Incidence and effect of bare suprarenal stent struts crossing renal ostia following EVAR

Objectives. The incidence and effect of bare stent struts crossing the renal ostia following endovascular aortic aneurysm repair with the Talent stent-graft is not known. The study aims to establish the incidence in which bare stent struts cross the renal ostia and to assess any associated effects on renal function. Methods. Fifty-five patients (51 men, mean age 73 years, range 57-90) who had endovascular repair of their abdominal aortic aneurysms with a Talent suprarenal stent-graft were included in the study. Patients were scanned at a variety of follow-up periods (median 24 months, range 3-102). The relationship between the bare stent struts and the renal ostia, together with renal function were retrospectively recorded. The presence and location of the bare stent struts was assessed using CT virtual intravascular endoscopy (CT VIE). Struts were defined as being absent, peripherally located or in the central channel of the renal ostia. Renal function was assessed from glomerular filtration rates (GFR) derived from serum creatinine levels and the Cockcroft and Gault formula. Results. A total of 109 renal ostia were evaluated by CT VIE with one patient having a previous nephrectomy. Bare stent struts crossed 1 renal ostium in 22 (40%) patients and bilateral ostia in 5 (9%) patients. Of the 109 ostia assessed, 15 (14%) ostia were crossed centrally and 17 (16%) had struts crossing the ostium peripherally. There were no statistically significant differences in the change between pre-operative GFR and latest GFR in the group without any strut involvement (6 mLs/min +/- 7 mLs/min) and the group with struts crossing one or both renal ostia (2 mLs/min +/- 9 mLs/min; p > .05). Conclusion. Peripheral or central coverage of renal ostia by bare stent struts occurs in a third of all renal arteries following EVAR. Crossing of renal ostia by bare stent struts does not affect follow-up GFR.