Aortic Aneurysms
Mark A. Farber, MD
Aortic Aneurysms
Incidence
• 30-60/1000
• Increasing incidence over past 3 decades
Incidence of AAA
Autopsy
U/S Screening
Pts with CAD
Pts with PVD
Pts with femoral and pop.aneurysms
1.5-3.0%
3.2%
5.0%
10.0%
50.0%
Aortic Aneurysms
Definition
• Pseudoaneurysm
• True Aneurysm
Definitions
• Aneurysm - Increase in diameter of 50%
(1.5x) its normal diameter – Focal region
• Ectasia - Diffuse dilatation of an artery with
increase in diameter >50%
• Arteriomegaly - Diffuse enlargement of an
artery, but not lg. Enough to meet criteria
for an aneurysm
Aortic Aneurysms
Associated Aneurysms
• Iliac - 41%
• Femoro-popliteal - 15%
• Pts with unilateral popliteal aneurysms->8% AAA
• Pts with bilateral popliteal aneurysms-->
30%-50% AAA
Aortic Aneurysms
Associated Medical Conditions
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Carotid Artery Stenosis - 10% have AAA
Smoker:Nonsmoker - 8:1
Male:Female - 4:1
HTN - 40% of pts with AAA have HTN
Aortic Aneurysms
Etiology
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Atherosclerosis
Cystic Medial Necrosis
Dissection
Ehlers-Danlos Syndrome
Syphilis
Familial Associated
– Lysyl Oxidase deficiency
Aortic Aneurysms
Etiology
• Decrease in elastin and collagen in arterial
wall
• Elastin becomes fragmented-->arterial
elongation and dilatation
• Increase in the collagenase and elastase
activity
Aortic Aneurysms
Etiology
Multifactorial
Aortic Aneurysms
Physics
• Laplace’s Law
T=PxR
T - Tension
P - Pressure
R - Radius
Aortic Aneurysms
Clinical Presentation
• Asymptomatic - 70-75%
• Symptoms:
– Early satiety, N,V
– Abd., Flank, or Back pain
– 1/3 of pts experience abd. And flank pain
• Abrupt onset of pain -->Rupture or
expansion of aneurysm
Aortic Aneurysms
Ruptured Aneurysms
• Small tear-> pain, followed by frank rupture
• Usually occurs postero-laterally
• Can rupture in Vena Cava creating AortoCaval Fistula
• Occasionally can rupture anterior - usually
fatal
Ruptured Aneurysm
Thumbnail Sketch
• 60-70 y/o who presents with c/o abd pain,
hypotension and a pulsatile abdominal mass
Aortic Aneurysms
Diagnosis
• Physical Exam:
– If <5cm in diameter, then cannot be detected by
routine physical exam
• Radiographs:
– Calcified wall. Can determine size in 2/3
– Cannot rule out and AAA
Aortic Aneurysms
Diagnosis
• Arteriography:
– Cannot determine aneurysm size because of
mural thrombus
– Indications for obtaining arteriography
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Suspicion of visceral ischemia
Occlusive disease of iliac and femoral arteries
Severe HTN, or impair renal function
? Horseshoe Kidney
Suprarenal of TAAA component
Femoro-Popliteal Aneurysms
Aortic Aneurysms
Diagnosis
• Ultrasound
– Establishes diagnosis easily
– Accurately measures infrarenal diameter
– Difficult to visualize thoracic or suprarenal
aneurysms
– Difficult to establish relationship to renal arteries
– Technician dependent
– Widely available, quick, no risk, cheap
Aortic Aneurysms
CT Scan
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Very reliable and reproducible
Can image entire aorta
Can visualize relation ship to visceral vessels
Longer to obtain and is more costly than U/S
Most useful
Requires contrast agent - renal toxicity
Aortic Aneurysms
MRA
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Now widely available
More expensive than CT
No contrast agent required
Spacial resolution less than CT
Aortic Aneurysms
Risks
• Complications of AAA
– Thrombosis
– Distal embolization
– Rupture
Size
5-6 cm
Yearly
5 Year
Rupture Rate
Risk
5-10%
25-50%
6-7 cm
7-15%%
30-75%
>7 cm
20-30%
>90%
23.4% of aneurysms 4-5 cm will rupture
Aortic Aneurysms
Rupture Risks
• Patients with COPD and HTN have
increased risk of rupture
• Rate of enlargement:
– 0.5 cm/ year
• Survival
– 50% die prior to reaching hospital, and an
additional 24% prior to repair.
Aortic Aneurysms
Treatment Risks
• Mortality
– 0.9 - 5% with current surgical techniques
• Morbidity
– 5-10% usually associated with cardiac events
• Endovascular Techniques are significantly
reducing morbidity and mortality associated
with repair
Aortic Aneurysms
Indications for Treatment
• Presence of an infrarenal aneurysm > 5cm without
associated co-morbid medical conditions
• Repair smaller aneurysms if rate of enlargement is
greater than expected
• Repair all symptomatic aneurysms
• If co-morbid conditions exist wait until risk of repair
and rupture are equal (approx. 6 cm)
Aortic Aneurysms
Treatment-Surgical
• Standard Surgical Repair
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Replace diseased aorta with artificial artery
Requires 7 day hospital stay
Recovery time 3-6 months
Proven method with good long term results
Aortic Aneurysms
Treatment - Endovascular
• Repair through an incision in the groin with
expandable prosthesis under fluoroscopic
guidance
• Requires both surgical and radiological
assistance
• Significantly reduced m+m
• Long tern result unknown
• Hospital stay 2 days, Recovery time 1-2 weeks