Relative rates of blood flow reduction during transcatheter arterial embolization with tris-acryl gelatin microspheres or polyvinyl alcohol: quantitative comparison in a swine model.

PURPOSE

To determine whether two commonly used embolic agents have differing rates of blood flow reduction during transcatheter embolization of the renal arteries in an animal model.

MATERIALS AND METHODS

The renal arteries of 10 pigs were embolized with either polyvinyl alcohol (300-500 or 500-700- micro m) or tris-acryl gelatin microspheres (300-500 or 700-900- micro m). Equivalent unit doses of each agent were suspended in 40 mL of fluid and injected in 1-mL aliquots for 20 mL and then in 5-mL aliquots for 20 mL. Blood flow was measured after each aliquot with an intraarterial Doppler flow wire placed through the embolization catheter.

RESULTS

Renal arterial blood flow was most rapidly and reliably decreased by 300-500- and 700-900- micro m microspheres, both of which had achieved >90% reduction from baseline flow after the injection of 6 mL of suspension. An equivalent reduction in flow required 25 mL of 300-500- micro m PVA suspension and 30 mL of 500-700- micro m PVA suspension. The reduction in blood flow with microspheres was significantly greater (P <.05) than that with PVA between 5 and 19 mL of suspension delivered. Differences between larger and smaller particle sizes of the same agent were not statistically significant.

CONCLUSIONS

Tris-acryl gelatin microspheres reduced renal blood flow more quickly and reliably than did PVA. The type of agent used in embolization had a greater impact on the rate of flow reduction than did particle size in the range of sizes tested.