By Martin Björck
We know from the randomised controlled trials from the UK, Denmark and West Australia that screening elderly men for abdominal aortic aneurysm with ultrasound saves lives and is cost-effective. According to the latest results from the British MASS trial, screening decreases all-cause mortality by 3% (95% confidence intervals, 1–5%) in the overall screened population—an extraordinary result. These results are the rationale behind the establishment of national screening programmes for 65-year-old men in England and Sweden, and the US Medicare and the Society for Vascular Surgery recommendation of aneurysm screening of men and smoking women. Other countries such as Denmark, The Netherlands and Germany have decided, or are considering starting, aneurysm screening programmes. In Sweden the abdominal aortic aneurysm screening programme began in Uppsala in 2006, and reached national coverage by 2015. Sweden has a population of 9.9 million inhabitants.
Although the overall results of aneurysm screening are persuasive, there are details that still need to be defined. One such detail is whether only the aorta should be examined, or whether the common iliac arteries should also be examined. Most screening programmes are very strict in only examining the aorta, which is what the person invited to screening has consented to. Avoiding examination of the entire abdomen, looking for tumours, etc, is self-evident. We do know, however, that abdominal aortic aneurysm is a disease that often affects also the common iliac, and sometimes the internal iliac arteries and that some patients present with rupture of those iliac arteries.
Since the start of aneurysm screening in Uppsala in 2006 we have routinely examined the common iliac arteries in all subjects who have an aortic diameter ≥25mm. This routine was also used in our neighbouring county of Gävleborg. In total, 35,582 65-year-old men were invited, and 26,334 participated (86%). We used this material to study this controversial issue, Achilleas Karkamanis, vascular surgeon and PhD student in Uppsala, responsible for the investigation.
Among those examined 3% had a diameter ≥25mm, and of those, 79% were examined and had a reliable common iliac artery. A common iliac artery aneurysm was defined as a diameter ≥18mm, and 26% of those examined had an iliac artery aneurysm. As expected, those with abdominal aortic aneurysm (≥30mm) had a higher proportion of common iliac artery aneurysms (30%), compared with those with a common iliac artery diameter of 25–29mm (22%). Among 19 large iliac aneurysms, (≥30mm) requiring surgery, 17 had an abdominal aortic aneurysm. However, the largest common iliac aneurysm—with a diameter of 60mm—was found in a man with an aortic diameter of only 25mm (Figure 1).
In conclusion, most common iliac artery aneurysms would have been identified anyway, since most patients with large common iliac artery aneurysms also have abdominal aortic aneurysms. It does not add much work, however, to also investigate the common iliac artery in patients with abdominal aortic aneurysm or sub-aneurysmal aortas, since they are only 3% of those examined. The benefit of adding this routine is increasing patient safety.
For every man who is invited to and accepts abdominal aortic aneurysm screening and later dies from a ruptured aortic or iliac aneurysm, there is a great loss of confidence in the screening programme. From the perspective of mourning relatives, there is no difference as to whether the aneurysm was in the aorta or in the common iliac artery. As a result, we have decided to continue with this routine, and to continue to gather data in order to evaluate the long-term result of including measurements of the common iliac artery in subjects with an aortic diameter ≥25mm.
Martin Björck, University of Uppsala, Uppsala, Sweden