Difference Between True and False Aneurysm

The key difference between true and false aneurysm is that a true aneurysm is an enlargement of all three layers of the wall of an artery while a false aneurysm or pseudoaneurysm is not an enlargement of any layers of the blood vessel wall.

Aneurysm is the bulging of the wall of a blood vessel, resulting in the formation of bulges or balloons. It happens due to a weak point in the vessels wall. Generally, aneurysms are common in arteries than in veins. When the aneurysm increases in the size, the probability of rupturing the blood vessel increases. If an artery ruptures, it causes an uncontrolled blood leaking. Aneurysm differs from morphology, cause and location. There are two types of aneurysms. They are true and false aneurysm. True aneurysm involves all three layers of the wall of an artery, but, false aneurysm is not an enlargement of any layers of the artery wall.

1. Overview and Key Difference
2. What is True Aneurysm
3. What is False Aneurysm
4. Similarities Between True and False Aneurysm
5. Side by Side Comparison – True vs False Aneurysm in Tabular Form
6. Summary

What is True Aneurysm?

True aneurysm is a bulging or enlargement of all three layers of the wall of an artery. It is an abnormal dilation of an artery due to a weakened artery wall. True aneurysm is most frequently a consequence of atherosclerosis. It can also be caused due to hypertension, vasculitis, congenital, myocardial infarction and syphilis, etc. Generally, true aneurysms are fusiform or saccular in shape. Fusiform-shaped aneurysm bulges or balloons out on all sides of the blood vessel. A saccular-shaped aneurysm bulges or balloons out only on one side.

Difference Between True and False Aneurysm

Figure 01: True Aneurysm

What is False Aneurysm?

False aneurysm is a collection of blood leaked from an artery. It is a blood-filled cavity between the vessel and the surrounding tissue. It is not an enlargement of any layer of the wall of an artery. Hence, it is an external hematoma. This false aneurysm may clot or rupture out of the surrounding tissue. False aneurysm is a result of trauma or iatrogenic. It can also be due to spontaneous dissection, fibromuscular dysplasia, mycotic aneurysm, vessel injury, etc.

Figure 02: False Aneurysm

The risk of rupturing a false aneurysm is higher than that of a true aneurysm. This is because false aneurysm has poor support from the aneurysm wall. Hence, false aneurysm requires treatment. Surgery is one treatment, while there are several less invasive treatment options.

What are the Similarities Between True and False Aneurysm?

True and false aneurysms are two types of aneurysms.
Both cause the rupturing of blood vessels.
When the size of aneurysm increases, the risk rupturing it also increases.
Both true and false aneurysms can be complications of myocardial infarction.

What is the Difference Between True and False Aneurysm?

True aneurysm is an abnormal dilation of an artery involving all three layers of the artery wall. In contrast, false aneurysm is a collection of blood leaked outside the normal layers of an artery. True aneurysm involves all layers of the artery wall while false aneurysm does not. So, this is the key difference between true and false aneurysm. Moreover, the risk of rupture is higher in false aneurysm than a true aneurysm.

The below infographic summarizes the difference between true and false aneurysm.

Summary – True vs False Aneurysm

Aneurysm is a bulging of a blood vessel. It causes an abnormal widening or ballooning in the blood vessel compared to normal size. True and false aneurysms are two types. The wall of a true aneurysm maintains the normal three-layered structure of an artery (intima, media, adventitia), while a false aneurysm does not involve all three layers of the artery wall. So, this is the key difference between true and false aneurysm. Moreover, atherosclerosis is the most common aetiology of a true aneurysm while trauma is the most common aetiology of a false aneurysm.

Reference:

1. “Aneurysm.” Wikipedia, Wikimedia Foundation, 25 Aug. 2020, Available here.

Image Courtesy:

1. “Thoracic Aortic Aneurysm” By BruceBlaus – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Heart pseudoaneurysm a4c” By Patrick J. Lynch, medical illustrator – Patrick J. Lynch, medical illustrator (CC BY 2.5) via Commons Wikimedia