The Derivo Embolization Device, a Second-Generation Flow Diverter for the Treatment of Intracranial Aneurysms, Evaluated in an Elastase-Induced Aneurysm Model

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.

Derivo embolization device for intracranial aneurysms: a Spanish multicenter retrospective study

BACKGROUND

Flow diverters have emerged in recent years as a safe and effective treatment for intracranial aneurysms, with expanding indications. The Derivo embolization device (DED) is a second-generation flow diverter with a surface finish that may reduce thrombogenicity. We report our multicenter experience evaluating its safety and efficacy.

METHODS

We retrospectively analyzed all patients treated with the DED in eight centers in Spain between 2016 and 2020. Demographics, clinical data, procedural complications, morbidity and aneurysm occlusion rates were collected.

RESULTS

A total of 209 patients with 250 aneurysms were treated (77.5% women). The majority of aneurysms were located in the internal carotid artery (86.8%) and most (69.2%) were small (<10 mm) with a median maximum diameter of 5.85 mm and median neck size of 4 mm. DED deployment was successful in all cases, despite two malfunctioning devices (1%). Major complications occurred in nine patients (4.3%), while mild neurologic clinical events were registered in 23 (11%); four patients died (1.9%). A total of 194 aneurysms had an angiographic follow-up at 6 months and showed complete aneurysm occlusion in 75% of cases. Twelve-month follow-up was available for 112 of the treated aneurysms, with a total occlusion rate of 83%.

CONCLUSION

The DED is a second-generation surface-modified flow diverter that presents an option for treatment of intracranial aneurysms with comparable safety and efficacy to other available flow diverter devices. Nonetheless, risks are not negligible, and must be balanced against the natural history risk of cerebral aneurysms, considering the tendency to widen indications for treatment of smaller and less complex lesions in day-to-day use.

Endovascular treatment of unruptured intracranial aneurysms with flow diverters: A retrospective long-term single center analysis

PURPOSE

The introduction of flow diverters (FDs) in 2007 greatly enhanced the treatment of intracranial aneurysms. Here, we present our long-term clinical experience in treating unruptured intracranial aneurysms with FDs.

METHODS

107 patients with unruptured aneurysms and treated with an FD between 2010 and 2019 were retrospectively reviewed. Aneurysm occlusion, procedural complications, and clinical outcome were evaluated.

RESULTS

Angiographic follow-up was available for 93 patients with a mean long-term follow-up time of 28.4 ± 21.6 months. Additional coiling was performed in 15.1% of patients (n = 14). Adequate aneurysm occlusion (Kamran grades 3 and 4) at long-term follow-up was achieved in 94.6% of patients (n = 88). 3.2% (n = 3) required endovascular retreatment since the last follow-up showed a lack of aneurysm occlusion (Kamran grade 0) due to a foreshortening of the FD. Incomplete opening of the FD and parent vessel occlusion was seen in 1.1% (n = 1) and 3.2% (n = 3) of patients, respectively. In-stent stenosis was observed in 57% (n = 53) of cases at short-term follow-up and 22.6% (n = 21) at long-term, which were moderate and asymptomatic overall. In-stent stenosis decreased significantly between short- and long-term follow-ups (31.4 ± 17.0% vs 9.7 ± 13.6%, respectively; p ≤ 0.001). Thromboembolic and hemorrhagic events occurred in 7.5% (n = 7) and 1.1% (n = 1) of patients, respectively. Good clinical outcome (modified Rankin scale: 0-2) was obtained in 97.8% (n = 91) leading to an overall treatment-related morbidity of 2.2% (n = 2). There was no procedural mortality.

CONCLUSION

Our study shows that FD treatment of unruptured intracranial aneurysms is effective and safe with high occlusion rates and low rates of permanent morbidity at long-term follow-up.

CFD to Quantify Idealized Intra-Aneurysmal Blood Flow in Response to Regular and Flow Diverter Stent Treatment

Cerebral aneurysms are pathological dilatations of the vessels supplying the brain. They carry a certain risk of rupture, which in turn, results in a high risk of mortality and morbidity. Flow diverters (FDs) are high-density meshed stents which are implanted in the vessel segment harboring an intracranial aneurysm to cover the entrance of the aneurysm, thus reducing the blood flow into the aneurysm, promoting thrombosis formation and stable occlusion, which prevents rupture or growth of the aneurysm. In the present study, the blood flow in an idealized aneurysm, treated with an FD stent and a regular stent (RS), were modeled and analyzed considering their design, surface area porosity, and flow reduction to investigate the quantitative and qualitative effect of the stent on intra-aneurysmal hemodynamics. CFD simulations were conducted before and after treatment. Significant reductions were observed for most hemodynamic variables with the use of stents, during both the peak systolic and late diastolic cardiac cycles. FD reduces the intra-aneurysmal wall shear stress (WSS), inflow, and aneurysmal flow velocity, and increases the turnover time when compared to the RS; therefore, the possibility of aneurysm thrombotic occlusion is likely to increase, reducing the risk of rupture in cerebral aneurysms.

Disturbed flow's impact on cellular changes indicative of vascular aneurysm initiation, expansion, and rupture: A pathological and methodological review

Aneurysms are malformations within the arterial vasculature brought on by the structural breakdown of the microarchitecture of the vessel wall, with aneurysms posing serious health risks in the event of their rupture. Blood flow within vessels is generally laminar with high, unidirectional wall shear stressors that modulate vascular endothelial cell functionality and regulate vascular smooth muscle cells. However, altered vascular geometry induced by bifurcations, significant curvature, stenosis, or clinical interventions can alter the flow, generating low stressor disturbed flow patterns. Disturbed flow is associated with altered cellular morphology, upregulated expression of proteins modulating inflammation, decreased regulation of vascular permeability, degraded extracellular matrix, and heightened cellular apoptosis. The understanding of the effects disturbed flow has on the cellular cascades which initiate aneurysms and promote their subsequent growth can further elucidate the nature of this complex pathology. This review summarizes the current knowledge about the disturbed flow and its relation to aneurysm pathology, the methods used to investigate these relations, as well as how such knowledge has impacted clinical treatment methodologies. This information can contribute to the understanding of the development, growth, and rupture of aneurysms and help develop novel research and aneurysmal treatment techniques.

REtrospective Multicenter INdian Study of Derivo Embolization Device (REMIND): Periprocedural Safety

Purpose

The treatment of aneurysms with characteristics such as complex morphology, fusiform, blister-like, wide neck, or large size has been revolutionized with the introduction of flow diverters. Though flow diverters have several advantages over coiling, they also have certain important disadvantages such as the lack of immediate protection against rupture, the risk of ischemic stroke, the need for antiplatelet therapy, and long latency for complete effect. The Derivo Embolization Device (DED) is a second-generation self-expanding device that is claimed to be less thrombogenic than conventional devices. We retrospectively evaluated the periprocedural safety and risks associated with the DED across 5 centers in India.

Materials and Methods

This is a multicentric, retrospective, observational study of DED, conducted at 5 high volume endovascular therapy centers in India from May 2018 to June 2020. Periprocedural demographic, clinical, and angiographic data were collected from a retrospective review of patient charts.

Results

A total of 96 patients, including 56 (58.3%) females, aged between 16–80 years (60±12.7 years) harboring 106 aneurysms were studied. Seven (7.3%) were noted to harbor multiple aneurysms: 6 had 3 aneurysms each, while 1 patient had 5 aneurysms. The following aneurysm characteristics were noted: average size, 9.8±8.2 mm; average neck size, 6.9±8.5 mm; wide-necked (>4 mm), 63 (59.4%); giant (>25 mm), 8 (7.5%); and anterior circulation location, 98 (92.5%). Eighteen (17%) of these were ruptured. Additional balloon angioplasty was performed in 5 (5.2%) patients. Intraprocedural problems were encountered in 3 (3.1%), of which only 1 had clinical implications, the device fish-mouthing with stent thrombosis resulting in a malignant middle cerebral artery territory infarction. The modified Rankin scale at 3 months was worse in 1 patient.

Conclusion

DED is a newer generation flow diverter stent with a low periprocedural complication rate.

A realistic way to investigate the design, and mechanical properties of flow diverter stents

PURPOSE

Braided flow diverters (FD) are highly sophisticated, delicate, and intricate mechanical devices used to treat intracranial aneurysms. Testing such devices in vitro, however, remains an unsolved challenge. Here, we evaluate methods to measure flow, design and mechanical properties in vitro.

METHODS

Flow properties, cell porosity, pore density, and cell area were evaluated under geometrically realistic conditions by placing FDs in patient-derived, 3D-printed models of human vasculature. 4D flow MRI was used to measure fluid dynamics. Laser microscopy was used to measure the design properties of the FDs. New methods were developed to investigate the bending, circumferential, and longitudinal radial force of the FDs continuously over varying diameters.

RESULTS

The placement and flow properties of the FD in the vasculature models were successfully measured by MRI, although artifacts occurred. Likewise, the porosity, pore density, and cell area were successfully measured inside of the models using a laser microscope. The newly developed mechanical methods allowed to measure the indicated forces - to our knowledge for the first time - continuously.

CONCLUSION

Modern and specifically tailored techniques, some of which were presented here for the first time, allow detailed insights into the flow, design, and mechanical properties of braided flow diverter stents.

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.

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.

[Treatment of intracranial aneurysms with flow diverters]

CLINICAL ISSUE

The clinical picture of a subarachnoid haemorrhage (SAH) is associated with a high morbidity and mortality, due to the associated complications. Therefore, both unruptured and ruptured aneurysms are to be treated based on an individual and interdisciplinary treatment concept. Several endovascular procedures are already available for the treatment of intracranial aneurysms. A more recent concept is the treatment with vessel-reconstructive stents so-called flow diverters.

PRACTICAL RECOMMENDATIONS

Due to the continuous development and revision of flow diverters, the initial complication rates have been significantly reduced, which now effectively and efficiently justifies their clinical use. After careful patient selection and risk-benefit assessment, the implantation of a flow diverter can also be considered for the treatment of ruptured aneurysms and is often the only therapy option in such situations.

Derivo embolization device in the treatment of unruptured intracranial aneurysms: a prospective multicenter study

Background

Flow diverters (FD) are used regularly for the endovascular treatment of unruptured intracranial aneurysms. We aimed to assess the safety and effectiveness of the Derivo embolization device (DED) with respect to long-term clinical and angiographic outcomes.

Methods

A prospective multicenter trial was conducted at 12 centers. Patients presenting with modified Rankin Score (mRS) of 0–1, treated for unruptured intracranial aneurysms with DED were eligible. Primary endpoint was the mRS assessed at 18 months with major morbidity defined as mRS 3–5. Satisfactory angiographic occlusion was defined as 3+4 on the Kamran scale.

Results

Between July 2014 and February 2018, 119 patients were enrolled. Twenty-three patients were excluded. Ninety-six patients, 71 (74%) female, mean age 54±12.0 years, were included in the analysis. Mean aneurysm size was 14.2±16.9 mm. The mean number of devices implanted per patient was 1.2 (range 1–3). Clinical follow-up at 18 months was available in 90 (94%) patients, resulting in a mean follow-up period of 14.8±5.2 months. At last available follow-up of 96 enrolled patients, 91 (95%) remained mRS 0–1. The major morbidity rate (mRS 3–5) was 3.1% (3/96), major stroke rate was 4.2% (4/96), and mortality was 0%. Follow-up angiographies were available in 89 (93%) patients at a median of 12.4±5.84 months with a core laboratory adjudicated satisfactory aneurysm occlusion in 89% (79/89).

Conclusion

Our results suggest that DED is a safe and effective treatment for unruptured aneurysms with high rates of satisfactory occlusion and comparably low rates of permanent neurological morbidity and mortality.

Trial registration

DRKS00006103

Stent-assisted coiling of broad-necked intracranial aneurysms with a new braided microstent (Accero): procedural results and long-term follow-up

Intracranial stents have expanded endovascular therapy options for intracranial aneurysms. The braided Accero stent is available for clinical use since May 2015. To date, no clinical reports on the stent are available. Purpose of this study was the evaluation of the safety and efficacy of the Accero stent in stent-assisted coiling. All patients, in whom implantation of the stent was performed, were included. Primary endpoints were good clinical outcome (mRS ≤ 2) and aneurysm occlusion grades 1 and 2 (Raymond Roy Occlusion Classification). Secondary endpoints were procedural and device-related complications with permanent disability or death, complications in the course, and the recanalization rate. Between September 2015 and August 2018, thirty-four aneurysms were treated with stent-assisted coiling using the Accero. Sixteen aneurysms were untreated, four of these were ruptured. Mild neurological complications occurred in 2/34 (5.9%) treatments. Two stent occlusions occurred during follow-up. No patient had a poor procedure- or device-related outcome. After an average of 15 months of follow-up, 28/30 aneurysms were completely or near-completely occluded. The Accero stent proved to be safe and effective in the treatment of broad-based intracranial aneurysms. The complication rate and the rate of successful aneurysm occlusions are similar to those of other stents.

Future Directions of Flow Diverter Therapy

The treatment of intracranial aneurysms has undergone a few very significant paradigm shifts in its history. Needless to say, microsurgery and surgical clipping served as the initial basis for successful treatment of these lesions. The pursuit of endovascular therapy subsequently arose from the desire to reduce the invasiveness of therapy. While the first breakthrough arose with Guido Guglielmi's invention of the detachable platinum coil, commercialized flow diverter therapy represents a disruptive therapy with a completely different paradigm for aneurysmal obliteration. This has not only altered the distribution of aneurysmal management strategies, but also opened the gateway to the treatment of previously inoperable lesions. With the basic flow diverter stent technology now considered an integral part of the neurointerventional armamentarium, we now consider what may lay in the future - including potential directions for research with regards to case selection; the location and type of aneurysms which may become routinely treatable; and modifications to the flow diverter, which may increase its utility and safety in terms of size, structural design, and surface modifications.

Low-Profile Intra-Aneurysmal Flow Disruptor WEB 17 versus WEB Predecessor Systems for Treatment of Small Intracranial Aneurysms: Comparative Analysis of Procedural Safety and Feasibility

BACKGROUND AND PURPOSE

The Woven EndoBridge 17 has recently been introduced to the market for facilitated endovascular treatment of small bifurcation aneurysms (≤7 mm) with low-profile microcatheters. We compared the Woven EndoBridge 17 with its predecessor versions in terms of procedural safety and feasibility.

MATERIALS AND METHODS

This was a multicenter review of aneurysms ranging from 3 to 7 mm treated with the Woven EndoBridge between 2011 and 2019. Aneurysm characteristics, procedural parameters, and complications were retrospectively compared between treatment with the Woven EndoBridge 17 and a control group that was treated with its predecessor versions, using inverse probability of treatment weighting.

RESULTS

Thirty-eight aneurysms treated with a Woven EndoBridge 17 (mean size, 4.9 ± 1.5 mm) and 70 treated with a predecessor version of the Woven EndoBridge 17 (mean size, 5.6 ± 1.4 mm) were included. The predecessor version of the Woven EndoBridge 17 had a higher failure rate (10.3%) than the Woven EndoBridge 17 (0%, P = .05). Additional stent placement was performed more often with the predecessor version of the Woven EndoBridge 17 (10.0%) than with the Woven EndoBridge 17 (2.6%, adjusted P = .005). The predecessor version of the Woven EndoBridge 17 was associated with a higher thromboembolic event rate (14.3%) than the Woven EndoBridge 17 (5.3%, adjusted P = .002). Neurologic complications (Woven EndoBridge 17: 2.6%; predecessor version of the Woven EndoBridge 17: 2.9%, adjusted P = 1.0) and immediate complete aneurysm occlusion rates (Woven EndoBridge 17: 57.9%; predecessor version of the Woven EndoBridge 17: 54.3%, adjusted P = .21) did not differ significantly between groups.

CONCLUSIONS

In the current study, the Woven EndoBridge 17 was associated with a potentially lower thromboembolic event rate than the predecessor version of the Woven EndoBridge 17, without compromising the immediate aneurysm occlusion rate. Long-term clinical and angiographic outcome analysis will be necessary to draw a definite conclusion.

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.

In vitro investigation of chemical properties and biocompatibility of neurovascular braided implants

Braiding of Nitinol micro wires is an established technology for the manufacturing of fine-meshed neurovascular implants for tortuous vessel geometries. Electropolishing of wires before the braiding process has the potential to improve the in vitro behaviour in terms of thrombogenicity and endothelial cell proliferation. In this study, we present the first in vitro investigation of braided electropolished/blue oxide Nitinol samples in a blood flow loop, showing a significantly lower activation of the coagulation pathway (represented by the TAT III marker) and a tendency towards reduced platelet adhesion. Furthermore, we applied the same surface treatment on flat disks and measured protein adhesion as well as endothelial cell proliferation. We compared our results to non-electropolished samples with a native oxide surface. While platelet deposition was reduced on electropolished/blue oxide surface, a significant increase of endothelial cell seeding was observed. Investigation of inflammatory marker expression in endothelial cells provided divergent results depending on the marker tested, demanding closer investigation. Surface analysis using Auger electron spectroscopy revealed a thin layer mainly consisting of titanium oxynitride or titanium oxide + titanium nitride as a potential cause of the improved biological performance. Translated to the clinical field of intracranial aneurysm treatment, the improved biocompatibility has the potential to increase both safety (low thrombogenicity) and effectiveness (aneurysm neck reconstruction).

Intravenous versus intra-arterial digital subtraction angiography: Occlusion rate and complication assessment of experimental aneurysms after flow diverter treatment in rabbits

PURPOSE

Conventional intra-arterial digital subtraction angiography, which requires surgical exposure and ligation of the femoral or carotid artery, is a limited method of evaluating elastase-induced aneurysms in New Zealand white rabbits. The purpose of this study was to assess aneurysm morphology, occlusion rates and complications after flow diverter treatment comparing intravenous and intra-arterial digital subtraction angiography.

METHODS

We previously published a preclinical study in which we evaluated the occlusion rates of elastase-induced aneurysms after treatment with a prototype flow diverter, by using intra-arterial digital subtraction angiography at three months ( n = 9) and six months ( n = 9). In addition to that intravenous digital subtraction angiography before treatment, after one month (early follow-up group) and after three months (late follow-up group) was performed. Occlusion rates were compared within the two groups by means of residual contrast filling.

RESULTS

Baseline aneurysm characteristics revealed no significant differences between intra-arterial digital subtraction angiography and intravenous digital subtraction angiography. Aneurysm occlusion rates in both follow-up groups using intravenous digital subtraction angiography were significantly higher compared to intra-arterial digital subtraction angiography (early follow-up group: intravenous digital subtraction angiography (one month) versus intra-arterial digital subtraction angiography (three months); p = 0.03 and late follow-up group: intravenous digital subtraction angiography (three months) versus intra-arterial digital subtraction angiography (six months); p = 0.04). Intravenous digital subtraction angiography is feasible to detect and reproduce device occlusions, in-stent stenosis and post-stent stenosis.

CONCLUSION

Intravenous digital subtraction angiography can not give a sufficient statement on the aneurysm occlusion process compared to intra-arterial digital subtraction angiography and is therefore not recommended for imaging follow-up after flow diverter treatment in rabbits. Regarding untreated aneurysms and complications like device occlusions, in-stent stenosis and post-stent stenosis intravenous digital subtraction angiography proofed to be a good alternative to intra-arterial digital subtraction angiography in our study.

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

Background

The Derivo Embolization Device (DED) is a novel flow diverter with advanced X-ray visibility, potentially lower thrombogenicity, and an improved delivery system.

Objective

To evaluate the safety and efficacy of the DED for emergency treatment of ruptured intracranial aneurysms.

Methods

Between February 2016 and March 2018, 10 patients (median age 54.5 years, seven women) with 11 aneurysms were treated with the DED at three neurovascular centers. Procedural details, complications, morbidity, and aneurysm occlusion (O’Kelly-Marotta scale, OKM) were retrospectively reviewed.

Results

Among 11 aneurysms treated, there were nine anterior circulation and two posterior circulation aneurysms. Aneurysm morphology was saccular in four cases, dissecting in three, blister-like in three, and fusiform in one. In each case, a single DED was implanted and deployment was technically successful without exception. Adjunctive coiling was performed in two aneurysms. We observed one in-stent thrombosis, presumably due to low response to clopidogrel 4 days after the procedure, which remained with a mild hemiparesis after aspiration thrombectomy. No further thromboembolic or hemorrhagic events occurred. Favorable outcome (modified Rankin scale score ≤2) at last follow-up was achieved in all patients. Among 10 aneurysms available for angiographic follow-up, complete aneurysm occlusion (OKM D) was obtained in nine cases (90.0%).

Conclusions

In this pilot study, endovascular treatment of ruptured intracranial aneurysms with the DED was feasible and not associated with any incidence of rebleeding. Larger series with longer follow-up are warranted to reach a definite conclusion about this device.

Transient in-stent stenosis: a common finding after flow diverter implantation

Background and purpose

In recent years, implantation of flow diverters has emerged as an option for the endovascular treatment of intracranial aneurysms. One complication of treatment with flow diverters is the occurrence of in-stent stenosis, which has been reported to be partially reversible. The purpose of our study was to assess the incidence and dynamics of in-stent stenosis on angiographic short term and long term follow-up after treatment with flow diverters.

Methods

A retrospective review of our prospectively maintained database identified all patients with intracranial internal carotid artery (ICA) aneurysms treated by flow diverters at our institution between 2014 and 2017. Clinical charts, procedural data, and angiographic results were reviewed.

Results

18 patients were included. The mean short term follow-up was 92±19 days and mean long term follow-up was 449±120 days after treatment. No neurologic complications were observed. There was no procedure related mortality. Long term angiographic results showed complete occlusion in 83.3%, neck remnants in 11.1%, and incomplete occlusion in 5.5% of cases. In-stent stenosis was observed in all cases. Mean stenosis improved significantly from 30% on short term follow-up to 12% on long-term follow-up (P<0.0001).

Conclusion

In-stent stenosis is a common finding on short term follow-up after the treatment with flow diverters but improves over time.

Evaluation of Pipeline Flex delivery system for the treatment of unruptured aneurysms

INTRODUCTION

Refinements in endovascular technology have revolutionized the treatment of intracranial aneurysms (IAs) with the development of flow-diversion technology. The first generation of the Pipelin Embolization Device (PED) has demonstrated its safety and efficacy. However, the deployment technique was a difficult task that often led to complex maneuvers. The Pipeline Flex Embolization Device (PED Flex) is the second generation and its introduction has arrived with high expectations due to a completely redesigned delivery system that intends to overcome deployment difficulties seen in the previous generation. Areas covered: Preclinical studies, mechanism of action of flow-diverters, technical aspects and deployment system of the PED Flex, and clinical outcomes with both PED generations. Expert commentary: Flow diversion has allowed us to treat lesions that would be otherwise challenging for surgical clipping or unsuitable for other endosaccular strategies. Although the experience with PED Flex is limited, initial results suggest its safety and short-term efficacy.

Mid-term and long-term follow-up of intracranial aneurysms treated by the p64 Flow Modulation Device: a multicenter experience

Background

Experience with the endovascular treatment of cerebral aneurysms using the p64 Flow Modulation Device is still limited. This study discusses the results and complications of this new flow diverter device.

Methods

40 patients (30 women, 10 men) with 50 cerebral aneurysms treated in six Italian neurointerventional centers with the p64 Flow Modulation Device between April 2013 and September 2015 were retrospectively reviewed.

Results

Complete occlusion was obtained in 44/50 aneurysms (88%) and partial occlusion in 3 (6%). In the other three aneurysms (6%), two cases of asymptomatic in-stent thrombosis and one intraprocedural occlusion of the parent vessel occurred. Technical complications were observed in eight procedures (16%). Permanent morbidity due to acute in-stent thrombosis and consequent ischemic stroke occurred in one patient (2.5%). No delayed aneurysm rupture, subarachnoid or intraparenchymal hemorrhage, or ischemic complications occurred and there were no deaths.

Conclusions

Endovascular treatment with the p64 Flow Modulation Device is a safe treatment for unruptured cerebral aneurysms, resulting in a high rate of occlusion. As with other flow diverter devices, we recommend this treatment mainly for large-necked aneurysms of the internal carotid artery siphon. However, endovascular treatment with the p64 device should also be encouraged in difficult cases such as aneurysms of the posterior circulation and beyond the circle of Willis.