Implications of renal artery anatomy for endovascular repair using fenestrated, branched, or parallel stent graft techniques

Objective This study evaluated renal artery (RA) and accessory renal artery (ARA) anatomy and implications for endovascular repair using fenestrated, branched, or parallel (chimney, snorkel, and periscope) stent graft techniques. Methods We analyzed the digital computed tomography angiograms of 520 consecutive patients treated by open or fenestrated endovascular repair for complex abdominal aortic aneurysms (2000-2012). RA/ARA anatomy was assessed using diameter, length, angles, and kidney perfusion based on analysis of estimated volumetric kidney parenchyma. Endovascular suitability was determined by RA diameter ≥4 mm, length to RA bifurcation ≥13 mm, and preservation of >75% of a single kidney or >60% of two kidneys by volumetric kidney parenchyma analysis. Results There were 222 juxtarenal (43%), 241 suprarenal (46%), and 57 type IV thoracoabdominal aortic aneurysms (11%), Analysis of 1009 RAs and 177 ARAs showed endovascular incorporation was possible in 884 RAs (88%) and 30 ARAs (17%) using the proposed criteria. One or more factors rendered RA incorporation unsuitable in 97 patients (19%), including early bifurcation in 45 (9%), small diameter in 28 (5%), or inability to preserve kidney parenchyma in 28 (5%). Other anatomic issues were present in 170 patients (33%) that would increase technical difficulty to RA incorporation using transfemoral access, including excessive downward angulation in 125 (24%), high-grade stenosis in 51 (10%), or prior renal stents in 11 (2%). Conclusions Independent of the endovascular technique that is selected to treat a complex abdominal aortic aneurysm, one of five patients has anatomic limitations to endovascular incorporation. In these patients, open repair may provide the best alterative to maximize RA patency and preserve renal function.