Abdominal Aortic Aneurysm

As the aneurysm's diameter increases, the aorta wall grows increasingly weaker until even normal blood pressure can cause the artery to rupture, triggering severe internal bleeding.

Ruptured aneurysms are the third cause of cardiovascular disease mortality after heart attack and stroke, and were responsible for 6,358 deaths in 2008 in France, which is more than the number of deaths from road traffic accidents (source: INSERM).

There are three clinical presentations:

1. Asymptomatic aneurysms (majority of cases): patients have no symptoms indicating a possible abdominal aortic aneurysm.
2. Symptomatic aneurysms: patients feel abdominal pain of varying intensity and location, caused when the aneurysm grows or splits.
3. Ruptured aneurysms: this is a life-threatening emergency.

Given the absence of symptoms in most patients, aortic aneurysms are often detected during a routine medical exam, when a doctor sees or feels a pulse in the middle or lower abdomen. However, most aneurysms are discovered by chance during diagnostic imaging exams (CT scan, MRI or Doppler ultrasound) performed for other reasons.

Symptomatic aneurysms must be treated quickly as they carry a significant risk of rupturing. Because they can cause severe internal bleeding, a ruptured aneurysm requires emergency surgery.

It should be noted that 30% to 50% of smaller aortic aneurysms do not grow significantly and will not require intervention, as they present little to no risk of rupturing.

A Doppler ultrasound is the standard screening test. This non-invasive exam offers high levels of sensitivity and specificity.

Patients likely to undergo screening include:

• All men between the ages of 65 and 75, and all women in the same age group who smoke or previously smoked.
• All men and women over age 50 who have a family history of AAA

The risk of developing an abdominal aortic aneurysm increases with age. The condition mainly affects people 50 and over, and is more frequent in men than in women. Other risk factors include tobacco use and high blood pressure. Patients with a family history of AAA are more at risk and should discuss it with their doctor.

To prevent an abdominal aortic aneurysm, correcting certain risk factors is key, for example by giving up smoking or taking medication for hypertension.

If an aortic actasia (small dilation of the abdominal aorta) is detected during a diagnostic exam, an annual Doppler ultrasound exam will be recommended to monitor the dilated aorta. Sometimes an aortic CT angiogram is necessary.

Two treatment options are available for an abdominal aortic aneurysm:

1. Open repair

The surgeon makes an incision in the abdomen to access the aneurysm. A clamp is placed on either side of the aneurysm. The surgeon opens the aneurysm and removes the blood clots. The lumbar arteries that originate at the aneurysm site are sutured to prevent bleeding. Following the same principle as an arterial bypass, a synthetic tube-shaped or branched stent is then fastened to the healthy walls upstream and downstream from the aneurysm, in order to exclude the unhealthy section of the aorta and ensure blood supply to the lower limbs. The surgery is performed under general anesthesia and lasts two to three hours. Patients must generally spend one day in intensive care and remain in the hospital for at least one week. Two to three months may be necessary for a full recovery from the operation.

2. Endovascular aneurysm repair (EVAR)

This minimally invasive procedure is performed collaboratively by a vascular surgeon, an interventional radiologist and an anesthesiologist. It consists in placing a stent (made of metal or nitinol, a metal alloy with “shape memory” properties) covered by a leak-proof graft made of polyester fabric (Dacron) or PTFE (Teflon) inside the aorta. This technique requires no abdominal incision, and therefore leaves no abdominal scar. The stent graft is inserted through the femoral artery via an incision less than 15 millimeters long in the groin area, and delivered to the aortic aneurysm using x-ray guidance.

The operation is performed under local or general anesthesia in an angiography room or a hybrid room. It typically lasts 60 to 90 minutes, followed by a short hospital stay usually lasting three to five days. Patients do not necessarily spend any time in intensive care.

If a doctor diagnoses an abdominal aortic aneurysm, he or she will frequently check the diameter of the aneurysm, which is the main predictive criterion for treatment. Based on how quickly the aneurysm is growing and whether it has a “saccular” shape are also decision-making factors. France’s health authority, the Haute Autorité de Santé, recommends treatment when the aneurysm diameter exceeds 5 cm for men and 4.5 cm for women, or when growth exceeds 0.5 cm in a year.  

Stent grafts were invented approximately 35 years ago but only came into widespread use in the 1990s. They were initially used only on patients for whom surgery posed too many risks: patients with heart, respiratory or kidney failure, or having previously undergone abdominal surgery.

Today, the procedure is indicated for a much higher number of patients, provided their anatomy is suited to the operation.

The European Society of Vascular Surgery (ESVS) currently recommends stent grafting for:

• Patients with the appropriate anatomy and a reasonable life expectancy: endovascular aneurysm repair with insertion of a stent graft should be the first-line treatment (65 is considered as the reasonable threshold).
• For patients with a long life expectancy, aneurysm open repair should be the first-line treatment

The ESVS considers aortic surgery as a high-risk procedure, with a risk of death of cardiovascular origin or by myocardial infarction (heart attack) of 5% or higher in the 30 days following the operation. Mortality increases by up to 15% in patients presenting a high surgical risk due to cardiac, respiratory and renal co-morbidities. Open surgery on the aorta also has a 20% chance of causing abdominal eventration or intestinal obstruction caused by adhesions.