Why check cardiovascular markers
These are specific biochemical indicators of blood. Tests are ordered by cardiologists and often urgently due to a patient’s emergency, such as a heart attack. We tell you what they show, what they are and what to pay attention to.
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Why are they appointed
Laboratory markers of cardiovascular pathologies are tests that help complete the diagnosis or quickly respond to an emergency.
“When it comes to acute myocardial damage, first of all, the level of troponin is determined with a highly sensitive test system,” explains hematologist, therapist at Lakhta Clinic Maria Bushurova. “In Russia, the use of tests for myoglobin, creatine phosphokinase-MB fraction is traditionally continued, but to determine the time of myocardial damage, or in the absence of highly sensitive test systems for troponin.”
In the general blood test, there is no information about the state of the heart and blood vessels. Functional diagnostics is not always available, and sometimes more labor-intensive than laboratory analysis.
For analysis, venous blood is needed. The result of the laboratory is evaluated by a cardiologist. They help to choose the right treatment and make a prognosis for the patient. These are not the tests that are given for prevention and screening once a year, only against the background of complaints and corresponding symptoms: shortness of breath, pain in the heart, swelling.
“In chronic heart disease, it is important to do a lipid profile and donate glucose on an empty stomach,” adds Maria Bushurova. “Hypercholesterolemia and diabetes are the most common causes of cardiovascular disease.”
- What it is. These are proteins that appear in the blood after the destruction of the fibers of the heart muscle. Normally, there are no troponins in the blood.
- How it works. Troponins are protein filaments that connect the heart muscle cells – cardiomyocytes. If cardiomyocytes are destroyed, troponins are released into the blood. These proteins are the earliest laboratory method for diagnosing the death of part of the heart muscle – the myocardium: the more cells that die, the higher the level of troponins.
- Why are they appointed. Troponin analysis is prescribed for suspected acute coronary syndrome – myocardial infarction. The study helps to distinguish the state of heart cells: they have already died – necrosis has occurred, or they simply do not have enough blood supply – a state of ischemia. Treatment tactics depend on this analysis.
“You can expect a rise in troponin levels as early as 3 hours after myocardial injury: from 2-12 hours according to various sources and depending on the test system used to determine the level of troponin,” says Maria Bushurova. – The peak concentration is after 12 hours and the increase persists up to 7-12 days. Usually, several tests are performed to evaluate the dynamics: for example, the rise of troponin over several hours.
- How to prepare. Special preparation is not needed. These tests are often performed under emergency conditions. If troponin is taken in the laboratory, it is recommended to exclude physical activity and smoking for 30 minutes before the procedure.
- What to look for when choosing a laboratory. Laboratories have different normal troponin ranges due to different reagents. You can not compare the results of two laboratories, focus on one.
- How to understand the results. The lower the level of troponins, the better, normally up to 1 μg / l. A slight increase in proteins can be with myocarditis, pericarditis – inflammation of the heart muscle or bag. If several tests were done with a time interval and the level of troponins increased, doctors suspect a myocardial infarction.
Creatine phosphokinase-MB (CPK-MB)
- What it is. Creatine phosphokinase is an enzyme. In the body, it exists in the form of fractions: MM, MB and BB. The MB fraction is found in the cells of the heart muscle.
- How it works. The enzyme helps provide energy to heart cells. If the cells are destroyed, CPK enters the blood, where it is quickly processed and excreted by the kidneys. On the third day after a heart attack, the level of CPK-MB returns to normal.
- Why are they appointed. The analysis is performed if myocardial infarction is suspected. With its help, a heart muscle infarction is distinguished from a lung infarction, an angina attack.
“According to a long tradition, in case of suspected acute coronary syndrome, the levels of intracellular components of myocytes continue to be assessed: CPK, CPK-MB,” notes the family doctor, cardiologist, nutritionist at GMS Clinic, Ph.D. Natalya Polenova . “However, highly sensitive troponins T and I are much more specific and sensitive markers of damage to myocardial muscle cells.”
It can be used to diagnose carbon monoxide poisoning and Reye’s syndrome – a violation of the liver and other internal organs in children.
- How to prepare. They donate blood on an empty stomach, the day before they exclude physical activity, half an hour before that – smoking. You do not need to go to the laboratory earlier than 6-8 hours after the onset of heart pain.
- How to understand the results. The norm of KFK-MB is up to 25 U / l. Limit values will depend on the sensitivity of the laboratory test system. The level of CPK-MB increases with myocardial infarction, alcohol or carbon monoxide poisoning, taking diuretics, statins, chemotherapy, hypothyroidism.