WHAT DOES ANEURYSM MEAN ?
An aneurysm is a bulge in a portion of an artery. It is due to weakness in the wall of the blood vessel and the wall of the artery is overstretched. Large aneurysms can burst and cause serious internal bleeding that lead to death, that is why prevention is a major issue.
COMMON LOCATIONS :
1. Aorta : The aorta is the body’s main artery that supplies blood from the heart to the rest of the body. Aneurysms can form in any portion of the aorta, but they are most common in the abdomen.
a. Aneurysm of the abdominal aorta (Abdominal Aortic Aneurysm – AAA) : It is located in the part of the aorta that supplies blood to the abdomen, pelvis and lower limbs.
b. Aneurysm of the thoracic aorta : It is located in the upper body
2. Iliac artery
3. Popliteal artery : located in the leg, behind the knee
4. Cerebral artery : located in the brain
5. Mesenteric artery : located in the abdomen (intestine)
6. Spleenic artery : in the abdomen (spleen)
ABDOMINAL AORTIC ANEURYSM (AAA) :
1. WHAT ARE THE RISK FACTORS ?
AAA is a multifactorial disease. The exact mechanisms are not well defined yet but there are well-known risk factors for developing AAA :
a. Age (> 60 yo)
b. Genetic factors
c. Male gender
d. High blood pressure
f. High cholesterol
In fact, AAA is most often seen in males over 60 years who have one or more risk factors.
In rare cases AAA can be due to inflammation of the aorta :
a. Idiopathic (unknown cause) inflammatory AAA : Imaging techniques (ultrasounds, CT-scan or MRI) show a thickened aortic wall and retroperitonal fibrosis (fibrosis around the aorta). It is an immunitary disease with abdominal pain, weight loss and sometimes urinary symptoms and lower limb edema. Corticoids are recommended and sometimes surgery when the inflammatory process is under control.
b. Extensive inflammation of the arteries (arteritis) : Giant cell arteritis, Takayasu disease, Behçet disease…
c. Infection : Infectious aortitis is rare. It can be due to local infection or to infection of a heart valve (endocarditis). Other causes are syphilis, tuberculosis. Specific antibiotic treatment is mandatory.
Genetic diseases of the connective tissue, such as Ehlers-Danlos or Marfan disease, can also cause AAA.
2. WHAT ARE THE SYMPTOMS OF AAA ?
Usually AAAs develop slowly over many years without symptoms. Large AAAs are more prone to rupture. The symptoms of rupture include :
a. Pain in the abdomen or back (severe, sudden, persistent, or constant pain). The pain may spread to the groin, buttocks, or legs
b. Clammy skin
d. Shock with very low blood pressure and rapid heart rate.
The risk of death after a rupture is high. Suspicion of AAA rupture is an emergency!
Slow blood flow in the bulging portion of the artery causes clots to form. Blood clots can break off and migrate to the brain (thoracic aortic aneurysm), to the legs (AAA) or the feet (AAA, popliteal aneurysm) and stop blood flow distally (emboli).
3. DIAGNOSTIC TOOLS :
a. Physical exam : Your doctor may find a pulsating mass in your abdomen
b. Ultrasound of the abdomen
c. CT scan of the abdomen
4. TREATMENT :
a. Prevention of rupture : The goal is to perform surgery before complications when the risk of having surgery is smaller than the risk of rupture without surgery. If your AAA is small and if you don’t have symptoms, the risk of rupture is slow and your doctor will prescribe medical treatment and recommend routine ultrasound tests to see if the AAA is getting bigger. Because large AAAs grow more quickly than small ones, the frequency of check-ups depends on the size of the AAA.
Surgery is usually recommended for AAA diameter > 55 mm or in case of quick growth. There are 2 different approaches to surgery :
i. The open repair : It involves a large incision of the abdomen. It is performed under general anesthesia. The abnormal vessel is replaced with a long cylinder-like tube called a graft. Prosthetic grafts are made of different materials, such as Dacron. The graft is sutured to the aorta connecting one end of the aorta at the site of the aneurysm to the other end of the aorta. In case of aortoiliac aneurysm a Y shaped graft is used to replace the aortoiliac aneurysm.
ii. The endovascular aneurysm repair (EVAR) : It is a minimally-invasive procedure. EVAR may be performed under general anesthesia or regional anesthesia (epidural or spinal anesthesia) in an operating room, radiology department, or a catheterization laboratory. The doctor makes a small incision in each groin. With X-ray images for guidance, a stent-graft is inserted through the femoral artery and advanced up into the aorta to the site of the aneurysm. A stent-graft is a long cylinder-like tube made of a thin metal framework (stent) that reinforces the aortic wall, while the graft portion is made of various materials such as Dacron or polytetrafluoroethylene (PTFE) that cover the stent. The stent helps to hold the graft in place. Once in place, the stent-graft is expanded. The aneurysm will eventually shrink down onto the stent-graft. There is no cut in the abdomen, so the patient may get well faster. Unfortunately not all patients are candidates for stenting depending mostly on the morphology of their AAA.
b. In case of rupture and internal bleeding : rupture requires immediate open abdominal repair. Endovascular stent grafting can rarely be performed in case of rupture.
5. OUTLOOK (PROGNOSIS) :
If the AAA is repaired before rupture the outcome is usually good. Rupture is a true emergency. Less than 80% of patients survive a ruptured AAA.
6. PREVENTION AND MEDICAL TREATMENT :
a. Eat a heart-healthy diet
c. Stop smoking : quitting will lower your risk of an AAA and slow its growth !
d. Reduce stress
e. Check your blood pressure. If you have hypertension, take your pills regularly as your doctor has asked you to
f. If your doctor has given you medicine to lower your cholesterol (statins), to fluidify your blood (aspirin or other anti-platelet drugs), to treat your diabetes, take them as you have been told.
g. Don’t forget that if you have an AAA, you may be at risk for heart problems. Coronary heart disease screening and cardiovascular risk factors control are recommended.
h. Some drugs are supposed to slow the growth of the AAA : statins, beta-blockers, ACE-inhibitors. Your doctor may choose to prescribe them.
i. Antiplatelet drugs, especially aspirin, reduce the risk of clot migration
7. SCREENING :
AAA are often found by chance during tests (ultrasounds, CT-scan or MRI) done for other reasons (abdominal pain, back pain…).
Sometimes they are diagnosed thanks to screening. Screening is recommended for :
a. people over 50 that have a first-degree relative (eg father or brother) who has had an aneurysm
b. people over 65 (esp men) who have smoked at any time in their life
Screening is advised for :
a. men over 60 who have never smoked
c. women over 60 who have smoked at any time in their life and/or have high blood pressure (even if treated)
Screening for people over 75 is advised if life expectancy is not too bad