NEW YORK (Reuters Health), Jan 7 - Only about half of small abdominal aortic aneurysms (AAA) will increase in size, and those that grow less than 1.5 mm per year are seldom of clinical relevance, new research suggests.
The findings, based on 25 years of aneurysm surveillance in the UK, indicate that at baseline, small AAA display a unimodal distribution in size. However, after a few years of follow-up, the distribution becomes bimodal.
The results suggest that half of small AAA remain "quiescent with little growth," while the others continue to expand, senior author Dr. H. Hafez, from Western Sussex Hospital NHS Trust, Chichester and colleagues note in the British Journal of Surgery for January.
In the Chichester AAA screening program, data from 1,649 subjects with an AAA were collected prospectively from 1984 to 2007. In the 1,231 participants who had more than one ultrasound study and surveillance of more than three months, the median AAA diameter at baseline was 35 mm and the median growth over 3.2 years of follow-up was 9 mm.
Aneurysms ruptured in 88 patients and were electively repaired in 335, the report indicates. The median growth rates in patients who had rupture or surgery were 2.85 and 2.99 mm/year, respectively. By contrast, in subjects who were followed uneventfully, the aneurysms grew at a median rate of just 1.08 mm/year (p < 0.001).
Current smoking was associated with an increased AAA growth rate, whereas female gender and diabetes were linked to decreased growth rates. Age, mean arterial pressure, hypertension, ischemic heart disease, and use of ACE inhibitors or statins did not affect the growth rate.
"This study suggests that it may be possible to predict the likelihood of future clinical events based on the pattern of AAA growth," Dr. A. Nasim, from Leicester Royal Infirmary, UK, writes in an accompanying editorial. "This, combined with the fact that only 27.2% of the cohort ended up requiring AAA repair during follow-up, offers significant potential, as the authors suggest, for improving the cost-effectiveness of AAA screening and surveillance."
Br J Surg 2010;97:37-44.
Last Updated: 2010-01-06 12:44:57 -0400 (Reuters Health)
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