Abdominal Aortic Aneurysms

Diagnosis and treatment

AAA defintion

Normal aorta Aorta with an abdominal aneurysm

Varies by age, gender, body surface area

Typically diagnosed if aortic diameter is ≥ 3.0 cm*

*ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Prevalence of AAA

In the US, AAA causes almost 14 000 deaths each year and accounts for 63 000 hospital discharges

Age (years) Men Women

2.9 - 4.9 cm45-54 1.3% 0%

75-84 12.5% 5.2%

ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Risk factors associated with AAA

Older age

Male sex

Family hx

Smoking

Hypertension

Dyslipidemia

Atherosclerotic disease

COPD

ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Types of AAA

Morphological classification

• fusiform aneurysms

• saccular aneurysms

• dissecting aneurysms

• pseudo-aneurysms

Segments involved

• thoracic

• thoraco-abdominal

• abdominal

• main branches of the aorta

• iliac arteries

AAA Sequelae

Natural history• gradual and/or sporadic expansion• accumulation of mural thrombus

Complications• rupture• thromboembolic events• compression of adjacent structures

Progression of a AAA

Pathological changes cause the aorta wall to• become thinner• bulge• tear• rupture

Growth rate of AAA

Initial size (cm)

Mean growth rate (cm/yr) 95% CI

3.0- 3.9 0.39 0.20-0.57

4.0-4.9 0.36 0.21-0.50

5.0-5.9 0.43 0.27-0.60

6.0-6.9 0.64 0.16-1.10

Tan W Abdominal Aortic Aneurysm Rupture www.emedicine.com

Symptoms of AAA rupture

Abdominal/back pain

Pulsatile abdominal mass

Hypotension

Clinical triad occurs in only about one-third of cases.

ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

AAA: risk of rupture

Simplifed estimates based on various studies

Tan W Abdominal Aortic Aneurysm Rupture www.emedicine.com

0

Risk of rupture for untreated aneurysm within 5 years (%)

10

7060

4050

3020

80

25%35%

75%

Aneurysm size5-5.9cm 6-6.9cm ≥7cm

Rupture outcomes

Mortality rate can be as high as 80%[1]

More than one third of rupture cases die outside the hospital[2]

Ruptured AAA

1. Adam. J Vasc Surg 1999;30:922-8.

2. Thomas. Br J Surg Aug 1988

Operative mortality

35-70% for ruptured aneurysm

Pae. J Am Surg 2007; Qureshi. Ann Vasc Surg 2007; Greco. J Vasc Surg 2006; Pepplenbosch. J Vasc Surg 2006; Visser. Eur J Vasc Endovasc Surg 2005; Brown. Br J Surg 2002; Heller. J Vasc Surg 2000; Adam. J Vasc Surg 1999; Johansen. J Vasc Surg 1991; Ouriel. J Vasc Surg 1990.

1.0-8.0% for elective AAA casesQureshi. Ann Vasc Surg 2007; Cowan. Ann NY Acad Sci 2006; Heller. J Vasc Surg 2000; Bradbury. Br J Surg 1998; Blankensteijn. Br J Surg 1998.

ACC/AHA screening high-risk

Men ≥ 60 yrs who are siblings or offspring of AAA patients

Men 65-75 yrs who have ever smoked

Physical exam and ultrasound

ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Class IClass IIa

Class IIbClass III

Diagnosis: physical exam

In one study (N=198)• 48% of AAA cases were diagnosed clinically• physical exam missed 38% of cases detected

radiologically

Karkos CD. Eur J Vasc Endovasc Surg 2000;19:299-303.

Sensitivity of physical exam

Lederle. JAMA 1999;281:77-82.

Aneurysm diameter

Sensitivity

3.0-3.9 cm 29%

4.0-4.9 cm 50%

≥ 5.0 cm 76%

Pooled analysis of 15 studies

Sensitivity of ultrasound

Ranges from 82% to 99%

Approx 100% in cases with a pulsatile mass

In a small proportion of patients, visualization of the aorta inadequate due to obesity, bowel gas, or periaortic disease

Quill. Surg Clin North Am 1989;69:713-20.

Ultrasound screening

5

20

8

29

9

27

0

5

10

15

20

25

30

Number

Emergency Ops Rupturedaneurysms

AAA deaths

Screened Control

Lindholdt. BMJ 2005;330:750.

Controlled screening trial of men age 65 to 73 ITT analysis n=6333 screened, n=6306 control

P=0.002P=0.001 P=0.003

ACC/AHA Guidelines AAA repairInfrarenal/juxtarenal AAA ≥5.5 cm should undergo repair; 4.0-5.4 cm, ultrasound/CT scans every 6-12 mo

Repair can be beneficial for infrarenal/juxtarenal AAAs 5.0-6.0

cm

Repair probably indicated for suprarenal/type IV thoracoabdominal AA >5.5-6.0cm

AAA <4.0cm, ultrasound every 2-3 years is reasonable

Intervention not recommended asymptomatic infrarenal/ juxtarenal AAAs <5.0 cm (men) or <4.5 cm (women)

ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Class IClass IIa

Class IIbClass III

Treatment options

Endovascular stent graftingOpen surgery

Open repair: advantages

Established procedure more than 40 years of clinical experience

Excludes aneurysm and prevents sac growth

Proven, long-term results

Open surgical repair (OSR): drawbacks

Significant incision in the abdomen

30–90 minute cross-clamp

Up to 4-hour procedure

1–2 days intensive care7–14 days hospitalization4–6 weeks recovery time

Contraindications to OSR

High anesthesia risk

Severely obese

Significant cardiac co-morbidities

Previous abdominal surgery/hostile abdomen

Difficult recovery for patient:

• risks functional impairment [1]

• risk of erectile dysfunction [2]

1. Williamson. J Vasc Surg 2001;33:913-920.

2. Lee. Ann Vasc Surg 2000;14:13-19.

Early OSR vs watchful waiting

Endpoint Relative risk 95% CI

All cause mortality 1.01 0.77-1.32

Aneurysm-related mortality 0.78 0.56-1.10

Combined ADAM and UKSAT trials of early/immediate OSR vs surveillance/delayed OSR for AAA < 5.5 cm

N = 2226

Lederle. Ann Intern Med 2007;146:735-741.

Endovascular aneurysm repair (EVAR)

Benefits• minimally invasive• reduced risk of

perioperative death• faster recovery

Preoperative angiogram Postoperative angiogram

®

AAA repair with stent graft

EVAR

Drawbacks

Complications and re-interventions• intrasac endoleaks• stent graft migration• modular dislocation

Morphology suitable for endovascular repair

• adequate vascular access

• appropriate aortic neck length and angulation

Endovascular stent grafting

EVAR vs OSR 30-day outcomes

Trial Endpoint EVAR OPEN P

EVAR [1]

N=1082 ≥ 5.5 cm

Mortality 1.7 % 4.7 % 0.009

Secondary interventions

9.8 % 5.8 % 0.02

DREAM [2] N=345

≥ 5.0 cm

Mortality 1.2 % 4.6 % 0.1

Mortality & severe complications

4.7 % 9.8 % 0.1

1. Lancet 2004;364:843-8.

2. N Engl J Med 2004;351:1607-1618.

EVAR vs OSR 2-year outcomesDREAM

Endpoint EVAR OPEN P

Survival 89.7% 89.6% 0.86

Survival free of moderate-severe complications

65.6% 65.9% 0.88

Aneurysm-related death 2.1% 5.7% 0.05

N Engl J Med 2005;352:2398-405.

DREAM: sexual dysfunction*

Both EVAR and open repair have a negative impact on sexual function in the early postoperative period.

After EVAR, recovery to preoperative levels is faster than after open repair.

At 3 months, sexual dysfunction levels are similar in both groups.

*Measured 5 aspects (interest, pleasure, engagement, orgasm, erection)

N=153

Prinssen. J EndovascTher 2004;11:613-620.

Erectile dysfunction

Erectile function worsened after open repair (p=0.002)

Orgasmic function deteriorated after open repair (p=0.001)

Endovascular repair was not accompanied by decreased erectile or orgasmic function (p=0.057 and p=0.068, respectively)

Impairment not associated with age, diabetes, or number of patent hypogastric arteries after repair

Significant association between impaired erectile function and open aneurysm repair (p=0.036)

N=90

Xenos. Ann Vasc Surg 2003;17:530-538.

Agency for Healthcare Research & Quality review of EVAR vs open surgical repair

Lower perioperative morbidity and mortality

Persistent reduction in AAA-defined mortality to 4 years

No improvement in long-term overall survival or health status

For AAA ≥ 5.5 cm

AHRQ Publication No. 06-E017 August 2006

Medicare cohort 4 yr outcomes

Endpoint* EVAR OPEN P

Periop mortality 1.2 % 4.8 % <0.001

AAA rupture 1.8 % 0.5 % <0.001

AAA reintervention 9.0% 1.7% <0.001

Laparotomy-related

Reintervention 4.1% 9.7% <0.001

Hospitalization 8.1% 14.2% <0.001

Schmermerhorn N Engl J Med 2008;358:464-474.

* All 4 yr except perioperative mortality N=22 830 matched patients

Ongoing studies EVAR vs OSR

France• Anévrisme de l’aorte abdominale: chirurgie

versus endoprothèse (ACE)ClinicalTrials.gov identifier: NCT00224718

US• Open versus endovascular repair (OVER) trial

for AAA • ClinicalTrials.gov identifier: NCT00094575