Endovascular aneurysm sealing using the Nellix (Endologix) device in an acute setting “appears safe, feasible and concordant with the literature of endovascular aneurysm repair (EVAR),” according to a study published in the Journal of Endovascular Therapy.
The study found that Nellix—with its endovascular aneurysm sealing (EVAS) approach—achieved a 32% 30-day mortality rate in ruptured aneurysm patients, while 60% were treated outside the instructions for use. This is consistent with the results of other endovascular treatment trials, although the authors stress that “more robust prospective and comparative data are required to establish the position of the technique in the treatment algorithm of acute abdominal aortic aneurysms.”
Although elective EVAR is associated with a reduction in early mortality and morbidity, randomised trials have failed to show a survival benefit for endovascular strategies in the treatment of ruptured aneurysms. Thirty-day mortality rates of endovascular and open treatment for ruptured aneurysms are similar, but the IMPROVE trial indicated that endovascular treatment results in faster discharge with superior quality of life improvements and cost-effectiveness. A meta-analysis of the four existing ruptured aneurysm trials also shows a “consistent but non-significant trend toward lower mortality with endovascular treatment”. For these reasons, “endovascular repair may evolve as the preferred treatment for ruptured abdominal aortic aneurysms,” the authors of this study, led by Michel Reijnen (Rijnstate Hospital, Arnhem, The Netherlands), suggest.
In this study, the researchers were analysing the performance of the Nellix device and the associated EVAS technique in treating either ruptured or symptomatic abdominal aortic aneurysm. EVAS uses polymer-filled endobags to achieve sealing and anatomic fixation. A potential advantage of EVAS over EVAR for ruptured aneurysm repair is the ability to inflate the endobags of the Nellix system with saline (prefill) to achieve early haemostasis without losing limb perfusion, while a potential disadvantage of the technique is that the pressure of the endobags could increase the disruption.
This was a retrospective, multicentre, observational study conducted at eight centres (seven European and one in New Zealand). From February 2013 to April 2015, 58 patients (mean age 74±9 years and 46 of whom were men) with an acute aortic aneurysm were treated (28 ruptured and 30 symptomatic). The primary endpoint of the study was 30-day mortality and secondary endpoints included endoleak, reinterventions and 30-day morbidity.
Overall intensive care unit and hospital stay length were 2.2±6.6 days and 9.7±11.4 days, respectively. Thirty-day mortality rates were 32% (9/28) for the ruptured group and 7% (2/30) for the symptomatic group, with morbidity rates of 57% and 17%, respectively.
Early endoleak was present in only two (3%) patients, one in each group. Both leaks were type IA. Reinterventions within 30 days were performed in eight patients in the ruptured group. In the symptomatic patients, the only perioperative reintervention was the embolisation of a type IA endoleak. The mean follow-up was 9.3±3.1 months in the ruptured group and 12.4±5.4 months in the symptomatic group. The mean aneurysm diameter at 30-day follow-up was 71.8±16mm compared with 74.7±15.7mm preoperatively in the ruptured group and 66.1±13.5mm compared with 65.8±13mm in the symptomatic group.
Despite the promising results, “Obviously, more robust prospective data and, eventually, comparative trials with EVAR are required before considering the technique as standard of care,” the authors conclude. To this end, a prospective registry study is currently in development.
Speaking to Vascular News, Reijnen said that it was important to emphasise three key points from the study:
- These results were achieved by experienced Nellix users.
- Treatment protocols and bail-out strategies for EVAS in ruptured aneurysms are still in development
- No increase in wall disruption, due to the pressure-guided technique, was observed in the current series.