1. C32 Surviving an Abdominal Aortic Aneurysm
Waert student symposium 2018

2. Objectives: Define an aneurysm Explain the different types aneurysms
Explore the risk factors associated with aneurysms
Outline which modalities are to diagnose an aneurysm
Explain the different types of surgical intervention used to treat aneurysms

3. Definition of an Aneurysm
A localized dilation of an artery that most commonly involves the aorta, especially its abdominal portion.1

4. Two Classifications of Aneurysms
True aneurysm
An aneurysm that forms with at least one vessel layer still intact.2
False aneurysm
Also known as a pseudoaneurysm, is not aneurysm but a disruption of all arterial wall layers with bleeding that is contained by surrounding anatomic structures.2

5. Two Classifications of Aneurysms
Types of True Aneurysms
False Aneurysm
1. Fusiform
Affects entire circumference of the vessel
Most commonly found in the abdominal region
2. Saccular
Affects only one side of the vessel
3. Dissecting
Inner layers of the vessel tear allowing blood to escape
Most commonly found in the thoracic region
Pseudoaneurysm
Similar in appearance to a dissecting aneurysm
All layers of vessel are affected
Usually caused by a hematoma after trauma to the vessel

6. Classifications of Aneurysms3

7. Definition of a Abdominal Aortic Aneurysm (AAA)
AAA is an aneurysm located in the descending aorta typically below the renal arteries and above the bifurcation into the common iliac arteries.
About 75% of all aneurysms are found in the abdominal aorta. 2
Of the 75% of aneurysms found in the abdomen, about 80% occur below the renal arteries and above the bifurcation into the iliac arteries.4

8. Who's at Risk? Controllable Risk Factors Uncontrollable Risk Factors
Tobacco use is considered the most significant risk factor.
Other risk factors include hypertension, high cholesterol, and excessive weight or obesity.
Being male and older in age are the two most significant uncontrollable risk factors.
Other risk factors include family history of aneurysms and race. Being White or Native American puts you at greater risk when compared African America, Hispanic, or Asian American.

9. Importance of Early Detection
The mortality rate of an emergency AAA procedure is about 40%. Mortality rates for scheduled and pre-monitored AAA procedures drops significantly lower, ranging from 0.6% to 5.3%.4
The biggest problem with early detection of a AAA is that they are often asymptomatic. Due to being asymptomatic, a AAA is often an incidental finding.
If one is experiencing symptoms of a AAA, it may present itself as back pain, epigastric discomfort, irregular bowel movements, or loss of pulse to the lower extremities.

10. Detection of Abdominal Aortic Aneurysm
There are many modalities that can detect a AAA, however, some provide more information about the aneurysm then others.
Plain film radiography
Sonography
Magnetic resonance imaging
Computed tomography

11. Plain Film X-Ray Least common modality used to diagnose AAAs.
Poor soft tissue differentiation makes it difficult to diagnose a AAA on x-ray.
It is possible to make a diagnosis if there is increased calcification on the descending aorta.

12. Sonography Ability to obtain accurate measurements from the images
Pros:
Cons:
Ability to obtain accurate measurements from the images
Quick exam
Doesn’t ionizing radiation
Relatively cost effective
Being overweight can prevent the sonographer from achieving quality images

13. Magnetic Resonance Imaging (MRI)
Pros:
Cons:
Very detailed images of soft tissue structures
Uses no ionizing radiation
Doesn’t require contrast media
High resolution image allows for accurate measurements of the AAA
Ability to reconstruct in 3D
Exams are often timely
Typically higher cost when compared to other modalities
Most insurance companies will cover a CT vs an MRI do to the cost differential

14. Computed Tomography (CT) “The Gold Standard”
Pros:
Cons:
Detailed images of soft tissue structures
Quick scan time
Typically lower cost compared to MRI
Very accurate measurements
Ability for 3D reconstruction
Use of contrast media
Uses ionizing radiation

15. Screening for an Aneurysm
Early detection is an important step to surviving a Abdominal Aortic Aneurysm.
Screening is recommended for males over the age of 65 with a history of smoking or family history of aneurysms. These factors nearly doubles the risk of developing a AAA.5
Sonography is the gold standard for AAA screenings due to its lower cost and lack of ionizing radiation.
If a AAA is suspected, a follow up CT is used to gain crucial information about the aneurysm.

16. When is intervention needed
Vessel dilation refers to 0cm and 3cm growth of the vessel.
An aneurysm defined as dilation larger then 3cm.
It is widely accepted that if an aneurysm exceeds 5.5cm of dilation, surgical intervention is needed.
If the aneurysm is greater than 5.5cm the risk of rupturing far exceeds the risks involved with surgery.

17. Endovascular Aneurysm Repair (EVAR)
Benefits of EVAR
Possible complications
Performed in Interventional Radiography
A stent is placed via the femoral artery to prevent blood flow from weakening the vessel walls further
Minimally invasive procedure
Correct placement of the stent can be difficult
Higher possibility of the stent kinking
Endoleakage of blood around the stent
A new aneurism can grow above or below the new stent

18. Open Surgical Repair “The Gold Standard”
Benefits of Open Surgical Repair
Possible Complications
Performed in Surgery
A graft is accurately secured in place above and below the aneurysm
This accurate placement decreases the potential for post procedural complications
Increased risk of infection due to the invasive nature of open surgery
A new aneurysm can grow above or below the graft

19. Post Surgical Follow Up
For patients who underwent open surgical repair, a follow up CT scan is recommended within 5 years of the surgery.4
For patients who underwent an EVAR, due to the increased possibility of complications, follow up CT scans are recommended at the 1, 3, and 6 month marks as well as yearly follow up scans.4
It is important to note that overtime patients that underwent an EVAR will be exposed to significantly higher amounts of ionizing radiation when compared to patients that underwent open surgical repair.

20. In Conclusion
Knowing the risk factors associated with AAAs is an important step for early detection.
If you may be at risk, screening can detect a dilation before it turns into an aneurysm.
Monitoring the growth of the aneurysm though different modalities insures you have accurate information if intervention is needed.
Choose the best surgical intervention for you based of possible complications and post surgical procedures.

21. References
R. Eisenburg, N. Johnson. Comprehensive Radiographic Pathology. 6th ed. St. Louis, MO: Elsevier; 2016.
S. Lewis, S. Dirksen, M. McLean, L. Bucher. Medical Surgical Nursing, Assessment and Management of Clinical Problems. 9th ed. St Louis, Missouri: Elsevier Mosby; 2014.
Vascular Pathology. In: Dr. Roy. Study Blue [website] Accessed March 27,
J. Legg, L. Legg. Abdominal Aortic Aneurysms. Radiologic Technology. 2016;88(2):
O. Stackelberg, A. Wolk, K. Eliasson, ed al. Lifestyle and Risk of Screening-Detected Abdominal Aortic Aneurysm in Men. Journal of the American Heart Association ;6(5). Doi: /jaha