BSET-ConformabLe EndoVascular Aneurysm Repair (CLEVAR) registry v1.0
Research type
Research Study
Full title
The British Society of Endovascular Therapy ConformabLe EndoVascular Aneurysm Repair Registry
IRAS ID
260562
Contact name
Ruth Nicholson
Contact email
Sponsor organisation
Imperial College London
Clinicaltrials.gov Identifier
Duration of Study in the UK
2 years, 5 months, 30 days
Research summary
Research Summary
Abdominal aortic aneurysm (AAA) is a ballooning of the main blood vessel of the body that, untreated, leads to rupture. Endovascular aneurysm repair (EVAR), is a minimally invasive well-established treatment. A covered stent placed between the “neck”, above the aneurysm, and the iliac arteries excludes the aneurysm from flowing blood and prevents rupture. However, if the stent is not sealed at the neck the aneurysm is at risk of rupture, especially in cases with angulated necks. One novel EVAR device is the CE marked GORE® EXCLUDER® Conformable AAA Endoprosthesis with ACTIVE CONTROL System (EXCC). This device is an evolution of an established device allowing active shaping to conform to the specific patient aortic neck anatomy, with more accurate deployment, potentially greater neck coverage and better long term fixation/sealing. The primary aim of this study is to assess the degree of neck coverage by the EXCC device.
Patients with AAA who are suitable for EVAR and are being considered for treatment by EVAR at participating NHS hospitals, with experience in EVAR, are eligible for consideration for this study. Up to 200 participants will be recruited over 12 months, with a one-year follow-up. Clinical data and device specific outcomes will be prospectively collected for those undergoing routine clinical treatment of AAA by the EXCC device. Participants will not undergo any procedure that is not part of routine clinical care. Demographics, complications and re-interventions will be collected. Pre- and post-operative CT scans that are available will be analysed to determine the extent of neck coverage with the EXCC device.
The British Society of Endovascular Therapy (BSET) has received funds from the stent manufacturer (W.L. Gore & Associates, Inc.) to conduct study. BSET and the Sponsor (Imperial College London) have full responsibility for the design, conduct, analysis and reporting of this study.Summary of Results
A multi-centre, observational study for patients with abdominal aortic aneurysm (AAA) being considered for treatment or treated by endovascular aneurysm repair (EVAR).
What medical problem did the participants have?
An abdominal aortic aneurysm (AAA) is a ballooning of the main blood vessel (the aorta) that travels down through the tummy . An AAA can grow to a large size over time, and it may burst (rupture), causing life-threatening internal bleeding.What interventions did the participants receive?
The standard method to prevent the AAA from bursting is to re-line the aorta with an artificial piece of rigid tubing called a stent-graft that has been covered with material. This is inserted approach via a small cut in the groin to stop the aneurysm from expanding and restore normal diameter of the aorta. The graft is landed above the aneurysm in normal aorta below the arteries to the kidneys. This area is called the “aneurysm neck.” It is this area where the stent is sealed and the blood is prevented from flowing into the aneurysm sac. Similarly, the stent is landed and therefore sealed in the iliac arteries to the legs. The blood in the aneurysm around the stent is therefore excluded from the circulation, clots and the risk of rupture is dramatically lowered.
This is commonly known as a ‘keyhole’ or minimally invasive approach called EndoVascular (i.e. inside the aorta) Aneurysm Repair (EVAR).What happened during the study?
The BSET-CLEVAR) Registry, which was an observational study, collected data on a new design of an existing stent-graft called the “GORE EXCLUDER Conformable AAA Endoprosthesis with ACTIVE CONTROL” (also known as EXCC Device).
This new design allows the doctor to shape the upper end of the stent-graft so that it may be placed into the aorta more accurately, matching the shape of your aorta. The graft is also less rigid allowing it to “conform” to the anatomy of the aorta.Who participated in the study?
105 patients with AAA underwent EVAR at 13 UK hospitals participating in this study, which collected data about each patient’s treatment and progress for 12 months following EVAR, including review of up to two follow-up imaging scans that the patients received as part of routine surveillance after EVAR.What were the results of the study?
The study team calculated how accurate the new device was when placed into the aorta and estimated that, on average, only 9.1% of the aneurysm “neck” remained uncovered by the stent-graft. The more neck that is covered the greater the sealing area and, it is proposed, the better the long term result.
The shape of the aorta, specifically the angle of the aortic neck has important implications for the accurate and effective placement of the stent-graft. In patients with aortic anatomy that met instructions for use for the stent-graft, there was no difference in the percentage of aortic neck covered by the stent-graft regardless of the degree of aortic neck angulation. In addition, in these patients, there was a good seal at the top end of the stent with no leak (called a type 1a endoleak) at the end of the procedure. This suggests that the graft can be accurately placed even in patients with significant angulation of the aortic neck. By one year after EVAR, clinical outcomes remained acceptable, with no deaths from aortic disease.
In patients with challenging aortic anatomy where the aneurysm neck was very short or extremely angulated above 90 degrees (which is outside the instructions for use), there was more need for repositioning the stent-graft and carry out further surgical procedures. This group had lower technical success rates, therefore the study concluded that this stent-graft should only be used in patients with aortic anatomy that conforms to the instructions for use except in exceptional circumstances.
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Who carried out the research?
The British Society of Endovascular Therapy (BSET) initiated this study through its Council Members, which consists of Vascular Surgeons, and received funds from endograft manufacturer (W.L. Gore & Associates, Inc.) to carry out the study. The Study Coordination Centre is based at Imperial College London (the Sponsor). BSET and Imperial College London have overall full responsibility for the coordination and conduct of the study.THANK YOU to all the patients who participated in this study.
REC name
South East Scotland REC 01
REC reference
19/SS/0067
Date of REC Opinion
15 May 2019
REC opinion
Further Information Favourable Opinion