In Situ Beta Radiation to Prevent Recanalization After Coil Embolization of Cerebral Aneurysms

Abstract

Background and Purpose-Endovascular treatment of cerebral aneurysms, a minimally invasive alternative to surgery, is too often followed by recanalization and recurrences. The purpose of this work was to assess if in situ beta radiation can inhibit recanalization after coil embolization. Methods-Radioactive platinum coils ( 32 P-coils) were produced by ion implantation of 32 P. A single-coil arterial occlusion model was used to compare angiographic and pathological results at 1 to 12 weeks after nonradioactive and 32 P-coil embolization of maxillary, cervical, and vertebral arteries in 26 dogs. Coils of varying activities were used and results compared to define the minimal activity required to inhibit recanalization. Similar experiments were performed in 16 porcine maxillary and lingual and 8 rabbit axillary arteries. Results of 32 P-coil embolization of bifurcation aneurysms were then compared with embolization with nonradioactive coils in 12 dogs at 3 months. Results-Nonradioactive coil embolization of canine arteries led to occlusion at 1 week, followed by recanalization at 2 weeks, which persisted at 3 months in all cases. 32 P-coils, ion-implanted with activities above 0.13 Ci/cm, led to persistent occlusion at 3 months in 80% of arteries.32 P-coils ion-implanted with the same activity inhibited recanalization in porcine and rabbit arteries. Bifurcation aneurysms treated with 32 P-coils had better angiographic results at 3 months (Pϭ0.006) than aneurysms treated with nonradioactive coils. Arteries occluded were filled with fibrous tissue at 3 months. Aneurysms embolized with 32 P-coils showed more complete neointimal coverage of the neck, without recanalization, as compared with aneurysms treated with nonradioactive coils. Conclusion-In

The Woven EndoBridge: A New Aneurysm Occlusion Device

“…Well-described in the literature, coil compaction is particularly a problem in high-flow (eg, terminal, bifurcation) aneurysms, resulting in high recanalization and retreatment rates. [27][28][29][30] Finally, the company has an improved second generation of this device that is undergoing preclinical testing.…”

Role of the Endothelial Lining in Persistence of Residual Lesions and Growth of Recurrences After Endovascular Treatment of Experimental Aneurysms

“…Alternatively, the embolic agent could be designed to somehow inhibit or delay the invasion of endothelial cells in favor of mesenchymal cells. 13 …”

Effects of Endothelial Injury on the Rate of Thrombus Organization in Canine Carotid Arteries Occluded with Microcoils

“…This is consistent with the slow rate of endoluminal thrombus organization that occurs in large human cerebral aneurysms, and experimental canine vein pouch aneurysms [3][4][5][6]25 . Other investigators have used lasers to perform external photocoagulation of surgically exposed aneurysms in humans and experimenwww.centauro.it Interventional Neuroradiology 9: [7][8][9][10][11][12][13][14][15][16][17][18][19]2003 tal animals [26][27][28] . Those studies demonstrated fibroblastic obliteration and neoendothelialization of laser photocoagulated aneurysmal ostia within three to six weeks.…”

“…Although these examples represent forms of mechanical injury, experimental studies and clinical experience have both suggested that the healing response ofthe arterial wall is non-specific [14][15][16] . The ability of endothelial injury to promote endovascular healing was recently illustrated in a study of canine vein pouch aneurysms embolized with P 32 ion implanted microcoils 17 . The beta emitting P 32 coils prevented recanalization of embolized aneurysms and promoted formation of a thick neointimal covering over the necks of embolized aneurysms 17 .…”

“…The ability of endothelial injury to promote endovascular healing was recently illustrated in a study of canine vein pouch aneurysms embolized with P 32 ion implanted microcoils 17 . The beta emitting P 32 coils prevented recanalization of embolized aneurysms and promoted formation of a thick neointimal covering over the necks of embolized aneurysms 17 . Although the mechanism of this effect remains unproven, the dosimetry profile of the P 32 device is consistent (0.7 mg/Kg), ketamine (10 mg/Kg), and atropine (0.016 mg/Kg).…”