Aortic Aneurysm vs Aortic Dissection: What’s the Difference?
An aortic aneurysm is an abnormal enlargement of the aorta. An aortic dissection is a tear in its inner lining that allows blood to separate the layers of the artery wall. They can occur separately or together. Both can be serious, but the diagnosis, urgency and treatment are different.
In this video, Dr Andrew Choong, vascular and endovascular surgeon in Singapore, explains why these terms matter when understanding an aortic diagnosis.
What is an aortic aneurysm?
The aorta is the body’s largest artery, carrying blood from the heart through the chest and abdomen. An aneurysm develops when part of it becomes abnormally enlarged, rather like a balloon.
An aneurysm in the abdomen is called an abdominal aortic aneurysm, or AAA. One in the chest is a thoracic aortic aneurysm. Some cause no symptoms and are found during imaging for another reason. The concern is that the weakened section may enlarge and eventually rupture. An aneurysm diagnosis does not, however, mean it has already burst.
What is an aortic dissection?
With a dissection, a tear in the inner lining allows blood to track between the layers of the aortic wall. This creates a second channel called a false lumen, alongside the original blood channel.
A dissection can disrupt blood flow to important organs and can lead to rupture. It requires a different assessment from simply measuring an enlarged aorta. Our aortic disease guide explains these conditions in more detail.
Can you have one without the other?
Yes. As the video explains, you can have an aneurysm without a dissection, and a dissection without an aneurysm. They can also coexist. A previously dissected aorta may enlarge over time, so follow-up remains important even after the initial event has been treated.
Rupture is another distinct term: it means blood escapes through the wall of the aorta. Neither “aneurysm” nor “dissection” automatically means rupture has occurred.
Why does the difference change treatment?
Aneurysm care
A stable aneurysm may be monitored with scans and treatment of relevant risk factors. Whether repair is appropriate depends on its location, size, growth, symptoms and the person’s overall health. Not every aneurysm needs an operation immediately.
Depending on the anatomy, options may include endovascular aneurysm repair (EVAR) for suitable abdominal aneurysms, thoracic endovascular aortic repair (TEVAR) for suitable disease in the chest, or open aortic surgery. These approaches are not interchangeable for every patient.
Dissection care
Suspected acute dissection needs urgent hospital assessment. A dissection involving the ascending aorta near the heart usually requires emergency surgery. Some uncomplicated dissections confined to the descending aorta are initially managed in hospital with medication and close monitoring; complications may require intervention. The scan findings and clinical situation determine the plan.
When should you seek emergency help?
Call 995 in Singapore for sudden severe chest, back or abdominal pain, particularly with collapse, breathlessness or sudden weakness. These symptoms may signal an aortic emergency or another life-threatening condition. Do not wait for a routine clinic appointment. Read more about aortic emergency awareness.
Who should discuss assessment or screening?
If you have a known aneurysm, previous dissection, a relevant family history or an abnormal scan, discuss an individual assessment and follow-up plan. Screening is based on risk; the video’s advice to seek assessment should not be taken to mean that everyone needs a scan.
For non-emergency concerns, contact Andrew Choong Vascular Surgery at Mount Elizabeth Novena Specialist Centre, Singapore. Bring any previous scan reports so the discussion can focus on your diagnosis and options. You can also watch the short explanation in the video library.