What causes high troponin levels?

Troponin, composed of three subunits, T, C, and I, together with tropomyosin, regulates the interaction between actin and myosin by regulating the activity of calcium ions on the striated actin ATPase. When the myocardium is damaged, the cardiac troponin complex is released into the blood and begins to increase in the blood 4-6 hours later. The elevated troponin I can remain in the blood for a long time, 6-10 days. Troponin I has high myocardial specificity and sensitivity, so troponin has become the most ideal marker for myocardial infarction.

Troponin and tropomyosin together can regulate the interaction of calcium ions with rhabdomyosin. When the patient's myocardium is damaged, troponin levels will increase. This is also the most ideal marker of myocardial infarction at present. Through the examination of calcitonin, myocardial damage can be diagnosed and myocarditis can be well diagnosed.

1. Diagnosis of myocardial injury

Among the many clinical biochemical indicators for diagnosing acute myocardial infarction (AMI), CK-MB was once considered the "gold standard" for diagnosing AMI and has been widely used for many years. With the in-depth study of cardiac troponin (cTn), the status of CK-MB has been seriously challenged both in terms of its specificity for the myocardium and its diagnostic sensitivity. cTn is considered to be the best definitive marker currently and is gradually replacing CK-MB as the "gold standard" for the diagnosis of AMI.

2. Indicators of thrombolytic therapy after AMI

Intravenous injection of thrombolytic drugs has been a commonly used treatment method for AMI in recent years. Determining whether reperfusion occurs after treatment has also become one of the most concerned issues for clinicians.

3. Diagnosis of perioperative myocardial infarction

The diagnosis of myocardial infarction after coronary artery bypass grafting plays an important role in cardiac surgery. cTn is a sensitive and specific marker for perioperative myocardial infarction, which can identify minor perioperative myocardial damage that does not meet the conventional perioperative myocardial infarction criteria.

4. Diagnosis of myocarditis

Compared with CK activity, cTnT has a higher detection sensitivity in myocarditis due to its relatively high serum detection value and longer rise time. Serum cTnT can be used as a diagnostic marker for acute myocarditis.

5. Relationship with renal failure

Ischemic heart disease is one of the main causes of morbidity and mortality in patients with end-stage renal disease, accounting for approximately 40% of the total mortality; approximately 25% of these ischemic heart diseases develop into AMI.

6. Differential diagnosis from skeletal muscle injury

Cardiac and skeletal muscle cells are closely related. During the embryonic stage, the two muscles have many similarities in gene expression, but their expression diverges during terminal differentiation.