Incidence of Renal Infarctions after Transrenal Stent Placement in an Animal Model

Purpose: To evaluate the incidence and appearance of renal infarctions after transrenal stent placement in an animal model. Methods: An aortic stent was placed via a femoral approach in 20 female Merino sheep. Ten animals had intentional coverage of one renal ostium with the bare struts, 1 sheep had both renal artery ostia covered, and the other 9 sheep had no stent impingement on the renal orifices. Animals were sacrificed after 3 to 12 months (mean 6) for gross pathological and histological evaluation. Infarction locations and patterns were evaluated and correlated to stent placement. Results: Of the 40 renal arteries, coverage was proven at autopsy in 12 cases; the remaining 28 arteries were free of any stent overlay. Overall, 14 (35%) renal infarctions were detected; 7 were found in the 12 arteries with a transrenal stent (58.3% incidence in covered renal arteries). By comparison, the other 7 infarctions were found in the 28 unaffected arteries (25% incidence in noncovered renal arteries; p=0.04). All infarctions appeared to be well-defined punctate lesions. Conclusions: A transrenal stent position in the abdominal aorta is related to increased renal infarctions in an animal model.