Open repair of aortic aneurysms is associated with higher long-term survival in patients who fall outside the confines of endovascular aneurysm repair (EVAR) instructions for use (IFU), and should therefore be favored over EVAR among this cohort, the annual meeting of the New England Society for Vascular Surgery (NESVS) heard.
The finding was part of a study that showed treatment outside device-specific IFU—or off-label use of EVAR devices—is associated with adverse long-term outcomes. “Patients with aortic neck anatomy that falls outside of graft instructions use, or IFU, pose unique challenges,” the NESVS meeting was told Sept. 12. “Most data show that patients who undergo EVAR fair worse if their anatomy is outside the IFU.”
The research was conducted by a team of investigators at Massachusetts General Hospital in Boston, with the results delivered by Thomas F.X. O’Donnell, MD.
Their work looked to determine whether better options exist for patients excluded from the EVAR IFU. They pointed to a lack of well-documented evidence in favor of alternative modalities, and set out to compare standard EVAR with fenestrated EVAR and open repair. “One study found higher survival for open repair but did not take into account fitness for open repair and did not have a fenestrated arm,” O’Donnell noted.
The authors carried out a retrospective review of prospectively collected data from between 2010 and 2019 at their own institution. This included all elective infrarenal and juxtarenal abdominal aortic aneurysm (AAA) repairs.
The team studied three groups of patients: Those who underwent standard EVAR (474), those treated with FEVAR using the Cook Zenith device given it is the only commercially available fenestrated endograft (34), and patients received open repair (143).
“First, we compared results in patients treated with EVAR based on adherence to the IFU,” O’Donnell said. “Next we studied the cohort of patients outside the IFU, and compared results between treatment modalities. Not surprisingly, patients treated off-IFU were older, less often fit for open repair and had higher rates of comorbidities. Eleven different endografts were used during the study period. The most common IFU violation was inadequate neck length at 16%, followed by neck angle and width, each at 11%.”
Among EVAR patients, treatment outside the IFU was associated with almost six-fold higher adjusted rates for type 1a endoleaks (p=0.001) and more than two-fold higher long-term mortality (p=0.01).
“We then restricted our analysis to those patients with anatomy outside graft IFU,” O’Donnell continued. “Among patients outside the IFU, treatment with FEVAR was associated with significantly higher rates of reinterventions, while EVAR and open repair were similar. Perioperative mortality was 0.46% overall, with no difference between repair types.”
Long-term adjusted mortality, meanwhile, was found to be significantly lower in open repair patients compared to those who received both EVAR and the Zenith FEVAR.
“We then limited our analysis to patients deemed fit for open repair to avoid the confounding associated with patients with difficult anatomy undergoing EVAR simply because there was no other option,” O’Donnell explained. “We saw a similar trend here with higher mortality for [FEVAR] and a similar trend towards lower survival with EVAR. But that association was attenuated and no longer statistically significant.”
Concluding, O’Donnell stated: “In our study, treatment with EVAR outside the device-specific IFU at the aneurysm neck was associated with inferior long-term outcomes. Patients with adverse neck anatomy undergoing EVAR experienced higher rates of proximal endoleaks and mortality compared to those with suitable anatomy. Open repair appeared to be the most durable option for patients with anatomy outside the IFU, with lower mortality and reinterventions, compared to either EVAR or [FEVAR]. The three-vessel strategy of [FEVAR] does not appear to be the answer to difficult neck anatomy, although more study is needed to determine whether this is true of all FEVAR or whether significantly longer seal zones of four-vessel devices provide better results.”