Sac Shrinkage in EVAR: How Important Is It?

During Tuesday's Aortic Update session, Dr. Marc Schermerhorn from Harvard Medical School and Beth Israel Deaconess Medical Center in Boston, Massachusetts, gave a presentation on sac shrinkage in endovascular aneurysm repair (EVAR). He began with a review of the association of aneurysm sac behavior with long-term survival following endovascular aneurysm repair (EVAR). Studies by Deery et al and Li et al found that sac expansion (>5 mm) at 1 year was independently associated with late mortality, regardless of the presence or absence of endoleaks; and one by O’Donnell et al found that an association between sac behavior and long-term mortality persisted in patients without endoleaks and was not modified by reintervention.

Dr. Schermerhorn provided results on 5-year sac behavior from the Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE) study, which prospectively collected global real-world data on the Endurant Stent Graft System (Medtronic) from aortic abdominal aneurysm subjects. The study found that 1-year status of sac increase is predictive of future sac behavior.

He also presented information from the Vascular Implant Surveillance and Interventional Outcomes Network (VISION), a partnership between the Society for Vascular Surgery Vascular Quality Initiative (SVS VQI) and MDEpiNet to improve the quality, safety, effectiveness, and cost of vascular healthcare by collecting and exchanging information. Categorized by diameter change at 1-year imaging, VISION found sac regression (>5 mm) of 49%; stable sac (<5 mm) of 44%; and sac expansion (≥ 5mm) of 6.7%. He also reviewed sac regression at 8-year reintervention, 8-year rupture, and following sub-stratification, as well as polynomial spline methods.

In conclusion, Dr. Schermerhorn reiterated that sac regression at 1 year is strongly associated with important outcomes, such as mortality, re-intervention, rupture, and 5-year sac dynamics. He pointed out that the amount of aneurysm sac regression and expansion at 1 year is important as well. Dr. Schermerhorn suggested that future studies are needed to determine how to improve 1-year sac regression and determine appropriate follow-up intervals for these patients.