Pipeline Embolization Device Research Articles

Difference in the cumulative incidence of aneurysmal occlusion by Flow Re-direction Endoluminal Device and Pipeline Embolization Device in the treatment of unruptured internal carotid artery aneurysms: a propensity score-matched cohort study.

The introduction of flow diverters (FDs) has represented a paradigm shift in the management of unruptured cerebral aneurysms (UCA). Flow Re-direction Endoluminal Devices (FREDs) and Pipeline Embolization Devices (PEDs) have gained widespread popularity. We aimed to investigate the cumulative incidence of aneurysm occlusion. A total of 195 patients with 199 UCAs were analyzed retrospectively. The outcomes were aneurysmal occlusion during the follow-up, a modified Rankin Scale score of 0-2 at 90days, additional treatment, major stroke, and steno-occlusive events of FD. Propensity score-matched analysis was performed, controlling for age, sex, aneurysmal size, and location of the internal carotid artery (ICA) aneurysm. Non-ICA aneurysms were excluded from matching. During the follow-up period (median, 366days), complete and satisfactory aneurysmal occlusions were observed in 128 (68%) and 148 (78%) of 189 UCAs in the unmatched cohort. The 142 (71 each) propensity score-matched cohort was complied. The FRED group had a higher cumulative incidence of ICA aneurysm occlusion (complete: HR 2.7, 95% CI 1.4-5.1, p = 0.0025; satisfactory: HR 2.4, 95% CI 1.1-5.2, p = 0.025). The proportion of additional treatment was significantly smaller in the FRED group (OR 0.077, 95% CI 0.010-0.57, p = 0.0007). Other outcomes showed no significant differences. Propensity score-matched analysis indicated that FRED might have a higher cumulative incidence of aneurysmal occlusion in the treatment of unruptured ICA aneurysms. Whether a cumulative incidence of aneurysmal occlusion may differ by the type of FDs warrants further investigation.

Effect of Statin on Radiographic and Clinical Outcomes of Intracranial Aneurysms Treated With Pipeline Embolization: A Propensity Score-Matched Analysis.

Studies have shown that use of statin can improve radiographic and clinical outcomes in patients receiving treatment for coronary artery or peripheral vascular stenosis. Statins are thought to be effective by reducing arterial wall inflammation. The same mechanism may have an influence on the efficacy of pipeline embolization device (PED) for intracranial aneurysm treatment. Although this question has been of interest, there is a lack of well-controlled data in the literature. The objective of this study is to analyze the effect of statins on outcomes of aneurysms treated with pipeline embolization through propensity score matching. Patients who underwent PED for unruptured intracranial aneurysms at our institution between 2013 and 2020 were identified. Patients on statin treatment vs those who were not were matched through propensity score by controlling for confounding factors including age, sex, current smoking status, diabetes, aneurysm morphology, volume, neck size, location of aneurysm, history of treatment for the same aneurysm, type of antiplatelet therapy, and elapsed time at last follow-up. Occlusion status at first follow up and last follow-up, and incidence of in-stent stenosis and ischemic complications during the follow-up period were extracted for comparison. In total, 492 patients with PED were identified, of whom 146 were on statin therapy and 346 were not. After one-to-one nearest neighbor matching, 49 cases in each group were compared. At last follow-up, 79.6%, 10.2%, and 10.2% of cases in the statin therapy group and 67.4%, 16.3%, and 16.3% in the nonstatin group were noted to have Raymond-Roy 1, 2, and 3 occlusions, respectively ( P = .45). No significant difference was observed in immediate procedural thrombosis ( P > .99), long-term in-stent stenosis ( P > .99), ischemic stroke ( P = .62), or retreatment ( P = .49). Statin use does not affect occlusion rate or clinical outcomes in patients treated with PED treatment for unruptured intracranial aneurysms.

Pipeline embolization device versus Atlas stent assisted coiling for intracranial aneurysm treatment: a retrospective, propensity score matched study with a focus on midterm outcomes and hospital costs

BackgroundStent assisted coiling (SAC) and flow diverters (FDs) are common endovascular treatments for wide necked cerebral aneurysms, but studies comparing the new generation Atlas SAC and FDs are scarce. We...

Letter: Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video.

To the Editor: We read with great interest the article “Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video” by Hackett et al.1 The authors present a case of a patient with an arteria lusoria who received effective flow-diverting stent therapy for a large left internal carotid artery (ICA) aneurysm using a large bore guide catheter through right transradial access (TRA). Diagnostic angiography showed that the left ICA could be accessed through the right TRA. A 6F radial sheath was introduced into the right radial artery, and the sheath was then exchanged over a 0.035″ guidewire for an 8F 90-cm guide catheter (Infinity; Stryker Neurovascular). After navigating a 5F 130-cm Simmons catheter into the left common carotid artery through the arteria lusoria, the 8F guide catheter was delivered into the left ICA using the telescoping technique. The large left ICA-ophthalmic artery aneurysm was successfully treated with a pipeline embolization device (Medtronic). The importance of evaluating transradial diagnostic angiography to determine whether a catheter system can safely track into the target supra-aortic vessels is critical for successful transradial neurointervention in patients with arteria lusoria, and we wholeheartedly concur with the authors' conclusion on this point. Cannulation into the supra-aortic vessels through right TRA can be extremely challenging in patients with arteria lusoria because of unfavorable catheter trajectory.2 In addition, the right TRA can cause fatal arteria lusoria dissection.3 Therefore, transfemoral access is frequently employed as first-line access if neurointerventionalists encounter arteria lusoria.2 Previous study reported that left TRA is a technically feasible alternative in neurointerventions for patients with arteria lusoria.4 Nevertheless, a guide catheter may result in a failed TRA that necessitates a crossover to transfemoral access because of a failed cannulation, a kinked catheter, or an unstable system. We have used transradial access as the first-line access for neurointerventions.5-18 The first-line TRA using a 6F preshaped Simmons guiding sheath (outer diameter, 2.70 mm; inner diameter, 0.088″; usable length, 90 cm; 6F Axcelguide Stiff-J; Medikit) offers a large bore working channel and a high procedural success rate without catheter kinking or system instability even in patients with an unfavorable steep supra-aortic take-off.5-7,13 The 6F Simmons guiding sheath is fully engaged into the target common carotid artery with a pull-back maneuver (the pull-back technique) after reforming the Simmons curve within the ascending aorta. The Simmons curve can be reformed by anchoring the 6F Simmons guiding sheath to the descending aorta (the descending aorta anchoring technique) or contralateral subclavian artery (the subclavian artery anchoring technique) through the left TRA. Transradial carotid cannulation with the pull-back technique is technically simple and promising. As a result, left TRA with the 6F Simmons guiding sheath can be a beneficial treatment choice for performing anterior circulation procedures in patients with arteria lusoria. Finally, we would like to express our appreciation to the authors for their interesting article that advances the transradial neurointerventional method.

Long-term outcomes following pipeline embolization of unruptured aneurysms.

Flow diversion using the pipeline embolization device (PED) for unruptured aneurysms is associated with high occlusion and low morbidity and mortality. However, most reports have limited follow-up of 1-2 years. Therefore, we sought to report our outcomes after PED for unruptured aneurysms in patients with at least 5-years of follow-up. Review of patients undergoing PED for unruptured aneurysms from 2009 to 2016. Overall, 135 patients with 138 aneurysms were included for analysis. Seventy-eight percent of aneurysms (n=107) over a median radiographic follow-up of 5.0 years underwent complete occlusion. Among aneurysms with at least 5-years of radiographic follow-up (n=71), 79% (n=56) achieved complete obliteration. No aneurysm recanalized after radiographic obliteration. Furthermore, over a median clinical follow-up period of 4.9 years, 84% of patients (n=115) self-reported mRS scores between 0 and 2. For patients with at least 5-years of clinical follow-up, 88% (n=61) reported mRS between 0 and 2. In total, 3% (n=4) of patients experienced a major, non-fatal neurologic complication related to the PED, 5% (n=7) of patients experienced a minor neurologic complication related to PED placement, and 2% (n=3) died from either delayed aneurysm rupture, delayed ipsilateral hemorrhage after PED placement, or delayed (9 months after treatment) neural compression after progressive thrombosis of a PED-treated dolichoectactic vertebrobasilar aneurysm. Treatment of unruptured aneurysms with the PED is associated with high rates of long-term angiographic occlusion and low, albeit clinically important, rates of major neurologic morbidity and mortality. Thus, flow diversion via PED placement is safe, effective, and durable.

Morphological features predicting in-stent stenosis after pipeline implantation for unruptured intracranial aneurysm.

Elongation denotes the regularity of an aneurysm and parent artery. This retrospective research study was conducted to identify the morphological factors that could predict postoperative in-stent stenosis (ISS) after Pipeline Embolization Device (PED) implantation for unruptured intracranial aneurysms (UIAs). Patients with UIA and treated with PED at our institute between 2015 and 2020 were selected. Preoperative morphological features including both manually measured shape features and radiomics shape features were extracted and compared between patients with and without ISS. Logistic regression analysis was performed for factors associated with postoperative ISS. A total of 52 patients (18 men and 34 women) were involved in this study. The mean angiographic follow-up time was 11.87 ± 8.26 months. Of the patients, 20 of them (38.46%) were identified with ISS. Multivariate logistic analysis showed that elongation (odds ratio = 0.008; 95% confidence interval, 0.001-0.255; p = 0.006) was an independent risk factor for ISS. The area under the curve (AUC) of the receiver operating characteristic curve(ROC) was 0.734 and the optimal cut-off value of elongation for ISS classification was 0.595. The sensitivity and specificity of prediction were 0.6 and 0.781, respectively. The ISS degree of elongation of less than 0.595 was larger than the ISS degree of elongation of more than 0.595. Elongation is a potential risk factor associated with ISS after PED implantation for UIAs. The more regular an aneurysm and parent artery, the less likelihood of an ISS occurrence.

Patch Technique for Primary Treatment of Type A Carotid Cavernous Fistula: A Case Series and Technical Notes.

The utilization of flow diverters (FDs) in the treatment of high-flow Type A carotid cavernous fistulas (CCFs) has been described before mainly as an adjunct to the traditional endovascular techniques and rarely as a stand-alone treatment. In this study, we retrospectively evaluated our experience with FDs as the solo nonadjunctive treatment of Type A CCF with severe cortical venous reflux (CVR). A retrospective review was performed of patients with Type A CCFs who were treated using FDs' patch technique (PT). Patients' demographics, clinical data, and preoperative and postoperative ocular examination were recorded. The procedure technique, pipeline embolization device (PED) diameters, and immediate and late procedure outcomes were described. Three patients were included in this case series. All patients had history of trauma and presented with decreased visual acuity, cranial nerve II deficit, limited extraocular muscles' movement, and increased intraocular pressure (IOP). Diagnostic angiography was performed, which confirmed high-flow Type A CCF. Endovascular treatment was performed through distal radial access in 2 patients and femoral access in 1 patient by deploying 4 sequentially enlarging PEDs with immediate resolution of the ocular symptoms. Follow-up angiography confirmed complete resolution of CCF in 2 patients. One patient was lost to follow-up; however, angiogram at 4 months demonstrated residual small CCF with significant improvement from postprocedure angiogram. The patch technique using sequentially enlarging FDs is a reasonable alternative solo technique for the treatment of direct CCF symptoms and results in immediate resolution of CVR while preserving the cavernous sinus anatomy.

The first decade of flow diversion for intracranial aneurysms with the Pipeline embolization device.

Flow diverter devices have revolutionized the treatment of intracranial aneurysms (IAs) since their approval in 2011 and have continued to evolve. The devices have been widely adopted across institutions and centers over the past decade; however, long-term follow-up after treatment with the Pipeline embolization device (PED) is not well described in the literature. The authors' institution was among the first to begin using PEDs, allowing them to report their series of patients treated with flow diverters ≥ 10 years ago. In this study, the authors aimed to evaluate the long-term angiographic and clinical outcomes of these patients and review lessons learned along the way. The authors performed a retrospective review of their institution's IA database from January 2007 to July 2012. All patients with IAs treated with a PED prior to July 2012 were included. Clinical and angiographic characteristics were extracted. Available angiographic follow-up at 1, 3, 5, and 10 years was reported. A total of 83 patients with 92 aneurysms treated with a PED ≥ 10 years ago were identified and included in the study. The mean aneurysm dome diameter was 9.2 (SD 5.7) mm, the mean aneurysm height was 10.4 (SD 6.8) mm, and the mean neck width was 4.1 (SD 2.4) mm. Only 1 (1.1%) aneurysm was ruptured at presentation. Eight (8.7%) aneurysms were recurrences of previous treatment modalities. The morphology was saccular in 77 (83.7%) aneurysms, fusiform in 14 (15.2%), and blister-like in 1 (1.1%). Among saccular aneurysms, 60 (77.9%) were wide-necked. Seventy-five (81.5%) aneurysms were in the internal carotid artery, 12 (13.0%) were vertebrobasilar, 3 (3.3%) were in the middle cerebral artery, and 2 (2.2%) were in the posterior cerebral artery. Angiographic follow-up at 1, 3, 5, and 10 years was available for 75, 59, 50, and 15 patients, respectively. The complete occlusion rates at 1, 3, 5, and 10 years were 94.7%, 96.6%, 96.0%, and 100%, respectively. The retreatment rates at 1, 3, 5, and 10 years were 8.0%, 6.8%, 8.0%, and 6.7%, respectively. The authors provide their single-institution series of IA patients treated with a PED ≥ 10 years ago, with the first report of 10-year follow-up for the available patients.

Flow diversion using the Pipeline embolization device for intracranial and extracranial pseudoaneurysms: a systematic review and meta-analysis of the literature.

Pseudoaneurysms (PSAs) are complex vascular lesions. Flow diversion has been proposed as an alternative treatment to parent artery occlusion that preserves laminar flow. The authors of the present study investigated the safety and short-term (< 1 year) and long-term (≥ 1 year) aneurysm occlusion rates following the treatment of intracranial and extracranial PSAs using the Pipeline embolization device (PED). An electronic database search for full-text English-language articles in Ovid MEDLINE and Epub Ahead of Print, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus was conducted following the PRISMA guidelines. Studies of any design including at least 4 patients with intracranial or extracranial PSAs treated using a PED were included in this analysis. The primary outcome of interest was the rate of peri- and postprocedural complications. Secondarily, the authors analyzed the incidence of complete aneurysm occlusion. A total of 90 patients with 96 PSAs across 9 studies were included. The mean age was 38.2 (SD 15.14) years, and 37.8% of the patients were women. The mean PSA size was 4.9 mm. Most PSAs were unruptured, and the most common etiology was trauma (n = 32, 35.5%), followed by spontaneous formation (n = 21, 23.3%) and iatrogenic injury (n = 19, 21.1%). Among the 51 (53.1%) intracranial and 45 (46.9%) extracranial PSAs were 19 (19.8%) dissecting PSAs. Sixty-six (77.6%) PSAs were in the internal carotid artery and 10 (11.8%) in the vertebral artery. Thirty-three (34.4%) PSAs were treated with ≥ 2 devices, and 8 (8.3%) underwent adjunctive coiling. The mean clinical and angiographic follow-up durations were 10.7 and 12.9 months, respectively. The short-term (< 1 year) and long-term (≥ 1 year) complete occlusion rates were 79% (95% CI 66%-88%, p = 0.82) and 84% (95% CI 70%-92%, p = 0.95), respectively. Complication rates were 8% for iatrogenic dissection (95% CI 3%-16%, p = 0.94), 10% for silent thromboembolism (95% CI 5%-21%, p = 0.77), and 12% for symptomatic thromboembolism (95% CI 6%-23%, p = 0.48). No treatment-related hemorrhage was observed. The overall mortality rate at the last follow-up was 14%. The complete occlusion rate for PSAs treated with the PED was high and increased over time. Although postprocedural complications and mortality were not insignificant, flow diversion represents a reasonably safe option for managing these complex lesions.

Foreign Body Reaction After Endovascular Treatment with Pipeline Embolization Device (P8-5.031)

<h3>Objective:</h3> The following case elucidates a rare complication of a foreign body reaction to the hydrophilic coating fragments of the pipeline embolization device. <h3>Background:</h3> Intracranial aneurysms (IAs) are pathological dilatations of intracranial arteries. Unruptured IAs have a prevalence of 3% in the adult population worldwide. Endovascular treatment (EVT) is a common first line preventive repair for unruptured intracranial aneurysm. <h3>Design/Methods:</h3> NA <h3>Results:</h3> 50-year-old female presented to the ED with acute onset left-sided weakness of the upper and lower extremities and left-sided facial numbness 20 days following treatment of an unruptured anterior communicating artery aneurysm with Pipeline Flex Embolization Device (PED). Patient’s significant medical history includes multiple sclerosis (MS), rheumatoid arthritis, Crohn’s disease managed with Humira, and diabetes. The CT head without contrast showed confluent edema within the right MCA watershed region, suspicious for infarct. However, the CTA of head showed no vessel occlusion with a patent PED. Brain MRI identified numerous enhancing lesions throughout the right cerebral hemisphere with internal cavitations and significant perilesional vasogenic edema with regional mass effect without midline shift. Empiric antibiotics and antifungal were initiated to cover both typical and atypical causes due to Humira use for Crohn’s disease. Labs, blood cultures and CSF results were insignificant. Pulse-dose steroid for 5 days was started, after 72-hr negative blood cultures. Over time, the patient’s symptoms improved, and she regained her strength back. A repeat brain MRI after the course of steroids showed diminished enhancement, size, and number of brain lesions. The patient was discharged home on a long Prednisone taper and long-term intravenous vancomycin, ceftriaxone, and oral metronidazole. <h3>Conclusions:</h3> Foreign body reactions are rare complications of EVT. It is important to be aware of possible foreign body emboli in patients with the enhancing brain lesions located in the same vascular territory where the recent endovascular procedure was performed. <b>Disclosure:</b> Dr. Aung has nothing to disclose. Mr. Kaufman has nothing to disclose. Dr. Moroz has nothing to disclose. Dr. Axelband has nothing to disclose. Mr. Oselkin has nothing to disclose.

The incidence and predictors of in-stent stenosis after pipeline flow-diverter stenting for intracranial aneurysm treatment.

Data on in-stent stenosis (ISS) following the flow diverter (FD) implantation method are scarce and inconsistent. In the present study, we sought to determine the incidence of ISS and identify the factors that predict its severity via the use of ordinal logistic regression. A retrospective review of our center's electronic database was conducted to identify all patients with intracranial aneurysms (IAs) who received pipeline embolization device (PED) implantation between 2016 and 2020. Patient demographics, aneurysm characteristics, procedural information, and clinical and angiographic outcomes were reviewed. ISS was quantitatively assessed on angiographic follow-ups and graded as mild (<25%), moderate (25-50%), or severe (>50%). Ordinal logistic regression was conducted to determine the predictors of stenosis severity. A total of 240 patients with 252 aneurysms treated in 252 procedures were enrolled in this study. ISS has been detected in 135 (53.6%) lesions, with a mean follow-up time of 6.53 ± 3.26 months. The ISS was mild in 66 (48.9%) cases, moderate in 52 (38.5%) cases, and severe in 17 (12.6%) cases. All patients were asymptomatic, except for two of them with severe stenosis who presented with symptoms of acute cerebral thrombosis. Ordinal logistic regression identified that younger age and a longer procedure duration were independent predictors of a higher likelihood of ISS. ISS is a common angiographic finding after PED implantation for IAs and is presented as a largely benign course through long-term follow-up. Patients who were younger in age and had a longer procedure duration were found to be at a greater risk of developing ISS.

565 Delayed Rupture Risk of Persistently Filling Saccular ICA Aneurysms Following Flow Diversion with the Pipeline Embolization Device

INTRODUCTION: Flow diversion of intracranial aneurysms results in high occlusion rates. However, 10-20% of aneurysms remain persistently filling on one year angiography. Often, these are retreated, but risks and benefits of retreatment are not well established. Calculating benefit requires a better understanding of rupture risk of persistently filling flow diverted aneurysms, which is not sufficiently established. METHODS: Our single institution database of 1000 flow diversion cases was queried for persistently filling saccular aneurysms of the clinoidal, ophthalmic, and communicating segments of the internal carotid artery treated with Pipeline Embolization Device or Pipeline Flex. Persistent filling was defined as continued contrast flow into the aneurysm on catheter angiogram one year after treatment. The clinical record was queried for occurrences of retreatment and delayed subarachnoid hemorrhage. Only cases with at least two years of follow up were included. RESULTS: Ninety-four persistent aneurysms were identified. The average size was 6 mm. The branch vessel originated separately from the aneurysm in 55% of cases, from the body of the aneurysm in 10.6% of cases, and from the neck in 34% of cases. Eighteen percent of aneurysms demonstrated &gt;95% filling at one year and 61% were filling 5-95% of their original size. Average follow up time was 4.9 years, including 23 cases with &gt;5 years follow up. No retreatment was undertaken in 91.5% of aneurysms. There were no cases of delayed subarachnoid hemorrhage. CONCLUSIONS: In our cohort of saccular ICA aneurysms treated with Pipeline flow diversion that demonstrated persistent aneurysm filling at one year, there were no instances of delayed rupture during the study period. This data suggests that observation may be appropriate for continued aneurysm filling at least in the first several years following Pipeline placement.

Safety and efficacy of pipeline embolization device treatments for intradural internal carotid artery aneurysms in a single center in a Japanese population.

The pipeline embolization device (PED) is the most common flow diverter device in the world. To date, there have been no reports of treatment outcomes specific to intradural internal carotid artery (ICA) aneurysms. The safety and efficacy of the PED treatments for intradural ICA aneurysms are reported. 131 patients with 133 aneurysms underwent PED treatments for intradural ICA aneurysms. The mean aneurysm dome size and neck length were 12.7 ± 4.3 mm and 6.1 ± 2.2 mm, respectively. We used adjunctive endosaccular coil embolization for 88 aneurysms (66.2%). A total of 113 aneurysms (85%) were angiographically followed up 6 months following the procedure, and 93 aneurysms (69.9%) were followed up for 1 year. The angiographic outcome at 6 months showed that 94 (83.2%) aneurysms had O'Kelly-Marotta (OKM) grade D, 6 (5.3%) had C, 10 (8.8%) had B, and 3 (2.7%) had A. At 1 year, 82 (88.2%) aneurysms had OKM grade D, 6 (6.5%) had C, 3 (3.2%) had B, and 2 (2.2%) had A. Multivariate analysis showed that aneurysm neck size and adjunctive coiling were statistically significant in aneurysm occlusion status. Major morbidity modified Rankin Scale >2 and mortality rates related to procedures were 3.0% and 0%, respectively. Delayed aneurysm ruptures were not observed. These results reveal that PED treatment of intradural ICA aneurysms is safe and efficacious. The combined use of adjunctive coil embolization not only prevents delayed aneurysm ruptures but also contributes to an increase in the rate of complete occlusion.

Safety and efficacy of flow diverter stents in the treatment of middle cerebral artery aneurysms: a single-center experience and follow-up data

This study aims to evaluate the safety and efficacy of flow diverters (FDs) in the treatment of middle cerebral artery (MCA) aneurysms and share the follow-up (F/U) results. The treatment and F/U results of 76 MCA aneurysms treated with the flow re-direction endoluminal device (FRED), FRED Jr., and pipeline embolization device (PED) FD stents were evaluated retrospectively. The aneurysm occlusion rates were compared between FDs, and the integrated and jailed branches were evaluated through follow-ups. The oversizing of the stent was compared between occluded/non-occluded aneurysms and integrated branches. The mean F/U duration was 32 ± 6.3 months, and the mean aneurysm diameter was 4.45 mm. A total of 61 (80.3%) aneurysms were wide-necked; 73 (96.1%) were saccular; 52 (68.4%) were located at the M1 segment; and 36 (45.6%) FREDs, 23 (29.1%) FRED Jr.s, and 19 (24.1%) PEDs were used for treatment. The overall occlusion rates for the 6-, 12-, 24-, 36-, and 60-month digital subtraction angiographies were 43.8%, 63.5%, 73.3%, 85.7%, and 87.5% respectively. The last F/U occlusion rates were 67.6% for FRED, 66.7% for PED, and 60.6% for FRED Jr. (P = 0.863). An integrated branch was covered with an FD during the treatment of 63 (82.8%) aneurysms. A total of six (10%) of the integrated branches were occluded without any symptoms at the last F/U appointment. The median oversizing was 0.45 (0-1.30) for occluded aneurysms, and 0.50 (0-1.40) for non-occluded aneurysms (P = 0.323). The median oversizing was 0.70 (0.45-1.10) in occluded integrated branches and 0.50 (0-1.40) in non-occluded branches (P = 0.131). In-stent stenosis was seen in 22 (30.1%) of the stents at the 6-month F/U and in only 2 (4.7%) at the 24-month F/U. Thus, none of the patients had any neurological deficits because of the in-stent stenosis. Severe in-stent stenosis was seen in two stents. MCA aneurysms tend to be complex, with integrated branches and potentially wide necks. FD stents are safe and effective in the treatment of MCA aneurysms, and the patency of the side and jailed branches is preserved in most cases. Higher occlusion and lower in-stent stenosis rates are seen with longer F/U durations.

Abstract Number ‐ 140: Transcranial Doppler Emboli Monitoring for Stroke Prevention after Flow Diversion: A Single Center Experience

Introduction Following the favorable clinical and radiographical results of flow diversion, its use has continually expanded for the treatment of complex intracranial aneurysms. The high metal surface of flow diverters (FD) increases the risk of thromboembolic complications. Current emboli monitoring data after FD placement is limited. Transcranial doppler (TCD) offers a non‐invasive evaluation of microembolic signals and might be a valuable tool to prevent ischemic complications. We evaluated the rate of embolic signals and their management after FD implantation. Methods We performed a retrospective, single‐center evaluation of adult patients who underwent a FD procedure with the Pipeline Embolization Device (PED) for unruptured intracranial aneurysms between 2012 and 2016. Covariates included patient demographics, comorbidities, aneurysm characteristics, procedure characteristics, and post‐procedure TCD emboli monitoring (immediate and &gt;12 hours post‐operative). TCD emboli signals were classified as positive (&lt; 15 microembolic signals) and strongly positive (&gt;15 signals). The primary outcome was the rate of symptomatic stroke at 2 and 12 weeks in these patients. Results 105 patients with 132 aneurysms were analyzed. Mean age was 59.7 years, and 78% were females. Mean aneurysm size was 7.8 ± 6.4 mm. Most of them were located in the paraclinoid region (40%). Two PEDs were implanted in 12 (11%) cases and adjunctive coiling was performed in 15 (14%) cases. Microemboli were detected in 11.4% of cases (12/105 patients) after PED deployment. In 5/12 patients, the emboli resolved upon repeat testing with no intervention. In 6/12 patients, further heparinization, additional clopidogrel administration, or change in antiplatelet agents were needed. These treatments reduced the microembolic events. In 1 patient who was clopidogrel‐resistant and a ticagrelor super‐responder, mechanical thrombectomy was necessary due to acute in‐stent thrombosis. There were no symptomatic strokes at 2 and 12 weeks. Conclusions TCD emboli monitoring can be a powerful non‐invasive tool for the early identification and prevention of thromboembolic events after FD implantation. Early detection of microembolic signals offers the possibility to modify postoperative management, avoid silent emboli, and potentially avoid symptomatic strokes.

Pipeline embolization devices for the treatment of nonsaccular aneurysms in pediatric patients.

Pediatric nonsaccular aneurysms are rare but challenging lesions; pipeline embolization devices (PEDs) are their potential treatment option. In this study, we aimed to evaluate the safety and efficacy of PEDs for treatment of these aneurysms. We retrospectively selected pediatric patients with nonsaccular aneurysms treated using PEDs between June 2015 and July 2021 from our prospectively maintained database. For each patient, demographics, aneurysm characteristics, procedure details, and clinical and angiographic follow-up data were collected and summarized. This study included 16 pediatric patients with 16 nonsaccular aneurysms treated with PEDs. A median clinical follow-up time of 1,376 days was achieved in 93.75% of the patients. The complication rate of the included patients was 25%, with two patients developing mass effect, one patient undergoing major ischemic stroke, and one patient experiencing stent foreshortening after the procedure. The complete occlusion rate of aneurysms without any neurologic sequelae was 93.33%, with a median angiographic follow-up period of 246 days. The mortality rate was 6.25%. The use of PEDs to treat pediatric nonsaccular aneurysms is feasible, with a high rate of complete occlusion of the aneurysm and favorable follow-up outcomes.

Letter: Commentary: The Pennsylvania Postmarket Multicenter Experience With Flow Redirection Endoluminal Device.

To the Editor: We read with great interest the commentary by Restrepo et al1 discussing our Pennsylvania multicenter postmarket experience with the Flow Redirection Endoluminal Device (FRED) (MicroVention Inc).2 We thank the authors for their interest and the editor for the opportunity to respond. We agree with the authors regarding the multiple important points raised in their commentary. As stated, endoluminal flow diversion (FD) has revolutionized the treatment paradigm of intracranial aneurysms, eventually becoming the standard-of-care treatment for a wide range of lesions, starting from internal carotid artery aneurysms with continuous expansion of its “on-label” utility to multiple “off-label” indications including more distally located and nonsaccular morphologically complex aneurysms.3,4 Despite the initial paradigm-shifting results, improvement of the devices' safety, mostly in decreasing thromboembolic complications, which are the most feared complications of these devices continued to be underway.5,6 These refinements encompassed incessant technical modifications such as introducing new endoluminal devices, establishing intrasaccular flow divertors with the Woven EndoBridge (MicroVention Inc) being the prodigy of these devices,7,8 and surface modifications feature of the existing devices such as Pipeline Embolization Device (PED) (Medtronic) Shield and the FRED-X devices. While large multicenter experiences are currently lacking from the United States, it is worth noting that thromboembolic rates reported from 3 international multicenter studies using the PED Shield (6.4%,9 3.3%,10 2.5%11) were not different from earlier studies using prior PED versions (eg, Prospective Study on Embolization of Intracranial Aneurysms with the Pipeline Device 2.1%12 and IntrePED 3.3%13). Concurrently to the PED Shield, the FRED-X device features a similar nanopolymer surface modification aiming to reduce device thrombogenicity. However, clinical data remain pending to be seen whether there are significant differences in occlusion rates or device's safety profile compared with its predecessor. Multiple questions currently remain in the FD literature; these include the long-term efficacy of the different devices and whether there are any safety/efficacy differences between these devices. A recent systematic review reported a pooled 5-year complete occlusion rate of 96% with most of the literature studies using PED14; however, the analysis did not account for the different FD devices nor particular aneurysmal location, and further studies on this remain warranted. Moreover, limited data are currently known regarding which aneurysm type might be suited for each of those devices and head-to-head comparative performance data of the different devices in certain aneurysms location, for which prospective trials would be needed. Until then, it is likely that operators' technical preferences and personal experiences will continue to be the main impetus for device selection in aneurysms treatment. A recently published survey directed to the US neurointerventional community aimed to elicit common themes in their adoption of the newly introduced devices (ie, Surpass Evolve [Stryker Neurovascular] and FRED devices) to the US market. In this survey, PED was reported as the most common choice for giant aneurysms and ruptured cases (PED Shield in particular), whereas FRED Jr was commonly chosen for distal aneurysms with small parent vessel diameters and Surpass, the device of choice for aneurysms with large parent vessels.15 It has been argued before that the decrease in complications likely stemmed from the device's adequately implied learning curve over time as well as attention to dual antiplatelet therapy and platelet function testing,16 particularly in light of recent level I randomized evidence supporting regular platelet function testing and subsequent medications adjusting in clopidogrel nonresponders or hyporesponders.6 Nonetheless and concurrently to the continuous expansion of the neurointerventional armamentarium with new devices and technologies, a more nuanced approach will likely be needed to identify the most appropriate device with a patient-centered case-specific–based approach.

Long-term outcomes and dynamic changes of in-stent stenosis after Pipeline embolization device treatment of intracranial aneurysms

BackgroundFlow diverters have revolutionized the treatment of intracranial aneurysms. However, the delayed complications associated with flow diverter use are unknown.ObjectiveTo evaluate the incidence, severity, clinical outcomes, risk factors, and dynamic...

Effects of different stent size selection on pipeline embolization device treatment of intracranial aneurysms.

Pipeline embolization device (PED) is becoming increasingly common in therapeutic practice. In idealized model studies, treatment effectiveness may vary with different stent sizes in the same vasculature. The true effect of stent size selection in the clinical setting remains unknown, however. To determine the true effect of stent size selection in the clinical setting. It is a retrospective review. A retrospective review was conducted on consecutive patients with aneurysms treated with a PED at our institution. The primary exposures were the difference between the diameter of the stent and the parent artery (DD) and the difference between the length of the stent and the aneurysm neck (DL). The outcomes were the clinical and angiographic results, perioperative complications, balloon application, and in-stent stenosis. The results were generated using univariable and multivariable logistic regression and restricted cubic spline (RCS) curves. A larger DD was significantly associated with incomplete occlusion [odds ratio (OR) = 2.37; 95% confidence interval (CI) = 1.43-3.98; p < 0.001], while a larger DL was significantly associated with balloon application (OR = 1.12; 95% CI = 1.02-1.23; p = 0.021) and in-stent stenosis (>25%) (OR = 1.07; 95% CI = 1.01-1.16; p = 0.042). The RCS curve indicated that the risk of incomplete occlusion increased as the DD became larger, the possibility of balloon application increased as the DL increased when the DL was >5.7 mm, and the risk of in-stent stenosis (>25%) increased as the DL increased. In the clinical setting, stent selection was associated with treatment effectiveness and may add to the treatment burden. These occurrences should be considered for aneurysms treated with PED.

Flow diversion for posterior circulation aneurysms: a multicenter retrospective study.

The prevalence of intracranial aneurysms is approximately 3% worldwide. Posterior circulation (PC) aneurysms have a higher risk of treatment complications than anterior circulation aneurysms. Improving the survival rate and quality of life of patients with PC aneurysms remains one of the most important issues in the field. Flow diverter (FD) treatment of PC aneurysms remains controversial. We aimed to investigate the effects of FD treatment and analyze differences among different application methods or aneurysm types in PC aneurysms. This is a multicenter retrospective study. Patients with PC aneurysms treated with the pipeline embolization device (PED) or Tubridge embolization device (TED) between 2015 and 2020 in five neurovascular centers were retrospectively enrolled. The primary outcomes were major perioperative complication, clinical outcome, and aneurysm occlusion rates. Univariable and multivariable logistic regression analyses were used to determine the risk factors of each outcome. In total, 252 aneurysms were included. Major perioperative complication, favorable clinical outcome, and complete occlusion rates were 7.5%, 91.0%, and 79.1%, respectively. Compared with other types of aneurysms, dissecting aneurysms had the best clinical outcome and highest occlusion rate. Both clinical and angiographic outcomes were independently associated with the aneurysm location at the basilar artery. Aneurysm size was not associated with any outcome. TED had similar clinical and angiographic outcomes compared with PED but more perioperative major complications. Tandem treatment and coiling assistance may have poorer clinical outcomes but similar occlusion rates. Single- and multiple-stent treatments had similar outcomes. FD treatment of PC aneurysms achieved favorable clinical outcomes and long-term aneurysm occlusion rates with acceptable perioperative complication rates, especially in dissecting and non-basilar artery aneurysms. There was no additional improvement in outcomes with coiling assistance, multi-stent application, or tandem treatment. Therefore, the use of PC aneurysms should be carefully considered.