Embolotherapy of aneurysms under temporary balloon occlusion of the neck -In vitro study of a newly designed eccentric balloon catheter

RATIONALE AND OBJECTIVES. TO test embolotherapy of aneurysms in an in vitro model using standard and specially designed eccentric occlusion balloon ca theters for simultaneous delivery of the embolization agent and occlusion o f the neck of the aneurysm. METHODS. Two different in vitro set-ups were used: a bifurcational aneurysm and an aneurysm with a straight parent vessel segment, both made from elas tic silicone and glass. Each model was exposed to a pulsating perfusion. Th e effluent was collected and filtered. For the bifurcational aneurysms, com mercially available occlusion balloon catheters with a working channel exit ing at the tip were used. For the aneurysms with straight parent vessel, th e catheters were modified so that the balloon opened eccentrically. The wor king channel of the catheter led to a side hole, which was located where th e balloon membrane was fixed to the catheter shaft. The aneurysms were fill ed with coils, ethibloc, or hydrogel, and with coils combined with ethibloc or hydrogel, while the expanded balloon Occluded the neck. RESULTS. Embolization of aneurysms under balloon occlusion of the neck was technically feasible with the catheter devices. Dense packing with coils wa s possible in all cases without coil dislocation, but unfilled interspaces remained between the coil wires. Best filling was achieved with ethibloc or hydrogel alone or in combination with coils. During the filling procedure, there was no distal embolization of the liquid agents. However, after ball oon deflation, considerable amounts of hydrogel or ethibloc were washed out from the aneurysm. CONCLUSIONS. The results suggest that balloon occlusion of the neck allows compact filling and minimizes the risk of dislocation in coil embolotherapy of aneurysms. In nonbifurcational aneurysms, the eccentric balloon cathete r seems to be suitable for this treatment concept. Although liquid agents m ay be safely delivered into the aneurysm under balloon protection, their co nsiderable washout rate after balloon removal requires further refinements of the technique before clinical application is advisable.