Pakistan Society of Chemical Pathologists Distance Learning Programme in Chemical Pathology Cardiac Biomarkers By Surg Commodore Aamir Ijaz MCPS, FCPS, FRCP (Edin) Professor of Pathology / Consultant Chemical Pathologist Bahria University Medical &Dental College / PNS SHIFA Karachi 19/02/2019 14:45

Q 1. A 49 year male has retrosternal chest pain of about 6 hours duration. His ECG shows ST elevation. You have received his serum sample for cardiac markers. Your FCPS Part II trainee has some queries regarding these tests: a. What test (s) will be suitable in this patient at this hour of his disease? b. What is the role of cardiac markers in the diagnosis of IHD in this patient? c. How these cardiac markers can help in prognosis and monitoring of this patient? 19/02/2019 14:45

Diagnosis of AMI Prolonged chest pain ECG changes Based on 2 out of 3 of WHO criteria (Circulation, 1979) Prolonged chest pain ECG changes Serum enzyme concentrations

New Criteria Based on ESC/ACC’s redefinition of MI (JACC, 2000) Typical rise and fall of Troponin or CKMB with one of the following: Ischemic symptoms Development of Q wave on ECG ST-segment elevation/depression Coronary artery intervention Pathologic (morphologic) findings of AMI

Ideal Marker to Detect AMI High concentration in myocardium Absence from non-myocardial tissues High sensitivity & specificity in circulation Rapid release into blood following myocardial injury Remains in blood several days to allow detection Blood levels correlate with extent of myocardial injury & prognosis Rapid, simple & automated commercial assays available Role designed for marker in diagnosis and management based on clinical studies & peer reviewed literature

Cardiac Markers of the 21Century MB (isoenzyme of CK) CKMM isoforms CKMB isoforms Myoglobin Troponin I Troponin T Associated Markers Brain natriuretic peptide Ischemia modified albumin C-reactive protein

Use of biomarkers in AMI / ACS : Diagnosis Detecting myocardial damage whether due to AMI or other cardiac process Risk-stratifying patients Commenting on Prognosis In ACS, pre and post Primary Intervention/reperfusion therapy CHF Renal Disease

Possible Answers to Q.1 CK-MB and Troponin (First mention both criteria). As per new criteria rise of CK-MB and /or Troponin is essential for the diagnosis of AMI. Assessment of prognosis, decision about Primary Coronary intervention (PCI) or reperfusion therapy, monitoring of reperfusion or PCI

Q 2. . You are a newly appointed Consultant Chemical Pathologist in a Lab. To your shear disappointment cardiac markers being carried out in this lab are CK, AST and LD. You want to change these markers with newer ones. a. Please name the cardiac markers you want to add instead of these older ones. b. Give THREE advantage of this replacement. 19/02/2019 14:45

AMI - diagnostics yesterday AST CK LDH HBDH Serumconcentration 1 5 6 7 3 2 4 Days after infarction Infarction

MI-diagnostics today 50 Myoglobin cTroponin 15 10 Multiples of upper reference value 5 Cut off 1 2 3 4 5 6 7 10 Infarction Days after infarction

Possible Answers to Q.2 CK-MB and Troponin I (or Troponin T) Total CK alone and AST has very low specificity while LD is not necessary now as Troponin remains high upto 10 days.

Q 3. A 52 year old male underwent abdominal surgery Q 3. A 52 year old male underwent abdominal surgery. At 2nd post operative day he developed some chest discomfort but his ECG was normal. His CK was 1755 U/L (RR: < 195) and CK-MB was 56 U/L (RR: < 25). Anaesthetist incharge of the case has sought your advice for answers of the following questions: a. What is the most probable cause of this enzyme change? b. “I have heard of MB index. How can we calculate it in this patient?” c. Any other cardiac marker which can be helpful in this patient? 19/02/2019 14:45

Limitation of CKMB FP incidents in perioperative patients without cardiac injury False elevations in Skeletal muscle injury Marathon runners Chronic renal failure Hypothyroidism MI detection not timely enough for thrombolytic intervention. MB peaking takes >12h

MB Index MB Index = (CKMB /total CK) x 100 Rationale for using MB Index Using CKMB alone (RR < 25 U/L) often yields False Positive results Combined use with MB Index helps to rule-out patients with skeletal muscle injury Recommended Cut Off: 6%

Possible Answers to Q.3 Muscular Injury MB index is CK-MB / CK x 100. In this patient it is 3.1% which is not consistent with AMI. In AMI it should be more than 6% (and above 25 U/L) Troponin I

Q 4. Troponins are new cardiac markers Q 4. Troponins are new cardiac markers. Before start of this service in the lab, please try to solve following issues: a. Name the methods of analysis available in our country. b. How will you determine cut off value of troponins? c. What is the recommended CV of the test? 19/02/2019 14:45

Troponins Regulatory proteins in striated muscle Responsible for calcium-modulated interaction Exist in a number of isoforms Cardiac specific forms immunologically separable Troponin T (TpnT) Troponin I (TpnI)

Defining Increased Troponin Tpn T and I are not detected in healthy persons Significant Tpn reflects myocardial necrosis Detectable Tpn but no  CKMB may indicate microinfarction Tpn identifies high-risk ACS patients for aggressive anti-thrombolytic therapy ACC/ESC defined Tpn as a measurement above 99th percentile value of reference group To reduce false-positive outcomes, CV of 10% at decision limit is recommended

Clinical Issues in New Guideline (Consensus document from ESC, ACC, AHA in Circulation, 2000) cardiac troponin reflects myocardial injury but do not indicate its mechanism Not synonymous with MI or ischemic mechanism of injury. Pursue other etiologies of myocardial injury Likely reflects irreversible injury Tpn after heart surgery; can’t differentiate injury caused by MI from procedural-induced injury

Possible Answers to Q.4 Immunological methods with measurement of activity Take human volunteers without any known heart disease and rank them in descending order. The level of the subject at 99th percentile should be taken as the cut-off. CV -10%

Q 5. A 44 year male patient has reported in A&E of hospital with Myocardial Infarction of 1 hour duration. The cardiac marker which will rise first is: a. CK-MB b. Creatinine Kinase (CK) c. Myoglobin d. Troponin I e. Troponin T c. Myoglobin 19/02/2019 14:45

Myoglobin & CKMB in typical MI 3 samples drawn within 2 h

IFCC & NACB Guidelines Early marker to be performed in ED  within 6 h, e.g. myoglobin. Good for r/o AMI Rapid triage & thrombolytic therapy if onset is within 6- 12 h Definitive marker 6-12 h, sensitive & specific, e.g. TpnT, TpnI Decision limits A low level suggestive of myocardial damage A high level suggestive of dx of AMI Perform both CKMB and Tpn’s for a period of time to understand the difference in Tns vs CKMB

Myoglobin as Cardiac Marker Collect at least 2 samples within 2h for myoglobin determination Calculate slope of myoglobin release Use 20 ng/mL/h as cut-off point

Q 6. A 71 year old male was admitted in Coronary Care Unit with suspected Congestive Cardiac Failure. The most helpful biochemical marker for the diagnosis of heart failure is: a. BNP b. Plasma Aldosterone c. Plasma Electrolytes d. Plasma Renin Activity e. Troponin T a. BNP 19/02/2019 14:45

Role of BNP Determination of biological standards for diagnosis, prognosis & treatment of HF B-Type Natriureteric Peptide (BNP) Amino-terminal propeptide equivalent, N- terminal-proBNP or NT–pro BNP Role in diagnosis of HF Useful in predicting outcomes To guide treatment out of reach for now The clinical introduction of testing for the natriuretic peptides, including BNP and NT-proBNP, has fueled interest in the determination of biological standards for diagnosis, prognosis determination, and treatment of HF. BNP and NT-proBNP have emerged as the workhorse biomarkers to aide in diagnosing HF These also have been established as useful in predicting outcomes. However using BNP or NT-proBNP to guide HF treatment remains out of reach for now. On a positive note James Januzzis research team recently published the results of a succesful NT-proBNP guided HF in Journal of American College of Cardiology 2011 vol58,in which therapy guided by NT-proBNP reduced hospitalization for HF by more than 50%.

Q 7. The advantage of performing Troponin over CK-MB is: a Q 7 The advantage of performing Troponin over CK-MB is: a. Also detects LVF b. Cardiac Specificity c. Cost Effectiveness d. Earlier rise e. User Friendly analysis b. Cardiac Specificity 19/02/2019 14:45

Troponin Release Kinetics Pattern of release in MI is BIPHASIC. Detectable in blood 4-12 h, similar to CKMB Peaks 12-38 h Remains elevated for 5-10 days

Q 8. IHD is a common problem in Patient of ESRD in hemodialysis unit Q 8. IHD is a common problem in Patient of ESRD in hemodialysis unit. Consultant Nephrologist has inquired about the appropriate cardiac markers in these patients with grossly impaired renal clearance. Which of the following markers is most suitable in these patients: a. CK-MB (mass) b. Heart-type fatty acid binding protein c. Myoglobin d. Troponin I e. Troponin T 19/02/2019 14:45 d. Troponin I

Biomarkers in Renal Failure 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 skeletal myopathy, intramuscular injections and reduced clearance CK-MB: 30-50% of dialysis patients exhibit an elevation in the MB fraction >5% without evidence of myocardial ischemia Therefore, the most specific marker for suspected AMI in ESRD patients is Troponin-I with an appropriate sequential rise

Q 9. A 55 years old male admitted in CCU for the management of MI Q 9. A 55 years old male admitted in CCU for the management of MI. On 3rd day he had fresh changes in his ECG which forced his treating Cardiologist to think of fresh attack of MI. Which will be the most appropriate test to rule out this second attack? a. CK-MB b. LD c. Myoglobin d. NT-Pro BNP e. Troponin I 19/02/2019 14:45 e. Troponin I

Monitoring Myocardial Reinfarction (clin chem, 2005) Tpns can remain elevated up to 5 - 10 d after AMI, usefulness in monitoring reinfarction questioned. CKMB may be more useful since elevation lasts 2-4 d Conclusion from comparative biomarker profiles study Tpn alone is sufficient to rule in and rule out MI and/or reinfarction in clinical practice. Reported incidence rate of reinfarction <20% Given the limited financial resources in laboratories and healthcare, clinicians should consider monitoring just cardiac troponins for the diagnosis of MI or in-hospital infarction.

Q 10. Markers of Oxidative stress include: a. Adiponectin b Q 10. Markers of Oxidative stress include: a. Adiponectin b. C–reactive protein c. Myeloperoxidase d. Troponins e. Tumour necrosis factor α 19/02/2019 14:45 c. Myeloperoxidase

Biomarkers of Oxidative Stress in HF Oxidized LDL Myeloperoxidase Urinary biopyrrins Lipoprotein-PhospholipaseA2 (LP-PLA2) Matrix Metalloprotienase2(MMP2) Tissue Inhibitor of Metalloproteinase1(TIMP1)

Carry Home Message Myocardial Infarction has been redefined with inclusion of Biomarkers (new) as essential component of diagnosis CK-MB is no longer the ideal cardiac marker, however, its use should be continued in conjunction with Trops CK-MB should be assayed alongwith total CK for calculation of MB Index Troponins I & T should be the cardiac markers of choice for diagnosis, evaluation of severity and monitoring.