Aortic Aneurysm Screening Willy Pillay Endovascular Surgeon

Aortic Aneurysm ScreeningWilly Pillay

Endovascular Surgeon

Doncaster Vascular Centre

Background

• AAA in 7.5% of Males > 65yr• 2% of all deaths in males > 65• 6800 AAA-related deaths/yr (Eng&Wales)• 7% risk of family member having AAA• 12% risk if index is female• 3.1% have peripheral aneurysms• 70% of peripheral aneurysms have AAA

Background on AAA

• Treatment when reaches 5.5cm size• Prevent rupture• Elective open surgery mortality – 7.5% in UK (Vascunet Data 2008)– AAA QIP to reduce mortality to 2.5%– 2012: 2.4% (DVC: 3.9%, Now 2.6%)

• Emergency open surgery mortality 40-50%• Elective EVAR mortality 2%• Emergency EVAR mortality ??? (IMPROVE trial)


UK Small Aneurysm Trial

• 1998, Lancet• 1090 patients (age 60 – 76)• Asymptomatic AAA 4.0 – 5.5cm• Early surgery vs. ultrasound surveillance• Surgery if >5.5, increase> 1cm/yr, symptoms• US 6/12 (4.0-4.9), 3/12 (5.0-5.5)• Follow-up 4.6 year (mean)



• Operative mortality was 5.8%• Hazard ratio 0.94 for early surgery (all-cause

mortality)• Mean survival 6.5 and 6.7 years• No increase mortality with delayed surgery• ¾ of surveillance group underwent surgery• ‘early surgery gives no significant survival advantage over

surveillance’ (…delayed surgery)



• 2002, NEJM• Follow-up 8 yrs• 7.2% survival advantage in early surgery• Smoking cessation

Screening• Pro-active: Invite a target population• Opportunistic: e.g. HIV test at Antenatal Clinic• The condition

– An important health problem– Well understood epidemiology, disease progression, Latent period, risk factors– Implemented cost-effective primary prevention strategy

• The Test– Simple, safe, precise, and validated– Repeatable, reliable– Suitable cut-off levels defined and agreed– A further diagnostic test for positive results

• The Treatment– Effective, acceptable and available treatment for early detected disease– Early treatments lead to better outcomes– Clinical management should be optimised

• The Screening Programme– RCT shows that screening reduces mortality & morbidity– Clinically, ethically and socially acceptable to all– Benefit should outweigh physical or psychological harm


MASSMulticentre Aortic Aneurysm Screening Study

• 2002, Lancet• 67800 males (65-74yr)• Invited for US screening or control• 3.0-4.4 annual/ 4.4-5.4 3mthly• Surgery >=5.5, symptoms, increase .1cm/yr• 4.9% incidence AAA (12% >=5.5cm)• Mortality elective 6%, emergency 37%• Follow-up 4.1 yrs (mean)


MASS

• No difference in all-cause mortality (<3% of deaths)

• 42% RRR of mortality due to AAA (hazard ratio 0.58) (0.33 to 0.19)

• NNT = 710 screenings• 41% RRR of rupture of AAA (hazard ratio 0.59)

(0.41to 0.24)• £28 400/ life year gained


MASS

• 2007, Annals Int Med• Follow-up 7 yrs (mean)• £12 000/life year gained• Hazard ratio 0.53

• 2012, BMJ• US<3.0cm rupture risk low• But AAA rupture in those with initial size 2.5-2.9cm

• ?women• ?2nd scan at 75yr if US<3.0cm


Mass (2)

Final follow up of the Multicentre Aneurysm Screening Study (MASS) randomized trial of abdominal ‐aortic aneurysm screening

British Journal of SurgeryVolume 99, Issue 12, pages 1649-1656, 3 OCT 2012 DOI: 10.1002/bjs.8897http://onlinelibrary.wiley.com/doi/10.1002/bjs.8897/full#fig1

http://onlinelibrary.wiley.com/doi/10.1002/bjs.v99.12/issuetoc

http://onlinelibrary.wiley.com/doi/10.1002/bjs.8897/full#fig1

Final follow up of the Multicentre Aneurysm Screening Study (MASS) randomized trial of abdominal ‐aortic aneurysm screening

British Journal of SurgeryVolume 99, Issue 12, pages 1649-1656, 3 OCT 2012 DOI: 10.1002/bjs.8897http://onlinelibrary.wiley.com/doi/10.1002/bjs.8897/full#fig2

http://onlinelibrary.wiley.com/doi/10.1002/bjs.v99.12/issuetoc

http://onlinelibrary.wiley.com/doi/10.1002/bjs.8897/full#fig2

Screening

• Men on 65th birthday• Midline ultrasound AP measurement• >3.0cm Surveillance• >5.5cm Referred for treatment


Workload impact

• Men age 65 = +/- 0.4% of population• Screening men > 65 yr– 4% have slight enlargement– 1% AAA > 4.0– 0.5 % > 5.5cm (i.e. 8 newly detected men with AAA/ 400

000, but screening planned only for men=65!)• Over 20 years (400 000 pop)– Elective ops increase from 61% to 94% of all AAA surgery– Increase 2.1 elective ops/month– Decrease 0.5 emergency ops/month– Increase 1.6 ops/month (after 20 yrs)


A note on screening

• Screening is not fool-proof• Not every detected case will have a successful outcome• Minimum number of false +• Minimum number of false –• Quality assurance (Reproducibility)• Screening = risk reduction NOT diagnosis & cure• Possible harm:

– High M&M of subsequent treatment– Over detection of disease– Psychological effects– Genetic issues


Men > 65Yr

• Self-referral will be incorporated into screening program

• Aorta <3.0cm = 0.54 rupture/ 10 000 person years


Relatives < 65 yr

• Index case– Known AAA– Rupture– Screened case

• Referred to Vascular Surgeon for US/ counselling (outside of screening)


Women

• 1.3% of women vs 7.6% men• Cochrane review AAA screening (2007)– No significant decrease in AAA-related mortality

(OR 2 vs 0.5 for men)– No significant decrease in in rupture (OR 1.5 vs 0.5

for men)– Surgery equally likely if screened or not

• Possibly screen those with family history?

To date

• NHSAAASP: guidance to measure aorta– AP and Longitudinal in Midline– Inner wall to inner wall

• Prevalence in NHSAAASP is 1.5% (2012)– Statins, Smoking

• Elective mortality has decreased to 2.4%

Documents

Aortic Aneurysm Screening Willy Pillay Endovascular Surgeon