What is the aorta
The aorta is the largest vessel in the human body, which carries blood from the heart to the organs and limbs. The upper section of the aorta runs inside the chest, this section is called the thoracic aorta . The lower part is in the abdominal cavity and is called the abdominal aorta . It delivers blood to the lower part of the body. In the lower abdomen, the abdominal aorta divides into two large vessels - the iliac arteries , which carry blood to the lower extremities.
The aortic wall consists of three layers: internal (intima), middle (media), external (adventitia).
Classification of pathology
There are several classification systems for aortic dissection.
Cardiac surgeon Michael de Baiki proposed a system based on the anatomical location and extent of damage to the vascular wall. The types of dissection are as follows: • Type I – the pathological process involves the ascending part, the arch and, often, the descending part of the aorta;
• Type II – only the ascending aorta is affected;
• Type III – the descending aorta is subject to dissection:
a – the process is limited to the thoracic region;
b – the process also affects the abdominal region.
The clinical classification, called Stanford, divides two options:
• A – the ascending section is affected, regardless of the location of the initial tear of the internal choroid;
• B – the lesion does not affect the ascending part, that is, it begins below the origin of the left subclavian artery.
According to the course, the process of aortic dissection is divided into acute and chronic . A dissection is considered chronic when more than 14 days have passed since its onset, or it is discovered accidentally in the absence of clinical manifestations.
Abdominal aortic aneurysm
Abdominal aortic aneurysm is a chronic degenerative disease with life-threatening complications. An abdominal aortic aneurysm is defined as an increase in its diameter by more than 50% compared to the norm or a local bulging of its wall. Under the pressure of blood flowing through this vessel, the dilatation or bulging of the aorta may progress. The diameter of a normal aorta in the abdominal region is approximately 2 cm. However, at the site of an aneurysm, the aorta can be dilated to 7 cm or more.
Why is an aortic aneurysm dangerous?
An aortic aneurysm poses a major health risk as it can rupture. A ruptured aneurysm can cause massive internal bleeding, which in turn leads to shock or death.
An abdominal aortic aneurysm can cause other serious health problems. Blood clots (thrombi) often form in the aneurysm sac or parts of the aneurysm tear off, which move with the blood flow along the branches of the aorta to the internal organs and limbs. If one of the blood vessels becomes blocked, it can cause severe pain and lead to organ death or loss of a lower limb. Fortunately, if an aortic aneurysm is diagnosed early, treatment can be timely, safe and effective.
After the procedure
First, the operated patient is transferred to the intensive care ward, where he spends a day under the supervision of anesthesiologists and resuscitators. There, the patient recovers from anesthesia with continuous monitoring of blood counts, diuresis, respiration, heart function and blood pressure.
The next day, the patient is sent to a regular ward, where he is given infusions to replenish blood loss and correct the electrolyte-water balance. Particular emphasis is placed on pain relief and antibacterial therapy.
The patient is prohibited from drinking for several hours after surgery. This helps avoid vomiting and nausea due to water entering the digestive tract. In general, the patient spends up to 4-7 days in the hospital. The full rehabilitation period covers up to 2-3 months.
Types of aortic aneurysms
There are “true” and “false” aortic aneurysms. A true aneurysm develops due to the gradual weakening of all layers of the aortic wall. A false aneurysm is usually the result of trauma. It is formed from the connective tissue surrounding the aorta. The cavity of the false aneurysm is filled with blood through a crack in the aortic wall. The aortic walls themselves do not participate in the formation of an aneurysm.
Depending on the form there are:
- saccular aneurysm - expansion of the aortic cavity on only one side;
- spindle-shaped (fusiform) aneurysm - expansion of the aneurysm cavity on all sides;
- mixed aneurysm - a combination of saccular and fusiform forms.
Causes and risk factors for the development of abdominal aortic aneurysm
The causes of the development of abdominal aortic aneurysms are very diverse. The most common cause of aneurysm development is atherosclerosis. Atherosclerotic aneurysms account for 96% of the total number of all aneurysms. In addition, the disease can be either congenital (fibromuscular dysplasia, Erdheim's cystic medianecrosis, Marfan syndrome, etc.) or acquired (inflammatory and non-inflammatory). Inflammation of the aorta occurs when various microorganisms invade (syphilis, tuberculosis, salmonellosis, etc.) or as a result of an allergic-inflammatory process (nonspecific aortoarteritis). Non-inflammatory aneurysms most often develop with atherosclerotic lesions of the aorta. Less commonly, they are the result of injury to its wall.
Risk factors for developing an aneurysm
- Arterial hypertension;
- Smoking;
- The presence of aneurysms in other family members. Which indicates the role of hereditary factors in the development of this disease;
- Gender: men over 60 years of age (abdominal aortic aneurysms occur less frequently in women).
Who is in more danger?
- Age - 50-79 years
- Gender – male (3 times more often)
- Smoking (increases risk 4-5 times)
- Patients with uncontrolled arterial hypertension (high blood pressure);
- Overweight patients;
- Patients with atherosclerotic lesions of blood vessels supplying the brain;
- Patients with impaired blood cholesterol metabolism (dyslipidemia);
- Patients whose relatives also had an aneurysm (the risk is doubled).
Men who smoke in adulthood are at greatest risk (statistically, every 10 have an aneurysm).
Symptoms and signs of abdominal aortic aneurysm
In most patients, abdominal aortic aneurysms occur without any symptoms and are an incidental finding during examinations and operations for other reasons.
When signs of an aneurysm develop, the patient experiences one or more of the following symptoms:
- A feeling of pulsation in the abdomen, similar to a heartbeat, an unpleasant feeling of heaviness or fullness.
- Dull, aching pain in the abdomen, in the navel area, usually on the left.
Indirect signs of abdominal aortic aneurysm are important :
- Abdominal syndrome. Manifested by the appearance of belching, vomiting, unstable stool or constipation, lack of appetite and weight loss;
- Ischioradic syndrome. Manifested by lower back pain, sensory disturbances and movement disorders in the lower extremities;
- Syndrome of chronic ischemia of the lower extremities. Manifests itself in the appearance of pain in the muscles of the lower extremities when walking, sometimes at rest, coldness of the skin of the lower extremities;
- Urological syndrome. It manifests itself as pain and heaviness in the lower back, difficulty urinating, and the appearance of blood in the urine.
Harbingers of rupture may be increased abdominal pain.
When an aneurysm ruptures, the patient suddenly feels an increase or appearance of abdominal pain, sometimes “radiating” to the lower back, groin area and perineum, as well as severe weakness and dizziness. These are symptoms of massive internal bleeding. The development of such a situation is life-threatening! The patient needs emergency medical care!
Diagnosis of abdominal aortic aneurysms
Most often, abdominal aortic aneurysms are detected by ultrasound examination of the abdominal organs. Typically, the discovery of an aneurysm is an incidental finding. If a doctor suspects a patient has an aortic aneurysm, modern diagnostic methods are used to clarify the diagnosis.
Methods for diagnosing abdominal aortic aneurysm
- Computed tomography in angio mode;
- Magnetic resonance imaging in angio mode;
- X-ray contrast aorto- and angiography;
- Ultrasound duplex or triplex angioscanning of the abdominal aorta.
If necessary, the abdominal and thoracic aorta is examined.
Treatment methods for aortic aneurysm
There are several methods for treating aortic aneurysm. It is important to know the advantages and disadvantages of each of these techniques. Approaches to the treatment of abdominal aortic aneurysms:
Monitoring the patient over time
If the aneurysm is less than 4.5 cm in diameter, the patient is recommended to be monitored by a vascular surgeon, since the risk of surgery exceeds the risk of rupture of the aortic aneurysm. Such patients should undergo repeated ultrasound examinations and/or computed tomography at least once every 6 months.
When the aneurysm diameter is more than 5 cm, surgical intervention becomes preferable, since as the size of the aneurysm increases, the risk of aneurysm rupture increases.
If the size of the aneurysm increases by more than 1 cm per year, the risk of rupture increases and surgical treatment also becomes preferable.
Open surgery: aneurysm resection and aortic replacement
Surgical treatment is aimed at preventing life-threatening complications. The risk of surgery is associated with possible complications that include heart attack, stroke, limb loss, acute intestinal ischemia, male sexual dysfunction, embolization, prosthetic infection, and renal failure.
The operation is performed under general anesthesia. The essence of the operation is to remove the aneurysmal expansion and replace it with a synthetic prosthesis. The average mortality rate for open procedures is 3-5%. However, it may be higher if the renal and/or iliac arteries are involved in the aneurysm, as well as due to the patient’s concomitant pathology. Observation in the postoperative period is carried out once a year. Long-term treatment results are good.
Endovascular repair of aortic aneurysm: installation of a stent graft
Endoprosthetics of aortic aneurysm is a modern alternative to open surgery.
The operation is performed under spinal or local anesthesia through small incisions/punctures in the groin areas. Through the above approaches, catheters are inserted into the femoral artery under X-ray control. According to which, in the future, the endoprosthesis will be brought to the aneurysmal extension. An endoprosthesis or stent-graft of the abdominal aorta is a mesh frame made of a special alloy and wrapped in synthetic material. The last stage of the operation is the installation of a stent graft at the site of the aneurysmal expansion of the aorta. Eventually, the aneurysm is “switched off” from the bloodstream and the risk of rupture becomes unlikely. After aortic replacement, the patient is observed in the hospital for 2-4 days and discharged.
This technique allows to reduce the incidence of early complications, shorten the length of patient stay in the hospital and reduce the mortality rate to 1-2%. Observation in the postoperative period is carried out every 4-6 months using ultrasound techniques, CT angiography, X-ray contrast angiography. The endovascular treatment method is certainly less traumatic. About 40,000 such operations are performed annually in the United States alone.
Thus, the choice of treatment method for abdominal aortic aneurysm is based on the individual characteristics of the patient.
Why is the procedure necessary?
This intervention helps prevent such a dangerous phenomenon as aneurysm rupture. If you ignore timely treatment, this can lead to death. According to statistics, in 40 out of 100 patients, rupture occurs during the first year of illness.
Consequently, resection saves lives and protects against various complications. In particular:
- prevents digestive tract disorders;
- relieves portal hypertension syndrome;
- prevents organic changes in the digestive system;
- does not allow intestinal ischemia to occur, etc.
