Thoracic Aortic Aneurysm (TAA) A Lady Killer?

Main Category: Vascular
Also Included In: Cardiovascular / Cardiology
Article Date: 23 Feb 2009 - 4:00 PDT

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Thoracic aortic aneurysm (TAA) is a serious health condition that often affects older patients, and is one to which women should pay extra attention. This article will explain what a thoracic aneurysm is, the symptoms to look out for, and what your treatment options are if you suffer from this condition.

What is a thoracic aneurysm?

TAAs occur in the aorta, the main blood vessel that carries blood from the heart to the rest of the body. The aorta extends from the chest to the abdomen, where it branches into the iliac arteries, which carry blood to the legs. Sometimes, due to old age or as a result of other heart conditions, a section of the aorta may weaken and begin to bulge. This bulge can enlarge over time as the walls of the aorta become thinner and stretch (like a balloon). This bulge in the aorta is called an aneurysm. If an aneurysm occurs in the part of the aorta that runs through the chest, it is known as a thoracic aortic aneurysm (TAA).

A small TAA may not pose any immediate risks to a person's overall health. But if it continues to grow, the walls of the aorta can become thin and stretch out of shape. These weakened sections of the aortic wall may eventually be unable to support the force of blood flow and burst, causing serious internal bleeding. And patients whose aneurysm ruptures are very likely to die as a result of the rupture.

One for the ladies

Aneurysms are often thought of as a male disease but studies have shown that women are nearly as likely as men to suffer from a TAA. The female-to-male incidence rate of TAA (40 per cent female to 60 per cent male) is higher than it is for abdominal aortic aneurysms (AAA), which occur lower down in the body. In addition, early symptoms for TAA may be less noticeable to the patient than AAA.

Consequently, women need to be extra vigilant about this condition because, as a result of their physiology, their aneurysms are more likely to rupture than those in male patients: a US study showed that 79 per cent of ruptured TAA cases were female patients.

The current situation

Unfortunately, there are no plans to screen women or men routinely for TAA as the condition requires more advanced - and expensive - scanning and imaging technologies to diagnose. Unlike AAA, which requires a simple ultrasound scan to be detected, procedures such as MRI or CT scans are needed to diagnose TAA.

Detection is made even more difficult because most people with a TAA have few definable symptoms. If a TAA is sufficiently developed, symptoms can range from back and chest pain to breathing or swallowing difficulties and a hoarse cough. However, these complaints are easily attributed to other conditions, especially in older patients.

Most at risk of developing a thoracic aneurysm are women and men over the age of 65, particularly those who have a family history of heart conditions and/or aneurysms, and those with a history of smoking. If you fall into these categories, you should be aware of the danger of TAAs.

Treatment options

If an aneurysm is discovered, and at risk of rupturing, medical intervention is needed to stop it from bursting. In the past, TAAs could only be repaired via open chest surgery. This is a long and traumatic operation that opens the chest cavity, requiring general anaesthetic and clamping off the aorta above and blow the diseased section, which is cut out and replaced with a synthetic graft. The surgical trauma was often too much for older patients to bear, and even if the surgery could be performed, it required lengthy post-surgical hospitalisation, and long recovery times before resuming normal activities.

To address those concerns and offer treatment to patients who otherwise could not have been helped, interventional physicians have developed an alternative called endovascular aneurysm repair (EVAR). Instead of opening the chest, EVAR is a minimally invasive procedure in which a small incision is made in the groin area. A stent-graft is then inserted through these cuts into the femoral arteries in the leg. Surgeons guide the stent-graft into the main aorta, where it is deployed from a delivery system and expanded in place to seal off the aneurysm and provide a new channel for blood flow that reduces pressure on the aneurysmal sac to reduce the risk of rupture.

People undergoing EVAR only need an epidural, rather than general anaesthetic, meaning that they are awake throughout the operation. This, combined with the minimally invasive technique, makes the procedure less traumatic and has a shorter recovery period with less likelihood of time spent in intensive care. However, take up of EVAR has been slow: the majority of UK aneurysm repairs are still carried out using open surgical techniques.

Case study: Elizabeth Ferguson

Elizabeth Ferguson did not show any of the usual symptoms associated with TAA, but in December 2005 as she was shopping with her husband, she lost power and control of both her legs and was feeling dreadful pain in her back. Just before her shopping trip, Elizabeth had picked up a prescription at the doctors as she was feeling under the weather with cold or flu-like symptoms and pain in her abdomen. After the shopping episode, Elizabeth went back to the doctors and explained what had happened.

At the surgery the doctor diagnosed pneumonia and Elizabeth was prescribed antibiotics and was sent home to rest and recuperate. Elizabeth had experienced a bout of pneumonia in the 1960s and did not believe the pain in her abdomen was related. She went to the hospital, had an x-ray and was given more antibiotics to fight the infection.

When the second set of antibiotics didn't work, Elizabeth was admitted to the NHS Lothian, Royal Infirmary of Edinburgh, and after a CAT scan was diagnosed with a large 8cm thoracic aneurysm. Without surgery, Elizabeth was told she had five months to live. The operation took place in May 2006 and Elizabeth has since recovered very well.

Elizabeth's aneurysm posed a significant risk to her life. Additionally, as she had been suffering from a chest complaint, placing a stent via her groin was considered the safest option.

Her consultant, Mr Rod Chalmers, one of the UK's leading endovascular consultants, at the Royal Infirmary, Edinburgh, replaced the aorta with an aorto-bifemoral bypass. An aorto-bifemoral bypass is a type of surgery in which the diseased aorto-iliac arteries are replaced with synthetic tubes (grafts) made of special cloth. The material is manufactured to resemble a pair of pants; the waist is sewn to a healthy part of the aorta, and the legs are sewn to the femoral arteries in each groin, so that blood flows freely through the graft, bypassing the patient's blocked arteries.

Once the bifemoral graft was in place, Mr Chalmers gained access to Elizabeth's two thoracic aneurysms. He used a custom-made Cook Medical stent-graft designed specifically to fit Elizabeth's aorta. Elizabeth would have been exposed to massive risk if she had been treated by way of conventional open surgery.

Written by Phil Nowell, Cook Medical's Aortic Intervention Global Leader

Cook Medical