Evaluating the treatment efficiency in endovascular aneurysmal repair (EVAR), does IFU criteria, iliac fixation lenght and certain anatomic differences affect the endoleak rates, aneurymal sac enlargement and reintervention rates

Objective: Evaluating the differences in endoleak rates, aneurysmal sac \ iliac expansion rates, reintervention rates and number of endograft modules used in EVAR patients with different anatomical features, including IFU criteria, iliac fixation and aneurysmal sac diameter. Methods: Fifty patients which are treated with Medtronics Endurant endovascular stent graft in years 2009-2015 in Dokuz Eylul University Interventional Radiology department were included in our study. The patients were grouped according to their IFU criteria compliance, each IFU criteria on a separate evaluation and several other anatomical features including: 1-Iliac fixation lenght, 2-Aneurymal sac diameter exceeding 7cm treshold 3-İliac diameter exceeding 20mm 4-existence of proximal aortic mural thrombus/calcification. The treatment efficiency of different groups are evaluated using criterias: 1-Type 1-3 endoleaks in follow-up 2-Aneurysmal sac and iliac expansion rates 3-Reintervention rates 4-The number of stent graft modules needed in primary operation. The statistical differences among groups were evaluated. Findings: Forty eight percent of patients (24 patients) in follow up group were compliant with IFU criteria and 52% of patients (26 patients) had outside IFU anatomy. The patients who does not match IFU criteria, statistically higher number of endograft modules were used (2,38 versus 2,52 p=0,023). The rates of type 1-3 endoleaks, aortic sac expansion end reintervention rates were same amoung IFU compliant and outside IFU groups (P values 0,351; 0,669 and 1 respectively). In patient groups with hostile neck anatomy, short proximal aortic fixation lenght (>10mm) and outside-IFU iliac anatomy (>25mm), the rates of type 1-3 endoleaks, reintervention rates and aneurysmal sac expansion rates were not statistically different. In patients with inadequate iliac fixation (<15mm), type 1-3 endoleak rates and reintervention rates were statistically higher (p values 0,002 and 0,008 respectively). In patients with aneurysmal sac maximum diameter exceeding 7cm, reintervention rates were statisticaly higher (p=0,035) Conclusion: The treatment efficiency were similar among IFU compliant and non-compliant groups. The endograft modules needed in primary operation was higher in non IFU compliant group. This might be considered a factor in operational cost. In anatomical evaluations including IFU and several other factors, distal fixation lenght was the strongest indicator of type 1-3 endoleaks and reintervention rates. The proximal fixation features was for long considered as the most important factor on a succesful EVAR intervention, but the new changes on graft design might have changed this. The small number of studies on iliac fixation had similar outcomes with our study. Our study supports that distal fixation properties represent a very important and possibly strongest factor on the fate of an endograft.