Lipid Profile test & Cardiac Markers for MBBS, Lab. Med. and Nursing.pptx

The lipid profile is a group of tests that have been shown to be good indicators of whether someone is likely to have a Coronary disease or heart attack or stroke caused by blockage of blood vessels or hardening of the arteries (atherosclerois).

1. Lipid Profile Test Lipid Panel; Coronary Risk Panel RAJENDRA DEV BHATT, PhD Scholar Asst. Professor Clinical Biochemistry and Laboratory Medicine Fellow: Translational Research (2018-2022) in CVD in Nepal, NHLBI & NIH, USA

2. What is a lipid profile Test ? The lipid profile is a group of tests that have been shown to be good indicators of whether someone is likely to have a Coronary disease or heart attack or stroke caused by blockage of blood vessels or hardening of the arteries ( atherosclerois ).

3. What is a lipid profile? The lipid profile typically includes: Total cholesterol High density lipoprotein cholesterol (HDL-C) — often called good cholesterol Low density lipoprotein cholesterol (LDL-C) —often called bad cholesterol Tri acylglycerol An extended profile may also include: Very low density lipoprotein cholesterol (VLDL-C) Non-HDL-C Lipoprotien ( a)- LPa Sometimes the report will include additional calculated values such as the Cholesterol/HDL ratio etc

4. Lipid Profile panel Test Serum Total Cholesterol (TC) HDL-Cholesterol (HDL-C) Triacylglycerol LDL-Cholesterol Calculated VLDL Non-HDL Cholestrol TC/HDL-C ratio TAG/HDL ratio LDL-C/HDL ratio

5. How is the sample collected for testing? Subject need to fast for 9-12 hours before blood is drawn; only water is permitted . Total and HDL-C levels are similar when fasting or non-fasting, but TAG should be measured after 12 to 14 hours of fasting. Serum TC and HDL-C can be done in random sample. TAG levels are inversely related to HDL-C levels. Diurnal variation causes TAG to be lowest in the morning and highest around noon.

6. CARDIAC BIOMARKERS

7. “A biomarker is a substance used as an indicator of a biologic al state ”. Morrow and D e L omos suggested three criteria for biomarkers Accurate repeated measurements at reasonable cost Must provide additional information Should aid treatment

8. An indicator used for objective measurement and evaluation of Response to therapeutic i nt e r v e n tion Pathogenic process Normal biological process

9. Characteristics of an ideal biomarker Standardized High Sensitivity and Specificity Accurate Reproducible Easy to interpret Consistent and Cost effective Has an impact on clinical/risk management

10. Rule out an acute MI Confirm an old MI (several days) Monitor the success of thrombolytic therapy Risk stratification of patients with unstable angina pectoris Risk stratification in apparently healthy persons is not done with cardiac markers, but by measurement and assessment of cardiac risk factors QUESTIONS MAY ANSWERED BY CARDIAC MARKERS

11. History of Cardiac Bio m a r k e r s 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

12. Cardiac biomarkers Cardiac biomarkers were first developed for assisting the cardiac events , especially acute myocardial infarction. Better understanding of cardiac disease process and advancement in detection technology has pushed the application of cardiac biomarkers beyond the diagnosis boundaries. Cardiac biomarkers are now used for staging of cardiac disease, timing of cardiac events and prognostification.

13. Markers of cardiac tissue damage Markers of myocardial function Cardiovascular risk factor markers Ge n e tic a na l y sis f or ca n did a t e g ene s o r ri sk factors CLASSIFICATION OF LABORATORY TESTS IN CARDIAC DISEASE

14. High s ensitivity C - R eactive P rotein ( hs -CRP) & H omocysteine Marker of Inflammation

15. CRP is Pentameric structure consisting of five identical subunits of 23-kDa. Its plasma levels can increase rapidly to 10,000x levels. It is the most extensively studied marker of inflammation. Despite some controversy regarding its clinical use, it appears to be the most promising to date. Although considered to be a general nonspecific marker of inflammation, elevated baseline levels of hsCRP are correlated with higher risk of future CV morbidity and mortality among those with or without clinical evidence of CVD. High-Sensitivity C-Reactive Protein

16. Clinical Uses Screening f or c a rdio v a scular r i sk i n oth e r w i s e “ h ea l t h y ” individuals Predictive value of CRP levels for disease severity in pre- existing Coronary artery disease Elevated levels are predictive of Long-term risk of first MI Ischemic stroke High-Sensitivity C-Reactive Protein

17. 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 Less than 1.0 mg/L 1.0-2.9 mg/L Greater than 3.0 mg/L Risk for CVD Low In t ermediate High Limitations of CRP

18. 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 H omocysteine

19. Homocysteine is implicated directly in vascular injury including: Intimal thickening Disruption of elastic lamina Smooth muscle hypertrophy Platelet aggregation Proposed mechanisms by which it induces vascular injury are leukocyte recruitment, foam cell formation, and inhibition of NO synthesis. Normal levels : 3.7 – 13.9 µmol/L Homocysteine

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

21. Marker of Mocardial Ischemia Ischemia Modified Albumin ( IMA ) and Heart type-fatty Acid Binding Protein ( H - F A B P )

22. Ischemia modified albumin is a marker formed after damage in the N terminal region of the albumin in ischemic conditions. This structural change leads to loss of its ability to bind with transitional metals (cu/co). Endothelial or extracellular hypoxia, acidosis and free oxygen radicals causes increase in IMA. IMA rises within minutes from onset of ischemia and remains elevated for several hours after cessation of ischemia. Ische m ia Modified Albumin

23. I t is used as diagnostic criteria for myocardial necrosis that develops after Coronary artery bypass graft surgery (CABG) . It is a non specific marker, since it is also reported to be elevated in pulmonary infarction, critical limb ischemia and cerebrovascular disorders. Basically, it is used to rule out ischemia rather than diagnosing the occurrence of ischemia. Which is helpful in differentiating pain of Angina from Myocardial ischemia. Clinical uses of IMA :

24. Heart type fatty acid binding protein is a very stable low molecular weight (14-15kDa) in the cytoplasm of myocardial cells. FABPs are involved in active fatty acid metabolism where it transports fatty acid from cell membrane to mitochondria for oxidation. Small size of H-FABP facilitates rapid diffusion through interstitial space, appearing as early as 1-3 hrs after onset and peaking within 6hrs. It return to normal levels with in 12-24hrs. Normal levels : 1.6 – 19 ng/ml H - F ABP

25. H-FABP is 20 times more specific to cardiac muscle than myoglobin H-FABP is recommended to be measured with troponin to identify MI and ACS in patient presenting with chest pain. In addition to its diagnostic potential H-FABP also has prognostic value. The risk associated with ↑ H-FABP is dependent upon its concentration. Patients who were cTnI normal but H-FABP high have more risk of morbidity and mortality after 1 year follow up than those with cTnI high but HFABP normal . H - F ABP

26. Marker for cardiac necrosis c T n CK- MB Myoglobin

27. Troponin is a complex of three regulatory proteins (Troponin C, Troponin I and Troponin T) that is associated with muscle contraction in skeletal and cardiac muscle. Cardiac troponin is slightly different from skeletal troponin structurally hence serve as a potent and specific marker for cardiac disease. Cardiac Troponins

28. THE TROPONIN REGULATORY COMPLEX

29. Individual subunits serve different functions: Troponin C binds to calcium ions to produce a conformational change in TnI Troponin T binds to tropomyosin, interlocking them to form a troponin-tropomyosin complex Troponin I binds to actin in thin myofilaments to hold the troponin-tropomyosin complex in place Usually, Troponin is not detectable in healthy individual. Cardiac Troponins

30. It is extremely useful in patients who do not seek attention in the 2 to 3 days window when CK-MB is elevated. Rise : with in few hours after onset of chest pain Peak : 2 days returns normal : 7-10 days cTnT may show a biphasic release in some patients with a first peak occurring during first 24 hr of onset of symptom and second peak on appx. 4 th day after admission. TnT has cardiac as well as skeletal muscle source. cTnT :

31. It is cardiac specific because it has additional amino acid residue on its N-terminal that are non existent in skeletal muscle. Rise : b/w 4-6 hr after onset of pain Peaks : 12-18 hrs Returns normal : 6 days Its measurement is advantageous over CK-MB as it is not found in detectable amount in serum of patients with multiple injuries, renal disease and in those with acute and chronic skeletal muscle disorders. cTnI :

32. Creatine kinase (CK) is a cytosolic enzyme involved with the transfer of energy in muscle metabolism. It catalyses the conversion of creatine to phospho-creatine degrading ATP to ADP. 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 CREATINE KINASE: CK-MB

33. CREATINE KINASE: CK-MB CK-MB is the most cardiac-specific CK isoenzyme Proportion of CK-MB varies in skeletal & cardiac muscle In normal population CK-MB < 6% Tot CK Sensitive marker with rapid rise & fall More specific than Tot CK but has limitations “Gold standard” biochemical marker for past few decades

34. It is a valuable tool for the diagnosis of MI because of its relative high specificity for myocardial damage. Rise : 4-6 hrs after onset of symptoms Peak : 12 hrs Return to normal : 24-36 hrs Can be used to indicate early re-infarction if level normalizes and then increases again. CK-MB :

35. 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 hour Normal value: 17.4-105.7 ng/ml Timing: Earliest Rise: Peak Return to normal: 1-4 hrs 6-9 hrs 12 hrs Myoglobin

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

37. *if myoglobin concentration remains within the reference range 8 hours after the onset of chest pain, AMI can be ruled out essentially. *because of its rapid clearance by the kidney, a persistently normal Mb concentration will rule out reinfarction in patient with recurrent chest pain after AMI *Rapid monitor of success of thrombolytic therapy DRAWBACKS Due to poor specificity, myoglobin levels do not always predict myocardial injury Clinical usefulness of myoglobin :

38. NEW GENERATION CARDIAC MARKERS M y o g lo b in Currently earliest marker Like total CK it is by no means cardio- specific T r op o nins Kinetics comparable with total CK and CK-MB Cardio-specific S e nsitivity S p ecificity

39. 2 3 4 5 7 6 myoglobin CK-MB c T n T cTnI Comparison of cTn, CK-MB , Mb 1 0 4 8 1 2 1 6 2 2 4 2 8 3 2 3 6 4 4 4 48 Time after onset of AMI (hours) Χ upper limit of reference interval

40. Marker for haemodynamic stress natriuretic peptides

41. The natriuretic peptides (NP) are a group of structurally similar but genetically distinct peptide hormone. It 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.) DNP : D- type natriuretic peptide The NPs play important role in regulation of salt and water balance (CV homeostasis) N atriuretic peptides

42. 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 natriuretic peptides

43. Circulating levels of BNP are raised in patients with cardiovascular or renal disease BNP is More important than ANP in heart failure Greatest proportion of circulating BNP is thought to come from the ventricles (left) BRAIN NATRIURETIC PEPTIDE (BNP)

44. BNP and the terminal fragment of its prohormone (NT-proBNP) are released on ventricular stretch or stress to the myocyte in the absence of the necrosis. Therefore, BNP is increased in diseases characterised by an expanded fluid volume (e.g. CHF, renal failure,hepatic cirrhosis etc.) BNP has ci r c u l a t i n g T ₁/₂ o f 20 mi nu t e s , so it is i n di c a ti v e of s n a p s h o t of m y oc a r dial fu n cti on, w h ile N T -p r oBNP has T ₁/₂ o f 90 mi nu t es giving a longer view of myocyte . BRAIN NATRIURETIC PEPTIDE (BNP)

45. SUMMARY “Cardiac Enzymes” are obsolete Medical & laboratory progress has required a redefinition of Cardiac Events C a r diac T r oponi n s & M y og l ob i n now p l a y a pi v o t a l r ole i n the diagnosis of AMI Cardiac Troponins play an important role in the risk stratification of ACS patients Elevated Troponin levels in patients without ECG changes & with normal CK-MB levels may identify patients at increased risk of cardiac events

46. 1. What is the earliest cardiac marker that can be detected ? Myoglobin CK-MB Cardiac Troponin I Cardiac Troponin T

47. 2. A biomarker is substance used as an……………. Of a biological state a. Inhibitor b. Indicator c. Cofactor d. None of these

48. 3. How many hours do troponin begin to rise ? 1 hour 2 hours 4 hours 8 hours

49. 4. What is the most sensitive and specific marker available today for AMI ? a. CKMB b. Myoglobin c. CKBB d. Troponin

50. 5. What is a marker for heart failure ? Myoglobin Troponin BNP CKMB

51. Future Cardiac Biomarker miRNA

52. miRNAs are appx. 20-25 nucleotide long non coding RNAs, that negatively regulate or inhibit gene expression by binding to sites in the untranslated regions of targeted messenger RNAs. miR N A