and consistent assay validations are not
available.
• Recent data suggest that heparin administration in MI
patients is associated with increased PAPP-A
concentrations; this may limit its prognostic role.
86

87. Oxidized LDL
• Oxidized LDL has been attributed a key role in the
development of atherosclerosis.
• Several methods have been used to measure it,
but they yield potentially different data.
• Some have correlated malondialdehyde LDL with
the development of atherosclerosis and short-
term events.
• Direct identification with antibodies suggests that
oxidized LDL may be released from vessels and
may colocalize with lipoprotein a [Lp(a)] after
acute events.
87

88. Placental Growth Factor
• Placental growth factor is an angiogenic factor
related to vascular endothelial growth factor
(VEGF), which stimulates smooth muscle cells and
macrophages.
• It also increases TNF and MCP-1. A novel assay
for this analyte is thought to provide additional
prognostic information on patients who present
with ACS.
• At present, standardized assays, reference
interval studies, and consistent assay validations
are not available.
88

89. Matrix Metalloproteinases
• Matrix metalloproteinases (MMPs) can degrade the collagen matrix
in coronary artery or myocardium.
• They are integral to remodeling of the coronary artery and/or the
heart after acute events.
• Elaboration of MMP-9, a gelatinase, is thought to be important in
plaque destabilization; thus some have tried to measure it as a
prognostic index.
• Other MMPs participate in the elaboration of extracellular matrix in
the heart.
• Many MMPs also have inhibitors [tissue inhibitors of
metalloproteinase (TIMPs)] that modulate their effects.
• At present, standardized assays, reference intervals studies, and
• consistent assay validations are not available.
89

90. Monocyte Chemotactic Protein
• Monocyte chemotactic protein (MCP-1) is a
chemokine that is thought to be responsible for
the recruitment of monocytes into
atherosclerotic plaque.
• It has been reported to be elevated in patients
with ACS and to have long-term predictive value.
• However, at present, standardized assays,
reference interval studies, and consistent assay
validations are not available
90

91. Tissue Plasminogen Activator Antigen (t-PA) and
Plasminogen Activator Inhibitor 1 (PAI-1)
• t-PA is the body’s physiologic fibrinolytic activator.
• PAI-1, its endogenous inhibitor, binds to t-PA.
• Inhibition of fibrinolysis has been suggested to be a
reason for recurrent infarction; the fact that maximal
inhibition usually occurs in the early morning hours
provides a potential explanation for the circadian
variability of AMI.
• It may also be the reason why persons with diabetes
have such unstable disease; the growth factor
properties of insulin stimulate increases in PAI-1.
• An accurate assessment of this system includes both t-
PA and PAI-1, along with some assessment of bound
versus free levels.
91

92. Secreted Platelet Granular Substances
• Both platelet factor 4 (PF4) and beta thromboglobulin
(BTG) are secreted when platelets aggregate.
• PF4 has a short half-life and is released by heparin.
• BTG is not released by heparin and has a longer half-
life.
• Both markers have been used to assess platelet
aggregation.
• BTG is by far the more reliable.
• At present, standardized assays, reference interval
studies, and consistent assay validations are not
available.
92

93. Isoprostanes
• Isoprostanes are the end breakdown products of lipid
peroxidation, and urinary levels have been used to
assess the level of oxidative stress.
• It is thought that oxidation of LDL is essential for the
development of atherosclerosis, and that HDL and
other antioxidants work by antagonizing this oxidative
stress.
• Urinary isoprostanes give some assessment of this
critical process.
• The most commonly measured are F2-isoprostanes,
but a large number of others are available for
measurement.
• It does appear that they will eventually be helpful in
assessing oxidative stress.
93

94. Urinary Thromboxane
• Urinary thromboxane is the end metabolite of
thromboxane A2, which is a measure of
platelet aggregation.
• Urinary levels are elevated in patients with
unstable coronary disease, in keeping with the
known participation of platelets in the
pathogenesis of CAD. This level is difficult to
ascertain, and collecting urine in the acute
situation is at times problematic.
94

95. Adhesion Molecules
• Adhesion molecules are a wide variety of molecules
that can potentially be measured as a way of assessing
the adherence of leukocytes and/or platelets or other
adhesive proteins to the endothelial matrix. Some are
receptors.
Examples
• include PECAM-1 (platelet-endothelial adhesion
molecule 1), P-selectin, e-selectin, and VCAM-1
(vascular cell adhesion molecule 1).
• At times, the receptor itself is measured, but often it is
a soluble portion that circulates that is measured.
• At present, standardized assays, reference interval
studies, and consistent assay validations are not
available 95

96. Choline
• Choline is released after stimulation by
phospholipase D and has been touted as a test
of prognosis in patients with chest discomfort.
• At present, standardized assays, reference
interval studies, and consistent assay
validations are not available.
96

97. Unbound Free Fatty Acid
• Unbound free fatty acid (uFFA)39 has also
been touted as a marker of ischemia.
• Most fatty acid is bound, and ischemia is
thought to increase the small unbound
fraction.
• Initial studies have reported mixed results.
• At present, standardized assays, reference
interval studies, and consistent assay
validations are not available.
97

98. Nourin
• Nourin I is a small protein released rapidly by
“stressed myocytes.”
• It induces changes in a variety of inflammatory
cytokines and attracts neutrophils.
• Preliminary studies have been done to
attempt to validate its use.
• At present, standardized assays, reference
interval studies, and consistent assay
validations are not available.
98

99. Copeptin
• Copeptin, a 30 amino acid glycoprotein constituting the
C-terminal portion of arginine vasopressin, has been
shown to be a prognostic biomarker in hemorrhagic
and septic sepsis.
• More recently, data have shown that measurement of
copeptin serves as a rapid and early rule-out biomarker
for AMI at presentation in patients with symptoms
suggestive of ACS with a normal cTn value.
• An assay measuring copeptin (CT-proAVP) has been
described using the Brahms Kryptor Immunology
Analyzer, Diamond Diagnostics Holliston, MA.
• Additional clinical and analytical validation studies will
be necessary, especially head-to-head comparisons of
copeptin versus the new hs-cTn assays.
99

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105

106. THANK U
106