Safety and efficacy of the Derivo Embolization Device for the treatment of ruptured intracranial aneurysms

Treatment of ruptured intracranial aneurysms using the novel generation of flow-diverters with surface modification: A systematic review and meta-analysis

BACKGROUND

Surface modification of flow diverters (FDs) has been explored as a solution for reducing thrombotic risk of these devices, without necessarily using dual antiplatelet therapy (DAPT). If effective, this could pose a promising alternative for treatment of ruptured aneurysms not amenable to other modalities.

METHODS

We performed a comprehensive search of PubMed, MEDLINE, and Embase databases following Preferred Reporting Items for Systematic reviews and Meta-analyzes guidelines. We included articles reporting use of surface-modified FDs for treatment of ruptured aneurysms. Demographics, subarachnoid hemorrhage (SAH) severity, aneurysm characteristics, devices used, periprocedural complications, angiographic outcomes, and mortality were extracted for sample size-based weighted analysis.

RESULTS

Six studies comprising 59 patients with 64 aneurysms were included. Mean patient age was 56.6 ± 6.3 years and 60.6% (95% confidence interval [CI], 46.7-72.9%) were women. The anterior circulation was the location in 60.4% (95%CI, 45.5-73.5%) of aneurysms; 41.8% of the aneurysms were saccular (95%CI, 29.3-55.4%), 16.7% were fusiform (95%CI, 8.3-30.8%), 29.9% were dissecting (95%CI, 12.8-55.4%), 24.4% were blood-blister (95%CI, 15.2-36.7%), and 5.7% were mycotic (95%CI, 2-15.1%). Poor SAH grade was reported in 46.9% (95%CI, 33.3-60.9%). Adjunctive coiling was used in 33.2% (95%CI, 12.4-63.6%). Periprocedural thromboembolic and hemorrhagic complications occurred in 20% (95%CI, 7.1-45.1%) and 8.8% (95%CI, 3.7-19.5%), respectively. Complete occlusion was achieved in 76.4% (95%CI, 58.1-88.3%); no retreatments during follow-up were reported. Overall mortality was 15.1% (95%CI, 7.7-27.6%). There were no differences between single antiplatelet therapy (SAPT) and DAPT regimens with respect to periprocedural thromboembolic complications (P = 0.09), hemorrhagic (P = 0.834) complications, and mortality (P = 0.312).

CONCLUSION

Surface-modified FD treatment of ruptured aneurysms resulted in high rates of thromboembolic complications and acceptable rates of hemorrhagic complications. A considerable proportion of aneurysms were nonsaccular. Rates of complete occlusion were high and retreatment were low. Importantly, no statistically significant difference was found between SAPT and DAPT with respect to complications and mortality.

OnyxTMGel or Coil versus Hydrogel as Embolic Agents in Endovascular Applications: Review of the Literature and Case Series

This review focuses on the use of conventional gel or coil and "new" generation hydrogel used as an embolic agent in endovascular applications. In general, embolic agents have deep or multidistrict vascular penetration properties as they ensure complete occlusion of vessels by exploiting the patient's coagulation system, which recognises them as substances foreign to the body, thus triggering the coagulation cascade. This is why they are widely used in the treatment of endovascular corrections (EV repair), arteriovenous malformations (AVM), endoleaks (E), visceral aneurysms or pseudo-aneurysms, and embolisation of pre-surgical or post-surgical (iatrogenic) lesions. Conventional gels such as Onyx or coils are now commercially available, both of which are frequently used in endovascular interventional procedures, as they are minimally invasive and have numerous advantages over conventional open repair (OR) surgery. Recently, these agents have been modified and optimised to develop new embolic substances in the form of hydrogels based on alginate, chitosan, fibroin and other polymers to ensure embolisation through phase transition phenomena. The main aim of this work was to expand on the data already known in the literature concerning the application of these devices in the endovascular field, focusing on the advantages, disadvantages and safety profiles of conventional and innovative embolic agents and also through some clinical cases reported. The clinical case series concerns the correction and exclusion of endoleak type I or type II appeared after an endovascular procedure of exclusion of aneurysmal abdominal aortic (EVAR) with a coil (coil penumbra released by a LANTERN microcatheter), the exclusion of renal arterial malformation (MAV) with a coil (penumbra coil released by a LANTERN microcatheter) and the correction of endoleak through the application of Onyx 18 in the arteries where sealing by the endoprosthesis was not guaranteed.

The DERIVO 2heal embolisation device: A technical report using single antiplatelet therapy for intracranial pseudoaneurysm treatment

The novel DERIVO 2heal Embolisation Device (Acandis, Pforzheim, Germany) is a flexible, fully radiopaque flow-diverter with a fibrin-based nano-coating, which is supposed to make the device inert to the coagulation cascade. We report a case of pseudoaneurysm treatment with this device under single anti-platelet therapy (SAPT). A female patient underwent endoscopic surgery for chronic rhinosinusitis. During surgery, the lateral wall of the sphenoid wall and the adjacent internal carotid artery was injured, leading to massive hemorrhage, which was treated with compression and tamponades. Eleven days after the procedure, the patient developed a rapidly growing pseudoaneurysm at the injury site with a relevant risk of upcoming aneurysm rupture. The aneurysm was treated by implantation of a DERIVO 2heal. A SAPT regimen was chosen due to the recent massive hemorrhage and anticipating enhanced progressive aneurysm occlusion. There were no thromboembolic complications and there was no morbidity. After 5 days, the pseudoaneurysm was completely occluded. The observations of the presented case are promising and warrant further investigation of this device.

First clinical experience with the Derivo 2heal embolization device for the treatment of intracranial aneurysms

OBJECTIVE

The development of new flow-diverting devices with antithrombotic coatings may result in an improved safety profile, particularly a reduction in ischaemic stroke rates. The aim of this study was to evaluate our initial experience with the recently introduced coated Derivo® 2heal® Embolization Device (Acandis, Pforzheim, Germany).

METHODS

This is a retrospective, single-centre analysis of patients with intracranial aneurysms undergoing Derivo® 2heal® Embolization Device treatment. Patient and aneurysm characteristics, procedural parameters, complications, and degree of initial and short-term aneurysm occlusion were evaluated on an intention-to-treat basis.

RESULTS

A total of 16 unruptured aneurysms in 9 patients were treated with the Derivo® 2heal® Embolization Device in 10 treatment sessions. In one case the Derivo® 2heal® Embolization Device could not be deployed due to severe friction in the microcatheter. In all successful cases, one Derivo® 2heal® Embolization Device was sufficient to treat the target aneurysm and no additional coiling was performed. In-stent balloon angioplasty was performed in one procedure (10%) to improve vessel wall apposition. Twelve arterial side branches were covered in 9 procedures and all were patent at the end of the procedure. There were no clinical complications and no thromboembolic events during treatment. At the end of the procedure, contrast retention was observed in 13/16 (81%) aneurysms and at short-term follow-up, 6/9 (67%) were completely occluded.

CONCLUSIONS

The preliminary results of the new Derivo® 2heal® Embolization Device appear promising and warrant further evaluation by multicentre studies with long-term follow-up.

Small Unruptured Intracranial Aneurysms Can Be Effectively Treated With Flow-Diverting Devices

Purpose

To investigate the effect and safety of flow diverters in the management of small (<10 mm in diameter) unruptured intracranial aneurysms.

Materials and Methods

One hundred and ten patients with 145 small intracranial aneurysms treated with flow diverters were retrospectively enrolled. The clinical, endovascular, and follow-up data were analyzed.

Results

One hundred twenty-one flow diverters were deployed for the treatment of 145 small intracranial aneurysms in 110 patients, and the stenting success rate was 99.1%. In 133 (91.7%) aneurysms, only flow-diverting devices were deployed, and in the rest 12 (8.3%) of aneurysms, coils were used to loosely pack the aneurysm after deployment of a flow-diverting device. Five patients (4.5%) experienced ischemic complications, but no hemorrhagic complications were occurred. All patients had clinical follow-up 6-18 (median 12) after the procedure, with the modified Rankin scale score (mRS) 0 in 101 patients, 1 in four patients, 2 in three patients, 4 in one patient, and 5 in one patient. Digital subtraction angiography was performed at follow-up in 90 (81.8%) patients with 118 (81.4%) aneurysms 6-18 months (median 12) after the procedure, with the Raymond grade I in 90 (76.2%) aneurysms and Raymond grade III in 28 (23.7%). Eighteen patients with 22 partially occluded aneurysms at the first angiographic follow-up experienced the second digital subtraction angiography 12-36 months (median 26) after the procedure, and 21 (95.5%) aneurysms were completely occluded. Two patients had asymptomatic in-stent stenosis.

Conclusion

Treatment of small unruptured intracranial aneurysms with flow diverters can be performed safely and effectively with satisfactory outcomes.

Outcomes after Flow Diverter Treatment in Subarachnoid Hemorrhage: A Meta-Analysis and Development of a Clinical Prediction Model (OUTFLOW)

Background: patients with a subarachnoid hemorrhage (SAH) might need a flow diverter (FD) placement for complex acutely ruptured intracranial aneurysms (IAs). We conducted a meta-analysis and developed a prediction model to estimate the favorable clinical outcome after the FD treatment in acutely ruptured IAs. Methods: a systematic literature search was performed from 2010 to January 2021 in PubMed and Embase databases. Studies with more than five patients treated with FDs within fifteen days were included. In total, 1157 studies were identified. The primary outcome measure was the favorable clinical outcome (mRS 0–2). Secondary outcome measures were complete occlusion rates, aneurysm rebleeding, permanent neurologic deficit caused by procedure-related complications, and all-cause mortality. A prediction model was constructed using individual patient-level data. Results: 26 retrospective studies with 357 patients and 368 aneurysms were included. The pooled rates of the favorable clinical outcome, mortality, and complete aneurysm occlusion were 73.7% (95% CI 64.7–81.0), 17.1% (95% CI 13.3–21.8), and 85.6% (95% CI 80.4–89.6), respectively. Rebleeding occurred in 3% of aneurysms (11/368). The c-statistic of the final model was 0.83 (95% CI 0.76–0.89). All the studies provided a very low quality of evidence. Conclusions: FD treatment can be considered for complex ruptured IAs. Despite high complication rates, the pooled clinical outcomes seem favorable. The prediction model needs to be validated by larger prospective studies before clinical application.

A systematic review and meta-analysis of the Derivo Embolization Device: a novel surface-modified flow diverter for intracranial aneurysm treatment

BACKGROUND

Surface-modified flow diverters (FDs) designed to reduce thrombogenicity represent the next frontier for intracranial aneurysm treatment. The Derivo Embolization Device (DED) is a novel FD with titanium oxide and titanium oxynitride finishing of the struts. We performed a systematic review of pertinent literature, aiming to evaluate the device's effectiveness and safety.

METHODS

A literature search of PubMed, Embase, and MEDLINE was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Five studies comprising 481 aneurysms were included. These studies were conducted in Turkey, Brazil, Germany, Poland, and Italy; two were prospective and three were retrospective. Twenty-six aneurysms (5.4%) were ruptured. The antiplatelet regimens were heterogeneous, but dual antiplatelet therapy was administered preprocedurally in all studies and maintained for 3-12 months before a switch to single antiplatelet therapy. The rate of periprocedural ischemic and hemorrhagic complications was 4.9% (95% CI 2.9% to 7%). Adjunctive coiling was used in 25.6% (95% CI 11.4% to 39.8%) of aneurysms. The complete angiographic occlusion rate was 81.4% (95% CI 71.3% to 91.5%), mortality rate was 2.1% (95% CI 0.4% to 3.9%), with follow-up ranging from 9 to 18 months. Delayed aneurysm rupture was reported in one patient.

CONCLUSIONS

The DED has been increasingly used in other countries. We identified low rates of periprocedural complications and mortality and a high rate of complete occlusion.

Flow diversion for acutely ruptured intracranial aneurysms treatment: A retrospective study and literature review

OBJECTIVE

Flow diversion is becoming an increasingly established practice for the treatment of acutely ruptured intracranial aneurysms. In this study the authors present a literature review and meta-analysis, adding a retrospective review of institutional registry on emergency treatment of aRIA with flow diverter stent.

MATERIALS AND METHODS

A systematic search of PubMed, SCOPUS, Ovid MEDLINE, and Ovid EMBASE was performed on April 20^th, 2021, extrapolating 35 articles. R language 'meta' and 'metafor' packages were used for data pooling. The DerSimonian-Laird model was used to calculate the pooled effect. The I² value and Q statistic evaluated study heterogeneity. Additionally, the authors retrospectively reviewed their institutional database for the treatment and outcomes of all patients with acutely ruptured intracranial aneurysms treated with flow diverter stent placement from May 2010 to November 2020 was performed.

RESULTS

From the systematic literature review and meta-analysis, the pooled proportion of complete aneurysm occlusion was 78%, with a pooled rate of 79%, 71%, 80%, and 50% for dissecting, saccular, fusiform, and mycotic aneurysms, respectively. The pooled proportion of aneurysm rebleeding and intrastent stenosis was 12% and 15% respectively, for a total of 27% rate. The analysis of authors retrospective register showed an overall mortality rate of 16.7% (3/18), with a low but not negligible postprocedural rebleeding and intrastent thrombosis rates (5.6% and 11.1% respectively).

CONCLUSION

Although increasingly utilized in the management of selected patients with acutely ruptured intracranial aneurysms, flow diversion for acutely ruptured intracranial aneurysms treatment presents rebleeding and intrastent stenosis rates not negligible.

Hemodynamic Characteristics and Clinical Outcome for Intracranial Aneurysms treated with the Derivo Embolization Device, a Novel Second-Generation Flow Diverter

BACKGROUND AND PURPOSE

We investigated the relationship between hemodynamic characteristics and clinical outcomes for aneurysms treated by the Derivo Embolization Device (DED), a novel second-generation Flow-Diverter Stent, using computational fluid dynamics (CFD).

MATERIALS AND METHODS

Data were retrospectively obtained from two centers between 2017 and 2019. During the period, 23 patients were treated for 23 aneurysms with DED. In 17 patients we were able to conduct CFD analysis as six were excluded due to pre-coiling, unsuitable arterial geometry, and complex geometric form. Aneurysm occlusion was rated with the O`Kelly-Marotta (OKM) grading scale on DSA 6 months after stent placement in all patients. Hemodynamic and morphological parameters were statistically compared between two groups: with full occlusion and with a remnant.

RESULTS

Full occlusion was observed in 17 out of 23 (73.9%) patients. In the group suitable for CFD analysis, we observed 13 fully occluded aneurysms and 4 with any remnant (specifically 1 OKM C, 1 B and 2 A). The energy loss per volume (ELV), which indicates the energy loss through the aneurysm, was significantly larger in pre and post stenting (p<.05) in the complete occlusion cases. In addition, the inflow concentration index (ICI) and inflow area ratio (IAR) of the remnant cases were significantly larger and lower, respectively (p<.05).

CONCLUSION

Our CFD results indicate that the energy loss involved with the blood flow passing through an aneurysm and concentrated inflow into aneurysm were the most important factors to determine whether an aneurysm will become a complete occlusion or remnant case.

Propensity score-adjusted analysis on stent-assisted coiling versus coiling alone for ruptured intracranial aneurysms

Stent-assisted coiling (SAC) for ruptured intracranial aneurysms (RIAs) remains controversial due to an inherent risk of potential thromboembolic and hemorrhagic complications. We compared SAC and coiling alone for the management of RIAs using propensity score-adjustment. Sixty-four patients treated by SAC and 220 by stand-alone coiling were retrospectively reviewed and compared using inverse probability of treatment weighting (IPTW) with propensity scores. Functional outcome, procedure-related and overall complications and angiographic results were analyzed. Aneurysms treated by SAC had a larger diameter, a wider neck and were more frequently located at the posterior circulation. SAC had a higher risk for thromboembolic complications (17.2% vs. 7.7%, p = 0.025), however, this difference did not persist in the IPTW analysis (OR 1.2, 95% CI 0.7-2.3, adjusted p = 0.458). In the adjusted analysis, rates of procedural cerebral infarction (p = 0.188), ventriculostomy-related hemorrhage (p = 0.584), in-hospital mortality (p = 0.786) and 6-month favorable functional outcome (p = 0.471) were not significantly different between the two groups. SAC yielded a higher complete occlusion (80.0% vs. 67.2%, OR 3.2, 95% CI 1.9-5.4, p < 0.001) and a lower recanalization rate (17.5% vs. 26.1%, OR 0.3, 95% CI 0.2-0.6, p < 0.001) than stand-alone coiling at 6-month follow-up. In conclusion, SAC of large and wide-necked RIAs provided higher aneurysm occlusion and similar clinical outcome, when compared to stand-alone coiling.

Implantation of Large Diameter (5.5-6 mm) Derivo Embolization Devices for the Treatment of Cerebral Aneurysms

BACKGROUND

The efficacy of flow diverters is dependent upon robust wall apposition in the parent artery. Usage in large caliber cerebral vessels has therefore been limited as few implants with diameters > 5 mm exist. We present our initial experience in treating cerebral aneurysms using the 5.5 mm and 6 mm diameter implants of the Derivo embolization device (DED).

METHODS

Our prospectively maintained institutional database was reviewed to identify patients in whom a > 5 mm DED was implanted between November 2016 and February 2021. The primary efficacy outcome was complete or near-complete aneurysm occlusion at 6 months (O'Kelly-Marotta, OKM, C-D, adapted for magnetic resonance angiography). Safety outcomes included 30-day major morbidity defined as modified Rankin Score (mRS) 3-5, mortality, serious adverse events and procedural complications.

RESULTS

A total of 21 large diameter DEDs were deployed in 18 patients (age 59.5 ± 14.1 years), harboring 19 unruptured aneurysms. Of the aneurysms 14 (73.7%) were saccular in morphology (sac diameter 10.9 ± 5.5 mm, neck diameter 6.8 ± 3.1 mm), 3 (15.8%) aneurysms were dissecting, 1 (5.3%) iatrogenic pseudoaneurysm and 1 (5.3%) fusiform. Aneurysm locations were: ICA (internal carotid artery) (n = 17); (7 cavernous, 4 paraophthalmic, 2 paraclinoid, 1 petrous, 2 communicating, 1 cervical); vertebrobasilar (n = 2). Adjunct stenting to optimize proximal wall apposition was undertaken in 5 (27.8%) patients. At 6 months 75% of patients followed-up met the primary efficacy endpoint (OKM C-D). There were no serious adverse events, 30-day major morbidity (mRS 3-5) or mortality.

CONCLUSION

Implantation of large diameter (5.5 mm and 6 mm) DEDs into capacious cerebral vessels to treat a range of complex aneurysms is safe and technically feasible but may require adjunct stenting to optimize proximal wall apposition. Short-term efficacy of this device subset is comparable to previous DED and other flow diverter studies. Long-term follow-up and comparative studies are required for further assessment.

The Silk Vista Baby - The UK experience

BACKGROUND

The Silk Vista Baby (SVB) flow diverter (FDS) is the only FDS deliverable via a 0.017 inch microcatheter and is specifically designed for the distal vasculature. We sought to evaluate the safety and efficacy of the SVB.

MATERIALS AND METHODS

We performed a retrospective review to identify SVB cases at 4 tertiary neurosurgical centres within the U.K. Clinical, procedural, angiographic and follow-up data were collected.

RESULTS

We identified 60 patients (35 female, 58%) of average age 54 ± 10.5 (range 30-72) with 61 aneurysms, 50 (81.9%) located in the anterior circulation. The majority of the aneurysms treated were unruptured (46, 75.4%) and saccular (46, 75.4%). Dome size was 6.2 ± 6.2 mm (range 1-36mm) and parent vessel diameter was 2.3 ± 0.4 mm (range 1.2-3.3 mm).An average number of 1.07 devices were implanted. Coils or other devices were implanted in 14 aneurysms (23.3%). At last angiographic follow-up (n = 55), 7.5 ± 4.2 months post-procedure, 32 aneurysms (57.1%) were graded as RRC I, 7 (12.5%) RRC II, and 17 RRC III (30.4%).Clinical complications, excluding death, were seen in 4 patients (6.8%) including 1 delayed aneurysm rupture and 3 symptomatic ischaemic events. Only one patient had permanent morbidity (mRS 1). 3 patients died during follow-up (5.1%); 2 deaths were related to the aneurysms (3.4%) - one ruptured dissecting MCA aneurysm, and one giant partially thrombosed posterior circulation aneurysm. 93% of patients were mRS ≤ 2 at last follow-up.

CONCLUSION

The SVB has high rates of technical success and an acceptable safety profile. Distal aneurysms may occlude slower due to relative oversizing of the devices.

Long-term follow-up of the Derivo® Embolization Device (DED®) for intracranial aneurysms: the Italian Multicentric Registry

BACKGROUND

The flow-diverter devices (FDDs) safety and effectiveness have been demonstrated by large series and meta-analyses. Due to the high occlusion rates and the acceptable morbidity rates of FDDs, the indications for their use are continuously expanding. We presented our Italian multicentric experience using the second generation of DERIVO® Embolization Device (DED^®; Acandis, Pforzheim, Germany) to cure cerebral aneurysms, evaluating both middle and long-term safety and efficacy of this device.

METHODS

Between July 2016 and September 2017 we collected 109 consecutive aneurysms in 108 patients treated using DED^® during 109 endovascular procedures in 34 Italian centers (100/109 aneurysms were unruptured, 9/109 were ruptured). The collected data included patient demographics, aneurysm location and characteristics, baseline angiography, adverse event and serious adverse event information, morbidity and mortality rates, and pre- and post-treatment modified Rankin Scale scores. Midterm and long-term clinical, angiographic and cross-sectional CT/MR follow-up were recorded and collected until December 2018.

RESULTS

In 2/109 cases, DED^® placement was classified as technical failures. The overall mortality and morbidity rates were respectively 6.5% and 5.5%. Overall DERIVO® related mortality and morbidity rates were respectively 0% and 4.6% (5 out of 108 patients). Midterm neuroimaging follow-up showed the complete or nearly complete occlusion of the aneurysm in 90% cases, which became 93% at long-term follow-up. Aneurysmal sac shrinking was observed in 65% of assessable aneurysms.

CONCLUSIONS

Our multicentric experience using DED^® for endovascular treatment of unruptured and ruptured aneurysms showed a high safety and efficacy profile, substantially equivalent or better compared to the other FDDs.

Flow-diverter stents in the early management of acutely ruptured brain aneurysms: effective rebleeding protection with low thromboembolic complications

OBJECTIVE

Flow-diverter stents (FDSs) are not generally used for the management of acutely ruptured aneurysms with associated subarachnoid hemorrhage (SAH). Herein, the authors present their experience with FDSs in this scenario, focusing on the antiplatelet regimen, perioperative management, and outcome.

METHODS

The authors retrospectively reviewed their institutional database for the treatment and outcomes of all patients with acutely ruptured aneurysms and associated SAH from July 2010 to September 2018 who had received an FDS implant as stand-alone treatment within 4 days after diagnosis. The protocol with the use of flow diversion in these patients includes a low threshold for placement of external ventricular drains before stenting, followed by the administration of aspirin and clopidogrel with platelet testing before stent implantation. With this approach, the risk of hemorrhage and stent-related thrombus formation is limited. Demographic, clinical, technical, and imaging data were analyzed.

RESULTS

Overall, 76 patients (61% females, mean age 42.8 ± 11.3 years) met the inclusion criteria. FDS implantation was performed a median of 2 days after diagnosis. On average, 1.05 devices were used per procedure. There was no procedural mortality directly attributed to the endovascular intervention. Procedural device-related clinical complications were recorded in a total of 6 cases (7.9%) and resulted in permanent neurological morbidity in 2 cases (2.6%). There was complete immediate aneurysm occlusion in 11 patients (14.5%), and persistent aneurysm filling was seen in 65 patients (85.5%). Despite this, no patient presented with rebleeding from the target aneurysm. There was an excellent clinical outcome in 62 patients (81.6%), who had a 90-day modified Rankin Scale score of 0-2. Among the 71 survivors, total or near-total occlusion was observed in 64/67 patients (95.5%) with a 3- to 6-month angiographic follow-up and in all cases evaluated at 12 months. Five patients (6.6%) died during follow-up for reasons unrelated to the procedure or new hemorrhage.

CONCLUSIONS

Flow diversion is an effective therapeutic strategy for the management of select acutely ruptured aneurysms. Despite low rates of immediate aneurysm occlusion after FDS implantation, the device exerts an important protective effect. The authors' experience confirmed no aneurysm rerupture, high rates of delayed complete occlusion, and complication rates that compare favorably with the rates obtained using other techniques.

Outcome of Flow Diverters with Surface Modifications in Treatment of Cerebral Aneurysms: Systematic Review and Meta-analysis

BACKGROUND

Newer flow diverters are enhanced with antithrombogenic surface modifications like the Pipeline Embolization Device with Shield Technology and the Derivo Embolization Device and are purported to facilitate deployment and reduce ischemic events.

PURPOSE

Our aim was to review the safety and efficacy of surface-modified flow diverters in treating patients with cerebral aneurysms.

DATA SOURCES

We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review and meta-analysis covering 3 major data bases and gray literature between 2014 and 2019.

STUDY SELECTION

Two reviewers independently reviewed human studies of surface-modified flow diverters for eligibility based on predetermined criteria.

DATA ANALYSIS

The random effects model and Freeman-Tukey arcsine transformation were used to pool efficacy outcomes (technical success, aneurysm occlusion at 6 and 12 months) and safety outcomes (mortality, morbidity, all ischemia, and serious ischemia). Subgroup analysis was performed to compare outcomes between 2 different flow diverters.

DATA SYNTHESIS

Eight single-arm case series involving 911 patients and 1060 aneurysms were included. The median follow-up was 8.24 months. Pooled estimate for technical success was 99.6%, while the aneurysm occlusion at 6 and 12 months were 80.5%, and 85.6%, respectively. Pooled estimates for mortality, morbidity, total ischemia, and serious ischemia rates were 0.7%, 6.0%, 6.7%, and 1.8%, respectively. Most studies were of good quality, and no significant heterogeneity was observed.

LIMITATIONS

Limitations include a retrospective, observational design in some studies; heterogeneous and underreported antiplatelet therapy; and potential performance and ecologic bias.

CONCLUSIONS

Early-to-midterm safety and efficacy for surface-modified flow diverters appear comparable with older devices, especially for small, unruptured anterior circulation aneurysms. Long-term clinical data are required to further corroborate these results.

Overview of Different Flow Diverters and Flow Dynamics

Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes. To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable. Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient. In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.

Comaneci-Assisted Coiling as a Treatment Option for Acutely Ruptured Wide Neck Cerebral Aneurysm: Case Series of 118 Patients

BACKGROUND

Wide-necked cerebral aneurysms in the setting of acute subarachnoid hemorrhage (SAH) remain difficult to treat with endovascular methods despite recent progress in the neuroendovascular field.

OBJECTIVE

To evaluate the effectiveness and safety of the Comaneci device (Rapid Medical, Israel) in endovascular coil embolization of acutely ruptured, wide-necked sidewall, or bifurcation cerebral aneurysms.

METHODS

We retrospectively reviewed 45 anterior communicating artery, 24 internal carotid artery, 21 middle cerebral artery bifurcation, 15 anterior cerebral artery, and 13 posterior circulation aneurysms, which were treated using Comaneci-assisted coil embolization from August 2017 to January 2019. We evaluated procedural complications, clinical outcomes, and mid-term angiographic follow-up. Immediate and 90 d-clinical outcome and radiological follow-up were obtained in all patients.

RESULTS

Comaneci-assisted coil embolization was performed in 118 acutely ruptured aneurysms. The technique was carried out successfully in all cases. Simultaneous application of 2 separated Comaneci devices was performed in 8/118 cases (6.77%). Periprocedural thromboembolic complications related to the device were seen in 7/118 cases (5.93%) and severe vasospasm of the parent artery after manipulation of the Comaneci device occurred in 5/118 cases (4.2%). The procedural-related morbidity rate was 2.54%, and there was no procedural related mortality. Among the available survivors, angiographic follow-ups were obtained at 3 and 6 mo, and complete aneurysmal obliteration was confirmed in 81/112 (72.3%) and 75/112 (66.9%) cases, respectively. Mid-term follow-up reviewed total recanalization rate of 14.28%.

CONCLUSION

Comaneci-assisted embolization of wide-necked intracranial aneurysms in patients presenting with acute SAH is associated with high procedural safety and adequate occlusion rates. Furthermore, dual antiplatelet therapy can be safely avoided in this patient group.

Comparative Analysis of the Pipeline and the Derivo Flow Diverters for the Treatment of Unruptured Intracranial Aneurysms-A Multicentric Study

OBJECTIVE

Flow diversion represents a safe and efficient technique for the endovascular treatment of complex intracranial aneurysms. This study compares 2 competing flow diverters, the Pipeline embolization device (PED) and the Derivo Embolization Device (DED) regarding technical aspects, clinical outcome, and angiographic results.

METHODS

A total of 111 patients with unruptured aneurysms were treated with the PED (n = 62) or the DED (n = 49) between 2011 and 2019. Procedural specifics, complication rates, functional outcome, and aneurysm occlusion were evaluated retrospectively.

RESULTS

Flow-diverter implantation was technically successful in all patients. There were no significant differences regarding baseline characteristics, adjunctive coiling, and fluoroscopy time. Multiple devices were more often used in the PED group (35.6%) than in the DED group (4.1%, P < 0.001). Procedural adverse events occurred in 4 cases of each group (PED: 5.5%, DED: 8.2%, P = 0.713), including 3 thromboembolic events and 1 hemorrhagic event per group. Morbidity rates were similar between the 2 groups (PED: 2.7%, DED: 4.1%, P = 1.0). There was no procedural mortality. At 6-month follow-up, complete or near-complete occlusion (O'Kelly-Marotta scale C+D) was achieved in 79.0% (49/62) after PED implantation and 80.0% (32/40) after DED implantation (P = 0.354).

CONCLUSIONS

In regard to complication rates, functional outcome, and aneurysm occlusion, no significant differences were found between the PED and DED collective.

Review of current intracranial aneurysm flow diversion technology and clinical use

Endovascular treatment of intracranial aneurysms (IAs) has evolved considerably over the past decades. The technological advances have been driven by the experience that coils fail to completely exclude all IAs from the blood circulation, the need to treat the diseased parent vessel segment leading to the aneurysm formation, and expansion of endovascular therapy to treat more complex IAs. Stents were initially developed to support the placement of coils inside wide neck aneurysms. However, early work on stent-like tubular braided structure led to a more sophisticated construct that then later was coined as a flow diverter (FD) and found its way into clinical application. Although FDs were initially used to treat wide-neck large and giant internal carotid artery aneurysms only amenable to surgical trap with or without a bypass or endovascular vessel sacrifice, its use in other types of IAs and cerebrovascular pathology promptly followed. Lately, we have witnessed an explosion in the application of FDs and subsequently their modifications leading to their ubiquitous use in endovascular therapy. In this review we aim to compile the available FD technology, evaluate the devices' peculiarities from the authors' perspective, and analyze the current literature to support initial and expanded indications, recognizing that this may be outdated soon.

Delayed hospital admission of patients with aneurysmal subarachnoid hemorrhage: clinical presentation, treatment strategies, and outcome

OBJECTIVE

Timely aneurysm occlusion and neurointensive care treatment are key principles in the management of aneurysmal subarachnoid hemorrhage (aSAH) to prevent secondary brain injury. Patients with early (EHA) and delayed hospital admission (DHA) were compared in terms of clinical presentation, treatment strategies, aSAH-related complications, and outcome.

METHODS

In this retrospective study, consecutive aSAH patients were treated at a single neurovascular center between 2009 and 2019. Propensity score matching was performed to account for divergent baseline characteristics.

RESULTS

Among 509 included patients, 55 were admitted more than 48 hours after ictus (DHA group). DHA patients were significantly younger (52 ± 11 vs 56 ± 14 years, p = 0.03) and had lower World Federation of Neurosurgical Societies scores (p < 0.01) than EHA patients. In 54.5% of the cases, DHA patients presented with neurological deterioration or aggravated symptoms. Propensity score matching revealed a higher vasospastic infarction rate in the DHA group (41.5%) than in the EHA group (22.6%) (p = 0.04). A similar portion of patients in both groups achieved favorable outcome at midterm follow-up (77.3% vs 73.6%, p = 0.87). DHA patients (62.3%) received conventional coiling more often than EHA patients (41.5%) (p = 0.03).

CONCLUSIONS

DHA patients are at an increased risk of cerebral infarction. Nevertheless, state-of-the-art neurointensive care treatment can result in a good clinical outcome.

Ruptured Basilar Artery Dissection Diagnosed Using Magnetic Resonance Vessel Wall Imaging and Treated with Coil Embolization with Overlapping LVIS Stents: A Case Report

The diagnosis and treatment of patients with ruptured basilar artery dissection (rBAD) are often difficult. We present a case of rBAD diagnosed with magnetic resonance vessel wall imaging (MR-VWI) and treated with coil embolization with overlapping low-profile visualized intraluminal support (LVIS) stents. The case is of a 49-year-old woman with subarachnoid hemorrhage. digital subtraction angiography (DSA) showed irregularity in an anterior wall of the middle portion of the basilar artery, indicating the presence of a false lumen. MR-VWI showed local enhancement in an arterial wall, which was consistent with the wall irregularity observed in DSA. Overlapping stents (two LVIS stents) was performed in the basilar artery and coils were placed in the false lumen. The false lumen was completely thrombosed, and anterograde blood flow of the basilar artery was preserved. Dual antiplatelet therapy was administered, and the patient underwent an uneventful postoperative course. DSA performed 6 months later showed a white-collar sign. MR-VWI has attracted attention as a useful modality for detecting a ruptured lesion in patients with subarachnoid hemorrhage. This is the first report, to the best of our knowledge, describing the practical use of MR-VWI for rBAD. MR-VWI is suggested to improve diagnostic accuracy for rBAD. There are no established treatments for rBAD; reconstructive endovascular treatments comprising stent placement and coil embolization of a false lumen are promising. The LVIS stent has a braided design and high metal coverage ratio and is considered to be reasonable for use in rBAD. Coil embolization of a false lumen with overlapping LVIS stents may be effective for rBAD.

Radiation dose and fluoroscopy time of modern endovascular treatment techniques in patients with saccular unruptured intracranial aneurysms

Objectives

Modern endovascular treatment of unruptured intracranial aneurysms (UIAs) demands for observance of diagnostic reference levels (DRLs). The national DRL (250 Gy cm²) is only defined for coiling. We provide dosimetric data for the following procedures: coiling, flow diverter (FD), Woven EndoBridge (WEB), combined techniques.

Methods

A retrospective single-centre study of saccular UIAs treated between 2015 and 2019. Regarding dosimetric analysis, the parameters dose area product (DAP) and fluoroscopy time were investigated for the following variables: endovascular technique, aneurysm location, DSA protocol, aneurysm size, and patient age.

Results

Eighty-seven patients (59 females, mean age 54 years) were included. Total mean and median DAP (Gy cm²) were 119 ± 73 (89–149) and 94 (73; 130) for coiling, 128 ± 53 (106–151) and 134 (80; 176) for FD, 128 ± 56 (102–153) and 118 (90; 176) for WEB, and 165 ± 102 (110–219) and 131 (98; 209) for combined techniques (p > .05). Regarding the aneurysm location, neither DAP nor fluoroscopy time was significantly different (p > .05). The lowest and highest fluoroscopy times were recorded for WEB and combined techniques, respectively (median 26 and 94 min; p < .001). A low-dose protocol yielded a 43% reduction of DAP (p < .001). Significantly positive correlations were found between DAP and both aneurysm size (r = .320, p = .003) and patient age (r = .214, p = .046).

Conclusions

This UIA study establishes novel local DRLs for modern endovascular techniques such as FD and WEB. A low-dose protocol yielded a significant reduction of radiation dose.

Key Points

• This paper establishes local diagnostic reference levels for modern endovascular treatment techniques of unruptured intracranial aneurysms, including flow diverter stenting and Woven EndoBridge device.

• Dose area product was not significantly different between endovascular techniques and aneurysm locations, but associated with aneurysm size and patient age.

• A low-dose protocol yielded a significant reduction of dose area product and is particularly useful when applying materials with a high radiopacity (e.g. platinum coils).

Retreatment strategies for recurrent and residual aneurysms after treatment with flow-diverter devices

PURPOSE

The management of residual or persistent intracranial aneurysms after flow-diversion therapy is not well defined in the literature. In this multicentric study, we report clinical and angiographic outcomes of 11 patients that underwent retreatment for 12 aneurysms initially treated with flow-diverter stents.

METHODS

The median patient age was 53 years. Aneurysms (median size, 7.3 mm) were located at the internal carotid artery in 9 cases, and at the posterior circulation in 3. Treatment strategies, complications, and angiographic outcome were retrospectively assessed.

RESULTS

Retreatment was feasible in all cases and performed by overlapping flow-diverter implantation. Overall, 12 side vessels were covered during retreatment, whereof 10 (83.3%) remained patent until mid-term follow-up. There were no further technical or symptomatic complications and no treatment-related morbidity. Angiographic follow-up (median, 17 months) showed improved aneurysm occlusion in all patients. Complete or near-complete aneurysm occlusion was achieved in 11 aneurysms (91.7%).

CONCLUSION

Required retreatment after failed flow-diversion therapy can be performed with adequate safety and efficacy by placement of additional flow-diverter stents.

Low-Profile Laser-Cut Stents for Endovascular Treatment of Intracranial Aneurysms : Incidence, Clinical Presentation and Risk Factors of Thromboembolic Events

PURPOSE

Low-profile intracranial stents are characterized by a miniaturized design that enables deployment via a 0.0165″ or 0.017″ internal diameter microcatheter, which is typically intended for coil delivery. This study analyzed the incidence, clinical relevance and risk factors of thromboembolic events (TEE) occurring during low-profile stent-assisted coiling of intracranial aneurysms.

METHODS

This was a retrospective, multicenter analysis of consecutive patients who underwent stent-assisted aneurysm coiling (SAC) with the laser-cut Acandis Acclino and Neuroform Atlas stents. The study evaluated the incidence of symptomatic and asymptomatic TEEs and the impact on functional outcome. Risk factors for TEEs were determined by univariate and bivariate logistic regression analyses.

RESULTS

Among 131 procedures (mean patient age 56.5 ± 12.8 years, mean aneurysm size: 6.7 ± 3.9 mm) TEEs occurred in 14 cases (10.7%) of which 2 patients (1.5%) developed ischemic stroke, while the remaining TEEs remained asymptomatic. Multivariate analysis revealed Y‑stenting as potential risk factor for TEEs (odds ratio: 3.9, 95% confidence interval: 1.0-16.5; p = 0.08).

CONCLUSION

The use of SAC with low-profile intracranial stents is associated with a favorable safety profile; however, Y‑stenting may carry an increased risk of TEEs, which needs to be considered during treatment planning.

Expanding Indications for Flow Diverters: Ruptured Aneurysms, Blister Aneurysms, and Dissecting Aneurysms

BACKGROUND

The safety and efficacy of flow diversion (FD) in the treatment of cerebral aneurysms have been reported by many studies. FD has enabled the treatment of complex aneurysms and aneurysms that were previously untreatable by conventional means. It has achieved high rates of obliteration with essentially no recanalization, and its indications have continued to expand, now including ruptured aneurysms, blister aneurysms, and dissecting aneurysms.

OBJECTIVE

To provide a review on the outcomes of studies covering the use of FD in the settings of ruptured, blister, and dissecting aneurysms. In addition, to discuss dual antiplatelet therapy (DAPT) used in preparation for FD deployment in these scenarios, including associated complications with DAPT use in the acute rupture setting.

METHODS

References for this topical review were identified by PubMed searches between January 2000 and January 2019. The search terms “aneurysm”, “flow diverter”, “stent”, “pipeline”, “ruptured”, “blister”, and “dissecting aneurysms” were used.

RESULTS

FD carries a higher complication rate in the acute rupture setting than for unruptured aneurysms. Patient selection is of paramount importance for achieving good functional and angiographic outcomes. DAPT still remains challenging, especially in ruptured aneurysms. Advancements in surface modification of flow diverters can reduce the risk of thromboembolism and perhaps lead to a safer antiplatelet regimen.

CONCLUSION

In summary, FD shows promise to be an effective treatment for ruptured, blister, and dissecting aneurysms.

Derivo Embolization Device for the Treatment of Intracranial Aneurysms

Background and Purpose—

Flow diverter technology improvements are necessary to provide safe and good results and enable the treatment of a larger variety of aneurysms. We report a nationwide experience with the Derivo Embolization Device in the treatment of intracranial aneurysms.

Methods—

BRAIDED (Brazilian Registry of Aneurysms Assigned to Intervention With the Derivo Embolization Device) is a multicenter, prospective, interventional, single-arm trial of the Derivo Embolization Device for the treatment of intracranial aneurysms. The primary effectiveness end point was total aneurysm occlusion at 6- and 12-month angiographies. The secondary safety end point was the absence of serious adverse events during follow-up. Univariable and multivariable logistic regression was performed to identify predictors of aneurysm persistence, periprocedural complications, and adverse events during follow-up.

Results—

Between December 2016 and October 2018, 146 patients harboring 183 intracranial aneurysms were treated in 151 interventions at 7 centers. Derivo Embolization Device placement was technically successful in all patients. Most aneurysms (86.9%) were located at the internal carotid artery, and the mean diameter was 6.7 mm. At 6 months, 113 of 140 (80.7%) aneurysms met the study’s primary end point, and 74 of 83 (89.2%) met the study’s primary end point at 12 months. Saccular morphology of the aneurysm (odds ratio, 5.66; 95% CI, 1.01–31.77) and the presence of a branch arising from the sac (odds ratio, 6.36; 95% CI, 2.11–22.36) predicted persistence. A long duration of follow-up (odds ratio, 0.86; 95% CI, 0.78–0.95) predicted total occlusion. Of the 146 enrolled patients, 138 (94.5%) were treated without serious adverse events during follow-up. In the multivariable analysis, aneurysms located at a sidewall were less likely to experience these events than those located at bifurcations (odds ratio, 0.07; 95% CI, 0.01–0.51).

Conclusions—

The Derivo Embolization Device is a safe and effective treatment for intracranial aneurysms.

Clinical Trial Registration—

URL: http://plataformabrasil.saude.gov.br/login.jsf . Unique identifier: CAAE 77089717.7.1001.5125.

The p64 Flow Diverter-Mid-term and Long-term Results from a Single Center

BACKGROUND AND PURPOSE

The p64 is a flow modulation device designed to be used in endovascular treatment of intracranial aneurysms. There is limited data on the long-term effectiveness of the device. This study sought to determine the safety and long-term efficacy of this device.

METHODS

A retrospective review of a prospectively maintained database was performed to identify all patients treated with a p64 between March 2015 and November 2018 at University Hospital St. Ivan Rilski. Anatomical features, intraprocedural complications, clinical, and angiographic outcomes were also taken into account and reviewed.

RESULTS

A total of 72 patients with 72 aneurysms who met the inclusion criteria were identified. Device placement was successful in all patients. Follow-up angiographic imaging at 6 months showed complete occlusion (O'Kelly-Marotta scale [OKM] D) in 55 (76.3%) patients, subtotal aneurysmal filling (OKM B) in 10 (13.8%) patients, and neck remnant (OKM C) in 7 (9.7%) patients. Catheter angiography at 12 months was available for 70 patients (97.2%) and of these patients 91.4% of the aneurysms were completely occluded (OKM D) (64/72). Delayed angiography at 24 months was available for 68 patients (94.4%) and of these 98.5% (67/68) had completely occluded aneurysms. A 36-month angiography was available for 61 patients (84.4%) by which point all aneurysms had been completely occluded (100%). Permanent morbidity due to delayed aneurysmal rupture occurred in one patient (1.38%). The mortality rate was 0%. Self-limiting mild intimal hyperplasia was seen in 2 patients (2.72%).

CONCLUSION

Treatment of intracranial aneurysms with a p64 flow modulation device is safe and effective with a high success rate and only infrequent complications.

Endovascular treatment of intracranial 'blister' and dissecting aneurysms

INTRODUCTION

Blister and dissecting aneurysms may have a different pathological background but they are commonly defined by instability of the vessel wall and bear a high risk of fatal rupture and rerupture. Lack of aneurysm sack makes treatment challenging.

PURPOSE

The purpose of this study was to assess the safety and feasibility of endovascular treatment of intracranial blister and dissecting aneurysms.

METHODS

We retrospectively analysed all patients with ruptured and unruptured blister and dissecting aneurysms treated endovascularly between 2004-2018. Procedural details, complications, morbidity/mortality, clinical favourable outcome (modified Rankin Scale ≤2) and aneurysm occlusion rates were assessed.

RESULTS

Thirty-four patients with endovascular treatment of 35 aneurysms (26 dissecting aneurysms and 9 blister aneurysms) were included. Five aneurysms were treated by parent vessel occlusion, and 30 aneurysms were treated by vessel reconstruction using stent monotherapy (n = 9), stent-assisted coiling (n = 7), flow diverting stents (n = 13) and coiling + Onyx embolization (n = 1). No aneurysm rebleeding and no procedure-related major complications or deaths occurred. There were five deaths in consequence of initial subarachnoid haemorrhage. Complete occlusion (79.2%) was detected in 19/24 aneurysms available for angiographic follow-up, and aneurysm recurrence in 2/24 (8.3%). The modified Rankin Scale ≤2 rate at mean follow-up of 15.1 months was 64.7%.

CONCLUSION

Treatment of blister and dissecting aneurysms developed from coil embolization to flow diversion with multiple stents to the usage of flow diverting stents. Results using modern flow diverting stents encourage us to effectively treat this aneurysm entity endovascularly by vessel reconstruction. Therefore, we recommend preference of vessel reconstructive techniques to parent vessel occlusion.

Thrombogenicity assessment of Pipeline, Pipeline Shield, Derivo and P64 flow diverters in an in vitro pulsatile flow human blood loop model

Flow diversion is a disruptive technology for the treatment of intracranial aneurysms. However, these intraluminal devices pose a risk for thromboembolic complications despite dual antiplatelet therapy. We report the thrombogenic potential of the following flow diversion devices measured experimentally in a novel human blood in-vitro pulsatile flow loop model: Pipeline™ Flex Embolization Device (Pipeline), Pipeline™ Flex Embolization Device with Shield Technology™ (Pipeline Shield), Derivo Embolization Device (Derivo), and P64 Flow Modulation Device (P64). Thrombin generation (Mean ± SD; μg/mL) was measured as: Derivo (28 ± 11), P64 (21 ± 4.5), Pipeline (21 ± 6.2), Pipeline Shield (0.6 ± 0.1) and Negative Control (1.5 ± 1.1). Platelet activation (IU/μL) was measured as: Derivo (4.9 ± 0.7), P64 (5.2 ± 0.7), Pipeline (5.5 ± 0.4), Pipeline Shield (0.3 ± 0.1), and Negative Control (0.9 ± 0.7). We found that Pipeline Shield had significantly lower platelet activation and thrombin generation than the other devices tested (p < .05) and this was comparable to the Negative Control (no device, p > .05). High resolution scanning electron microscopy performed on the intraluminal and cross-sectional surfaces of each device showed the lowest accumulation of platelets and fibrin on Pipeline Shield relative to Derivo, P64, and Pipeline. Derivo and P64 also had higher thrombus accumulation at the flared ends. Pipeline device with Phosphorylcholine surface treatment (Pipeline Shield) could mitigate device material related thromboembolic complications.