What Is a Dissecting Aneurysm?

Aortic dissection aneurysm is a relatively rare and fatal disease, and its occurrence is related to many diseases. Hypertension is an important cause of aortic dissection. About 70% of patients have a history of hypertension, and distal aortic dissection with hypertension is more common. This may be related to the long-term stimulation of the aortic wall by hyperdynamic blood pressure, which keeps the tension of the aortic wall always in a tense state, and it is also related to the cystic or necrosis often occurring in collagen and elastic tissues; during atherosclerosis, the middle layer of the arteries is also positive. The benefits are in the aging process; hereditary diseases of connective tissues, such as Marfan syndrome, have congenital aortic degeneration. Proximal aortic dissection is a serious complication of Marfan syndrome; some congenital cardiovascular diseases such as aortic constriction and aortic valvularization may also cause aortic dissection. Pregnancy, severe trauma, heavy physical labor, and certain drugs are also factors in the pathogenesis of dissecting aneurysms.

Basic Information

English name: aorticdissectiveaneurysm
Visiting department: Cardiovascular Surgery

Multiple groups: 50 70 years old male
Common symptoms: Pain, shock, collapse, and changes in blood pressure

Causes of aortic dissection aneurysms

The cause is unknown. Most patients with aortic dissection have hypertension, and many have cystic middle layer necrosis. Hypertension is not the cause of cystic middle layer necrosis, but it can promote its development. Clinical and animal experiments have found that it is not the height of blood pressure but the amplitude of blood pressure fluctuations that is related to aortic dissection. Aortic cystic middle layer necrosis is quite common in Marfan syndrome, and there are many opportunities for aortic dissection. Other genetic diseases such as Turner syndrome and Et-Don syndrome also tend to occur aortic dissection. . Aortic dissection is also easy to occur during pregnancy. The cause is unknown. It may be that the endocrine changes during pregnancy change the structure of the aorta and easily crack.

The aortic wall tolerance pressure in normal adults is quite strong, which requires more than 66.7kPa (500mmHg) for intra-articular dehiscence. Therefore, the prerequisite for dissection of the dissection is the defect of the arterial wall, especially the defect of the middle layer. Generally speaking, in the elderly, middle-layer muscle degeneration becomes the main, and in young people, the lack of elastic fibers is the main. As for the few aortic dissections without arterial endometrial fissures, it may be caused by intramural hemorrhage due to the rupture of the nourishing blood vessels in the middle degenerative lesion. People with atherosclerosis are more likely to cause aortic dissection.

Aortic dissection aneurysm clinical manifestations

The disease is usually severe, with sudden severe pain, shock, and hematoma compressing the organ aorta when the corresponding aortic branch blood vessels appear. Some patients died of cardiac complications such as cardiac tamponade and arrhythmia during the acute phase (within 2 weeks). The peak age is 50 to 70 years, and the incidence rate is higher in men than in women.

Pain

Because of the prominent and characteristic symptoms of this disease, some patients have sudden, sudden, intense and persistent and intolerable pain. Unlike myocardial infarction, the pain gradually increases and is not as severe. The painful area may sometimes indicate the part of the torn mouth; if only fore chest pain, more than 90% is in the ascending aorta, and pain in the neck, throat, jaw, or face is also a strong suggestion of ascending aortic dissection. If it is the most painful between the shoulder blades, 90 More than% are in the descending aorta. Pain in the back, abdomen, or lower limbs also strongly suggests dissection of the descending aorta. Very few patients only report chest pain, which may be chest pain due to cardiac tamponade caused by the external breach of the ascending aortic dissection into the pericardial cavity. Sometimes the diagnosis of aortic dissection should be ignored and should be paid attention to.

2. Shock, collapse, and changes in blood pressure

About half or one third of the patients have pale, sweaty, damp and cold skin, shortness of breath, pulse rate, weak pulse or disappearance after the onset of the disease, and the degree of blood pressure drop is often not parallel to the above symptoms. Some patients may experience severe pain or even increased blood pressure. Severe shock is only seen when a dissection tumor breaks into the pleural cavity and bleeds heavily. Hypotension is mostly caused by cardiac tamponade or acute severe aortic valve insufficiency. The blood pressure and pulse of both limbs are obviously asymmetric, which often indicates the disease highly.

3. Other system damage

Because the expansion of dissection hematoma can compress the adjacent tissues or spread to the aortic branches, resulting in different symptoms and signs, resulting in complicated clinical manifestations and should be paid great attention.

Aortic dissection aneurysm

Electrocardiogram

May show left ventricular hypertrophy, non-specific ST-T changes. When the lesion involves the coronary arteries, acute myocardial ischemia or even acute myocardial infarction may occur. Electrocardiogram changes of acute pericarditis may occur during pericardial hemorrhage.

2.X-ray

A plain chest radiograph showed an increase in the upper mediastinum or aortic arch shadow, an irregular aortic shape, and a local bulge. If you see aortic intima calcification, you can accurately measure the thickness of the aortic wall. Normally between 2mm and 3mm, when it increases to 10mm, it indicates the possibility of dissection. If it exceeds 10mm, it is definitely the disease. Aortic angiography can show the location of the fissure, clear branch and aortic valve involvement, and estimate the severity of aortic valve insufficiency. The disadvantage is that it is an invasive examination, which is dangerous during surgery. CT can show dilated aorta. Aortic intimal calcification was found to be better than plain radiographs. If the calcified intima is shifted to the center, it will indicate aortic dissection. If it is shifted to the periphery, it will indicate a simple aortic aneurysm. In addition, CT can also show the intimal flap due to aortic intimal tear, which divides the aortic dissection into true cavity and false cavity. CT has high accuracy for the dissection of descending aortic dissection. Ascending and aortic segments of the aorta can produce false positives or false negatives due to arterial distortion. However, CT is difficult to determine the location of the cleft and the branch vessels of the aorta, and the existence of aortic valve insufficiency cannot be estimated.

3. Echocardiography

It is of great significance in the diagnosis of ascending aortic dissection, and it is easy to identify complications (such as pericardial hemorrhage, aortic valve insufficiency, and pleural hemorrhage, etc.). In M-mode ultrasound, the aortic root is enlarged, and the aortic wall at the dissection is changed from a normal single echo zone to two separate echo zones. In the two-dimensional ultrasound, it can be seen that the endometrial sheet with active internal separation shows an intimal swing sign, and the aortic dissection separates to form aortic true-false double-chamber sign. Sometimes pericardial or pleural effusions are visible. Doppler ultrasound can not only detect abnormal blood flow between the double echoes of the wall of the aortic dissection, but also has important diagnostic value for the classification of aortic dissection, the location of the breach and the quantitative analysis of aortic valve reflux . Application of esophageal echocardiography. It is reliable to observe the ascending aortic dissection with real-time color blood flow imaging. It also has high specificity and sensitivity to the descending aortic dissection.

4. Magnetic resonance imaging (MRI)

MRI can directly show the true and false lumen of the aortic dissection, clearly show the location of the endometrial tear and the peeled endometrium or thrombus. Can determine the extent and type of dissection, and the relationship with the aortic branch. However, the disadvantage is that the cost is high, the aortic valve insufficiency cannot be detected directly, and it cannot be used for patients with pacemakers and metal objects such as artificial joints and steel needles.

5. Digital Subtraction Angiography (DSA)

Non-invasive DSA is more accurate in the diagnosis of B-type aortic dissection. The location and scope of the dissection can be found, and sometimes the torn endometrial patch can be seen, but it has less diagnostic value for A-type lesions. DSA can also show the hemodynamics of the aorta and the perfusion of the main branches. It is easy to detect calcifications that cannot be detected by angiography.

6. Blood and urine tests

White blood cell counts often increase rapidly. Hemolytic anemia and jaundice can occur. There may be red blood cells in the urine, and even gross hematuria.

Aortic dissection aneurysm diagnosis

Various examination methods are of great help in establishing aortic dissection. Echocardiography, CT scan, and magnetic resonance can be used for diagnosis. It is still necessary to consider the aortic angiography of the operator.

Differential diagnosis of aortic dissection aneurysms

Severe chest pain, high blood pressure, sudden aortic insufficiency, unequal pulses on both sides, or pulsatile mass should be considered. Chest pain is often considered an acute myocardial infarction. However, chest pain begins to be less severe during myocardial infarction, gradually worsens, or worsens, and does not radiate below the chest. It can be effective with painkillers, accompanied by characteristic changes in electrocardiogram. The blood pressure is often low and does not cause pulses on both sides. The above points are fully identified.

Aortic dissection aneurysm treatment

Once suspected or diagnosed as the disease, it should be hospitalized. The purpose of treatment is to reduce myocardial contractility, slow down left ventricular contraction speed and peripheral arterial pressure. The goal of treatment is to control the systolic blood pressure at 13.3 to 16.0 kPa (100 to 120 mmHg) and the heart rate to 60 to 75 beats / minute. This can effectively stabilize or terminate the continued separation of the aortic dissection, so that the symptoms are relieved and the pain disappears. Treatment is divided into two phases: emergency treatment and consolidation treatment.

Emergency treatment

(1) Use morphine and sedatives for pain relief .

(2) Blood volume transfusion.

(3) Antihypertensive patients with hypertension may use intermittent intravenous administration of propranolol and intravenous drip of sodium nitroprusside to adjust the drip rate to reduce blood pressure to clinical treatment indicators. Significant reduction or disappearance of pain after blood pressure drop is a clinical indication that dissection separation has stopped expanding. Other drugs such as verapamil, nifedipine, captopril and prazosin can be selected. Reserpine intramuscular injection is also effective. In addition, labetalol can also be used, which has a double blocking effect of and , and can be administered intravenously or orally. It should be noted that: Hypertensive patients with aortic obstruction are not allowed to use antihypertensive therapy because hypotension can aggravate ischemia. For those with low blood pressure, antihypertensive drugs are not used, but can be used to reduce myocardial contractility.

2. Consolidation treatment

Proximal aortic dissection, ruptured or near-disrupted aortic dissection, and patients with aortic valve insufficiency should be treated with surgery. For slowly developing and distal aortic dissections, medical treatment can continue. Keep the systolic blood pressure at 13.3 ~ 16.0kPa (100 ~ 120mmHg). If the above drugs are not satisfactory, you can take captopril orally.

3. Surgical treatment

Stanford A (equivalent to Debakey I and II) requires surgical treatment. Debakey I surgical method is ascending aorta + aortic arch prosthesis replacement + modified stent elephant trunk surgery. Debakey surgical method is ascending aortic prosthesis replacement.

If aortic valve insufficiency or coronary artery involvement is involved, aortic valve replacement and Bentall's surgery are also required.

4. Interventional Therapy

At present, Stanford type B (equivalent to DeBakey type III) is the first choice for percutaneous stent implantation, and surgical treatment is necessary.

Aortic dissection aneurysm prognosis

Most cases die within a few hours to a few days after the onset of the disease, and the mortality rate is 1% to 2% per hour within the first 24 hours, depending on the extent and extent of the lesion. The more distal, the smaller the range and the less bleeding The prognosis is better.

Aortic dissection aneurysm prevention

Patients with hypertension should monitor blood pressure changes at least twice a day, adopt a healthy lifestyle, rationally apply drugs, control blood pressure in a normal range, appropriately limit physical activity, and avoid the occurrence of diseases caused by excessive exercise. Patients with aortic valve mitral valve malformation and Marfan syndrome should limit strenuous activities, regular physical examination to monitor changes in conditions, and timely surgical treatment to prevent the occurrence of aortic dissection.