Pipeline Flex embolisation device with Shield Technology for the treatment of patients with intracranial aneurysms: periprocedural and 6 month outcomes

Comparison of Thromboembolic Events Between Pipeline Embolization Device (PED) Shield and PED/PED Flex: A Propensity Score-Matched Analysis

BACKGROUND AND OBJECTIVES

The pipeline embolization device (PED) Flex with Shield technology is a third-generation flow diverter used for intracranial aneurysm treatment designed to decrease thrombogenicity through a phosphorylcholine coating. Herein, we aim to compare the rate of thromboembolic events in PED with Shield technology and PED without it through propensity score matching.

METHODS

We conducted a retrospective analysis of aneurysms treated with PED first-generation/PED Flex and PED with Shield between 2013 and 2023 at a single academic institution. Patients were matched through propensity score by controlling for confounding factors including age, smoking history, diabetes, previous subarachnoid hemorrhage, modified Rankin Scale pretreatment, location, aneurysm size, previous treatment, and clopidogrel or aspirin resistance. After matching, we evaluated for periprocedural and postoperative thromboembolic events. Data analysis was performed using Stata 14.

RESULTS

A total of 543 patients with 707 aneurysms treated in 605 procedures were included in the analysis. From these, 156 aneurysms were treated with PED with Shield (22.07%) and 551 (77.93%) without Shield technology. Propensity score matching resulted in 84 matched pairs. The rate of thromboembolic events was 3.57% for PED Shield and 10.71% for PED first-generation/PED Flex ( P = .07), while retreatment rates were 2.38% for PED Shield and 8.32% for PED Flex ( P = .09). Complete occlusion at first ( P = .41) and last imaging follow-up ( P = .71), in-stent stenosis ( P = .95), hemorrhagic complications ( P = .31), and functional outcomes ( P = .66) were comparable for both groups.

CONCLUSION

This is the first study in the literature performing a propensity scored-matched analysis comparing PED with PED with Shield technology. Our study suggests a trend toward lower thromboembolic events for PED Shield, even after controlling for aspirin and clopidogrel resistance, and a trend toward lower aneurysm retreatment rates with PED Shield, without reaching statistical significance.

Initial Experience with the Derivo 2Heal Flow Diverter under Standard or Reduced-Dose Single Antiplatelet Therapy

BACKGROUND AND PURPOSE

Flow diverters with surface modifications or coatings have been recently introduced to clinical practice with the expectation that they can reduce the rate of thromboembolic complications and residual aneurysms. The purpose of this study is to evaluate the utility of the Derivo 2Heal (D2H) device, a new fibrin and heparin-coated flow diverter.

MATERIALS AND METHODS

Patients treated by a single operator by using the D2H were retrospectively evaluated for demographic data, aneurysm characteristics, procedural variables, and follow-up data. All patients were treated by using a single D2H, monitored by platelet function testing and kept under single antiplatelet therapy with regular or half-dose clopidogrel or prasugrel after the procedure.

RESULTS

Twenty patients with 26 aneurysms were treated. Three presented acutely with subarachnoid hemorrhage. Adjunctive devices were used in 6 patients. There were no technical failures and 2 periprocedural self-limited nonthrombotic minor adverse events. During follow-up, 1 of the acutely ruptured aneurysms reruptured, and 1 patient had a visual TIA. All patients were doing well clinically (19 with mRS of 0 and 1 with 1) at the last follow-up after discharge. The rates of total occlusion on very early angiographic (MRA/CTA or DSA, mean: 2.4 months), DSA (mean: 5.8 months), and midterm angiographic (mean: 14.5 months) follow-up for all versus uncoiled aneurysms were 68% versus 70%, 77.8% versus 90.0%, and 91.7% versus 90.1%, respectively.

CONCLUSIONS

The absence of permanent neurologic deficits in the periprocedural period and favorable occlusion rates in this preliminary study suggest that the novel coating comprising fibrin and heparin may have the potential to increase the safety and efficacy of flow diversion and needs to be further studied by comparing the D2H device with its bare counterpart and other coated or surface-modified flow diverters.

Flow Diverters with Surface Modification in Patients with Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND

Flow diverters with surface modification (FDSM) are increasingly being used in the treatment of intracranial aneurysms (ANs). We aimed to evaluate the effectiveness and safety across different devices and antiplatelet therapies using a systematic review and meta-analysis.

METHODS

A systematic review was performed to identify original studies of ≥10 patients with intracranial ANs treated with FDSM from database inception through August 2023. Primary effectiveness outcome was the rate of complete AN occlusion at follow-up ≥6 months. Safety outcomes included ischemic stroke, hemorrhage, and in-stent thrombosis, and were stratified by FDSM devices and antiplatelet therapies. Certainty of evidence was evaluated following the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Twenty-seven studies were included, yielding 2161 patients with 2373 ANs. A total of 70.5% of the ANs were located on the internal carotid artery (ICA). Total 10.3% were acutely ruptured. The complete AN occlusion rate was 72.3% at follow-up ≥6 months. Sensitivity analysis in the ICA AN cohort yielded comparable occlusion rates between Pipeline Flex Embolization Device-Shield (80.4%) and Phenox-hydrophilic polymer-coated (77.5%, P = 0.54), but a lower 66.2% rate for Flow Redirection Endoluminal Device-X (P = 0.02). The rate of in-stent thrombosis and stenosis tended to be higher in Phenox-hydrophilic polymer-coated (3.4%) and Flow Redirection Endoluminal Device-X (4.3%) versus Pipeline Flex Embolization Device-Shield (0.8%, P = 0.05).

CONCLUSIONS

FDSM were safe with satisfactory effectiveness for intracranial ANs. More specific investigations are warranted to explore their performance in ANs beyond the ICA and optimal antiplatelet therapy.

Angiographic and clinical outcomes from 396 aneurysms treated with the pipeline flex embolization device with shield technology

BACKGROUND

The PEDESTRIAN registry demonstrated high rates of complete long-term occlusion and good clinical outcomes among patients with intracranial aneurysms treated with the pipeline embolization device. The pipeline flex embolization device with shield technology was introduced to minimize thromboembolic complications. In this study, we investigated the safety and effectiveness of pipeline embolization device with shield technology among all patients treated for intracranial aneurysms at our center.

METHODS

This was a single-arm retrospective study of prospectively collected data of patients treated with pipeline embolization device with shield technology at our high-volume center between January 2018-January 2021. The primary efficacy endpoint was complete occlusion as measured by a class 1 Raymond-Roy score at 1-year and 2-year follow-up. The primary safety endpoint was major morbidity and neurological mortality up to 1 year following intervention.

RESULTS

A total of 328 patients (mean age 56.1 ± 14.7 years; 81.1% female), 80 of whom were previously included in PEDESTRIAN, with 396 aneurysms, were analyzed. A total of 378 devices were deployed, with 93.9% (372/396) of aneurysms requiring only one device. Follow-up angiography was available for 90.2% (296/328) of the procedures after a mean time of 14.0 ± 8.2 months. Complete occlusion was demonstrated for 78.5% (132/168) of aneurysms at 12 months and 90.7% (98/108) at 24 months. The overall rates of major morbidity and neurological mortality after 2 years were 1.5% (5/328) and 0.6% (2/328), respectively.

CONCLUSION

Our results demonstrate high rates of complete long-term occlusion among patients treated with pipeline embolization device with shield technology. We also observed low rates of mortality and morbidity consistent with fewer thromboembolic complications with pipeline embolization devices with shield technology.

Aneurysm Treatment With the Pipeline Vantage Embolization Device in Retrospective Evaluation: Periprocedural Results from the Pipe-VADER Study

OBJECTIVE

The Pipeline Vantage Embolization Device is a fourth-generation flow diverter with an antithrombotic coating and a reduced profile compared to previous Pipeline versions. The objective of this study was to evaluate the procedural feasibility, safety, and efficacy of this device.

METHODS

The Pipe-VADER study was designed as a retrospective, observational study of consecutive patients treated with the Vantage at 3 neurovascular centers. Patient and aneurysm characteristics, procedural parameters, early complications, and extent of postinterventional contrast retention were analyzed on an intention-to-treat basis.

RESULTS

Twenty-eight patients with 31 aneurysms (median size: 5.0 mm, posterior circulation: 4 [12.9%], ruptured: 5 [16.1%]) were included. The technical success rate was 100%, with multiple stents used in 4/30 (13.3%) procedures. Of the 30 procedures, adjunctive coiling was performed in 3 (10.0%) and balloon angioplasty in 2 (6.7%). Median procedure time was 62 minutes. Procedural ischemic stroke occured in 4 (13.3%) cases, whereof 2 were major strokes (6.6%). There were no hemorrhagic complications. Initial contrast retention was observed in 29/31 (93.5%) aneurysms. All 27 overstented side vessels were patent at the end of the procedure. Short-term follow-up (median: 5 months) showed complete and favorable occlusion rates of 70% (14/20) and 80% (16/20), respectively.

CONCLUSIONS

The new Pipeline Vantage appears to be safe and feasible for the treatment of intracranial aneurysms and warrants further evaluation.

Surface modification of neurovascular stents: from bench to patient

Flow-diverting stents (FDs) for the treatment of cerebrovascular aneurysms are revolutionary. However, these devices require systemic dual antiplatelet therapy (DAPT) to reduce thromboembolic complications. Given the risk of ischemic complications as well as morbidity and contraindications associated with DAPT, demonstrating safety and efficacy for FDs either without DAPT or reducing the duration of DAPT is a priority. The former may be achieved by surface modifications that decrease device thrombogenicity, and the latter by using coatings that expedite endothelial growth. Biomimetics, commonly achieved by grafting hydrophilic and non-interacting polymers to surfaces, can mask the device surface with nature-derived coatings from circulating factors that normally activate coagulation and inflammation. One strategy is to mimic the surfaces of innocuous circulatory system components. Phosphorylcholine and glycan coatings are naturally inspired and present on the surface of all eukaryotic cell membranes. Another strategy involves linking synthetic biocompatible polymer brushes to the surface of a device that disrupts normal interaction with circulating proteins and cells. Finally, drug immobilization can also impart antithrombotic effects that counteract normal foreign body reactions in the circulatory system without systemic effects. Heparin coatings have been explored since the 1960s and used on a variety of blood contacting surfaces. This concept is now being explored for neurovascular devices. Coatings that improve endothelialization are not as clinically mature as anti-thrombogenic coatings. Coronary stents have used an anti-CD34 antibody coating to capture circulating endothelial progenitor cells on the surface, potentially accelerating endothelial integration. Similarly, coatings with CD31 analogs are being explored for neurovascular implants.

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.

Single antiplatelet regimen in flow diverter treatment of cerebral aneurysms: The drug matters. A systematic review and meta-analysis

BACKGROUND

Hemorrhagic and thromboembolic complications (TECs) are the main concerns in the endovascular treatment of intracranial aneurysms using flow diverter devices (FDs). The clinical demand for single antiplatelet therapy (SAPT) is increasing especially with the development of devices with lower thrombogenicity profile. However, the safety of SAPT is not well established.

OBJECTIVE

To analyze the safety and efficacy of SAPT in terms of ischemic and hemorrhagic complications in patients undergoing FDs treatment for cerebral aneurysms.

METHODS

A systematic literature search and meta-analysis were conducted in PubMed, Ovid MEDLINE, Ovid Embase, and Web of Science from January 2010 until October 2022. Twelve articles which reported SAPT and data on hemorrhagic, TECs, and mortality following FDs treatment were included.

RESULTS

Overall, the 12 studies involved 237 patients with 295 aneurysms. Five investigated the safety and efficacy of SAPT in 202 unruptured aneurysms. Six studies focused on 57 ruptured aneurysms. One study included both ruptured and unruptured aneurysms. Among the 237 patients, prasugrel was most often used as SAPT in 168 cases (70.9%), followed by aspirin in 42 (17.7%) patients, and by ticagrelor in 27 (11.4%). Overall, the hemorrhagic complication rate was 0.1% (95% CI 0% to 1.8%). The TEC rate was 7.6% (95% CI 1.7% to 16.1%). In the subgroup analysis, the TEC rates of prasugrel monotherapy of 2.4% (95% CI 0% to 9.3%) and ticagrelor monotherapy of 4.2% (95% CI 0.1% to 21.1%) were lower than of aspirin monotherapy 20.2% (95% CI 5.9% to 38.6%). The overall mortality rate was 1.3% (95% CI 0% to 6.1%).

CONCLUSION

According to the available data, SAPT regimen in patients undergoing FDs treatment for cerebral aneurysms has an acceptable safety profile, especially with the use of ADP-receptor antagonists.

A Systematic Literature Review and Meta-Analysis of the Treatment of Ruptured Intracranial Aneurysms with Hydrophilic Polymer and Phosphorylcholine-Coated Flow Diverters Under Single Antiplatelet Therapy

OBJECTIVE

Flow diverters coated with antithrombogenic substances were recently introduced and have shown encouraging results in the preclinical setting. Our aim was to analyze their clinical application in patients with ruptured intracranial aneurysms using single antiplatelet therapy (SAPT).

METHODS

We performed a PRISMA-compliant systematic review and meta-analysis covering 3 major data bases until March 2022.Two reviewers independently reviewed clinical studies for eligibility.Random-effects analysis of proportions was used to pool safety outcomes (hemorrhagic, thrombembolic, and overall complications). Studies were tested for publication bias and heterogeneity.

RESULTS

Five studies reporting 43 patients with 46 aneurysms were identified. More than 1 stent was implanted in 16%, and additional coil embolization was performed in 53.8% of patients. SAPT with one of various acetylsalicylic acid regimens was used in 86%, altogether antiplatelet protocols were variable. The pooled risks of thromboembolic (23.9%; 95% confidence interval [CI], 9.6-47.9), hemorrhagic (9.4%; 95% CI, 3.6-22.6), and overall complications (28.3%; 95% CI, 12.4-52.5) were calculated in the absence of publication bias with low to moderate study heterogeneity measures. All complications occurred in patients under acetylsalicylic acid SAPT. Adequate aneurysm occlusion was described in 65.5% of patients.few retrospective observational studies with moderate heterogeneity, encompassing a limited number of patients treated with variable SAPT regimens.

CONCLUSIONS

Flow diversion for ruptured aneurysms under SAPT with coated stents is feasible. Although the risk of hemorrhagic complications was low, thromboembolic complications occurred in a significant number of patients, all under ASA SAPT.

Clinical outcomes of pipeline embolization devices with shield technology for treating intracranial aneurysms

INTRODUCTION

As a common endovascular treatment for intracranial aneurysms, the pipeline embolization device (PED) is considered a standard treatment option, especially for large, giant, wide-necked, or dissecting aneurysms. A layer of phosphorylcholine biocompatible polymer added to the surface of the PED can substantially improve this technology. This PED with shield technology (pipeline shield) is relatively novel; its early technical success and safety have been reported. We conducted a systematic literature review with the aim of evaluating the efficacy and safety of the pipeline shield.

METHODS

We searched the PubMed, Embase, and Cochrane databases, following the preferred reporting items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines.

RESULTS

We selected five prospective and two retrospective studies for review. A total of 572 aneurysms were included; of these, 506 (88.5%) were unruptured. The antiplatelet regimens were heterogeneous. The rate of perioperative and postoperative complications was 11.1% [95% confidence interval (CI): 6.5-18.9%]. The adequate occlusion rate at 6 months was 73.9% (95% CI: 69.1-78.7%). The adequate occlusion rate of more than 12 months was 80.9% (95% CI: 75.1-86.1%). The mortality rate was 0.7% (95% CI: 0.2-1.5%). Subgroup analyses showed that aneurysm rupture status had no effect on aneurysm occlusion rate, patient morbidity, or mortality.

CONCLUSION

This review demonstrates the safety and efficacy of the pipeline shield for treating intracranial aneurysms. However, direct comparisons of the pipeline shield with other flow diverters are needed to better understand the relative safety and effectiveness of different devices.

The Pipeline Embolization Device: a decade of lessons learned in the treatment of posterior circulation aneurysms in a multicenter cohort

OBJECTIVE

The Pipeline Embolization Device (PED) has prompted a paradigm shift in the approach to posterior circulation aneurysms. The year 2021 marks a decade since FDA approval of this flow diverter, and during this time operators have adapted to its off-label uses. The authors examined whether case selection, practice trends, and patient outcomes have changed over this 10-year period.

METHODS

This study is a retrospective review of consecutive posterior circulation aneurysms managed with the PED at four academic institutions in the US between January 1, 2011, and January 1, 2021. Factors related to case selection, rates of aneurysm occlusion, or complications were identified and evaluated. Angiographic outcomes as well as thromboembolic and hemorrhagic complications were investigated.

RESULTS

This study included 117 patients (median age 60 years). At a median follow-up of 12 months, adequate occlusion (> 90%) was attained in 73.2% of aneurysms. Aneurysm occlusion rates were similar over the study interval. Thromboembolic and hemorrhagic complications were reported in 12.0% and 6.0% of the procedures, respectively. There was a nonsignificant trend toward a decline in the rate of thromboembolic (14.1% in 2011-2015 vs 9.4% in 2016-2021, p = 0.443) and hemorrhagic (9.4% in 2011-2015 vs 1.9% in 2016-2021, p = 0.089) complications.

CONCLUSIONS

The authors observed a trend toward a decline in the rate of thromboembolic and hemorrhagic complications with improved operator experience in using the PED for posterior circulation aneurysms. The use of single-device PED flow diversion significantly increased, as did the tendency to treat smaller aneurysms and observe large unruptured fusiform/dolichoectatic lesions. These findings reflect changes attributable to evolving judgment with maturing experience in PED use.

Biomimetic materials based on zwitterionic polymers toward human-friendly medical devices

This review summarizes recent research on the design of polymer material systems based on biomimetic concepts and reports on the medical devices that implement these systems. Biomolecules such as proteins, nucleic acids, and phospholipids, present in living organisms, play important roles in biological activities. These molecules are characterized by heterogenic nature with hydrophilicity and hydrophobicity, and a balance of positive and negative charges, which provide unique reaction fields, interfaces, and functionality. Incorporating these molecules into artificial systems is expected to advance material science considerably. This approach to material design is exceptionally practical for medical devices that are in contact with living organisms. Here, it is focused on zwitterionic polymers with intramolecularly balanced charges and introduce examples of their applications in medical devices. Their unique properties make these polymers potential surface modification materials to enhance the performance and safety of conventional medical devices. This review discusses these devices; moreover, new surface technologies have been summarized for developing human-friendly medical devices using zwitterionic polymers in the cardiovascular, cerebrovascular, orthopedic, and ophthalmology fields.

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.

Giant Aneurysm Management

The treatment of giant aneurysms has always been a challenge in the field of neurovascular disease. Giant aneurysms are larger in size and are associated with thrombosis development and the calcification of the aneurysmal wall and neck, which often interfere with direct clipping. Most giant aneurysms have a wide neck with an incomplete thrombus, making complete embolization almost impossible. Giant aneurysms of different sites have entirely different hemodynamic characteristics. Moreover, aneurysms at the same site may exhibit very different hemodynamics among different individuals. Therefore, careful assessment of each case is required before and during treatment to develop and carry out an individualized treatment plan.

First U.S. Experience Using the Pipeline Flex Embolization Device with Shield Technology for Treatment of Intracranial Aneurysms

BACKGROUND

The Pipeline Flex Embolization Device with Shield technology (PED-Shield [Medtronic, Dublin, Ireland]) is a third-generation flow diverter. Surface modification of the mesh with phosphorylcholine covalently bound to the metal struts aims to reduce thrombogenicity. In the present study, we report the results from the first U.S. series of patients with intracranial aneurysms treated with the PED-Shield and a comprehensive systematic literature review.

METHODS

We retrospectively collected the patient demographics, aneurysm characteristics, procedural details, and periprocedural complications from our prospectively maintained endovascular database (April 2021 to July 2021). Our literature review encompassed 3 databases (PubMed, Embase, and MEDLINE).

RESULTS

Ten patients with 11 anterior circulation unruptured wide-necked aneurysms (10 saccular, 1 fusiform) were included. The average patient age was 64.7 years (range, 45-86 years), and 9 were women. One device demonstrated insufficient distal opening. No other technical issues or intraprocedural complications had occurred. After the procedure, 1 patient had developed a groin hematoma and 1 had experienced a small intracranial hemorrhage, with no clinical repercussions. All patients were discharged with dual-antiplatelet therapy. In the review, we identified 15 studies. Most had been conducted in Europe and South America and 3 were U.S. case reports of compassionate use of the device.

CONCLUSIONS

In our initial periprocedural experience with the PED-Shield for intracranial aneurysm treatment, the device demonstrated an excellent performance and no major complications. Further studies are required to evaluate the long-term follow-up results and the safety of different antiplatelet regimens.

Antiplatelet Therapy and Periprocedural Risk Factor Analysis for Pipeline Embolization Device Treatment of Unruptured Internal Carotid Artery Aneurysms: A Retrospective, Multicenter Analysis

BACKGROUND

Aneurysm treatment using the Pipeline Embolization Device has been established but appropriate maintenance of dual antiplatelet therapy (APT) is essential. This multicenter retrospective study assessed whether APT was properly adjusted for clopidogrel resistance and identified risk factors associated with periprocedural complications.

METHODS

Consecutive cases of use of the Pipeline Embolization Device for internal carotid artery aneurysms (>10 mm) between November 2015 and April 2020 were analyzed. Dual APT (aspirin + clopidogrel) was prescribed before treatment. If preprocedural P2Y12 reaction unit (PRU) values were >240, APT was adjusted. Periprocedural complications were compared between APT nonadjustment and adjustment groups and periprocedural risk factors were also analyzed.

RESULTS

A total of 162 procedures were assessed. The mean maximum aneurysm size was 15.35 mm. APT adjustment was required in 47 cases (29.0%), primarily by switching to prasugrel. There were no significant differences in complication incidence between the 2 groups even after propensity score matching. The risk factor independently associated with ischemic complications was a neck size of 8 mm or larger (odds ratio [OR], 5.25; P = 0.018) and restricting analysis to the APT nonadjustment group showed PRU values of 190 or higher (OR, 5.84; P = 0.047) and neck sizes of 8 mm or larger (OR, 7.05; P = 0.029) as significant factors. The risk factor independently associated with hemorrhagic complications was a neck size of 7 mm or larger (OR, 11.57; P = 0.023).

CONCLUSIONS

APT adjustment for clopidogrel resistance was safe and effective. Neck width was a risk factor for both ischemic and hemorrhagic complications. PRU values of 190 or higher were also associated with ischemic complications.

First Experience of Three Neurovascular Centers With the p64MW-HPC, a Low-Profile Flow Diverter Designed for Proximal Cerebral Vessels With Antithrombotic Coating

Background: In the last decade, flow diversion (FD) has been established as hemodynamic treatment for cerebral aneurysms arising from proximal and distal cerebral arteries. However, two significant limitations remain—the need for 0.027” microcatheters required for delivery of most flow diverting stents (FDS), and long-term dual anti-platelet therapy (DAPT) in order to prevent FDS-associated thromboembolism, at the cost of increasing the risk for hemorrhage. This study reports the experience of three neurovascular centers with the p64MW-HPC, a FDS with anti-thrombotic coating that is implantable via a 0.021” microcatheter.

Materials and methods: Three neurovascular centers contributed to this retrospective analysis of patients that had been treated with the p64MW-HPC between March 2020 and March 2021. Clinical data, aneurysm characteristics, and follow-up results, including procedural and post-procedural complications, were recorded. The hemodynamic effect was assessed using the O'Kelly–Marotta Scale (OKM).

Results: Thirty-two patients (22 female, mean age 57.1 years) with 33 aneurysms (27 anterior circulation and six posterior circulation) were successfully treated with the p64MW-HPC. In 30/32 patients (93.75%), aneurysmal perfusion was significantly reduced immediately post implantation. Follow-up imaging was available for 23 aneurysms. Delayed aneurysm perfusion (OKM A3: 8.7%), reduction in aneurysm size (OKM B1-3: 26.1%), or sufficient separation from the parent vessel (OKM C1-3 and D1: 65.2%) was demonstrated at the last available follow-up after a mean of 5.9 months. In two cases, device thrombosis after early discontinuation of DAPT occurred. One delayed rupture caused a caroticocavernous fistula. The complications were treated sufficiently and all patients recovered without permanent significant morbidity.

Conclusion: Treatment with the p64MW-HPC is safe and feasible and achieves good early aneurysm occlusion rates in the proximal intracranial circulation, which are comparable to those of well-established FDS. Sudden interruption of DAPT in the early post-interventional phase can cause in-stent thrombosis despite the HPC surface modification. Deliverability via the 0.021” microcatheter facilitates treatment in challenging vascular anatomies.

Early clinical experience with the p48MW HPC and p64MW HPC flow diverters in the anterior circulation aneurysm using single anti-platelet treatment

Background

The p64MW HPC and p48MW HPC flow diverters have reduced thrombogenicity due to hydrophilic coating. The purpose of this study was to evaluate its safety and efficacy in Mongolian patients under single antiplatelet therapy (SAPT) with prasugrel.

Materials and methods

We performed a retrospective review of patients enrolled into our prospectively maintained database to identify all patients treated with either the p48MW HPC or p64MW HPC under SAPT. We recorded baseline demographics, aneurysm size and location, procedural complications, angiographic and clinical results.

Results

24 patients, (female = 21, 87.5%), age 48.2 ± 11.6 years (range 25–63) underwent treatment of 30 aneurysms with either p64MW HPC or p48MW HPC. All aneurysms were saccular with dome width 8.2 ± 6.5 (range 1.6–26.0 mm) and dome height 7.6 ± 6.7 (range 1.6–30.0 mm). None of the aneurysms were previously treated. The average PRU was 54.6 ± 31.2 (range 1–127) on pre-operative VerifyNow testing. Angiographic follow-up was available for 13 patients (17 aneurysms), 183 ± 36 days post-procedure, at which point 64.7% of aneurysms (n = 11/17) were completely occluded and 11.8% (n = 2/17) had only neck remnants resulting in 76.5% of aneurysms being adequately occluded A single intra-operative complication (4.2%) occurred however all patients were mRS ≤1 at last follow-up. There were two post-operative complications neither of which resulted in permanent neurological morbidity. There were no instances of post-operative aneurysmal rupture or delayed parenchymal haemorrhage. The overall mortality was 0%.

Conclusion

The efficacy and safety of p64MW HPC coated devices under SAPT is similar to uncoated flow diverters that require DAPT.

Delayed leukoencephalopathy from suspected polymer embolism after neuroendovascular procedures

As the neurointervention field grows, a new side effect emerges. Delayed leukoencephalopathy (DL) is believed to be an inflammatory or allergic reaction to polymer material that is shed from catheters during endovascular procedures. We present four cases of DL after aneurysm treatment in two patients, endovascular stroke treatment and diagnostic arteriography. We present our diagnostic process, including biopsy results in two patients, our anti-inflammatory treatment and outcomes together with a review of the literature. In our series, prognosis was variable with ongoing seizures in two patients. Our literature review reveals that asymptomatic shedding of polymer material is common, occurring in a third of endovascular stroke procedures, whereas symptomatic DL occurs in <0.5% of therapeutic neuroendovascular procedures. Clinicians should be aware of this rare complication, and oral glucocorticoids seem to be a reasonable first-line treatment strategy.

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.