There coronary angiography (CNG) is an exam used for the study of coronary arteries, ie the arteries which feed on oxygenated blood cardiac muscle, In case of coronary artery obstruction, the heart can meet ischemia myocardial, which is manifested by the signs and symptoms of angina pectoris - pain in the chest, located under the left breast or behind the breastbone, often radiating to the left arm and shoulder - or actual heart attack, in which in addition to the symptoms described above, an alteration of the cardiac enzymes is added (troponin T and I, myoglobin, creatinkinase). Coronary angiography also allows for the treatment of changes atherosclerotic coronary, via angioplasty - the enlargement of the constricted vessels - and lo stenting - placement of stents, small tubes that keep the coronary artery open even at a distance from the procedure.
What are heart and coronaries? The heart is a fundamental organ of the human body: it is one muscle pump located in the chest that contracts rhythmically and constantly to ensure adequate Blood flow to the lungs and the rest of the body. Much of the heart is made up of myocardium, particular type of muscle which contracts automatically and rhythmically when it receives a sufficient supply of oxygen and nutrients.
Inside the heart there are four distinct cavities: the two upper ones are the lobbies, the lower ones i ventricles. A thick muscular wall divides the right half (intended to receive the deoxygenated blood) from the left, which sends oxygen-rich blood flow from the lungs to all parts of the body.
For this reason we speak of the heart as a dual-function pump, since the two halves of the organ have distinct but interdependent functions. Veins and arteries that enter the heart are called coronary and have the function of securing the heart coronary circulation: in fact the myocardium is a particularly thick muscle, therefore it needs a dense vascular network, which penetrates deeply. Consequently, it is essential to check that it is in perfect condition and that there are no obstructions or narrowings that restrict blood flow.
What is coronary angiography and how is it done
Coronary angiography (CNG) is a radiological technique for observing the veins and arteries that enter the heart. This system is also called coronary angiography and is based on the introduction into the blood vessels of an iodinated contrast medium, in most cases a radiopaque substance, that is, an iodized compound subsequently subjected to X-rays.
This test is performed for several reasons, in particular to detect diseases that alter the characteristics and volume of blood vessels. For example, coronary angiography allows to identify an obstruction of a vessel or its narrowing related to the formation of an atheroma, a thrombus or an embolus. In other cases it allows for aneurysms which weaken the wall of veins and arteries entering the heart.
Performing a coronary angiography also allows you to identify alterations in the texture of the vessels that carry blood to the heart muscle, while in still other circumstances the diagnostic test allows you to determine a coronary artery infection: in most cases, however, this test is prescribed in the suspicion of a ischemic heart disease or for diagnosis and therapy in the presence of an existing or recent myocardial infarction.
This examination allows to observe any anomalies in the caridid blood vessels, by injecting the contrast medium through a thin catheter, formed by a flexible plastic tube. Coronary angiography is divided into various types depending on the blood vessel in which the catheter is inserted: in fact, it is possible to operate on thefemoral artery at the groin, on the carotid vessels that run into the neck or on the brachial artery just above the elbow.
Consequently one speaks of femoral coronary angiography, caroditea or radial. Before performing this operation, a local anesthetic must be injected to numb the skin and tissues surrounding the area where the catheter is inserted. A needle will then be inserted into the artery percutaneous route and, through this guide, a long thin metal wire, hollow inside and with a rounded tip. It will then be possible to gently push the catheter into the blood vessel to be examined, the coronary arteries.
Subsequently, the doctor will inject the contrast medium into the artery thanks to the catheter and then carry out a rapid sequence of radiological images or a film that in real time allows you to see the blood vessels that become opaque - fill - with contrast medium. This procedure allows to monitor the disposition, the conformation and the possible anomalies of the blood vessels, in order to study the circulation both in the main artery and in its branches, and in the heart cavities.
What are the types of coronary angiography?
There are different types of coronary angiography that can be performed based on the diagnostic test to be performed and the patient's clinical condition. For example, carotid angiography can be performed if the subject suffers from transient ischemic attacks that at the same time present stroke symptoms that last less than 24 hours. In this way it is possible to verify the presence of an occlusion or a more or less severe narrowing of one of the carotid arteries, a factor that can limit the blood supply to the brain. This type of examination is often done in conjunction with a cardiac catheterization so that the location of the obstruction or narrowing of blood vessels can be identified. In this way, a coronary bypass or balloon angioplasty can be done to solve the problem. Depending on the point of the body in which the catheter is introduced, the term to indicate the technique used changes. For example, we talk about femoral coronary angiography if the catheter is introduced through an access created in the femoral artery and then positioned at the inguinal level. Instead, radial coronary angiography is the technique that allows you to reach the aortic valve through the radial artery located in the arm at the elbow. There is a type of non-invasive coronary angiography called digital subtractive angiography: it is a solution that uses computerized techniques to process images, so as to have a sharper definition. At the same time, this technique allows you to subtract or eliminate unwanted background information: in this way the resulting images only concern blood vessels that the doctor has to study. This type of radiological system is more advantageous than the other solutions because it allows the use of a decidedly smaller quantity of contrast medium and the injection can be carried out intravenously. The non-invasive technique is also defined with the name coronary CT or coronary angio-CT: to view and scan the coronary arteries, so as to be able to diagnose various heart diseases and identify the possible presence of atherosclerotic plaques, a computed tomography is performed. Also in this case a contrast agent is used, however there are some peculiarities that allow to distinguish this examination from the classic technique. First of all, the subject subjected to the examination must be fasting (while in the case of CNG bsiogna not having taken food and liquids in the previous 8 hours) and the procedure takes place in apnea: for this reason it lasts a few seconds. The computer then processes the images and scans of the coronary arteries that are used by the cardiologist and radiologist to draw up the medical report.
What do angioplasty and stents mean?
Sometimes angiography of the chambers of the heart is prescribed in conjunction with coronary angiography of the coronary arteries through a catheter. It is also possible to measure intracavitary pressures, so as to verify the value of intravascular pressures and the presence of pathologies affecting the valve flaps, for example heart failure or stenosis. Angiography allows you to measure the size of the veins and arteries that enter the heart, the atria and ventricles of the heart muscle. At the same time, the general and segmental functionality of the ventricles themselves is verified. Following the results of coronary angiography, it is possible to develop a cardiac angioplasty procedure or use a stent to resolve the occlusions of the blood vessels. In the first case, in most cases, we have to do with an atheroma-physical plaque, which in turn causes the lumen to narrow, a problem defined in medical terms as stenosis. To dilate the blood vessel, a particular type of balloon catheter is introduced through a percutaneous puncture in the presence of an artery. The latter is made to rise until it reaches the stenotic vessel and inflated precisely where the narrowing occurred: in this way the blood vessel returns to its normal diameter and, consequently, the circulatory flow is restored correctly. Even the adoption of the stent allows to eliminate or considerably reduce the stenosis of the blood vessels, but also allows to exclude the presence of an aneurysm. This name indicates a special cylindrical metal mesh structure to be introduced into blood vessels or lumen organs (characterized by being hollow or viscera). Once correctly positioned, the stent is made to expand until it reaches the same diameter as the blood vessel. Subsequently it is recommended to administer an aspirinette. Patients at risk of thrombosis, on the other hand, can undergo a treatment based on antiplatelet drugs.
Risks of coronary angiography
Coronary angiography generally does not present great risks because it is a very safe diagnostic tool. Usually the contrast medium used to carry out the examination produces only a sensation of heat that lasts for a few seconds: often at the point where the injection is performed the effects are more perceptible. The most serious side effect that can occur is an allergic reaction caused by the contrast agent used. However, thanks to the recently developed contrast media, the risk of a serious reaction following a coronary angiography is less than 1 in 80,000 tests. Other risks that may affect people who undergo this test are a lesion of the blood vessels or a rupture of the coronary arteries. This problem can occur at both the puncture site and the contrast injection site and anywhere in the blood vessel while the catheter is being inserted. If digital subtractive angiography is performed, the risks of damage to blood vessels are lower because the catheter is inserted superficially. Furthermore, this diagnostic technique is contraindicated for those who are allergic to iodized solutions or for patients who are undergoing insulin treatment as they suffer from renal insufficiency. For this reason, the doctor, before prescribing coronary angiography, must carefully examine the subject's health conditions and clinical history. At the same time, this procedure cannot be performed on pregnant women because the use of X-rays could have side effects or harm the health of the fetus. Furthermore, CNG is not very suitable for people suffering from obesity.
Duration of the examination and average hospital stay required
Depending on the motivation behind the examination, coronary angiography can have a very variable duration. In fact, in some cases a few minutes are enough, while in others it takes 2-3 hours to be able to monitor the entire network of blood vessels or a part. Depending on the duration of the examination, the period of time in which the patient remains under observation after undergoing coronary angiography also varies. Generally a few hours must pass, which in some cases can be 5-6. Once doctors are sure that the person is not experiencing complications of various kinds and that they are in good health, they can sign the discharge form from hospital. The hospitalization period, however, also continues at home as the patient must remain at rest for at least the next 24 hours.Tags: Cardiology Blood vessels