Effect of renal artery stenosis on feasibility and renal outcomes after FEVAR
Panos Kougias, Neal Barshes, Sherene Sharath, Nader Zamani
Baylor College of Medicine, Houston, TX
Background: Ostial renal artery stenosis can increase the technical complexity of fenestrated endovascular aneurysm repair (FEVAR) procedures. It can also affect renal stent patency and subsequently long-term renal function. We sought to determine the effect of renal artery stenosis on technical success, renal stent patency and renal function in patients with juxtarenal or suprarenal abdominal aortic aneurysms (AAA) undergoing elective FEVAR. Methods: We conducted a single institution retrospective analysis of consecutive procedures performed from 2013 to 2019 in patients with preserved renal function (estimated Glomerular Filtration Rate – eGFR of 30 or greater) who underwent elective FEVAR for juxtarenal or suprarenal AAA. The procedures were performed using either the ZFEN or P-Branch devices. Renal artery stenosis (RAS) was defined as 60% or greater luminal stenosis as measured in preoperative CT angiography. Postoperative renal decline was defined a reduction in eGFR of 50% or greater compared to baseline. Cox proportional hazards regression was used to model predictors of renal function decline. Results: The analysis included 168 patients with at least one year follow up renal function data. The median age was 65 (range: 58 to 82). Most of the procedures (93%) included fenestrations in both renal arteries, whereas 25% of cases included fenestrations in both renal arteries and the superior mesenteric artery. There were 32 (19%) of patients in the RAS group. Renal artery pre-dilation was performed prior to FEVAR using a staged approach in 12 patients with severe (90% or greater) RAS. There was no difference in age or comorbidities between the RAS and non-RAS groups. The FEVAR procedures were performed with 100% technical success (all target vessels cannulated and stent successfully deployed). With respect to the renal artery stents the primary patency at one year was 93 vs. 92%; and at three years 89 vs 90% for the RAS and non-RAS groups respectively (p = NS). The primary assisted patency at one year was 95 vs. 97%; and at three years 89 vs. 94% in the RAS and non-RAS groups respectively (p = NS). Freedom from renal function decline at one year was present in 89 vs 84%, and at three years in 75 vs. 81% of patients in the RAS and non-RAS groups respectively (p = NS). In multivariable time to event analysis only age (HR: 2.21, 95% CI: 1.12 to 4.23) and diabetes (HR: 1.57, 95% CI: 1.0 to 2.34) were independent predictors of renal function decline. Similarly, no association between renal artery stenosis and renal function decline was seen when the degree of renal artery was modeled as a continuous, numerical variable. Conclusions: FEVAR can be successfully performed in the presence of renal artery stenosis. Selective renal artery pre-dilation with balloon angioplasty in a two-staged approach may be used to technically facilitate the FEVAR procedure. We found no association between renal artery stenosis and either stent patency or postprocedural renal function decline, the latter likely due to the fact that long-term renal function is dependent upon intraparenchymal physiologic rather than vascular anatomic determinants.
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