Endovascular repair of abdominal aortic aneurysms outside manufacturer’s
instructions for use is associated with an unacceptable risk of proximal type I endoleak,
aneurysm-related and all-cause mortality, Jane Cross, University College Hospital,
London, UK, told delegates at the ESVS Annual Meeting.
“EVAR has revolutionised the management of infrarenal abdominal aortic aneurysms.
Suitability for EVAR is defined by anatomical criteria and approximately 25-50% of
aneurysms conform. Short and angulated aneurysm necks are associated with increased
endoleak and reintervention rate. Manufacturers have developed instructions for use
recommending minimum anatomical conditions for the use of their graft; these are produced
following extensive bench testing by engineers. Advances in technology, imaging, graft
design and operator experience has lead to an extension of the use of EVAR beyond initial
manufacturer’s guidelines,” Cross said. She stated that the options for endovascular repair of
aortic aneurysms with an adverse neck are “off-label” use of an infra-renal device or use of a
fenestrated endograft to extend the sealing zone proximal to the level of the renal arteries.
However fenestrated endografts are not universally available and at present there is limited
long-term evidence for their durability, she added.“Little data have been published on the
long term outcome of endografts inserted ‘off label’. It has been shown that use of EVAR
outside instructions for use was associated with a worse outcome that translated into patient
mortality in symptomatic abdominal aortic aneurysms. A recent study (Torsello et al) of the
use of Endurant stent grafts outside instructions for use showed an associated increase in type
I endoleak. However, numbers did not reach significance as the primary endpoint frequency
was low and study group small,” Cross said. Cross and colleagues conducted a review of the
EUROSTAR database of 11,208 cases to determine the long-term outcome of elective
infrarenal endografts inserted outside the manufacturers’ instructions for use. “We found a
significant association between the ‘off label’ use of endografts and increased all-cause
mortality and aneurysm related mortality at long term follow up. Although the grafts in our
study were older generation, we were able to determine a long follow-up of up to ten years.
These datasets support the fact that use of EVAR outside instructions for use can be done but
short term results that may appear satisfactory are in fact significantly worse in the long-term
follow-up,” she said. Cross told delegates that EVAR is an excellent prophylactic treatment
for infrarenal abdominal aortic aneurysm when undertaken correctly. “However, EVAR
appears less effective if outside instructions for use and increases the risk for long-term
failure. Long-term follow-up of EVAR has shown the early advantages of infrarenal EVAR
over open surgery disappear with time. The consequence of using ‘off-label’ stent grafts may
have resulted in steadily increased numbers of ruptured aneurysms. This has prompted our
unit to resort to a more liberal use of fenestrated stent grafts, given the excellent early results
with the latter,” she concluded.