Thoracic aortic dissecting aneurysm
Introduction
Introduction to thoracic aortic dissection Aortic blood flow through the intimal rupture into the aortic wall, forming a hematoma in the aortic wall. When the hematoma is enlarged, the middle layer of the aortic wall is peeled off into two layers, the inner and outer layers, which are called aortic dissection aneurysms. Sennertus in 1542, the disease was described in Morgagni in 1761. 1826 Thoracic aortic dissection aneurysm is the aortic blood flow through the intimal rupture into the aortic wall, forming a hematoma in the aortic wall, when the hematoma expands, the middle layer of the aortic wall is stripped into two layers, the inner and outer layers, called the main Arterial dissection aneurysm. The incidence of aortic dissection aneurysms is 5 to 10 per million population per year. The ratio of male to female is 3:1, and the age of onset is mostly over 40 years old. basic knowledge The proportion of illness: 0.0005% Susceptible people: no specific population Mode of infection: non-infectious Complications: myocardial infarction, sudden death, digestive tract bleeding, coma
Cause
Causes of thoracic aortic dissection
First, the cause
There are many reasons for the formation of aortic dissection, arteriosclerosis, hypertension, cystic necrosis of the arteries, Marfan syndrome, aortic coarctation, aortitis, trauma and syphilis, except for the injury, the pathological basis is the main Changes in the middle layer of arteries and smooth muscles.
Second, pathological changes
Degenerative lesions in the aortic wall, the adhesion of each layer of tissue is reduced, the aortic wall is affected by blood flow or the vasotrophic tube is broken, resulting in intimal rupture. The middle layer of the aortic wall is peeled off to form a thin outer layer and a thick inner wall. Interstitial hematoma, the stress generated by the heart beat has the greatest influence on the ascending aorta and the proximal descending aorta, so 60 to 70% of cases of dissection aneurysms originate from the ascending aorta, 25% originate from the proximal descending aorta, about 90% The case has hypertension. After the formation of the dissection aneurysm, it can extend to the distal aorta, involving the full length of the thoracic aorta and the abdominal aorta and its branches; the extension to the proximal aorta involves the coronary artery and the aortic valve. Catheter circulation blood flow blockage or aortic valve insufficiency, cerebral ischemic symptoms caused by dissection of the common carotid artery; intercostal artery involvement can lead to paraplegia caused by spinal cord ischemia; renal artery involvement leads to renal failure; If the femoral artery is involved, it can cause limb necrosis. If the dissection aneurysm grows into the pericardial cavity or pleural cavity, the pericardial tamponade or massive hemothorax can cause death. Some patients have aneurysms. Aortic lumen into the perforation layer, the aortic blood flow passageway formed two, aortic stripping process is no longer develop, the condition was alleviated.
Classification: In 1965, DeBakey was divided into three types according to the location and extent of dissection aneurysms, which were widely used in clinical practice.
Dissection aneurysm DeBakey classification
Type I: The rupture of the intima is located in the ascending aorta. The aortic wall dissection originates from the ascending aorta, involving the aortic arch, descending the aorta, and extending to the abdominal aorta.
Type II: The rupture of the intima is located in the ascending aorta, and the aortic wall is stripped to the ascending aorta.
Type III: The proximal rupture of the intima is located in the proximal descending aorta at the distal end of the left subclavian artery. The aortic wall is stripped toward the descending aorta and extends to the abdominal aorta, but does not involve the ascending aortic wall.
Stanford classification is divided into two types according to whether the ascending aorta is involved or not.
Type A: The rupture of the intima can be located in the ascending aorta, the aortic arch or the proximal descending aorta. The extent of the dissection aneurysm involves the ascending aorta, or even the aortic arch, descending aorta and abdominal aorta. The Stanforda type is equivalent to the DeBakey type. Type I and type II, type A accounted for approximately 66% of the number of cases.
Type B: The endometrial rupture is often located in the proximal descending aorta. The extent of the dissection aneurysm is limited to the descending aorta or extending into the abdominal aorta, but does not involve the ascending aorta, which is equivalent to DeBakey type III, and type B accounts for approximately 33%. .
Prevention
Thoracic aortic dissection aneurysm prevention
There is no effective preventive measure for this disease. Early diagnosis and early treatment is the key to the prevention and treatment of this disease. For patients undergoing surgery, the operative mortality rate of this disease is still high, and the lesions involve cases of ascending aorta. The operative mortality rate is 20-40%. The lesion is limited to the descending aorta. The operative mortality rate is 25-60%. The 5-year survival rate is about 50%. After 10 years, the 20-year survival rate is reduced to 30% and 5%.
Complication
Complications of thoracic aortic dissection Complications, myocardial infarction, sudden death, gastrointestinal bleeding, coma
When DeBekay I, type II dissection is involved in the aortic valve, diastolic or systolic murmurs in the aortic valve area occur. Aortic valve regurgitation is prone to acute left heart failure, rapid heart rate, difficulty breathing, etc. Exfoliation involving the coronary arteries can cause acute myocardial ischemia or myocardial infarction. When the dissection is broken into the pericardium, the pericardial tamponade can occur rapidly, resulting in sudden death. After several hours of onset, peripheral arterial occlusion can occur, and carotid or limb arterial pulsation can occur. Strong and weak, severe cases can occur limb ischemic necrosis, the dissection of the aortic arch of the brachiocephalic artery, can cause insufficient blood supply to the brain, and even coma, hemiplegia, etc., the dissection of the descending aorta involving the intercostal artery can affect the spinal cord blood supply caused by paraplegia Involved in the branches of the abdominal organs can cause liver blood supply deficiency, liver function damage, acute abdomen manifestations or gastrointestinal bleeding, renal function damage and renal hypertension.
Symptom
Symptoms of thoracic aortic dissection aneurysm Common symptoms Chest pain severe pain vascular murmur Heart murmur purpura skin pale pericardial tamponade sustained chest pain...
First, clinical manifestations
In most patients, the dissection of the aortic aneurysm suddenly appears in the abdomen, chest or back knife cut or tear-like severe pain, chest pain can be radiated to the neck, arms, similar to acute myocardial infarction, the administration of morphine drugs failed Pain relief, pain is persistent, until the dissection of the dissection aneurysm is self-relieving, patients often show pale skin, sweating, peripheral purpura and other signs of shock, but blood pressure is still higher than normal, abdominal pain is easy to with acute abdomen Confusion, but cases of dissecting aneurysms rarely show nausea, vomiting, abdominal tenderness and abdominal muscle tension, aortic wall stripping lesions involving the ascending aorta can present a diastolic heart murmur of aortic regurgitation, involving the subclavian artery, neck Local arterial and iliac femoral arteries may have local vascular murmurs, ipsilateral pulse and blood pressure weakened or disappeared, and lesions involving cerebral vessels may be confused with cerebral hemorrhage or cerebral thrombosis caused by hypertension, and intercostal artery involvement may suddenly appear paraplegia. .
Second, pathological changes
Degenerative lesions in the aortic wall, the adhesion of each layer of tissue is reduced, the aortic wall is affected by blood flow or the vasotrophic tube is broken, resulting in intimal rupture. The middle layer of the aortic wall is peeled off to form a thin outer layer and a thick inner wall. Interstitial hematoma, the stress generated by the heart beat has the greatest influence on the ascending aorta and the proximal descending aorta, so 60 to 70% of cases of dissection aneurysms originate from the ascending aorta, 25% originate from the proximal descending aorta, about 90% The case has hypertension. After the formation of the dissection aneurysm, it can extend to the distal aorta, involving the full length of the thoracic aorta and the abdominal aorta and its branches; the extension to the proximal aorta involves the coronary artery and the aortic valve. Catheter circulation blood flow blockage or aortic valve insufficiency, cerebral ischemic symptoms caused by dissection of the common carotid artery; intercostal artery involvement can lead to paraplegia caused by spinal cord ischemia; renal artery involvement leads to renal failure; If the femoral artery is involved, it can cause limb necrosis. If the dissection aneurysm grows into the pericardial cavity or pleural cavity, the pericardial tamponade or massive hemothorax can cause death. Some patients have aneurysms. Aortic lumen into the perforation layer, the aortic blood flow passageway formed two, aortic stripping process is no longer develop, the condition was alleviated.
Classification: In 1965, DeBakey was divided into three types according to the location and extent of dissection aneurysms, which were widely used in clinical practice.
Dissection aneurysm DeBakey classification
Type I: The rupture of the intima is located in the ascending aorta. The aortic wall dissection originates from the ascending aorta, involving the aortic arch, descending the aorta, and extending to the abdominal aorta.
Type II: The rupture of the intima is located in the ascending aorta, and the aortic wall is stripped to the ascending aorta.
Type III: The proximal rupture of the intima is located in the proximal descending aorta at the distal end of the left subclavian artery. The aortic wall is stripped toward the descending aorta and extends to the abdominal aorta, but does not involve the ascending aortic wall.
Stanford classification is divided into two types according to whether the ascending aorta is involved or not.
Type A: The rupture of the intima can be located in the ascending aorta, the aortic arch or the proximal descending aorta. The extent of the dissection aneurysm involves the ascending aorta, or even the aortic arch, descending aorta and abdominal aorta. The Stanforda type is equivalent to the DeBakey type. Type I and type II, type A accounted for approximately 66% of the number of cases.
Type B: The endometrial rupture is often located in the proximal descending aorta. The extent of the dissection aneurysm is limited to the descending aorta or extending into the abdominal aorta, but does not involve the ascending aorta, which is equivalent to DeBakey type III, and type B accounts for approximately 33%. .
Examine
Examination of thoracic aortic dissection
First, ECG examination
Electrocardiogram examination generally has no abnormal signs, which can rule out the diagnosis of myocardial infarction, and cases with hypertension can show left ventricular hypertrophy.
Second, chest X-ray examination
Chest X-ray examination is a simple and reliable diagnostic method. In cases of dissecting aortic aneurysm involving the ascending aorta, the mediastinal shadow is widened to the right on the chest X-ray film, and the left aorta is widened to the left. The aortic arch showed a localized bulge, and the outer diameter of the ascending aorta and the descending aorta was disparate. The ascending aorta and aortic arch were enlarged, deformed, and the aortic wall was thickened. The distance between the intimal calcification plaque and the outer edge of the aorta was widened, and the interval was repeated for half an hour. The radiograph showed changes in the shape of the thoracic aorta and mediastinum, sometimes the aorta showed double-chamber shadows, and some cases showed pleural effusion.
Third, aortic angiography
Chest X-ray examination showed that the above abnormalities should be immediately performed by aortic angiography, and it is required to fully display the total length of the aorta (from the aortic valve to the bifurcation of the abdominal aorta). Aortic angiography can show the blood flow formed by the aortic wall exfoliation. The abnormal channel compresses the aortic cavity, understands the length of the aortic wall stripping segment, the location of the intimal rupture, the anatomy and function of the aortic valve, and the main branches of the aorta such as the common carotid artery, renal artery involvement, etc., the dissection of the aneurysm Positive signs of aortic angiography: the contrast agent is divided into two channels in the aorta and the shape is not smooth, the contrast agent fails to enter the main branch of the aorta and the aortic valve is incomplete.
Four-dimensional echocardiography
The aortic intimal rupture flap at the entrance to the dissection aneurysm can be displayed.
Diagnosis
Diagnosis and diagnosis of thoracic aortic dissection
The disease should be differentially diagnosed with the following diseases:
(1) The torn inner membrane is distinguished from the artifact, the former being a thin and slightly curved line-like structure, and the strip artifacts appearing as a thicker straight line structure.
(2) When the false lumen is filled with a thrombus, it must be differentiated from the thrombosis of the aneurysm. The true aortic aneurysm is characterized by a single developed and dilated lumen surrounded by a thin aortic wall, plus the circumference of the aortic wall. Sexual calcification, while the aortic dissection is characterized by two developing lumens separated by a thin inner membrane or the development time and speed of the two lumens are different.
(3) Pay attention to the identification of adjacent normal or abnormal anatomical structures.
