Thresholds in women with abdominal aortic aneurysm
Authors: Minna Johansson, Russell P Harris
Journal: The Lancet (2017)

Past studies have found that women have a lower prevalence of abdominal aortic aneurysm,1Svensjö S Björck M Wanhainen A Current prevalence of abdominal aortic aneurysm in 70-year-old women.Br J Surg. 2013; 100: 367-372Crossref PubMed Scopus (89) Google Scholar develop abdominal aortic aneurysm at later ages,2Vänni V Turtiainen J Hakala T et al.Vascular comorbidities and demographics of patients with ruptured abdominal aortic aneurysms.Surgery. 2016; 159: 1191-1198Summary Full Text Full Text PDF PubMed Scopus (15) Google Scholar have higher rates of rupture,3Sweeting MJ Thompson SG Brown LC Powell JT RESCAN collaboratorsMetaanalysis of individual patient data to examine factors affecting growth and rupture of small abdominal aortic aneurysms.Br J Surg. 2012; 99: 655-665Crossref PubMed Scopus (352) Google Scholar and have higher 30-day mortality and more complications from either open abdominal aortic aneurysm repair or endovascular repair (EVAR) than do men.4Grootenboer N van Sambeek MR Arends LR Hendriks JM Hunink MG Bosch JL Systematic review and meta-analysis of sex differences in outcome after intervention for abdominal aortic aneurysm.Br J Surg. 2010; 97: 1169-1179Crossref PubMed Scopus (70) Google Scholar These sex differences have raised questions about thresholds in women: what aortic diameter should be labelled an abdominal aortic aneurysm, and at what diameter should surgical intervention be considered? These were among the questions addressed for men by the UKSAT5Powell JT Brown LC Forbes JF et al.Final 12-year follow-up of surgery versus surveillance in the UK Small Aneurysm Trial.Br J Surg. 2007; 94: 702-708Crossref PubMed Scopus (249) Google Scholar and ADAM6Lederle FA Wilson SE Johnson GR et al.Immediate repair compared with surveillance of small abdominal aortic aneurysms.N Engl J Med. 2002; 346: 1437-1444Crossref PubMed Scopus (982) Google Scholar trials, but these trials included only 198 women in total. In The Lancet, Pinar Ulug and colleagues' systematic reviews with meta-analysis7Ulug P Sweeting MJ von Allmen RS Thompson SG Powell JT on behalf of the SWAN collaboratorsMorphological suitability for endovascular repair, non-intervention rates, and operative mortality in women and men assessed for intact abdominal aortic aneurysm repair: systematic reviews with meta-analysis.Lancet. 2017; (published online April 25)http://dx.doi.org/10.1016/S0140-6736(17)30639-6PubMed Google Scholar adds to our understanding of abdominal aortic aneurysm in women, as they report on sex differences among patients being assessed for intact abdominal aortic aneurysm. They found that a smaller proportion of women than men were eligible for EVAR (34% vs 54%; odds ratio [OR] 0·44, 95% CI 0·32–0·62), a higher proportion of women than men were not offered intervention (34% vs 19%; OR 2·27, 95% CI 1·21–4·23), and 30-day mortality was higher in women than in men for both EVAR (2·3% vs 1·4%; OR 1·67, 95% CI 1·38–2·04) and open repair (5·4% vs 2·8%; OR 1·76, 95% CI 1·35–2·30). Ulug and colleagues highlight the need to design an endograft for women or refer women to centres with endovascular sealing technology or with specialists in open repair. They also point out that women have smaller aortas than men and suggest that “if a smaller threshold for both diagnosis and intervention were introduced, compared with those recommended for men, women might have a better chance of being offered and surviving intervention at a younger age”. As Ulug and colleagues note, the evidence they examined has limitations. Only five studies evaluated morphological eligibility for EVAR and only four single-centre studies addressed non-intervention rates. The results of these studies had considerable heterogeneity, and adjustments for important variables such as age, comorbidity, and smoking history were inconsistent. Although the evidence base is stronger for 30-day mortality after EVAR and open repair—women clearly have higher mortality than men—their review again found important variation in actual rates. Important considerations exist when assessing sex differences in abdominal aortic aneurysm. First, most studies on this topic are from countries where most of the screening for abdominal aortic aneurysm occurs among men rather than women. Generally, screen-detected abdominal aortic aneurysms have a better prognosis than clinically detected abdominal aortic aneurysms, partly because screening results in a higher rate of detection and surgery of abdominal aortic aneurysms that would never have ruptured even without surgery (ie, overdiagnosis and overtreatment).8Johansson M Hansson A Brodersen J Estimating overdiagnosis in screening for abdominal aortic aneurysm: could a change in smoking habits and lowered aortic diameter tip the balance of screening towards harm?.BMJ. 2015; 350: h825Crossref PubMed Scopus (39) Google Scholar Therefore, comparisons of a screened and a non-screened cohort can be misleading. Second, although abdominal aortic aneurysm is less frequent in women, the natural history of abdominal aortic aneurysms that occurs in women might be worse, which does not mean, however, that earlier or more aggressive intervention would reduce mortality. It could, in fact, increase mortality. Third, that women have a higher non-intervention rate than men does not necessarily mean that women have too high a non-intervention rate. Many patients considered unfit for surgery have high competing risks and a short remaining lifespan, with or without surgery.9Scott SW Batchelder AJ Kirkbride D Naylor AR Thompson JP Late survival in nonoperated patients with infrarenal abdominal aortic aneurysm.Eur J Vasc Endovasc Surg. 2016; 52: 444-449Summary Full Text Full Text PDF PubMed Scopus (21) Google Scholar Mortality is not the only measure to consider and future research should include patient-relevant outcomes—eg, unnecessary treatment, physical and cognitive loss after surgery, and ability to return to an independent life after surgery. The suggestion of lowered thresholds for diagnosis and intervention in women is supported by the fact that women in general have smaller aortas than men.10Lo RC Lu B Fokkema MT et al.Relative importance of aneurysm diameter and body size for predicting abdominal aortic aneurysm rupture in men and women.J Vasc Surg. 2014; 59: 1209-1216Summary Full Text Full Text PDF PubMed Scopus (137) Google Scholar However, the higher rate of complications and operative mortality in women instead argues for a higher threshold for elective surgery, since the higher risk of surgery might outweigh any incremental additional benefit from earlier intervention. Aneurysm diameter is a better predictor of rupture in men than in women, where diameter indexed to body size seems superior.11Wanhainen A Björck M Boman K Rutegård J Bergqvist D Influence of diagnostic criteria on the prevalence of abdominal aortic aneurysm.J Vasc Surg. 2001; 34: 229-235Summary Full Text Full Text PDF PubMed Scopus (68) Google Scholar However, a change in the definition of the diagnosis for women might result in increased harm due to overdiagnosis and overtreatment of abdominal aortic aneurysms that would never have caused symptoms. Indeed, studies using alternative definitions (eg, aortic maximum diameter ≥1·5 times normal infrarenal aortic diameter) have shown a prevalence of abdominal aortic aneurysm of up to 10% in women,11Wanhainen A Björck M Boman K Rutegård J Bergqvist D Influence of diagnostic criteria on the prevalence of abdominal aortic aneurysm.J Vasc Surg. 2001; 34: 229-235Summary Full Text Full Text PDF PubMed Scopus (68) Google Scholar which appears to constitute an unacceptably high rate of overdiagnosis considering the relatively low rate of abdominal aortic aneurysm rupture in women. To answer the questions of diagnostic and treatment thresholds in women we need better evidence. We need to know the risk of rupture (not simply progression) and the risk of mortality and treatment complications in untreated versus treated women of different age and comorbidity groups with varying sizes of abdominal aortic aneurysm detected in the same way. In short, we need new randomised trials—this time with only female participants. Additionally, quality-of-life issues are important to explore, preferably with a combination of qualitative and quantitative research approaches, and using disease-specific rather than general questionnaires.12Wiebe S Guyatt G Weaver B Matijevic S Sidwell C Comparative responsiveness of generic and specific quality-of-life instruments.J Clin Epidemiol. 2003; 56: 52-60Summary Full Text Full Text PDF PubMed Scopus (394) Google Scholar It is clear that, with respect to cardiovascular (and other) disease, women and men are different. We cannot simply generalise thresholds developed in men to women, and we need as strong evidence for abdominal aortic aneurysm in women, as we have for men. We declare no competing interests. Morphological suitability for endovascular repair, non-intervention rates, and operative mortality in women and men assessed for intact abdominal aortic aneurysm repair: systematic reviews with meta-analysisCompared with men, a smaller proportion of women are eligible for EVAR, a higher proportion of women are not offered intervention, and operative mortality is much higher in women for both EVAR and open repair. The management of abdominal aortic aneurysm in women needs improvement. Full-Text PDF Open Access