Aortic Aneurysm

An aortic aneurysm is a localized or diffuse enlargement of the aorta involving all three layers of the aortic wall. Most aneurysms are caused by atherosclerosis, while trauma, infections and genetic syndromes are other causes[1].

Aortic aneurysms can occur along the entire length of the aorta, but they are most common in the lower part. This is called an abdominal aortic aneurysm. When they occur in the upper part of the aorta, in the chest, they are called thoracic aortic aneurysms.

The enlargement of the aorta occurs when part of the blood vessel becomes weakened and expands under pressure. Aneurysms usually start small and grow larger as pressure increases. They generally grow very slowly.

Sometimes aneurysms can rupture and cause internal bleeding. Because the aorta is such a large blood vessel, this can be extremely dangerous and is often fatal[2].

Illustration: Aortic Aneurysm.

Risk Factors

You may have an increased risk of developing an aortic aneurysm because of:

1. Age - The risk of aortic aneurysms increases with age. Abdominal aortic aneurysms are most common in adults over 65 years of age.

2. Family history and genetics - Several familial or genetic conditions increase the risk of thoracic aortic aneurysm. These include:

   • Ehlers–Danlos syndrome

   • Loeys–Dietz syndrome

   • Marfan syndrome

   • Turner syndrome

   • Familial thoracic aortic aneurysm

   • Bicuspid aortic valve (BAV), which is an abnormal aortic valve

   • Abdominal aortic aneurysm can also run in families.

3. Lifestyle factors - Some lifestyle factors increase the risk of aortic aneurysm. These include:

   • Smoking

   • Use of stimulants, such as cocaine

   • Weightlifting

4. Medical conditions - Medical conditions that are risk factors for aortic aneurysms include:

   • Aneurysms in blood vessels elsewhere in the body

   • Chronic obstructive pulmonary disease (COPD)

   • Cardiovascular disease, such as atherosclerosis, coronary artery disease and peripheral arterial disease

   • High cholesterol

   • Hypertension

   • Infection, a risk factor for thoracic aortic aneurysms

   • Kidney disease, such as chronic kidney failure and polycystic kidney disease

   • Obesity

   • Pheochromocytoma, a rare adrenal tumor that can cause high blood pressure

   • Trauma, such as motor vehicle accidents or falls

   • Vasculitis

   • Sex - Men are more likely than women to develop aortic aneurysms. However, an existing aneurysm is more likely to rupture at a smaller size in women than in men[3].

Clinical Presentation

An aortic aneurysm may not cause any signs or symptoms until the aneurysm ruptures or dissects. Symptoms that occur before rupture depend on where the aneurysm is located and whether it has become large enough to affect other parts of the body.

Symptoms of an aneurysm that ruptures or dissects are life-threatening. Signs of a possible aortic aneurysm in the chest include:

• Chest or back pain

• Difficulty swallowing

• Difficulty breathing

• Cough or hoarseness

If the aneurysm is in the abdomen, signs may include:

• Back pain (Note: Low back pain is most commonly caused by mechanical dysfunction, but 1–2% of cases of low back pain may be caused by non-mechanical spinal disorders or visceral disease such as an abdominal aortic aneurysm)[4]

• Deep pain in the side of the abdomen

• A pulsating sensation near the navel[2]

Diagnosis

Aortic aneurysms are often discovered when people seek medical attention for another problem, such as prostate problems or gallstones[2].

Different types of imaging can be used to diagnose an aortic aneurysm. A doctor may order one or more of the following imaging tests to confirm or diagnose an aortic aneurysm:

• Computed tomography (CT) to provide information about the location, size and shape of the aneurysm.

• Echocardiography to provide information about the size of the aortic aneurysm and the thoracic aorta near the heart.

• MRI (magnetic resonance imaging) to provide information about the size, shape and location of the aneurysm.

• Ultrasound to provide information about the size of an abdominal aortic aneurysm. In cases of abdominal or back pain, ultrasound may be used to check for an abdominal aortic aneurysm or other possible causes of the pain[3].

Treatment

Small aneurysms less than 5.5 cm in diameter usually do not require surgical treatment. This can be a frightening diagnosis and should be taken seriously, but in many patients these aneurysms have been growing for several years. It is important to remain calm, avoid extreme stress and attend regular follow-up appointments[5].

Aneurysms larger than 5.5 cm in diameter are more likely to require surgery because they have a higher risk of rupture. Surgery may also be considered if a smaller aneurysm is growing rapidly or causing other problems.

Until relatively recently, the only treatment for aortic aneurysm was open surgery, a major procedure in which the affected part of the aorta is replaced with an artificial blood vessel. Patients usually remain in hospital for 7 to 10 days and may spend time in an intensive care unit.

Some people can have a stent inserted into the aneurysm through small incisions in the groin to reinforce the aortic wall (endovascular surgery). This is not suitable for every type of aortic aneurysm. Another option is minimally invasive repair of the aortic aneurysm[2].

Prevention

It is not always possible to prevent an aortic aneurysm, but it may be possible to reduce the risk of further growth. People with an aortic aneurysm should stop smoking and follow medical advice regarding blood-pressure control and treatment of atherosclerosis.

Illustration: Aortic Aneurysm.

Physiotherapy Management

Remember - Aortic aneurysm is an important red flag to consider in patients presenting with low back pain[6].

There is currently no conservative treatment that can reverse the progression of an aortic aneurysm, but a physiotherapist can provide education on reducing risk factors, for example:

• Avoid stimulants such as cocaine

• Follow a heart-healthy diet

• Manage stress, which may help reduce high blood pressure

• Stop smoking, particularly cigarette smoking, which is a major risk factor for the development of aortic aneurysm[3]

• Reduce cardiovascular risk factors and improve cardiovascular fitness through appropriate exercise such as treadmill walking, cycle ergometry, stair climbing or elliptical training

Preoperative physiotherapy has also shown promising effects in reducing the risk of complications after aortic aneurysm surgery, although the reasons remain uncertain and further research is needed.

Physiotherapy for postoperative patients should focus on inspection of the incision site and bronchial-hygiene techniques to reduce the incidence of pulmonary complications[7].

Although an exercise test is usually not required before starting a low-intensity exercise program (<40% of heart-rate reserve or VO2 peak), such as walking, medical clearance is advisable before engaging in moderate-intensity (40–59%) or high-intensity (≥60%) exercise such as brisk walking or jogging. This may include completion of an exercise stress test.

Cardiac rehabilitation (CR) programs have expanded their referral base in recent years to include patients beyond those with coronary artery disease. Patients with concurrent AAA or TAA, diagnosed or undiagnosed, may participate in CR to an unknown extent. Patients with isolated small AAA or TAA may be suitable candidates for CR programs[8].

Sources:

1. Radiopaedia Aortic Aneurysm : https://radiopaedia.org/articles/aortic-aneurysm-1

2. Healthdirect Aortic Aneurysm :https://www.healthdirect.gov.au/aortic-aneurysm

3. NIH Aortic Aneurysm : https://www.nhlbi.nih.gov/health-topics/aneurysm

4. https://www.physio-pedia.com/Low_Back_Pain_or_a_silent_killer_(AAA)-_A_case_Study?utm_source=physiopedia&utm_medium=related_articles&utm_campaign=ongoing_internal

5. Heart Valve Surgery Surgeon Q&A: Top 6 Facts About Aortic Aneurysms & Heart Valve Disease :https://www.heart-valve-surgery.com/heart-surgery-blog/2017/09/28/top-facts-aortic-aneurysms-eric-weiss-dr/

6. SlideShare Aortic aneurysm and low back pain ... The forgotten red flag : https://www.slideshare.net/TaylorAlanJ/aortic-aneurysm-and-low-back-pain

7. Physiopedia Abdominal Aortic Aneurysm : Abdominal Aortic Aneurysm

8. Ehrman JK, Fernandez AB, Myers J, Oh P, Thompson PD, Keteyian SJ. Aortic Aneurysm: Diagnosis, management, exercise testing and training Journal of Cardiopulmonary Rehabilitation and Prevention. 2020 Jul 1;40(4):215-23.: https://journals.lww.com/jcrjournal/Fulltext/2020/07000/Aortic_Aneurysm__DIAGNOSIS,_MANAGEMENT,_EXERCISE.3.aspx