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Table 3 Time course of markers of Myocardial infarction Marker

Onset

Peak

Duration

Troponins

4-10 hr

18-24 hr

8-14 Days

CK-MB

3-6 hr

18-24 hr

36-48 hr

Myoglobin

1-4 hr

6-7 hr

24 hr

levels, and indeed, these patients had increased mortality. The best marker of ventricular dysfunction is pro-BNP. Commercial kits are available to assess the level of BNP as well as the amino terminal of the prohormone (NT-proBNP). Normal level of NT-proBNP is less than 400 ng/L. Less than 250 ng makes heart failure highly unlikely. RISK FACTORS FOR ATHEROSCLEROSIS Serum Cholesterol Level: In healthy persons, cholesterol level varies from 150 to 200 mg/dl. If other risk factors are present, cholesterol level should be kept preferably below 180 mg/dL. Values around 220 mg/dL will have moderate risk and values above 240 mg/dl will need active treatment. Females have a lower level of cholesterol which affords protection against atherosclerosis. Plasma cholesterol levels would tend to slowly rise after the 4th decade of life in men and postmenopausal women. For every 10% lowering of cholesterol, CHD mortality was reduced by 13%. Serum cholesterol level is increased in Diabetes mellitus, Obstructive jaundice, Hypothyroidism, Nephrotic syndrome and in Familial hyper lipoproteinemias. LDL-Cholesterol Level: Blood levels under 130 mg/dl are desirable. Levels between 130 and 159 are borderline; while above 160 mg/dl carry definite risk. Hence, LDL is ‘bad’ cholesterol. Recently, simple homogeneous assay for sd-LDL-cholesterol has been developed. HDL-Cholesterol Level: HDL level above 60 mg/dL protects against heart disease. Hence HDL is ‘good’ cholesterol. A level below 40 mg/dl increases the risk of CAD. For every 1 mg/dL drop in HDL, the risk of heart disease rises 3%. If the ratio of total cholesterol/HDL is more than 3.5, it is dangerous. Similarly, LDL: HDL ratio more than 2.5 is also detrimental. Apo-B-100 : It is the specific apopro tein present in LDL. Therefore, estimation of Apo-B concentration is a better way of identifying LDL level. Apo-A-1: High density lipoproteins trans-

port cholesterol from peripheral tissues to the liver. The major apoprotein in HDL is Apo-A. Therefore, estimation of Apo-A concentration is a better way of identifying HDL level. Apoprotein Levels and Ratios: Ratio of Apo B: A-I is the most reliable index. The ratio of 0.4 is very good; the ratio 1.4 has the highest risk of cardiovascular accidents. Non-HDL Cholesterol : Non HDL cholesterol or Atherogenic cholesterol is calculated as (LDL+ VLDL+ IDL+ Lpa). Values between 100-130 mg/dl carries very little risk, those of 130-160 mg/dl have border risk, values 160-190 mg/dl have high risk, while values more than 190 mg/dl carries very high risk. Lp(a) : Lipoprotein (a) or Lp(a) should not be confused with Apo-A. Lp(a) is very strongly associated with myocardial infarction. Lp(a),when present, is attached to LDL. In 20% of population, the Lp(a) concen-tra-tion in blood is more than 30 mg/ dl; and these persons are susceptible for heart attack at a younger age. Indians have a higher level of Lp(a) than Western populations. Lp(a) impairs fibrinolysis, leading to unopposed intravascular thrombosis and possible myocardial infarc-tion. Levels more than 30 mg/dl increase the risk 3 times; and when increased Lp(a) is associated with increased LDL, the risk is increased 6 times. Nicotinic acid will reduce serum Lp(a) level. High Sensitivity C Reactive Protein (hsCRP): It is also called ultra-sensitive CRP. It is a marker for risk for atherosclerosis and is used as a predictor for future myocardial infarction within the next 12 months. Less than 1 mg/L (0.1 mg /dl) is considered as low risk and single measurement is sufficient. Levels between 1-3 mg /L are border line, indicating some risk, and will need assessment of serial samples at one-week intervals. Levels more than 3 mg/L is having high risk for future MI and will need active medical intervention. Atherosclerosis has an inflammatory component, which causes production of CRP in small quantities. The CRP binds selectively to LDL, activates complement, resulting in plaque formation. Statin therapy is found to reduce hsCRP level as well as the incidence of MI. If the hsCRP value is more than 10 mg/L, it indicates significant acute phase reaction and is not indicative of any cardiac pathology, but indicates infections somewhere else. Thus, hsCRP is tested only when other inflammatory conditions are ruled out. If the hsCRP value is more than 10 mg/L, it indicates significant acute phase reaction and is not indicative of any cardiac pathology, but indicates infections somewhere else. Serum Triglyceride: Normal level is 50-150 mg/dL. Blood level more than 200 mg/dL is injurious to health.

TECHAGAPPE

APRIL-JUNE 2018

15

Techagappe 15th edition (April - June 2018) E-book  

Agappe Diagnostics Limited is the first Indian IVD company publishing an International Diagnostic News Journal “Techagappe” for the public t...

Techagappe 15th edition (April - June 2018) E-book  

Agappe Diagnostics Limited is the first Indian IVD company publishing an International Diagnostic News Journal “Techagappe” for the public t...

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