Copy of Cardiac Troponin Assay-utility in Early Detection of Acs

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CARDIAC TROPONINARDIAC TROPONINASSAY-UTILITY INSSAY-UTILITY INDIAGNOSIS OFIAGNOSIS OF ACUTECORONARY SYNDROME

By

Dr.Anup Bhandari

JR 1 ,Department of Pathology,

S.R.T.R.M.C.Ambajogai


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Definitionefinition

Abiomarkeriomarker is a substance usedas an indicator of a biologic state.

It is a characteristic that isobjectively measured and

evaluated as an indicator of

normal biologic processes,

pathogenic processes, or

pharmacologic responses to a

therapeutic intervention.

--Wiki edia


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NEEDEEDBIOMARKERIOMARKERSTUDY INTUDY IN

ACUTECUTECORONARYORONARYSYNDROMEYNDROME?


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I t s bec ause;t s bec ause; neither the clinicalneither the clinical

presentation nor the ECGpresentation nor the ECGhad adequate clinicalhad adequate clinical

sensitivity and specificitysensitivity and specificityfor detecting MI without thefor detecting MI without theuse of biomarkersuse of biomarkers


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CONFOUNDING FACTORSONFOUNDING FACTORS For ECGor EC G preexisting ST-segment

elevation because of

ventricularaneurysm or by Q

waves

pacemaker rhythm

or preexisting or newly

developed bundle

branch blocks (BBB).

For clinicalor clinicalpresentationresentation

Gastroesophageal

disease

Pericarditis, pleuritis

Chest wall syndromes

Pulmonary embolism

Aortic aneurism

Herpes zoster


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What biomarkers arehat biomarkers aregood f orood f or

DiagnosingAMI/ACS

Detecting myocardial damagewhether due to AMI orother cardiac process

Risk-stratifyingpatients

Commenting onPrognosis

In ACS, pre and post PCI/reperfusion therapy

Renal Disease Stressing interns, confusing residents and worrying

cardiology fellows


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WhichhichBiomarkers?iomarkers? CK (CPK)

CK-MB

Troponin-I/T

LD (LDH)

Myoglobin

ALT/AST

Others


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CARDIAC ENZYMESARDIAC ENZYMES(BIOMARKERS)BIOMARKERS)

Most cardiac specific

TestTest Normal RangeNormal Range

CK or CPKCK or CPK

CreatinineCreatininePhosphokinasePhosphokinase

Normal 25-170 U/LNormal 25-170 U/L

CK-MBCK-MB < 5% MB< 5% MB

MyoglobinMyoglobin Normal < 85 ng/mlNormal < 85 ng/ml

LDHLDH(Lactate(Lactatedehydrogenase)dehydrogenase)

Normal 100-200 U/LNormal 100-200 U/LLDH-1 -5LDH-1 -5LDH- 1 is found primarily inLDH- 1 is found primarily inheart muscle and red bloodheart muscle and red bloodcells.cells.

TroponinTroponincTnTcTnT

Normal < 0.01ng/mlNormal < 0.01ng/mlMay be elevated by CRFMay be elevated by CRF

Troponin ITroponin IcTnIcTnI

Normal < 0.1 ng/mlNormal < 0.1 ng/mlNot elevated by CRFNot elevated by CRF


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Timing Summary

TEST ONSET PEAK DURATION

CK/CK-MB 3-12 hours 18-24 hours 36-48 hours

Troponins 3-12 hours 18-24 hours Up to 10 days

Myoglobin 1-4 hours 6-7 hours 24 hours

LDH 6-12 hours 24-48 hours 6-8 days


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Diagnosis f Acutegnos s cuteMyocardialyocardialInfarctionnfarction Typical rise and gradual fall (troponin) or

more rapid rise and fall (CK-MB)of

biochemical markers of myocardial

necrosis with at least one of the following:

ischemic symptoms;

development of pathologic Q waves on the

ECG;

ECG changes indicative of ischemia (STsegment elevation or depression);

coronary artery intervention (e.g., coronary

angioplasty)


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TROPONINROPONIN

Troponin is a complex of three regulatoryproteins 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

three subunits, TnC, TnT, and TnI Troponin-C (calcium ions)

Troponin-T (tropomyosin)

Troponin-I (actin)


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MORE ABOUTORE ABOUTTROPONINROPONIN Laboratory range definitionaboratory range definition :

Cutoff is set at 99th percentile of

a normal reference population,

variation of less than 10%

Since troponin levels are virtually

undetectable in normal

subjects, this 99th percentilecorresponds to


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Troponi n Useroponin Use

Therefore it has good utility for retrospectively

diagnosing AMI

Remember, CK-MB returns to baseline by 4 8 h o u r s8 h o u r s

Troponin

EarlyRise(hrs)

Peak(Hrs)

Duration(Days)

Specficity Sensitivity

Tn T 3-4 10-24 10-24 80% >98%

Tn I 4-6 1-24 4-7 95% >98%


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Troponin Influenceroponin Influenceon Prognosisn Prognosis


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Other than M.I .ther than M.I .c ondi ti onsondi ti ons C ardiac conditions-ardiac conditions- heart failure, myocarditis and pericarditis,

cardiomyopathy, cardiac contusion, defibrillation and

internal or external cardioversion,cardiac procedures

Non- cardiac conditions-on- cardiac conditions- critical illnesses such as sepsis, Several toxins and

venoms, Carbon monoxide poisoning , primary pulmonary

hypertension, pulmonary embolism and acute

exacerbations of chronic obstructive pulmonary disease

(COPD), Seizures, end-stage renal disease, Strenuous

endurance exercise


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Lab Detailsab D etai l s


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An immunoassay is a biochemical test that

measures the concentration of a substance inserum or urine, using the reaction of a

specific antibody(often monoclonal Ab) or

antibodies to bind to its antigen. To determine

a numerical result (as in cardiac biomarkers),the response of the fluid being measured

must be compared to standards of a known

concentration. One of the most common

methods is to label either the antigen or the

antibody with an enzyme(EIA), radioisotope

(RIA), magnetic labels(MIA) or fluorescence


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New molecules beingew molecules beingstudi ed;tudi ed;


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Edge over other biomarkers

improved time dependent sensitivity and

improved specificity

first peak value 40 times the detection limit VsCK-MB only 6-9 times

prognostic value of troponin in unstable

angina,reperfusion therapy

Corelates with infarct size

Reducing false positives


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ou!

Thanky

ou!

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Copy of Cardiac Troponin Assay-utility in Early Detection of Acs