Impact of Proximal Neck Anatomy on Short-Term and Mid-Term Outcomes After Treatment of Abdominal Aortic Aneurysms With New-Generation Low-Profile Endografts. Results From the Multicentric “ITAlian North-East Registry of ENDOvascular Aortic Repair With the BOltOn Treo Endograft (ITA-ENDOBOOT)”

Background: The aim of the study was to evaluate the short-term and mid-term technical and clinical outcomes of the Bolton Treo endograft in subjects with abdominal aortic aneurysm (AAA) requiring endovascular aortic repair (EVAR) and assess if presence of hostile proximal neck would represent a risk factor for increased failure rates. Methods: A retrospective review of all consecutive patients who had undergone elective or non-elective EVAR with the Bolton Treo endograft at 5 institutions located in the North-East of Italy (January 2016–December 2020) was performed. The main exposure variable for this study was presence of hostile (HAN) or friendly (FAN) aortic neck. Results: A total of 137 consecutive patients were treated with the Bolton Treo endograft at participating institutions; of these 63 (46%) presented HAN while 74 (54%) had FAN. At baseline, no significant differences were observed in the distribution of demographics and comorbidities between study groups. Two type Ia endoleaks (EL) were detected at completion angiography, all in patients with HAN but none in patients with FAN (3% vs. 0%, P = 0.04), but no type III EL were identified in the whole cohort. The median duration of follow-up in the study cohort was 30 months (IQR 22–34 months) and was similar between study groups (P = 0.87). At 3-years, survival estimates were 89% and 91% (P= 0.82) in patients with HAN and FAN, respectively. At three years, patients with HAN had significantly lower freedom from type IA endoleak as compared with patients with FAN (87% vs. 94%, P= 0.02). No significant differences were found between study groups in the three-year estimates of freedom from reinterventions (80% vs. 86%, P= 0.28). Using cox proportional hazards, presence of type II EL (HR 3.15, 95%CI 1.18–8.5, P= 0.02) and presence of type IA EL (HR 4.22, 95%CI 1.39–12.85, P= 0.01) were found as independent predictors for reinterventions in univariate analysis, although they were no longer significant in the multivariate model. Freedom from sac increase >5mm at three years were not significantly different between study groups (92% vs 91%, P= 0.95). Conclusions: Within a contemporary multicentric real-world experience, EVAR with the Bolton Treo endograft shows a satisfactory safety profile in the immediate postoperative phase and acceptable outcomes during mid-term follow-up. Presence of HAN is correlated with development of type Ia EL (either early following stent-graft implantation or late after EVAR) which, in turn, may represent a significant factor leading to reinterventions.