An experimental study of embolic effect according to infusion rate and concentration of suspension in transarterial particulate embolization

RATIONALE AND OBJECTIVES. The authors evaluate the embolic effect according to infusion rate and concentration of particulate suspension, focusing on arterial occlusion level. METHODS. The renal arteries of 14 rabbits were embolized with 150 to 250 mu m polyvinyl alcohol (PVA) particles, divided into four groups according to two different infusion rates (1 mg/second and 0.1 md/second) and two different concentrations of suspension (10 mg/mL and 2.5 mg/mL). Arteriograms obtained immediately and a week after embolization were assessed for occlusion level. For the nephrograms obtained a week after embolization, the opacifying areas were graded from 0 to 4. Median coronal sections of each kidney specimen were investigated for the presence of peripheral infarct grossly and for the presence of PVA particles in the small artery microscopically. RESULTS. Arteriograms showed various occlusion levels. Using a 0 to 4 grading system, the opacifying area of the nephrogram obtained 1 week after embolization was noted to be smaller in the low infusion rate group (P < 0.05). In gross and microscopic pathologic examination, the number of cases with peripheral infarct or PVA particles in the small artery (<300 mu m) was greater in the group with the low infusion rate and low concentration (P < 0.05). CONCLUSIONS. In transarterial particulate embolization, slower infusion of more diluted suspension provides for a more distal arterial occlusion.