Therapy of the aortic aneurysm
Overview - Conservative
A conservative therapy of the aortic aneurysm includes waiting with regular ultrasound checks. The therapy is indicated primarily for small aneurysms and those of type III. The aortic aneurysm must not increase in size more than 0.4 cm annually. Furthermore, the accompanying or causative diseases must be treated. It is essential to ensure that the blood pressure is adjusted. The blood pressure in aneurysm patients should be a maximum of 120: 80 mmHg.
Overview - Interventions
Radiological therapy may be indicated in younger patients with small aneurysms or trauma to the descending aorta. In this case, a groin vessel is opened parallel to the imaging, a plastic-coated tube (stent) is inserted into the vascular system by means of a catheter and advanced to the aneurysm site.
One advantage of this therapy is the avoidance of an expensive operation, a disadvantage is the reduced sealing of the aneurysm site. Surgical therapy is necessary if the aneurysm is symptomatic or torn (emergency surgery).
Non-symptomatic aneurysms may also require surgery under certain circumstances (see below).
Operation of an aortic aneurysm
First of all, the thorax is opened during the operation and the vessels are shown. It is necessary to separate the affected vessel from the rest of the bloodstream during the operation so that the operation can be carried out without bleeding (clamping of the aorta).
Here the so-called heart-lung machine is used, which diverts the blood that normally flows through the main artery. In the case of bag-shaped aneurysms, the bulge is removed and the rest sutured.
In the case of short aneurysms, after the bulge has been removed, the freed ends of the main artery are brought together again and sutured.
Aneurysms of the dissecan type I and II are supplied with a plastic prosthesis. For this purpose, the prosthesis is pretreated in the so-called blood bath shortly before the operation. This causes the blood to flow around and seal the plastic. During the operation, this so-called stent is then brought to the place where the aneurysm is located.
To do this, it must be opened, the stent inserted and then the aneurysm sutured over it.
Read more on the topic Aortic prosthesis.
When do you need an operation?
An indication for surgery is when there is an increased risk of rupture, i.e. tearing of the aortic aneurysm. The risk of dying from a spontaneous rupture must be greater than the risk of an operation. In principle, an aneurysm diameter of more than 5 cm is considered the limit for a relevant risk.
The more risk factors there are, the more likely an operation is advisable. Other factors are:
- Enlargement of the aneurysm by more than 1 cm per year
- irregular bulges on the wall
- remaining blood flow in wrong lumen
- high blood pressure
- chronic lung disease (COPD)
- Inflammation of the aorta
- Nicotine consumption
- familial accumulation.
Non-symptomatic aneurysms are also an indication for surgery, if
- the patients are younger than 70 years and have no risk factors for surgery.
- it is an elderly patient with an aneurysm size greater than 5-6 cm.
- when Marfan syndrome patients have an aneurysm greater than 4 cm in diameter.
The final decision about the operation should be made by an experienced vascular surgeon considering all risk factors and other diseases of the patient.
What are the different surgical methods?
Basically, one can differentiate between an open surgical procedure and a so-called endovascular aneurysm elimination (EVAR for short). As a rule, minimally invasive EVAR is preferred because it is less stressful for the patient than a large, open procedure. In the long term, however, the advantages and disadvantages of both methods balance each other out.
In EVAR, a catheter procedure, similar to the implantation of a stent after a heart attack, is used to insert a prosthesis through the inguinal artery (so-called.Stent graft) advanced to the aneurysm in order to bridge it after the stent graft has been deployed. For this, however, certain conditions must be present, for example certain distances to the vessels branching out from the aorta, low calcification of the arteries or good kidney function. To check the stent graft, CT checks must be carried out at regular intervals, which, however, is often an exclusion criterion for young patients.
The open procedure can be chosen for more complicated aneurysms or young patients. The abdominal cavity is opened either with an abdominal incision (median laparatomy) or flank incision (retroperitoneal access), the organs are carefully pushed aside and the aorta is exposed so that healthy vascular walls can be seen again at the top and bottom. Then the aorta is clamped off and the aneurysm is replaced with a vascular prosthesis. A heart-lung machine must be used if the aorta near the heart is aneurysm in the chest.
Duration of the operation
The duration of the operation depends largely on the procedure chosen. The minimally invasive EVAR usually takes less time than the open surgical procedure, as the access route via the groin to the aorta is more direct and faster. EVAR takes an average of one and a half to two hours, and open surgery takes at least three or longer, depending on the complication.
Risks of the operation
First of all, a distinction is made between risks that are directly related to the operation and risks that may arise years later.
The direct perioperative risks are significantly greater with the open procedure than with EVAR. General risks, as with any procedure, are
- Bleeding,
- Injury to nerves,
- Scarring and
- Infections.
In open surgery, the risk of blood loss or a reduced blood supply to the abdominal organs is more relevant than with EVAR. Likewise, there is a higher likelihood of damaging the nerve plexus surrounding the aorta, which can lead to disruptions in ejaculation.
With EVAR, on the other hand, there is a higher risk that the prosthesis will loosen over time and slip within the aorta (so-called dislocation). In addition, so-called endoleaks can occur more frequently than in open surgery, in which the aneurysm is supplied with blood again despite the stent graft.
With both procedures, new aneurysms can develop in the long term, preferably at the edges of the inserted prosthesis, as well as seam insufficiencies with life-threatening bleeding into the abdomen.
The risk of dying in an open operation is on average 5-7%, in a specialized center and fewer risk factors it is lower. The risk of dying directly with EVAR is somewhat lower, but in the long term the mortality rates will even out due to the increased complication rate with EVAR compared to open surgery. After five years, around 60-75% of patients are still alive.
Which drugs are used?
The most important drug therapy for the aortic aneurysm is the regulation of blood pressure. Since high blood pressure (hypertension) promotes the rupture of the aneurysm, the blood pressure must be strictly set to values below 120-140 mmHg systolic to 90mmHg diastolic. Regular blood pressure medication, so-called antihypertensive drugs, are also used. They are administered according to a certain level scheme, building on each other, depending on the severity and uncontrollability of the hypertension. ACE inhibitors, such as e.g. Ramipril, or AT1 antagonists, e.g. Candesartan. Beta blockers (e.g. metoprolol) are often given in combination. Blood lipid lowering drugs, such as statins, also have a positive effect, as they stop the progression of the changes in the vascular wall.
Read more about antihypertensive drugs.
Which medication shouldn't be given?
Since beta blockers are often used for therapy, calcium antagonists such as Verapamil or diltiazem. This arises from the pharmacological properties of both drugs.
The use of blood-thinning medication must be decided in advance on a case-by-case basis. However, they are mandatory after the graft has been installed. In general, however, nicotine has a significant negative effect on the course of an aortic aneurysm and abstinence from tobacco and any form of nicotine is highly recommended for aortic aneurysm.
Prophylaxis of an aortic aneurysm
Apart from an optimal blood pressure setting (max: 120: 80 mmHg) you cannot influence the formation of an aortic aneurysm yourself. It is important to postpone arteriosclerosis for as long as possible by adopting an appropriate lifestyle, to recognize an aneurysm as early as possible by means of prophylactic ultrasound examinations and to monitor its progress (especially if there is a genetic predisposition).
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