Abdominal Aortic Aneurysm

What is an abdominal aortic aneurysm(AAA)?

An Abdominal Aortic Aneurysm(AAA or Triple A) is a widening, ballooning or dilatation of a part of the abdominal aorta.

  • Who is most likely to have an abdominal aortic aneurysm?
  • What is the treatment?
  • Complications
  • What happens in ICU?
  • How long will your loved one remain in ICU?
  • Internet Links

 

The aorta is a large blood vessel which carries blood, rich in oxygen from the heart to every part of the body. It passes from the heart through the chest area and then down through the abdominal area. Around the navel (bellybutton) it branches into two smaller vessels to supply the legs. This section of aorta in the abdomen is called the abdominal aorta.

Abdominal aortic aneurysm (also known as AAA, pronounced “triple-a”) is a localized dilatation (ballooning) of the abdominal aorta exceeding the normal diameter by more than 50 percent, and is the most common form of aortic aneurysm. Approximately 90 percent of abdominal aortic aneurysms occur below the kidneys, but they can also occur at the level of the kidneys or above the kidneys.

An abdominal aortic aneurysm is a widening or dilatation(ballooning) of a part of the abdominal aorta. Usually it is most common secondary to a hardening or calcification of the arteries (arteriosclerosis) which causes an area of the wall of the aorta to weaken or soften. The blood pressure of the blood being pumped through the aorta causes the weakened area to bulge into an aneurysm. Many people with an abdominal aortic aneurysm have no symptoms or at least have no symptoms for a long time and it is often only discovered while having investigations done for other reasons.

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Who is most likely to have an abdominal aortic aneurysm

Abdominal aortic aneurysms occur most commonly in individuals between 65 and 75 years old and are more common among men and smokers. They tend to cause no symptoms, although occasionally they cause pain in the abdomen and back (due to pressure on surrounding tissues) or in the legs (due to disturbed blood flow). The major complication of abdominal aortic aneurysms is rupture, which is life-threatening, as large amounts of blood spill into the abdominal cavity, and can lead to death within minutes.Mortality of rupture repair in the hospital is 60% to 90%. High blood pressure, diabetes, high blood cholesterol level and smoking are usually causes that may lead to an Aortic Abdominal Aneurysm.

Abdominal aortic aneurysm treatment

Abdominal aortic aneurysms which have no symptoms and are 5cms or less in width do not require surgery. They are monitored every 6 to 12 months by scanning (ultrasound) the abdomen and high blood pressure is controlled with medication. Smoking is discouraged. Some patients who are young and healthy may decide to have surgery for aneurysms between 4 and 5cms. Aneurysms will usually require surgery if they are larger than 5cm, getting larger or causing symptoms.

There are two main methods of repairing a AAA: the open approach and a stent graft. When the patient has an open operation the area of aorta affected by the aneurysm is cut open and a tube of synthetic material inserted to provide a safe channel for the blood to flow through. The aneurysm is then sewn around the synthetic material.

These days the aneurysm can in some cases be repaired by a method called a “stent graft” or Endoluminal/Endovascular AAA repair. This is a procedure that does not involve the abdomen being opened and it is similar to approaches used when performing an Angiogram. Instead the aneurysm is reached by a thin tube (catheter) passed into a blood vessel through a small cut made in the groin through the femoral artery. Attached to the catheter is a long capsule containing a tube of synthetic material encased in a collapsed metal-mesh cylinder. When the catheter reaches the area of the aneurysm the stent is “opened” and attaches itself to the wall of the aorta. The synthetic tube now provides a passage for blood flow, whilst sealing the Aneurysm and not causing anymore pressure to the widening of the Aorta.

Patients undergoing the ‘Endoluminal/Endovascular AAA repair’ or the ‘stent graft AAA repair’ tend to stay in hospital fewer days compared to Patients undergoing the traditional surgical approach(open AAA repair).

What are the complications of an abdominal aortic aneurysm?

Large abdominal aortic aneurysms can cause a rupture of the Aneurysm . The Patient is usually bleeding heavily and quickly goes into hypovolaemic shock caused by massive fluid loss because of the bleeding. The death or mortality rate is by around 50%.

Another risk factor, when being diagnosed with an Aneurysm is that blood clots(Thrombosis) can occur in the Aneurysm and after a while a piece can break off and get stuck in the smaller blood vessels in the legs. This blocks blood supply beyond this point and urgent treatment in hospital is required to stop the tissue in the leg from dying.This is also known as DVT or ‘Deep vein Thrombosis’.

What happens in Intensive Care?

  • Your loved one is continuously monitored with a Bedside Monitors-  Your loved ones Blood pressure is usually displayed continuously on the bedside monitor via an Arterial Catheter. Your loved ones Heart and Heart rhythm(ECG) is continuously monitored and displayed on the monitor. Oxygen levels are continuously monitored by an oxygen saturation probe attached to the finger or to the ear. Furthermore oxygen levels are intermittently checked with ABG’s(Arterial Blood Gases), where blood is drawn out of the Arterial line and tested immediately via a Blood Gas Analyser.
  • Drugs for blood pressure control are often administered as an infusion via an infusion pump. This allows for strict blood pressure control. Once your loved one is fully awake and able to swallow blood pressure tablets may also be given.
  • Blood perfusion to the legs are assessed regularly to observe for adequate blood flow to the area.
  • Urine output is monitored via a tube (catheter) in the bladder to assess kidney function and monitor and manage fluid balance.
  • Pain relief is provided as necessary.
  • Your loved one may be ventilated via a Breathing Tube  with a Ventilator (Breathing Machine)

How long will my loved one remain in Intensive Care?

Generally your loved one needs to stay in the Intensive Care Unit for one or two days following repair of an abdominal aortic aneurysm, if the procedure goes as planned. The stay following repair of a ruptured aortic aneurysm however is considerably longer and generally many surgical abdominal aortic aneurysm repairs tend to stay for up to 5-7 days in Intensive Care.

Internet Links

Any Questions?

Of course, if you have any questions or concerns, please discuss them with the ICU nurses and doctors.

All Intensive Care interventions and procedures carry a degree of potential risk even when performed by skilled and experienced staff. Please discuss these issues with the medical and nursing staff who are caring for your loved one.

The information contained on this page is general in nature and therefore cannot reflect individual Patient variation. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. INTENSIVE CARE HOTLINE attests to the accuracy of the information contained here BUT takes no responsibility for how it may apply to an individual Patient. Please refer to the full disclaimer.

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