IN-VITRO STUDY OF HEMODYNAMICS IN A GIANT SACCULAR ANEURYSM MODEL - INFLUENCE OF NOW DYNAMICS IN THE PARENT VESSEL AND EFFECTS OF COIL EMBOLIZATION

The purpose of this study was to investigate the influence of flow dyn amics in the parent vessel and of intra-aneurysmal coil embolisation o n flow pattern and pressure in an in vitro model of giant aneurysm. A pulsatile perfusion with a glycerol aqueous solution was installed in a silicone model of a lateral giant aneurysm. Flow visualisation and p ressure measurements were performed while modifying the flow rate, the pulsatility and the pulse rate in the parent vessel, and after partia l coil embolisation. Vortices were formed during systole at the downst ream lip of the aneurysm and circulated around the aneurysm. The centr e and dome of the aneurysm were areas of fluid stagnation. Flow rate a nd pulsatility were the main factors which varied the pattern of flow within the aneurysm. Partial coil embolisation induced major flow dist urbances in the aneurysm, in particular fluid stagnation at the dome. Pressure measurements were similar in the aneurysm and in the parent v essel. It was concluded that the pulsatility of flow is as important a s the flow rate when considering the haemodynamics in a giant aneurysm . In the clinical context, this could explain the efficacy of vertebra l artery occlusion in thrombosing giant vertebrobasilar aneurysms. Stu dies with intra-aneurysmal coil embolisation showed early fluid stagna tion at the dome. This could result in embolic migration during endova scular treatment. Partial coil embolisation may prevent early rebleedi ng; however, it may induce additional mural stresses resulting from ne w haemodynamic forces and compliance mismatch.