Endovascular treatment of intracranial aneurysms with matrix coils: immediate posttreatment results, clinical outcome and follow-up

Autologous adipose-derived mesenchymal stem cells improve healing of coiled experimental saccular aneurysms: an angiographic and histopathological study

PURPOSE

Long-term occlusion of coiled aneurysms frequently fails, probably because of poor intrasaccular healing and inadequate endothelialization across the aneurysm neck. The purpose of this study was to determine if attachment of autologous mesenchymal stem cells (MSCs) to platinum coils would improve the healing response in an elastase-induced aneurysm model in rabbits.

MATERIALS AND METHODS

With approval from the institutional animal care and use committee, aneurysms were created in rabbits and embolized with control platinum coils (Axium; Medtronic) (n=6) or coils seeded ex vivo with autologous adipose-tissue MSCs (n=7). Aneurysmal occlusion after embolization was evaluated at 1 month with angiography. Histological samples were analyzed by gross imaging and graded on the basis of neck and dome healing on H&E staining. Fibrosis was evaluated using a ratio of the total area presenting collagen. Endothelialization of the neck was quantitatively analyzed using CD31 immunohistochemistry. χ² and Student's t-test were used to compare groups.

RESULTS

Healing score (11.5 vs 8.0, p=0.019), fibrosis ratio (10.3 vs 0.13, p=0.006) and endothelialization (902 262 μm² vs 31 810 μm², p=0.041) were significantly greater in the MSC group. The MSC group showed marked cellular proliferation and thrombus organization, with a continuous membrane bridging the neck of the aneurysm. Angiographic stable or progressive occlusion rate was significantly lower in the MSC group (0.00, 95% CI 0.00 to 0.41) compared with controls (0.67, 95% CI 0.22 to 0.96) (p=0.02).

CONCLUSIONS

Autologous MSCs attached to platinum coils significantly improve histological healing, as they result in improved neck endothelialization and collagen matrix formation within the aneurysm sac.

Results of endovascular treatment of aneurysms depending on their size, volume and coil packing density

BACKGROUND AND PURPOSE

In contrast to neurosurgery, which is more efficient, endovascular treatment (EVT) is less invasive. The main purpose of EVT is complete occlusion of the aneurysm and protection from subarachnoid haemorrhage. Accurate measurements of the aneurysm (size, volume) obtained using a 3D digital subtraction angiography (DSA) workstation can assist in the proper assessment of coil packing density (CPD), which affects possible distant recanalization. The main disadvantage of endovascular treatment of intracranial aneurysms compared to neurosurgery is the high recurrence rate. We evaluated the results of endovascular treatment of aneurysms depending on their size, volume and coil packing density.

MATERIAL AND METHODS

Thirty-five patients with intracranial aneurysms underwent endovascular embolization with bare platinum coils. Three-dimensional DSA was used to evaluate aneurysms' morphology. Eighteen patients underwent 3D DSA follow-up 6-45 months after treatment. Initial and follow-up results of embolization were assessed with the Raymond-Montreal scale. The impact of aneurysms' morphology, volume and initial CPD on endovascular treatment was evaluated.

RESULTS

Among 35 patients, complete initial embolization was achieved in 74%. Mean initial aneurysm volume in 3D DSA was 0.517 mL and decreased significantly after embolization. Initial CPD varied from 74% to 2% depending on aneurysm diameter (12.1% for aneurysms ≥ 10 mm, 22.5% for aneurysms < 10 mm). Results of embolization on the Raymond-Montreal scale significantly depended on aneurysms' CPD. Aneurysms' recanalization rate on 3D DSA follow-up was 36%, with complete recanalization in 3.3%.

CONCLUSIONS

We can achieve a better outcome if size and volume of the aneurysm sac is smaller and if CPD is higher.

Autologous mesenchymal stem cell endografting in experimental cerebrovascular aneurysms

INTRODUCTION

Coiling is the gold standard for the treatment of intracranial aneurysms. However, some issues associated with endovascular treatment limit its long-term efficiency. Recanalization with coil compaction is certainly the most important. New approaches may be considered to promote thrombus colonization by mesenchymal cells and aneurysm healing. In the present study, we have percutaneously delivered autologous bone marrow mesenchymal stem cells (BMSCs) to an elastase-induced rabbit carotid aneurysm model in vivo.

METHODS

Autologous mesenchymatous stem cells were obtained after femoral puncture and bone marrow aspiration. After 2 weeks of in vitro cell culture, five million BMSCs were grafted in the carotid aneurysm using an endovascular approach.

RESULTS

We demonstrated the feasibility of in vivo percutaneous seeding of autologous BMSCs in the aneurysm by positive Hoechst fluorostaining. Two weeks later, conventional angiography showed an increase in median aneurysmal surface in the sham group, whereas this surface was decreased in the group treated with BMSCs, +28.4 versus -26.4 %, respectively (p = 0.01). BMSC seeding resulted in intimal hyperplasia with cell colonization and disappearance of the thrombus.

CONCLUSION

In conclusion, percutaneous seeding of BMSCs may colonize and heal the arterial wall thus limiting aneurysm expansion.

Bare platinum vs matrix detachable coils for the endovascular treatment of intracranial aneurysms: a multivariate logistic regression analysis and review of the literature

BACKGROUND

Despite increasing acceptance of endovascular coiling for treating intracranial aneurysms, incomplete occlusion remains a limitation. Attempts to reduce recanalization have prompted creation of polyglycolic/polylactic acid-coated (Matrix) coils shown to improve neointima formation; however, previous publications demonstrate conflicting results regarding their efficacy. Few studies account for factors influencing recurrence, and only 4 studies include bare platinum (BP) coil control groups.

OBJECTIVE

To compare initial and short- and mid-term occlusion as well as retreatment rates using Matrix compared with BP coils.

METHODS

Retrospective review of patients undergoing coiling of cerebral aneurysms from 2001 to 2005 was performed. Analysis included a multivariate logistic regression model designed to detect a 35% absolute difference in initial occlusion between coil treatment groups with 80% power.

RESULTS

Complete initial occlusion was achieved in 64% of BP (n = 45) and 63% of Matrix (n = 56) cases (P = 1.0). Follow-up occlusion rates in the short term and mid term were 52% and 60%, respectively, for BP cases and 42% and 67%, respectively, for Matrix cases (P = .24 and P = .38, respectively). After adjusting for size, morphology, volumetric packing density, location, rupture, and balloon remodeling, no difference in initial and subsequent occlusion or retreatment rates for BP coils versus Matrix coils was appreciated.

CONCLUSION

After controlling for factors influencing recanalization, this investigation failed to show a significant difference between coil groups.

The Barrow Ruptured Aneurysm Trial

OBJECT

The purpose of this ongoing study is to compare the safety and efficacy of microsurgical clipping and endovascular coil embolization for the treatment of acutely ruptured cerebral aneurysms and to determine if one treatment is superior to the other by examining clinical and angiographic outcomes. The authors examined the null hypothesis that no difference exists between the 2 treatment modalities in the setting of subarachnoid hemorrhage (SAH). The current report is limited to the clinical results at 1 year after treatment.

METHODS

The authors screened 725 patients with SAH, resulting in 500 eligible patients who were enrolled prospectively in the study after giving their informed consent. Patients were assigned in an alternating fashion to surgical aneurysm clipping or endovascular coil therapy. Intake evaluations and outcome measurements were collected by nurse practitioners independent of the treating surgeons. Ultimately, 238 patients were assigned to aneurysm clipping and 233 to coil embolization. The 2 treatment groups were well matched. There were no anatomical exclusions. Crossing over was allowed, but primary outcome analysis was based on the initial treatment modality assignment. Posttreatment care was standardized for both groups. Patient outcomes at 1 year were independently assessed using the modified Rankin Scale (mRS). A poor outcome was defined as an mRS score > 2 at 1 year. The primary outcome was based on the assigned group; that is, by intent to treat.

RESULTS

One year after treatment, 403 patients were available for evaluation. Of these, 358 patients had actually undergone treatment. The remainder either died before treatment or had no identifiable source of SAH. A poor outcome (mRS score > 2) was observed in 33.7% of the patients assigned to aneurysm clipping and in 23.2% of the patients assigned to coil embolization (OR 1.68, 95% CI 1.08-2.61; p = 0.02). Of treated patients assigned to the coil group, 124 (62.3%) of the 199 who were eligible for any treatment actually received endovascular coil embolization. Patients who crossed over from coil to clip treatment fared worse than patients assigned to coil embolization, but no worse than patients assigned to clip occlusion. No patient treated by coil embolization suffered a recurrent hemorrhage.

CONCLUSIONS

One year after treatment, a policy of intent to treat favoring coil embolization resulted in fewer poor outcomes than clip occlusion. Although most aneurysms assigned to the coil treatment group were treated by coil embolization, a substantial number crossed over to surgical clipping. Although a policy of intent to treat favoring coil embolization resulted in fewer poor outcomes at 1 year, it remains important that high-quality surgical clipping be available as an alternative treatment modality.

Attributing hypodensities on CT to angiographic vasospasm is not sensitive and unreliable

BACKGROUND AND PURPOSE

The presence of low-density areas on CT is used in clinical decision-making regarding treatment of angiographic vasospasm as well as in research as a surrogate marker for severity of angiographic vasospasm. We assess the interobserver variability in attributing hypodensities on CT to angiographic vasospasm-related delayed ischemic neurological deficit.

METHODS

Three experienced reviewers, 2 neurosurgeons, and a neuroradiologist independently reviewed CT scans of 413 patients enrolled in the Clazosentan to Overcome Neurological iSChemia and Infarction OccUrring after Subarachnoid hemorrhage (CONSCIOUS-1) trial, who universally underwent catheter angiography to determine severity of angiographic vasospasm. Interobserver variability was calculated using the κ statistic and the χ(2) test was used to determine associations between dichotomized outcomes.

RESULTS

There was considerable interobserver variability in attributing CT hypodensities to vasospasm-related delayed ischemic neurological deficit (κ=0.51-0.78; 95% CI, 0.35-0.90). Patients with hypodensities attributed to delayed ischemic neurological deficit were significantly more likely to have severe angiographic vasospasm (P=0.001), but a substantial proportion of these patients (19%) also had mild or no spasm. CT hypodensities had a sensitivity and specificity of 41% and 93%, respectively, in identifying patients with severe angiographic vasospasm, even with expert consensus that these represent angiographic vasospasm-related delayed ischemic neurological deficit.

CONCLUSIONS

We find considerable interobserver variability in attributing CT hypodensities to angiographic vasospasm and propose that they may not be a robust marker of severity of angiographic vasospasm, even with unanimous expert agreement that they are a result of vasospasm-related delayed ischemic neurological deficit.

CLINICAL TRIAL REGISTRATION

URL: www.clinicaltrials.gov. Unique identifier: NCT00111085.

Matrix² coils in embolization of intracranial aneurysms: 1-year outcome and comparison with bare platinum coil group in a single institution

BACKGROUND AND PURPOSE

The endosaccular occlusion by using BPC has been useful in the treatment of intracranial aneurysms, but its limited durability remains a deep-seated drawback. The Matrix² coil, one of the bioactive-coated coils, had been developed to improve this limited durability. To evaluate durability of Matrix² coils after embolization of intracranial aneurysms, we retrospectively compared 1-year outcomes with that of BPC groups.

MATERIALS AND METHODS

A group of 121 aneurysms in 114 patients were embolized by using Matrix² coils between April 2006 and September 2008. The BPC group consisted of 151 aneurysms in 137 patients embolized by using BPCs alone between October 2007 and October 2008. The initial outcomes including packing densities, occlusion grades, and periprocedural complications, and the 1-year outcomes on MR angiography were retrospectively compared between the 2 groups.

RESULTS

The Matrix² coil group and BPC group with similar baseline demographic characteristics revealed comparable initial outcomes. The rates of overall recurrence, major recanalization, and retreatment were 17.4%, 14.0%, and 10.7% versus 7.3%, 5.3%, and 4.6%, respectively (P = .066). However, the rates of subgroups with aneurysm volumes between 50 and 200 mm³ were 23.7%, 13.1%, and 10.5% versus 2.2%, 0%, and 0% (P = .022), respectively. The rates of subgroups with packing attenuation <30% were 38.3%, 31.9%, and 23.4% versus 13.3%, 11.7%, and 10% (P = .025), respectively. There were no differences in packing attenuation (P = .152), initial occlusion grade (P = .098), and 1-year outcomes (P = .209) according to the length of Matrix² coils used.

CONCLUSIONS

Overall, initial and 1-year outcomes of the Matrix² coil group were comparable to those of the BPC group. However, in certain subgroups of aneurysm volume and packing attenuation, the 1-year durability of Matrix² coils was inferior to that of the BPC group.

Endovascular treatment of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage is a deadly disease associated with high morbidity and mortality. Surgical clipping has been the gold standard treatment for more than 70 years. Endovascular therapy is now accepted as a valid alternative therapeutic modality. The authors' approach emphasizes collaboration between endovascular and surgical specialists. The array of new endovascular techniques has extended beyond the Guglielmi Detachable Coil to include new stents and flow-diverting devices. The future promises expansion of the number of types of aneurysms that are treatable with endovascular techniques.

Clinical experience with Matrix2 360 degrees coils in the treatment of 100 intracranial aneurysms

BACKGROUND

The M2-360 degrees is a recent class of aneurysm coil. This device combines the second generation of bioactive copolymer coating, which is intended to promote aneurysm fibrosis, with the "360 degrees " design, which is meant to improve uniformity and density of packing. This study evaluates the safety and angiographic stability of these devices.

METHODS

This was a retrospective review of 86 consecutive patients with 100 intracranial aneurysms that were treated using M2-360 degrees s. Follow-up was done at 6 and 12 months.

RESULTS

Seventy-eight aneurysms were coiled solely with M2-360 degrees s, and 22 aneurysms were treated with a combination of coils. In mixed-coil cases, the average percentage of coil volume consisting of M2-360 degrees coils was 78%. Procedure-related neurologic complications occurred in 6 patients (7%). Initial complete occlusion was obtained in 80 aneurysms. Of 76 aneurysms with 6-month angiographic follow-up, 4 (5.3%) revealed further occlusion, 54 (71.1%) were unchanged, and 18 (23.7%) showed recanalization. Of 38 aneurysms with 12-month follow-up, 1 (2.6%) revealed further occlusion, 23 (60.5%) were unchanged, and 14 (36.8%) showed recanalization. Six- and 12-month angiograms showed major recanalization (requiring further coiling) in 3.9% and 15.8% of cases, respectively.

CONCLUSIONS

The risk of complications with M2-360 degrees -treated aneurysms is comparable with reports of other coils, indicating that M2-360 degrees s are relatively safe. Although the initial occlusion rate is higher than that in other coiling series, recanalization rates were similar to those obtained with other coil designs. This study does not demonstrate an advantage with M2-360 degrees s.

Clinical and angiographic follow-up of ruptured intracranial aneurysms treated with endovascular embolization

BACKGROUND AND PURPOSE

Endovascular embolization is a well-established treatment of ruptured intracranial aneurysms, but concern about its long-term stability and its ability to prevent rehemorrhage are still present. We evaluated the long-term clinical and angiographic follow-up of patients with ruptured cerebral aneurysms treated with coiling, focusing on rehemorrhage and changes in aneurysm morphologic features.

MATERIALS AND METHODS

A total of 377 patients with ruptured aneurysms that were treated with endovascular approaches at our institution between 1994 and 2008 were reviewed. Clinical and angiographic data were analyzed from a prospectively collected data base.

RESULTS

There were 377 patients with 391 ruptured aneurysms treated for 14 years. Good outcome (Glasgow Outcome Score [GOS], 5) was achieved in 74% of patients, moderate disability or poor outcome in 18%, and 8.8% died. Permanent morbidity or mortality from procedural complications occurred in 2.9%. Complete follow-up was available for 85% of surviving patients, with mean follow-up of 22.3 months. Re-treatment was required in 11% (31 patients). Eight (2.1%) patients had rebleeding, 6 (1.6%) in the hospital within 30 days of treatment, 5 in the first 48 hours. Follow-up imaging was available in 276 aneurysms in 270 patients. Recanalization occurred in 56 of 276 aneurysms (20.3%) regardless of the initial angiographic result, but the risk was higher if a body remnant was left (chi2, 11.791; P = .0006).

CONCLUSIONS

Long-term clinical and angiographic follow-up demonstrates the efficacy of endovascular treatment of ruptured intracranial aneurysms. Rebleeding after treatment is rare, with the greatest risk during the first 48 hours after treatment. Initial angiographic results are not a useful predictor of clinical outcome or rehemorrhage.

Endovascular coiling of cerebral aneurysms using "bioactive" or coated-coil technologies: a systematic review of the literature

SUMMARY

Second-generation coils have been available since 2002. We wanted to assess their performance and appraise available evidence. Therefore we performed a systematic review of the literature from 2002 to 2007. There were 27 studies with a total of 2390 patients that met pre-specified inclusion criteria. All studies were classed as having a high risk of bias. There were no randomized trials and for most studies results were not independently assessed and follow-up periods were short (mean 7 months). There were large differences in demographic and aneurysm characteristics, making comparisons between coil cohorts difficult. Procedure-related morbidity and mortality were similar for all coil types. Hemorrhagic events during follow-up were few, in the range of 1%/year for all coil types. The available literature is of poor quality and clinical series provide very little evidence in favor of second-generation coils. Positive randomized trial results are needed to justify routine clinical use. This systematic review illustrates the failure of the industry, the regulatory authorities, and the neurointerventional community combined to provide a reliable and prudent approach to the introduction of new devices.

Coils in a nutshell: a review of coil physical properties

Since its inception, endovascular coil technology has grown substantially as multiple manufacturers entered the market with an ever-increasing number of new products. Practitioners are now inundated with a choice of coils that vary on the basis of factors such as size, composition, stiffness, and detachment mechanism. The seasoned interventionalist had the benefit of evolving with this technology and, therefore, is likely to understand many of the practical nuances of coil development; for more junior practitioners, who did not experience the ongoing changes in technology, this review will provide a basic framework for the fundamentals of coil design.

Molecular Indices of Apoptosis Activation in Elastase-Induced Aneurysms After Embolization With Platinum Coils

BACKGROUND AND PURPOSE

Even though endovascular coils have been widely used for the treatment of intracranial aneurysms, the cellular and molecular responses of aneurysms to the coils after embolization remain poorly understood. The aim of the present study was to understand the mechanism of apoptosis in aneurysms embolized with platinum coils in the rabbit model of elastase-induced aneurysms.

METHODS

Elastase-induced saccular aneurysms were created at the origin of the right common carotid artery in 30 rabbits. Aneurysms were allowed to mature for 8 weeks, after which 20 aneurysms were embolized with platinum coils by endovascular means. After 2 (n=10) and 4 (n=10) weeks of implantation, aneurysm samples harboring coils were harvested for apoptotic studies. The remaining 10 uncoiled aneurysms were used as controls; additional controls included the left common carotid artery, which had not undergone any surgical procedure. Control samples were harvested at 12 weeks after aneurysm creation.

RESULTS

Expression of procaspases-3, -8, and -9 was elevated in coiled aneurysms embolized with platinum coils at both time points when compared with uncoiled aneurysms and the left common carotid artery. Cleaved caspases-3, -8, and -9 were found to be expressed only at 4 weeks after embolization. Cells within the aneurysm cavity were terminal dUTP nick end-labeling-positive at 4 weeks only. These apoptotic cells were identified as smooth muscle actin-positive cells. Expression of tumor necrosis-alpha was high in coiled aneurysms when compared with controls. There was no significant difference in the expression of Fas ligand among groups. Decreased expression of antiapoptotic proteins Bcl-2 and phospho-Bad, as well as increased expression of proapoptotic proteins Bax and Bid, was observed in coiled aneurysms at both time points.

CONCLUSIONS

Activation of apoptosis in aneurysms after embolization with platinum coils is induced by both tumor necrosis factor-alpha-mediated extrinsic and Bcl-2-mediated intrinsic pathways.