An aortic mural thrombus is a blood clot that forms on the inner wall of the aorta, the largest artery in the human body. Unlike clots that completely block a vessel, a mural thrombus adheres to the vessel wall. This condition can lead to serious health issues if parts of the clot break away and travel through the bloodstream.
Understanding Aortic Mural Thrombus
The aorta is a large, cane-shaped artery that originates from the lower-left chamber of the heart, known as the left ventricle. It extends upwards, curves over the heart, and then descends through the chest and abdominal cavities before splitting into smaller arteries in the pelvis. The aorta’s primary role is to deliver oxygen-rich blood, nutrients, and hormones from the heart to all parts of the body, with smaller vessels branching off to supply various organs, muscles, and tissues.
Aortic mural thrombi are typically found in the descending aorta, which runs through the chest, though they can also occur in the aortic arch or the abdominal aorta. While attached to the vessel wall, they may not immediately cause symptoms at their site of origin, but their presence can still be a concern.
Causes and Risk Factors
Atherosclerosis, a condition where plaque builds up and hardens on the inner walls of arteries, is a common underlying cause. This plaque can create an uneven surface that promotes clot formation.
Aortic aneurysms, which are weakened, bulging areas in the aortic wall, also increase the risk. These dilated sections can lead to turbulent blood flow, allowing blood to pool and clot. Aortic dissection, a tear in the aortic wall that allows blood to flow between its layers, can also contribute to thrombus formation. Less commonly, hypercoagulable states—conditions that make blood more prone to clotting—can lead to mural thrombi.
Symptoms and Complications
Aortic mural thrombi are often asymptomatic. The most serious issues occur when a portion of the thrombus detaches from the aortic wall and travels through the bloodstream, a process known as embolization. These emboli can then block blood flow in smaller arteries elsewhere in the body.
If an embolus travels to the brain, it can cause a stroke, leading to symptoms like sudden weakness or numbness on one side of the body, difficulty speaking, or vision problems. When emboli block blood flow to an arm or leg, it can result in limb ischemia, characterized by pain, numbness, coolness, or weakness in the affected limb. Embolization can also lead to organ damage if the clot obstructs blood flow to organs such as the kidneys, intestines, or even the heart itself, causing kidney damage, mesenteric ischemia, or myocardial infarction. Complications from embolization can be severe and require immediate medical attention.
Diagnosis and Treatment Approaches
Diagnosing an aortic mural thrombus involves imaging techniques to visualize the aorta and detect clots. Computed Tomography (CT) scans are frequently used and can show aortic thrombi. Magnetic Resonance Imaging (MRI) is also used for detecting thrombi throughout the thoracic aorta. Transesophageal echocardiography (TEE), where a probe is guided down the esophagus to get a closer look at the heart and aorta, can also confirm the presence of a floating thrombus.
Treatment strategies often begin with anticoagulation therapy, using blood thinners to prevent further clot growth and reduce the risk of embolization. In some cases, especially when the thrombus is mobile, causing recurrent embolisms, or when anticoagulation is not suitable, surgical intervention may be considered. Surgical options include thrombectomy (removal of the clot) or repair of an underlying aneurysm. Endovascular procedures, which involve less invasive techniques to address the thrombus, are also used.