Overview: What is an aortic dissection?
An acute aortic dissection results in a tear in the inner layer of the aorta. This causes blood to penetrate the wall layers and split them open (Latin dissecare = to cut). In the majority of cases, the thoracic aorta is affected, whereby a rough distinction is made as to whether the tear occurs close to the heart (type A according to Stanford) or only after the left shoulder artery (subclavian artery; type B according to Stanford) has departed.
The symptoms of an acute aortic dissection are severe chest or back pain that can radiate to various other parts of the body. In addition, shortness of breath and many other symptoms can occur if organs that are normally supplied with blood by the affected section of the aorta are damaged. As a rule, the pain is described as so-called “annihilation pain”, as something “unprecedented”. Very rarely there are no symptoms.
Type A aortic dissection is life-threatening, as it can lead to a heart attack or stroke. Doctors must treat the disease immediately – then the chances of survival increase. In the event of any suspicion, call the emergency number 144 immediately! Most people do not survive a complete aortic rupture.
Aortic dissection can be caused by diseases that weaken the layers of the aorta over time. High blood pressure (hypertension) or arteriosclerosis in particular have a damaging effect on the blood vessels. They stress the main artery and lead to wall damage. Hereditary diseases of the connective tissue (for example Marfan or Ehlers-Danolos syndrome) or trauma (injuries), for example as a result of an accident, can also cause an aortic dissection.
Acute aortic dissection type A is usually an emergency. We have to operate immediately to restore normal blood flow and thus ensure organ function. This is the only way those affected have a chance of survival. Acute aortic dissection type B usually does not require surgery, but initially requires intensive medical monitoring, blood pressure control and adequate pain therapy.
Aortic dissection – frequency and age
Experts put the frequency of aortic dissection at around 3 per 100,000 inhabitants per year. Aortic dissection occurs more frequently at an advanced age. On average, those affected are around 60 years old. One reason for this is that many people suffer from diseases such as arteriosclerosis (hardening of the blood vessels), hypertension (high blood pressure) or diabetes mellitus (diabetes) as they get older. These diseases weaken and damage the vessel walls and make them more susceptible to rupture. Abdominal aortic aneurysm – a risk factor for aortic dissection – is also more common in older people. And because the population is ageing, experts expect the number of aortic dissections to rise.
There are differences in frequency between the sexes: men are affected by aortic dissection about three times as often as women.
Aortic dissection: causes and risk factors
The cause of aortic dissection is a tear in the inner layer of the aorta. The aorta has a total of three wall layers:
- inner layer (intima) of vascular cells
- middle layer (media or tunica media) of muscle cells
- outer layer (adventitia or tunica externa) of connective tissue
Through the tear in the intima (usually in the thoracic aorta), blood penetrates the middle layer and separates the wall layers from each other. This creates 2 channels: a so-called “false” channel and the original “true” channel through which the blood flows. Depending on which channel the vessels branch off from and which channel is better supplied with blood, organs can no longer receive sufficient oxygen and nutrients due to the reduced blood flow. Type A aortic dissection can affect the heart and the brain. In type B aortic dissection, the organs in the abdomen and the legs. Due to the high pressure in the vessel wall, even the outer wall of the aorta can burst open – resulting in an aortic rupture.
Aortic dissection can occur in various places
The aorta is the central, largest and thickest artery in the body. It runs from the left ventricle in an arc through the chest. It has many branches in various parts of the body and supplies them with blood, oxygen and nutrients: Head, arms, abdomen (where it branches off into the pelvic vessels), liver, spleen, intestines and kidneys. It can be roughly divided into the following sections:
- Aorta ascendens: The ascending section of the aorta that starts from the left ventricle. The beginning lies within the pericardium. Two branches branching off from it supply the heart muscle.
- Aortic arch (Arcus aortae): The second section begins at the point where the aorta passes through the pericardium. The aorta bends upwards and diagonally backwards to the left. Three outgoing branches supply the arms, head and neck.
- Aorta descendens: The descending branch of the main artery runs through the chest cavity (thoracic aorta, supplies the chest wall, for example) and then passes through the diaphragm.
- Abdominal aorta: After passing through the diaphragm, it finally reaches the abdominal cavity (abdominal aorta, supplies the abdominal organs). At the level of the navel, the aorta branches into the two iliac arteries, which in turn supply the pelvis and legs with blood.
Aortic dissection can occur at various points along the course of the aorta:
- Aorta ascendens: approximately 65 percent
- Aortic arch: about 5 to 10 percent
- Descending aorta: approximately 20 to 25 percent
- Abdominal aorta: about 5 to 10 percent
Risk factors for aortic dissection
Diseases that weaken the vessels over time are often responsible for aortic dissection. However, trauma (injuries) can also cause a tear in the vessel wall.
Factors favoring aortic dissection
- Age: the risk increases with age
- Gender: men are significantly more frequently affected
- Arteriosclerosis (vascular calcification)
- Hypertension (high blood pressure)
- Diabetes mellitus
- Aortic aneurysms
- Vascular inflammation affecting the aorta, for example Takayasu’s arteritis
- Genetic (hereditary) diseases, for example Marfan syndrome, Turner syndrome, Ehlers-Danlos syndrome, bicuspid aortic valve (a congenital heart valve defect)
- Drug abuse (amphetamines, cocaine)
- Traffic accidents, fall from a great height
- heavy physical exertion
- sometimes: surgical interventions, treatment using catheters
Symptoms: Aortic dissection causes severe chest pain
Acute aortic dissection is an emergency. The chances of survival increase if you act quickly and doctors can start treatment immediately.
The most important symptom of acute aortic dissection is:
- Sudden onset of severe chest or back pain when the thoracic aorta is affected. Many experience the pain as stabbing or tearing and describe it as “annihilation pain”, some also like an “axe blow”. The pain can radiate to other areas of the body, such as the neck, arms or between the shoulder blades. In the case of a dissection of the abdominal aorta, the pain often radiates to the abdomen, back or legs. If the visceral vessels are blocked, those affected experience colicky pain (severe pain around the navel that is independent of movement and usually similar to contractions).
Symptoms when organs are no longer supplied with blood
Depending on the location of the tear, various organs are then no longer supplied with sufficient blood. These circulatory disorders can lead to other symptoms, for example:
Diagnosis of aortic dissection
The diagnosis of aortic dissection always begins – if the affected person is responsive – with questions about the symptoms. An important indication is severe chest pain. The emergency doctor will try to make a diagnosis and start treatment as quickly as possible. This increases the chances of survival. The following examinations help with the diagnosis:
- Physical examination with pulse and blood pressure measurement: A sudden difference in blood pressure in the extremities in combination with chest pain is the most important indication of an aortic dissection. We also listen to the heart sounds with a stethoscope and check the mobility of the arms and legs.
- Blood test: We determine various blood values, including D-dimers, C-reactive protein (CRP), troponin I, creatine kinase and lactate.
- Electrocardiography (ECG) to check heart activity
- Transesophageal echocardiography (TEE): An ultrasound examination in which we insert a flexible instrument (endoscope) with a transducer into the esophagus.
- Computed tomography (CT): An X-ray examination that provides cross-sectional images of the inside of the body.
Aortic dissection type A and type B
We distinguish between two types of aortic dissection (according to the Stanford classification) – depending on the section of the aorta that is affected. Treatment also depends largely on this.
- Standford type A: The tear is located in the section of the aorta where it leaves the heart and joins the ascending part (ascending aorta). This is the most common type of aortic dissection – and also the most dangerous. This is because the risk of a heart attack, a sleep attack or an aortic rupture is high.
- Stanford type B: The tear is located in the descending part of the aorta (aorta descendens). This type occurs less frequently and is less dangerous, unless the blood supply to organs such as the liver, intestines, kidneys or the blood supply to the legs is obstructed.
Once an aortic dissection has been diagnosed, we start treatment immediately to improve the chances of survival.
Aortic dissection: prevention, early detection, prognosis
Various diseases play a role in aortic dissection, such as high blood pressure, arteriosclerosis or diabetes mellitus. All of them damage and weaken the vascular walls. You can protect your blood vessels to a certain extent by leading a healthy lifestyle – and thus possibly prevent an aortic dissection. Some tips:
- Do not smoke and if you do smoke: Try to give up smoking. Get professional support if you can’t do it alone.
- Make sure you eat a healthy and balanced diet, for example with plenty of fruit, vegetables and wholegrain products, but little meat, sausage and saturated fats.
- Make sure you get plenty of exercise in your everyday life and do sport, preferably endurance sport.
- Drink only a little alcohol and take regular alcohol breaks.
- Make sure you maintain a healthy body weight. Overweight and obesity also affect your blood vessels. If necessary, try to lose a few kilos. This is best achieved with a healthy diet and plenty of exercise.
In the case of high blood pressure or elevated blood lipids, these should be adequately treated with medication. A healthy lifestyle can also improve these values.
You may also be able to prevent an aortic aneurysm, which is also a risk factor for aortic dissection, through your lifestyle. For abdominal aortic aneurysms, an ultrasound examination of the abdominal cavity is recommended for people at risk from the age of 65, such as smokers. Preventive surgery is also an option if a certain diameter has been reached and there is a risk of aortic rupture.
And because aortic dissection can also be caused by accidents: Always fasten your seat belt in the car to reduce the risk of injury in the chest area.
Course and prognosis of aortic dissection
Acute aortic dissection is a life-threatening condition. Aortic dissection type A is particularly dangerous and is also the most common case. This is where the risk of a stroke, heart attack or aortic rupture is highest. However, thanks to faster diagnosis and surgery, more affected people survive today than a few years ago. Nevertheless, some patients unfortunately die within the first few days or weeks.
After the acute phase, which is usually over after 14 days, it is referred to as a chronic aortic dissection. At this stage, the vessel wall becomes increasingly stable. However, if risk factors such as smoking persist, high blood pressure is not properly controlled or the person concerned has genetic causes, the aorta can dilate over the years. An aneurysm forms. This usually affects the entire aorta (thoraco-abdominal aortic aneurysms). There is a renewed risk of aortic rupture. The earlier a growth of the aorta is recognized, the better. Regular follow-up checks (once a year) are therefore essential.
Aortic dissection: treatment must begin as soon as possible
Acute aortic dissection is an emergency that requires immediate treatment. First, the emergency doctor administers painkillers and medication to lower the blood pressure. Surgery is then often unavoidable. The procedure chosen by doctors depends on the section in which the inner layer of the aorta is torn (type A or B).
- Type A aortic dissection must be operated on as quickly as possible. The affected section of the aorta is usually replaced with a vascular prosthesis, usually made from artificial tissue. If necessary, we also replace the aortic valve during the surgical procedure.
- In the case of a type B aortic dissection, blood pressure and possible pain are usually first controlled with medication under intensive medical supervision. Surgery is necessary if vascular outlets are obstructed (impending organ hypoperfusion) or an aortic rupture is imminent. During the operation, we implant a covered vascular support (stent graft). This is intended to seal the tear and restore normal blood flow in the “true channel”.
In case of a surgical intervention, the Institute of Anesthesiology will select the anesthesia procedure that is individually adapted to you.
Whether with or without surgery, it is important that affected people undergo regular check-ups with their doctor. For example, they check the general state of health, the aortic dissection and check the position of the vascular prosthesis or stent graft if one has been implanted. Possible complications and consequences can thus be detected and treated in good time.