Introduction

A thoracic aortic aneurysm is a serious medical condition characterised by the abnormal dilation or bulging of the aorta in the chest area. The aorta, the largest artery in the human body, plays a critical role in carrying oxygenated blood from the heart to all organs and tissues. When this important vessel weakens and expands in the thoracic region, it poses a significant health risk. If left untreated, a thoracic aortic aneurysm can lead to aortic dissection or rupture, which are medical emergencies with potentially fatal consequences.1

The aorta originates from the left ventricle of the heart and courses through the chest cavity, supplying oxygen-rich blood to the upper body before continuing into the abdominal region. A thoracic aortic aneurysm specifically involves the section of the aorta within the chest and is distinct from an abdominal aortic aneurysm. Thoracic aortic aneurysms most frequently occur in the ascending aorta, the portion originating from the heart, or the descending thoracic aorta, the part located downstream from the aortic arch.2

The aorta: your body's main artery

The aorta is the human body's largest artery and is the primary conduit for oxygenated blood to flow from the heart to the rest of the body. It originates from the heart's left ventricle and spans the full length of the torso, extending from the chest cavity to the abdomen.

The aorta can be divided into five sections:

The aortic root, containing the aortic valve, connects directly to the left ventricle.

The ascending aorta continues upward from the aortic root before arching and turning downward.

The aortic arch branches into vessels supplying the head, neck, and arms.3

The descending thoracic aorta passes through the chest cavity.

The abdominal aorta supplies blood to the abdominal organs and legs.

On average, the aorta is 1 to 1.5 inches in diameter. This remarkable artery steadily tapers as it courses throughout the body, progressively branching into smaller arteries until finally dividing into the two iliac arteries that transport blood into each leg. The ascending aorta, aortic arch, and descending thoracic aorta comprise the thoracic section of the aorta inside the chest cavity. A thoracic aortic aneurysm specifically involves dilation of this thoracic portion of the aorta.

Types and causes

Thoracic aortic aneurysms are classified based on the segment of the aorta affected:

Ascending Aortic Aneurysm - An ascending aortic aneurysm occurs in the portion nearest the heart, including the aortic root, ascending aorta, and possibly extending into the arch. Ascending aortic aneurysms represent 60% of thoracic aortic aneurysms.4

Aortic Arch Aneurysm - The aortic arch branches to supply the head, neck, and arms. An arch aneurysm is located in this critical section of the aorta.

Descending Thoracic Aortic Aneurysm: - A descending thoracic aortic aneurysm, develops in the section downstream from the arch. This type accounts for approximately 40% of thoracic aneurysms.4

Several factors can predispose an individual to developing a thoracic aortic aneurysm:

Genetics - A family history of thoracic aortic aneurysms significantly increases risk. Genetic conditions like Marfan syndrome also raise risk.5

Hypertension - Chronic high blood pressure places increased force on the aortic wall and can cause weakening and dilation over time.6

Atherosclerosis - Fatty plaque buildup in the artery walls can weaken the aorta.

Age - Risk increases with age, with thoracic aortic aneurysms most common in those over 65.7

Sex - Those assigned male at birth (AMAB) have a higher prevalence of thoracic aortic aneurysms than those assigned female at birth (AFAB).7

Smoking - Tobacco use is a major preventable risk factor for aneurysm development.

Trauma - Physical trauma like motor vehicle collisions can injure the aorta and lead to aneurysm.

Signs and symptoms

Many thoracic aortic aneurysms remain asymptomatic and go undetected until they reach a significant size or begin to leak or rupture. When present, symptoms may include:

Chest pain - A constant, severe pain, pressure, or tightness in the chest that radiates to the back.

Shortness of breath - As the aneurysm enlarges, it can pressure the windpipe and lungs.

Coughing - Pressure on the windpipe can trigger chronic coughing.

Hoarseness - Compression of the vocal cords may cause voice hoarseness.

Swallowing difficulties - The oesophagus may be compressed, making swallowing painful.

Jaw pain - Aneurysms involving the ascending aorta can cause jaw discomfort.

Arm pain or weakness - Pressure on nerves can cause pain or weakness in one or both arms.

The onset of new chest or back pain in someone at risk warrants immediate medical evaluation, as it may signal a dissecting aneurysm. Seeking prompt emergency care is critical.

Getting diagnosed

If a thoracic aortic aneurysm is suspected based on risk factors or symptoms, diagnostic imaging is necessary to confirm diagnosis and determine treatment options.

Initial testing may involve:

Chest X-ray - Can detect aneurysms over 5 centimetres but lacks definitive detail.

Echocardiogram - Uses ultrasound waves to visualise the heart and nearby aorta.2

Further imaging for detailed evaluation includes:

CT angiogram - CT scanner generates 3D images of the aneurysm, aorta, and arteries.2

MRI angiogram - Provides 3D visualisation without radiation exposure.2

Aortogram - Contrast dye highlights the aorta via X-ray. This is a helpful evaluation pre-surgery.

Once diagnosed, regular monitoring is imperative. Imaging at six-month intervals allows assessment of the aneurysm's changes in size and shape and the risk of rupture.2

What can go wrong

If left untreated, a thoracic aortic aneurysm can progress and trigger life-threatening complications:

Aortic dissection - A tear in the artery allows blood to split the layers of the aortic wall apart. This causes severe chest and back pain and requires emergency surgery.1

Aneurysm rupture - As the aneurysm expands, the wall weakens until it ruptures completely, causing massive internal bleeding, ruptures have a high mortality rate.1

Heart failure - The aneurysm can compress heart structures or block blood flow from the heart into the aorta. this can lead to heart failure.2

Stroke - Dislodged aneurysm material can travel to the brain, blocking blood flow and causing a stroke.2

Organ damage - Reduced blood flow to organs like the kidneys due to aortic compression or blockage can lead to organ damage or failure.2

How to treat and manage

The approach for treating a thoracic aortic aneurysm depends on location, size, shape, presence of dissection, and patient health profile. Options may include:

Medications:

Beta-blockers to lower blood pressure and decrease the force on the weakened aorta.2

ACE inhibitors or ARBs relax blood vessels and reduce stress on the aortic wall.2

Pain relievers to manage aneurysm-related chest discomfort.

Surgery:

Endovascular stent graft - A catheter inserts a stent graft within the aneurysm to reinforce the aortic wall from further dilation. A minimally invasive option when suitable.2

Open surgical repair - Used for complex aneurysms, this invasive surgery grafts a Dacron tube to replace the damaged section of the aorta.2

Ascending aortic graft - The damaged section of the aortic root and ascending aorta is replaced with a Dacron graft.2

Conservative monitoring:

Smaller aneurysms may only require periodic CT scans, MRIs to monitor growth, and medications to control blood pressure.2

Preventing aneurysms

While some risk factors for thoracic aortic aneurysms, like genetics or age, are unavoidable, individuals can take proactive measures to reduce risk:

Maintain healthy blood pressure through diet, exercise, avoiding tobacco, and medication if needed. High blood pressure is a major modifiable risk factor.6

Take medications as prescribed to control high cholesterol or manage related conditions like atherosclerosis.

Exercise regularly to keep the cardiovascular system healthy.

Consume a heart-healthy diet emphasising fruits, vegetables, lean protein, whole grains, and healthy fats.

Avoid smoking and secondhand smoke exposure, a primary preventable cause of aneurysms.

Limit alcohol intake to moderate levels at most. Heavy alcohol consumption elevates blood pressure.

Follow annual checkup recommendations to monitor for early signs of aneurysm, especially if risk factors are present.7

Living with an aneurysm

Individuals diagnosed with a thoracic aortic aneurysm must adhere closely to their prescribed treatment plan and adapt certain lifestyle changes to promote aneurysm stability. Recommended tips for living with an aneurysm include:

Rigorously follow all medication instructions to control blood pressure or cholesterol.2

Refrain from strenuous weightlifting, contact sports, or intense physical exertion that could stress the aorta.

Maintain a healthy body weight through diet and light exercise like walking, yoga, or swimming. Obesity strains the cardiovascular system.6

Cease tobacco use completely, as smoking drastically accelerates aneurysm progression.1

Limit caffeine and stimulant intake that can spike blood pressure.6

Carry emergency medical ID denoting the aneurysm condition.1

Avoid activities causing abrupt straining, like heavy coughing or constipation.

Report any new or worsening symptoms promptly to your GP.2

Adhere to a regular schedule for continued imaging and monitoring appointments.2

Conclusion

Thoracic aortic aneurysms are serious vascular conditions requiring prompt diagnosis and ongoing management. Understanding the signs, symptoms, risk factors, and treatment options for thoracic aortic aneurysms empowers individuals to seek appropriate care and take preventive steps to maximise cardiovascular health. Advances in medical imaging now allow for earlier detection and monitoring of aneurysms while evolving surgical techniques and endovascular interventions dramatically improve outcomes.2 However, living with an aneurysm necessitates strict adherence to the prescribed treatment protocol and appropriate lifestyle adjustments.1 With comprehensive knowledge, vigilant monitoring, and proactive management, the potentially devastating consequences of thoracic aortic aneurysms can often be prevented.

Bibliography:

1. Ethan, M., Senser., Shantum, Misra., Stanislav, Henkin. Thoracic Aortic Aneurysm: A Clinical Review.. Cardiology Clinics, (2021). doi: 10.1016/J.CCL.2021.06.003
2. Eduardo, Díaz., HananAbdelmawgoud, Atia., Brian, Kohen., Seth, Lotterman. Thoracic Aortic Aneurysm Presenting as a Subacute Cough. POCUS journal, (2023). doi: 10.24908/pocus.v8i1.15894
3. Alison, Krywanczyk., E., Rene, Rodriguez., Carmela, D., Tan., Thomas, P., Gilson. Thoracic Aortic Aneurysm and Dissection. American Journal of Forensic Medicine and Pathology, (2023). doi: 10.1097/PAF.0000000000000819
4. Zainab, Faiza., Tariq, Sharman. Thoracic Aorta Aneurysm. (2020).
5. Yalchin, Efendiev., Elias, Jabbour. Thoracic Aortic Aneurysm and Dissection. (2023). doi: 10.1097/paf.0000000000000819
6. Ryan, Gouveia, e, Melo., Ryan, Gouveia, e, Melo., Gonçalo, S, Duarte., Gonçalo, S, Duarte., Alice, Casimiro, Lopes., Mariana, Alves., Daniel, Caldeira., Ruy, Fernandes, e, Fernandes., Luís, Mendes, Pedro. Incidence and Prevalence of Thoracic Aortic Aneurysms: A Systematic Review and Meta-analysis of Population-Based Studies.. Seminars in Thoracic and Cardiovascular Surgery, (2021). doi: 10.1053/J.SEMTCVS.2021.02.029
7. Maya, Salameh., James, H., Black., Elizabeth, V, Ratchford. Thoracic aortic aneurysm. Vascular Medicine, (2018). doi: 10.1177/1358863X18807760