Impact of a Substantial Oversizing Strategy in Chimney Endovascular Aneurysm Repair on Aortic Neck Behavior and Clinical Outcomes Compared with Open Repair for Challenging Aortic Necks.

BACKGROUND

This study aimed to compare early and long-term outcomes of chimney endovascular aneurysm repair (chEVAR) using a polyester endograft with a substantial oversizing strategy versus open repair (OR) for abdominal aortic aneurysms (AAAs) with challenging proximal necks, and to elucidate key determinants of successful chEVAR.

METHODS

We retrospectively analyzed patients undergoing chEVAR (n = 112) or OR (n = 51) for AAAs with short-neck infrarenal, juxtarenal, or pararenal anatomy between May 2005 and October 2023. Primary endpoints were 30-day/in-hospital mortality and major adverse events (MAEs). Secondary endpoints included freedom from aneurysm-related adverse events and mortality, reintervention, and long-term survival. ChEVAR-specific analyses assessed freedom from type Ia endoleak (T1aEL), predictors of T1aEL, aneurysm sac behavior, and longitudinal proximal neck dilatation.

RESULTS

In-hospital mortality tended to be lower with chEVAR (1.8% vs. 7.8%, P = 0.057), and 30-day MAEs were significantly reduced (10.7% vs. 37.3%, P < 0.001). Five-year freedom from aneurysm-related adverse events was higher for chEVAR (64.9% vs. 60.5%, P = 0.015). Freedom from aneurysm-related mortality, reintervention, and overall survival were similar. Three-year freedom from T1aEL was 97.5%. Predictors of T1aEL included bare metal chimney stents, multiple chimneys, larger neck diameter, shorter neck length, and reverse taper neck. Mean annual neck dilatation rate was 0.13 at the infrarenal level. Patients with or without significant neck dilatation (≥0.20; fourth quartile) had similar T1aEL rates.

CONCLUSION

ChEVAR demonstrated favorable early outcomes and comparable long-term results compared to OR. Chimney EVAR can be performed successfully without increasing the incidence of T1aEL, even in the presence of significant neck dilatation, provided that appropriate anatomical selection is applied.