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Open and keyhole surgery for repairing a ruptured abdominal aortic aneurysm show similar rates of death at three months, though keyhole surgery leads to slightly shorter hospital stays. Women were found to benefit slightly more from the keyhole technique than men, according to this review and meta-analysis.

An abdominal aortic aneurysm is a swelling of the aorta – the body’s main artery. Large aneurysms are rare but if they burst there is catastrophic bleeding. The traditional treatment for abdominal aortic aneurysm is open repair: keyhole repair (also known as endovascular repair or EVAR) is a less invasive alternative method which is now commonly used.

Surgery can be performed to prevent rupture or after a rupture is detected. With similar outcomes the appropriate selection of patients for each procedure will remain important.

Longer term data and cost information are needed to inform clinical-decision making about whether a type of repair is preferable. Techniques for the procedure are likely to be continually getting better and future trials are likely to improve the evidence further.

Why was this study needed?

Small abdominal aortic aneurysms don’t usually pose a serious threat to health, but there is a risk larger aneurysms can rupture. They are most common in men over 65 years.

The evidence suggests that aneurysms expand at an average rate of 0.3 to 0.4 cm each year. The risk of rupture for aneurysms less than 4 cm across is less than 0.5% per year, but can rise to above 30% for aneurysms above 8 cm in diameter. Ruptured abdominal aortic aneurysms are one of the most common vascular emergencies. A ruptured aneurysm is nearly always fatal if not repaired. Ruptured abdominal aortic aneurysms account for more than 1 in 50 of all deaths in the over 65 age group and a total of 6,000 deaths in England and Wales each year.

There are two surgical techniques used to treat large aneurysms: open repair and endovascular repair (a type of keyhole surgery). See Definitions for more information.

The aim of the study was to determine if endovascular repair offers an improvement in patient survival up to 90 days or earlier hospital discharge compared to open repair. It also looked at any advantages for using endovascular repair for particular subgroups, such as for older patients, or for either men or women.

What did this study do?

This study performed meta-analyses of patient data from three different randomised controlled trials and had 836 participants in total. The three trials took place between 2004 and 2013 and were from The Netherlands, France and the largest, with 613 participants was conducted in the UK and Canada.

The study authors were mostly interested in the effects of the two different types of surgery on death rates following repair of ruptured abdominal aortic aneurysm after 90 days. This is because the three trials had previously only looked at death rates up to 30 days. Researchers from each trial collaborated to provide these longer term follow-up details.

Two of the original trials had the same design whilst the larger UK trial differed in study design and had more women, older participants and larger aneurysms. These factors and the likely changes in techniques over the years of the included studies reduce the reliability of the pooled results.

What did it find?

  • Rates of death at 30 and 90 days were similar for participants with ruptured abdominal aortic aneurysm treated with open surgery and endovascular repair. At 90 days 34.3% of participants treated with endovascular repair had died compared to 38.0% after open surgery (pooled odds ratio [OR] 0.85, 95% confidence interval [CI] 0.64 to 1.13).
  • Further analyses of these findings showed that women were almost twice as likely to benefit from endovascular repair as men (mortality up to 90-days was less, with the ratio of odds ratios, women compared to men, 0.49, 95% CI 0.24 to 0.99) but analysis by age and morbidity score at baseline did not have an effect on the findings.
  • Discharge from the hospital where the surgery took place was approximately 25% faster after endovascular repair than open repair (pooled hazard ratio 1.24, 95% CI 1.04 to 1.47).
  • There were mixed findings when looking at complications associated with abdominal aortic aneurysm repair.

What does current guidance say on this issue?

NICE’s 2009 technology appraisal Endovascular stent-grafts for the treatment of abdominal aortic aneurysms (TA 167) states that the decision on whether endovascular aneurysm repair is preferred over open surgical repair should be made jointly by the patient and clinician. This should be informed by clinical assessment of: the size and structure of the aneurysm; the patient’s age, life expectancy and fitness for surgery; and the short-and long-term benefits and risks of the procedures including aneurysm-related mortality and surgery-related mortality. This appraisal does not recommend endovascular repair for ruptured aneurysms unless conducted as part of a clinical trial.

A NICE clinical guideline, Abdominal aortic aneurysm: diagnosis and management, currently in progress and due for publication in October 2017, is set to replace the 2009 technology appraisal.

What are the implications?

This review found that outcomes were similar (including survival up to 30 and 90 days) for patients who were treated with endovascular repair compared to open repair for ruptured abdominal aortic aneurysm. Women were found to benefit slightly more from endovascular repair than men, but reasons for this were uncertain. Patients were on average discharged sooner after endovascular repair than open repair.

This study looked at rates of death up to 90 days. Longer-term rates of death are needed to inform clinical-decision making about whether a type of repair is preferable.

In terms of hospital resources, endovascular repair requires the patient to be treated in the radiology suite whilst open repair requires time spent in the operating theatre. This study did not consider these factors or include a cost-effectiveness comparison between the types of procedures.

 

Citation and Funding

Sweeting MJ, Balm R, Desgranges P, et al; Ruptured Aneurysm Trialists. Individual-patient meta-analysis of three randomized trials comparing  endovascular versus open repair for ruptured abdominal aortic aneurysm. Br J Surg. 2015;102(10):1229-39.

This project was funded by the National Institute for Health Research Health Technology Assessment programme (project number 07/37/64).

 

Bibliography

IMPROVE Trial Investigators. Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial. BMJ. 2014;348:f7661.

NHS Choices. Abdominal aortic aneurysm [internet].Leeds: NHS Choices; 2014.

NICE. Endovascular stent-grafts for the treatment of abdominal aortic aneurysms. TA 167. London: National Institute for Health and Care Excellence; 2009.

NICE clinical guideline (in progress). Abdominal aortic aneurysm: diagnosis and management. London. National Institute for Health and Care Excellence. Anticipated publication date: October 2017.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

 


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Definitions

NHS Choices defines the surgical techniques as:

  • open repair – involves a cut to the stomach to reach the abdominal aorta where the enlarged section is replaced with a graft
  • endovascular repair – a type of keyhole surgery where the surgeon guides a small graft up through the leg artery from the groin.

More information about these types of surgeries can be found at NHS Choices.

Hardman index is a validated morbidity score for ruptured aneurysm.

 

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