Aortic Aneurysms

Mark A. Farber, MD

Aortic AneurysmsIncidence

• 30-60/1000

• Increasing incidence over past 3 decades

Incidence of AAAAutopsy 1.5-3.0%

U/S Screening 3.2%

Pts with CAD 5.0%

Pts with PVD 10.0%

Pts with femoral and pop.aneurysms 50.0%

Aortic AneurysmsDefinition

• 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 AneurysmsAssociated Aneurysms

• Iliac - 41%

• Femoro-popliteal - 15%

• Pts with unilateral popliteal aneurysms-->8% AAA

• Pts with bilateral popliteal aneurysms--> 30%-50% AAA

Aortic AneurysmsAssociated Medical Conditions

• Carotid Artery Stenosis - 10% have AAA

• Smoker:Nonsmoker - 8:1

• Male:Female - 4:1

• HTN - 40% of pts with AAA have HTN

Aortic AneurysmsEtiology

• Atherosclerosis

• Cystic Medial Necrosis

• Dissection

• Ehlers-Danlos Syndrome

• Syphilis

• Familial Associated– Lysyl Oxidase deficiency

Aortic AneurysmsEtiology

• Decrease in elastin and collagen in arterial wall

• Elastin becomes fragmented-->arterial elongation and dilatation

• Increase in the collagenase and elastase activity

Aortic AneurysmsEtiology

Multifactorial

Aortic AneurysmsPhysics

• Laplace’s Law

T = P x R

T - Tension

P - Pressure

R - Radius

Aortic AneurysmsClinical 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 AneurysmsRuptured Aneurysms

• Small tear-> pain, followed by frank rupture

• Usually occurs postero-laterally

• Can rupture in Vena Cava creating Aorto-Caval Fistula

• Occasionally can rupture anterior - usually fatal

Ruptured AneurysmThumbnail Sketch

• 60-70 y/o who presents with c/o abd pain, hypotension and a pulsatile abdominal mass

Aortic AneurysmsDiagnosis

• 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 AneurysmsDiagnosis

• Arteriography:– Cannot determine aneurysm size because of mural

thrombus– Indications for obtaining arteriography

• 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 AneurysmsDiagnosis

• 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 AneurysmsCT Scan

• 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 AneurysmsMRA

• Now widely available

• More expensive than CT

• No contrast agent required

• Spacial resolution less than CT

Aortic AneurysmsRisks

• Complications of AAA– Thrombosis– Distal embolization– Rupture Size Yearly

Rupture Rate5 YearRisk

5-6 cm 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 AneurysmsRupture 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 AneurysmsTreatment 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 AneurysmsIndications 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 AneurysmsTreatment-Surgical

• Standard Surgical Repair– Replace diseased aorta with artificial artery– Requires 7 day hospital stay– Recovery time 3-6 months– Proven method with good long term results

Aortic AneurysmsTreatment - 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