EXCC Device Shows Safety, Efficacy for Angulated Aortic Necks at One Year

Navigating Complex Aortic Anatomy in Endovascular Aneurysm Repair

Endovascular aneurysm repair (EVAR) has become a mainstay in the management of abdominal aortic aneurysms (AAAs), offering a less invasive alternative to open surgery with established short-term survival benefits [1, 2, 3]. However, the long-term durability of EVAR can be compromised by anatomical factors, often necessitating reinterventions [4, 5]. The morphology of the proximal aortic neck is a critical determinant of procedural success [6, 7]. A severely angulated infrarenal neck, in particular, complicates stent graft placement and increases the risk of type Ia endoleaks, where an inadequate seal allows persistent blood flow into the aneurysm sac. This complication, along with stent graft migration, can lead to aneurysm expansion and potential rupture [6, 8, 9]. In response, manufacturers have engineered devices specifically to address these hostile anatomies [10]. A recent multicenter registry provides real-world data on the performance of one such endoprosthesis in this challenging patient population.

Evaluating the EXCC Device in Challenging Anatomy

A new study from the EXTREME registry (EXcluder Conformable endoprosThesis foR angulatEd proxiMal nEck anatomy) evaluated the performance of a specific device in patients with difficult aortic anatomy. The research focused on the Gore Excluder conformable abdominal aortic aneurysm endoprosthesis with ACTIVE CONTROL System (EXCC), an endograft designed by W.L. Gore & Associates (Flagstaff, AZ) for use in AAAs with a challenging proximal neck. Its conformable design allows it to adapt to tortuous vessels, while the ACTIVE CONTROL deployment system is intended to facilitate more precise placement. The retrospective analysis, conducted across 23 Japanese institutions, assessed all EVAR procedures using the EXCC device within the registry. The primary endpoint was freedom from late complications, a composite measure including aneurysm-related death, any reintervention, or aneurysm sac enlargement greater than 5 mm occurring more than 30 days postoperatively. Secondary endpoints provided a fuller picture, tracking intraoperative adverse events, endoleaks, and changes in aneurysm size.

Patient Cohort and Initial Procedural Outcomes

The EXTREME registry enrolled a total of 215 patients. To isolate the impact of difficult anatomy, the researchers stratified the cohort based on the angle of the proximal infrarenal neck, a common metric for procedural complexity. The angulated neck group included 109 patients with an angle greater than 60°, a threshold often used to define a hostile neck. The non-angulated group consisted of 106 patients with a neck angle of 60° or less. This design allowed for a direct comparison of the device's performance in both straightforward and anatomically demanding scenarios. Initial outcomes were comparable between the two groups. The technical success rate was high in both cohorts, at 93.5% in the angulated group and 94.3% in the non-angulated group (P = 0.81). The incidence of intraoperative major adverse events was also similarly low, at 1.8% and 0.9% respectively (P = 0.54). A key concern in angulated necks is achieving an adequate proximal seal. At the final intraoperative aortogram, the incidence of type 1a endoleak was 5.5% in the angulated group versus 1.8% in the non-angulated group (P = 0.16). On subsequent in-hospital computed tomography (CT) scans, the rate of type 1a endoleak was 3.6% in the angulated group and 0% in the non-angulated group (P = 0.12). While numerically higher in the angulated cohort, these differences in early endoleak rates did not reach statistical significance.

One-Year Clinical Durability and Reintervention Rates

To assess mid-term performance, the study followed patients for a mean of 404 ± 190 days, providing crucial data beyond the immediate perioperative period. The need for reintervention is a primary indicator of an endograft's durability. The analysis revealed that freedom from reintervention was high and nearly identical in both cohorts. In the angulated neck group, the rate was 98.9% at 6 months and 96.6% at 12 months. For the non-angulated neck group, the rates were 99.0% at 6 months and 95.7% at 12 months. A log-rank test comparing the two groups over the follow-up period yielded a P-value of 0.99, confirming no statistically significant difference in the need for reintervention between patients with and without challenging neck angulation at one year. This suggests that the device's structural integrity and placement remain stable in both anatomical settings through the first year.

Late Complication Profile at One Year

The study's primary endpoint, freedom from late complications, provides the most comprehensive assessment of the device's overall safety and effectiveness. This composite measure captures not only reinterventions but also aneurysm-related mortality and significant aneurysm sac growth, which signals treatment failure. The results for this endpoint were robust across both patient groups. In the angulated neck group, freedom from late complications was 99.0% at 6 months and 96.6% at 12 months. The non-angulated group showed nearly identical outcomes, with rates of 99.0% at 6 months and 95.8% at 12 months. The statistical comparison of these outcomes yielded a log-rank P-value of 0.63, demonstrating no significant difference in the rate of late complications at one year between patients treated in highly angulated versus less angulated aortic necks. These data indicate that the EXCC device provides a consistent safety and efficacy profile during the first year, irrespective of this specific anatomical challenge.

Clinical Implications and Future Directions

The findings from the EXTREME registry offer valuable guidance for clinicians performing EVAR in patients with complex aortic anatomy. The study provides evidence for the safety and efficacy of the EXCC device in patients with a proximal neck angle greater than 60°, a cohort that can be difficult to treat endovascularly. The device achieved outcomes comparable to those seen in patients with more favorable anatomy over a one-year period. For physicians, a critical takeaway is the device's performance regarding type 1a endoleaks, which represent a failure to exclude the aneurysm from circulation. The low incidence of type 1a endoleak, even in the angulated group, suggests effective proximal sealing is achievable with this technology. The comparable freedom from late complications at 12 months (96.6% in the angulated group vs. 95.8% in the non-angulated group; log-rank P = 0.63) supports the consideration of the EXCC device for patients who might otherwise be considered poor candidates for standard EVAR. The authors appropriately caution, however, that long-term follow-up is necessary to confirm the durability of these results. Continued surveillance beyond one year will be essential to fully establish the device's performance under the sustained hemodynamic stress associated with hostile neck anatomy.

References

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