Effect of suprarenal stent struts on the renal artery with ostial calcification observed on CT virtual intravascular endoscopy.

OBJECTIVES: The behaviour of stent struts crossing the renal ostia and their effect on renal ostia configuration is not well understood. The study aims to investigate whether suprarenal stent struts affect the morphological change of the renal artery with ostial calcification observed on CT virtual intravascular endoscopy. METHODS: Nine patients with abdominal aortic aneurysms undergoing suprarenal fixation of stent grafts were included in the study. All patients received a Zenith endovascular graft with uncovered suprarenal components placed above the renal arteries. Renal ostial calcification and configuration of stent wires crossing the renal ostium were characterized in each patient and maximal transverse and longitudinal diameters of the renal ostia were measured on virtual endoscopy pre- and post-stent grafting. RESULTS: There were altogether 17 renal ostia assessed with one patient having atrophic left kidney and no renal ostium being observed. Ostial calcification was found in five of the left renal ostia and five of the right renal ostia with one patient having bilateral ostial calcification. There was no significant difference between the renal ostial diameters measured pre- and post-stent grafting (p>0.05). Suprarenal stent struts were found to cross the renal ostia in various configurations observed on virtual endoscopy. All of the renal arteries were patent on follow-up CT scans after suprarenal fixation without stenosis or occlusion being observed. One patient with atrophic left renal artery developed renal failure following suprarenal stent grafting and received renal dialysis, while in the remaining cases median serum creatinine level did not change significantly. CONCLUSIONS: Suprarenal stent struts did not significantly affect the renal ostia with ostial calcification in terms of the diameter measurements and renal function. Further studies deserve to investigate the long-term effect of stent struts on the renal artery in terms of cross-sectional area reduction caused by stent wires and ostial calcification.