Introduction
Thoracic Aortic Aneurysm(TAA)
A thoracic aortic aneurysm is a weakened area in the major blood vessel that feeds blood to the body (aorta). When the aorta is weak, blood pushing against the vessel wall can cause it to bulge like a balloon (aneurysm).
A thoracic aortic aneurysm is also called a thoracic aneurysm, and aortic dissection can occur because of an aneurysm. A dissection is a tear in the wall of the aorta that can cause life-threatening bleeding or sudden death. Large, fast-growing aneurysms also may rupture, but small and slow-growing aneurysms may never rupture.
Depending on the cause, size and growth rate of thoracic aortic aneurysm, treatment may vary from watchful waiting to emergency surgery. Ideally, surgery can be planned if necessary.
Aortic Dissection
An aortic dissection is a serious condition in which the inner layer of the aorta, the large blood vessel branching off the heart, tears. Blood surges through the tear, causing the inner and middle layers of the aorta to separate (dissect). If the blood-filled channel ruptures through the outside aortic wall, aortic dissection is often fatal.
Aortic dissection is relatively uncommon. The condition most frequently occurs in men in their 60s and 70s. Symptoms of aortic dissection may mimic those of other diseases, often leading to delays in diagnosis. However, when an aortic dissection is detected early and treated promptly, the chance of survival greatly improves.
Symptoms
Aneurysm-related symptoms
(1) Heart: When the aneurysm compresses the heart, the manifestations can be aortic insufficiency, superior vena cava syndrome, and venous distention in the face/shoulder/neck.
(2) Respiratory system: Compression of the trachea and bronchi can cause cough, shortness of breath, and atelectasis.
(3) Digestive system: Compression of the esophagus can cause dysphagia.
(4) Nervous system: Compression of the recurrent laryngeal nerve can cause hoarseness, while compression of the sympathetic nerve can cause Horner syndrome.
(5) Other symptoms: The slow blood flow and eddy current in the aneurysm wall can cause thrombosis in the aneurysm cavity, while the detachment of the mural thrombus can cause arterial embolism in the brain, internal organs, and extremities.
Dissection-related symptoms
(1) Pain: Acute aortic dissection starts suddenly, and it is manifested in more than 90% of patients as sudden and severe tearing pain or cutting pain in the anterior chest, back or abdomen, and the pain can be transmitted and transferred to the abdomen or lower abdomen along the direction of the aorta.
(2) Sudden death: When the ascending aorta ruptures, blood will flow into the pericardial cavity and cause acute cardiac tamponade, further resulting in sudden death.
(3) Nervous system symptoms: When involving the brachiocephalic trunk, the dissection will cause cerebral blood supply disorder, and represents syncope, coma, and hemiplegia.
(4) Abdominal pain: When involving the solid organs in the abdominal cavity, the dissection will cause abdominal pain.
(5) Lower extremity ischemia: Manifested as “5P” (Pain, Pallor, Paralysis, Pulselessness and Paresthesia).
Diagnosis
Ultrasound Doppler
CT
Computer Tomography
MRA
Magnetic resonance angiography
DSA
Digital Subtraction Angioplasty
It can detect the aortic aneurysm above 3 cm in diameter, show the aneurysm size, and identify the plaque and thrombus.
Plain scan and enhanced scan can accurately reveal the shape of the aneurysm and its adjacent relationship with the surrounding organs, so that doctors can determine whether there is an anatomical abnormality and find out whether there are other concomitant intra-abdominal diseases. Three-dimensional computed tomographic angiography (3DCTA) can demonstrate the three-dimensional morphological characteristics and size of the aneurysm, as well as the affected abdominal aorta branches more accurately. It can also accurately measure the parameters of each part of the aneurysm.
MRA can show the location, size, and shape of the lesion clearly without any contrast agent, and can provide a vivid image. It has high diagnostic value for the subacute or chronic hematoma caused by aneurysm rupture.
It is of great value for the diagnosis of thoracoabdominal aortic aneurysm, multiple aneurysms and aortic dissection. It cannot provide the real image of the aneurysm cavity, when there is a large amount of mural thrombus in the aneurysm cavity.
Treatment
Open-chest Surgery
Introduction to Surgery
The surgery is designed to replace the diseased thoracic aortic segment with artificial blood vessel. The surgery method and postoperative curative effect vary with the anatomical part of the thoracic aorta. During the procedure, some technical support may be needed as well, such as cardiopulmonary bypass, deep hypothermia circulatory arrest or selective cerebral perfusion. The surgical mortality rate is about 5% to 10%. Surgery complications may include bleeding, severe arrhythmia, insufficient coronary blood supply and complications of central nervous system. The 1-year survival rate after surgery is 80% to 90%, and the 5-year survival rate is 60% to 80%.
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Thoracic Endovascular Aortic Repair(TEVAR)
Introduction to Surgery
TEVAR refers to an approach that involves placing a stent-graft in the thoracic aortic lumen to isolate the thoracic aortic aneurysm cavity, without thoracotomy and cardiopulmonary bypass. This approach has the advantages of little trauma, fast recovery, few complications and contraindications. The development of endovascular devices, including the single-branched stent graft (Castor), makes the endovascular repair also available for some thoracic aortic aneurysms involving the branch artery on the aortic arch.
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