New morphological factor for predicting late proximal type I endoleak after endovascular aneurysm repair.

ABSTRACT Background : Although we have witnessed several cases of late proximal type I endoleak (T1AEL) after endovascular aneurysm repair (EVAR), most patients did not have “hostile neck” preoperatively. We hypothesized that the distance between the lowest renal artery and the neck angulation point and neck length are the two most important factors for maintaining long-term proximal sealing. This study evaluated “neck hostility”, which is the product of the distance to the angulation point and the neck length, as a preoperative morphological risk factor for the development of late T1AEL after EVAR. Methods : A retrospective review of a prospectively assembled database was performed for all patients who had undergone EVAR at a single institution from June 2007 to May 2017. Patient demographics and preoperative imaging data were collected, and Cox regression analysis was performed to identify the risk factors for late T1AEL. Results : Of the 655 patients who underwent EVAR during the study period, 115 were excluded due to complex EVAR (n=14), primary indications for iliac aneurysms (n=86), primary T1AEL (n = 3), or other reasons (n=15). Of the remaining 537 patients, twelve patients (2.2%) developed late T1AEL a median of 3.2 (interquartile range [IQR]; 3.0, 5.4) years after EVAR. Receiver operating characteristic (ROC) curve analysis revealed a neck hostility cutoff value of 8. Cox regression analysis revealed that a neck hostility value ≤8 and conical neck anatomy were risk factors for the development of late T1AEL after EVAR. Well-known hostile neck factors such as short neck, severe angulated neck, and severe calcification/thrombus in the proximal neck were not significantly different. Conclusions : The present study demonstrated a correlation between late T1AEL and the product of the angulation distance and the neck length. This factor may be useful for predicting poor late proximal outcomes after EVAR.