Screening for Abdominal Aortic Aneurysm

Abdominal Aortic Aneurysm (AAA) is a common disease with a prevalence of 1.5-2.0%
in 65-year old men in Sweden. The risk of having AAA is increased with smoking, high
age, family history of AAA and cardiovascular disease. Women have a lower prevalence 
(0.5%) and develop AAA later in life. An AAA seldom gives any symptom prior to rupture. 
Untreated rupture is associated with 100% mortality, while surgically treated rupture is 
associated with 25-70% mortality. Prophylactic surgery is associated with a relatively low 
risk (30-day mortality of 1-3%). Commonly, prophylactic surgery is offered at size 5.5 cm 
in men and 5.0 cm in women. As a result of randomized trials showing a benefit in terms 
of AAA-related mortality and all cause mortality, screening of 65-year old men have been 
implemented in Sweden. If a high proportion of invited persons chose not to participate 
in as creening programs, this will affect the positive effects of a screening program. Efforts 
to better understand and thereby to improve the participation rate should be made. This 
thesis is focused on different aspects of screening for AAA.



In the  first  and  second  studies  we  investigated  siblings  to  AAA-patients  in  two 
different  regions  in  Sweden.  We  examined  150  siblings  in  mid-Sweden  (Stockholm) 
and 379 siblings in north Sweden (Norrbotten). In both regions a prevalence of 17% in 
brothers and 6% in sisters was found, strikingly high numbers as compared to the general 
population. We did not detect regional differences in prevalence. Further analysis of the 
53 siblings found with AAA revealed that 32% had a large AAA and 16% had a large AAA 
before the age 65. Organized screening of both male and female siblings is motivated since 
the population-based screening is not sufficient for all of them. 



The third  study  investigated  reasons  for  non-participation  in  the  population 
based AAA-screening program in Stockholm County. The individual socioeconomic- and 
health-status of 24319 men invited to screening was investigated and compared between 
participants and non-participants in screening. The risk of non-participation is increased 
with low income, low education, marital status single, immigrants and persons with long 
travel distance to examination-centre. The non-participants had a higher proportion of 
co-existing diseases. We concluded that immigrants and people with long travel-distance 
should be targeted in further attempts to improve screening-participation. 



The fourth study concerns men with screening-detected AAA and their outcome 
when  treated  with  prophylactic  surgery.  We  compared  all  available  treated  screeningdetected men in Sweden (n=350) to age matched, non screening-detected controls. There 
was  no  differences  in  comorbid  conditions  between  the  groups  but  open  repair  was 
used more frequently than EVAR in patients with screening-detected AAA´s than in nonscreening-detected controls (56% vs 45%).



In terms of outcome, a lower 90-day mortality in screening-detected men was found, but 
no difference in 30-day or 1-year mortality. The overall 30-day mortality in all 700 men 
was very low at 1%. This gives further support to national screening programs for the 
detection of AAA´s in men.



Efforts should be made to find AAA’s with improved screening of siblings and groups with 
low participation-rates in the screening programs