Development of damage to porcine renal arterial vascular anatomy and blood flow after cryoablation: acute to 2 weeks

Abstract

Aimto better understand the acute and successive events of renal cryoablation.MethodsIn 20 anesthetized pigs renal cryoablation was applied for 20 minutes. Kidneys were divided into five groups with pig survival time after ablation of 20 min, 4 hrs, 2, 7 and 14 days after ablation. Before euthanasia, fluorescently labeled microspheres were intravenously administrated. The kidney was harvested, the main renal artery flushed, filled with a fluorescence dyed elastomere, frozen and processed in an imaging cryomicrotome. 2 stacks of 4000 images of 2000×2000 pixels where obtained. The 1st stack resulted in a 3D image of the arterial structure the 2nd stack in the 3D microsphere distribution matched to arterial structure.ResultsIn the 20 min group, vascular structures with diam >200 μm remained in the ablated area but microspheres passing through were only found in surrounding tissue. No spheres were found within the ablated area. Ablated zone vascular structures disappeared completely after 1 week. In this and later groups, all microspheres in the surrounding tissue arrived by the non‐affected vessels.ConclusionAcute injury induced by cryoablation regards vessels smaller than 200 μm leaving the structure of larger vessels intact allowing blood flow to the surrounding tissue. It takes 1 week for complete destruction of vessels in the ablated area and bock blood flow.