What is Aortic Dissection?

Aortic dissection refers to the blood in the aortic cavity entering the aortic medial membrane from the aortic intimal tear, separating the medial membrane, and expanding along the long axis of the aorta to form a true and false two-chamber separation state of the aortic wall. This disease is rare, with an incidence rate of 1 in 100,000 to 200,000 per year. The peak age is 50 to 70 years old, and the male to female ratio is about 2 to 3: 65% to 70% die from cardiac pressure in the acute phase. Congestion, arrhythmia, etc., so early diagnosis and treatment are very necessary.

Hypertension and arteriosclerosis

Aortic dissection accounts for 70% to 80% due to hypertension and atherosclerosis. Hypertension can make the arterial wall in a state of emergency for a long time, and cystic degeneration or necrosis of elastic fibers often occurs, leading to dissection.

Connective tissue disease

Marfan syndrome, Ehlers-Danlos syndrome (hyperelastic skin syndrome), Erdheim middle layer necrosis or Behcet disease, etc.

3. Congenital Cardiovascular Disease

Such as congenital aortic constriction secondary to hypertension or aortic valve valvular.

4. damage

Severe trauma can cause aortic isthmus tears, and iatrogenic injuries can also cause aortic dissection.

5. Other

Pregnancy, syphilis, endocarditis, systemic lupus erythematosus, multiple nodular arteritis, etc.

Pain

Most patients experience sudden chest and back pain. Type A is more common in the anterior chest and interscapular region, and type B is more common in the back and abdomen. The pain was severe and unbearable, peaked immediately after the onset, and was knife-shaped or torn. A few patients with slow onset may not have significant pain.

2. Hypertension

Most patients can be associated with hypertension. The patient presented with shock due to severe pain, anxiety, sweating, pale, and accelerated heart rate, but the blood pressure was often not low or even increased.

3. Cardiovascular symptoms

Aortic valve insufficiency occurs when the dissection hematoma affects the aortic valve annulus or affects the support of the leaflets. Diastolic murmurs can suddenly appear in the aortic valve area, and the pulse pressure widens. Acute aortic regurgitation can cause heart force. Exhaustion. Changes in pulse pressure are usually seen in the carotid, brachial, or femoral arteries, and the pulse on one side weakens or disappears, reflecting the compression of the aortic branches or the endometrial lobes blocking its origin. There may be pericardial friction sounds and pleural effusion.

4. Organ and limb ischemic manifestations

Neurological symptoms such as renal ischemia, lower limb ischemia, or paraplegia can occur when dissection involves visceral arteries, limb arteries, and spinal cord blood supply.

Electrocardiogram

No specific changes. When the lesion involves the coronary arteries, acute myocardial ischemia or even acute myocardial infarction may occur, but the ECG of one third of the patients is normal.

2. Chest X-ray

On the chest radiograph, the upper mediastinum or aortic arch is enlarged, the aorta is irregular in shape, and there are local bulges.

3. Echocardiography

The diagnosis of ascending aortic dissection is valuable and can identify complications such as pericardial hemorrhage, aortic valve insufficiency, and pleural hemorrhage.

4.CT inspection

Enhanced scans can show the true and false cavities and their sizes, as well as the location of splanchnic arteries, as well as understand the situation of thrombi in the false cavities.

5. Magnetic resonance imaging (MRI)

It is the clearest imaging method for detecting aortic dissection. It is considered the "gold standard" for the diagnosis of this disease.

6. Aortic angiography

Selective angiography of the aorta has been used as a routine test. The diagnosis of type B aortic dissection is more accurate, but the value of type A is less.

7. Intravascular ultrasound (IVUS)

IVUS can accurately identify the pathological changes by observing the structure of the tube wall directly from the aortic cavity. The sensitivity and specificity for the diagnosis of arterial dissection are close to 100%. However, they are both invasive tests, which are dangerous and not commonly used.

8. Blood and urine tests

There may be elevated C-reactive protein and a mild to moderate increase in white blood cell count. Bilirubin and LDH are mildly elevated, and hemolytic anemia and jaundice can occur. There may be red blood cells in the urine, and even gross hematuria. The increased concentration of myosin heavy chains in smooth muscle can be used as a biochemical indicator for the diagnosis of aortic dissection.

This disease should be considered for acute chest pain, high blood pressure, sudden aortic insufficiency, unequal pulses on both sides, or touching a pulsating mass. Chest pain is often considered as an acute myocardial infarction. However, when the myocardial infarction begins, the chest pain does not start to be severe, gradually worsens, or worsens, and does not radiate below the chest, with characteristic changes in the electrocardiogram. If there is a shock appearance, the blood pressure is often low. Does not cause pulses on both sides, the above points can be identified.

Echocardiography, CT, MRI and other examinations are of great help in establishing the diagnosis of aortic dissection. Aortic angiography or IVUS examination can be considered for those who are planning to undergo surgery.

1.Debakey typing

According to the location of the breach and the range of the interlayer, it is divided into three types.

Type I: The breach is located within 5 cm of the aortic valve. The proximal end involves the aortic valve, and the distal end involves the aortic arch, descending aorta, abdominal aorta, and even the iliac artery.

Type II: The breach location is the same as Type I, and the dissection is limited to the ascending aorta.

Type III: The breach is located 2 to 5 cm away from the opening of the left subclavian artery, involving the iliac artery distally.

2.Stanford typing

According to the needs of surgery, it can be divided into A and B types.

Type A: The breach is located in the ascending aorta and is suitable for emergency surgery.

Type B: Dissection lesions are limited to the abdominal aorta or iliac arteries, and can be treated firstly by medical treatment, and then open surgery or intracavitary treatment.

Any patient suspected or diagnosed with this disease should be admitted immediately to the ICU for treatment. Treatment is divided into non-surgical treatment and surgical treatment.

Non-surgical treatment

(1) For severe analgesia, morphine drugs can be given for analgesia, sedation and braking, pay close attention to changes in the nervous system, limb pulses, heart sounds, etc., detect vital signs, electrocardiogram, urine volume, etc., use nasal catheter to inhale oxygen to avoid input Too much fluid to avoid complications such as hypertension and pulmonary edema.

(2) Controlling blood pressure and reducing heart rate Combined use of -blockers and vasodilators to reduce vascular resistance, vascular wall tension and ventricular contractility, reduce left ventricular dp / dt, and control blood pressure to 100 to 120 mm Hg . The heart rate is between 60 and 75 beats per minute to prevent the lesion from expanding.

(3) Ventilation and supplementary blood volume Patients with severe hemodynamic instability should be intubated immediately and given supplemental blood volume.

2. Surgical treatment

Surgery is to remove the endometrial tear, prevent major bleeding caused by dissection of the dissection, and rebuild blood flow in the vascular occlusion area caused by the endometrium or false cavity.

(1) Type A aortic dissection To prevent acute type A dissection from rupturing or worsening, surgical treatment should be performed as soon as possible. Patients in the chronic phase also need surgery after observing changes in their condition. A type of dissection needs to be performed under extracorporeal circulation. The key to the operation is to find the location of the endometrial breach, and to determine the condition of the distal outflow tract of the dissection. Different surgical methods (ascending aorta replacement, Bentall surgery, Sun-type surgery, etc.) ). In recent years, scholars have tried endovascular treatment of type A aortic dissection.

(2) B-type aortic dissection vascular lumen technology and stent materials are continuously developed. B-type aortic dissections are more often covered with stent grafts, which has the advantages of less trauma, less bleeding, faster recovery, and lower mortality. It is especially suitable for Older people and poor general conditions who cannot tolerate traditional surgery have become the standard treatment for complex type B aortic dissection, and are also suitable for dissection cases involving aortic arch or visceral artery. Compared with traditional open surgery, the perioperative operation is reduced. Incidence of complications.