Abdominal Aortic Aneurysm Surgery: Indications and Risks

Aneurysms are abnormally dilated blood vessels. Aortic abdominal aneurysms are abnormal dilatation of the descending aorta, the largest blood vessel in the abdomen. These aneurysms are generally asymptomatic. When symptomatic the aneurysm may manifest with back pain or pulsation around the navel or constant pain in the abdomen. Various surgical procedures are available to correct abdominal aortic aneurysm (AAA).

Types of Abdominal Aortic Aneurysm Surgery

Open aneurysm repair: under general anesthesia, the abdomen is opened and the affected part of the aorta is identified and clamped shut on both ends. The aneurysm sac is then opened longitudinally and a synthetic tube is introduced inside it which will replace the diseased portion of the aorta. This synthetic tube is sewed with the healthy ends of the aorta and the diseased portion is used to cover up the synthetic tube.

Endovascular aneurysm repair (EVAR): It less invasive compared to open aneurysm repair. In this procedure, your doctor will put a thin tube (catheters) through your femoral artery (artery present in the groin). Through this tube, an angiogram is done to identify the location of the aneurysm. A graft, made of synthetic material reinforced with a metal mesh, is introduced into the aneurysm sac and expanded. The graft is also fitted with small hooks or barbs to anchor it to the wall of the vessel. The graft is generally in two are three parts, a main body that is placed in the aorta and two limbs that connect it to the major arteries which supply blood to the pelvis and the limbs.

Indications of Abdominal Aortic Aneurysm Surgery

Most of the AAA are asymptomatic and are often identified during routine health checkups. Although all aneurysms can cause symptoms the ones which are twice the size of the corresponding normal vessel are at an increased risk of complication, like rupture of an AAA which is a medical emergency.

Hence an otherwise healthy individual with an AAA which is more than 55mm in diameter is considered for repair.

Currently, most of the AAA is repaired by Endovascular repair because of the reduced mortality risk and faster recovery time that accompany the procedure. Some individuals have a condition which makes access to the arteries by a catheter difficult, open aneurysm repair is the suggested method to reduce the risk for further complications.

Complications of  Abdominal Aortic Aneurysm Surgery

Open Aneurysm Repair

• The most common complications are cardiac ischemia (reduced blood flow to the heart leading to damage to the heart muscles) and respiratory complications.
• Colonic ischemia (reduced blood flow to the bowel) occurs in about 10% of the patients. It resolves on its own in most individuals.
• Sexual dysfunction is seen in a small proportion of individuals
• Tar colored smelly stool or blood in vomit, few months or years after the surgery. This is an uncommon but treatable complication caused due to a connection formed between the gut and the aorta.
• The infection of the graft is an uncommon complication, which can be corrected by replacing the synthetic graft with a blood vessel from the body of the affected individual.

Evar

• This procedure reduces the risk which commonly accompanies open aneurysm repair, but it comes with its own set of complication.
• Endoleak: when the graft is not sealed properly at the two ends of the aneurysm sac, the blood keeps on circulating in an aneurysm and causes it to grow which may eventually lead to a rupture.
• Local complication like a blood clot or infection, where catheters were introduced are seen in 1-10% of individuals
• Misplacement of the graft which might interrupt blood supply to the kidney. Some of the affected individuals may have to be on dialysis for their life.
• Infection of graft leading to fever and back pain.

Recovery

The recovery period for open aneurysm repair is about a month while that for EVAR is nearly 2 weeks. Following an open aneurysm repair your doctor will advise you to avoid bearing down and strenuous activities for a few days. You will be advised to keep the wound clean with the help of mild soap and water and to ensure that the wound is dry. If you have undergone an EVAR, you will be required to have a lifelong follow up with CT scans to detect Endoleak and to check that the graft is in a proper place.

Resources:

• The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm.