How do you stop an aneurysm before it bursts?
It is estimated that around 4 per cent of men aged between 65 and 74 in England have an abdominal aortic aneurysm - a swelling (aneurysm) of the main blood vessel that leads from the heart, down through the abdomen to the rest of the body (the aorta).
If a large aneurysm bursts, it causes huge internal bleeding and usually death; a burst aneurysm carries a 90 per cent death rate, making it the third most common cause of sudden death in the UK. If aneurysms are successfully repaired however, this prevents them blocking or bursting and there is a very high likelihood of a return to a normal life.
Endovascular repair (EVAR), involves inserting a graft within the aneurysm through small groin incisions, using X-rays to guide the graft into place. It can be carried out without general anaesthetic and with a very much shorter hospital stay in contrast to the traditional method of open repair, which imposes a significant period of recovery in intensive care.
What we did
The NIHR funded research to compare endovascular repair of Abdominal Aortic Aneurysm with the traditional open repair method.
Researchers recruited over 1400 patients to the study from across 38 UK hospitals. The key outcome was mortality, along with secondary measures like graft-related complications and reinterventions, adverse events, renal function, health-related quality of life and costs.
The timing of the trial was important to the NHS given the possibility that EVAR could disseminate widely and become the first choice procedure of UK clinicians in the absence of supporting evidence.
What we found
The results of EVAR found that in men fit for surgery, the 30 day mortality was less than half with EVAR compared to open repair. At four years, overall mortality was similar but aneurysm related deaths in the EVAR group were half that of the open repair group.
In men unfit for open repair,( those patients for whom EVAR was originally developed), there was no demonstrable benefit in terms of either mortality or quality of life. This unexpected finding showed that with high-risk patients, the emphasis should be on getting the patient fit for surgery rather than performing early EVAR.
The results of this study have made a major contribution to the rationale for and implementation of the NHS abdominal aortic aneurysms national screening programme.
The option of having EVAR and traditional open aneurysm repair means patients have increased choice, with patients tending to prefer EVAR as it offers faster discharge from hospital. Available registry data suggests that by 2012, EVAR was being used for 66.8% of cases for elective infra-renal repair by 2012, rising steadily from 62.1% in 2010 and 65.9% in 2011.
The NICE Interventional Procedure Guidance states that ‘Current evidence on the efficacy and short-term safety of stent–graft placement in abdominal aortic aneurysm appears adequate to support the use of this procedure’ (IPG 169, 2006). The guidance notes state: ‘The Interventional Procedures Advisory Committee reconsidered the procedure based on the results of a systematic review commissioned by NICE, following publication of the results of the (NIHR funded) EndoVascular Aneurysm Repair (EVAR) trials.’
The research has also been cited in international guidelines including those of the European Society for Vascular and Endovascular Surgery, the American Society for Vascular Surgery.