The Impact of Centralisation and Endovascular Aneurysm Repair on Treatment of Ruptured Abdominal Aortic Aneurysms Based on International Registries


Current management of ruptured abdominal aortic aneurysms (RAAA) varies among centres and countries, particularly in the degree of implementation of endovascular aneurysm repair (EVAR) and levels of vascular surgery centralisation. This study assesses these variations and the impact they have on outcomes.

Materials and methods

RAAA repairs from vascular surgical registries in 11 countries, 2010–2013, were investigated. Data were analysed overall, per country, per treatment modality (EVAR or open aortic repair [OAR]), centre volume (quintiles I V), and whether centres were predominantly EVAR (≥50% of RAAA performed with EVAR [EVAR(p)]) or predominantly OAR [OAR(p)]. Primary outcome was peri-operative mortality. Data are presented as either mean values or percentages with 95% CI within parentheses, and compared with chi-square tests, as well as with adjusted OR.


There were 9273 patients included. Mean age was 74.7 (74.5–74.9) years, and 82.7% of patients were men (81.9–83.6). Mean AAA diameter at rupture was 7.6 cm (7.5–7.6). Of these aneurysms, 10.7% (10.0–11.4) were less than 5.5 cm. EVAR was performed in 23.1% (22.3–24.0). There were 6817 procedures performed in OAR(p) centres and 1217 performed in EVAR(p) centres. Overall peri-operative mortality was 28.8% (27.9–29.8). Peri-operative mortality for OAR was 32.1% (31.0–33.2) and for EVAR 17.9% (16.3–19.6), p < .001, and the adjusted OR was 0.38 (0.31–0.47), p < .001. The peri-operative mortality was 23.0% in EVAR(p) centres (20.6–25.4), 29.7% in OAR(p) centres (28.6–30.8), p < .001; adjusted OR = 0.60 (0.46–0.78), p < .001. Peri-operative mortality was lower in the highest volume centres (QI > 22 repairs per year), 23.3% (21.2–25.4) than in QII-V, 30.0% (28.9–31.1), p < .001. Peri-operative mortality after OAR was lower in high volume centres compared with the other centres, 25.3% (23.0–27.6) and 34.0% (32.7–35.4), respectively, p < .001. There was no significant difference in peri-operative mortality after EVAR between centres based on volume.


Peri-operative mortality is lower in centres with a primary EVAR approach or with high case volume. Most repairs, however, are still performed in low volume centres and in centres with a primary OAR strategy. Reorganisation of acute vascular surgical services may improve outcomes of RAAA repair.



Assessment of International Outcomes of Intact Abdominal Aortic Aneurysm Repair over 9 Years


Case mix and outcomes of complex surgical procedures vary over time and between regions. This study analyses peri-operative mortality after intact abdominal aortic aneurysm (AAA) repair in 11 countries over 9 years.


Data on primary AAA repair from vascular surgery registries in 11 countries for the years 2005-2009 and 2010-2013 were analysed. Multivariate adjusted logistic regression analyses were carried out to adjust for variations in case mix.


A total of 83,253 patients were included. Over the two periods, the proportion of patients ≥80 years old increased (18.5% vs. 23.1%; p < .0001) as did the proportion of endovascular repair (EVAR) (44.3% vs. 60.6; p < .0001). In the latter period, 25.8% of AAAs were less than 5.5 cm. The mean annual volume of open repairs per centre decreased from 12.9 to 10.6 between the two periods (p < .0001), and it increased for EVAR from 10.0 to 17.1 (p < .0001). Overall, peri-operative mortality fell from 3.0% to 2.4% (p < .0001). Mortality for EVAR decreased from 1.5% to 1.1% (p < .0001), but the outcome worsened for open repair from 3.9% to 4.4% (p = .008). The peri-operative risk was greater for octogenarians (overall, 3.6% vs. 2.1%, p < .0001; open, 9.5% vs. 3.6%, p < .0001; EVAR, 1.8% vs. 0.7%, p < .0001), and women (overall, 3.8% vs. 2.2%, p < .0001; open, 6.0% vs. 4.0%, p < .0001; EVAR, 1.9% vs. 0.9%, p < .0001). Peri-operative mortality after repair of AAAs <5.5 cm was 4.4% with open repair and 1.0% with EVAR, p < .0001.


In this large international cohort, total peri-operative mortality continues to fall for the treatment of intact AAAs. The number of EVAR procedures now exceeds open procedures. Mortality after EVAR has decreased, but mortality for open operations has increased. The peri-operative mortality for small AAA treatment, particularly open surgical repair, is still considerable and should be weighed against the risk of rupture.


Variations in Abdominal Aortic Aneurysm Care: A Report From the International Consortium of Vascular Registries


This project by the ICVR (International Consortium of Vascular Registries), a collaboration of 11 vascular surgical quality registries, was designed to evaluate international variation in the contemporary management of abdominal aortic aneurysm (AAA) with relation to recommended treatment guidelines from the Society for Vascular Surgery and the European Society for Vascular Surgery.


Registry data for open and endovascular AAA repair (EVAR) during 2010 to 2013 were collected from 11 countries. Variations in patient selection and treatment were compared across countries and across centers within countries.


Among 51 153 patients, 86% were treated for intact AAA (iAAA) and 14% for ruptured AAA. Women constituted 18% of the entire cohort (range, 12% in Switzerland-21% in the United States; P<0.01). Intact AAAs were repaired at diameters smaller than recommended by guidelines in 31% of men (<5.5 cm; range, 6% in Iceland-41% in Germany; P<0.01) and 12% of women with iAAA (<5 cm; range, 0% in Iceland-16% in the United States; P<0.01). Overall, use of EVAR for iAAA varied from 28% in Hungary to 79% in the United States (P<0.01) and for ruptured AAA from 5% in Denmark to 52% in the United States (P<0.01). In addition to the between-country variations, significant variations were present between centers in each country in terms of EVAR use and rate of small AAA repair. Countries that more frequently treated small AAAs tended to use EVAR more frequently (trend: correlation coefficient, 0.51; P=0.14). Octogenarians made up 23% of all patients, ranging from 12% in Hungary to 29% in Australia (P<0.01). In countries with a fee-for-service reimbursement system (Australia, Germany, Switzerland, and the United States), the proportions of small AAA (33%) and octogenarians undergoing iAAA repair (25%) were higher compared with countries with a population-based reimbursement model (small AAA repair, 16%; octogenarians, 18%; P<0.01). In general, center-level variation within countries in the management of AAA was as important as variation between countries.


Despite homogeneous guidelines from professional societies, significant variation exists in the management of AAA, most notably for iAAA diameter at repair, use of EVAR, and the treatment of elderly patients. ICVR provides an opportunity to study treatment variation across countries and to encourage optimal practice by sharing these results.


Regional Differences in Case Mix and Peri-operative Outcome After Elective Abdominal Aortic Aneurysm Repair in the Vascunet Database


National differences exist in the outcome of elective abdominal aortic aneurysm (AAA) repair. The role of case mix variation was assessed based on an international vascular registry collaboration.


All elective AAA repairs with aneurysm size data in the Vascunet database in the period 2005-09 were included. AAA size and peri-operative outcome (crude and age adjusted mortality) were analysed overall and in risk cohorts, as well as per country. Glasgow Aneurysm Score (GAS) was calculated as risk score, and patients were stratified in three equal sized risk cohorts based on GAS. Predictors of peri-operative mortality were analysed with multiple regression. Missing data were handled with multiple imputation.


Patients from Australia, Finland, Hungary, Norway, Sweden and the UK (n = 5,895) were analysed; mean age was 72.7 years and 54% had endovascular repair (EVAR). There were significant variations in GAS (lowest = Finland [75.7], highest = UK [79.4], p for comparison of all regions < .001), proportion of AAA < 5.5 cm (lowest = UK [6.4%], highest = Hungary [29.0%]; p < .001), proportion undergoing EVAR (lowest = Finland [10.1%], highest = Australia [58.9%]; p < .001), crude mortality (lowest = Norway [2.0%], highest = Finland [5.0%]; p = .006), and age adjusted mortality (lowest = Norway [2.5%], highest = Finland [6.0%]; p = .048). Both aneurysm size and peri-operative mortality were highest among patients with a GAS >82. Of those with a GAS >82, 8.4% of men and 20.8% of women had an AAA <5.5 cm.


Important regional differences exist in case selection for elective AAA repair, including variations in AAA size and patient risk profile. These differences partly explain the variations in peri-operative mortality. Further audit is warranted to assess the underlying reasons for the regional variation in case-mix.


Quality Improvement in Vascular Surgery: The Role of Comparative Audit and Vascunet

Most nations with developed healthcare systems have a strong interest in audit, both for financial and clinical quality control. Whereas financial control has been a key political requirement for managing healthcare, the use of clinical outcome data has, until recently, taken more of a back seat.

Clinical audit has a long history of describing outcomes and challenging established attitudes or practice.1 Responses to published audits vary. Some clinicians voice criticism of bias as a result of selective reporting, either from a few units, or because of incomplete datasets.2 Attitudes have gradually changed with improved understanding of the role of audit as a tool to examine and refine standards of practice.3 This has been accompanied by a growth in clinical audit across all branches of medicine.

The turn of the century marked a shift towards more widespread clinical audit, with development of political interest in using quality to justify or contain costs. The advent of organisations such as the National Institute for Clinical Excellence (NICE) in the UK saw a growth in the use of research and audit to set standards both for outcomes and processes of care. A good example of this in vascular surgery is the NICE clinical guideline 68, which sets out clear standards for assessment, referral, and treatment of patients with TIA and minor stroke.4 These standards are incorporated into national audits in Europe and reporting now encompasses both outcomes and performance indicators such as timeliness of surgery and cranial nerve injury.5 Such reporting has driven improvement in quality of services by focussing clinicians on key components of high-quality pathways of care.

Vascunet was formed in 1997 as a collaboration of national registries in Europe, New Zealand, and the state of Victoria in Australia, with its first report produced in 2007.6, 7 Since then, the Vascunet group have published comparative data on carotid surgery,8, 9 abdominal aortic aneurysm,10 lower limb bypass,11 and popliteal artery aneurysm.12 One of the key features of these publications has been to describe the variation in clinical practice across neighbouring countries, notable examples being rates of surgery for asymptomatic stenosis and rates of lower limb bypass for intermittent claudication. Variation in outcomes is also reported at a national level.

The value of such reporting was demonstrated by the 2008 Vascunet report. This demonstrated outlying mortality rates after elective repair of abdominal aortic aneurysm surgery in the UK.13 This was a stimulus to a quality improvement initiative14 that sought to standardise practice and improve outcomes. The transparent publication of standards led to their widespread adoption both by clinicians and service commissioners within the UK. Recent publications have demonstrated a marked improvement in UK outcomes.15 This cycle of audit, analysis, standard setting, and re-audit demonstrates the improvement in quality that can follow acknowledgement of poor outcomes. This experience mirrors those in other clinical specialities such as cardiothoracic surgery.

Comparative audits suffer from a number of shortcomings, such as incomplete datasets with potential for bias and misleading interpretation. Most national registries rely on voluntary data contributions from practising clinicians who have varying levels of enthusiasm for audit. It is widely acknowledged that incomplete audit data is a source of bias and may give misleading messages. This has allowed some to ignore the messages from comparative audit, and may be the explanation behind some countries not wishing to participate in data analysis and publication. The recognition of this issue leads to the linking of Swedvasc (and the Helsinki datasets in Finland) data to national administrative datasets to improve accuracy. Similarly in the UK, data for carotid and aortic aneurysm procedures are now compared with national administrative datasets to demonstrate the quality of data. A secondary benefit has been an improvement in data quality, presumably as a result of peer pressure.

Vascunet has recently taken this further with external validation of data subsets in Hungary 16 and Sweden (ongoing project). This pilot demonstrated that national datasets can be validated by expatriate experts, providing an independent and even more robust measure of data quality. It is planned to extend this throughout the Vascunet registries group, if funding can be found.

Clinical audit data is one important source of information, about routine clinical practice, that can be used to highlight inconsistencies in clinical outcomes. The use of data, however incomplete, as an agent for change and as a guide for standard setting is established. We believe that the use of national audit data should be extended to drive quality improvement across geographical boundaries.

There are significant challenges to achieving this, but Vascunet believes that the time is right to embrace this. With increasing financial constraints on healthcare, clinicians need to be seen to lead on issues of quality of care. Part of this requires an open approach to measuring the standards of care, with the aim of improvement, rather than criticism. We believe that we have the support of patients in this aim and that transparent publication of data serves to both inform and educate in the debate about allocation of limited resources.

There is debate about what and how much data should be collected. Most enthusiasts approach clinical audit wishing to obtain a large amount of data to enable a detailed analysis of behaviour. The problem with this approach is that it inevitably relies on busy clinicians collecting the data, often after delivery of care. Unsurprisingly, the levels of enthusiasm for this vary hugely, with some seeing it as an intrusion on their relationship with the patient. The end result is incomplete and unreliable datasets and limited reporting.

An alternative is to collect small amounts of data about critical steps in the patient pathway of care. Such “key performance indicators” (KPI) can be linked to nationally collected administrative data to provide a moderately detailed account of the process of care. An example of this is seeking both outcome data (stroke and death) following carotid endarterectomy and collecting data on symptom to treatment time, to provide a more balanced picture of the quality of care. The resultant “less is more” approach allows for small datasets to provide important information to clinicians.

A number of factors determine how effective clinical audit is at changing clinician behaviours and patient outcomes. There is now a growing science around audit and feedback.17, 18 This states some factors that seem self-evident. For example there is evidence that audit and feedback can be made more effective by setting explicit goals and having a clear and realistic action plan, based on evidence about best practice. There needs to be clarity about the changes required and a commitment to multiple feedback cycles, with availability of peer group data for comparison. Repeated feedback delivered in both written and verbal format by people perceived to be part of the clinical team (i.e. part of the professional group) is much more effective in bringing about change than delivery by outside agencies (e.g. departments of health, commissioners of care). We believe that Vascunet can fill this role as it is made up of representatives from all participating audits.

Open reporting of data in a manner designed to support and encourage change, can be used to drive quality improvement by focussing on a small number of measures associated with a quality service. This has now been happening in many countries for some years. This approach has been used successfully for some years in Sweden, the UK and parts of the USA to demonstrate the quality of service and drive up standards by placing this in the public domain. The focus has been on care delivery within each country. We believe that the next step is for outcomes data analysis and quality improvement in vascular surgery to cross national boundaries, by common reporting of KPI for core vascular procedures. This is why Vascunet has begun validating national registries and has formed links with the North American Society of Vascular Surgery Quality Initiative (SVS-QI).

What is now required is clinical support to agree that it is in both our and our patients’ best interests to support a broadening of clinical audit to provide quality feedback across Europe. This will involve defining agreed datasets and seeking financial support to set up a data centre for analysis and reporting. Data collection should remain a local activity, owned by units and national societies, each committed to collaboration within the Vascunet group. We believe that the time is ripe to use the European registry experience to develop quality improvement initiatives throughout the European society nations and share our experiences openly to the benefit of our patients and clinical practices.


Treatment of abdominal aortic aneurysm in nine countries 2005-2009: a vascunet report


To study contemporary treatment and outcome of abdominal aortic aneurysm (AAA) repair in nine countries.


Data on primary AAA repairs 2005-2009 were amalgamated from national and regional vascular registries in Australia, Denmark, Finland, Hungary, Italy, Norway, Sweden, Switzerland and the UK. Primary outcome was in-hospital or 30-day mortality. Multivariate logistic regression was used to assess case-mix.


31,427 intact AAA repairs were identified, mean age 72.6 years (95% CI 72.5-72.7). The rate of octogenarians and use of endovascular repair (EVAR) increased over time (p < 0.001). EVAR varied between countries from 14.7% (Finland) to 56.0% (Australia). Overall perioperative mortality after intact AAA repair was 2.8% (2.6-3.0) and was stable over time. The perioperative mortality rate varied from 1.6% (1.3-1.8) in Italy to 4.1% (2.4-7.0) in Finland. Increasing age, open repair and presence of comorbidities were associated with outcome. 7040 ruptured AAA repairs were identified, mean age 73.8 (73.6-74.0). The overall perioperative mortality was 31.6% (30.6-32.8), and decreased over time (p = 0.004).


The rate of AAA repair in octogenarians as well as EVAR increased over time. Perioperative outcome after intact AAA repair was stable over time, but improved after ruptured repair. Geographical differences in treatment of AAA remain.