Ethiodized oil-ethanol capillary embolization in rabbit kidneys: temporal histopathologic findings

To determine the temporal histopathologic findings associated with selective arterial injection of a 1:1 ethiodized oil-ethanol mixture (EEM) in normal rabbit kidney followed by administration of pure ethanol into the main renal artery.

In five rabbits, the EEM was injected sequentially into each segmental renal artery of the right kidney until capillary stasis occurred. Pure ethanol was then injected into the main renal artery to achieve complete arterial stasis. Before sacrifice, the left kidney in each animal was acutely (ie, with a short follow-up period) embolized by using the same technique. The 10 kidneys of the five rabbits were evaluated microscopically at 1 (n = 3), 1(1/2) (n = 1), and 3 hours (n = 1) and 1 (n = 1), 3 (n = 1), 5 (n = 1), 7 (n = 1), and 14 days (n = 1) after embolization.

Injection of the EEM (mean volume, 0.46 mL +/- 0.14 [SD]) followed by ethanol alone (mean volume, 0.25 mL +/- 0.09) led to complete stasis in all kidneys. There was no recanalization in the chronically (ie, with a longer follow-up period) embolized kidneys. Microscopically, uniform distribution of the EEM was evident in all slices at all time points. From 1 to 3 hours, sloughing of endothelium, formation of thrombi, and deposition of eosinophilic material along the renal, interlobar, and arcuate arteries were observed, without evidence of parenchymal damage. Within 24 hours, complete coagulative necrosis of the entire kidney occurred as a result of an occluding thrombus in the main renal artery. Analysis at subsequent time points revealed liquefaction of necrotic tissue and replacement with granulation tissue.

In the rabbit, selective renal arterial injection of EEM followed by administration of ethanol produces vascular endothelial damage initiating thrombosis that results in renal infarction and ablation within 24 hours.