Aorta: Open Repair of Abdominal Aortic Aneurysms (AAA)
The aorta is the large blood vessel that carries blood from the heart to the organs and peripheries. 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.
The gold standard treatment for an Abdominal Aortic Aneurysm (AAA) in a fit patient is an Open Repair of the AAA as it has better long-term durability.
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
- Saccular aneurysms
- Distal embolisation
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 (EndoVascular Aortic Repair (EVAR)) is recommended as the operative mortality and morbidity is less. Some criteria for selecting aortic stenting include:
- Age more than 65 years
- Poor cardiac function, e.g. Left Ventricular Ejection Fraction < 40%
- Poor lung function
- Diminished functional status
- The surgery is performed under General Anaesthesia.
- A long midline incision is made in the abdomen from the bottom of the sternum to the top of the pubic bone.
- The bowel loops are carefully moved aside and the aortic aneurysm exposed.
- A large clamp is placed across the aorta and applied to stop blood flow into the aorta.
- The enlarged aorta is opened up and a Dacron graft is sutured in its place.
- The aorta is closed, the abdominal wall is repaired and the skin layer is closed with metal staples.
The patient will usually be monitored overnight in the Surgical Intensive Care Unit. Due to the significant stress of the surgery and the long abdominal incision, the patient will usually be kept on a mechanical ventilator and deeply sedated overnight.
Over the course of the next few days, the patient’s condition will be closely monitored. The airway tube and mechanical ventilator will be removed once the patient is able to breathe adequately on his own.
Bowel function may take 5 to 7 days to recover after a major operation. In the meantime, the ICU team may start the patient on intravenous nutritional supplementation.
The patient will be encouraged to ambulate after 3 to 4 days and regular chest physiotherapy will help with breathing.
Most patients will be ready for discharge after 7 to 10 days’ stay in the hospital, provided the recovery is uncomplicated.
This surgery is associated with a mortality risk of between 4 to 8% in an elective setting. The major cause of death is usually due to cardiac complications.
Major complications that may occur include:
- Cardiac complications, e.g. heart attack during and after surgery
- Lung complications, e.g. pneumonia, atelectasis
- Kidney impairment
- Wound infection and haematoma
- Graft infection is a rare but fatal complication
- Urinary tract infection
- Femoral artery thrombosis
- Distal embolization after cross-clamping the aorta
- Tetraplegia, rare complication reported after clamping the aorta above the level of the kidney arteries
One option to open repair of AAA is to perform an EndoVascular Aortic Repair (EVAR), also known as Endovascular Stenting of the Aorta
Non-intervention is also an alternative especially in patients with very poor premorbid condition and where the life expectancy is limited.