Screening Guidelines and Treatment Options for Abdominal

Aortic Aneurysms

                                                                               

Allen Jeremias, MDDivision of Cardiology

Beth Israel DeaconessMedical Center

Harvard Medical School

AAA

• Normal size: 2 cm

• AAA: 3 cm

• Prevalence: 1.3% in men aged 45-54 BUT 12.5% in age 75-84

• Risk factors: Same as CAD but mainly hereditary and tobacco

• Natural history: Gradual expansion; mural thrombus

• Complications: Rupture; thromboembolism; compression or erosion of adjacent structures

AAA

AAA-related Mortality

• 13th leading cause of death in US

• Documented 15K but likely up to 30k deaths per year

• Mean F/U of 8 years

Natural History

• Yearly Growth Rates:0.19 cm for AAA 2.8 to 3.9 cm 0.27 cm for AAA 4.0 to 4.5 cm0.35 cm for AAA 4.6 to 8.5 cm

• Rupture Rate at 5 years:AAA >6 cm – 43% vs. 20% for smaller AAA

• Estimated Risk of Rupture:0 in AAA less than 4.0 cm0.5 to 5% for AAA 4.0 to 4.9 cm 3 to 15% for AAA 5.0 to 5.9 cm 10 to 20% for AAA 6.0 to 6.9 cm20 to 40% for AAA 7.0 to 7.9 cm30 to 50% for AAA 8.0 cm

Clinical Presentation

• Most AAA quiescent until rupture

• Rarely Abd. pain or back pain

• New pain and tenderness indicate recent expansion

• Thromboembolism to lower extremities

• Ruptured AAA: Triad of Abd. or back pain, hypotension, and pulsatile Abd. mass

Physical Examination

• 30% of asymptomatic AAA discovered during routine PE

• Pulsatile large Abd. mass

• Sensitivity of PR 22-96%

Screening – Benefit?

• In men age 50+ 49% decrease in AAA rupture in 5 years

• In men age 50+ 64% decrease in AAA rupture in 9 years

Wilminek et al. JVS 2003

Screening – Benefit?

• Population based study of 67,800 men aged 65-74 with random allocation to Abd. US

• Yearly US for AAA> 3 cm and surgery for AAA> 5.5cm or 1 cm progression within 1 year

• 4-year aneurysm-related mortality in control group: 0.33% vs. 0.19% (RR reduction 42%)

• Total of 47 fewer deaths in screening group

MASS: BMJ 2002

Screening – Cost

• Additional cost in screening group: $3.5 million

• Incremental cost-effectiveness ratio: $45,000 per life-year gained

• 10-year estimate: $12,500 per life-year gained

• Recommendation: Screening for ‘high-risk’ groups

MASS: BMJ 2002

Screening Guidelines

Class I

• Men age 60+ with FHx of AAA PE and US

Class IIa

• Men age 65 – 75 with h/o tobacco PE and USx1

BUT: No screening for non-smokers and women! ACC/AHA Guidelines for PVD; JACC 2006

Imaging - US

• Optimal for screening – cheap, easy and no radiation exposure

• Sensitivity almost 100%

• No visualization of iliac arteries

• Dependence on sonographer

• 2-3% of patients cannot be imaged

Imaging – CT/MRI

• Better definition of AAA shape

• Better image suprarenal AAA

• Detection of other Abd. pathology

• Other vascular structures visible (renal, iliac arteries)

Follow-up Surveillance

Aortic diameter <3 cm — no further testing

Aneurysm 3 to 4 cm — annual ultrasound Aneurysm 4 to 4.5 cm — ultrasound every

six months Aneurysm >4.5 cm — referral to a

vascular specialist

Society for Vascular Surgery

Follow-up Surveillance

• AAA <4.0 cm annual US

• AAA 4.0 – 5.4 cm bi-annual US

• Consider intervention when AAA >5.5 cm or >0.5 cm expansion within 6 months

• Also, intervention with Abd./back pain or tenderness and embolism

ACC/AHA Guidelines for PVD; JACC 2006

Observational Management

Class I

• Peri-operative BB therapy for Pt. with CAD

Class IIb

• BB therapy to reduce rate of AAA expansion

ACC/AHA Guidelines for PVD; JACC 2006

Intermediate Size AAA (4-5.5 cm)

UK Small Aneurysm trial

• Randomized 1090 Pt. to surgery vs. US surveillance every 6 months

• Operative mortality 5.4%

• Mean F/U of 8 years Lancet 1998

Intermediate Size AAA (4-5.5 cm)

US ADAM Study

• Randomized 1136 Pt. to surgery vs. US surveillance every 6 months

• Operative mortality 2.7%

• Mean F/U of 5 yearsLederle et al., NEJM 2002

Therapy

Surgery

• Peri-operative mortality 2.7-5.6%

• 40-70% mortality for ruptured AAA surgery

• Significant morbidity (5-12 weeks before returning to normal life style)

Therapy

EVAR

• Peri-operative mortality 1.0-2.4%

• May have lower mortality for ruptured AAA surgery

• Recovery within 1-3 days

Surgery vs. EVAR

Therapy - EVAR

Therapy - EVAR

Surgery vs. EVAR

Dream Trial

• Randomized 351 Pt. to surgery vs. EVAR

• Peri-operative survival advantage with EVAR lost beyond 1 year

Blankensteijn et al., NEJM 2005