Aorta: Aortic Stenting
The aorta is the main blood vessel that carries blood from the heart to the organs and limbs. An aortic aneurysm is a condition where the aorta becomes distended and enlarged. As a result of the enlargement, the walls of the aorta become thinned out and more prone to rupture.
Aortic stenting is one of the treatment methods to prevent aortic rupture. This involves placing a stent-graft, a fabric covered metal tube, inside the aorta to depressurize the aortic sac and prevent it from rupturing.
Not all patients with aortic aneurysms will require intervention. The usual indications when an intervention should be offered include:
- Abdominal aorta greater than 5.5cm in widest diameter
- Rate of growth of aorta greater than 5mm in 6 months
- Symptomatic aneurysms
Generally, younger patients less than 55 to 60 years of age with good risk factors should consider an open surgical repair as it is more durable in the long run. For older patients who have more medical problems, the option of aortic stenting is recommended as the operative mortality and morbidity is less.
In order to assess if the patient’s aorta is suitable for stenting, a detailed CT scan will need to be done. This will allow the surgeon to decide if a stenting can be done, to plan for the procedure and to measure the aorta for the correct size of stent-graft to be deployed.
The surgery is performed under General Anaesthesia. In high-risk patients, the surgery can also be done under a Local Anaesthetic with monitored sedation.
- Incisions are made in both groins and the femoral arteries are identified.
- Sheaths are placed into the femoral arteries to allow access into the vessels.
- Catheters and wires are placed via these sheaths into the aorta.
- Contrast agent is injected into the aorta to visualise the aorta and its branches clearly.
- The aortic stent-graft is delivered from the femoral artery into the aorta.
- Once the position is satisfactory, the stent-graft is deployed and the delivery device removed.
- The femoral artery incisions are repaired and the wounds closed with sutures.
The patient will usually be monitored overnight in a high-dependency ward closely for the first 24 hours. Liquids will be allowed once the patient has recovered from the anaesthetic. The next day, the patient can take normal meals, get up and walk around with assistance.
Constant regular monitoring of the stent-graft will be required for the lifetime of the patient. This is usually done at a 3 monthly interval for the 1st year, 6 monthly for the 2nd year and yearly thereafter. This is to detect endoleaks – a condition in which there is continued pressurisation of the aortic sac from leaks around the stent-graft.
The reported mortality risk of this surgery is approximately 2-3%. This is lower than the mortality risk of open surgical repair of the aorta.
Other complications that may occur include:
- Cardiac, or heart complications
- Kidney impairment from the use of contrast agents during the surgery
- Femoral artery thrombosis, or clots
- Distal embolization, where clots flow down the leg and cause obstruction of flow distally
- Graft migration, where the graft slips downwards, causing leakage
- Graft failure, where either the fabric or metal component of the graft breaks down and may cause leakage or thrombosis
- Wound haematoma and infection
The traditional approach of an open surgical repair of the aorta is one alternative treatment, provided the patient is fit to undergo major aortic surgery.