Renal outcomes of suprarenal vs. infrarenal endograft fixation in endovascular abdominal aortic aneurysm repair: a narrative review

Abstract

Background and Objective: Abdominal aortic aneurysm (AAA) is a common pathology with a prevalence of 4.8%. AAA rupture is associated with significant mortality and so early diagnosis followed by regular monitoring is needed until treatment might be considered and plan intervention. Endovascular aneurysm repair (EVAR) is an established and effective alternative to open surgical repair (OSR) in the treatment of AAAs. Key parameters in defining conventional EVAR suitability include the infrarenal neck length and angulation for the fixation of the proximal graft component. Endograft fixation can be either suprarenal or infrarenal and much debate exists as to which approach is associated with optimum renal outcomes. This study aims to review the current literature with respect to the renal outcomes associated with conventional EVAR using suprarenal fixation (SRF) vs. infrarenal fixation (IRF). Methods: A search was conducted from major search indices (PubMed, Google Scholar and EMBASE) to identify relevant literature pertaining to renal outcomes in EVAR. Recent papers comparing SRF and IRF were evaluated and their findings discussed. Key Content and Findings: The mechanism of renal function decline (RFD) following EVAR is uncertain and likely multifactorial. Aortic morphology, endograft type and surgical technique may all contribute to RFD. There is a significant degree of heterogeneity within the literature regarding study design and definitions of RFD. Recent literature suggests that RFD is more acute for SRF than IRF in the first post-operative year, but the clinical significance of this decline in patients with normal kidney function is questionable. Studies indicate that SRF is associated with accelerated RFD at 5 years, and that the RFD is worse in patients who are female and who have pre-existing renal insufficiency. Conclusions: SRF is associated with a greater decline in renal function than IRF in both short- and long-terms. Although clinically insignificant in the short-term, the limited available long-term evidence suggests that SRF results in a relatively accelerated decline in renal function when compared to IRF, but it is possibly partially explained by the higher prevalence of advanced degenerative/atherosclerotic disease in SRF cohorts. These trends are noted particularly in female patients and in patients with baseline renal insufficiency.