Condition category
Circulatory System
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Ruptured abdominal aortic aneurysm is a life-threatening condition where the main blood vessel of the body (the aorta) has swollen over many years (often silent with no obvious symptoms) and burst, causing extensive bleeding. Many patients with this condition do not survive to reach hospital alive. Until recently there was only one way to repair the ruptured aneurysm. This involved major surgery with a large cut in the tummy and replacement of the diseased aorta with a plastic (Polyester) tube (open surgery). However, after this major emergency surgery only about half of the patients leave hospital alive. A new 'keyhole' technique of aneurysm repair, called endovascular repair, has made it possible to re-line the ruptured aorta using a stent introduced through two small cuts in the groin (endovascular repair). However, only about 60% of patients are anatomically suitable for endovascular repair. At present we do not know which of the treatments is best for people with this condition. Therefore, this study aims to find out whether a strategy of preferential emergency endovascular repair reduces both the mortality (death rate) and cost of ruptured abdominal aortic aneurysm.

Who can participate?
Men and women, over the age of 50 years, who are suspected of having ruptured abdominal aortic aneurysm after review in Accident and Emergency (or other hospital unit) are eligible to participate in the trial.

What does the study involve?
Participants will be randomly allocated, in the emergency room, to either a strategy of endovascular repair if possible (endovascular strategy) or to the current standard care (immediate transfer to the operating theatre for emergency open surgery). Patients allocated to the endovascular strategy will require a special X-ray scan (CT scan) to assess anatomical suitability and plan for endovascular repair. This will cause a short delay before definitive repair can begin: the study will find out whether this delay is dangerous. Those patients not suitable for endovascular repair after CT scan will be taken for standard open surgery and the others will have endovascular repair. We shall measure participants' survival within 30 days of surgery, which we hope will improve by 14% with the endovascular strategy. We shall also measure survival at hospital discharge and after 12 months, the costs of each treatment, quality of life and cost-effectiveness. We hope that these will improve with endovascular repair.

What are the possible benefits and risks of participating?
Ruptured abdominal aortic aneurysm is an immediately life-threatening condition. Without an operation patients do not survive. Consequently, operations to save patients' lives are associated with major complications. However, it is very unlikely that research participants will suffer any additional pain, discomfort, distress or inconvenience beyond patients not participating in the research. Patients who have received an endovascular repair will continue to be monitored for device complications under standard NHS care.

Where is the study run from?
The study co-ordinating centre is based at the Vascular Surgery Research Group, Imperial College London. The trial will be conducted in about 20 specialist hospital centres in the UK (and one large centre in Canada), which have already attained sufficient experience in using endovascular repair for ruptured aneurysms and can offer a routine service of emergency endovascular repair.

When is the study starting and how long is it expected to run for?
The trial will start recruiting patients in September 2009 and finish recruitment in July 2013. Patient follow-up will continue until July 2016.

Who is funding the study?
This research is supported by the UK National Institute for Health Research Health Technology Assessment Programme and managed through Imperial College London.

Who is the main contact?
Professor Janet Powell,
Dr Pinar Ulug, IMPROVE trial manager,

Trial website

Contact information



Primary contact

Prof Janet Powell


Contact details

Vascular Surgery Research Group
Imperial College London
Charing Cross Campus
St Dunstans Road
W6 8RP
United Kingdom
+44 (0)20 8846 7312

Additional identifiers

EudraCT number number


Protocol/serial number

HTA 07/37/64

Study information

Scientific title

Can emergency endovascular aneurysm repair (eEVAR) reduce mortality from ruptured abdominal aortic aneurysm (AAA)?



Study hypothesis

Ruptured abdominal aortic aneurysm is the bursting of the main blood vessel of the body (the aorta) in the belly, which causes death in over 85% of cases. An attempt at open surgical repair is made in less than half of those who arrive at hospital alive and of those receiving surgical repair only half will be alive at 30 days.

It is possible that application of new minimally invasive technology (endovascular aneurysm repair [EVAR]) would greatly improve the number of patients alive at 30 days. However not all patients are anatomically suitable for endovascular repair.

The principal research question is, to be addressed in a randomised clinical trial is:
Can a strategy of preferential endovascular repair of ruptured abdominal aortic aneurysm, versus the current practice of open surgical repair, significantly reduce the 30 day mortality of this condition?

More details can be found at:
Protocol can be found at:

On 10/02/2014 the following changes were made to the trial record:
1. Canada was added to the countries of recruitment
2. The overall trial end date was changed from 31/03/2013 to 31/12/2016

Ethics approval

1. South Central - Berkshire Research Ethics Committee, 22/12/2008, ref: 08/H0505/173
2. Scotland A Research Ethics Committee, 19/12/2008, ref: 08/MRE00/90
3. University of Western Ontario Health Sciences Research Ethics Board (HSREB), 14/06/2011, Review No: 17698

Study design

Randomised controlled multi-centre trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Patient information can be found at:


Abdominal aortic aneurysm


The patients will be randomised to a strategy of EVAR if anatomically suitable (EVAR first) or to the standard emergency open surgery.

Intervention type



Drug names

Primary outcome measures

30-day mortality

Secondary outcome measures

As of 18/08/2016:
1. Mortality at 24-hour, in-hospital, and 1-year and 3-years after the rupture
2. Complications and re-interventions related to ruptured AAA repair in 1 year and 3 years
3. Major morbidity (stroke, myocardial infarction, renal or respiratory failure) in 1 year
4. Accuracy of clinical diagnosis of ruptured abdominal aortic aneurysm
5. Cost and Cost-effectiveness

1. Mortality at 24-hour, in-hospital, and 1-year after the rupture
2. Complications and re-interventions related to ruptured AAA repair in 1 year
3. Major morbidity (stroke, myocardial infarction, renal or respiratory failure) in 1 year
4. Accuracy of clinical diagnosis of ruptured abdominal aortic aneurysm
5. Cost-effectiveness

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Both males and females, over the age of 50 years
2. Clinical suspicion of ruptured abdominal aortic aneurysm after review in Accident and Emergency (or other hospital unit)

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Patients with known connective tissue disorders (e.g., Marfan syndrome) where endovascular repair may not be beneficial
2. Patients with known previous repair of an abdominal aortic aneurysm, because procedures either open or endovascular are likely to be very complex and there are no guidelines for anatomical restriction to repair
3. Deeply unconscious and moribund patients since the chances of recovery are minimal

Recruitment start date


Recruitment end date



Countries of recruitment

Canada, United Kingdom

Trial participating centre

Imperial College London
W6 8RP
United Kingdom

Sponsor information


Imperial College London (UK)

Sponsor details

Research Governance Office
Faculty of Medicine
G02 Sir Alexander Flemming Building
South Kensington Campus
United Kingdom

Sponsor type




Funder type


Funder name

NIHR Health Technology Assessment Programme - HTA (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Publications and reporting is expected in early 2014 (short-term results) and 2017 (long-term results).

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

2009 protocol in:
2009 protocol in:
2014 results in:
2014 results in:
2014 results in:
2015 results in:
2015 results in:
2015 results in:
2915 resuits in:

Publication citations

  1. Protocol

    Powell JT, Thompson SG, Thompson MM, Grieve R, Nicholson AA, Ashleigh R, Hassan T, Moore F, Walker A, Braithwaite BD, Hinchliffe RJ, Greenhalgh RM, Cheshire NJ, Howell SJ, Soong CV, The Immediate Management of the Patient with Rupture: Open Versus Endovascular repair (IMPROVE) aneurysm trial--ISRCTN 48334791 IMPROVE trialists., Acta Chir. Belg., 109, 6, 678-680.

  2. Results

    Powell JT, Sweeting MJ, Thompson MM, Ashleigh R, Bell R, Gomes M, Greenhalgh RM, Grieve R, Heatley F, Hinchliffe RJ, Thompson SG, Ulug P, Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial., BMJ, 2014, 348, f7661.

  3. Results

    Powell JT, Hinchliffe RJ, Thompson MM, Sweeting MJ, Ashleigh R, Bell R, Gomes M, Greenhalgh RM, Grieve RJ, Heatley F, Thompson SG, Ulug P, Observations from the IMPROVE trial concerning the clinical care of patients with ruptured abdominal aortic aneurysm., Br J Surg, 2014, 101, 3, 216-24; discussion 224, doi: 10.1002/bjs.9410.

  4. Results

    An endovascular strategy for suspected ruptured abdominal aortic aneurysm brings earlier home discharge but not early survival or cost benefits., Eur J Vasc Endovasc Surg, 2014, 47, 4, 333-334, doi: 10.1016/j.ejvs.2013.12.017.

  5. Powell JT, Time to IMPROVE the management of ruptured abdominal aortic aneurysm: IMPROVE trialists., Eur J Vasc Endovasc Surg, 2009, 38, 2, 237-238, doi: 10.1016/j.ejvs.2009.04.002.

  6. Results

    IMPROVE Trial Investigators, The effect of aortic morphology on peri-operative mortality of ruptured abdominal aortic aneurysm, Eur Heart J, 2015, doi: 10.1093/eurheartj/ehu521.

  7. Results

    Grieve R, Gomes M, Sweeting MJ, Ulug P, Hinchliffe RJ, Thompson MM, Thompson SG, Ashleigh R, Greenhalgh RM, Powell JT; IMPROVE trial investigators, Endovascular strategy or open repair for ruptured abdominal aortic aneurysm: one-year outcomes from the IMPROVE randomized trial, Eur Heart J, 2015, doi: 10.1093/eurheartj/ehv125.

Additional files

Editorial Notes

30/09/2016: Added publication references 18/08/2016: Made amendments to secondary outcome measures (time stamped in record), added ORCID for study contact