Long-Term Angiographic and Histological Results of a New Hydrogel-Containing Filling Coil in Experimental Rabbit Aneurysms

Abstract

Background: The aim of this study was to compare the performance of a new filling coil, the HydroFill device, to historical results of HydroSoft and bare platinum coil devices in experimental rabbit aneurysms.

Methods: Experimental aneurysms were constructed in rabbits and embolized with HydroFill (n=32), HydroSoft (n=48), or bare platinum coil (n=47) devices. Angiographic occlusion was evaluated post-treatment and at 1 month (n=55), 3 month (n=20), 6 month (n=35), and 12 month (n=12) follow-ups according to the Raymond scale. The aneurysms were analyzed histologically for neointima formation, thrombus organization, and inflammation. Continuous and discrete results were compared using ANOVA/t-test and χ² tests, respectively.

Results: Volumetric occlusion of the aneurysm sac was increased in the HydroFill group compared to the HydroSoft and platinum coil groups. Protrusions into the parent artery were common in all treatment groups due to the treatment of wide-necked aneurysms without the use of balloons or stents. Although angiographic occlusion post-treatment scores were reduced in the HydroFill group compared to the HydroSoft and platinum coil groups, stable/progressive occlusion was increased in the HydroFill group compared to the platinum coil group. Histologically, neointima formation and thrombus organization scores were increased in the HydroFill and HydroSoft groups compared to the platinum coil group at 3 months. Although there were some differences in the scoring, inflammation was generally minimal to mild in all three groups.

Conclusion: The HydroFill device, with its high levels of volumetric filling, increased stable/progressive occlusion at follow-up, increased neointima formation, and increased thrombus organization, shows promise for clinical use.

Key words

therapeutic embolization - aneurysm - hydrogel - animal models

References

• 1 Molyneux AJ, Kerr RS, Yu LM. et al . International subarachnoid aneurysm trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised comparison of effects on survival, dependency, seizures, rebleeding, subgroups, and aneurysm occlusion.  Lancet. 2005;  366 809-817
• 2 Peluso JP, van Rooij WJ, Sluzewski M. et al . Coiling of basilar tip aneurysms: results in 154 consecutive patients with emphasis on recurrent haemorrhage and re-treatment during mid- and long-term follow-up.  J Neurol Neurosurg Psychiatry. 2008;  79 706-711
• 3 Sluzewski M, Menovsky T, van Rooij WJ. et al . Coiling of very large or giant cerebral aneurysms: long-term clinical and serial angiographic results.  AJNR Am J Neuroradiol. 2003;  24 257-262
• 4 Baldi S, Mounayer C, Piotin M. et al . Balloon-assisted coil placement in wide-neck bifurcation aneurysms by use of a new, compliant balloon microcatheter.  AJNR Am J Neuroradiol. 2003;  24 1222-1225
• 5 Mocco J, Snyder KV, Albuquerque FC. et al . Treatment of intracranial aneurysms with the Enterprise stent: a multicenter registry.  J Neurosurg. 2009;  110 35-39
• 6 Wakhloo AK, Gounis MJ, Sandhu JS. et al . Complex-shaped platinum coils for brain aneurysms: higher packing density, improved biomechanical stability, and midterm angiographic outcome.  AJNR Am J Neuroradiol. 2007;  28 1395-1400
• 7 White PM, Lewis SC, Nahser H. et al . HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS trial): procedural safety and operator-assessed efficacy results.  AJNR Am J Neuroradiol. 2008;  29 217-223
• 8 Butteriss D, Gholkar A, Mitra D. et al . Single-center experience of cerecyte coils in the treatment of intracranial aneurysms: initial experience and early follow-up results.  AJNR Am J Neuroradiol. 2008;  29 53-56
• 9 Linfante I, Akkawi NM, Perlow A. et al . Polyglycolide/polylactide-coated platinum coils for patients with ruptured and unruptured cerebral aneurysms: a single-center experience.  Stroke. 2005;  36 1948-1953
• 10 Murayama Y, Tateshima S, Gonzalez NR. et al . Matrix and bioabsorbable polymeric coils accelerate healing of intracranial aneurysms: long-term experimental study.  Stroke. 2003;  34 2031-2037
• 11 Deshaies EM, Adamo MA, Boulos AS. A prospective single-center analysis of the safety and efficacy of the hydrocoil embolization system for the treatment of intracranial aneurysms.  J Neurosurg. 2007;  106 226-233
• 12 Cloft HJ, Kallmes DF. Aneurysm packing with HydroCoil embolic system versus platinum coils: initial clinical experience.  AJNR Am J Neuroradiol. 2004;  25 60-62
• 13 Forrest MD, O’Reilly GV. Production of experimental aneurysms at a surgically created arterial bifurcation.  AJNR Am J Neuroradiol. 1989;  10 400-402
• 14 Altes TA, Cloft HJ, Short JG. et al . 1999 ARRS Executive Council Award. Creation of saccular aneurysms in the rabbit: a model suitable for testing endovascular devices. American Roentgen Ray Society.  AJR Am J Roentgenol. 2000;  174 349-354
• 15 Roy D, Milot G, Raymond J. Endovascular treatment of unruptured aneurysms.  Stroke. 2001;  32 1998-2004
• 16 Cloft HJ, Kaufmann T, Kallmes DF. Observer agreement in the assessment of endovascular aneurysm therapy and aneurysm recurrence.  AJNR Am J Neuroradiol. 2007;  28 497-500
• 17 Kai Y, Hamada J, Morioka M. et al . Evaluation of the stability of small ruptured aneurysms with a small neck after embolization with Guglielmi detachable coils: correlation between coil packing ratio and coil compaction.  Neurosurgery. 2005;  56 785-792 discussion 785–792
• 18 Gaba RC, Ansari SA, Roy SS. et al . Embolization of intracranial aneurysms with hydrogel-coated coils versus inert platinum coils: effects on packing density, coil length and quantity, procedure performance, cost, length of hospital stay, and durability of therapy.  Stroke. 2006;  37 1443-1450
• 19 Slob MJ, van Rooij WJ, Sluzewski M. Influence of coil thickness on packing, re-opening and retreatment of intracranial aneurysms: a comparative study between two types of coils.  Neurol Res. 2005;  27 (S 01) S116-S119
• 20 van Aken PJ, Emeis JJ. Organization of experimentally induced arterial thrombosis in rats from two weeks until ten months. The development of an arteriosclerotic lesion and the occurrence of rethrombosis.  Artery. 1983;  11 384-399
• 21 van Aken PJ, Emeis JJ. Organization of experimentally induced arterial thrombosis in rats: the first six days.  Artery. 1982;  11 156-173
• 22 Reul J, Weis J, Spetzger U. et al . Long-term angiographic and histopathologic findings in experimental aneurysms of the carotid bifurcation embolized with platinum and tungsten coils.  AJNR Am J Neuroradiol. 1997;  18 35-42
• 23 Spetzger U, Reul J, Weis J. et al . Endovascular coil embolization of microsurgically produced experimental bifurcation aneurysms in rabbits.  Surg Neurol. 1998;  49 491-494
• 24 Spetzger U, Reul J, Weis J. et al . Microsurgically produced bifurcation aneurysms in a rabbit model for endovascular coil embolization.  J Neurosurg. 1996;  85 488-495
• 25 Ding YH, Dai D, Lewis DA. et al . Angiographic and histologic analysis of experimental aneurysms embolized with platinum coils, Matrix, and HydroCoil.  AJNR Am J Neuroradiol. 2005;  26 1757-1763
• 26 Tsumoto T, Niimi Y, Berenstein A. Evaluation of the new HydroSoft coil in a canine model of bifurcation aneurysm.  Laboratory investigation. J Neurosurg. 2009;  111 11-16
• 27 Piotin M, Daghman B, Mounayer C. et al . Ellipsoid approximation versus 3D rotational angiography in the volumetric assessment of intracranial aneurysms.  AJNR Am J Neuroradiol. 2006;  27 839-842

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