Endovascular coils

Henkes H, Lowens S, Preiss H, Reinartz J, Miloslavski E, Kuhne D. A new device for endovascular coil retrieval from intracranial vessels alligator retrieval device. Am J... 

Late rebleeding occurs in 2-3% of patients in the first 10 years after clipping of an aneurysm, half of such bleeds being caused by newly developed aneurysms. After endovascular coiling, the long-term risks are unclear, being recorded at 0.7% between one month and one year in ISAT (Molyneaux et al. 2005) and at 2-3% in one month to four years in a Dutch cohort (Sluzewski et al. 2005). 

For subarachnoid hemorrhage surgical clipping of the causative aneurysm or resection of the arteriovenous malformation is the mainstay of treatment. Endovascular coiling of the aneurysm can also be performed. Post-operative infection (either brain or respiratory) is an uncommon complication and not believed to be any more common than after other invasive surgical procedures. Hypervolemic-hemodilution and hypertensive (HHH) therapy is used to prevent spasm. There may be a role for anti-inflammatory measures for the prevention of vasospasm and delayed cerebral ischemia, as shown in a recent pilot study of patients treated with statins (Lynch et al., 2005). 

Matrix detachable coils (Boston Scientific Neurovascular) are another example of modified endovascular coils, employing a stainless steel delivery wire coated with a bioabsorbable copolymer of 90% polyglycolide and 10% polylactide. In a study by Murayama et al. (2003), matrix detachable coils were shown to accelerate the rate of aneurysm healing in swine aneurysm models, specifically by promoting the formation of a thick neointimal layer at the aneurysm neck more quickly bare platinum coils (Murayama et al, 2003). Taschner et al. (2005) evaluated the use of Matrix detachable coils in 25 patients with intracranial aneurysms. Again, stable emboUzed aneurysms were achieved over a six-month period, but only when Matrix coils were used in conjunction with bare platinum coils (Taschner et al, 2005). 

International Subarachnoid Aneurysm Trial (ISAT) Collaborative Group. (2002) International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms a randomised trial. The Lancet, 360, 1267-1274. 

Abrahams JM, Forman MS, Grady MS, Diamond SL (2001) Biodegradable polyglycolide endovascular coils promote wall thickening and drug delivery in a rat aneurysm model. Neurosurgery 49 1187-1193... 

Malek AM, Halbach VV, Phatouros CC, et al. (2000) Balloon-assisted technique for endovascular coil embolization of geometrically difficult intracranial aneurysms. Neurosurgery 46 1397-1406... 

Fig. 5. 2a-f. Dissection of the right internal carotid artery with extracranial enlarging pseudoaneurysm. a Contrast-enhanced MR angiography demonstrating the aneurysm at the extracranial ICA. b Conventional DSA, oblique view, c CT angiography, sagittal reformation reveals the small aneurysm neck, d Conventional DSA before and (e,f) after endovascular coil embolization demonstrating aneurysm occlusion with preservation of the internal carotid artery... 

ISAT was a randomised, prospective, international, controlled trial of endovascular coiling vs surgical clipping for a selected group of patients with ruptured intracranial aneurysms deemed suitable for both types of therapy. Most patients were treated at high-volume centres in the United Kingdom, with the remainders from other European countries, Australia, Canada, and the United States. The primary endpoint was patient outcome, defined as a modified Rankin scale of 3-6 (dependent or deceased) at 1 year. The primary hypothesis was that endovascular treatment would reduce the proportion of patients dependent or deceased by 25% at 1 year. A total of 9559 patients with SAH were screened... 

Regli L, Uske A, de Tribolet N (1999) Endovascular coil placement compared with surgical clipping for the treatment of unruptured middle cerebral artery aneurysms a consecutive series. J Neurosurg 90 1025-1030... 

Fig. 10.1. Correct patient positioning for intracranial scans, light box indicates the scan volume, eye-lenses outside of scan volume. Note the titanium coils after endovascular coil embolization of an aneurysm at the anterior communication artery (ACoA)...

Levy E, Koebbe CJ, Horowitz MB et al. (2001) Rupture of intracranial aneurysms during endovascular coiling management and outcomes. Neurosurgery 49 807-811... 

Molyneux A J. Kerr R S, Yu L M et al. (2005) International subarachnoid aneurysm trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2,143 patients with ruptured intracranial aneurysms a randomised comparison of effects on survival, dependency, seizures, rebleeding, subgroups, and aneurysm occlusion. Lancet 3-9 366 809-917 Richter G, Engelhorn T, Struffert T et al. (2007) Flat panel detector angiographic CT for stent-assisted coil embolization of broad-based cerebral aneurysms. Am J Neurora-diol 28 1902-1908... 

Matsuura JH, Rosenthal D, Jerius H, Clark MD, Owens DS (1997) Traumatic carotid artery dissection and pseudoaneurysm treated with endovascular coils and stent. J Endo-vasc Surg 4 339-343... 

Higashida RT, Smith W, Gress D, Urwin R, Dowd CF, Balousek PA, Halbach VV (1997) Intravascular stent and endovascular coil placement for a ruptured fusiform aneurysm of the basilar artery. Case report and review of the literature. J Neurosurg 87 944-949... 

Endovascular coiling is preferred to surgical clipping for the treatment of intracranial aneurysms, which affect between 2% and 6% of the world population (Ahuja et al., 1993 Horowitz, Samson, Purdy, 1997). Hampikian et al. (2006) evaluated the feasibility of using a novel block copolymer polyurethane, CalomerT, to replace platinum in aneurysm coils. The thermomechanical and radiographic properties were tested for both SMP polyurethane and a composite made of SMP with 3% metal filler. The intracranial aneurysm helical coils made from the SMP composite were successfully deployed inside an aneurysm model with simulated fluid forces. The scientists at Lawrence Livermore National Laboratory also developed a laser-activated SMP foam device for aneurysm occlusion (Maitland et al., 2007). Their SMP was synthesized from HDI, HPED, and TEA, similar to that used in the clot removal device (Wilson et al., 2005). In their preliminary in vitro basilar aneurysm model study, the... 

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