Cerebral foreign body reaction after carotid aneurysm stenting

Longitudinal radiological follow-up of individual level non-ischemic cerebral enhancing lesions following endovascular aneurysm treatment

BACKGROUND

Non-ischemic cerebral enhancing (NICE) lesions following aneurysm endovascular therapy are exceptionally rare, with unknown longitudinal evolution.

OBJECTIVE

To evaluate the radiological behavior of individual NICE lesions over time.

METHODS

Patients included in a retrospective national multicentric inception cohort were analyzed. NICE lesions were defined, using MRI, as delayed onset punctate, nodular, or annular foci enhancements with peri-lesion edema, distributed in the vascular territory of the aneurysm treatment, with no other confounding disease. Lesion burden and the longitudinal behavior of individual lesions were assessed.

RESULTS

Twenty-two patients were included, with a median initial lesion burden of 36 (IQR 17-54) on the first MRI scan. Of the 22 patients with at least one follow-up MRI scan, 16 (73%) had new lesions occurring mainly within the first 200 weeks after the date of the procedure. The median number of new lesions per MRI was 6 (IQR 2-16). Among the same 22 patients, 7 (32%) had recurrent lesions. The median persistent enhancement of a NICE lesion was 13 weeks (IQR 6-30). No factor was predictive of early regression of enhancement activity with lesion regression kinetics mainly being patient-dependent.

CONCLUSIONS

The behavior of individual NICE lesions was found to be highly variable with an overall patient-dependent regression velocity.

Fragmentation of Hydrophilic Guidewire Coatings During Neuroendovascular Therapy

PURPOSE

Cerebral polymer coating embolism from intravascular devices may cause serious complications after endovascular therapy (EVT) for neurovascular diseases. Although polymer fragments are often created during endovascular procedures, exact mechanisms of their formation, especially if of small size, are largely unknown.

METHODS

In this study eight microguidewires (Asahi Chikai 200 cm (Asahi Intecc, Aichi, Japan), Asahi Chikai Black (Asahi Intecc), Fathom™ (Boston Scientific, Marlborough, MA, USA), Hybrid (Balt Extrusion, Montmorency, France), Radifocus® Guide Wire GT (Terumo, Leuven, Belgium), Synchro2® (Stryker, Kalamazoo, MI, USA), Transend™ EX (Boston Scientific), and Traxcess™ (MicroVention®, Tustin, CA, USA)) frequently used during EVT were investigated ex vivo using their dedicated metal or plastic insertion tools to assess for coating delamination after backloading of the microguidewires.

RESULTS

Backloading caused damage to the coating of all microguidewires especially when the main body of the guidewires was bent in front of the insertion tool. All studied microguidewires produced microscopic filamentous and/or band-like coating fragments. Few larger irregular fragments were observed, but also very small fragments measuring 1-3 µm in diameter were found. Spectroscopic measurements of polymer fragments and microguidewires identified various polymers.

CONCLUSION

Backloading of polymer-coated microguidewires during EVT should be minimized if possible. More stable hydrophilic coatings on microguidewires and less traumatic insertion tools are desirable.

Non-ischemic cerebral enhancing lesions after thrombectomy: a multicentric retrospective French national registry

To report the occurrence of non-ischemic cerebral enhancing (NICE) lesions following mechanical thrombectomy (MT) through the retrospective French nationwide registry of NICE lesions. All thrombectomy capable stroke centers (TSC) in France were invited to fill out a questionnaire disseminated through a trainee-led research network (JENI-RC: Jeunes en Neuroradiologie Interventionnelle-Research Collaborative). NICE lesions were defined according to previous literature as delayed onset punctate, nodular, or annular foci enhancements with peri-lesion edema and vascular distribution in the territory of the MT with no other confounding disease. All 43 TSC French centers responded. Three patients were reported by 3 different centers over a total of 34,824 MT (2015-2020). Patient no. 1 developed symptomatic NICE lesions 8 weeks after MT with combination of aspiration and stentriever for a right middle cerebral artery occlusion. Patient no. 2 developed asymptomatic NICE lesions 5 weeks after MT with direct thromboaspiration for a right middle cerebral artery occlusion. Patient no. 3 developed symptomatic NICE lesions 6 weeks after MT with direct thromboaspiration, and combination of aspiration and stentriever for a basilar artery occlusion. This study provides evidence that NICE lesions following MT are a possible rare complication with a similar presentation as previously described following endovascular aneurysm treatment. Both radiologists and neurologists should be aware of this adverse event and make use of MRI contrast agents in case of unexplained symptoms/images during follow-up after MT.

Incidence, clinical spectrum, and immunotherapy of non-ischemic cerebral enhancing lesions after endovascular therapy

Background:

Symptomatic and asymptomatic delayed non-ischemic cerebral enhancing (NICE) lesions in magnetic resonance imaging (MRI) have been reported as a rare complication after endovascular therapy (EVT) in recent years with incidence rates between 0.05% and 0.9% in most studies. Information on long-term clinical course and immunotherapies is scarce or has not been reported in detail in the literature. Objective: Aims of our study were to assess the incidence of NICE lesions in patients after cerebral EVT over a period of more than 12 years, describe clinical and EVT characteristics, and immunotherapies applied.

Methods:

A retrospective chart review of all patients treated by endovascular therapy for symptomatic or asymptomatic aneurysms at the University Hospital of Augsburg from May 1, 2008 to December 31, 2020 was performed. Patients were identified retrospectively and followed-up prospectively where appropriate. In addition, one case treated at another institution was included.

Results:

Five out of 746 patients, 0.67%, developed NICE lesions after EVT, all with non-ruptured aneurysms and all symptomatic upon detection of NICE lesions by MRI. In total, the disease course of 6 female patients is reported. Symptoms occurred after a mean time of 15 days (±13.42, SD) after EVT with headache (6/6 patients), focal neurological signs (6/6 patients), epileptic seizures (2/6 patients) and cognitive deficits (3/6 patients). All 6 patients received glucocorticosteroids (GCS), 1/6 azathioprine (AZA), 4/6 mycophenolate mofetil (MMF), 1/6 methotrexate (MTX), 1/6 rituximab (RTX), 2/6 cyclophosphamide (CYC) and 3/6 tocilizumab (TCZ). A treatment response could be observed for GCS, TCZ and MMF (in two of four cases), RTX and AZA did not result in disease stabilization.

Conclusions:

Delayed NICE lesions are a rare complication after EVT, requiring immunotherapies in all patients reported here. Physicians should be aware of this disorder in case of new symptoms or contrast enhancing lesions after EVT.

Delayed Leukoencephalopathy and Foreign Body Reaction After Endovascular Treatment in Patients With Intracranial Aneurysms and Aneurysmal Subarachnoid Hemorrhage-A Systematic Review of the Literature

Background: Delayed leukoencephalopathy and foreign body reaction are rare complications after endovascular treatment of intracranial aneurysms. However, cases are increasingly being described, given the rising case numbers and complexity.

Methods: Clinical presentation, differentials, diagnostics, treatment, and formerly published data were reviewed in light of available cases. A systematic search of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

Results: This article provides an extensive literature review of previously described cases, and discusses the causes and management of this rare and delayed complication by referring to 17 articles on this topic, with a total of 50 cases with sufficient data in the literature. Furthermore, we present the case of a 53-year-old female patient with subarachnoid hemorrhage from a large anterior communicating artery aneurysm with tortuous cervical vessels who was treated with endovascular coiling and has suffered delayed leukoencephalopathy 6 weeks after discharge. Diagnostics, treatment, and clinical course of this rare complication are presented on this case and based on formerly published literature. The patient timely recovered under high dose corticosteroid treatment and follow up MRI showed almost complete remission of the described lesions within 10 days in accordance with previously published data.

Conclusion: Foreign body reaction might result in delayed leukoencephalopathy, especially following complex endovascular aneurysm treatment. Early high dose followed by low dose ongoing corticosteroid treatment might result in timely remission.

Hydrophilic Polymer Embolism: Implications for Manufacturing, Regulation, and Postmarket Surveillance of Coated Intravascular Medical Devices

ABSTRACT

Hydrophilic polymers are ubiquitously applied as surface coatings on catheters and intravascular medical technologies. Recent clinical literature has heightened awareness on the complication of hydrophilic polymer embolism, the phenomenon wherein polymer coating layers separate from catheter and device surfaces, and may be affiliated with a range of unanticipated adverse reactions. Significant system barriers have limited and delayed reporting on this iatrogenic complication, the full effects of which remain underrecognized by healthcare providers and manufacturers of various branded devices. In 2015, the United States Food and Drug Administration acknowledged rising clinical concerns and stated that the agency would work with stakeholders to further evaluate gaps that exist in current national and international device standards for coated intravascular medical technologies. The present article reviews current knowledge on this complication as well as factors that played a role in delaying detection and dissemination of information and new knowledge once hazards and clinical risks were identified. Furthermore, organ-specific effects and adverse reaction patterns are summarized, along with implications for device manufacturing, safety assurance, and regulation. Qualitative and quantitative particulate testing are needed to optimize coated intravascular device technologies. Moreover, general enhanced processes for medical device surveillance are required for timely adverse event management and to ensure patient safety.

Non-ischemic cerebral enhancing lesions after intracranial aneurysm endovascular repair: a retrospective French national registry

BACKGROUND

Non-ischemic cerebral enhancing (NICE) lesions are exceptionally rare following aneurysm endovascular therapy (EVT).

OBJECTIVE

To investigate the presenting features and longitudinal follow-up of patients with NICE lesions following aneurysm EVT.

METHODS

Patients included in a retrospective national multicentre inception cohort were analysed. NICE lesions were defined, using MRI, as delayed onset punctate, nodular or annular foci enhancements with peri-lesion edema, distributed in the vascular territory of the aneurysm EVT, with no other confounding disease.

RESULTS

From a pool of 58 815 aneurysm endovascular treatment procedures during the study sampling period (2006-2019), 21/37 centres identified 31 patients with 32 aneurysms of the anterior circulation who developed NICE lesions (mean age 45±10 years). Mean delay to diagnosis was 5±9 months, with onset occurring a month or less after the index EVT procedure in 10 out of 31 patients (32%). NICE lesions were symptomatic at time of onset in 23 of 31 patients (74%). After a mean follow-up of 25±26 months, 25 patients (81%) were asymptomatic or minimally symptomatic without disability (modified Rankin Scale (mRS) score 0-1) at last follow-up while 4 (13%) presented with mild disability (mRS score 2). Clinical follow-up data were unavailable for two patients. Follow-up MRI (available in 27 patients; mean time interval after onset of 22±22 months) demonstrated persistent enhancement in 71% of cases.

CONCLUSIONS

The clinical spectrum of NICE lesions following aneurysm EVT therapy spans a wide range of neurological symptoms. Clinical course is most commonly benign, although persistent long-term enhancement is frequent.

Delayed Multiple Non-ischemic Cerebral Enhanced Lesions After Endovascular Therapy For Left Internal Carotid Aneurysm: A Case Report

INTRODUCTION

Endovascular therapy (EVT) for intracranial arterial aneurysms is depicted with several complications. Very recently, delayed non-ischemic cerebral enhanced (NICE) lesions have been identified as a rare complication associated with EVT. This complication always stands a higher chance of being missed in asymptomatic patients. We report a case of multiple NICE lesions in a known chronic hepatitis B infection and chronic gastritis patient with left internal carotid aneurysm (ICA) treated with detachable coils.

CASE PRESENTATION

A 52 years old female with left ICA was treated with detachable coils via the endovascular route. Three weeks after the operation, she presented with numbness of her right limbs which was persistent and waked her up from sleep each night. She admitted skin allergies after wearing metals except for gold and silver since childhood. MRI revealed multiple abnormal lesions in the left temporal lobe, hippocampus, insula, and parietal lobe and some perifocal edema which were consistent with the diagnosis of delayed NICE lesions.

CONCLUSION

It is very important to report the occurrences of these lesions in literature because of their allergic origin. We advocate that allergy to metals especially those used in coating endovascular equipment should be evaluated before every EVT for intracranial aneurysms.

Hydrophilic polymer embolization following flow diversion of cerebral aneurysms

Foreign body embolization is a rare and potentially under-recognized complication of neuroendovascular procedures. This complication should be considered in the differential diagnosis for clinical or radiological deterioration following neurovascular interventions. We report a case of foreign body hydrophilic coating embolization that occurred following an attempted flow diversion of an intracranial aneurysm with dramatic flare-up after repeat exposure. We also provide a literature review of all reported cases of hydrophilic polymer embolization following flow diversion procedures.

Medical treatment of polymeric cerebral granulomatous reactions following endovascular procedures

BACKGROUND

Endovascular procedures are standard of care for an increasing range of cerebrovascular diseases. Many endovascular devices contain plastic and are coated with a hydrophilic polymer which has been rarely described to embolize, resulting in distal granulomatous inflammatory lesions within the vascular territory.

METHODS

We reviewed three cases of cerebral granulomatous reactions that occurred after endovascular intervention for internal carotid aneurysms. The patient procedure details, presentation, relevant investigations, and treatment course are described. We also provide a literature review on endovascular granulomatous reactions.

RESULTS

These three cases represent the largest biopsy proven series of cerebral granulomatosis following endovascular intervention. We highlight the variable clinical presentation, with two of the three cases having an unusually delayed onset of up to 4 years following the intervention. We show the characteristic histological findings of granulomatous lesions with foreign body material consistent with a type IV reaction, radiological abnormalities of enhancing lesions within the vascular territory of the intervention, and the requirement of prolonged immunosuppression for maintenance of clinical remission, with two of the three patients requiring a corticosteroid sparing agent. In comparison with the available literature, in addition to hydrophilic gel polymer, we discuss that plastic from the lining of the envoy catheter may be a source of embolic material. We also discuss the recommendations of the Food and Drug Administration and the implementation of novel biomaterials for the prevention of these reactions in the future.

CONCLUSIONS

There is a need for increased awareness of this severe complication of cerebral endovascular procedures and further longitudinal studies of its prevalence, optimal management and preventative measures.

Symptomatic intracranial embolic foreign-body reactions after endovascular neurointerventional procedures: A retrospective study in a tertiary hospital

INTRODUCTION

Polymer-coats may peel-off the surface of catheters and devices during endovascular procedures and might lead to brain inflammatory foreign-body reactions.

METHODS

We conducted a retrospective, descriptive, single-centre study including all patients with symptomatic intracranial oedematous and contrast-enhancing lesions after any neurointerventional procedure performed in our hospital between 2013 and 2019.

RESULTS

From a total of 7446 neurointerventional procedures, 11 cases were identified (9 female, 2 male, median age 47 year-old), with an incidence of 0.14 %. The procedures were therapeutic in all: ten aneurysm embolization/isolation, one acute ischaemic stroke recanalization. Intracranial coils, stent or both were placed in all. Symptoms appeared during the following one day to fourteen months (median of 4.2 weeks). Brain MRI showed oedematous, contrast-enhancing lesions scattered through the vascular territory of the canalized vessel. Brain biopsy confirmed the diagnosis in one case and was supportive in another one. Eight patients received immunosuppression. No treatment was started in two. After a median time of follow-up of 3.5 years, five patients are totally asymptomatic. One patient presents slight weakness. Four patients have remote symptomatic seizures, but they have comorbid lesions (previous stroke, intracranial haemorrhage, biopsy needle-track's gliosis). Follow-up MRI showed significant improvement in all the cases, with complete resolution in five. Non-symptomatic lesion fluctuation was observed in three cases. Two patients experienced symptomatic rebounds.

CONCLUSION

Intracranial embolic foreign-body symptomatic reactions are uncommon complications of neurointerventional procedures. Diagnostic angiographies might have lower risk of polymer-embolization than therapeutic procedures. This entity's early recognition enables making proper diagnosis and treatment decisions.

Immunomodulatory property and its regulatory mechanism of double network hydrogel on dendritic cells

Modulation of the key immune cell subsets by biomaterial has emerged as a potential target to promote tissue repair and regeneration. Based on calcium alginate (Alg) and glycol chitosan (GC), an injectable double-network (DN) hydrogel has been developed as a scaffold for cell delivery and cell cocultured system. Previous studies have documented the interaction between dendritic cells (DCs) and GC or Alg hydrogel, but the potential effect of DN hydrogel on activation of DCs still remains unclear. This research was conducted to explore the immunomodulatory influence and underlying mechanisms of GC/Alg DN hydrogel on DCs in vitro and in vivo. Stimulation of DCs with DN hydrogel obviously induced the maturation of DCs in vitro. In vivo, DN hydrogel did not have obvious influence on the maturation of splenic DCs on postimplantation days 3, 10, and 30. Mechanistically, we found that DN hydrogel induced the maturation of DCs via phosphorylation of phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin in vitro. It provides a novel understanding of the immunomodulatory property of DN hydrogel on DCs, which may serve as potential target for designing immune-mediated regenerative strategies.

Is CD47 a potentially promising therapeutic target in cardiovascular diseases? - Role of CD47 in cardiovascular diseases

CD47 (cluster of differentiation 47) is a ubiquitously expressed transmembrane protein that belongs to the immunoglobulin superfamily. CD47 is both a receptor for the matricellular protein thrombospondin-1 (TSP-1) and a ligand for signal-regulatory protein alpha (SIRPα). Suppression of CD47 activity enhances angiogenesis and blood flow, restores phagocytosis by macrophages, improves ischemic tissue survival, attenuates ischemia reperfusion injury, and reverses atherosclerotic plaque formation. In conclusion, these observations suggest a pathogenic role of CD47 in the development of cardiovascular diseases (CVDs) and indicate that CD47 might be a potentially promising molecular target for treating CVDs. Herein, we highlight the role of CD47 in the CVD pathogenesis and discuss the potential clinical application by targeting CD47 for treating CVDs.

Headache and MRI Changes after Endovascular Treatment of a Cerebral Aneurysm

Background

The main complications after endovascular therapy of intracranial aneurysms are aneurysm rupture and thromboembolic events. Yet, the widespread use of magnetic resonance imaging (MRI) in follow-up of these patients also demonstrates other, rarely known complications such as aseptic meningitis and foreign body reaction.

Case Presentation

A small aneurysm in the right posterior communicating artery was treated with endovascular therapy in a 65 year old woman. Two weeks after successful interventional treatment, the patient developed a headache. On MRI performed five months after intervention, vasogenic edema was seen in the vascular territory of the right internal carotid artery. The edema and the symptoms diminished without specific treatment within a year.

Interpretation

The clinical and radiological presentation of this case are suggestive of a foreign body reaction, a treatable condition that radiologists and clinicians should be aware of.

Delayed Intracranial Parenchymal Changes After Aneurysmal Coil Embolization Procedures for Unruptured Intracranial Aneurysms

BACKGROUND

With the recent advances in endovascular treatment devices, it has become standard in wide-neck or large intracranial aneurysms to perform coil embolization with adjunctive techniques. However, device-related perioperative complications have been reported because of the use of more complex systems.

OBJECTIVE

To investigate patients who developed multiple parenchymal lesions after undergoing coil embolization for treating an unruptured intracranial aneurysm.

METHODS

This study investigated 305 consecutive patients who underwent coil embolization of unruptured intracranial aneurysms between 2015 and 2017. Delayed inflammatory changes referred to the delayed observation of multiple cerebral white matter lesions on follow-up magnetic resonance imaging at an area corresponding to the perfused area of the treatment target vessel. The timing and pattern of onset, device used, the combined use of adjunctive techniques, and the clinical course after steroid treatment were retrospectively investigated.

RESULTS

The 7 patients (2.3%) who showed delayed inflammatory changes were all women with a mean age of 59 yr. A mean duration from treatment to onset was 28 d. Symptoms were convulsions in 3 patients, hemiplegia in 2 patients, and homonymous hemianopia in 1 patient. All 7 patients were treated with adjunctive technique including stents, double catheter method, and balloon assist. Response to steroid treatment was satisfactory both clinically and on imaging in all 7 patients. Skin patch test was positive for nickel allergy in 2 patients.

CONCLUSION

Clinicians must be fully aware of symptomatic delayed inflammatory changes may occur after endovascular aneurysmal treatment with the use of various devices.

Intrathrombus polymer coating deposition: a pilot study of 91 patients undergoing endovascular therapy for acute large vessel stroke. Part I: Histologic frequency

BACKGROUND

Polymer coating embolism due to vascular medical device use is an increasingly recognized iatrogenic complication. This phenomenon has been linked with various adverse effects including neuroinflammation, acute ischemic stroke, cerebral hemorrhage, and death. Notably, procedure- and device-specific risks of this complication are poorly investigated. In this study, we evaluate the detectable frequency of intra-arterial polymer coating delamination among patients who underwent endovascular thrombectomy for treatment of acute ischemic stroke due to large vessel occlusion.

METHODS

Ninety-two cerebral thrombectomy specimens were retrospectively analyzed for the presence of polymer coating particulates. Histologic findings were correlated with demographic and procedural details and patient outcomes.

RESULTS

Evidence of polymer coating deposition was found in 30 of 92 extracted thrombi (33%). No correlation between intrathrombus polymer deposition and use of a specific thrombectomy device such as a stent retriever, aspiration catheter, or guide catheter was found. However, heterogeneous patterns of device use suggest a number of culprit devices. A trend toward longer procedure times and multiple thrombectomy passes was noted in positive cases. Intrathrombus polymer deposition was not associated with adverse clinical outcomes as measured by the 90-day modified Rankin Scale (mRS); however, small sample size and follow-up intervals limit interpretation. Ninety-day outcomes based on mRS may not fully capture the clinical effects of acute and/or delayed intracerebral polymer complications.

CONCLUSION

In light of documented adverse neurologic effects, the frequency of intrathrombus polymer particulates indicates the need for consensus testing methods and large-scale long-term prospective clinical device trials, with inclusion of relevant endpoints to better assess biomaterial and device risks to patients.

Cerebral foreign body reaction due to hydrophilic polymer embolization following aneurysm treatment by pipeline flow diversion device

The use of flow diverting stents for wide based, intracranial aneurysms has become an invaluable treatment option. While intracranial hemorrhage and ischemic stroke from dislodged atherosclerotic emboli are common adverse events, the potential for delayed granulomatous inflammation from possible hydrophilic polymer emboli is rarely recognized. We present a unique case in which visible chipping of the pusher wire for stent placement was observed, followed by clinical and radiographic evidence suggestive of a delayed foreign body reaction to intracranial hydrophilic polymer emboli. A 55-year-old woman underwent placement of a Pipeline embolization device for a left-sided, broad-based aneurysm at the base of the internal carotid artery and posterior communicating artery. Two months later she developed right-sided focal neurological deficits. Imaging showed ipsilateral focal edema and enhancing lesions with contrast. Although not confirmed with biopsy and histopathology, clinical and radiographic evidence suggests that this patient probably experienced a delayed foreign body reaction to hydrophilic polymer emboli from compromised procedural equipment during flow diverting stent placement. Although previously described, this is the first instance to our knowledge in whichvisible chipping of the pusher wire was observed on a Pipeline embolization device.

Testing bioresorbable stent feasibility in a rat aneurysm model

Background

Advances in stent-assisted coiling have incrementally expanded endovascular treatment options for complex cerebral aneurysms. After successful coil consolidation and aneurysm occlusion, endovascular scaffolds are no longer needed. Thus, bioresorbable stents that disappear after aneurysm healing could avoid future risks of in-stent thrombosis and the need for lifelong antiplatelet therapy.

Objective

To assess the applicability and compatibility of a bioresorbable magnesium- alloy stent (brMAS) for assisted coiling.

Methods

Saccular sidewall aneurysms were created in 84 male Wistar rats and treated with brMAS alone, brMAS + aspirin, or brMAS + coils + aspirin. Control groups included no treatment (natural course), solely aspirin treatment, or conventional cobalt–chromium stent + coils + aspirin treatment. After 1 and 4 weeks, aneurysm specimens were harvested and macroscopically, histologically, and molecularly examined for healing, parent artery perfusion status, and inflammatory reactions. Stent degradation was monitored for up to 6 months with micro-computed and optical coherence tomography.

Results

Aneurysms treated with brMAS showed advanced healing, neointima formation, and subsequent stent degradation. Additional administration of aspirin sustained aneurysm healing while reducing stent-induced intraluminal and periadventitial inflammatory responses. No negative interaction was detected between platinum coils and brMAS. Progressive brMAS degradation was confirmed.

Conclusions

brMAS induced appropriate healing in this sidewall aneurysm model. The concept of using bioresorbable materials to promote complete aneurysm healing and subsequent stent degradation seems promising. These results should encourage further device refinements and clinical evaluation of this treatment strategy for cerebrovascular aneurysms.

Efficiency and complications of Woven EndoBridge (WEB) devices for treatment of larger, complex intracranial aneurysms-a single-center experience

BACKGROUND

Several recently published multicenter studies have reported high treatment feasibility, high safety, and good 6-month to 1-year efficiency when treating smaller intracranial aneurysms (IA) with WEB deployment. The purpose of the study was to evaluate the long-term efficiency and complications related to WEB treatment of larger, complex intracranial aneurysms in a small single-center cohort.

METHODS

Patients with ruptured and unruptured IA were treated with WEB devices; data were collected prospectively and analyzed retrospectively. The study evaluates complications and clinical and radiological findings at immediate and last available follow-up.

RESULTS

The study included 16 patients with 16 aneurysms and a median follow-up time of 36 months, range 13-49 months; 9/16 were females. Median age 59 with range 39-71 years. Mean aneurysm size 11.3 ± 1.7 mm, predominant location at the basilar artery bifurcation and anterior communicating artery. Three out of sixteen IAs were ruptured. Even though 75% of the IAs were immediately occluded completely, retreatment was eventually necessary in 7/15 (46.7%). Increasing neck remnants and recurrences were mainly observed past 1-year follow-up. The WEB device showed modifications over time, with six devices showing signs of compression in the long term. There was one fatality due to aneurysm rupture after 4 years.

CONCLUSIONS

The long-term efficiency of WEB deployment in larger, complex aneurysms is low with about half of the cases needing at least one retreatment. A large fraction of WEB collapse past 1-year follow-up.

Delayed leucoencephalopathy after coil embolisation of unruptured cerebral aneurysm

A 56-year-old right-handed woman was successfully treated by coil embolisation for a large unruptured paraclinoid aneurysm of the left internal carotid artery. Though she was discharged on day 3 after the intervention with uneventful clinical course, she was rehospitalised for continuous headache and right upper limb weakness 2 weeks after the treatment. Subsequent progression of cognitive dysfunction and right hemiparesis were observed. Repeated MRI revealed diffuse leucoencephalopathy within the ipsilateral brain hemisphere. Clinical course, serological examination, and radiological findings were consistent with localised hypocomplemental vasculitis caused by delayed hypersensitivity reaction. Immunosuppressive treatments using prednisolone successfully improved her symptoms. After a washout period for immunosuppressant, skin reaction test was performed and revealed polyglycolic-polylactic acid, coating material of the coil, positive for delayed allergic reaction. Given the increased frequency of endovascular treatment for unruptured aneurysms, even such a rare complication should be recognised and treated properly to avoid neurological sequelae.

Delayed neurological deficits after endovascular placement of a pipeline embolisation device: clinical manifestation and treatment

Endovascular treatment has been the mainstay of therapy for repair of both ruptured and unruptured cerebral aneurysms. Flow diverter devices offer a new option for the treatment of complex aneurysms that were previously not amenable to coiling. Procedural adverse effects include intracranial haemorrhage and ischaemic stroke, which usually occur on the same day. Delayed complications are rare. We report a case of a patient who underwent placement of a pipeline embolisation device and developed delayed neurological deficits, which were thought to be an inflammatory reaction to the hydrophilic coating used in guidewires and microcatheters. Our patient was treated with a course of steroids, with improvement of her neurological deficits and resolution of MRI findings. As the use of flow diverter devices has increased, variable and delayed complications of such therapy are increasingly being reported in the literature.

Cerebral Granulomatous Inflammation Secondary to Hydrophilic Polymer Embolization Following Thrombectomy

BACKGROUND Given the recent completion of multiple trials demonstrating the benefit of endovascular mechanical thrombectomy for select patients with proximal large artery occlusive ischemic strokes, there has been a large increase in the performance of these procedures. In the context of increased thrombectomy performance, there have also been increased reports of rare occurrences of granulomatous inflammatory response to the hydrophilic polymer which coat many of these interventional devices. CASE REPORT A 59-year-old female presented with a complete occlusion of her right proximal middle cerebral artery (MCA) and imaging showed a large area of penumbra. Cerebral angiogram and mechanical thrombectomy were successfully performed with reversal of clinical symptoms. Eight months following her stroke, she developed progressive recurrence of left-sided neurological deficits. After extensive workup culminating in tissue sampling, she was found to have developed granulomatous inflammation surrounding microscopic embolization of hydrophilic polymer, which is used to coat many interventional devices such as wires and catheters. The patient responded both clinically and radiographically to anti-inflammatory steroid therapy. CONCLUSIONS Recognizing the significant potential morbidity of a large vessel ischemic stroke and the expanded use of endovascular interventions aimed at staving off this disability, there are emerging and at times indolent complications from the use of hydrophilic polymer coated wires and catheters. This rare and potentially under-recognized complication should be considered in the differential for any patient with new neurological findings following cerebral intervention, especially given the consideration that this appears to a treatable complication.

Polymer-induced central nervous system complications following vascular procedures: spectrum of iatrogenic injuries and review of outcomes

Polymer substances are commonly applied as surface coatings on endovascular catheters and vascular devices. Adverse effects related to their use have been reported, although the overall clinical significance and appropriate methods of detection of these complications have been unclear. In this analysis, we systematically reviewed clinical and diagnostic features in 32 patients (age, 36-87years; mean, 59years) in whom intracranial polymer reactions were documented following vascular interventions. Associated neuroradiologic and neuropathologic findings were variable and included cerebral vasculitis or vasculopathy (63%), abscess or granuloma formation (38%), ischemic infarcts (28%), parenchymal hematomas (28%), white matter change (25%), and/or chemical meningitis (22%). Location(s) of polymer reactions varied and included sites adjacent to and/or downstream from instrument insertion or implantation. Presenting clinical signs included focal neurologic deficits (41%), headache (22%), constitutional symptoms (19%), meningitis (16%), seizure and/or involuntary movements (9%), coma (6%), and syncope (3%). Adverse outcomes included stroke (31%), death (28%), delayed communicating hydrocephalus (9%), steroid dependency (9%), steroid complications (6%), and cerebral volume loss (3%). In some cases, these complications necessitated increased cost and length of medical care. In this review, we highlight the diverse features of polymer-induced reactions involving the central nervous system and summarize distinct diagnostic patterns that may enable earlier premortem detection of these lesions in the postprocedural clinical setting. Further work in this area is necessary to identify additional etiologic, preventative and therapeutic strategies. These data have potentially broad implications pertaining to the safety, efficacy, standards of use, storage, manufacturing, and regulation of new and emerging vascular devices and polymer nanotechnologies.