Open Abdominal Aortic Aneurysm
The Aorta is the largest artery in the body commencing in the chest and running down to the pelvis. The section in the upper abdomen is prone to dilate in patients with certain risk factors.
These include men older than 65, those with long term high blood pressure, smokers – especially if their lungs are damaged and those with a positive family history.
As the Aorta enlarges it weakens until it gets to the point that it may rupture. This risk becomes significant when it is larger than 5.5 cm in men, 5 cm in women. Generally as the AAA enlarges there are no symptoms – although persistent, new, back and abdominal pain unrelieved by shifting or changing position can occur. Rupture is a grave event with 75% of patients not surviving despite best medical care. Here the pain is sudden, severe, unremitting and may be associated with temporary blackout or collapse. For this reason we recommend that they are repaired ‘cold’ i.e. prior to it bursting.
Diagnostic tests include a physical examination, imaging of the AAA with either CT, Ultrasound or Angiography. The fitness of the patient is also assessed with a focus on their heart, lung and kidney function.
If the shape of the AAA is not suitable for stent grafting then open surgery is recommended. This operation replaces the diseased or aneurysmal segment the Aorta with a synthetic Dacron graft – or knitted cloth tube. The abdomen is opened with a midline incision the Aorta and its branches are exposed and the graft is sewn onto the normal vessel above and below the AAA, effectively excluding it from the circulation. The graft may be a straight tube if the AAA only involves the Aorta. If the aneurysmal change extends beyond the Aorta into the iliacs arteries of the pelvis then a trouser shaped will be used.
The operation takes from 2 to 4½ hours. Patients will be transferred to the Intensive Care Unit post operatively for 1 to 2 days and be in hospital for 10 days.
Possible risks of surgery:
- All open aneurysm surgery is major and carries a risk of death – of between 1 and 5%.
- 20% of patients have a longer hospital stay than 10 days.
- Bleeding requiring transfusion occurs in 15% of cases. A cell saver which recycles the blood is routinely used with every case.
- Clots may form during the operation which can travel through the circulation and block vessels downstream in the legs or the gut arteries.
- 1 in 10 male patients may experience retrograde ejaculation. At the moment of orgasm the semen goes into the bladder rather than out the penis. A smaller number experience impotence.
- Temporary kidney failure which may require short term dialysis.
Information has been derived from the patient education pamphlet “Surgical Treatment of an Abdominal Aortic Aneurysm”, Royal Australian College of Surgeons and published by Mi-tec Medical Publishing. The complete pamphlet is available from our rooms.