Guglielmi detachable coil embolization of cerebral aneurysms: 11 years' experience

Endovascular treatment of intracranial aneurysms with detachable coils: correlation between aneurysm volume, packing, and angiographic recurrence

BACKGROUND AND PURPOSE

The relationship between dense packing and incidence of angiographic recurrence after endovascular treatment of intracranial aneurysms has been shown but remains controversial. We retrospectively analyzed intracranial aneurysms treated with detachable coils to determine the relation between aneurysm volume, packing, and recurrence.

METHODS

We reviewed 221 aneurysms in 199 patients who underwent endovascular coiling using detachable coils from November 2009 to December 2011. Aneurysm volumes were determined using three-dimensional images obtained from rotational angiography. Aneurysm packing was defined as the ratio between the volume of coils inserted and the volume of aneurysm. At follow-up, angiographic results were dichotomized into presence or absence of recurrence. The relationship between aneurysm volume to fill, packing, and angiographic recurrence was determined by multivariable logistic regression.

RESULTS

Follow-up angiography (mean follow-up 8.8 months) revealed recurrence in 14.5% of the aneurysms studied in our series. Recurrent aneurysms had a mean packing of 15.1% while stable aneurysms (non-recurrent) had a mean packing of 23.7%. Multivariable logistic regression analysis showed that aneurysm volume and packing were significantly associated with angiographic recurrence. Large volume aneurysms (>600 mm(3)) were found to have a higher incidence of recurrence than those with small volumes (OR=30.49, p<0.001). Compared with those with high packing (≥20%), the less packed aneurysms (<20%) had a higher incidence of recurrence (OR=29.01, p=0.002). There was no significant difference between aneurysm location, clinical presentation, stent assistance, duration of follow-up, and recurrence.

CONCLUSIONS

Coiling large volume (>600 mm(3)) intracranial aneurysms are more likely to have a recurrence than small ones. High packing (≥20%) provides better protection against recurrence of the aneurysm.

Treatment of unruptured intracranial aneurysms with the pipeline embolization device

The pipeline embolization device (PED; ev3 Endovascular, Plymouth, MN, USA) is a flow-diverter used in the endovascular treatment of intracranial aneurysms, particularly those with unfavorable configurations. It causes progressive flow redirection leading to aneurysm thrombosis. This study aimed to present a systematic review of the published literature on the clinical outcomes of PED. A Medline search of the English language literature was performed using the keywords "intracranial aneurysms" and "pipeline embolization device" or "flow diverters". The inclusion criteria were: n>10 patients; unruptured aneurysms; documentation of complications; and at least 3 months of follow-up. A total of 13 studies, with 905 patients and 1043 aneurysms, were included. The mean age was 53.8 years, with women comprising 76.3% of patients. The mean aneurysm diameter was 11.1mm with 37% classed as large aneurysms and 10% classed as giant. The cumulative mortality rate was 2.3%. Seventeen patients had a stroke (1.9%), while 19 (2.0%) had a transient ischemic attack and 21 patients (2.3%) had an intracranial hemorrhage. The two outcome measures were the cumulative event rate (16.7%) and the 6 month aneurysm occlusion rate (79.7%). A funnel plot with study size plotted against the two outcome measures revealed publication bias. Data from recent studies suggest that complication and mortality rates associated with PED may be similar to other contemporary endovascular techniques, with a better 6 month aneurysm occlusion rate. More prospective clinical trials are warranted to further validate these results.

Early results of the Axium MicroFX for Endovascular Repair of IntraCranial Aneurysm (AMERICA) study: a multicenter prospective observational registry

BACKGROUND

Axium MicroFX coils contain polymer (polyglycolic/polylactic acid, PGLA) microfilaments designed to significantly impact intra-aneurysmal flow and to encourage aneurysm thrombosis. To provide preliminary evaluation of the safety and suggested efficacy of the MicroFX design, we performed a multicenter prospective single-arm trial, Axium MicroFX for Endovascular Repair of IntraCranial Aneurysm study (AMERICA).

METHODS

AMERICA is a prospective multicenter 100 aneurysm observational study evaluating the safety and efficacy of Axium MicroFX PGLA coils. Enrollment was started in April 2010 and completed in October 2012.

RESULTS

99 patients underwent treatment for 100 aneurysms at 13 centers. Mean age was 60.2 years, most were women (72%) and 18% of patients had previously undergone treatment for a separate aneurysm. 22% of patients underwent treatment after acute aneurysmal subarachnoid hemorrhage (SAH). Of these patients, all were Hunt and Hess grade 1-3. Pre-procedure modified Rankin score (mRS) was 0-2 in 92% of patients. The majority of aneurysms were anterior circulation (86%), with the most common aneurysm locations being the anterior communicating artery (23%) followed by the supraclinoid internal carotid artery and posterior communicating artery (18% each). The mean maximum diameter was 6.5 mm. Axium MicroFX coils could be placed in all but one treatment (99%). Raymond grade at conclusion of coiling was I (complete) in 52%, II (dog ear or residual neck) in 33% and III (residual aneurysm) in 15%. Discharge mRS was significantly worse in patients with SAH (62% mRS 0-2) compared with electively treated aneurysms (mRS 0-2 in 94%, p<001). Major events were uncommon (6% thromboembolic events, 3% intraoperative vessel or aneurysm rupture) and device-related adverse events (AE) were rare (2% of cases).

CONCLUSIONS

This prospective study of Axium MicroFX coils demonstrates excellent aneurysm occlusion rates. 52% of aneurysms were completely occluded post-procedure. Within the ruptured aneurysm group, post-procedure occlusion rates were 63.6%. Major AE rates were consistent with historical data.

Reappraisal of anatomic outcome scales of coiled intracranial aneurysms in the prediction of recanalization

Objective

Several scales are currently used to assess occlusion rates of coiled cerebral aneurysms. This study compared these scales as predictors of recanalization.

Methods

Clinical data of 827 patients harboring 901 aneurysms treated by coiling were retrospectively reviewed. Occlusion rates were assessed using angiographic grading scale (AGS), two-dimensional percent occlusion (2DPO), and volumetric packing density (vPD). Every scale had 3 categories. Followed patients were dichotomized into either presence or absence of recanalization. Kaplan-Meier analysis was conducted, and Cox proportional hazards analysis was performed to identify surviving probabilities of recanalization. Lastly, the predictive accuracies of three different scales were measured via Harrell's C index.

Results

The cumulative risk of recanalization was 7% at 12-month, 10% at 24-month, and 13% at 36-month of postembolization, and significantly higher for the second and third categories of every scale (p<0.001). Multivariate-adjusted hazard ratios (HRs) of the second and third categories as compared with the first category of AGS (HR : 3.95 and 4.15, p=0.004 and 0.001) and 2DPO (HR : 4.87 and 3.12, p<0.001 and 0.01) were similar. For vPD, there was no association between occlusion rates and recanalization. The validated and optimism-adjusted C-indices were 0.50 [confidence (CI) : -1.09-2.09], 0.47 (CI : -1.10-2.09) and 0.44 (CI : -1.10-2.08) for AGS, 2DPO, and vPD, respectively.

Conclusion

Total occlusion should be reasonably tried in coiling to maximize the benefit of the treatment. AGS may be the best to predict recanalization, whereas vPD should not be used alone.

Endovascular remodeling of tortuous cervical segments of the internal carotid artery that hinder the management of complex intracranial aneurysms

Introduction: Severe tortuosity of the cervical segment of the internal carotid artery (ICA) may hamper the navigation of intravascular devices for the management of complex intracranial aneurysms and even conventional techniques of ICA access can fail. In a group of selected cases, we analyzed the efficacy and safety of carotid stenting to straighten the Severe tortuosity for direct navigation of the devices. Methods: A case series of 16 patients harboring 18 intracranial aneurysms with a difficult endovascular approach because of a cervical ICA with Severe tortuosity were prospectively recruited at our institution from January 2005 to December 2007. When traditional means of correction could not surmount this obstacle, an overlap stenting with a distal-to-proximal technique was used to overcome the Severe tortuosity. The efficacy of the procedure was defined as the ability to reach and be able to treat the target lesion with a smooth navigation of the endovascular devices. Safety was documented by procedure-related complications. Results: The straightening of the vessel by the stent helped to overcome pitfalls, making possible an obstacle-free navigation of the endovascular devices to the target lesion in all cases. In 5 cases with severe or double kinking, a distal transfer of the curve beyond the stent was observed, without impact on the efficacy of the procedure. One case of periprocedural related technical complication occurred with a permanent stroke. During the follow-up period (22.7 ± 8.4 months) no case of stent-related stroke or severe hyperplasia was observed. Conclusions: Carotid stenting is an available option when a cervical ICA with Severe tortuosity hampers a smooth catheterization of the intracranial circulation, in carefully selected cases. It allows a relatively safe and free navigation and/or deployment of additional endovascular devices needed for the treatment of complex intracranial aneurysms.

Clinical and radiologic results of endovascular coil embolization for cerebral aneurysm in young patients

Purpose

This study is an overview of the clinical and radiologic outcomes of endovascular coil embolization for cerebral aneurysm in patients aged 40 years and younger.

Materials and Methods

Between January 2008 and June 2011, 218 aneurysms were treated using endovascular coil embolization and followed up with cerebral angiography at least six months later. Twenty-one aneurysms occurred in patients aged 40 years and younger, while 197 occurred in 179 patients older than 40 years. The clinical and radiologic results were retrospectively analyzed and compared between the two groups using the modified Rankin scale scores and the modified Raymond scale.

Results

Follow-up cerebral angiography revealed two (9.5%) major and two (9.5%) minor recanalized aneurysms in patients aged 40 years and younger, and six (3.0%) major and 35 (17.7%) minor recanalized aneurysms in patients older than 40 years. However, the differences between the groups were not statistically significant. The preoperative and postoperative mean modified Rankin scale scores at time for follow-up angiography were 1.14 and 0.19 respectively for patients aged 40 years and younger, and 1.30 and 0.30 respectively for patients older than 40 years.

Conclusion

The younger patients had clinically favorable outcomes with tolerable angiographic follow-up results. More regular and long-term imaging follow-up is required for younger patients due to their longer life expectancy.

Short-term outcome for saccular cerebral aneurysms treated with the Orbit Galaxy Detachable Coil System

Technological advancement within the field of neuroendovascular therapy may lead to safer and more robust treatment options for patients with lesions traditionally not favorable to coil occlusion. We analyze and report our outcomes with the Orbit Galaxy Detachable Coil System (DePuy Synthes, West Chester, PA, USA) for the treatment of anterior and posterior circulation saccular cerebral aneurysms. Patients treated with Orbit Galaxy coils for primary or recurrent saccular cerebral aneurysms from October 2010 to July 2012 were retrospectively reviewed using medical records, operative reports, and radiographs. Ninety-three patients, 69% unruptured and 31% ruptured, were treated with Orbit Galaxy coils for their anterior (80%) or posterior (20%) circulation saccular cerebral aneurysm. Primary treatment with Orbit Galaxy coils occurred in 84% of patients with an initial 100% occlusion rate of 65% while 16% had Galaxy coils placed into a "secondary" recurrent lesion. The overall incidence of recurrence was 26% with a mean interval of 7 months. Retreatment for recurrence was needed in 20 patients (22%). The mortality rate was 0%. A 2% incidence of rebleed was observed; each was after a secondary treatment. The morbidity of the treatment was low with 1% having a modified Rankin score greater than 3. Primary endovascular treatment of saccular cerebral aneurysms of the anterior and posterior circulation with the Orbit Galaxy Detachable Coil System is safe and effective in the short term.

Analysis of complications and recurrences of aneurysm coiling with special emphasis on the stent-assisted technique

BACKGROUND AND PURPOSE

Stent-assisted coiling has expanded the treatment of intracranial aneurysms. With the use of continuously compiled data, we reviewed the role and drawbacks of stent-assisted coiling.

MATERIALS AND METHODS

We compiled data from consecutive patients from 2003-2012 who underwent coiling, with or without stent assistance. Clinical and angiographic results were analyzed retrospectively.

RESULTS

Of 1815 saccular aneurysms in 1505 patients, 323 (17.8%) were treated with stents (299 procedures) and 1492 (82.2%) without stents (1400 procedures). Procedure-related complications occurred in 9.4% with stents versus 5.6% without stents (P = .016, relative risk 1.5; 95% CI, 1.1-2.7). Ischemic complications were more frequent in the stent group than in the no-stent group (7.0% versus 3.5%; P = .005; relative risk, 1.7; 95% CI 1.2-2.5), as were hemorrhagic complications (2.3% versus 1.9%, P = .64). Procedure-induced mortality occurred in 2.7% (8/299) with stents versus 1.1% (15/1400) without stents (P = .029; relative risk, 2.0; 95% CI, 1.1-3.5). Logistic regression analysis identified wide-neck aneurysms as the most significant independent predictor of complications. A total of 64.1% (207/323) of aneurysms treated with stents and 70.3% (1049/1492) treated without stents have been followed, disclosing angiographic recurrence in 15.5% (32/207) versus 35.5% (372/1049), respectively (P < .0001). Logistic regression analysis showed that the presence of a stent was the most important factor for the reduction of angiographic recurrence (P < .0001; relative risk, 2.3; 95% CI, 1.6-3.3).

CONCLUSIONS

The stent-assisted coiling technique is associated with a significant decrease in recurrences but a significant increase in complications. The treatment of wide-neck aneurysms remains hazardous.

Thromboembolic Events Associated with Electrolytic Detachment of Guglielmi Detachable Coils and Target Coils : Comparison with Use of Diffusion-Weighted MR Imaging

Objective

The purpose of this study was to retrospectively evaluate and compare the incidence of diffusion-weighted image (DWI) lesions between the Guglielmi detachable coil (GDC) and the Target coil for treating unruptured intracranial aneurysm.

Methods

From 2010 to 2011, consecutive 222 patients with an intracranial aneurysm underwent coil embolization. Inclusion criterias were : 1) unruptured intracranial aneurysm, 2) one or more GDC or Target coils used with or without other coils, 3) DWI examination within 24 hours after coiling, and 4) coiling performed without a balloon or stent.

Results

Ninety patients (92 cases) met the inclusion criteria. DWI lesions were detected in 55 (61.1%) of 90 patients. In the GDC group (n=44), DWI lesions were detected in 31 (70.5%). The average number of DWI lesions was 5.0±8.7 (mean±SD; range, 1-40) in aneurysm-related territory. In the Target coil group (n=48), DWI lesions were detected in 24 (50.0%). The number of DWI lesion was 2.1±5.4 (range, 1-32) in aneurysm-related territory. There was no significant correlation between a number of coils and DWI lesions. No significant differences were also observed in the number of DWI lesions in each group.

Conclusion

The GDC and Target coils, which have an electrolytic detachable system, showed no differences in the incidence of DWI lesion.

Differences in the angiographic evaluation of coiled cerebral aneurysms between a core laboratory reader and operators: results of the Cerecyte Coil Trial

BACKGROUND AND PURPOSE

Independent evaluation of angiographic images is becoming widely applied in the assessment of treatment outcomes of cerebral aneurysms. In the current study, we assessed the agreement between an independent core laboratory and the operators regarding angiographic appearance in a recent randomized, controlled trial.

MATERIALS AND METHODS

Data were derived from the Cerecyte Coil Trial. Angiographic images of each coiled aneurysm, taken immediately after embolization and at 5- to 7-month follow-up, were evaluated by the operator at the treating center and by an independent neuroradiologist at the core laboratory. For the purpose of this study, images were interpreted on a 3-point scale to provide uniformity for analysis; grade 1: complete occlusion, grade 2: neck remnant; and grade 3: sac filling. "Unfavorable angiographic appearance" was defined as grade 3 at follow-up or interval worsening of grade between the 2 time points.

RESULTS

The study included 434 aneurysms. Immediately after embolization, grade 3 was reported by operators in 39 (9%) compared with 52 (12%) by the core laboratory (P = .159). On follow-up, grade 3 was reported by operators in 44 (10%) compared with 81 (19%) by the core laboratory (P < .0001). Overall, operators noted unfavorable angiographic appearance in 78 (18%) compared with 134 (31%) by the core laboratory (P < .0001). At every time point, agreement between the core laboratory and the operators was slight.

CONCLUSIONS

Unfavorable angiographic appearance was noted almost twice as frequently by an independent core laboratory as compared with the operators. Planning of trials and interpretation of published studies should be done with careful attention to the mode of angiographic appearance interpretation.

Management of unruptured brain aneurysms: retrospective analysis of a single centre experience

Embolization is very effective in preventing bleeding of unruptured aneurysms with lower rates of mortality and morbidity than surgical treatment. Neurosurgery remains, however, a good alternative. This retrospective analysis examined data stored the digital database of Bellaria Hospital Radiology Department, evaluating patients, treatments and devices used as well as outcomes and complications. Therapy should be tailored to each individual case to offer each patient the best treatment. Out of 265 unruptured intracranial aneurysms detected, 182 were treated by embolization. 16 cases presented complications (12 only radiologically found); severe clinical consequences occurred in 3%: one ischaemia and five haemorrhages. Conservative treatment was adopted in 21 patients. Long-term follow-up is mandatory as aneurysms could increase their size and develop an irregular morphology in ten years' time. Endovascular embolization is a very effective treatment with positive outcomes in the majority of cases and a percentage of retreatments of 8%. In order to increase the number of successful cases, a multidisciplinary cooperation with neurosurgeons is strongly recommended.

Endovascular Enterprise stent-assisted coil embolization for wide-necked unruptured intracranial aneurysms

We evaluated the safety and efficacy of stent-assisted coil embolization for wide-necked unruptured intracranial aneurysms (UIA) based on the results observed in consecutive patients in a single center. This study included 116 patients (29 men, 87 women; mean age, 55.4 years) with 121 UIA which were treated by stent-assisted coil embolization from November 2008 to December 2010. A single stent type (Enterprise; Codman & Shurtleff, Raynham, MA, USA) was used. The clinical and radiological results were evaluated. Embolization was successful without complications in 94% of patients. Six patients had procedure-related thromboembolic events, resulting in neurologic symptoms in four patients, and transient angiographically-visible asymptomatic thromboembolism in two patients. Angiographic aneurysm occlusion was complete in 30.5% of patients, with a small neck remnant in 49.5%, and residual contrast filling in 19.8%. Dual antiplatelet agents were given for at least for 6 months. Thromboembolic stroke developed in three patients during follow-up; all occurred after discontinuation of clopidogrel and/or aspirin. Magnetic resonance angiography (MRA) follow-up was performed for at least 6 months. The mean follow-up was 13.4 months (range, 6-34 months). Eight patients (6.6%) demonstrated recanalization on MRA. Recoiling was performed in one patient (0.8%). The other seven patients with minor recanalization were conservatively followed. Enterprise stent-assisted coil embolization for the treatment of UIA appears to be effective and safe. Future studies including controlled prospective trials and careful follow-up are required to assess its indications and efficacy on a long term basis.

Does stent implantation improve the result of repeat embolization in recanalized aneurysms?

BACKGROUND

Although endovascular technique and related devices continue to improve, recanalization of embolized aneurysm remains a pitfall of this approach. The problem of how to treat the recanalized aneurysm needs to be addressed.

OBJECTIVE

To determine the outcomes of patients undergoing repeat embolization for recanalized intracranial aneurysms and to evaluate the impact of stent implantation on subsequent recanalization.

METHODS

Between September 2001 and September 2011, we performed endovascular retreatment in 162 patients with a total of 197 recanalized intracranial aneurysms. Stent implantation was performed in 68 aneurysms during the retreatment. Clinical and morphological outcomes were assessed at 6 months or more after repeat embolization.

RESULTS

Procedure-related complications, including asymptomatic thromboembolism, occurred with 15 aneurysms (7.6%) without permanent neurological sequelae. Follow-up imaging of 172 aneurysms documented stable occlusion in 96 of the lesions (55.8%), minor recanalization in 17 (9.9%), and major recanalization in 59 (34.3%) during the mean follow-up period of 26.0 ± 18.0 months. In multiple logistic regression analysis, stent implantation was shown to reduce the major recanalization rate at 6 months after retreatment (odds ratio: 0.161; 95% confidence interval:, 0.038-0.670; P = .012) and thereafter (odds ratio: 0.226; 95% confidence interval: 0.088-0.581; P = .002).

CONCLUSION

Stent implantation, as well as compact coil packing, at the time of repeat embolization seems beneficial in reducing rates of further recanalization.

Long-term outcomes of coil packing for visceral aneurysms: correlation between packing density and incidence of coil compaction or recanalization

PURPOSE

To evaluate the correlation between packing density and the incidence of coil compaction or recanalization of visceral artery aneurysms (VAAs) after coil packing.

MATERIALS AND METHODS

Between July 2004 and April 2012, coil packing was performed for 46 true visceral aneurysms (16 splenic, 11 pancreaticoduodenal, eight renal, six hepatic, three superior mesenteric, one right gastric, and one gastroepiploic) in 42 patients. The size and volume of the aneurysm, packing density, and the incidences of compaction and recanalization were evaluated retrospectively.

RESULTS

The mean follow-up period was 37 months ± 8 (range, 11-80 mo). The mean packing density was 19% ± 8 (range, 5%-42%), mean aneurysm size was 19 mm ± 8 (range, 5-40 mm), and mean volume was 4,108 mm(3) ± 5,435 (range, 72-26,235 mm(3)). Compaction and recanalization occurred in two (4%) and 12 aneurysms (26%), respectively. The mean packing density was significantly lower in aneurysms with compaction or recanalization than in unaffected aneurysms (12% vs 22%; P = .00014). There was a significant difference in mean packing density between small (< 20 mm; 22%) and large (≥ 20 mm) aneurysms (15%; P = .0045). The mean size and volume were significantly larger for coil-compacted or recanalized aneurysms than for unaffected aneurysms (P < .05). In aneurysms with a packing density of at least 24%, no compaction or recanalization occurred.

CONCLUSIONS

Coil compaction or recanalization after coil packing for VAAs more often occurs after insufficient embolization with low packing density and in patients with large aneurysms.

Endovascular treatment of intracranial aneurysms with flow-diverter stents: preliminary single-centre experience

PURPOSE

This paper reports our preliminary experience with the endovascular treatment of intracranial aneurysms using flow-diverter stents (FDs) and compares it with the literature data.

MATERIALS AND METHODS

From May 2009 to April 2012, 28 patients (6 men and 22 women; mean age, 54 years) with a total of 35 aneurysms were treated with FDs. We evaluated postprocedural technical success and long-term efficacy, with follow-up examinations performed at 3-7 days [computed tomography (CT)/magnetic resonance (MR) angiography] and at 3, 6 and 12 months (digital subtraction angiography, DSA). A total of 43 FDs were placed, 36 Pipeline and 7 Silk.

RESULTS

A total of 30 procedures were performed (two patients were treated twice). Technical success was 96.6%, with one case of postprocedural death; the aneurysm exclusion rate at 3, 6 and 12 months was 60%, 73% and 89%, respectively. There was no case of acute stent thrombosis, and only two cases of nonsignificant stenosis. All covered side branches were patent, except one case of steno-occlusion of the ophthalmic artery.

CONCLUSIONS

Our results are consistent with the literature and demonstrate the effectiveness and safety of FDs in selected cases of cerebral aneurysm (wide neck, fusiform, blister-like).

Incorporation of extruded coils into the third nerve in association with third nerve palsy

The extrusion of the coil complex outside of the aneurysmal dome is thought to be an important mechanism by which the aneurysm neck and fundus recanalize, but the migration of the coil loops and their incorporation inside vital nervous structures has not been clearly described. We reviewed the medical literature on coil extrusion and migration and report a rare case of third nerve palsy due to direct damage caused by coil loop migration that resolved after surgery. A 25-year-old woman presented with subarachnoid hemorrhage and painful left third nerve palsy. The angiogram revealed a supraclinoid internal carotid aneurysm incorporating the origin of the left posterior communicating artery. Her aneurysm was coiled. The 8 month follow-up angiogram revealed a major recurrence of her aneurysm. It was decided to surgically clip the aneurysm. At surgery, coil loops were found in the subarachnoid space and embedded into the third nerve. At 1 month follow-up she had recovered well, and only had very subtle diplopia upon fatigue. Coil extrusion is a fairly common phenomenon that should be suspected in instances of major aneurysmal recurrence. Surgical treatment is recommended, and special care should be taken when mobilizing the extruded coil mass.

In vitro characteristics of a gelling PEGDA-QT polymer system with model drug release for cerebral aneurysm embolization

A liquid-to-solid gelling polymer system, such as the poly(ethylene glycol) diacrylate-pentaerythritol tetrakis (3-mercaptopropionate) (PEGDA-QT) system, can fill cerebral aneurysms more completely than current embolization materials, reducing the likelihood of aneurysm recurrence. PEGDA-QT gels were formulated using PEGDA of different molecular weights (PEGDA575 and PEGDA700 ), and their characteristics were examined in vitro. Experiments examined gel time, mass change, crosslink integrity, cytotoxicity, and protein release capabilities. In general, PEGDA575 -QT gels were more hydrophobic, requiring an initiating solution with a higher pH (pH 9.5) to achieve a gel time comparable to PEGDA700 -QT gels, which used an initiating solution at pH 9.19. The mass change and crosslink integrity of gels were analyzed over time after gels were submerged in 150 mM phosphate buffered saline. After 380 days, PEGDA575 -QT gels achieved a maximum mass increase of 72% due to water uptake, while PEGDA700 -QT gels doubled their initial mass (100% increase) by 165 days. Compression tests showed that PEGDA700 -QT gels hydrolyzed more quickly than PEGDA575 -QT gels. Cytotoxicity assays showed that in general, PEGDA575 -QT negatively affected cell growth, while PEGDA700 -QT gels promoted cell viability. Sustained, controlled release of lysozyme, a 14.3 kDa protein, was achieved over an 8-week period when loaded into PEGDA700 -QT gels, but PEGDA575 -QT gels did not show sustained release. These studies show that although they are similar in composition, these PEGDA-QT gel formulations behave considerably differently. Although PEGDA700 -QT gels swell more and degrade faster than PEGDA575 -QT gels, their cytocompatibility and protein release characteristics may prove to be more beneficial for in vivo aneurysm treatment. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.

Visual outcomes for surgical treatment of large and giant carotid ophthalmic segment aneurysms: a case series utilizing retrograde suction decompression (the “Dallas technique”)

Object

The authors report their results in a series of large or giant carotid ophthalmic segment aneurysms clipped using retrograde suction decompression.

Methods

A retrospective review of clinical data and treatment summaries was performed for 18 patients with large or giant carotid artery ophthalmic segment aneurysms managed operatively via retrograde suction decompression. Visual outcomes, Glasgow Outcome Scale (GOS) scores, and operative complications were determined. Postoperative angiography was assessed.

Results

During a 17-year period, 18 patients underwent surgery performed using retrograde suction decompression. The mean aneurysm size was 26 mm. Three patients presented with subarachnoid hemorrhage. Fourteen of 18 patients presented with visual symptoms. Eleven (79%) of these 14 patients experienced visual improvement and the remaining 3 (21%) experienced worsened vision after surgery. Of 3 patients without visual symptoms and a complete visual examination before and after surgery, 1 had visual worsening postoperatively. One aneurysm required trapping and bypass, and all others could be clipped. Postoperative angiography demonstrated complete occlusion in 9 of 17 clipped aneurysms and neck remnants in the other 8 clipped aneurysms. One (5.5%) of 18 patients experienced a stroke. Eighteen patients had a GOS score of 5 (good outcome), and 1 patient had a GOS score of 4 (moderately disabled). There were no deaths. There was no morbidity related to the second incision or decompression procedure. Prolonged improvement did occur, and even in some cases of visual worsening in 1 eye, the overall vision did improve enough to allow driving.

Conclusions

Retrograde suction decompression greatly facilitates surgical clipping for large and giant aneurysms of the ophthalmic segment. Visual preservation and improvement occur in the majority of these cases and is an important outcome measure. Developing endovascular technology must show equivalence or superiority to surgery for this specific outcome.

The next generation HydroCoil: initial clinical experience with the HydroFill embolic coil

Background

Complete packing of intracranial aneurysms has demonstrated a significant decrease in aneurysm recurrence rates with increased volumetric filling. The HydroCoil Embolization System (HES) was developed to increase volumetric filling within the aneurysm sac to maintain long term occlusion. To further enhance ease of HES deployment, a new next generation embolic coil, the HydroFill coil, was developed.

Objective

To report the first clinical experience with the HydroFill coil, focusing on safety and effectiveness, with immediate and long term follow-up on cases performed at a single institution by a single operator.

Methods

Retrospective angiographic and clinical analysis was performed on a non-randomized single arm registry of the first consecutive 11 patients with 14 intracranial saccular aneurysms treated during a 9 month period.

Results

The immediate angiographic occlusion rate according to the Raymond scale was 100%. Overall packing density of all coils used was 13–135% (mean 64%). The immediate complication rate was 9% (1/11 patients), secondary to a parent vessel occlusion which resolved after intravenous administration of eptifibatide (Integrilin) without neurological sequelae. The angiographic/MR angiography follow-up period for this series was 13–30 months, with an overall complete occlusion rate of 86% (12/14 aneurysms). 2/14 aneurysms (14%) converted from complete occlusion to filling of small neck remnants. Of the two, one (7%) was a cavernous aneurysm that was retreated.

Conclusions

Although this initial case series is small, this study demonstrates safe deployment of the HydroFill coil in ruptured and unruptured aneurysms without major complications, and with a high rate of occlusion on long term follow-up.

In vivo embolization of lateral wall aneurysms in canines using the liquid-to-solid gelling PPODA-QT polymer system: 6-month pilot study

OBJECT

Over the past 20 years, endovascular embolization has become the preferred method of treating cerebral aneurysms. While there are many embolic devices on the market, none is ideal. In this study the authors investigated the use of a liquid-to-solid gelling polymer system-that is, poly(propylene glycol) diacrylate and pentaerythritol tetrakis (3-mercaptopropionate) (PPODA-QT)-to embolize in vivo aneurysms over a 6-month period.

METHODS

Experimental aneurysms were created in the carotid arteries of 9 canines. Aneurysms were embolized with the polymer only (PPODA-QT, 3 dogs), filled with PPODA-QT after placement of a "framing" platinum coil (coil+PPODA-QT, 3 dogs), or packed with platinum coils (coils only, 3 dogs). Aneurysm occlusion was angiographically monitored immediately and 6 months after embolization. After 6 months, the ostial regions of explanted aneurysms were assessed macroscopically and histologically.

RESULTS

All aneurysms showed 100% angiographic occlusion at 6 months, but turbulent blood flow was observed in 1 coils-only sample. Ostial regions of explanted coils-only aneurysms showed neointimal tissue surrounding individual coils but no continuous tissue layer over the aneurysm neck. All PPODA-QT aneurysms displayed smooth ostial surfaces, but 2 of 3 coil+PPODA-QT aneurysms showed polymer (unassociated with the coil) protruding into the vessel lumen, contributing to rough ostial surfaces. Neointimal tissue was present in PPODA-QT and coil+PPODA-QT aneurysms and covered smooth ostial surfaces more completely than in coils-only aneurysms.

CONCLUSIONS

This study compared neointimal tissue overgrowth in the ostium of experimental aneurysms embolized with PPODA-QT, PPODA-QT plus a framing coil, or coils alone. The coils-only and coil+PPODA-QT groups showed rough and discontinuous ostial surfaces, which hindered neointimal tissue coverage. The PPODA-QT aneurysms consistently produced smooth ostial surfaces that facilitated more complete neointimal tissue coverage over aneurysm necks.

Use of stent-assisted coil embolization for the treatment of wide-necked aneurysms: A systematic review

Background:

The use of stent-assisted coiling (SAC) has been shown to be a treatment option for complex aneurysms. We reviewed systematically the immediate and mid-term angiographic results following treatment of wide-necked aneurysms with self-expanding stents and coils, as well as the peri- and postprocedural rate of complications.

Methods:

A computerized database search was conducted from 01/2000 to 04/2011 using appropriate indexed terms on Pubmed. Inclusion criteria were: (1) homogeneous populations of ≥10 patients with wide-necked aneurysms; (2) use of a self-expandable neurovascular stent and coils for aneurysm treatment; (3) immediate and follow-up angiographic results; and (4) periprocedural and delayed thrombotic complications.

Results:

Seventeen studies were included, containing retrospectively collected data on 656 patients/702 aneurysms. The target aneurysm was located on the anterior circulation in 78.4% of patients. The immediate rate of complete occlusion was 46.3%, (19.3-98.1%). The intra- and postprocedural rate of intrastent thrombosis or thromboembolic event was 4.6% and 4.3%, respectively. Complete occlusion was documented in 71.9% at last angiographic follow-up. The rate of recanalization was 13.2% of aneurysms (0-28.8%). Delayed in-stent stenosis occurred in 5.3% cases (0-20.6%).

Conclusion:

SAC has been considered a treatment option for selected wide-necked aneurysms in some institutions. The use of intracranial stents should take into consideration the risk of ischemic complications, recanalization, delayed in-stent stenosis; and the currently unknown lifetime risks for stenosis, vascular injury, device failure, and aneurysm recurrence related to intracranial stenting. There is an evident need for a prospective multicenter registry for all treated patients with SAC.

Double stent-assisted coil embolization treatment for bifurcation aneurysms: immediate treatment results and long-term angiographic outcome

BACKGROUND AND PURPOSE

The goal of endovascular treatment of cerebral bifurcation aneurysms is to achieve safe coiling of the sac along with preserving patency of the diverging branches. Our purpose was evaluate procedural safety and efficacy as well as the long-term durability of endovascular treatment of bifurcation aneurysms with double stent-assisted coiling.

MATERIALS AND METHODS

One hundred ninety-one consecutive patients with bifurcation aneurysms were included in this series. Technical failure occurred in 3 aneurysms (1.5%); 188 patients with 193 aneurysms treated with double stent-assisted coiling were retrospectively evaluated; 113 aneurysms were located at middle cerebral artery bifurcation, 42 at the anterior communicating artery, 22 at the basilar artery bifurcation, and the remaining 16 at the internal carotid artery bifurcation; 132 were small (<10 mm), 56 were large (10-25 mm), and 5 were giant (>25 mm).

RESULTS

The technical success rate of double-stent application was 98.5% (193 aneurysms). In total, there were 5 procedural complications with an associated rate of 2.7%, one of which led to death (0.5%). Delayed ischemic stroke occurred in 2 patients (1.1%). Overall, permanent morbidity occurred in 2 patients, with associated rate of 1.1%. Follow-up was obtained in 186 aneurysms (96.4%), and recanalization occurred in 4 aneurysms (2.2%). In subgroup analysis, the recanalization rate was 3.8% for large aneurysms and 40% for giant aneurysms. No recanalization occurred in small aneurysms.

CONCLUSIONS

Dual stent-assisted coiling of cerebral aneurysms is a feasible and safe procedure. It may offer a curative solution with long-term durability for treatment of wide-neck small and large aneurysms.

Flow diverter effect on cerebral aneurysm hemodynamics: an in vitro comparison of telescoping stents and the Pipeline

INTRODUCTION

Flow diverting devices and stents can be used to treat cerebral aneurysms too difficult to treat with coiling or craniotomy and clipping. However, the hemodynamic effects of these devices have not been studied in depth. The objective of this study was to quantify and understand the fluid dynamic changes that occur within bifurcating aneurysms when treated with different devices and configurations.

METHODS

Two physical models of bifurcating cerebral aneurysms were constructed: an idealized model and a patient-specific model. The models were treated with four device configurations: a single low-porosity Pipeline embolization device (PED) and one, two, and three high-porosity Enterprise stents deployed in a telescoping fashion. Particle image velocimetry was used to measure the fluid dynamics within the aneurysms; pressure was measured within the patient-specific model.

RESULTS

The PED resulted in the greatest reductions in fluid dynamic activity within the aneurysm for both models. However, a configuration of three telescoping stents reduced the fluid dynamic activity within the aneurysm similarly to the PED treatment. Pressure within the patient-specific aneurysm did not show significant changes among the treatment configurations; however, the pressure difference across the untreated vessel side of the model was greatest with the PED.

CONCLUSION

Treatment with stents and a flow diverter led to reductions in aneurysmal fluid dynamic activity for both idealized and patient-specific models. While the PED resulted in the greatest flow reductions, telescoping high-porosity stents performed similarly and may represent a viable treatment alternative in situations where the use of a PED is not an option.

Safety and efficacy of endovascular treatment of basilar tip aneurysms by coiling with and without stent assistance: a review of 235 cases

BACKGROUND

Endovascular therapy is now the preferred treatment option for basilar tip aneurysms (BTAs).

OBJECTIVE

To compare the safety and efficacy of common endovascular techniques in the treatment of BTAs.

METHODS

A retrospective review was conducted of 235 patients with BTAs treated with endovascular means in our institution between 2004 and 2011. Categorization was based on the presence and type of stent assistance (none, single, and Y stenting). The rates of perioperative complications, recanalization, rehemorrhage, and retreatment were analyzed.

RESULTS

A total of 147 patients were treated with coil embolization and 88 patients with stent-assisted coiling (72 single stents, 16 Y stents). Thromboembolic complications occurred in 6.8% of patients in both groups. There was no associated mortality. Angiographic follow-up (mean, 23.5 months) was available in 172 patients (77.1%). Stented patients had significantly lower recanalization (17.2% vs 38.9%; P=.003) and retreatment (7.8% vs 27.8%; P=.002) rates compared with nonstented patients. Four rehemorrhages (2.7%) occurred in the coiled group, whereas none were noted in the stented group (P=.3). In paired comparisons, lower recanalization (8.3% vs 19.2%; P=.21) and retreatment (0% vs 9.6%; P=.19) rates were seen in the Y-stent group compared with the single-stent group. Thromboembolic complications occurred in 6.9% and 6.2% of patients in the single-stent and Y-stent groups, respectively (P=.91). In multivariate analysis, larger aneurysms, nonstented aneurysms, incomplete initial occlusion, and subarachnoid hemorrhage were predictors of aneurysm recanalization.

CONCLUSION

Stent-assisted coiling has significantly lower recurrence, retreatment, and rehemorrhage rates than coiling alone for the treatment of BTAs. Y stenting has the highest efficacy with low complication rates.

Pipeline for uncoilable or failed aneurysms: results from a multicenter clinical trial

PURPOSE

To evaluate the safety and effectiveness of the Pipeline Embolization Device (PED; ev3/Covidien, Irvine, Calif) in the treatment of complex intracranial aneurysms.

MATERIALS AND METHODS

The Pipeline for Uncoilable or Failed Aneurysms is a multicenter, prospective, interventional, single-arm trial of PED for the treatment of uncoilable or failed aneurysms of the internal carotid artery. Institutional review board approval of the HIPAA-compliant study protocol was obtained from each center. After providing informed consent, 108 patients with recently unruptured large and giant wide-necked aneurysms were enrolled in the study. The primary effectiveness endpoint was angiographic evaluation that demonstrated complete aneurysm occlusion and absence of major stenosis at 180 days. The primary safety endpoint was occurrence of major ipsilateral stroke or neurologic death at 180 days.

RESULTS

PED placement was technically successful in 107 of 108 patients (99.1%). Mean aneurysm size was 18.2 mm; 22 aneurysms (20.4%) were giant (>25 mm). Of the 106 aneurysms, 78 met the study's primary effectiveness endpoint (73.6%; 95% posterior probability interval: 64.4%-81.0%). Six of the 107 patients in the safety cohort experienced a major ipsilateral stroke or neurologic death (5.6%; 95% posterior probability interval: 2.6%-11.7%).

CONCLUSION

PED offers a reasonably safe and effective treatment of large or giant intracranial internal carotid artery aneurysms, demonstrated by high rates of complete aneurysm occlusion and low rates of adverse neurologic events; even in aneurysms failing previous alternative treatments.

Endovascular management of distal ACA aneurysms: single-institution clinical experience in 22 consecutive patients and literature review

BACKGROUND AND PURPOSE

Distal ACA aneurysms remain difficult to treat with endovascular therapy, but improved technology and experience allows for the treatment of some of these aneurysms with excellent results. The purpose of this study was to assess the status of endovascular treatment of distal ACA aneurysms by comparing our results with recent endovascular and microsurgical series of distal ACA aneurysms.

MATERIALS AND METHODS

Between 2000 and 2008, a total of 22 consecutive patients (14 women; mean age, 58.4 years) with distal ACA aneurysms underwent coil placement at Barrow Neurological Institute. Clinical presentations, radiographic findings, endovascular management, and outcomes were reviewed retrospectively.

RESULTS

Of the 22 patients, 13 (59%) presented with subarachnoid hemorrhage. Six patients were HH grade I or II, 1 was grade III, 5 were grade IV, and 1 was grade V. Frontal lobe hematomas occurred in 5 patients with ruptured aneurysms. The mean aneurysm size was 7.5 mm (range, 2.8-25 mm); 55% were smaller than 7 mm. Twelve aneurysms (55%) arose from the origin of the callosomarginal artery (55%). Complete occlusion was achieved in 50% of the cases and near-complete occlusion in 45%. The few periprocedural complications included 1 retroperitoneal hematoma and 1 intraoperative rupture. Four patients had thromboembolic events adequately treated intraprocedurally with abciximab. No deaths occurred in the patients treated.

CONCLUSIONS

The characteristics of the patients and aneurysms treated in our series were comparable to previous reports of endovascular treatment of ACA aneurysms with respect to rupture status. Periprocedural morbidity and mortality rates in our series fared well compared with previous reports, as did our combined rate of complete or near-complete occlusions. Recent advances in endovascular devices and techniques have improved outcomes of distal ACA aneurysms.

[Aneurysmal subarachnoid hemorrhage]

Acute subarachnoid hemorrhage (SAH) is a severe and acute life-threatening cerebrovascular disease. Approximately 80% of all acute non-traumatic SAHs are the result of a ruptured cerebrovascular aneurysm. Despite advances in diagnosis and treatment a high morbidity and mortality still exists. Apart from the primary cerebral damage there are also secondary complications, such as vasospasm, rebleeding, hydrocephalus, cerebral edema or hydrocephalus. For an appropriate therapy an understanding of the extensive pathophysiology, the options in diagnostics and therapy and the complications of the disease are essential. Anesthesiologists are decisively involved in the therapy of the primary and secondary damages and subsequently in the outcome as well. This article provides an overview of the perioperative and intensive care management of patients with SAH.

Review of 2 decades of aneurysm-recurrence literature, part 1: reducing recurrence after endovascular coiling

SUMMARY

Angiographic recurrence following endovascular therapy is an indirect measure of the potential for hemorrhage. Because patients and physicians consider recurrence to be a suboptimal outcome with some chance of future hemorrhage, much effort has been expended to reduce the incidence of recurrence. The literature regarding aneurysm recurrence following endovascular therapy, spanning 2 decades, is extensive. We will review and summarize the effort to reduce recurrence following endovascular treatment of cerebral aneurysms.

Aneurysm embolization grade: a predictive tool for aneurysm recurrence after coil embolization

BACKGROUND

Coil embolization has gained importance in the management of intracranial aneurysms over the past decade. However, the recurrence risk after embolization mandates closer follow-up than surgical clip ligation. Currently, there is no reliable system for predicting aneurysm sac thrombosis. An aneurysm embolization grade (AEG) reported previously by the senior author (EMD) has been proposed as a tool for predicting the durability of aneurysm occlusion based on hemodynamic characteristics. Here, we present our internal validity results.

METHODS

AEG and Raymond-Roy Occlusion Classification (RROC) scores were prospectively assigned to all aneurysms coiled from June 2008 to June 2011. The prospectively assigned AEG and RROC scores from the cerebral angiograms were collected for data analysis and validity assessment of the AEG system. 110 consecutive patients who had aneurysm coil embolization were included in this study.

RESULTS

The post-coiling AEG significantly predicted follow-up angiographic filling characteristics. Pairwise comparisons revealed that the follow-up AEG for those initially scored 'A' (complete obliteration) was significantly better than the contrast-flow groups. Significant differences were also noted between contrast-stasis and contrast-flow groups. A pairwise comparison between RROC scores demonstrated that only the RROC Type 1 could be used to predict follow-up occlusion durability. Stent placement in wide-neck aneurysms had no effect on initial AEG, RROC, or long-term occlusion durability. Packing density significantly predicted initial AEG and RROC, but had no effect on long-term occlusion.

CONCLUSIONS

The AEG system is uniquely based on angiographic filling characteristics of the aneurysm, and this study demonstrated its high predictive value for determining aneurysm sac thrombosis. Assigning an AEG to the aneurysm can guide the neurointerventionalist in discussions with the patient regarding the probability of aneurysm recurrence and potential need for retreatment.

Endovascular treatment of cerebral aneurysms in relation to their parent artery wall: a single center study

We report our two-year experience in the endovascular treatment of brain aneurysms in relation to their parent artery wall. We prospectively recorded patients with intracranial aneurysms (107 ruptured - 38 unruptured) treated with coiling during a two-year period: 145 patients, 94 females and 51 males - mean age 56 years. The aneurysms were divided into side-wall (A) and bifurcation (B) groups. A total occlusion rate was noted in post-embolization angiograms in 101 aneurysms (70%) with a morbidity of 4%. No angiographic recurrence arose in the six-month follow-up. The two groups had a similar total occlusion rate (68.31% and 71.8% respectively), while the complication rate was 3% in group A and 4.7% in group B. Significant differences between the two groups were noted in the number of assisted coiling cases: 28 out of 60 cases (46.7%) in group A - 14 out of 85 cases (16.5%) in group B. Further statistical analysis showed strong dependencies for the type of endovascular procedure between the ruptured and unruptured aneurysms in both groups (p 0.000<0.05), but no dependencies between the aneurysm occlusion rate and the ruptured or non-ruptured aneurysms, or between the occlusion rate and the type of endovascular procedure (p 0.552>0.05 and 0.071>0.05 respectively). In conclusion, the anatomic relation of the aneurysm sac with the wall of the parent artery is important, as significant differences in endovascular practice, devices and techniques were noted between side-wall and bifurcation aneurysms.

The retreatment: indications, technique and results

Durability of endovascular treatment of intracranial aneurysms has always been an issue and a very strong point of criticism. Although studies on long-term results have made it clear that endovascular treatment safe and effective they, nonetheless showed retreatment after endovascular treatment is nearly 5-10 times more frequent than surgical clipping. Risk factors predisposing high probability of retreatment are aneurysm with dissecting nature, incomplete coiling, sac size larger than 10mm and localization at the bifurcations such as basilar tip. The indications for retreatment after endovascular treatment are not clear yet, although certain morphologic criteria can be used. Retreatment appears not to negate the initial advantage of endovascular treatment over surgical treatment and can be performed very small morbi-mortality numbers.

Safety and efficacy of neuroform for treatment of intracranial aneurysms: a prospective, consecutive, French multicentric study

BACKGROUND AND PURPOSE

Endovascular embolization of wide-neck intracranial aneurysms can be technically challenging, especially when the anatomy is complex. Stent reconstruction of the parent artery is commonly used to treat wide-neck and bifurcated aneurysms. The main objective of this study was to investigate the periprocedural and midterm morbidity and mortality results of this procedure.

MATERIALS AND METHODS

SENAT is a consecutive, prospective, multicentric study. Patients with unruptured cerebral aneurysms who underwent endovascular treatment with the Neuroform stent system were recruited and recorded. Technical outcomes and complications were also assessed. The midterm anatomic results were re-evaluated at 12-18 months.

RESULTS

A total of 113 stents were used to treat the 107 aneurysms in 107 patients. The mean width of the aneurysm sac was 6.2 mm, and the mean diameter of aneurysm neck was 4.5 mm. The complete occlusion rate postprocedure was 66.4%. The rate of progressive occlusion at 12-18 months was 14%, and the rate of recurrence was 9.7%. The rate of subsequent treatment was 4%. The thromboembolic rate in the periprocedural period was 3.7%, and the rate of delayed TE events was 3%. Overall, the mortality rate at 12-18 months was 1%, and the permanent morbidity rate was 1%.

CONCLUSIONS

Stent-assisted coiling with the Neuroform stent system provides a high level of occlusion with low rates of subsequent treatment despite a predominant population of patients with wide-neck aneurysms. Morbidity and thromboembolic rates were comparable to studies investigating stand-alone coiling.

Microsurgical clipping of previously coiled intracranial aneurysms

OBJECTIVE

Endovascular coiling techniques for the treatment of intracranial aneurysms have rapidly developed as an alternative option to surgical clipping. A distinct problem after endovascular coiling is the management of a residual aneurysm neck due to incomplete filling, compaction of coils or regrowth of the aneurysm. Treatment options in this situation include surgical clipping, re-coiling, stent implantation or observation.

METHODS

From June 2006 to August 2011, 15 patients underwent surgical clipping of residual or recurrent aneurysms after previous endovascular treatment. The mean age of the patients was 50.6 years (range, 27-85 years). The mean interval between coiling and clipping was 76.5 weeks (range, 0-288 weeks).

RESULTS

Thirteen patients revealed a regrowth of coiled aneurysms, and in 5 patients compaction of coils was present. Coil extrusion was observed in 9 patients intraoperatively. In case of coil obstruction at the aneurysmal neck during surgery, coils were partially or completely removed. In all cases complete occlusion of the aneurysms was surgically achieved.

CONCLUSION

Coiled aneuryms with incomplete occlusion, coil compaction or regrowth of the aneurysmal neck can be successfully treated with microsurgical clipping. Coil extrusion was more often observed intraoperatively than expected. Complete occlusion of the aneurysm can be performed safely, even if loops of coils protrude into the aneurysmal neck. In these cases intraoperative removal of the coils enables secure closure of the aneurysm with a surgical clip.

Is packing density important in stent-assisted coiling?

BACKGROUND

Recent reports have shown that stent-assisted coiling (SAC) is associated with lower aneurysm recanalization rates compared with conventional coiling, raising questions about the necessity of achieving high packing density (PD) in stented aneurysms.

OBJECTIVE

To assess the impact of PD on follow-up obliteration rates of stented aneurysms and attempt to determine the optimal range of PD in SAC.

METHODS

This is a retrospective analysis of a single, large, cerebrovascular referral center's experience over a 5-year period in SAC with the use of Neuroform and Enterprise stents. The rate of complete obliteration on follow-up angiograms was compared for 3 different PD groups: high PD (>22%), moderate PD (12-22%), and low PD (<12%).

RESULTS

There were 292 stent-coiled aneurysms (36 ruptured, 256 unruptured) with available angiographic follow-up. Mean PD was 15.2%, and complete obliteration rate was 79.5% at latest follow-up. The rates of complete obliteration were significantly higher in the moderate (86.4%; OR = 2.58; P = .006) and high PD groups (85.3%; OR = 2.35; P = .037) compared with the low PD group (71.1%). However, no statistically significant difference was found between the moderate and high PD groups (OR = 0.91; P = .84). In multivariate analysis, PD was a significant predictor of complete obliteration (P = .007) along with smaller aneurysm volumes (P = .004). Ruptured (P = .002) and cavernous aneurysms (P < .001) had significantly lower obliteration rates.

CONCLUSION

High obliteration rates at follow-up were observed despite modest packing of stented aneurysms. Although PD is a definite factor in SAC, moderate and high packing of stented aneurysms seems to provide equivalent angiographic obliteration rates at follow-up.

Interobserver agreement after pipeline embolization device implantation

BACKGROUND AND PURPOSE

Although flow diversion devices are popular in treatment of aneurysms, angiographic assessment with these devices has rarely been verified by interobserver variability study. The purpose of this study was to determine the interobserver agreement of a 3-point grading system for assessing the angiographic outcome after flow diversion therapy of intracranial, saccular aneurysms and to determine factors affecting such agreement.

MATERIALS AND METHODS

After approval by the institutional review board, 5 independent readers assessed pretreatment and follow-up digital subtraction angiograms from 96 patients treated with the Pipeline embolization device by using a 3-point grading system (complete, near-complete, and incomplete occlusion). "Minor discrepancy" was defined as a difference between any 2 readers of 1 grade, that is, complete vs near-complete or near-complete vs incomplete. "Major discrepancy" was defined as a difference between any 2 readers in which 1 reader noted complete occlusion and the other reader noted incomplete occlusion. We performed statistical analysis for the interobserver agreement by using the intraclass correlation coefficient. Subgroup analyses for discrepancy rate and ICC were performed for previously coiled aneurysms.

RESULTS

The interobserver agreement was excellent (ICC, 0.76; 95% CI, 0.69-0.92). Among 96 cases, there was absolute agreement in 74 (77%), of which 67 had unanimous consensus of "complete" occlusion, 2 "near-complete" occlusion, and 5 "incomplete" occlusion. Discordance between any 2 readers was noted in 22 cases (23%), of which 7 (7.3%) revealed a major discrepancy. Subgroup analysis showed that minor discrepancies were more common among patients previously treated with coils vs those not previously treated with coils (37.5% vs 11.2%; P < .05).

CONCLUSIONS

The observer agreement regarding occlusion after PED therapy is excellent. Only a minority of cases demonstrated discrepancy considered as major in this study.