Mural Thrombus – Introduction, Causes, Diagnosis, Treatment

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Introduction

Mural thrombus is basically a blood clot that is formed in the blood and is attached to the lining of a chamber of the heart or the wall of a blood vessel. They are dangerous and can break loose to form emboli. A mural thrombus can be symptomatic or asymptomatic; they are mainly formed in the aorta. They can be diagnosed with imaging techniques such as CT scan, transesophageal echocardiography, and magnetic resonance imaging. Through these methods, the non-cardiac thrombi are found emerging in the patients with unexplained luminal occlusion. Mural thrombus is usually located in the abdominal aorta, but can also occur in the thoracic aorta. Usually, the occurrence is seen in older people because the thrombus arises from ulcerated atherosclerotic plaques. Several studies have also shown that younger people can also be affected by thrombus.

What is Mural Thrombus?

A thrombus is known as a blood clot, generally which is the coagulation of blood and attached to the wall of a blood vessel or to the lining of a chamber of the heart. The platelets and red blood cells in our body form a network of fibrin protein and it is a response of the body to injuries to prevent blood from flowing out. The clots formed help in stopping the blood from flowing out of the healthy blood vessels. Now, a mural thrombus is the thrombus linked to the wall of the blood vessel which can occur in large vessels like the aorta or the heart and prevent usual blood flow, partially. Such blood clots in the heart can increase the risk of strokes, pulmonary embolism, and heart attacks. The emboli that are formed from the clots that break free from the wall of the blood vessels can reach the right side of the heart and then the pulmonary artery, thus causing pulmonary embolism.

What Causes Mural Thrombus?

There can be a few causes that could lead to the formation of mural thrombus. These are:

Abnormal blood flow which can be caused due to various factors like hemostasis in the veins or disturbance in the arteries.
Hypercoagulation of blood which is found in patients suffering from leukemia, etc.
Injury caused to the endothelial cells which are present inside the blood vessels. Endothelial injury can be caused by conditions like trauma.
DIC (Disseminated intravascular coagulation) i.e. the formation of microthrombi throughout most of the blood vessels. This condition is caused by the consumption of coagulation factors in excess that leads to the activation of fibrinolysis that uses all the platelets and clotting factors present in the body. This condition can lead to hemorrhage. This condition can also be seen in pregnant women and people suffering from certain severe traumas.

Other common conditions that increase the risk of mural thrombus formation in a person’s body include heart valve replacement, recent heart attacks, inactivity for a long period of time, genetic deficiencies, atrial fibrillation, and more other disease-related factors that instigate the formation.

How to Diagnose Mural Thrombus?

The formation of thrombi on the lining of a chamber of the heart, also known as cardiac thrombi, can be detected through methods like echocardiography, where the intra-cardiac thrombi will appear as hyper-echoic filling defects that have no internal blood flow in them. This type of mural thrombus can also be detected via CT scan where they appear well-circumscribed and non-enhancing masses that are present adjacent to the endocardial surface. But, the most accurate diagnosis of mural thrombus formation can be made via MRI as similar features can be seen through MRI scanning, but the enhancement of the thrombi can be measured more accurately with MRI than any other method. The diagnosis depends upon a combination of the images collected from the body and their locations. When the case is uncertain, a trial of anticoagulation is followed by the imaging methods which can give a final result.

Diagnosis of mural thrombus formation is very important, especially when it is intra-cardiac thrombus formation which is most common in case of atrial fibrillation when the thrombus forms in the left atrium. It is important because under such cases the patients are at a high risk of pulmonary embolism and heart attacks. But, diagnosis can be difficult at times as the thrombus formation can be asymptomatic as well. Thrombus can also be confused with a tumor sometimes. Under such circumstances, intravenous injections of contrast agents can be useful because thrombi do not show any enhancement when intravenous injection of gadolinium is induced in the person.

With the advancement in technology and new methods of diagnostic tests, the thoracic aorta thrombi can also be diagnosed in patients, even in asymptomatic patients. It is one of the highest reported locations where mural thrombus formation has been reported to have occurred other than being found in cardiac areas. They can be detected with spiral CT scan, magnetic resonance imaging, and more such diagnostic tests.

Treatment of Mural Thrombus

Through different blood clots prevention methods and treatment procedures, the risks of the serious conditions that can affect a person due to mural thrombus formation like pulmonary embolism, stroke and heart attacks can be reduced. A drug known as streptokinase can be used intravenously which helps in dissolving the blood clots in the coronary vessels. The drug is basically an enzyme which is secreted by numerous streptococcal bacteria. The drug can be useful for dissolving abnormal blood clots, but it has the quality of digesting almost any protein present in the body which in turn can lead to other problems. Tissue plasminogen activator (tPA) is another drug used for dissolving the blood clots. It is made by transgenic bacteria which help in converting plasminogen in the clot-dissolving enzyme. Certain anticoagulants collected from animals are also useful for dissolving fibrin. Systematic anticoagulation therapy has been helpful in treating mural thrombus, especially when it is in the aorta. With this treatment, it has been possible to dissolve the blood clots, successfully.

The two types of treatment procedures for treating mural thrombus formation are a medical therapy which includes anticoagulation therapy and the other option being an intervention which includes surgery. Surgical methods are usually used for the patients who have failed to respond successfully to the anticoagulation therapy and other medical therapies. They are only applied on the patients after observing the patient and checking if he/she is fit for a surgery and is symptomatic. Thrombectomy is one of the options available under interventions.

Conclusion

Dissolution of the thrombus is very important for restoring good health and normal blood flow within the person’s body. Dissolution will occur once the fibrinolytic mechanisms can break the thrombus which will ultimately help in restoring blood flow through the vessels. This process can be done with the help of drugs like those mentioned above. Mural thrombus occurs mostly in association with various heart diseases which can lead to more severe health issues. When the mural thrombus is not associated with any heart disease, it generally occurs in the right atrium. It is necessary to inspect the myocardium to make the required diagnosis for mural thrombus. The location of the thrombi formation is also very important for suggesting the required treatment options to the patient. With proper diagnosis and treatment, the patient can reduce the risks of getting affected by severe life-threatening diseases. Proper exercises and a healthy diet along with other preventive measures can also help to reduce the chances of mural thrombus formation.

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