Revascularization of occluded renal artery stent-grafts following complex endovascular aortic repair and its impact on renal function.

Abstract Background Acute occlusion of the renal bridging stent-grafts after fenestrated/branched endovascular aortic repair (F/B-EVAR) is an acknowledged complication with high morbidity often resulting to chronic dialysis dependence. The feasibility and effect of timely or late (≥6 hours of ischemia) renal artery revascularization has not been adequately reported in the literature. Methods We performed a retrospective, multi-centre study across 11 tertiary institutions of all consecutive patients that underwent revascularization of renal artery stent-graft occlusions after complex EVAR. Endpoints were technical success, association between ischemia time and renal function salvage, interventional complications, mortality, and mid-term outcomes. Results Between 2009 and 2019, 38 patients with 46 target vessels (TVs; 8 bilateral occlusions) were treated for renal artery occlusions after complex EVAR (mean age 63.5±10 years, 63.2% male). Six patients had a solitary kidney (15.8%). 42.1% (16/38) of the patients were treated with FEVAR and 57.9% (22/38) with BEVAR. Technical success was 95.7% (44/46 TVs). The recanalization technique used was sole aspiration thrombectomy (5.3%), aspiration thrombectomy and stent-graft relining (52.6%) and sole stent-graft relining (36.8%). Median time of renal ischemia was 27.5 hours (Range 4-720 hours, IQR 4-36 hours); 94.4% of the patients were treated after at least 6 hours of renal ischemia time and 55.6% after 24 hours. In 14 patients (36.8%) renal function improved after the intervention (mean GFR improvement 14.2±9), and in 24 patients (63.2%) showed no improvement. Improvement of renal function did not correlate with the time of renal ischemia. Of the 14 patients with bilateral renal artery occlusion or solitary kidney, 9 had partial recovery of renal function requiring no hemodialysis. In-hospital mortality was 2.6%. The cause of the renal stent-graft occlusion could not be identified in 50% of the TVs (23/46), and in 41.3% (19/46) a significant stenosis or kink of the renal stent-graft was determined. Median follow-up was 11 months (IQR 0-28 months). The estimated 1-year patient survival and patency rate of the renal stent-grafts was 97.4% and 83.8% respectively. Conclusion Revascularization of occluded renal bridging stent-grafts after F/B-EVAR is a safe and feasible technique, which can lead to significant improvement of renal function, even after long ischemia times (> 24 hours) of the renal parenchyma or bilateral occlusion, as long as there is preserved residual perfusion of the renal parenchyma. Also, the long-term patency rates justify aggressive management of renal artery occlusion after F/B-EVAR.