Is Suprarenal Fixation of Aortic Stent Grafts Really without Consequence on the Renal Function?

Background: The renal safety of suprarenal (SR) fixation stent grafts has not been demonstrated yet. The principal objective of this study was to analyze the effect of the type of fixation of stent grafts on the renal function at 1 year, by calculating the estimated glomerular filtration rate (eGFR). The secondary objective was the evaluation of the morphological repercussion of the implants at the renal level by computed tomography.

Methods: This is a monocentric retrospective study, including all the patients treated electively between 2008 and 2014 with a bifurcated aortic stent graft. We compared the characteristics of the SR and infrarenal (IR) populations and the evolution of the preoperative and 1-year postoperative renal function. Renal function was evaluated by eGFR, according to the Chronic Kidney Disease Epidemiology Collaboration formula, and expressed as mL/min/1.73 m. Regarding morphological evolution, we sought renal infarctions and thromboses or stenoses of the renal arteries (RAS).

Results: During the study period, 102 patients were treated: 42 IR and 60 SR. The populations were comparable in terms of operative risk factors and impaired renal function. Preoperative eGFR was similar (SR 71.7 ± 17.8 vs. IR 70.3 ± 17.5, P = 0.7). There was no variation in eGFR at 1 year in the IR group (-0.9; P = 0.4), whereas a significant decrease was observed in the SR group (-5.6, P < 0.0001), a difference which proved to be significant in the intergroup comparison (P = 0.0065). This difference persisted after the exclusion of the patients in which at least one polar renal artery had been covered (P = 0.019). The proportion of patients with a degradation ≥20% of the eGFR was significantly higher in the SR group (SR 13.3%, n = 8 vs. IR 2.4%, n = 1; P = 0.046). We observed significantly more new or progressing RAS in the SR group (SR 21.67%, n = 13 vs. IR 2.38%, n = 1; P = 0.0035). Overall, 15 infarctions were detected but 9 were due to the cover of a polar artery including 8 in the SR group SR, which were thus excluded (SR 6.7%, n = 4 vs. IR 4.8%, n = 2; P = 0.52). No renal artery thrombosis was diagnosed.

Conclusions: The report of a significant difference in the evolution of the renal function and the progression of renal stenoses makes us wonder about the real harmlessness of SR fixation stent grafts. If further reflection is necessary, their systematic use should be called into question, in particular in the presence of an anatomy authorizing the use of IR fixation stent grafts.