Presentazione standard di PowerPoint · 2019-12-06 · •Disinformation •Poor knowledge of...

Overall, the worldwide combined measurement of cardiac troponins with creatine kinase MB (CK-MB) and/or myoglobin has been reported as high as 30%, with notable exceptions, even approximating 50%.

The reasons beyond this attitude are many and multifaceted, and basically include:• A well-known resistance to change• Disinformation• Poor knowledge of diagnostic performance of cardiac biomarkers• Personal persuasions that CK-MB and/or myoglobin would provide more useful clinical information than cardiac troponins• Cardiac troponins display a delayed kinetics compared to both CK-MB and/or myoglobin

1. Costs: With CK-MB no incremental information is

provided and such testing is not cost-effective

2. Quality: Quality control of CK-MB assays is difficult

3. Incorrect use: CK-MB is not being used

appropriately

4. Confusion: Using CK-MB keeps some clinicians

from learning how to use troponin properly and

effectively

It is time to learn how to use cardiac troponin properly

and, in doing so, let our old friend CK-MB rest in peace!

1. Present evidence supports elimination of CK-

MB and exclusive use of cTn to diagnose AMI,

identify reinfarction, and estimate infarct size.

2. CK-MB adds to the health care system financial

burden without adding value to patient care.

ACC/AHA Guidelines for the Management of Patients With Acute Myocardial Infarction.

The amino acid sequence of cardiac and

skeletal muscle isoforms of both troponin I and

troponin T (but not of troponin C) are sufficiently

different to allow the development of

monoclonal antibodies and relative

immunoassays reacting only with the

cardiospecific counterparts.

The name derives from their function:

• “I” in TnI stands for “inhibiting” the ATP-ase activity of

actomyosin,

• “T” in TnT stands for binding to “tropomyosin”

• “C” in TnC stands for binding “calcium” ions

Intracellular soluble pool of cardiac troponins only represents a minor amount of the total protein mass

contained in myocardial cells, typically comprised between:

• 7.5% for cTnT

• 8.3% for cTnI

Percentage of healthy population with measurable values

What does % of measurable values means?

Although the clinical information provided by the assessment of both cTn molecules may be incremental compared to that of either protein alone, their diverse release does not appear to be in response to different aetiologies of myocardial injury, but rather by the intrinsic biochemistry of cTnT and cTnI release and clearance in the circulation.

Prognostic value of troponins in patients with or without coronary heart disease: Is it dependent on structure and biology?Lippi G, Cervellin G, Sanchis-Gomar F. Heart Lung Circ, in press

The first commandment:Do not “mess up” the troponins!

Despite the role of cardiac troponins for

diagnosing myocardial ischemia is hence

unquestionable, a dilemma is still engaging

the minds of many clinicians and laboratory

professionals.

Is the measurement of one cardiac troponin

(i.e., cTnT or cTnI) better than the other?

Troponins share the same name, but…

… is one troponin (REALLY) like the other?

??

• Absolutely NO

… under a biochemical and biological perspective

• Absolutely YES

… under a clinical perspective