Increased Mortality after Endovascular Aortic Aneurysm Repair in Patients with Enlarged Aortic Necks

Achieving a durable proximal seal in the aortic neck during an endovascular aortic aneurysm repair (EVAR) is critically important for a long-lasting repair. While current stent grafts are designed to accommodate neck diameters up to 32mm, there is concern that EVAR in ectatic aortic necks could have higher rates of proximal seal failures. This study evaluates the contemporary outcomes after EVAR for patients with wide but otherwise non- hostile aortic necks using the Vascular Quality Initiative (VQI) and seeks to determine if certain proximal seal strategies are associated with improved outcomes. Procedural and long-term follow-up data from the international EVAR VQI dataset (updated March 2023) were analyzed. Patients with prior aortic surgery, investigational device exemption use, short (<15 mm) or highly angulated (>60 degrees) aortic necks, aortic neck diameters (ND) <19 mm or ≥32 mm, and repairs using non-bifurcated stent grafts were excluded from the study. Survival was assessed with Kaplan-Meier analysis, case-mix controlled with propensity-matching, and variables associated with mortality were estimated using Cox proportional hazard regression analysis. A total of 16,497 EVARs were included in our study population, of which 11,838 (72%) were performed for normal (N) aortic necks (19 ≤ ND <26 mm), 3128 (19%) for wide (W) necks (26 ≤ ND <29 mm), and 1531 (9%) for very wide (VW) necks (29 ≤ ND <32 mm). Overall survival after EVAR was statistically-significantly lower with W and VW necks, with 5-year survival of 86.1%, 84.8%, and 83.4%, for N, W, and VW necks respectively (Fig 1). Compared with patients with normal aortic necks, aneurysm sizes were larger, and use of suprarenal fixation and endoanchors were more prevalent in patients with W and VW necks. On completion angiogram, there was a higher rate of type 1a, but lower rate of type 2, endoleaks in VW necks. Sac dynamics, long-term type 1a endoleaks, and reintervention rates were not significantly different between groups, although with a mean follow-up time of just over a year. Patients with VW necks, compared with propensity-matched N + W necks, had increased risk of overall mortality (hazard ratio, 1.37; P < .01). In patients with VW necks, neither suprarenal fixation nor use of endoanchors significantly impacted mortality (Table 1). EVAR in patients with enlarged but otherwise non-hostile aortic necks is associated with slightly worse long-term overall survival. Suprarenal fixation and endoanchors were not associated with improved survival in this population, though whether they impact long-term aneurysm-specific outcomes require further investigation.TablePredictors of mortality after endovascular aneurysm repair (EVAR) for patients with very wide necks (29 mm ≤ neck diameter [ND] <32 mm) after EVAR using multivariate Cox regressionCovariatesHazard ratio (95% CI)PAge, per year1.04 (1.02-1.06)<.001Female sex1.53 (0.97-2.43).068Maximum AAA diameter, per mm1.03 (1.02-1.04)<.001BMI <18.5 kg/m21.52 (0.64-3.60).342Preoperative aspirin0.77 (0.54-1.08).134Preoperative anticoagulation1.29 (0.85-1.94).229Coronary artery disease1.62 (1.15-2.28).005Unfit for open operation1.55 (1.08-2.23).017Suprarenal stent graft0.88 (0.59-1.30).515Endoanchors1.64 (0.94-2.85).082AAA, Abdominal aortic aneurysm; BMI, body mass index; CI, confidence interval.Boldface P values indicate statistical significance. Open table in a new tab