Coil Treatment Research Articles

Application of a Stent-Graft After Initial Occlusion with Interlocking Detachable Coils for Treatment of Penetrating Atherosclerotic Ulcer of the Aorta

We read with interest the Case Report published September 2000 in CardioVascular & Interventional Radiology describing successful transcatheter embolization of a penetrating aortic ulcer using interlocking detachable coils [1]. However, follow-up CT and angiography performed in our department 24 months after the procedure confirmed recanalization of thrombosed false lumen and, again, demonstrated a pseudoaneurysm of the descending aorta (Fig. 1). To prevent rupture of the aorta, implantation of an aortic stent-graft was planned. Under general anesthesia, the right femoral artery was exposed and punctured. A 20Fr Keller-Timmerman sheath was introduced, and a noncommercial Dacron-covered spiral Z stent constructed at Nara Medical University [2], 20 mm wide and 60 mm long, was placed in the aneurysmal portion of the descending aorta. No procedure-related complications were encountered, and the patient was discharged 1 week later. Followup angiography 8 months after the procedure showed faint

Cortical Blindness, Transient and Otherwise, Associated with Detachable Coil Embolization of Intracranial Aneurysms

Cortical visual loss is a rare complication of cerebral angiography without a definitive pathophysiology. Given the rapid increase in endovascular procedures used to treat cerebral aneurysms, we explored the prevalence of this complication and whether we could add to the understanding of this disorder. We performed a retrospective review of all procedures performed with the same contrast agent and detachable coils for treatment of posterior circulation aneurysms by 1 endovascular surgery service from 1996 to 2006. All patients were evaluated before and after each procedure by a team that included a neuro-ophthalmologist. Of 137 intra-arterial treatment procedures performed for posterior circulation aneurysms, we identified 4 patients with cerebral vision loss complications. During the same time period, >500 aneurysms of the anterior cerebral circulation were treated without this complication. The visual field loss was unilateral in 2 and bilateral in 2 patients. Recovery was complete in 3 and almost normal in the fourth patient. The amount of contrast used and the duration of the procedure were similar among all patients. The 4 patients had no identified specific risk factors for developing procedure-associated occipital dysfunction, all 4 had undergone prior angiography, and 1 patient had undergone repeat coiling, without complication. The 2.9% prevalence of cerebral visual loss with endovascular coil treatment of posterior circulation aneurysms is higher than that for angiography alone. Our patients recovered well with corticosteroid and intravenous hydration treatment. Recognizing the self-limiting nature of this problem might prevent an unneeded intervention.

Large ophthalmic segment aneurysms with anterior optic pathway compression: assessment of anatomical and visual outcomes after endosaccular coil therapy

The optimal therapy for ophthalmic segment aneurysms with anterior optic pathway compression (AOPC) is undecided. Surgical results have been described, but the results of endovascular coil therapy have not been well documented. The authors retrospectively reviewed data obtained in all patients who harbored unruptured ophthalmic segment aneurysms with AOPC who underwent endovascular coil therapy at their institution. They analyzed baseline and outcome visual function, aneurysm features, extent of aneurysm closure, internal carotid artery (ICA) occlusion, additional interventions, and neurological outcome. In 17 patients (16 women), age 38 to 83 years, there were 28 affected eyes. All aneurysms were greater than 10 mm in diameter. In the initial procedures 16 of 17 patients received endosaccular coils and the ICA was preserved; in one patient the aneurysm was trapped and the ICA occluded. Patients then underwent follow up for a mean of 2.90 years (range 1 month-1 1.2 years) after the last procedure. One patient died of subarachnoid hemorrhage (SAH) 1 month postoperatively and thus no follow-up data were available for this case. Vision worsened in six patients, stabilized in four, and improved in six. Twelve patients underwent 13 subsequent procedures, including endovascular ICA occlusion in seven, repeated coil therapy in five, and optic nerve decompression in one; vision improved in 83% of these cases after ICA occlusion. A second patient died of SAH 5 months after repeated coil treatment. At the final follow up, vision had improved in eight patients (50%), stabilized in four (25%), and worsened in four (25%). In 16 patients with follow-up studies, aneurysm closure was complete in eight (50%) and incomplete in eight (50%). The authors found that in patients with ophthalmic segment aneurysms causing chronic AOPC, endosaccular platinum coil therapy, with ICA preservation, may not benefit vision and that additional procedures may be needed. Evaluation of their results suggests that endovascular trapping of the aneurysm and sacrifice of the ICA appear to result in good visual, clinical, and anatomical outcomes.

Intracranial aneurysms that repeatedly reopen over time after coiling: imaging characteristics and treatment outcome

We report imaging and clinical characteristics of patients with aneurysms that repeatedly reopened over time and were coiled three times or more during a follow-up period of 2-11 years. At angiographic follow-up of 624 of 827 aneurysms coiled between 1995 and 2005, 74 aneurysms (8.9%) reopened and were additionally coiled. During an extended follow-up, 12 aneurysms (1.5%) in 12 patients repeatedly reopened and were repeatedly coiled. Initial aneurysm sizes ranged from 15 to 30 mm. Four aneurysms contained intraluminal thrombus. Eight aneurysms were associated with subarachnoid hemorrhage and two with a mass effect, and two were incidentally discovered. The locations of aneurysms were basilar artery (eight), carotid artery (two), anterior communicating artery (one) and middle cerebral artery (one). Altogether, 49 coil treatments were performed in the 12 aneurysms, ranging from three to six coil treatments per aneurysm. Of the 49 coil treatments, 20 (41%) were performed with a supporting device. There were no procedural complications (0%, 97.5% CI 0-5.7%). The mean clinical follow-up period was 70.6 months (median 60, range 25-135 months). All 12 patients are neurologically doing well (GOS 5). Reopening was by compaction in nine aneurysms and by migration of coils into intraluminal thrombus in three aneurysms. In two aneurysms, late regrowth became apparent at 76 and 95 months after the previous coiling. Aneurysms that reopen over time and need to be coiled for a second time should be imaged at regular intervals to detect repeated reopening or regrowth. The treatment strategy of regular follow-up and additional treatments when necessary is effective and safe.

HydroCoil as an adjuvant to bare platinum coil treatment of 100 cerebral aneurysms

The overall safety of the HydroCoil, an expansile hybrid hydrogel-platinum coil, is unknown. We report a prospective observational study of our first 100 cerebral aneurysms treated with HydroCoils, focusing on safety and initial efficacy. Indications, procedural complications, clinical and angiographic outcomes were recorded. Packing density, number of coils deployed and angiographic results were compared with those in a matched control group of 100 aneurysms treated solely with bare platinum coils. HydroCoil complication rates were compared to bare platinum coil rates at our institution and in published series. Adjuvant HydroCoil treatment led to increased mean percentage aneurysm filling compared to controls (50 +/- 21% versus 27 +/- 13%, P < 0.001). Immediate posttreatment angiographic results showed significantly (P < 0.001) more complete occlusions and fewer incomplete (<95%) occlusions compared to controls. Intermediate follow-up angiograms (median 7.5 months) in 63 aneurysms showed a trend towards fewer incomplete occlusions with HydroCoil treatment. There were significantly fewer major recurrences with HydroCoil treatment compared to the control treatment (9.5% versus 22.6%, P = 0.046). In the adjuvant HydroCoil group, major recurrent aneurysms had significantly less percentage volume packing with HydroCoils than non-recurrent aneurysms (50.3 +/- 5.0% versus 65.3 +/- 18.0%, P = 0.04). There was a 12% procedural complication rate, 6% procedural morbidity and 1% mortality rate, similar to institutional and reported bare platinum coil complication rates. HydroCoils can be safely deployed with a similar complication rate to bare platinum coils. They result in improved aneurysm filling. Intermediate follow-up angiography showed significantly fewer major recurrences. Long-term follow-up is required to confirm initial improved stability.

Intrasaccular combination of metallic coils and Onyx liquid embolic agent for the endovascular treatment of cerebral aneurysms

The aim of this study was to report on a novel technique in which metallic embolization coils were combined with the Onyx liquid embolic agent in the aneurysm sac to achieve a more durable result after endovascular treatment. This therapeutic procedure was performed in selected cases in which, based on the authors' experiences, either coil embolization or Onyx alone would likely have failed. The authors report long-term clinical and angiographic follow-up results in 20 consecutive intracranial aneurysms treated using this combination for defined indications. Twenty aneurysms in 20 patients were treated with a combination of embolic coils and Onyx. Four aneurysms were giant; 13, large; and three, small. This new technique was used when standard Onyx or coil treatment with balloon assistance was determined to involve a higher possibility of recanalization, because either an adjunctive stent insertion could not be performed or the Onyx technique could not be used due to an unsuccessful seal test or intraaneurysm balloon prolapse. In one case, an adjunctive stent was placed before coil placement and Onyx deposition to control the material in the sac of the aneurysm, which had a fusiform neck. All aneurysms were completely occluded after using this technique. No clinical or technical adverse events occurred in any of the cases. Follow-up angiography was performed in all patients: 3-year studies in six patients, 2-year studies in five, and 1-year studies in nine. None of these studies demonstrated aneurysm regrowth or parent artery occlusion. The combination of the embolic coils and the Onyx liquid embolic agent provides very durable aneurysm occlusion for defined indications.

Emergency Use of Stent and rtPA with Mechanical Cloth Defragmentation for a Thromboembolic Complication during GDC Coil Treatment of an Acutely Ruptured Basilar Tip Aneurysm

Thrombotic occlusion of both posterior cerebral arteries occurred during embolization of an acutely ruptured basilar tip aneurysm. Intracranial stenting and continuous superselective infusion of rtPA was administered combined with mechanical clot fragmentation to reestablish normal vessel flow. DSA disclosed that normal vessel patency was achieved within 30 min. There were no adverse events related to rtPA administration and the patient recovered from the embolization with minor neurologic deficit as present before the procedure.

Endovascular Treatment with Platinum Coils

Recanalization after coil occlusion is a concern for long-term results of endovascular treatment. Knowledge of molecular events following coil occlusion and recanalization could help design specific strategies to promote permanent occlusion. Platinum coils were implanted into canine maxillary, vertebral or lingual arteries. Coil occlusion (treatment 1), routinely followed by recanalization was compared with two strategies to prevent recanalization: beta radiation using (32)P coils (treatment 2) and endothelial denudation, using an endovascular device, followed by coil occlusion (treatment 3). The evolution of initial complete occlusions was followed by angiography and pathology at three months. Levels of messenger RNA of vWF (von Willebrand factor), SMA (smooth muscle actin), CD14, CD31 (or PECAM-1: Platelet Endothelial Cell Adhesion Molecule-1), PDGFBB (platelet-derived growth factor), TGF-b1 (transforming growth factor), MCP-1 (macrophage chemoattractant protein), Angiopoietins, Metalloproteinases-9, 14 and inhibitors (TIMP- 2, 4) were followed by Reverse Transcription and Polymerase Chain Reaction (RT-PCR). Analyses were performed one, four, seven and 14 days after coiling, and levels of expression after the three treatments were compared using ANOVAs. Intact arteries treated with platinum coils routinely recanalize (100%), but arteries treated by denudation and coiling or with radioactive coils recanalize in only 17% and 4% respectively (P<.001). Recanalization was associated with increased levels of vWF mRNA at seven days, a finding that was not observed with denudation or radiation (P=.015). There was no other significant difference. Recanalization is associated with early vWF expression, perhaps reflecting the development of endothelialized channels through thrombus formed after coil occlusion.

Endovascular management of dural carotid–cavernous sinus fistulas in 141 patients

The purpose of this study was to evaluate the single-centre experience with transvenous coil treatment of dural carotid-cavernous sinus fistulas. Between November 1991 and December 2005, a total of 141 patients (112 female) with dural carotid-cavernous sinus fistula underwent 161 transvenous treatment sessions. The patient files and angiograms were analysed retrospectively. Clinical signs and symptoms included chemosis (94%), exophthalmos (87%), cranial nerve palsy (54%), increased intraocular pressure (60%), diplopia (51%), and impaired vision (28%). Angiography revealed in addition cortical drainage in 34% of the patients. Partial arterial embolization was carried out in 23% of the patients. Transvenous treatment comprised in by far the majority of patients complete filling of the cavernous sinus and the adjacent segment of the superior and inferior ophthalmic vein with detachable coils. Complete interruption of the arteriovenous shunt was achieved in 81% of the patients. A minor residual shunt (without cortical or ocular drainage) remained in 13%, a significant residual shunt (with cortical or ocular drainage) remained in 4%, and the attempted treatment failed in 2%. There was a tendency for ocular pressure-related symptoms to resolve rapidly, while cranial nerve palsy and diplopia improved slowly (65%) or did not change (11%). The 39 patients with visual impairment recovered within the first 2 weeks after endovascular treatment. After complete interruption of the arteriovenous shunt, no recurrence was observed. The transvenous coil occlusion of the superior and inferior ophthalmic veins and the cavernous sinus of the symptomatic eye is a highly efficient and safe treatment in dural carotid-cavernous sinus fistulas. In the majority of patients a significant and permanent improvement in clinical signs and symptoms can be achieved.

Ovarian vein ablation: coils or surgery?

Objective: The aim of this study is to compare the results, namely improvement in pelvic pain and overall satisfaction with treatment by surgery, or by coils and sclerotherapy, for pelvic congestion syndrome (PCS) when caused by ovarian vein incompetence based on ultrasound assessment. To do so requires a brief description of the diagnosis of PCS and ovarian vein incompetence, and a discussion of the indications for treatment. Methods: The same questionnaire as used for a previous surgical series in 1989–95 was used for the present study. Independent assessment of responses to the questionnaire using visual analogue scales, together with review of the clinical notes, enabled statistical evaluation of two treatment groups. Treatment was by surgery from 1989 to 1998, and by coils and sclerotherapy from January 1999 to June 2002. Obtaining demographic and presenting symptom data has enabled us to compare the two groups, as well as the results of the two treatments. Results: There was no significant difference between the demographics and presenting symptoms of surgical and coil treatment groups. Surgical and coil groups combined show a statistically significant reduction in perceived pelvic pain, and overall satisfaction with treatment. There is no difference in reduction of perceived pelvic pain or in overall satisfaction between surgical and coil treatment groups. Conclusion: Treatment based on ultrasound diagnosis is justified. Surgical ovarian vein ablation should not be considered as having been superseded by coils. The latter has some advantages but also cost implications. Long-term success of coil treatment has not yet been proven. Recanalization of the ovarian vein, if it occurs, can be treated by further coils or surgery.

Pulmonary Arteriovenous Malformations Treated with Embolotherapy: Helical CT Evaluation of Long-term Effectiveness after 2–21-Year Follow-up

To retrospectively evaluate the long-term results of transcatheter embolotherapy of pulmonary arteriovenous malformations (PAVMs) with helical computed tomography (CT). Neither institutional review board approval nor patient consent was required for this retrospective study. Thirty-eight patients underwent follow-up helical chest CT 2-21 years after successful embolotherapy of 64 PAVMs. Four outcome categories were analyzed on the basis of the PAVM morphologic changes and perfusion findings seen on CT angiograms: successful treatment (marked reduction or disappearance of the aneurysmal sac), partially successful treatment (reduced size of the aneurysmal sac and pulmonary vessels, with feeding artery[ies] less than 3 mm in diameter, deemed too small to be occluded), partially failed treatment (reduced size of the aneurysmal sac and pulmonary vessels, with feeding artery[ies] larger than 3 mm and additional embolotherapy required), and failed treatment (similar size of or interim growth in the aneurysmal sac, with unchanged or enlarged pulmonary vessels). chi(2) or Fisher exact tests were used to analyze categorical variables; Mann-Whitney rank tests were used to analyze continuous variables. P < .05 was considered to indicate statistical significance. Long-term follow-up of the 64 occluded PAVMs revealed successful treatment of 30 (47%), partially successful treatment of 18 (28%), partially failed treatment of two (3%), and failed treatment of 14 (22%) PAVMs. The overall treatment success rate was 75% (47% plus 28%). Delayed recanalization requiring repeat embolotherapy occurred in 12 (19%) cases. No relationship between failed treatment and number of coils deposited in the feeding arteries was found. The frequency of gastrointestinal tract and/or hepatic arteriovenous fistulas at initial diagnosis (P = .01) and/or the interim development of pulmonary hypertension with or without heart failure (P = .01) was significantly higher in patients with at least one PAVM for which embolotherapy failed (n = 9) than in patients who underwent successful or partially successful embolotherapy of all PAVMs (n = 29). Long-term CT follow-up of initially successfully treated PAVMs revealed successful embolotherapy of 75% and partially or completely failed embolotherapy of 25% of PAVMs.

Repeated Endovascular Coil Occlusion in 350 of 2759 Intracranial Aneurysms: Safety and Effectiveness Aspects

Evaluation of the safety and effectiveness of endovascular retreatment of intracranial aneurysms with detachable coils. Retrospective analysis of clinical outcome as well as angiographic studies both before and after coil retreatment. The indication for retreatment was based on either inadequate occlusion after previous treatment or recurrent perfusion of the aneurysm. A total of 2759 intracranial aneurysms in 2360 patients were treated by endovascular coil occlusion. Of those, 350 (12.3%) aneurysms underwent a second treatment, and 94 (3.4%) aneurysms underwent three or more treatment sessions. The second treatment sessions were performed an average of 27.2 months after the previous procedure. The third and following treatment sessions were conducted an average of 25.3 months after the previous procedure. Initial treatment resulted in 100% occlusion in 63.7% of aneurysms. One hundred percent occlusion was achieved in only 46.9% of the second and 35.2% of the third and following sessions. Stent-assisted coil treatment was used in 5.6% of initial, 28.0% of second, and 20.7% of third and following sessions. Initial treatment sessions were uneventful in 83.2% of cases, second sessions in 86.9% of cases, and third and following sessions in 87.6% of cases. The morbidity-mortality rate for 495 retreatment sessions was 2.2% (n = 11). The natural course of aneurysm remnants or recurrent aneurysm perfusion after coil treatment is not completely understood. The low risk of bleeding from partially filled aneurysms must be balanced against the procedure-related risks of retreatment. Great caution is recommended for the treatment of asymptomatic recurrent aneurysms.

Angiographic and clinical results in 316 coil-treated basilar artery bifurcation aneurysms

The aim of this study was to analyze the effect of the endovascular treatment of basilar artery (BA) bifurcation aneurysms and to compare the results with those published by other neuroendovascular teams. The authors performed a retrospective analysis of 316 aneurysms of the BA bifurcation that had been treated using endovascular coil occlusion between November 6, 1992, and February 12, 2005. After the initial embolization procedure, a 90 to 100% occlusion rate was achieved in 86% of the aneurysms. No complication was evident in 80% of the lesions, although periprocedural aneurysm rupture (3.2%) and thromboembolic events (12.3%) were the most frequent complications. Clinical outcome according to the Glasgow Outcome Scale (GOS) was a score of 5 or 4 in 77%, 3 in 11%, 2 in 5%, and 1 in 7% of patients. Initial follow-up angiography studies were obtained in 56% of patients at a mean of 19 months posttreatment and demonstrated a 90 to 100% occlusion rate in 70%. No recurrence was seen on 65% of the aneurysms. Coil compaction was evident on 24% of the follow-up angiograms. A second treatment was performed on 48 aneurysms (15%) a mean of 27 months after the first therapeutic session and resulted in 90 to 100% occlusion in 83% of the lesions. Complications were encountered in 19% of the aneurysms. Rupture did not occur during any of the procedures. Clinical outcome was rated as GOS Score 5 or 4 in 83% of the patients and Grade 3 in 17%. During a cumulative clinical follow up of 821 years in 237 patients, 182 patients (81%) were independent (GOS Score 5 or 4), 33 (14%) were dependent (GOS Score 3), eight (3%) were in a vegetative state, and two (1%) had died. Clinical outcome was significantly worse after previous aneurysm rupture and following procedural complications. These results are within the range of published data for coil treatment of BA tip aneurysms and confirm both the safety and efficacy of this endovascular treatment method.

ISAT and ISUIA: The Impact on Informed Consent

The International Subarachnoid Aneurysm Trial (ISAT) was a multicenter randomized trial that compared the safety and efficacy of endovascular coil treatment versus surgical clipping for the treatment of ruptured brain aneurysms. To be eligible for enrollment in the ISAT trial, each patient had to be deemed equally suitable for either coiling or clipping. The investigators used the term "clinical equipoise" to describe this balance. This study more than any other has set the playing field for the future of interventional radiology/endovascular neurosurgery politics.

Analysis of Cost Related to Clinical and Angiographic Outcomes of Aneurysm Patients Enrolled in the International Subarachnoid Aneurysm Trial in a North American Setting

The goal of this study was to compare, in a North American setting, the cost-effectiveness of neurosurgical clipping versus endovascular coiling treatment of ruptured intracranial aneurysms. A secondary goal was to assess the clinical outcomes of patients enrolled into the International Subarachnoid Aneurysm Trial (ISAT) from the largest contributing North American center. Of 230 patients with ruptured intracranial aneurysms, 62 were randomized into ISAT at our institution. Of these, 30 were randomized to endovascular coiling and 32 to neurosurgical clipping. For these, we evaluated the costs of treatment related to all aspects of the inpatient stay, the clinical outcomes at 2 months and at 1 year using the modified Rankin Scale, and the radiological outcomes at 6 months after Guglielmi detachable coiling. There were no significant differences in the total cost of treatment between the endovascular group and the neurosurgical clipping group. The benefits of apparent decrease in length of stay in the endovascular group were offset by higher procedure costs. There were no significant differences in clinical outcomes at 2 months and at 1 year. At 6 months after coiling, 15 (50%) of 30 aneurysms were completely obliterated, and 19 (63%) of 30 were angiographically stable. The high procedure costs of endovascular coiling tended to offset apparent reductions in length of stay. Long-term follow-up is indicated both for costs incurred after initial treatment and for clinical outcome in patients with incompletely obliterated aneurysms.

Optimal scheduling method for a bell-type batch annealing shop and its application

The production scheduling for a bell-type batch annealing process in heat treatment of steel coils is a typical multi-machine multi-stage re-entrant problem with complex constraint of resources including energy source. It is very difficult to build its mathematical model due to the large number of constraints in the process. This paper proposes an optimal scheduling method for the bell-type batch annealing process that combines an improved genetic algorithm with discrete event simulation techniques. The optimal scheduling method developed in this paper has been applied to the annealing shop in Shanghai Baosteel Yichang Sheet Co. Ltd, China, for nearly 2 years. The industrial application result shows that the proposed optimal scheduling method improves production efficiency and gains economic benefits.

Surgical Clipping of a Recurrent Small Saccular Aneurysm After Repeated Coil Embolization-Case Report-

A 59-year-old healthy woman presented with sudden onset of severe headache. Computed tomography and digital subtraction angiography (DSA) demonstrated subarachnoid hemorrhage (grade I according to the Hunt and Hess classification) due to a ruptured small right posterior cerebral artery (PCA) aneurysm. The ruptured PCA aneurysm was completely embolized with three Guglielmi detachable coils (GDCs). However, follow-up DSA 3 months after the initial coiling confirmed refilling of the aneurysm. The aneurysm was successfully re-embolized with two GDCs. Follow-up DSA 10 months later revealed regrowth of the aneurysm. Surgical clipping was performed without compromising the parent vessels. Long-term angiographic follow up is necessary even in patients with small saccular aneurysms which are apparently completely embolized by endovascular coil treatment.

On the influence of heavy warm reduction on the microstructure and mechanical properties of a medium-carbon ferritic–pearlitic steel

Abstract The current study on a medium-carbon steel (0.36 % C) with deformation-induced spheroidized cementite produced by heavy warm deformation (HWD) was carried out in order to investigate an alternative microstructural route when compared to conventional quenching and tempering (QT) or soft annealing (SA) processes. After austenite deformation, the HWD samples were cooled and heavily deformed at temperatures below the γ–α transformation followed by a simulated coiling treatment. In particular, the study addresses the influence of adiabatic heating due to the heavy deformation on the microstructure and properties. The mechanical properties after the various treatments show that the strength–ductility relation after HWD and QT are superior to those after continuous cooling (CC) or soft annealing (SA). In the microstructures obtained from the CC and SA treatments we observed lamellar pearlite which deteriorated the mechanical properties. A similar effect was observed after the adiabatic HWD treatment, wh...

Coil treatment of a fusiform upper basilar trunk aneurysm with a combination of ?kissing? neuroform stents, TriSpan-, 3D- and fibered coils, and permanent implantation of the microguidewires

Endovascular coil occlusion of fusiform intracranial aneurysms without sacrifice of the parent artery can be technically challenging. Bridging of wide aneurysm necks with stents is common practice for side-wall aneurysms but is less frequently used for bifurcation aneurysms. We describe the technical aspects of the successful coil occlusion of a fusiform aneurysm of the upper basilar trunk, with preservation of the parent vessel. The procedure comprised the following steps: (a) stenting of the left V1- and proximal V2 segments; (b) simultaneous deployment of two Neuroform stents from both P1 segments down to the basilar artery ("kissing" stents) (c) using a TriSpan device to hold (d) three-dimensional electrolytically detachable coils in place and (e) filling the aneurysmal lumen mainly with fibered electrolytically detachable coils; and finally (f) cutting the extracorporeal part of both microguidewires below the skin level in both groins, leaving the microguidewires as they were used for the deployment of the stents in place, thus reaching from both P2 segments down to the basilar artery and further proximally.

Interaction of hydrogen with carbon coils at low temperature

Hydrogen was adsorbed on carbon coils under 10 MPa hydrogen gas at liquid nitrogen temperature. The equilibrium pressure of hydrogen desorbed from the as-grown carbon coils with an amorphous structure was three to four times greater than those of multiwall carbon nanotubes (MWNT) and active carbons (AC). The heat treatment of the carbon coils at 850 °C contributed to an increase in hydrogen adsorption by 20% compared to the as-grown carbon coils. On the other hand, the adsorption of hydrogen gas on the carbon coils decreased significantly after heat treatment at a temperature higher than 1000 °C due to formation of capsule-like carbon composed of 10–20 layers on the surface of the carbon coils.