1-Abdominal Aortic Aneurysm Flashcards
what is the abdominal aortic aneurysm (AAA)?
A focal dilatation of the abdominal aorta to more than 1.5 times its normal diameter. Most commonly infrarenal. Frequently asymptomatic and detected incidentally.
what is the definition of AAA?
Abdominal Aortic Aneurysm is a dilation of the abdominal aorta (> 3cm) formed by widening of the lumen secondary to weakness of the aortic wall, that may extend proximally or distally along the artery
what is the epidemiology of AAA?
- -Peak incidence: 60–70 years (rare in patients < 50 years)
- -Sex: ♂ > ♀: ∼ 2:1
- -More common in white populations
AAA is more common in females. True/False
False
–Sex: ♂ > ♀: ∼ 2:1
AAA is commonly combined with other aneurysms. True False
True
25% of patients with AAA have coexisting femoral or popliteal aneurysms
what are the risk factors of AAA?
- -Advanced age
- -Smoking (most important risk factor)
- -Atherosclerosis
- -Hypercholesterolemia and arterial hypertension
- -Positive family history
- -Trauma
what is the most important risk factor of AAA?
smoking
classify the aneurysm
- True / False
- Anatomical
- Aetiology
–Degenerative
–Inflammatory
–Infective
–Traumatic
–Post dissection
4)Below the renal arteries
Most common location
5)Above the renal arteries
6)anatomical location
- aortoiliac
- suprarenal
- thoracic/TAA
- femoral
AAA most commonly is below or above renal arteries?
below
what is the pathophysiology of AAA?
- -Inflammation and proteolytic degeneration of connective tissue proteins (e.g., collagen and elastin and/or smooth muscle cells) in high-risk patients → loss of structural integrity of the aortic wall → widening of the vessel → mechanical stress (e.g., high blood pressure) acts on weakened wall tissue → dilation and rupture may occur.
- -The aneurysmatic dilatation of the vessel wall may cause disruption of the laminar blood flow and turbulence.
- -Possible formation of thrombi in the aneurysm → peripheral thromboembolism
what is the difference between true and false aneurysm?
1) Involves all three layers of the vessel wall (i.e., tunica intima, tunica media, tunica adventitia).
2) A collection of blood that forms due to a vessel wall defect. Can result in the accumulation of blood between the tunica media and the tunica adventitia or between the blood vessel and surrounding tissue.
AAA is commonly asymptomatic or symptomatic?
Asymptomatic - 75%
- Routine examination
- Ultrasound Sound scanning/Plain
- Film Abdomen for other reason
- Patient notices pulsatile mass
how AAA is usually detected?
on routine examination by USG
what are the complications of AAA?
• Distal Embolisation(blue toe syndrome)
• Leak
(abdominal/back /flank pain)
• Rupture
(hypovolaemic shock, sudden epigastric/back pain)
• Fistulation – “Rare”
(aorto-caval/aorto-enteric)
what are the signs and symptoms of AAA?
- -Aortic aneurysms are mostly asymptomatic or have nonspecific symptoms. Therefore, they are often incidental findings on ultrasound or CT scan. Rupture or dissection of the aneurysm is a life-threatening condition
- -Lower back pain
- -Pulsatile abdominal mass at or above the level of the umbilicus
- -Bruit on auscultation
- -Peripheral thrombosis and distal atheroembolic phenomena (e.g., blue toe syndrome and livedo reticularis)
- -Decreased ankle brachial index
how AAA is assessed?
Clinical Examination
• Inspect for abdominal pulsations at eye level
• Feel for pulsatile/expansile mass in 2 planes
• Listen for bruits
• Examine femoral and popliteal arteries
Assessment: Ultrasound – Diagnose & Size
what technique is used to monitor AAA progression?
USG
An abdominal ultrasound for AAA diagnosis has a sensitivity and specificity of nearly 100%, but may be limited by bowel gas or patient obesity. It also lacks sensitivity for the detection of aneurysmal leaks, branch artery involvement, and suprarenal involvement.
what is the role of CT with contrast in AAA?
determines AAA rupture, suprarenal involvement, and visceral artery involvement.
• Tortuosity
» Involvement of renal arteries
» Evidence of leak
what is the risk of AAA rupture based on size?
- <4—0%
- 4-5–0.5-5%
- 5-6—3-15%
- 6-7—10-20%
- 7-8—20-40%
- > 8—30-50%
what are the indications of AAA surgery?
- Rupture
- Symptomatic - back/flank/abdominal pain, embolisation
- Rapid increase in size >1.0 cm/year
- Asymptomatic ≥ 5.5 cm – exact lower limit controversial
- Aorto-caval/Aorto-enteric fistula
how frequently USG should be done of done based on AAA size?
< 3 cm–No further follow-up
3–4 cm–Ultrasound every year
4–4.5 cm–Ultrasound every 6 months
4.5–5.5 cm–Ultrasound every 3 months
what is the EVAR (endovascular aneurysm repair)?
A minimally invasive technique used to repair aortic aneurysms (e.g., AAA). An expandable stent graft is placed intraluminally under fluoroscopic guidance via the femoral or iliac arteries at the site of the aneurysm, thus excluding the dilated aortic segment from circulation. Known as TEVAR (thoracic EVAR) when performed for a thoracic aortic aneurysm.
which one is preferred EVAR or open surgical repair?
EVARp referred over open surgery; esp. in patients with high operative risk
what is the advantage of EVAR against surgery?
- Suitable for older age groups
- Suitable in significant co-morbid illnesses
- Avoids the major 3 insults of surgery:
1. Laparotomy
2. Aortic Cross-Clamping
3. Ischaemia-Reperfusion
