ARE SUPERABSORBERS USEFUL FOR ENDOVASCULAR EMBOLIZATION OF SACCULAR ANEURYSMS - AN IN-VITRO STUDY

RATIONALE AND OBJECTIVES. The authors conducted in vitro evaluation of superabsorber for endovascular embolization of saccular aneurysms. ME THODS. The swelling properties of the superabsorber Sanwet IM-7000 wer e investigated in various solvents. The material used was granulate (g roup A: particle size approximate to 459 mu m; group B: particle size approximate to 20 mu m) as well as cubes with an edge length of 1 mm p repared from a block. With ascending concentrations of Sanwet IM-7000 held in suspensions made of Lipiodol and 96% ethanol, the injectabilit y was determined using microcatheters (2.1 F/3 F). The behavior of San wet IM-7000 as occlusion material for aneurysms was examined in a sacc iform glass-model aneurysm. RESULTS. The granule showed no significant increase in size in Lipiodol and in 96% ethanol, so that they were ch osen for catheter measurement. In Lipiodol suspension the maximum frac tion of the granulate suitable for injection through a 3 F catheter wa s 3.2%. In 96% ethanol suspension the maximum fraction of granulate su itable for injection through a 3 F catheter was 0.8%. Suspended in Lip iodol Sanwet IM-7000 showed a moderate swelling in the aneurysm model, whereas the use of 96% ethanol resulted in a pronounced swelling of t he granulate (100 vol%) after the 96% ethanol was washed off. Irrespec tive of the granulate size used, a rinse-off process of the granulate occurred in the model aneurysm at a flow rate above 200 mL X min(-1). Cubes prepared from a block of the base polymerisate of Sanwet IM-7000 showed a delayed increase in size. The final size in 0.9% NaCl soluti on was reached in the cubes after 220 min, in the granulate already af ter 20 mins. The cubes displayed a high form stability. CONCLUSIONS. D ue to the substance-related absence of intercorporeal cross-linking an d the unpredictable increase in size, embolization of aneurysms using Sanwet IM-7000 granulate is inadvisable at present. In spite of a long er swelling time and because of its form consistency, the use of prepa red cubes could provide a reasonable alternative.