Stent-to-vessel diameter ratio is associated with in-stent stenosis after flow-diversion treatment of intracranial aneurysms

BACKGROUND AND PURPOSE

Flow-diversion treatment for intracranial aneurysms has been associated with the development of in-stent stenosis (ISS) for unclear reasons. We assess whether the size of the stent relative to that of the vessel (the stent-to-vessel diameter ratio, or SVR) may be predictive of the development of ISS after treatment with flow diverters.

METHODS

We retrospectively reviewed patients with unruptured intracranial aneurysms who underwent flow-diversion treatment using either the Pipeline or Tubridge embolization device from September 2018 to September 2022. The relationship between SVR and ISS was analyzed. Multiple logistic regression models were used to determine the significant predictors.

RESULTS

A total of 458 patients with 481 aneurysms were included. In a mean angiographic follow-up of 10.73 ± 3.97 months, ISS was detected in 68 cases (14.1 %). After adjusting for candidate variables, a higher distal SVR (DSVR) was associated with an increased risk of ISS (adjusted odds ratio [aOR] = 3.420, 95 % confidence interval [CI] = 1.182 - 9.889, p = 0.023). We conducted a subgroup analysis of the two different flow diverters to assess the effects of their individual characteristics. Our results showed a significant association between the DSVR and the incidence of ISS in both the Pipeline (aOR = 4.033, 95 % CI = 1.156-14.072, p = 0.029) and Tubridge groups (aOR = 11.981, 95 % CI=1.005-142.774, p = 0.049).

CONCLUSION

A higher DSVR was associated with an increased risk of ISS. This may help neurointerventionalists select an appropriate stent size when conducting flow-diversion treatment for intracranial aneurysms.

Predicting postinterventional rupture of intracranial aneurysms using arteriography-derived radiomic features after pipeline embolization

Background and purpose

Postinterventional rupture of intracranial aneurysms (IAs) remains a severe complication after flow diverter treatment. However, potential hemodynamic mechanisms underlying independent predictors for postinterventional rupture of IAs remain unclear. In this study, we employed arteriography-derived radiomic features to predict this complication.

Methods

We included 64 patients who underwent pipeline flow diversion for intracranial aneurysms, distinguishing between 16 patients who experienced postinterventional rupture and 48 who did not. We performed propensity score matching based on clinical and morphological factors to match these patients with 48 patients with postinterventional unruptured IAs at a 1:3 ratio. Postinterventional digital subtraction angiography were used to create five arteriography-derived perfusion parameter maps and then radiomics features were obtained from each map. Informative features were selected through the least absolute shrinkage and selection operator method with five-fold cross-validation. Subsequently, radiomics scores were formulated to predict the occurrence of postinterventional IA ruptures. Prediction performance was evaluated with the training and test datasets using area under the curve (AUC) and confusion matrix-derived metrics.

Results

Overall, 1,459 radiomics features were obtained, and six were selected. The resulting radiomics scores had high efficacy in distinguishing the postinterventional rupture group. The AUC and Youden index were 0.912 (95% confidence interval: 0.767-1.000) and 0.847 for the training dataset, respectively, and 0.938 (95% confidence interval, 0.806-1.000) and 0.800 for the testing dataset, respectively.

Conclusion

Radiomics scores generated using arteriography-derived radiomic features effectively predicted postinterventional IA ruptures and may aid in differentiating IAs at high risk of postinterventional rupture.

Pipeline Embolization Device for intracranial aneurysms presenting with mass effect: a large Chinese cohort

BACKGROUND

Unruptured intracranial aneurysm treatment aims to reduce the risk of aneurysm rupture and bleeding, relieves symptoms and improve the quality of life for patients. This study aimed to assess the safety and efficacy of Pipeline Embolization Device (PED, Covidien/Medtronic, Irvine, CA) treatment for intracranial aneurysms presenting with mass effect in real-world settings.

METHODS

We selected patients from the PED in China Post-Market Multi-Center Registry Study with mass effect presentation. The study endpoints included postoperative mass effect deterioration and mass effect relief at follow-up (3-36 months). We conducted multivariate analysis to identify factors associated with mass effect relief. Subgroup analyses by aneurysm location, size and form were also performed.

RESULTS

This study included 218 patients with a mean age of 54.3±11.8 years and a female predominance of 74.0% (162/218). The postoperative mass effect deterioration rate was 9.6% (21/218). During a median follow-up period of 8.4 months, the mass effect relief rate was 71.6% (156/218). Notably, immediate aneurysm occlusion following treatment was significantly associated with mass effect relief (OR 0.392, 95% CI, 0.170 to 0.907, p=0.029). Subgroup analysis demonstrated that adjunctive coiling contributed to mass effect relief in cavernous aneurysms, while dense embolism impeded symptom relief in aneurysms<10 mm and saccular aneurysms.

CONCLUSIONS

Our data confirmed the efficacy of PED in relieving mass effect. The findings of this study provide support for endovascular treatment to alleviate mass effect in unruptured intracranial aneurysms.

TRIAL REGISTRATION NUMBER

NCT03831672.

Predictors of In-Stent Stenosis Following the Implantation of Pipeline Embolization Devices for the Treatment of Aneurysms Located at or beyond the Circle of Willis in the Anterior Circulation

BACKGROUND AND PURPOSE

In-stent stenosis is commonly observed after stent implantation. There is no consensus on the contributing factors for in-stent stenosis, especially for aneurysms located at or beyond the circle of Willis in the anterior circulation. This study aimed to investigate the morbidity and determinants of in-stent stenosis in distal anterior circulation aneurysms following the implantation of Pipeline Embolization Devices.

MATERIALS AND METHODS

Patients who underwent Pipeline Embolization Device treatment at our center between January 1, 2018, and June 15, 2023, were enrolled. Distal anterior circulation aneurysms were defined as those occurring at or beyond the circle of Willis, including anterior communicating artery aneurysms, anterior cerebral artery aneurysms, and MCA aneurysms. Baseline information, aneurysm characteristics, and follow-up data of patients were analyzed. Patients were divided into 2 groups: the in-stent stenosis group (patients with a loss of >25% of the lumen diameter of the parent artery) and the non-in-stent stenosis group. Binary logistic regression and restricted cubic spline curves were used to explore risk factors.

RESULTS

We included 85 cases of 1213 patients treated with flow-diverter devices at our hospital. During an average follow-up period of 9.07 months, the complete occlusion rate was 77.64%. The overall incidence of in-stent stenosis was 36.47% (31/85), of which moderate stenosis accounted for 9.41% (8/85), and severe stenosis, 5.88% (5/85) (triglyceride-glucose index ≥ 8.95; OR = 6.883, P = .006). The difference in diameters between the stent and parent artery of ≥0.09 mm (OR = 6.534, P = .015) and 55 years of age or older (OR = 3.507, P = .036) were risk factors for in-stent stenosis. The restricted cubic spline curves indicated that the risk of in-stent stenosis increased as the difference in diameter between stent and parent artery and the triglyceride-glucose index increased.

CONCLUSIONS

Compared with the on-label use of Pipeline Embolization Devices, the rate of in-stent stenosis did not obviously increase when treating distal anterior circulation aneurysms with these devices. The incidence of in-stent stenosis was 36.47% when defined as a lumen diameter loss of >25%, and 15.2% when defined as a lumen diameter loss of >50%. Stent-size selection and biochemical indicators can potentially impact the incidence of in-stent stenosis.

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

BACKGROUND

Flow diverters have revolutionized the treatment of intracranial aneurysms. However, the delayed complications associated with flow diverter use are unknown.

OBJECTIVE

To evaluate the incidence, severity, clinical outcomes, risk factors, and dynamic changes associated with in-stent stenosis (ISS) after treatment with a Pipeline embolization device (PED).

METHODS

Patients who underwent PED treatment between 2015 and 2020 were enrolled. The angiographic, clinical, and follow-up data of 459 patients were independently reviewed by four neuroradiologists to identify ISS. Binary logistic regression was conducted to determine ISS risk factors, and an ISS-time curve was established to demonstrate dynamic changes in ISS after PED implantation.

RESULTS

Of the 459 treated patients, 69 (15.0%) developed ISS. At follow-up, nine patients (2.0%) with ISS demonstrated reversal, while 18 (3.9%) developed parental artery occlusion. A total of 380 patients (82.8%) achieved complete aneurysm occlusion (O'Kelly-Marotta grade D). Patients with posterior-circulation aneurysm (OR=2.895, 95% CI (1.732 to 4.838; P<0.001) or balloon angioplasty (OR=1.992, 95% CI 1.162 to 3.414; P=0.037) were more likely to develop ISS. Patients aged >54 years (OR=0.464, 95% CI 0.274 to 0.785; P=0.006) or with a body mass index of >28 kg/m2 (OR=0.427, 95% CI 0.184 to 0.991; P=0.026) had a lower ISS risk. Intimal hyperplasia initiated by PED placement peaked within 1 year after the procedure, rarely progressed after 12 months, and tended to reverse within 24 months.

CONCLUSIONS

ISS is a common, benign, and self-limiting complication of PED implantation in the Chinese population.

Parent artery occlusion after pipeline embolization device implantation of intracranial saccular and fusiform aneurysms

BACKGROUND

Studies reporting parent artery occlusion (PAO) after pipeline embolization device (PED) implantation are limited. The aim of this study was to investigate the incidence rate and risk factors of PAO after PED implantation.

METHODS

In this retrospective study, we enrolled consecutive patients with intracranial saccular and fusiform aneurysms treated with PED implantation at our institution. Multivariate logistic regression analysis was subsequently performed to determine the risk factors for PAO.

RESULTS

A total of 588 saccular and fusiform aneurysms were finally enrolled in the study. PAO was found in 14 (2.38%) aneurysms. The aneurysm complete occlusion rate was 79.6%. Compared with the non-PAO group, aneurysms in the PAO group were larger in size (20.08 vs 9.61 mm; p<0.001), had a greater neck diameter (9.92 vs 6.15 mm; p=0.001), and had higher frequencies of adjunctive coils (64.3% vs 35.7%; p=0.028). In the multivariate logistic analysis, aneurysm size (OR 1.12, 95% CI 1.02 to 1.24; p=0.016) and the presence of poor wall apposition after balloon angioplasty (OR 7.74, 95% CI 1.28 to 46.82; p=0.026) were associated with PAO occurrence after adjusting for confounding factors.

CONCLUSIONS

In this study, the incidence rate of PAO following PED implantation was 2.38% in intracranial saccular and fusiform aneurysms. Aneurysm size and residual presence of poor wall apposition after balloon angioplasty were risk factors for PAO. Further research is required to better understand the mechanisms of PAO.

No Delayed Ruptures on Long-Term Follow-Up of a Case Series of Persistently Filling Saccular Internal Carotid Artery Aneurysms After Flow Diversion With the Pipeline Embolization Device

BACKGROUND AND OBJECTIVES

Flow diversion of intracranial aneurysms results in high occlusion rates. However, 10% to 20% remain persistently filling at 1 year. Often, these are retreated, but benefits of retreatment are not well established. A better understanding of the long-term rupture risk of persistently filling aneurysms after flow diversion is needed.

METHODS

Our institutional database of 974 flow diversion cases was queried for persistently filling saccular aneurysms of the clinoidal, ophthalmic, and communicating segments of the internal carotid artery treated with the pipeline embolization device (PED, Medtronic). Persistent filling was defined as continued flow into the aneurysm on 1 year catheter angiogram. The clinical record was queried for retreatments and delayed ruptures. Clinical follow-up was required for at least 2 years.

RESULTS

Ninety-four persistent aneurysms were identified. The average untreated aneurysm size was 5.6 mm. A branch vessel originated separately 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 >95% filling at 1 year, and 61% were filling 5% to 95% of their original size. The mean follow-up time was 4.9 years, including 41 cases with >5 years. No retreatment was undertaken in 91.5% of aneurysms. There were no cases of delayed subarachnoid hemorrhage.

CONCLUSION

Among saccular internal carotid artery aneurysms treated with PED that demonstrated persistent aneurysm filling at 1 year, there were no instances of delayed rupture on long-term follow-up. These data suggest that observation may be appropriate for continued aneurysm filling at least in the first several years after PED placement.

Predictors of aneurysmal occlusion following intracranial aneurysms treatment with pipeline embolization device

PURPOSE

Pipeline embolization device (PED) is thought to induce aneurysmal occlusion through diversion of flow away from the aneurysmal sac with subsequent thrombosis and endothelialization. The impact of different factors especially hypertension (HTN)-a known predisposing factor to hypercoagulability and altered endothelial function-on aneurysmal occlusion after flow diversion has not been studied. We sought to determine predictors of aneurysmal occlusion following PED treatment focusing on impact of blood pressure.

METHODS

Database of patients with cerebral aneurysms treated with PED from 2013 to 2019 at our institution was retrospectively reviewed. Patients were defined as hypertensive if (1) they had a documented history of HTN requiring anti-HTN medications or (2) average systolic blood pressure on three measurements was > 130 mmHg. The primary outcome was aneurysm occlusion status at the last imaging follow-up. Multivariable logistic regression model was constructed to assess the effect of HTN on occlusion, controlling for age, smoking, aneurysmal size, fusiform morphology, posterior circulation location, and incorporated branches.

RESULTS

A total of 331 aneurysms in 294 patients were identified for this analysis. The mean age was 59 years (79.9% female). Fifty-five percent of the cohort were classified as hypertensive. When controlling for other potential confounders, hypertensive patients trended toward higher odds of achieving complete occlusion compared to non-hypertensive patients (OR = 2.05; 95% CI = 0.99-4.25; p = 0.052). Meanwhile, age (OR = 0.91; 95% CI = 0.88-0.95; p < 0.001) and an incorporated branch into an aneurysm (OR = 0.22; 95% CI = 0.08-0.58; p < 0.002) were associated with decreased odds for complete aneurysmal occlusion.

CONCLUSION

Hypertensive patients show a trend toward higher odds of achieving complete occlusion when controlling for potential confounders. The HTN-induced hypercoagulable state, enhanced endothelial activation, and altered extracellular matrix regulation might be the contributing factors. Further research is warranted to explore clinical implications of these findings.

The Impact of Dual Antiplatelet Therapy Duration on Unruptured Aneurysm Occlusion After Flow Diversion: A Multicenter Study

OBJECTIVE

Endoluminal flow diversion reduces blood flow into intracranial aneurysms, promoting thrombosis. Postprocedural dual antiplatelet therapy (DAPT) is necessary for the prevention of thromboembolic complications. The purpose of this study is to therefore assess the impact that the type and duration of DAPT has on aneurysm occlusion rates and iatrogenic complications after flow diversion.

METHODS

A retrospective review of a multicenter aneurysm database was performed from 2012 to 2020 to identify unruptured intracranial aneurysms treated with single device flow diversion and ≥12-month follow-up. Clinical and radiologic data were analyzed with aneurysm occlusion as a function of DAPT duration serving as a primary outcome measure.

RESULTS

Two hundred five patients underwent flow diversion with a single pipeline embolization device with 12.7% of treated aneurysms remaining nonoccluded during the study period. There were no significant differences in aneurysm morphology or type of DAPT used between occluded and nonoccluded groups. Nonoccluded aneurysms received a longer mean duration of DAPT (9.4 vs 7.1 months, P = 0.016) with a significant effect of DAPT duration on the observed aneurysm occlusion rate (F(2, 202) = 4.2, P = 0.016). There was no significant difference in the rate of complications, including delayed ischemic strokes, observed between patients receiving short (≤6 months) and prolonged duration (>6 months) DAPT (7.9% vs 9.3%, P = 0.76).

CONCLUSIONS

After flow diversion, an abbreviated duration of DAPT lasting 6 months may be most appropriate before transitioning to low-dose aspirin monotherapy to promote timely aneurysm occlusion while minimizing thromboembolic complications.

Pipeline versus Tubridge in the treatment of unruptured posterior circulation aneurysms

BACKGROUND

To compare the safety and efficacy of pipeline embolization device (PED) and Tubridge flow diverter (TFD) for unruptured posterior circulation aneurysms.

METHODS

Posterior aneurysm patients treated with PED or TFD between January, 2019, and December, 2021, were retrospectively reviewed. Patients' demographics, aneurysm characteristics, treatment details, complications, and follow-up information were collected. The procedural-related complications and angiographic and clinical outcome were compared.

RESULTS

A total of 107 patients were involved; PED was applied for 55 patients and TFD for 52 patients. A total of 9 (8.4%) procedural-related complications occurred, including 4 (7.3%) in PED group and 5 (9.6%) in TFD group. During a mean of 10.3-month angiographic follow-up for 81 patients, complete occlusion was achieved in 35 (85.4%) patients in PED group and 30 (75.0%) in TFD group. The occlusion rate of PED group is slightly higher than that of TFD group. A mean of 25.0-month clinical follow-up for 107 patients showed that favorable clinical outcome was achieved in 53 (96.4%) patients in PED group and 50 (96.2%) patients in TFD group, respectively. No statistical difference was found in terms of procedural-related complications (p = 0.737), occlusion rate (p = 0.241), and favorable clinical outcome (0.954) between groups.

CONCLUSIONS

The current study found no difference in complication, occlusion, and clinical outcome between PED and TFD for unruptured PCAs.

Learning curve in pipeline embolization device: results from the pipeline embolization device in China post-market multicentre registry study

BACKGROUND

Intracranial aneurysms pose a significant health issue, affecting 3-5% of the adult population. The pipeline embolization device (PED) has emerged as a promising treatment for these lesions. This study aimed to investigate the impact of operator experience on complication and poor outcome rates, as well as the learning curve for PED.

METHODS

A total of 217 patients were consecutively enroled from four eligible centres and divided into three groups based on the number of procedures performed: group 1 (first 10 procedures), group 2 (11-20 procedures), and group 3(>20 procedures). Major complications include operation-related ischaemic or haemorrhagic events and mass effect deterioration. Poor outcome was defined as a modified Rankin Scale score greater than 2 at discharge. Cumulative summation (CUSUM) analysis was generated to assess the learning curve according to major complications and poor outcome.

RESULTS

The study found that major complications and poor outcomes occurred in 5.1% and 2.3% of cases, respectively. The rate of major complications decreased from 10.0% in group 1 to 2.9% in group 3 ( P =0.053), while the rate of poor outcomes decreased from 7.5% in group 1 to 0.7% in group 3 ( P =0.015). Multivariable regression analysis adjusted for covariates showed that operator experience was associated with a lower rate of poor outcomes ( P =0.034). CUSUM analysis demonstrated that the learning curve for avoiding major complications and poor outcomes required 27 (mean=13) and 40 (mean=20) cases, respectively.

CONCLUSIONS

These findings suggest that PED treatment requires a learning curve of 40 cases to achieve reproducibility regarding complications and functional results. Additionally, major complications and poor outcomes significantly decreases after the first 20 procedures. CUSUM analysis can serve as a useful tool for monitoring and assessing surgical performance.

Treatment of cerebral aneurysms with flow diversion or stent assisted coiling in patients on concurrent oral anticoagulation

BACKGROUND

Flow diversion and stent assisted coiling are increasingly utilized strategies in the endovascular treatment of cerebral aneurysms. Ischemic and hemorrhagic complications play an important role in the outcome following such embolizations. Little is published regarding patients on concurrent oral anticoagulation and undergoing such embolizations and the rates of complications and patient outcomes.

MATERIALS AND METHODS

Retrospective data for consecutive patients on concurrent oral anticoagulation undergoing flow diversion or stent assisted coiling for cerebral aneurysms was accessed from databases at the participating sites. Patient demographics, comorbidities, antiplatelet regimens, aneurysm characteristics, complications, and radiographic results were recorded and descriptive statistics reported.

RESULTS

Eleven patients were identified undergoing embolization in the setting of preoperative anticoagulant use and included seven patients undergoing flow diversion and four patients undergoing stent assisted coiling. There was a wide range of antiplatelet and anticoagulant management strategies. There were four major complications in three patients (27.2%) to include two serious bleeding events in addition to ischemic strokes. Both serious bleeding events occurred in patients continued on oral anticoagulation with the addition of antiplatelets. At a mean follow-up of 9.6 months, three aneurysms had continued filling for a good radiographic outcome of 72.7%.

CONCLUSIONS

Anticoagulant and antiplatelet use in the setting of flow diversion or stent assisted coiling may carry increased risks as compared to historical norms and, for flow diversion, offer decreased efficacy.

Microsurgical Treatment of Previously Coiled Giant Aneurysms: Experience with 6 Cases and Literature Review

OBJECTIVE

Surgical treatment of insufficiently embolized (coiled) or recurrent giant aneurysms has not been well established in the literature. The aim of this study is to bring up the surgical difficulties of these rare aneurysms and to offer solutions.

METHODS

A database was queried for giant aneurysms that had been previously embolized and subsequently required surgical treatment. We only found 29 aneurysms in the literature and here, we report 6 more surgical cases with patient characteristics, radiological studies, applied surgical techniques, and outcomes which were reviewed retrospectively.

RESULTS

Four females and 2 males, with a mean age of 45.6 years took part in the study. The most common aneurysm location was the middle cerebral artery. While 5 aneurysms were successfully clipped, 1 was excised and the neck was closed with micro sutures. The coils were compulsorily removed in 3 patients. Postoperative digital subtraction angiography confirmed total occlusion of the aneurysms in all cases. Overall morbidity was 16.6%. There was no mortality. No recurrence was observed in the angiographic follow-up (mean 22.6 months, range 7-47 months). The literature review also determined that 97.1% of 35 previously coiled giant aneurysms (including ours) were occluded using various surgical techniques, with 82.8% good outcome.

CONCLUSIONS

Surgical clipping is a safe and effective procedure for the treatment of insufficiently embolized or recurrent giant aneurysms after coiling. If possible, the coils should not be removed. However, if safe clipping is not possible due to the coils, the removal of the coils should not be avoided.

Methylprednisolone is related to lower incidence of postoperative bleeding after flow diverter treatment for unruptured intracranial aneurysm

Background and objectives

Regarding the anti-inflammatory effect, methylprednisolone is a candidate to prevent patients with unruptured intracranial aneurysms (UIAs) from postoperative bleeding (PB) after flow diverter (FD) treatment. This study aimed to investigate whether methylprednisolone is related to a lower incidence of PB after FD treatment for UIAs.

Methods

This study retrospectively reviewed UIA patients receiving FD treatment between October 2015 and July 2021. All patients were observed until 72  h after FD treatment. The patients receiving methylprednisolone (80  mg, bid, for at least 24 h) were considered as standard methylprednisolone treatment (SMT) users, otherwise as non-SMT users. The primary endpoint indicated the occurrence of PB, including subarachnoid hemorrhage, intracerebral hemorrhage, and ventricular bleeding, within 72 h after FD treatment. This study compared the incidence of PB between SMT users and non-SMT users and investigated the protective effect of SMT on PB after FD treatment using the Cox regression model. Finally, after controlling the potential factors related to PB, we performed subgroup analysis to further confirm the protective effect of SMT on PB.

Results

This study finally included 262 UIA patients receiving FD treatment. PB occurred in 11 patients (4.2%), and 116 patients (44.3%) received SMT postoperatively. The median time from the end of surgery to PB was 12.3 h (range: 0.5-48.0 h). SMT users had a lower incidence of PB comparing with non-SMT users (1/116, 0.9% vs. 10/146, 6.8%, respectively; p = 0.017). The multivariate Cox analysis demonstrated that SMT users (HR, 0.12 [95%CI, 0.02-0.94], p = 0.044) had a lower risk of PB postoperatively. After controlling the potential factors related to PB (i.e., gender, irregular shape, surgical methods [FD and FD + coil] and UIA sizes), the patients receiving SMT still had a lower cumulative incidence of PB, comparing with patients receiving non-SMT (all p < 0.05).

Conclusion

SMT was correlated with the lower incidence of PB for patients receiving FD treatment and may be a potential method to prevent PB after the FD treatment.

In-Stent Stenosis After Pipeline Embolization Device in Intracranial Aneurysms: Incidence, Predictors, and Clinical Outcomes

BACKGROUND

In-stent stenosis (ISS) is a delayed complication that can occur after pipeline embolization device use when treating intracranial aneurysms (IAs).

OBJECTIVE

To assess the incidence, predictors, and outcomes of ISS.

METHODS

This was a retrospective, multicenter, observational study. All patient data were collected from a PLUS registry study. We collected data from patients with IA who completed digital subtraction angiography at follow-up and divided patients into "non-ISS," "mild ISS," or "severe ISS" groups. Multivariate logistic regression analysis was conducted to determine predictors of ISS.

RESULTS

A total of 1171 consecutive patients with 1322 IAs participated in this study. Angiographic follow-up was available for 662 patients with 728 IAs, and the mean follow-up time was 9 months. ISS was detected in 73 cases (10.03%), including 61 mild ISS cases and 12 severe ISS cases. Univariate and multivariable analysis demonstrated that current smoking history (mild ISS: OR 2.15, 95% CI 1.122-4.118, P = .021; severe ISS: OR 5.858, 95% CI 1.186-28.93, P = .030) and cerebral atherosclerosis (mild ISS: OR 5.694, 95% CI 3.193-10.15, P = .001; severe ISS: OR 6.103, 95% CI 1.384-26.91, P = .017) were independent predictors of ISS. Compared with the other groups, the severe ISS group had higher rate of ischemic stroke (33.3%).

CONCLUSION

ISS occurs in approximately 10.03% of cases at a mean follow-up of 9 months. Statistically, current smoking history and cerebral atherosclerosis are the main predictors of ISS. Severe ISS may be associated with higher risk of neurological ischemic events in patients with IA after pipeline embolization device implantation.

Development of the SAFETEA Scores for Predicting Risks of Complications of Preventive Endovascular or Microneurosurgical Intracranial Aneurysm Occlusion

BACKGROUND AND OBJECTIVES

Preventive unruptured intracranial aneurysm (UIA) occlusion can reduce the risk of subarachnoid hemorrhage, but both endovascular and microneurosurgical treatment carry a risk of serious complications. To improve individualized management decisions, we developed risk scores for complications of endovascular and microneurosurgical treatment based on easily retrievable patient, aneurysm, and treatment characteristics.

METHODS

For this multicenter cohort study, we combined individual patient data from patients with UIA aged 18 years or older undergoing preventive endovascular treatment (standard, balloon-assisted or stent-assisted coiling, Woven EndoBridge-device, or flow-diverting stent) or microneurosurgical clipping at one of the 10 participating centers from 3 continents between 2000 and 2018. The primary outcome was death from any cause or clinical deterioration from neurologic complications ≤30 days. We selected predictors based on previous knowledge about relevant risk factors and predictor performance and studied the association between predictors and complications with logistic regression. We assessed model performance with calibration plots and concordance (c) statistics.

RESULTS

Of the 1,282 included patients, 94 (7.3%) had neurologic symptoms that resolved <30 days, 140 (10.9%) had persisting neurologic symptoms, and 6 died (0.5%). At 30 days, 52 patients (4.1%) were dead or dependent. Predictors of procedural complications were size of aneurysm, aneurysm location, familial subarachnoid hemorrhage, earlier atherosclerotic disease, treatment volume, endovascular modality (for endovascular treatment) or extra aneurysm configuration factors (for microneurosurgical treatment, branching artery from aneurysm neck or unfavorable dome-to-neck ratio), and age (acronym: SAFETEA). For endovascular treatment (n = 752), the c-statistic was 0.72 (95% CI 0.67-0.77) and the absolute complication risk ranged from 3.2% (95% CI 1.6%-14.9%; ≤1 point) to 33.1% (95% CI 25.4%-41.5%; ≥6 points). For microneurosurgical treatment (n = 530), the c-statistic was 0.72 (95% CI 0.67-0.77) and the complication risk ranged from 4.9% (95% CI 1.5%-14.9%; ≤1 point) to 49.9% (95% CI 39.4%-60.6%; ≥6 points).

DISCUSSION

The SAFETEA risk scores for endovascular and microneurosurgical treatment are based on 7 easily retrievable risk factors to predict the absolute risk of procedural complications in patients with UIAs. The scores need external validation before the predicted risks can be properly used to support decision-making in clinical practice.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that SAFETEA scores predict the risk of procedural complications after endovascular and microneurosurgical treatment of unruptured intracranial aneurysms.

Machine learning to predict in-stent stenosis after Pipeline embolization device placement

Background

The Pipeline embolization device (PED) is a flow diverter used to treat intracranial aneurysms. In-stent stenosis (ISS) is a common complication of PED placement that can affect long-term outcome. This study aimed to establish a feasible, effective, and reliable model to predict ISS using machine learning methodology.

Methods

We retrospectively examined clinical, laboratory, and imaging data obtained from 435 patients with intracranial aneurysms who underwent PED placement in our center. Aneurysm morphological measurements were manually measured on pre- and posttreatment imaging studies by three experienced neurointerventionalists. ISS was defined as stenosis rate >50% within the PED. We compared the performance of five machine learning algorithms (elastic net (ENT), support vector machine, Xgboost, Gaussian Naïve Bayes, and random forest) in predicting ISS. Shapley additive explanation was applied to provide an explanation for the predictions.

Results

A total of 69 ISS cases (15.2%) were identified. Six predictors of ISS (age, obesity, balloon angioplasty, internal carotid artery location, neck ratio, and coefficient of variation of red cell volume distribution width) were identified. The ENT model had the best predictive performance with a mean area under the receiver operating characteristic curve of 0.709 (95% confidence interval [CI], 0.697–0.721), mean sensitivity of 77.9% (95% CI, 75.1–80.6%), and mean specificity of 63.4% (95% CI, 60.8–65.9%) in Monte Carlo cross-validation. Shapley additive explanation analysis showed that internal carotid artery location was the most important predictor of ISS.

Conclusion

Our machine learning model can predict ISS after PED placement for treatment of intracranial aneurysms and has the potential to improve patient outcomes.

The Pennsylvania Postmarket Multicenter Experience With Flow Redirection Endoluminal Device

BACKGROUND

The flow redirection endoluminal device (FRED) is a novel self-expanding double-layer nitinol braided flow diverter that recently received FDA approval. However, early postmarket studies from the United States are lacking.

OBJECTIVE

To report our short-term multicenter experience.

METHODS

Series of consecutive patients undergoing FRED treatment for intracranial aneurysms were queried from prospectively maintained registries at 4 North-American Centers in Pennsylvania (February 2020-June 2021). The pertinent baseline demographics, aneurysmal characteristics, and procedural outcomes were collected and analyzed, with primary outcome of aneurysmal occlusion and secondary outcome of safety and complications.

RESULTS

Sixty-one patients (median age 58 years, 82% female) underwent 65 FRED treatment procedures for 72 aneurysms. Most (86.1%) of the aneurysms were unruptured; 80.5% were saccular in morphology, and 87.5% were located along the internal carotid artery, with a median size of 7.1 mm (IQR 5.2-11.9 mm). Radiographic follow-up was available in 86.1% of the aneurysms, showing complete occlusion in 74.2% (80% in catheter angiography-only group), and near-complete occlusion in 11.3% of the cases (median 6.3 months), with 2.8% re-treated. Permanent ischemic complications were encountered in 2.8% of the cases, with no procedural mortality. A modified Rankin Scale of 0 to 2 was documented in 98.1% of the patients at the last clinical follow-up (median 6.1 months).

CONCLUSION

The results of the early postmarket experience with the FRED device show reasonable safety and adequate aneurysmal occlusion rates comparable with other flow diverters. However, more extensive multicenter studies with more extended follow-up data are needed to assess the long-term safety and durability of the device.

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

BACKGROUND AND PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Pipeline Embolization Device for the Treatment of Ruptured Intracerebral Aneurysms: A Multicenter Retrospective Study

Background and Purpose: The utilization of flow diversion for ruptured intracerebral aneurysms (IAs) is still limited. We aimed to demonstrate our multicenter experience using the pipeline embolization device (PED) for ruptured IAs that were difficult to treat by clipping and coiling.

Methods: Thirty-eight patients with ruptured IAs who underwent PED treatment from 2015 to 2020 were retrospectively reviewed. Factors associated with procedure-related stroke (ischemic and hemorrhagic) and clinical and angiography outcomes were analyzed.

Results: There were 14 (36.8%) saccular IAs, 12 (31.6%) blister-like IAs, and 12 (31.6%) dissecting IAs. Perforator involvement was noted in 10 (26.3%) IAs. Early PED placement ( ≤ 15 days) and adjunctive coiling treatment were performed in 27 (71.1%) and 22 (57.9%) cases, respectively. The overall rate of stroke-related complications was 31.6% (12/38) (including rates of 10.5% for procedure-related hemorrhagic complications and 15.8% for procedure-related infarction). The mortality rate was 13.2% (5/38), and 84.2% of patients (32/38) had favorable outcomes. Thirty-two (84.2%) patients underwent follow-up angiographic evaluations; of these, 84.4% (27 patients) had complete occlusion and 15.6% had incomplete obliteration. Multivariate analysis revealed that early PED placement was not associated with a high risk of procedure-related stroke or an unfavorable outcome. Adjunctive coiling exhibited an association with procedure-related stroke (p = 0.073). Procedure-related hemorrhagic complications were significantly associated with an unfavorable outcome (p = 0.003). Immediate contrast stasis in the venous phase was associated with complete occlusion during follow-up (p = 0.050).

Conclusion: The PED is a feasible and effective treatment to prevent rebleeding and achieve aneurysm occlusion, but it is associated with a substantial risk of periprocedural hemorrhage and ischemic complications in acute ruptured IAs. Therefore, the PED should be used selectively for acutely ruptured IAs. Additionally, adjunctive coiling might increase procedure-related stroke; however, it may reduce aneurysm rebleeding in acutely ruptured IAs. Patients with immediate contrast stasis in the venous phase were more likely to achieve total occlusion. A prospective study with a larger sample size should be performed to verify our results.

A novel score for evaluating cerebral aneurysms treated with flow diversion: 4F-flow diversion predictive score

Background and purpose

Although grading scales for angiography outcomes following cerebral aneurysm treatment with flow diversion have been published, physicians have not widely adopted these scales in practice. The aim of this study is to propose and validate a novel Flow diversion Predictive Score (4F-FPS) grading scale based on previously established scales that is simple and reliable.

Methods

We retrospectively analyzed consecutive patients who underwent endovascular treatment for cerebral aneurysms with flow diversion between January 2014 and September 2019. The included patients were randomly divided into the derivation and validation group in a 70/30 ratio, respectively. Aneurysms were classified as incomplete or complete occlusion based on final angiography outcomes. 4F-FPS was derived to predict aneurysm occlusion from multivariate logistic regression analyses in the derivation group and validated with previously published grading scales in the validation group.

Results

Overall, 662 patients [mean age, 53.8 years; 72.5% (480/662) female] with 662 aneurysms treated with the Pipeline^TM flow diverter were included [69.9% (463/662) derivation group, 30.1% (199/662) validation group]. The incidence of aneurysm occlusion was 82.7%. 4F-FPS demonstrated significant discrimination in 10-fold cross validation [mean receiver operating characteristic (ROC) area, 0.862 ± 0.055] and calibration (Cox & Snell R ², 0.251; Nagelkerke R ², 0.413) in the derivation group. The ROC area of 4F-FPS score in both the derivation and validation groups is the largest compared with previously published grading scales/scores (p < 0.05), which shows better sensitivity and specificity. The 4F-FPS score showed excellent prediction, discrimination, and calibration properties.

Conclusion

The 4F-FPS score is a simple and reliable tool to predict angiography outcome after flow diversion treatment. If widely adopted, it may provide a common language to be used in future reporting of flow diversion results for clinical trials and daily practice.

Clinical trial registration

http://www.clinicaltrials.gov. Unique identifier: NCT03831672.

Using angiographic parametric imaging-derived radiomics features to predict complications and embolization outcomes of intracranial aneurysms treated by pipeline embolization devices

BACKGROUND

Pipeline embolization devices (PEDs) have gained widespread popularity in the treatment of intracranial aneurysms (IAs). However, precise predictors of treatment outcomes are still lacking. This study aimed to use angiographic parametric imaging (API)-derived radiomics features to explore whether biomarkers extracted from immediate postprocedural digital subtraction angiography (DSA) were associated with complications and embolization outcomes of IAs treated with PED without adjunctive coils.

METHODS

Radiomic features were extracted from postprocedural DSA by API, and radiomics feature selection and radiomics score calculation were performed by the least absolute shrinkage and selection operator (LASSO) logistic regression. Angiographic findings and clinical characteristics were screened using stepwise multivariable logistic regression analysis to identify significant variables for predicting the complication endpoint. Radiomics feature selection and radiomics risk score (RadRS) calculations were performed by LASSO Cox regression. Univariate and multivariate Cox regression analyses were used to identify significant predictors for the occlusion endpoint.

RESULTS

We screened 281 observations for complications and 235 observations for embolization outcomes from IAs treated in our center using PED between June 2015 and July 2020. Multivariate regression analysis showed association of the radiomics score (p<0.01) and hypertension (p=0.04) with complications. RadRS (p<0.01), symptoms (p<0.01), and age (p=0.03) were predictors of embolization outcomes. Kaplan-Meier analysis revealed that symptomatic patients (p<0.01) and those with off-label IAs (p=0.03) had shorter intervals to complete occlusion.

CONCLUSIONS

Biomarkers extracted from immediate postprocedural DSA by API could be potential indicators for assessing treatment outcomes of IAs treated by PED without adjunctive coils.

Postoperative occlusion degree after flow-diverter placement with adjunctive coiling: analysis of complications

BACKGROUND

Although coiling with a flow diverter may provide immediate dome protection, no studies have evaluated the effect on complications of postoperative occlusion degree immediately postoperatively. The purpose of this study was to determine whether postoperative occlusion degree immediately after flow-diverter placement with adjunctive coiling was associated with complications.

METHODS

All patients' data were collected from the post-market multi-center cohort study of embolization of intracranial aneurysms with a pipeline embolization device (PED) in China (PLUS) registry. We divided patients into those treated with a PED alone (PED-only (PO) group), those treated with a PED with coils and incomplete occlusion (PED + coils + incomplete occlusion (PCIO) group), and those treated with a PED with coils and complete occlusion (PED + coils + complete occlusion (PCCO) group).

RESULTS

We evaluated 1171 consecutive patients with 1322 aneurysms treated with a PED: 685 aneurysms were treated with PO, 444 with PCIO, and 193 with PCCO. The PCCO group had a higher rate of aneurysm occlusion at the last follow-up than the PCIO and PO groups (P<0.0001). Multivariate analysis of the predictors of ischemic stroke and modified Rankin Scale score (mRS) deterioration showed that PCCO was an independent predictor of ischemic stroke (HR, 2.03; 95% CI, 1.12 to 3.67; P=0.019) and mRS deterioration (HR, 2.59; 95% CI, 1.57 to 4.26; P<0.0001).

CONCLUSIONS

Although postoperative complete occlusion with a PED and adjunctive coiling can increase the rate of aneurysm occlusion, this approach may also increase the risk of ischemic stroke and lead to poor postoperative functional outcomes.

Pipeline Embolization Device for Intracranial Aneurysms in a Large Chinese Cohort: Complication Risk Factor Analysis

During intracranial aneurysm embolization with the Pipeline embolization device (PED), ischemic and hemorrhagic complications have been observed in cases among Western populations. The postmarket multicenter registry study on the embolization of intracranial aneurysms with the PED in China, i.e., the PLUS study, was performed to assess real-world predictors of complications and functional outcomes in patients treated with the PED in a Chinese population. All patients with intracranial aneurysms who underwent embolization using the PED between November 2014 and October 2019 across 14 centers in China were included. The study endpoints included preoperative and early postoperative (< 30 days) functional outcomes (modified Rankin scale [mRS] scores) and complications related to PED treatment at early postoperative and follow-up time points (3-36 months). Multivariate analysis was performed to identify risk factors for complications. A total of 1171 consecutive patients (mean age, 53.9 ± 11.4; female, 69.6% [813/1171]) with 1322 aneurysms were included in the study. Hypertension, basilar artery aneurysms, and successful deployment after adjustment or unsuccessful device deployment were found to be independent predictors of ischemic stroke, while the use of the Flex PED and incomplete occlusion immediately after treatment were protective factors. An aneurysm size > 10 mm, distal anterior circulation aneurysms, and adjunctive coiling were found to be independent predictors of delayed aneurysm rupture, distal intraparenchymal hemorrhage, and neurological compression symptoms, respectively. The rate of PED-related complications in the PLUS study was similar to that in Western populations. The PLUS study identified successful deployment after adjustment or unsuccessful device deployment and the degree of immediate postoperative occlusion as novel independent predictors of PED-related ischemic stroke in a Chinese population. ClinicalTrial.gov Identifier: NCT03831672.

Mortality after treatment of intracranial aneurysms with the Pipeline Embolization Device

BACKGROUND

The Pipeline Embolization Device (PED) is reported to be a safe treatment tool for aneurysms. However, mortality occurs in a few cases, and this has not been clearly studied. We conducted a multicenter study to retrospectively evaluate the causes of, and risk factors for, mortality in patients with intracranial aneurysms treated with the PED.

METHODS

We retrospectively reviewed the prospectively maintained databases of patients with intracranial aneurysms treated by PED placement at 14 academic institutions from 2014 to 2019. Patients' data, including clinical and radiographic information, were analyzed with an emphasis on mortality-related complications.

RESULTS

A total of 1171 consecutive patients underwent 1319 PED procedures to treat 1322 intracranial aneurysms. The mortality rate was 1.5% (17/1171), and in 1.3% of the patients (15/1171), deaths were caused by delayed aneurysmal rupture, distal intraparenchymal hemorrhage, and neurological compression symptoms associated with PED procedures. Multivariate analysis showed that previous treatment (OR, 12.657; 95% CI, 3.189 to 50.227; P<0.0001), aneurysm size ≥10 mm (OR, 4.704; 95% CI, 1.297 to 17.068; P=0.019), aneurysm location (basilar artery) (OR, 10.734; 95% CI, 2.730 to 42.207; P=0.001), and current subarachnoid hemorrhage (OR, 4.505; 95% CI, 0.991 to 20.474; P=0.051) were associated with neurological complications resulting in mortality.

CONCLUSIONS

Delayed aneurysm rupture, distal intraparenchymal hemorrhage, and neurological compression were the main causes of mortality in patients with intracranial aneurysms treated with the PED. Large basilar aneurysms are associated with an increased risk of postoperative death and require increased attention and caution.

A comparative study of transradial versus transfemoral approach for flow diversion

PURPOSE

Data in neurointerventional literature is extremely limited regarding the safety and efficacy of flow diversion using transradial access (TRA). We aim to demonstrate the safety and efficacy of intracranial aneurysm treatment with the Pipeline Embolization Device (PED) using TRA compared to transfemoral access (TFA).

METHODS

We conducted a retrospective analysis of a prospectively maintained database and identified 79 consecutive patients who underwent neuroendovascular embolization for cerebral aneurysms using the PED from April 2018 through October 2019. Patients were divided into 2 groups: TRA (32 patients) and TFA (47 patients). A comparative analysis was performed between the two groups.

RESULTS

There was no significant difference in postoperative intracranial hemorrhage (p>.99), symptomatic ischemic stroke (p=.512), access site complications (p=.268), or other complications (p=.512). However, there was a significant increase in overall complications (14.9% vs. 0.0%, p=.038) and procedure duration (71.4 min ± 31.2 vs. 58.5 ± 20.3, p=.018) in the TFA group. There was no significant difference in complete occlusion at latest follow-up (19/25, 76.0% vs. 35/40, 87.5%; p=.311), 6-month follow-up (17/23, 73.9% vs. 33/38, 86.8%; p=.303), or 12-month follow-up (8/8, 100.0% vs. 5/6, 83.3%; p=.429). There was also no significant difference in rate of retreatment (p>.99), morbidity (p=.512), mortality (p>.99), latest follow-up (p=.985), or loss of follow-up (p=.298).

CONCLUSIONS

The feasibility and efficacy of flow diversion with the PED via TRA for the treatment of intracranial aneurysms is comparable to TFA. Widespread adoption of this approach may be facilitated by improvements in device navigation and manipulation via radial-specific engineering.

Factors associated with the new appearance of cerebral microbleeds after endovascular treatment for unruptured intracranial aneurysms

PURPOSE

Endovascular treatment of unruptured intracranial aneurysms may increase cerebral microbleeds (CMBs) in postprocedural T2*-weighted MRIs, which may be a risk for future intracerebral hemorrhage. This study examined the characteristics of postprocedural CMBs and the factors that cause their increase.

METHODS

The patients who underwent endovascular treatment for unruptured intracranial aneurysms from April 2016 to February 2018 were retrospectively analyzed. Treatment techniques for endovascular treatment included simple coiling, balloon-assisted coiling, stent-assisted coiling, or flow diverter placement. To evaluate the increase in CMBs, a head MRI including diffusion-weighted imaging and T2*-weighted MRIs was performed on the preprocedural day; the first postprocedural day; and at 1, 3, and 6 months after the procedure.

RESULTS

Among the 101 aneurysms that were analyzed, 38 (37.6%) showed the appearance of new CMBs. In the multivariate analysis examining the causes of the CMB increases, chronic kidney disease, a higher number of preprocedural CMBs, and a higher number of diffusion-weighted imaging-positive lesions on the first postprocedural day were independent risk factors. Furthermore, a greater portion of the increased CMBs was found in cortical and subcortical lesions of the treated vascular perfusion area within 1 month after the procedure.

CONCLUSION

In endovascular treatment for unruptured intracranial aneurysms, CMBs tended to increase in patients with small vessel disease before the procedure, and it was also implicated in hemorrhagic changes after periprocedural microinfarction.

Pipeline Embolization device for intracranial aneurysms in a large Chinese cohort: factors related to aneurysm occlusion

Background and Purpose:

The Pipeline Embolization Device (PED, Covidien/Medtronic) is widely used to treat intracranial aneurysms. This PED in China post-market multi-center registry study (PLUS) investigated safety and effectiveness of the PED for intracranial aneurysms in the Chinese population.

Methods:

This was a panoramic, consecutive, real-world cohort registry study. Patients treated with PED with or without coils between November 2014 and October 2019 at 14 centers in China were included, and those treated by parent vessel occlusion or other stents were excluded. Study outcomes included angiographic evaluation of aneurysm occlusion, complications, in-stent stenosis, and predictors of aneurysm occlusion. A central committee reviewed all imaging and endpoint events.

Results:

In total, 1171 patients with 1322 intracranial aneurysms were included. The total occlusion rate was 81.4% (787/967) at mean follow-up of 8.96 ± 7.50 months, with 77.1% (380/493) occlusion in the PED alone and 85.9% (407/474) in the PED plus coiling group. On multi-variate analysis, female sex, hyperlipidemia, vertebral aneurysms, PED plus coiling, and blood flow detained to venous phase were significant predictors of aneurysm occlusion. In posterior circulation cohort, there was no variable associated with aneurysm occlusion. In-stent stenosis predictors included current smoking and cerebral sclerosis/stenosis.

Conclusion:

In the largest series on PED of multi-center date of China, data suggest that treatment with the flow-diverting PED in intracranial aneurysms was efficacious. The treatment of PED combined coiling and blood flow detained to venous phase after PED implant were associated with aneurysmal occlusion. The occlusion rate of vertebral aneurysms was higher than other location aneurysms.

Clinical Trial Registration:

ClinicalTrials.gov identifier: NCT03831672.

Comparison of PED and FRED flow diverters for posterior circulation aneurysms: a propensity score matched cohort study

BACKGROUND

Flow diversion is a common endovascular treatment for cerebral aneurysms, but studies comparing different types of flow diverters are scarce.

OBJECTIVE

To perform a propensity score matched cohort study comparing the Pipeline Embolization Device (PED) and Flow Redirection Intraluminal Device (FRED) for posterior circulation aneurysms.

METHODS

Consecutive aneurysms of the posterior circulation treated at 25 neurovascular centers with either PED or FRED were collected. Propensity score matching was used to control for age, duration of follow-up imaging, adjunctive coiling, and aneurysm location, size, and morphology; previously ruptured aneurysms were excluded. The two devices were compared for the following outcomes: procedural complications, aneurysm occlusion, and functional outcome.

RESULTS

A total of 375 aneurysms of the posterior circulation were treated in 369 patients. The PED was used in 285 (77.2%) and FRED in 84 (22.8%) procedures. Aneurysms treated with the PED were more commonly fusiform and larger than those treated with FRED. To account for these important differences, propensity score matching was performed resulting in 33 PED and FRED unruptured aneurysm pairs. No differences were found in occlusion status and neurologic thromboembolic or hemorrhagic complications between the two devices. The proportion of patients with favorable functional outcome was higher with FRED (100% vs 87.9%, p=0.04).

CONCLUSION

Comparative analysis of PED and FRED for the treatment of unruptured posterior circulation aneurysms did not identify significant differences in aneurysm occlusion or neurologic complications. Variations in functional outcomes warrant additional investigations.

Preclinical safety and efficacy evaluation of the Pipeline Vantage Embolization Device with Shield Technology

BACKGROUND

The Pipeline Vantage Embolization Device with Shield Technology is a next generation flow diverter developed to improve aneurysm occlusion and implant endothelialization in addition to lowering thrombogenicity. We report here the in vivo biocompatibility and in vitro hemocompatibility performance of the Pipeline Vantage Embolization Device with Shield Technology (Vantage) compared with the Pipeline Flex Embolization Device (Flex).

METHODS

Biocompatibility (via histology), aneurysm occlusion and vessel patency (via angiography), and endothelial coverage (via scanning electron microscopy (SEM)) for the Vantage and Flex devices were assessed in the rabbit elastase aneurysm model at 90 days (n=29) and 180 days (n=27). In vitro thrombogenicity for Flex and Vantage (n=16) was assessed using a human blood flow loop model at low heparin concentration (0.6 U/mL) with thrombin generation, platelet activation and thrombus visualization as outputs.

RESULTS

Raymond Roy Occlusion Classification grade 1 was higher for Vantage (61%) compared with Flex (46%), but was not statistically significant (p>0.05). All branch vessels were patent. Histological measures for both devices were similar (p>0.05). Endothelial coverage of the implant was significantly better for Vantage compared with Flex (p<0.05). In vitro measurements of thrombin generation (thrombin-antithrombin complex (µg/mL): Vantage 0.49±0.45; Flex 10.57±9.84) and platelet activation (β-thromboglobulin (IU/µl): Vantage 0.41±0.19; Flex 4.14±2.38) were both statistically lower (p<0.05) for Vantage compared with Flex. High resolution microscopy showed less accumulation of thrombus on Vantage as compared with Flex.

CONCLUSION

Vantage improved aneurysm occlusion and implant endothelialization and had significantly lower thrombogenicity as compared with Flex, while preserving the biocompatibility safety profile of Flex.

Advances in endovascular aneurysm management: flow modulation techniques with braided mesh devices

Flow diverters and flow disruption technology, alongside nuanced endovascular techniques, have ushered in a new era of treating cerebral aneurysms. Here, we provide an overview of the latest flow modulation devices and highlight their clinical applications and outcomes.

First clinical experience with the new Surpass Evolve flow diverter: technical and clinical considerations

Objective

To describe the results in patients treated with the Surpass Evolve (SE) device, the new generation of Surpass flow diverters.

Methods

Twenty-five consecutive patients (20 women, average age 58 years), with anterior or posterior circulation aneurysms treated with SEs in two early-user centers, were included. Device properties and related technical properties, imaging and clinical follow-up data, and intraprocedural, early (<30 days) and delayed (>30 days) neurological complications, further divided into minor (silent/non-permanent) and major (permanent) complications, were recorded and analyzed.

Results

Twenty-nine SEs were successfully implanted in all subjects to treat 26 aneurysms using an 0.027" microcatheter with an average of 1.2 stents per patient. No intraprocedural thromboembolic or hemorrhagic complications were seen. At clinical follow-up, 24/25 (96%) patients had a modified Rankin Score of 0–2. Mortality was 0%. Imaging follow-up, available in 22/25 (88%) patients (median follow-up time 4 months), showed a complete aneurysm occlusion in 13/23 (57%) imaged lesions. Minor, transitory neurological deficits were recorded in 5/25 (20%) patients. One (4%) major complication was seen in one patient (4%) with a left-sided hemispheric stroke on postprocedural day 4 due to an acute stent thrombosis.

Conclusions

Preliminary experience in patients demonstrates a good performance of the SE. This newly designed implant maintains the engineering characteristics of Surpass flow diverters, including precise placement due to its lower foreshortening and a high mesh density, yet can be deployed through a significantly lower-profile delivery system.