The immediate post-operative impact of infrarenal aortic endografts on renal arterial flow dynamics: Insights from four-dimensional flow magnetic resonance imaging analysis.

ABSTRACT

OBJECTIVES: This study aims to quantify changes in renal blood flow before and after endovascular aneurysm repair (EVAR) using four-dimensional (4D) flow magnetic resonance imaging (MRI) and evaluate its correlation with renal impairment. METHODS: In this retrospective analysis, 18 patients underwent elective EVAR for infrarenal fusiform abdominal aortic aneurysms using Excluder or Endurant endografts. 4D flow MRI scans were conducted before and 1-4 days after EVAR. Hemodynamics were quantified at the suprarenal aorta (SupAo), bilateral renal arteries (RRA and LRA), and infrarenal aorta (InfAo). Cardiac phase-resolved blood flow values (BFVs), relative flow distribution (RFD), and flow change rates (FCRs) were assessed. Estimated glomerular filtration rate (eGFR) was measured pre- and postoperatively. RESULTS: A total of 16 patients were analyzed after excluding two outliers. Pre-EVAR BFVs were 23.1 ± 8.3, 3.7 ± 1.3, 3.4 ± 1.2, and 15.1 ± 5.9 mL/cycle, while post-EVAR BFVs were 20.9 ± 6.9, 3.8 ± 1.1, 3.2 ± 0.9, and 12.1 ± 4.3 mL/cycle in SupAo, RRA, LRA, and InfAo, respectively. Comparing Excluder (N = 8) and Endurant (N = 8), the total renal FCR was 121.8% [106.6-144.7] versus 101.3% [63.8-121.8] (p = 0.110), suggesting a potential improvement in renal blood flow with the Excluder, although not statistically significant. A significant correlation was found between the total renal FCR and the relative eGFR at 6 months (Spearman correlation coefficient, 0.789; p < 0.001). CONCLUSIONS: The endografts, particularly the Excluder, showed potential in improving renal artery blood flow in some patients. The significant correlation between the total renal FCR and the relative eGFR at 6 months suggests that acute hemodynamic alterations induced by EVAR may impact post-operative renal function. Further research is needed to confirm these findings and assess their clinical implications.