Thoracic aortic aneurysm
Introduction
Introduction to thoracic aortic aneurys Thoracic aortic aneurysms can occur in the ascending segment of the aorta, any part of the arch and descending segments, especially the bow and descending segments. Sometimes the entire aorta expands, and localized aneurysms occur in multiple locations in the thoracic aorta and abdominal aorta. The descending aortic aneurysm often extends to the abdominal aorta to form a thoracic and abdominal aortic aneurysm. The most common cause is atherosclerosis, followed by aortic cystic necrosis, syphilis, infection, injury, and congenital hypoplasia. basic knowledge The proportion of illness: the incidence rate is about 0.0001% - 0.0003% Susceptible people: the elderly Mode of infection: non-infectious Complications: congestive heart failure
Cause
Cause of thoracic aortic aneurysm
(1) Causes of the disease
The most common causes of thoracic aortic aneurysm are: atherosclerosis, non-specific aortic degeneration, followed by aortic cystic necrosis, syphilis, infection, injury, and congenital dysplasia.
1. The most common cause of thoracic aortic aneurysm formation in atherosclerotic atherosclerosis and non-specific aortic degenerative diseases, accounting for more than 50%.
2. Aortic cystic necrosis Aortic cystic necrotic thoracic aortic aneurysm often combined with Marfan syndrome, showing obvious genetic characteristics.
3. Traumatic factors are more common in traffic accidents. They suddenly decelerate during high-speed exercise, causing the aortic intima and middle layer to rupture horizontally. If the ascending aorta is broken or completely broken, the patient will soon die from bleeding and will not be rescued.
4. Infectious factors Infectious embolus of infective endocarditis obstructs the nutritional vessels in the aortic wall, infections adjacent to the aorta, such as abscesses, suppurative lymphadenitis and empyema, etc., or trauma, surgery Due to the spread of sepsis, the number of patients infected with syphilis has increased in the past 10 years.
(two) pathogenesis
The middle cystic degeneration of the thoracic aorta is the most important cause of thoracic aortic aneurysm. It can represent smooth muscle cell necrosis, elastic fiber degeneration and mucin-like deposition in the middle aorta. This pathological change mostly occurs in the ascending aorta, a few Can be seen in the descending aorta. The aortic wall can be thinned and twisted to form a fusiform aneurysm. If it occurs in the aortic root, it can cause aortic regurgitation. All patients with Marfan syndrome can see cystic changes in the aortic wall. It can also be found in other hereditary connective tissue diseases, such as Ehlers-Danlos syndrome.
Aortic aneurysm rarely develops atherosclerosis, but can be associated with extensive atherosclerosis, especially the renal artery, cerebral arteries and coronary arteries. Aneurysms in the aortic arch often involve the ascending aorta or descending aorta, often Due to middle cystic degeneration, atherosclerosis, syphilis or other infections, thoracic aortic aneurysms often have hypertension, which can affect the strength of the aortic wall and accelerate the expansion of the aneurysm in the chest, limitations Cystic aneurysms are more common than annular or diffuse aneurysms.
Prevention
Thoracic aortic aneurysm prevention
1. Because atherosclerosis and non-specific aortic degeneration are the main causes of aneurysm formation, it is necessary to prevent and actively treat atherosclerosis.
2. Once the aortic aneurysm is diagnosed, the diameter of more than 5cm, with or without symptoms, should be treated early, remove the aneurysm, transplant the artificial blood vessels, and restore normal blood supply.
Complication
Thoracic aortic aneurysm complications Complications, congestive heart failure, sudden death
Thoracic aortic aneurysm can cause congestive heart failure, myocardial ischemia or myocardial necrosis; when the aneurysm thrombosis can cause embolism (cerebral embolism, limb embolism, etc.); the most severe thoracic aortic aneurysm rupture can cause severe pain, sudden death Wait.
Symptom
Common symptoms of thoracic aortic aneurysm Right heart failure dysphagia, shortness of breath, heart failure, tracheal translocation, ureteral centripetal deviation
40% of patients with thoracic aortic aneurysm are asymptomatic, and typical aneurysm changes are found during routine physical examination or chest X-ray. The symptoms and signs of an aneurysm are related to their size and location, and mainly due to its Invasion or compression of adjacent structures, vascular involvement, if the aortic root is dilated, secondary aortic regurgitation with congestive heart failure; if Valsalva sinus tumor involves the coronary artery, it can cause myocardial ischemia or myocardial ischemia Necrosis. When the Valsalva sinus tumor breaks into the right heart, there may be continuous murmur or right heart failure; if the aneurysm thrombosis and shedding can cause cerebral infarction, limb necrosis, renal infarction or intestinal necrosis; thoracic aortic aneurysm compression upper cavity Facial, neck and shoulder venous engorgement with edema, coughing and shortness of breath when compressing the trachea and bronchus, dysphagia caused by compression of the esophagus, squeaking caused by compression of the recurrent laryngeal nerve; chest aortic aneurysm often causes pain, sudden pain Aggravation of the possibility of rupture; ascending aortic aneurysm can erode the sternum and costal cartilage and protrude from the anterior chest, showing a pulsatile mass; the thoracic aortic aneurysm breaks into the bronchus, trachea, chest or Package can lead to death.
Examine
Examination of thoracic aortic aneurysm
1. Blood routine Most patients with blood routine examination in the normal range, such as combined with dissection aneurysm, mild anemia can occur in the acute phase, white blood cell count increased within a few hours of onset, greater than 10 × 109 / L, infectious aortic aneurysm, White blood cell counts increase and neutrophils increase.
2. Most of the urine routine is in the normal range. For example, with a dissection aneurysm, urine protein may be positive in the urine, tube type and a large number of red blood cells.
3. Patients with dyslipidemia and atherosclerosis often show elevated blood lipids and blood viscosity.
4. Chest X-rays Many thoracic aortic aneurysms can be directly observed from the chest radiograph, which is characterized by widening of the mediastinum, aortic enlargement, and tracheal deviation, but small aneurysms, especially cystic aneurysms, are difficult. It was found from the chest radiograph that the abdominal aorta was significantly widened from the abdominal plain (posterior anterior, oblique and lateral). If the tumor wall had calcification, the abdominal aortic aneurysm was visible.
5. Aortic angiography This technique is an excellent way to determine the extent of aortic aneurysm and its anatomical location with large vessels, but the disadvantage of aortic angiography is that it is expensive and potentially dangerous.
6. Computed tomography (CT) and magnetic resonance imaging (MRI) are the most accurate and useful methods for localization and measurement of aortic aneurysms, and MRI has a clearer relationship with the features, contours, and surrounding structures of the tumor cavity. Other organs also provide useful information. MRI technology can construct three-dimensional images, so the anatomical relationship around the aorta can be observed from a series of projection positions, but the image time is long and expensive.
7. Echocardiography Echocardiography is the most valuable method for screening thoracic aortic aneurysms. Ultrasound can detect tumors from cross-section and slitting. The sensitivity is close to 100%. The main advantage is that it is inexpensive, non-invasive, and does not require imaging. Agent.
8. Esophageal echocardiography Esophageal echocardiogram (TEE) is a very accurate method for evaluating thoracic aortic aneurysm and has been widely used in the diagnosis of aortic dissection.
Diagnosis
Diagnosis and diagnosis of thoracic aortic aneurys
Diagnostic criteria
Most thoracic aortic aneurysms can be found on the chest X-ray, which is characterized by a widening of the mediastinum, aortic node enlargement or tracheal displacement. However, some aneurysms are small, especially cystic aneurysms, which are not found on the chest radiograph. It has been ruptured, at this time, X-ray films can not rule out the diagnosis of aneurysms.
Arteriography is still a good method for preoperative evaluation and accurate determination of the anatomic structure and size of aneurysms when surgical treatment of thoracic aortic aneurysm is selected. Enhanced CT scan with contrast agent can determine and measure the ascending aorta and descending aorta. Aneurysm.
Transthoracic echocardiography is less accurate than CT scan in the diagnosis of thoracic aortic aneurysms, especially thoracic descending aortic aneurysms. Transesophageal echocardiography (TEE) is used to observe ascending aortic aneurysm and descending aortic aneurysm. The image is clear and reliable. High compliance rate.
MRI is used to determine the anatomy of the ascending aorta and ascending aortic aneurysms, which is more reliable than CT scans and can detect the original arterial lesions of the patient.
Differential diagnosis
1. Aortic dissection aneurysms are mostly caused by the separation of aortic intima on the basis of thoracic aortic aneurysm. The two are similar and difficult to identify, but the dissection aneurysms often have a sudden history, severe chest pain at the onset. The tearing or knife cutting, often accompanied by shock symptoms, if not diagnosed and treated in time, the disease progressed rapidly and died.
2. Thoracic aortic pseudoaneurysm This disease can occur in the ascending aorta, aortic arch and descending aorta, but pseudoaneurysm often has a history of trauma or infection, echocardiography, CT and MRI can provide identification, necessary Angiography is performed.
3. Central lung cancer is sometimes difficult to distinguish from thoracic aortic aneurysm, but the disease has cough, cough with blood history, tumor cell examination is positive, fiber beam bronchoscopy, pathological specimen examination can confirm the diagnosis.
4. Lower esophageal cancer and descending aortic aneurysm in esophageal cancer are easily confused when X-ray examination, but esophageal cancer has a history of progressive dysphagia. Esophageal barium meal and esophagoscopy can confirm the diagnosis.
