Bare Platinum Coils Research Articles

Endovascular Treatment With Bare Platinum Coils for Middle Cerebral Artery Aneurysms

Middle cerebral artery (MCA) aneurysms often have unfavorable anatomical characteristics preventing successful endovascular occlusion. We reviewed the outcomes of our series of endosaccular embolization of MCA aneurysms using bare platinum coils, angiographic images, and medical records. Immediate and follow-up angiographic results were categorized as complete occlusion, residual neck, and residual flow. Follow-up angiographic changes were categorized as unchanged, minor or major recurrence, and progressive thrombosis. Between December 2001 and August 2007, 112 patients with 113 MCA aneurysms underwent endovascular treatment, of whom 60 presented with subarachnoid hemorrhage (SAH) due to MCA aneurysm rupture. Immediate angiographic outcomes for 103 aneurysms revealed complete occlusion in 64, residual neck in 21, residual flow in 18, and failed embolization in 10. Follow-up angiography of 70 aneurysms demonstrated 41 unchanged, 10 minor recurrences, 12 major recurrences, 7 progressive thromboses, and no bleeding of coil embolized aneurysms. Outcomes of 58 SAH patients treated endovascularly revealed 45 good recovery and moderate disability, 10 severe disability or persistent vegetative state, and 3 deaths. Forty-four of the 45 patients with unruptured aneurysms treated endovascularly had no changes in their neurological status. One of 5 patients with complications had permanent morbidity. For patients with MCA aneurysms suitable for endovascular surgery, bare platinum coil embolization can be performed with acceptable low morbidity and mortality rates, with a lower risk of postprocedural aneurysmal bleeding.

The Hydrodynamic Effect of Bare Platinum Coils versus Hydrogel-Coated Platinum Coils

HydroCoils (HES) were designed to obtain a better initial aneurysm occlusion and increased durability of endovascular treatment. We compared the immediate hydrodynamic effects of HES versus bare platinum coils (Guglielmi detachable coils, GDC). Intra-aneurysmal pressure and flow were measured with a 0.014 inch guidewire mounted transducer in silicone aneurysms mounted onto a pulsatile flow phantom before and after consecutively coiling with GDC and HES. We evaluated flow using the thermodilution technique along with changes in steady pressure and sudden increases in pressure. We also considered the effect of the coils on the transmission of pressure from the parent artery to the dome of the aneurysm. Intra-aneurysmal pressure remained unchanged after maximal packing with either GDC or HES. Sudden increases in pressure were less attenuated within the aneurysm after coiling with HES. In spite of HES obtaining a much higher percentage filling volume in the aneurysms, GDC equivalently virtually abolished intra-aneurysmal flow apart from in one instance where there was significant persistent flow after coiling with GDC. The effects of HES in terms of pressure and flow attenuation within the aneurysm could hence not be proven superior to GDC.

IMMEDIATE AND MIDTERM OUTCOMES OF PATIENTS WITH CEREBRAL ANEURYSMS TREATED WITH MATRIX1 AND MATRIX2 COILS

Recanalization after coil embolization of cerebral aneurysms remains a limitation of this progressively accepted modality. The Matrix detachable bioabsorbable coil (Boston Scientific Neurovascular, Natick, MA) was developed to overcome this limitation. We report a single-center experience using first- and second-generation Matrix coils. Immediate and midterm angiographic outcomes of 235 consecutive patients with 250 aneurysms treated with Matrix coils were reviewed retrospectively. The first 16 aneurysms included in the postmarket Acceleration of Connective Tissue Formation in Endovascular Aneurysm Repair (ACTIVE) study were treated exclusively with the Matrix coil, as per protocol. The next 234 aneurysms were treated in combination with bare platinum coils, stents, and the balloon-assisted technique. First-generation Matrix coils were used in 155 aneurysms (Matrix1 group) and second-generation Matrix coils were used in 79 aneurysms (Matrix2 group). Outcomes of the 3 groups were compared. Immediate complete obliteration was achieved in 12.5% of the ACTIVE group aneurysms, 32.9% of the Matrix1 group, and 43.0% of the Matrix2 group. Overall, 87 (34.8%) aneurysms were completely occluded acutely. Procedure-related morbidity and mortality were 2.4 and 0%, respectively. Follow-up (median, 7.9 months) angiograms were obtained for 186 (74.4%) aneurysms. Complete obliteration of aneurysms was confirmed in 26.7% of the ACTIVE group, 53.4% of the Matrix1 group, and 64.2% of the Matrix2 group. Recanalization was observed in 33.3% of the ACTIVE group, 16.9% of the Matrix1 group, and 9.4% of the Matrix2 group. The overall recanalization rate was 16.1%. Use of Matrix2 coils resulted in improved mechanical performance and anatomic outcome compared with Matrix1 coils. However, practitioners must be familiar with the mechanical characteristics of the Matrix coils, which are different from those of bare platinum coils.

Intracranial Aneurysms Coiling With Matrix

We report our experience using Matrix coils in coiling of cerebral aneurysms. Clinical and angiographic outcomes of 152 patients (165 aneurysms) treated exclusively with Matrix coils were retrospectively analyzed. There were 74 ruptured aneurysms (44.8%) and 91 unruptured (55.2%). After coiling, 84 (50.9%) aneurysms were occluded, 38 (23.0%) aneurysms had a neck remnant, and 43 (26.1%) aneurysms had a sac remnant. Packing ranged from 10% to 49% (mean and median, 27%). Overall treatment-induced morbidity was 6.6% and mortality was 1.3% (10 of 152 to 2 of 152, respectively). One hundred fifteen (69.7%) aneurysms were followed, disclosing 42 (36.5%) recurrences at a mean period of 9 months (median, 6 months; range, 1 to 28 months). The recurrence rate for small aneurysms (<10 mm) was 28 (31.1%) of 90, whereas for larger aneurysms (>/=10 mm), the recurrence rate was 14 (56.0%) of 25 (P=0.0336). When packing was </=25%, the recurrence rate was 44.4%, whereas for aneurysms with packing >25%, the recurrence rate was 29.8% (P=0.1588). Recurrence rate was not correlated to packing. Ruptured aneurysms recurred more frequently than unruptured aneurysms (P=0.0004). Matrix coils provided no better recanalization rates than those reported previously for bare platinum coils.

Endovascular Histologic Effects of Ultrathin Gold- or Vitronectin-Coated Platinum Aneurysm Coils in a Rodent Arterial Occlusion Model: A Preliminary Investigation

Novel stratagems to improve the efficacy of platinum coils in occluding cerebral aneurysms have primarily involved coating coils with materials thought likely to provoke more desirable histologic reactions. No investigations to date, however, have evaluated the utility of gold or vitronectin coatings, despite known endovascular histologic effects of these agents, which may be favorable for treating cerebral aneurysms. This study was conducted to evaluate the degree of endovascular histologic change associated with ultrathin gold- or vitronectin-coated platinum coils. It was hypothesized that such coatings would increase intra-aneurysmal intimal hyperplasia and the degree of luminal occlusion compared with standard platinum coils. The ligated carotid artery rat model was used to study 4 different aneurysm coil conditions: no coil (sham-surgery controls), uncoated platinum coil, and gold- or vitronectin-coated platinum coil. Two weeks postimplantation, the aneurysms were harvested and stained with hematoxylin-eosin. Slides were evaluated for the degree of neointimal response by a pathologist blinded to treatment. Additional quantitative evaluation was performed blindly by using the ratio of intimal-to-luminal cross-sectional area. A gold- or vitronectin-coated platinum aneurysm coil produced a statistically significant increase in neointimal response compared with a sham (no coil). Arterial segments treated with gold-coated platinum coils also demonstrated a statistically significant 100% increase in neointimal response compared with those treated with bare platinum coils. In concordance with our hypothesis, ultrathin coatings of gold provoked a neointimal response and degree of luminal occlusion greater than that of plain platinum aneurysm coils in a rat arterial occlusion model.

DELAYED VISUAL DEFICITS AND MONOCULAR BLINDNESS AFTER ENDOVASCULAR TREATMENT OF LARGE AND GIANT PARAOPHTHALMIC ANEURYSMS

Paraophthalmic aneurysms may exert mass effect on the optic apparatus. Although surgical clipping and endovascular coiling of these aneurysms can be complicated by immediate postoperative visual deterioration, endovascular coil embolization has the unique risk of visual complications later (>24 h) in the perioperative period. Six patients with a delayed onset of vision loss after technically successful coil embolization of paraophthalmic region aneurysms were identified. All available clinical, angiographic, and cross sectional imaging for these patients, in addition to histopathological data, were reviewed. Six patients who underwent endovascular treatment of paraclinoid aneurysms at our institutions developed delayed postoperative visual decline. Four were treated with combination hydrogel-coated and bare platinum coils, one with hydrogel-coated coils, and one with bare platinum coils. Three patients presented with some degree of visual impairment caused by their aneurysms. Catheter angiography performed after the visual decline revealed no etiology in any of the cases. Magnetic resonance imaging was performed in all patients and was unremarkable in two. At follow-up, two had improved, three remained unchanged, and one patient died before any follow-up assessment of her vision. Both acute and delayed visual disturbances can present after the endovascular treatment of carotid artery paraophthalmic aneurysms. Delayed visual deterioration can be observed up to 35 days after embolization. Although the cause is still undefined, it is likely that the more delayed visual deterioration can be attributed to progression of mass effect and/or perianeurysmal inflammatory change. Our case series raises the possibility that this phenomenon may be more likely with HydroCoil (HydroCoil Embolic System; MicroVention, Aliso Viejo, CA). This possibility should be taken into account by neurointerventionists when selecting a coil type to treat large paraophthalmic aneurysms.

Hydrogel coil–related delayed hydrocephalus in patients with unruptured aneurysms

Because of high recanalization rates associated with wide-necked intracranial aneurysms treated with bare platinum coils, hydrogel coils (HydroCoil, MicroVention, Inc.) have been developed. Hydrogel coils undergo progressive expansion once exposed to the physiological environment of blood and increase overall aneurysm filling. The authors retrospectively reviewed their series of patients with unruptured aneurysms treated between 1998 and 2006 and who underwent placement of bare platinum and hydrogel coils for cerebral aneurysms. They examined the incidence of delayed hydrocephalus as related to coil type. In a subgroup of patients in which preand postprocedure CT and MR imaging studies were available, the authors quantitatively analyzed the ventricular size change after hydrogel coils were placed. Four of 29 patients treated with hydrogel coils developed symptomatic hydrocephalus 2-6 months after the intervention compared with 0 of 26 treated with bare platinum coils alone. The difference in ventricular size between the subgroups in which pre- and postprocedure imaging was performed was found to be statistically significant (p < 0.05). All 4 HydroCoil-treated patients in whom hydrocephalus developed required placement of a shunt. A 14% incidence (95% confidence interval 3.9-31.7%) of hydrocephalus in patients with unruptured aneurysm undergoing embolization with hydrogel coils was discovered. This incidence is much higher than previously reported. The mechanism by which hydrogel coils may induce hydrocephalus remains poorly understood.

Treatment of Arteriovenous Malformations with Hydrocoils in a Swine Model

Arteriovenous malformations (AVM) of the brain are the most common symptomatic congenital vascular malformation of the central nervous system, with significant associated morbidity and mortality. This study compared the feasibility and efficacy of treating AVMs by embolization with hydrocoils with similar treatment with bare platinum coils, using the swine rete mirabile as a model. A right carotid-jugular fistula was created in ten swine.A microcatheter was positioned into the rete mirabile, which was unilaterally (contralateral to the fistula) embolized with hydrocoils in six and bare platinum coils in four swine. Angiograms were evaluated during and immediately after embolization. Embolization with complete cessation of bloodf low in the unilateral rete mirabile was achieved in all animals treated with hydrocoils. The number of coils needed varied from four to seven (diameter 2-4 mm; mean coil length 22.3 cm). Embolization with platinum coils of similar number (seven) and slightly longer length (mean 37.75 cm) had a minimal effect on blood flow, resulting in occlusion of only small compartments. No immediate complications were noted with either coil. Hydrocoils are more effective in achieving embolization than bare platinum coils. Expansion of the hydrocoil over only a few minutes allows precise placement and stabilization of the coil before detachment. Hydrocoilscan be safely placed into small vessels. This approach may be particularly useful to decrease the flow rate, as a first stage of AVM embolizationin high flow AVMs that contain arteriovenous fistulae.

Wall enhancement, edema, and hydrocephalus after endovascular coil occlusion of intradural cerebral aneurysms

Symptomatic local inflammation, aseptic meningitis, and hydrocephalus are reported in a group of patients treated with second generation/modified platinum coils. The purpose of this study was to define the frequency and determinants of magnetic resonance (MR) imaging findings of aneurysm wall enhancement, perianeurysmal edema, and hydrocephalus in a cohort of coil-embolized intradural cerebral aneurysms treated with bare platinum or modified platinum coils (Matrix or HydroCoils). The authors retrospectively reviewed 359 Gd-enhanced MR follow-up studies of 181 treated aneurysms (125 ruptured) for mural enhancement. Univariate and multivariate logistic regression analyses were used to define mural enhancement associations with demographic, clinical, angiographic, treatment, and follow-up data. Embolization-related edema and hydrocephalus were defined in 95 MR imaging studies of 56 unruptured aneurysms. Asymptomatic wall enhancement was observed in lesions treated with all coil types, occurring in 21 (18.6%) of 113 bare platinum coil-treated aneurysms. Independent associations were HydroCoil treatment (odds ratio [OR] 9.75, 95% confidence interval [CI] 3.45-30.75) and increasing aneurysm size (OR 3.58, 95% CI 1.99-6.95). Five (8.9%) unruptured aneurysms had asymptomatic de novo edema, and 3 (5.3%) demonstrated hydrocephalus; all had been treated with HydroCoils. Hydrocephalus presentation was delayed (8-31 months) and symptomatic in 2 patients. Asymptomatic aneurysm wall enhancement occurred in 18.6% of embolizations performed with bare platinum coils, and probably represents a normal healing response. Perimural edema and hydrocephalus were observed only in patients treated with HydroCoils, but have been reported in patients treated with other modified platinum coils. These symptoms appear to represent an exaggerated inflammatory response during aneurysm healing. Increased vigilance for delayed hydrocephalus is required. Judicious clinical use of modified platinum coils is warranted until results of randomized trials are published.

Single-center Comparison of Bioactive versus Bare Platinum Coils for the Endovascular Treatment of Intracranial Aneurysms

Single-center Comparison of Bioactive versus Bare Platinum Coils for the Endovascular Treatment of Intracranial Aneurysms

Endovascular treatment of intracranial aneurysms with bioactive Cerecyte coils: effects on treatment stability

The Cerecyte coils were developed to improve long-term stability of embolized cerebral aneurysms by producing an increased fibrous reaction over the neck of the aneurysms. We report our preliminary clinical experience with mid-term follow-up. Seventy-eight consecutive patients with 84 intracranial aneurysms treated exclusively with Cerecyte coils were included in this study. Forty-eight aneurysms were ruptured and 36 were incidental. Twenty-two aneurysms were small with (<10 mm) small neck (<4 mm) (SASN); 55 were small with wide neck (>or=4 mm) (SAWN); six were large (10-25 mm) (L); and one was giant (G) (>25 mm). The embolization technique was the same with that in standard bare coiling. Immediate post-procedure angiography demonstrated complete aneurysm occlusion in 69%, neck remnant in 29.8% and incomplete occlusion in 1.2%. Follow-up angiography was obtained in 80 aneurysms in a period of time ranging from 6 months to 2 years. The overall recanalization rate was 11.3%, and the re-treatment rate was 6.3%; in the subgroup analysis, recanalization rates were 4.5% in S/S; 9.8% in S/W; and 33.3% in large aneurysms. The only giant aneurysm also showed recanalization. Procedure-related morbidity and mortality rates were 2.6% and 1.3%, respectively. Our midterm results showed a relatively low rate of recurrence compared to those reported for platinum coils with morbidity and mortality rates comparable to those with standard bare platinum coils. The efficacy of Cerecyte coils in the long term will be specifically addressed by the ongoing randomized Cerecyte coil trial.

Results of 101 Aneurysms Treated with Polyglycolic/Polylactic Acid Microfilament Nexus Coils Compared with Historical Controls Treated with Standard Coils

Polyglycolic/polylactic acid (PGLA) addition to bare platinum coils is intended to reduce the reopening rate of coiled intracranial aneurysms. Nexus coils are standard complex platinum coils with interwoven PGLA microfilament threads. We present the clinical results of 101 intracranial aneurysms treated with Nexus coils. Results of coiling of 101 aneurysms treated with Nexus coils were compared with our results of coiling of 120 aneurysms with Guglielmi detachable coils (GDC 10) and 115 with Trufill coils treated between May 2003 and December 2004 with the same treatment protocol. Rate of complications, mean aneurysmal volume, packing attenuation, incomplete aneurysmal occlusion at 6 months, and rates of retreatment were compared. Initial occlusion in aneurysms treated with Nexus coils was (near) complete in 97 aneurysms and incomplete in 4 aneurysms. There were no permanent procedural complications (0/95 patients, 0%; 97.5% CI, 0.0% to 3.3%). Mean aneurysmal volume was 180.2 mm(3) (range, 5-1624 mm(3)). Mean packing was 19.4% (range, 7.5% to 38.9%). Six months' angiographic follow-up in 87 of 101 aneurysms showed incomplete occlusion in 14 (16%), and 12 (14%) of those had additional coiling. Mean packing of 19.4% of Nexus coils was significantly lower than 22.9% for GDC 10 and 29.7% for Trufill coils. Other clinical results were not significantly different. In this series, PGLA microfilament Nexus coils were safe to use with clinical results comparable with those of standard platinum coils. This study gives additional evidence of the lack of beneficial effect of PGLA addition to reduce the reopening rate of coiled intracranial aneurysms.

Statistical Error in Interpretation of Aneurysm Coil Results

To the Editor: We read with interest the recent report by Bendszus et al1 regarding the efficacy of new “bioactive” coils for cerebral aneurysm therapy. The authors note a “statistically significant” difference between outcomes in aneurysms treated with the Cerecyte coil and a matched pair cohort treated with bare platinum coils, with superior long-term occlusion rate for the Cerecyte group. We wish to call attention to a basic statistical error in their report, an error that lowered the calculated probability values to half of their true value, which might lead the reader to make an incorrect conclusion regarding the statistical superiority of Cerecyte coils. In the methods section, the authors state that 2-sided Fisher exact tests were performed “for comparison of the initial treatment …

Endovascular Treatment of Experimental Aneurysms with Use of Fibroblast Transfected with Replication-Deficient Adenovirus Containing Bone Morphogenetic Protein-13 Gene

Modified coils have failed to improve long-term recanalization of aneurysms. This study examined whether ex vivo transduction of replication-deficient adenovirus containing the bone morphogenetic protein-13 gene (Ad-BMP-13) in fibroblast allografts would improve angiographic results via increased collagen synthesis, compared with fibroblast-coated platinum coils (FBC) and bare platinum coils (PA). Aneurysms were embolized with Ad-BMP-13-coated coils (n = 20). Rabbits were sacrificed at 14 days and at 1, 3, and 6 months after implantation. Digital subtraction angiography (DSA) evaluated stability after embolization. Histologic specimens were examined with a qualitative grading system. Masson trichrome evaluated collagen deposition. Findings were compared with previously reported controls for PA and FBC in the same model and time points. The grading system showed a greater total score (P = .0002) in Ad-BMP-13 (6.8 +/- 1.6) and FBC (6.3 +/- 2.4) compared with PA (4.7 +/- 2.4). A group main effects test showed that aneurysm neck tissue coverage in Ad-BMP-13 (2.5 +/- 1.1) was higher (P = .0007) than both FBC (1.6 +/- 1.4) and PA (0.9 +/- 1.1). Ad-BMP-13 had more (P < .0001) collagen deposition than the FBC and PA. One- and 3-month Ad-BMP-13 collagen depositions increased (P < .05) over the FBC and PA. Finally, Ad-BMP-13 showed radiographic stability in 15 (75%) cases, coil compaction in 4 (20%) cases, and progressive occlusion in 1 (5%) case. There were no differences in angiographic results (P = .6522). The Ad-BMP-13-coated coils can improve neck coverage and dome fibrosis in the rabbit model, even in the absence of observed differences in angiographic outcome.

HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS Trial): Procedural Safety and Operator-Assessed Efficacy Results

Coated coils have been in clinical use for several years without robust evidence to determine their safety/efficacy. The HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS) addresses this deficiency for the HydroCoil embolic system. This article reports periprocedural safety/operator-assessed angiographic results from HELPS. Patients were randomized to the hydrogel coil or control arms by using concealed allocation with minimization matching groups. Any bare platinum coils were allowed in the control arm, and assist devices could be used as clinically required. Both recently ruptured and not recently ruptured/unruptured aneurysms were included. Analysis was on an intention-to-treat basis. Four hundred ninety-nine patients were recruited. Coiling was successful in 98.6%. Mean aneurysm size was 6.5 mm (26% were > or =10 mm), 53% were recently ruptured aneurysms, and an assist device was used in 46%. Seventy procedural adverse events were reported in hydrogel coils and 86 in control arms. The 3-month mortality rate was 3.6% in hydrogel coils and 2.0% in control arms; the difference was not significant (P = .6). There was a lower 2-month mortality rate in the HELPS subarachnoid hemorrhage cohort (4.1%) than would be anticipated from the International Subarachnoid Aneurysm Trial (7%). There was a trend toward increased adverse events when assist devices were used, which was substantial for stents deployed in recently ruptured aneurysms. Ninety-six percent of patients discharged were World Federation of Neurosurgeons grade 0-2 at discharge. No difference was found between arms in the operator assessment of angiographic occlusions (P = .3). These HELPS results reinforce coiling as an effective treatment for aneurysms, with an excellent technical success rate. Hydrogel coils can be used in a wide spectrum of aneurysms with a risk profile equivalent to that of bare platinum.

But Did You Use HydroCoil? Perianeurysmal Edema and Hydrocephalus with Bare Platinum Coils

Bioactive coils were developed to improve aneurysm packing and accelerate neointimal healing. Recent reports, however, have implicated these coils in the development of aseptic meningitis, perianeurysmal edema, and hydrocephalus. This report demonstrates that the same clinical phenomena can occur with the use of bare platinum coils.

MR angiographic evaluation is limited in intracranial aneurysms embolized with Nexus coils

Nexus coils are a type of bioactive coil used to embolize intracranial aneurysms. The purpose of this study was to test the feasibility of the noninvasive follow-up of aneurysms treated with Nexus coils by means of magnetic resonance angiography (MRA). Three-dimensional (3D) time-of-flight (TOF) MRA images of patients treated with Nexus coils (the Nexus coil group) or bare platinum coils (the control group) were compared for the severity and frequency of artifacts. The reviewers were unaware of the coil types used. In the Nexus coil group, 17 MRA examinations were performed in 14 patients harboring 15 aneurysms treated with Nexus coils using 3-T (n = 11) and 1.5-T (n = 6) MR units. The findings of these examinations were compared to those of 28 MRA studies conducted on 24 control patients (bare platinum coils). Conventional angiograms, maximum intensity projections, and source data of 3D-TOF MRA were reviewed in terms of residual flow within aneurysms and parent arterial patencies. The qualities of the MRA images were rated from grade 0 (no significant signal loss) to grade 2 (complete segmental signal loss of the parent artery). The normalized ratio, defined as the diameter of signal loss on MRA axial source images (in mm) divided by that of coil mass on plain radiographs (in mm), was calculated to compare the sizes of coil-related artifacts in the two groups. The quality of the MRA image for the Nexus coil group was significantly poorer than that for the control group (p < 0.0001) due to signal loss caused by the presence of artifacts in the former. In particular, the interpretation of aneurysmal status was impossible in all cases of coiled aneurysms due to segmental signal loss. The sizes of the MRA artifacts were also significantly larger in the Nexus coil group (normalized ratio 1.61 +/- 0.22 vs. 1.15 +/- 0.20; p < 0.0001). Follow-up evaluations by 3D-TOF MRA of aneurysms treated with Nexus coils are severely limited.

Single-Center Experience of Cerecyte Coils in the Treatment of Intracranial Aneurysms: Initial Experience and Early Follow-Up Results

Endovascular treatment of intracranial aneurysms using platinum coils is effective, but uncommonly aneurysms recur. New-generation coils, such as Cerecyte, aim to address this problem. This study examines the safety and efficacy of these coils in the treatment of a cohort of ruptured and unruptured aneurysms Sixty-seven patients with 68 aneurysms were included in the study. Of these, 51 were treated exclusively with the new polyglycolic acid (PGA)-containing coils, and 17 were treated with a combination of new PGA-containing and other coils. Initial and follow-up angiograms were graded according to the 3-point scale of occlusion. Follow-up angiography was available in 46 cases at 6 months. Based on occlusion grading at initial and follow-up angiography, aneurysms were classified into stable, improved, and worsened (recanalized) groups. Of the exclusive new-coil cohort, 36 cases (70.6%) were initially completely occluded (grade 1), 12 (23.5%) showed filling at the neck (grade 2), and 3 (5.9%) showed contrast within the neck and sac (grade 3). Analysis of the follow-up angiograms showed 24 (70.6%) had stable occlusion, 3 (8.8%) had improved occlusion, and 7 (20.6%) had worsening occlusion. Data for cases treated with new PGA-containing coils together with bare platinum coils were also analyzed separately. Intraprocedural adverse events were noted in 4 cases (7.8%), but there were no clinical sequelae. There were no rebleeds in the follow-up period. New PGA-containing coils show no excess in procedural and periprocedural complications over bare platinum coils, and the recanalization rate is comparable with bare platinum coils in the short term.

Endovascular Treatment of Intracranial Aneurysms with Matrix Detachable Coils: Midterm Anatomic Follow-Up from a Prospective Multicenter Registry

Polyglycolic/polylactic acid-covered platinum coils have been proposed to reduce the rate of aneurysm recanalization after endovascular treatment. A prospective and multicenter registry was conducted in France to evaluate the safety and short-term and midterm efficacy of Matrix coils. This analysis focused on anatomic midterm results. Two hundred thirty-six patients harboring 244 ruptured or unruptured aneurysms treated via endovascular approach by using Matrix coils were included in this registry. Treatment was totally or partially performed by using Matrix coils. Anatomic results were evaluated on postoperative and last-follow-up digital subtraction angiography (DSA) by using the Raymond scale. "Recanalization" was defined as worsening, and "progressive thrombosis" was defined as improvement on the Raymond scale. Anatomic midterm follow-up was obtained in 165 of 236 patients (70%) harboring 171 aneurysms (range, 6-27 months; mean, 14 +/- 4 months). At midterm follow-up angiography, 79 aneurysms were completely occluded (46.2%), 43 had a neck remnant (25.1%), and 49 had an aneurysm remnant (28.7%). Of 171 aneurysms, recanalization was observed in 44 patients (25.7%), including major recanalization in 18 patients (10.5%). Recanalization was more frequent if the embolized volume of aneurysm was </=25%. Progressive thrombosis was observed in 52 aneurysms (30%). No bleeding or rebleeding was observed during the period of follow-up. The efficacy of Matrix coils in preventing recanalization was not demonstrated in our series. In agreement with previous studies using bare platinum coils, volumic occlusion was an important feature for the prediction of aneurysm recanalization. A high percentage of progressive thrombosis in incompletely treated aneurysms was observed in our series, suggesting a biologic activity of Matrix coils.

Angiographic and histological comparison of canine bifurcation aneurysms treated with first generation matrix and standard GDC coils

It is claimed that bioactive coils induce accelerated and more durable aneurysm healing. Data supporting this claim are quite limited. Our purpose was to compare the angiographic and histological results obtained following treatment with different coil types. Bifurcation type aneurysms were surgically created in 24 dogs and treated using standard clinical techniques. Eight were treated with Guglielmi detachable coils (GDC), eight with first-generation Matrix coils, and eight with a combination of GDC and Matrix coils. The aneurysms were explanted and final angiographic evaluations performed 12 weeks after treatment. Angiographic and histological outcomes were documented. Increased coil compaction with aneurysm recurrence was found in aneurysms treated with first-generation Matrix coils as compared to standard GDC (P = 0.0001). In aneurysms treated with first-generation Matrix coils thrombus organization was better than in those treated with either standard GDC coils (P = 0.008) or with a combination of GDC and Matrix coils (P = 0.04). In aneurysms treated with first-generation Matrix coils there were no endothelialized vascular clefts within the coil mass, but they were seen in the majority of aneurysms treated with GDC or a combination of GDC and Matrix coils (P = 0.003). Aneurysms treated with first-generation Matrix coils showed the greatest degree of coil compaction and aneurysm recurrence on the final angiographic evaluation. Aneurysms treated with first-generation Matrix coils showed enhanced thrombus organization and absence of vascular clefts at the aneurysm neck that were markedly different from those treated with bare platinum coils or a combination of GDC and Matrix coils.