Cangrelor for neurointerventional procedures: A systematic review.

Thromboembolism is a complication of neurointerventional procedures that requires patients to be placed under antiplatelet therapy. Current options for antiplatelet therapies have a delayed onset of action that prevents a rapid door to puncture transition for patents presenting in acute settings. Cangrelor (Kengreal, Chiesi, USA) is an intravenous P2Y12 platelet inhibitor approved in percutaneous coronary interventions that has an immediate onset of action and half-life between 2 and 6 min. Thus, the goal of this study is to report on the safety, effectiveness, and indications for using Cangrelor in neurointerventional procedures. A systematic review of studies describing the use of Cangrelor in neurointervention was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The search was conducted on PubMed, Ovid Medline, and Embase databases through June 2023. Seventeen studies with 314 patients met inclusion criteria. The most common indication for Cangrelor use was acute ischemic strokes: 70% followed by aneurysms 27.4%. The Infusion protocol varied from 5 to 30 µg/kg bolus and 1 to 4 µg/kg/min infusion with 30 µg/kg bolus and 4 µg/kg/min infusion being reported in 64.7% of studies. Intra-operative platelet reacting unit levels were below 200 in all the studies that reported it, and the percentage of hemorrhagic, thromboembolic, and deaths occurrence in this patient cohort was respectively 11.1%, 4.8%, and 8.6%. Cangrelor appears to be a promising P2Y12 platelet inhibitor for neurointerventional procedures. However, large, randomized trials are needed to determine the full range of its effects in neurointerventional procedures.

Novel usage of everolimus-eluting coronary stent for intracranial atherosclerotic disease: a technical report and case series.

Objectives: This report describes the use of an Everolimus-eluting stent (Xience Skypoint stent) for the treatment of medically-refractory ICAD. Design: Retrospective, case-series. Setting: In-hospital patients. Participants: All patients in this report had a history of stroke secondary to ICAD. All patients failed aggressive medical treatments and had recurrence of symptoms despite anticoagulation or dual-antiplatelet therapy plus a statin. Diagnostic angiogram in each case showed severe vessel stenosis, therefore patients were recommended for intracranial artery stenting. Main outcome measures: Technical feasibility of deploying Xience Skypoint stent for treatmet of ICAD. Results: The Xience Skypoint stent was safely and effectively deployed in the vertebral artery (x1) and the internal carotid artery (x2) using trans-ulnar (x1), trans-radial (x1), and trans-femoral (x1) approaches without the use of an intermediate catheter. Conclusion: Second-generation EES such as Xience Skypoint may be utilized for treatment of medically-refractory ICAD. This technical report serves as a proof of concept for further studies analysing long-term safety and efficacy of such stents for treatment of ICAD.

Endovascular Treatment of Giant Intracranial Aneurysms.

Objective Giant intracranial aneurysms (GIAs) are associated with a high risk of rupture and have a high mortality rate when they rupture (65-100%). The traditional microsurgical approach to secure these lesions is challenging, and as such endovascular embolization has been increasingly selected as a treatment option. Methods We performed a retrospective analysis of consecutive patients with ruptured and unruptured GIAs at three medical centers from October 2008 to April 2016. Clinical follow-up and digital subtraction angiography were conducted at six months post-treatment. Chi-square analysis was used to determine differences in outcomes between anterior and posterior circulation aneurysms and if a pipeline embolization device (PED) provided favorable outcomes in unruptured GIAs. Results A total of 45 consecutive patients (mean/median age = 57/59; range: 16-82 years) were included. The mean/median aneurysm size was 29.9/28.3 mm (range: 25-50 mm). Eight (18%) patients presented with aneurysmal subarachnoid hemorrhage and 37 (82%) with unruptured GIAs. Twenty-eight (62%) were treated with a PED: 11 (24.4%) with one PED, 1 (2.2%) with PED + coils, 11 (24.4%) with more than one PED, and 5 (13.5%) with multiple PED + coils. The overall mortality rate was 3/45 (6.7%). No deaths were procedure-related. Five (11.1%) patients experienced ischemic stroke but only 2 had a 90-day modified Rankin Scale (mRS) score of ≥3. Of 33 patients available for six-month angiography, Raymond scale (RS) scores were 1, 2, and 3 for 23/45 (70%), 7/45 (20.9%), and 3/45 (9.1%), respectively. Chi-square test demonstrated that overall, anterior circulation GIAs had better clinical (mRS score) and radiographic (RS score) outcomes than posterior GIAs. PED alone provided similar clinical mRS outcomes but had a higher rate of complete occlusion at six months compared with PED + coils and coils alone in unruptured GIAs (p < 0.05). Conclusions Endovascular embolization using PED or PED + coils appears to be a moderately safe and effective treatment option for patients with GIAs.

Versatile use of catheter systems for deployment of the Pipeline embolization device: a comparison of biaxial and triaxial catheter systems.

BACKGROUND: A Pipeline embolization device (PED; Medtronic, Dublin, Ireland) can be deployed using either a biaxial or a triaxial catheter delivery system. OBJECTIVE: To compare the use of these two catheter delivery systems for intracranial aneurysm treatment with the PED. METHODS: A retrospective study of patients undergoing PED deployment with biaxial or triaxial catheter systems between 2014 and 2016 was conducted. Experienced neurointerventionalists performed the procedures. Patients who received multiple PEDs or adjunctive coils were excluded. The two groups were compared for PED deployment time, total fluoroscopy time, patient radiation exposure, complications, and cost. RESULTS: Eighty-two patients with 89 intracranial aneurysms were treated with one PED each. In 49 cases, PEDs were deployed using biaxial access; triaxial access was used in 33 cases. Time (min) from guide catheter run to PED deployment was significantly shorter in the biaxial group (24.0±18.7 vs 38.4±31.1, P=0.006) as was fluoroscopy time (28.8±23.0 vs 50.3±27.1, P=0.001). Peak radiation skin exposure (mGy) in the biaxial group was less than in the triaxial group (1243.7±808.2 vs 2074.6±1505.6, P=0.003). No statistically significant differences were observed in transient and permanent complication rates or modified Rankin Scale scores at 30 days. The triaxial access system cost more than the biaxial access system (average $3285 vs $1790, respectively). Occlusion rates at last follow-up (mean 6 months) were similar between the two systems (average 88.1%: biaxial, 89.2%: triaxial). CONCLUSION: Our results indicate near-equivalent safety and effectiveness between biaxial and triaxial approaches. Some reductions in cost and procedure time were noted with the biaxial system.

The Pipeline Embolization Device: Changes in Practice and Reduction of Complications in the Treatment of Anterior Circulation Aneurysms in a Multicenter Cohort.

BACKGROUND: The Pipeline Embolization Device (PED; Medtronic, Dublin, Ireland) has become an important tool for the treatment of cerebral aneurysms. Since FDA approval, there are ongoing efforts to increase aneurysm occlusion rates and reduce the incidence of complications. OBJECTIVE: To assess aneurysm occlusion and complication rates over time. METHODS: Retrospective analysis of consecutive anterior circulation aneurysms treated with a single PED between 2011 and 2016 at 3 academic institutions in the US was performed. Factors contributing to changes in aneurysm occlusion and complication rates over time were identified and evaluated. RESULTS: A total of 284 procedures were performed on 321 anterior circulation aneurysms in 284 patients. At a median follow-up of 13 mo (mean 18 mo), complete or near complete occlusion (>90%) was achieved in 85.9% of aneurysms. There was no significant change in aneurysm occlusion rate or procedure length over time. Thromboembolic complication occurred in 8.1% of procedures, and there was a trend toward decreased incidence from 16.3% in 2011/2012 to 3.3% in 2016 (P = .14). Hemorrhagic complications significantly decreased from 8.2% in 2011/2012 to 0 to 1.0% in 2014-2016 (P = .1). CONCLUSION: We report a notable drop in the rate of hemorrhagic and to a lesser extent thromboembolic complications with increased experience with PED in a multicenter cohort. Multiple factors are believed to contribute to this drop, including the evolved interpretation of platelet function testing, the switching of clopidogrel nonresponders to ticagrelor, and the reduced use of adjunctive coiling.

Submaximal Angioplasty for Symptomatic Intracranial Atherosclerotic Disease: A Meta-Analysis of Peri-Procedural and Long-Term Risk.

BACKGROUND: Symptomatic intracranial atherosclerotic disease (ICAD) is an important cause of stroke. Although the high periprocedural risk of intracranial stenting from recent randomized studies has dampened enthusiasm for such interventions, submaximal angioplasty without stenting may represent a safer endovascular treatment option. OBJECTIVE: To examine the periprocedural and long-term risks associated with submaximal angioplasty for ICAD based on the available literature. METHODS: All English language studies of intracranial angioplasty for ICAD were screened. Inclusion criteria were as follows: ≥ 5 patients, intervention with submaximal angioplasty alone, and identifiable periprocedural (30-d) outcomes. Analysis was co-nducted to identify the following: 1) periprocedural risk of any stroke (ischemic or hemorrh-agic) or death, and 2) stroke in the territory of the target vessel and fatal stroke beyond 30 d. Mixed effects logistic regression was used to summarize event rates. Funnel plot and rank correlation tests were employed to detect publication bias. The relative risk of periprocedural events from anterior vs posterior circulation disease intervention was also examined. RESULTS: A total of 9 studies with 408 interventions in 395 patients met inclusion criteria. Six of these studies included 113 posterior circulation interventions. The estimated pooled rate for 30-d stroke or death following submaximal angioplasty was 4.9% (95% CI: 3.2%-7.5%), whereas the estimated pooled rate beyond 30 d was 3.7% (95% CI: 2.2%-6.0%). There was no statistical difference in estimated pooled rate for 30-d stroke or death between patients with anterior (4.8%, 95% CI: 2.8%-7.9%) vs posterior (5.3%, 95% CI: 2.4%-11.3%) circulation disease (P > .99). CONCLUSION: Submaximal angioplasty represents a potentially promising intervention for symptomatic ICAD.

Adenosine-Induced Cardiac Arrest for Transvenous Embolization of Midbrain Arteriovenous Malformation.

BACKGROUND AND IMPORTANCE: Few studies describe the use of adenosine-induced cardiac systole for treatment of cerebrovascular pathologies. We describe a midbrain arteriovenous malformation (AVM) treated with transvenous embolization using adenosine-induced asystole to achieve transient systemic hypotension with the purpose of furthering discussion on the technique and operative considerations for adenosine use in endovascular AVM treatments. CLINICAL PRESENTATION: A 29-yr-old man presented with sudden onset of severe bilateral headache, blurred vision, and numbness on the right side of his face and tongue. Noncontrast head computed tomography revealed fourth ventricle hemorrhage. Diagnostic cerebral angiography revealed a high-flow midbrain AVM with a posterior wall perforator from the basilar artery terminus and a draining vein into the straight sinus. Transarterial AVM embolization was successful. The patient was discharged with no residual neurological deficits but returned 1 wk later with slurred speech and left-sided dysmetria. Repeat angiography revealed partial AVM filling. Attempts at transarterial embolization were unsuccessful. Thus, transvenous AVM embolization with adenosine-induced cardiac asystole and systemic hypotension was performed. A total of 60 mg of adenosine was administered, followed by 2 additional doses of 60 and 40 mg; and complete cardiac asystole with a mean arterial pressure of 40 mmHg was maintained, resulting in successful embolization of the AVM. No residual filling was visualized on postembolization arterial angiography runs. The patient was neurologically stable and discharged on postoperative day 2. CONCLUSION: With appropriate and safe dosing, adenosine-induced asystole and systemic hypotension may be a feasible, safe option to reduce flow and assist endovascular transvenous embolization of high-flow AVMs.

Relationship of Grit and Resilience to Burnout Among U.S. Neurosurgery Residents.

INTRODUCTION: Studies have begun investigating grit (continued fortitude in the face of hardship) and resilience (ability to recover from a setback) and their relationship to burnout (emotional exhaustion [EE] caused by prolonged stress or frustration) within medicine. We investigated the prevalence of burnout among neurosurgery residents and aimed to determine the relationship among burnout, grit, and resilience. METHODS: We surveyed U.S. neurosurgical residents to perform a discretional analysis of prevalence of burnout. Multivariate analysis was performed to determine which variables were associated with higher and lower levels of EE, depersonalization (DP), personal accomplishment (PA), burnout, grit, and resilience. RESULTS: Of 1385 U.S. neurosurgery residents, 427 (30.8%) responded to our survey. Burnout prevalence was 33.0% (95% confidence interval, 28.6%-37.7%). High grit was associated with U.S. graduates (P = 0.006), married residents (P = 0.025), and fewer social/personal stressors (P = 0.003). Lower resilience was associated with female sex (P = 0.006), whereas higher resilience was associated with international medical graduates (P = 0.017) and fewer social/personal stressors (P = 0.005). High burnout was associated with greater social/personal stressors (P = 0.002), clinical rotations (P = 0.001), and lack of children (P = 0.016). There were positive correlations between EE and DP and among PA, grit, and resilience. There were negative correlations for EE and DP with PA, grit, and resilience and between grit/resilience and burnout. CONCLUSIONS: There is an inverse relationship between grit/resilience and burnout. Increased social/personal stressors are associated with increased levels of burnout and decreased grit and resilience. Grit and resilience are higher when social and personal stressors are decreased, indicating that these characteristics may fluctuate over time.

High-Definition Zoom Mode: A High Resolution X-ray Microscope for Neurointerventional Treatment Procedures.

BACKGROUND AND PURPOSE: Visualization of structural details of treatment devices during neurointerventional procedures can be challenging. A new true two-resolution imaging X-ray detector system features a 194 µm pixel conventional flat-panel detector (FPD) mode and a 76 µm pixel high-resolution high-definition (Hi-Def) zoom mode in one detector panel. The Hi-Def zoom mode was developed for use in interventional procedures requiring superior image quality over a small field of view (FOV). We report successful use of this imaging system during intracranial aneurysm treatment in 1 patient with a Pipeline-embolization device and 1 patient with a low-profile visualized intramural support (LVIS Blue) device plus adjunctive coiling. METHODS: A guide catheter was advanced from the femoral artery insertion site to the proximity of each lesion using standard FPD mode. Under magnified small FOV Hi-Def imaging mode, an intermediate catheter and microcatheters were guided to the treatment site, and the PED and LVIS Blue plus coils were deployed. Radiation doses were tracked intraprocedurally. RESULTS: Critical details, including structural changes in the PED and LVIS Blue and position and movement of the microcatheter tip within the coil mass, were more readily apparent in Hi-Def mode. Skin-dose mapping indicated that Hi-Def mode limited radiation exposure to the smaller FOV of the treatment area. CONCLUSIONS: Visualization of device structures was much improved in the high-resolution Hi-Def mode, leading to easier, more controlled deployment of stents and coils than conventional FPD mode.

Vascular Anatomy and Not Age is Responsible for Increased Risk of Complications in Symptomatic Elderly Patients Undergoing Carotid Artery Stenting.

BACKGROUND: Various studies have suggested that age ≥80 years is associated with a higher rate of complications after carotid artery stenting (CAS). The Buffalo Risk Assessment Scale (BRASS) predicts complications in symptomatic patients undergoing CAS. Application of the BRASS has shown the ability to improve patient selection. We used the BRASS system to evaluate whether the higher rate of complications associated with CAS in the elderly is related to vascular anatomy. METHODS: A retrospective review of CAS was performed at our institution over 7 years. Demographic information, anatomic characteristics, BRASS categorization, and outcome measures were compared between elderly (≥80 years) and younger patients (<80 years). RESULTS: The study included 447 patients: 335 patients (75%) <80 years and 112 patients (25%) ≥80 years. There were significantly more elderly patients in the high-risk BRASS category (P < 0.01), and more young patients in the low-risk BRASS category (P = 0.04). The complication rates in the 2 groups were similar. Older patients were more likely to harbor complex vascular anatomy: they had significantly higher rates of types II and III aortic arches (P = 0.01 and P < 0.01, respectively), higher percentage of tortuous carotid vessels (P < 0.01), and higher rates of hostile anatomy for deployment of distal embolic protection devices (P = 0.02). CONCLUSIONS: Complex vascular anatomy, rather than age, is the key factor behind the higher CAS-associated complication rate in the elderly. Complications can be avoided through proper patient selection and stratifying patients based on anatomic characteristics, which can be achieved through the BRASS scoring system.

Accredited Endovascular Surgical Neuroradiology Programs: Current Specialty Composition and Academic Impact Using the h Index.

BACKGROUND: Concerns exist that neurosurgery might fail to lead the field of endovascular surgical neuroradiology (ESN), as other specialties are allowed to train and practice ESN. This study aimed to assess the current breakdown of specialties and their relative academic productivity in accredited ESN fellowship programs. METHODS: A list of fellowship programs was obtained from the Accreditation Council for Graduate Medical Education and Committee on Advanced Subspecialty Training directories. Primary specialty (i.e., residency) training for each faculty member in these programs was determined using information provided by the programs. A bibliometric search was performed for each member using Web of Science (Clarivate Analytics, Philadelphia, Pennsylvania, USA). Cumulative and ESN-specific h indices were calculated; h indices were compared between each specialty group and between international medical graduates and US medical graduates, regardless of specialty training. RESULTS: Thirty-one ESN fellowship programs with 88 faculty members were included. Neurosurgeons constituted 61.4% (n = 54) of the total ESN faculty, followed by radiologists with 30.7% (n = 27), and neurologists with 7.9% (n = 7). The mean ESN-specific h index for neurosurgery-trained ESN faculty was 16.2 ± 14.6 compared with 14.4 ± 10.9 for radiologists and 13.0 ± 12.6 for neurologists (P = 0.76). There were 12 IMGs and 76 USMGs. The mean ESN-specific h index was greater for IMGs than USMGs, 24.7 ± 14.3 versus 14.0 ± 12.7 (P = 0.008), respectively. CONCLUSIONS: Neurosurgery is leading the ESN field in numbers; however, the h index is not significantly different among ESN faculty based on primary training. The number of IMGs is relatively small, yet IMGs have significantly higher mean h indices.

Endovascular thrombectomy in pediatric patients with large vessel occlusion.

BACKGROUND: Pediatric acute ischemic stroke with underlying large vessel occlusion is a rare disease with significant morbidity and mortality. There is a paucity of data about the safety and outcomes of endovascular thrombectomy in these cases, especially with modern devices. METHODS: We conducted a retrospective review of all pediatric stroke patients who underwent endovascular thrombectomy in nine US tertiary centers between 2008 and 2017. RESULTS: Nineteen patients (63.2% male) with a mean (SD) age of 10.9(6) years and weight 44.6 (30.8) kg were included. Mean (SD) NIH Stroke Scale (NIHSS) score at presentation was 13.9 (5.7). CT-based assessment was obtained in 88.2% of the patients and 58.8% of the patients had perfusion-based assessment. All procedures were performed via the transfemoral approach. The first-pass device was stentriever in 52.6% of cases and aspiration in 36.8%. Successful revascularization was achieved in 89.5% of the patients after a mean (SD) of 2.2 (1.5) passes, with a mean (SD) groin puncture to recanalization time of 48.7 (37.3) min (median 41.5). The mean (SD) reduction in NIHSS from admission to discharge was 10.2 (6.2). A good neurological outcome was achieved in 89.5% of the patients. One patient had post-revascularization seizure, but no other procedural complications or mortality occurred. CONCLUSIONS: Endovascular thrombectomy is safe and feasible in selected pediatric patients. Technical and neurological outcomes were comparable to adult literature with no safety concerns with the use of standard adult devices in patients as young as 18 months. This large series adds to the growing literature but further studies are warranted.

Transvenous embolization of thalamic arteriovenous malformation under transient cardiac standstill.

Transvenous embolization (TE) has been increasingly applied for arteriovenous malformation (AVM) treatment. Transient cardiac standstill (TCS) has been described in cerebrovascular surgery but is uncommon for endovascular embolization. The authors present a patient with a ruptured thalamic AVM in whom both techniques were applied simultaneously. Surgery was considered, but the patient refused. Transarterial embolization was performed with an incomplete result. The deep-seated draining vein provided sole access to the AVM. A microcatheter was advanced into the draining vein. Under TCS, achieved with rapid ventricular pacing, complete AVM embolization was obtained. One-year magnetic resonance imaging and cerebral angiography demonstrated no residual AVM.The video can be found here: https://youtu.be/CAzb9md_xBU.

Endovascular Recanalization of Symptomatic Intracranial Arterial Stenosis Despite Aggressive Medical Management.

BACKGROUND: The optimal management of intracranial arterial stenosis is unclear, particularly in patients who have failed medical management. We report a multicenter real-world experience of endovascular recanalization of intracranial atherosclerotic stenosis refractory to aggressive medical therapy. METHODS: Retrospective multicenter case series of consecutive endovascularly treated patients presenting with symptomatic (transient ischemic attack [TIA] or stroke) intracranial stenosis who had failed medical therapy. Patients were divided into 2 groups: patients with recurrent TIA or stroke despite medical management (group 1) versus patients presenting with a stroke and worsening symptoms (progressive or crescendo stroke) despite medical management (group 2). RESULTS: A total of 101 patients were treated in 8 stroke centers from August 2009 to May 2017. Sixty-nine presented with recurrent TIA or stroke and 32 with stroke and worsening symptoms. Successful recanalization was achieved in 84% of patients. Periprocedural stroke occurred in 3 patients and 2 had a recurrent ischemic stroke at the 90-day follow-up. Symptomatic intraparenchymal hemorrhage secondary to reperfusion injury occurred in 3 patients and 1 had a hemorrhagic stroke after discharge. There were 2 periprocedural perforations that resulted in death. At 90 days, 86% of patients (64/74) did not have a recurrence of stroke and the 90-day cumulative ischemic stroke rate was 6.7% with 90-day mortality of 11.2%. The 90-day favorable outcome (modified Rankin Scale score, ≤2) rate was 77.5%. CONCLUSIONS: Endovascular recanalization of unstable intracranial atherosclerotic stenosis in patients who have failed medical therapy is feasible. Future randomized trials need to determine if recanalization is of any value for this population.

Biomarkers from circulating neutrophil transcriptomes have potential to detect unruptured intracranial aneurysms.

BACKGROUND: Intracranial aneurysms (IAs) are dangerous because of their potential to rupture and cause deadly subarachnoid hemorrhages. Previously, we found significant RNA expression differences in circulating neutrophils between patients with unruptured IAs and aneurysm-free controls. Searching for circulating biomarkers for unruptured IAs, we tested the feasibility of developing classification algorithms that use neutrophil RNA expression levels from blood samples to predict the presence of an IA. METHODS: Neutrophil RNA extracted from blood samples from 40 patients (20 with angiography-confirmed unruptured IA, 20 angiography-confirmed IA-free controls) was subjected to next-generation RNA sequencing to obtain neutrophil transcriptomes. In a randomly-selected training cohort of 30 of the 40 samples (15 with IA, 15 controls), we performed differential expression analysis. Significantly differentially expressed transcripts (false discovery rate < 0.05, fold change ≥ 1.5) were used to construct prediction models for IA using four well-known supervised machine-learning approaches (diagonal linear discriminant analysis, cosine nearest neighbors, nearest shrunken centroids, and support vector machines). These models were tested in a testing cohort of the remaining 10 neutrophil samples from the 40 patients (5 with IA, 5 controls), and model performance was assessed by receiver-operating-characteristic (ROC) curves. Real-time quantitative polymerase chain reaction (PCR) was used to corroborate expression differences of a subset of model transcripts in neutrophil samples from a new, separate validation cohort of 10 patients (5 with IA, 5 controls). RESULTS: The training cohort yielded 26 highly significantly differentially expressed neutrophil transcripts. Models using these transcripts identified IA patients in the testing cohort with accuracy ranging from 0.60 to 0.90. The best performing model was the diagonal linear discriminant analysis classifier (area under the ROC curve = 0.80 and accuracy = 0.90). Six of seven differentially expressed genes we tested were confirmed by quantitative PCR using isolated neutrophils from the separate validation cohort. CONCLUSIONS: Our findings demonstrate the potential of machine-learning methods to classify IA cases and create predictive models for unruptured IAs using circulating neutrophil transcriptome data. Future studies are needed to replicate these findings in larger cohorts.

Outcome prediction of intracranial aneurysm treatment by flow diverters using machine learning.

OBJECTIVEFlow diverters (FDs) are designed to occlude intracranial aneurysms (IAs) while preserving flow to essential arteries. Incomplete occlusion exposes patients to risks of thromboembolic complications and rupture. A priori assessment of FD treatment outcome could enable treatment optimization leading to better outcomes. To that end, the authors applied image-based computational analysis to clinically FD-treated aneurysms to extract information regarding morphology, pre- and post-treatment hemodynamics, and FD-device characteristics and then used these parameters to train machine learning algorithms to predict 6-month clinical outcomes after FD treatment.METHODSData were retrospectively collected for 84 FD-treated sidewall aneurysms in 80 patients. Based on 6-month angiographic outcomes, IAs were classified as occluded (n = 63) or residual (incomplete occlusion, n = 21). For each case, the authors modeled FD deployment using a fast virtual stenting algorithm and hemodynamics using image-based computational fluid dynamics. Sixteen morphological, hemodynamic, and FD-based parameters were calculated for each aneurysm. Aneurysms were randomly assigned to a training or testing cohort in approximately a 3:1 ratio. The Student t-test and Mann-Whitney U-test were performed on data from the training cohort to identify significant parameters distinguishing the occluded from residual groups. Predictive models were trained using 4 types of supervised machine learning algorithms: logistic regression (LR), support vector machine (SVM; linear and Gaussian kernels), K-nearest neighbor, and neural network (NN). In the testing cohort, the authors compared outcome prediction by each model trained using all parameters versus only the significant parameters.RESULTSThe training cohort (n = 64) consisted of 48 occluded and 16 residual aneurysms and the testing cohort (n = 20) consisted of 15 occluded and 5 residual aneurysms. Significance tests yielded 2 morphological (ostium ratio and neck ratio) and 3 hemodynamic (pre-treatment inflow rate, post-treatment inflow rate, and post-treatment aneurysm averaged velocity) discriminants between the occluded (good-outcome) and the residual (bad-outcome) group. In both training and testing, all the models trained using all 16 parameters performed better than all the models trained using only the 5 significant parameters. Among the all-parameter models, NN (AUC = 0.967) performed the best during training, followed by LR and linear SVM (AUC = 0.941 and 0.914, respectively). During testing, NN and Gaussian-SVM models had the highest accuracy (90%) in predicting occlusion outcome.CONCLUSIONSNN and Gaussian-SVM models incorporating all 16 morphological, hemodynamic, and FD-related parameters predicted 6-month occlusion outcome of FD treatment with 90% accuracy. More robust models using the computational workflow and machine learning could be trained on larger patient databases toward clinical use in patient-specific treatment planning and optimization.

Computer-Assisted Three-Dimensional Morphology Evaluation of Intracranial Aneurysms.

OBJECTIVE: Precise morphologic evaluation is important for intracranial aneurysm (IA) management. At present, clinicians manually measure the IA size and neck diameter on 2-dimensional (2D) digital subtraction angiographic (DSA) images and categorize the IA shape as regular or irregular on 3-dimensional (3D)-DSA images, which could result in inconsistency and bias. We investigated whether a computer-assisted 3D analytical approach could improve IA morphology assessment. METHODS: Five neurointerventionists evaluated the size, neck diameter, and shape of 39 IAs using current and computer-assisted 3D approaches. In the computer-assisted 3D approach, the size, neck diameter, and undulation index (UI, a shape irregularity metric) were extracted using semiautomated reconstruction of aneurysm geometry using 3D-DSA, followed by IA neck identification and computerized geometry assessment. RESULTS: The size and neck diameter measured using the manual 2D approach were smaller than computer-assisted 3D measurements by 2.01 mm (P < 0.001) and 1.85 mm (P < 0.001), respectively. Applying the definitions of small IAs (<7 mm) and narrow-necked IAs (<4 mm) from the reported data, interrater variation in manual 2D measurements resulted in inconsistent classification of the size of 14 IAs and the necks of 19 IAs. Visual inspection resulted in an inconsistent shape classification for 23 IAs among the raters. Greater consistency was achieved using the computer-assisted 3D approach for size (intraclass correlation coefficient [ICC], 1.00), neck measurements (ICC, 0.96), and shape quantification (UI; ICC, 0.94). CONCLUSIONS: Computer-assisted 3D morphology analysis can improve accuracy and consistency in measurements compared with manual 2D measurements. It can also more reliably quantify shape irregularity using the UI. Future application of computer-assisted analysis tools could help clinicians standardize morphology evaluations, leading to more consistent IA evaluations.

Feasibility, safety, and changes in systolic blood pressure associated with endovascular revascularization of symptomatic and chronically occluded cervical internal carotid artery using a newly suggested radiographic classification of chronically occluded cervical internal carotid artery: pilot study.

OBJECTIVEThe overall risk of ischemic stroke from a chronically occluded internal carotid artery (COICA) is around 5%-7% per year despite receiving the best available medical therapy. Here, authors propose a radiographic classification of COICA that can be used as a guide to determine the technical success and safety of endovascular recanalization for symptomatic COICA and to assess the changes in systemic blood pressure following successful revascularization.METHODSThe radiographic images of 100 consecutive subjects with COICA were analyzed. A new classification of COICA was proposed based on the morphology, location of occlusion, and presence or absence of reconstitution of the distal ICA. The classification was used to predict successful revascularization in 32 symptomatic COICAs in 31 patients, five of whom were female (5/31 [16.13%]). Patients were included in the study if they had a COICA with ischemic symptoms refractory to medical therapy. Carotid artery occlusion was defined as 100% cross-sectional occlusion of the vessel lumen as documented on CTA or MRA and confirmed by digital subtraction angiography.RESULTSFour types (A-D) of radiographic COICA were identified. Types A and B were more amenable to safe revascularization than types C and D. Recanalization was successful at a rate of 68.75% (22/32 COICAs; type A: 8/8; type B: 8/8; type C: 4/8; type D: 2/8). The perioperative complication rate was 18.75% (6/32; type A: 0/8 [0%]; type B: 1/8 [12.50%]; type C: 3/8 [37.50%], type D: 2/8 [25.00%]). None of these complications led to permanent morbidity or death. Twenty (64.52%) of 31 subjects had improvement in their symptoms at the 2-6 months' follow-up. A statistically significant decrease in systolic blood pressure (SBP) was noted in 17/21 (80.95%) patients who had successful revascularization, which persisted on follow-up (p = 0.0001). The remaining 10 subjects in whom revascularization failed had no significant changes in SBP (p = 0.73).CONCLUSIONSThe pilot study suggested that our proposed classification of COICA may be useful as an adjunctive guide to determine the technical feasibility and safety of revascularization for symptomatic COICA using endovascular techniques. Additionally, successful revascularization may lead to a significant decrease in SBP postprocedure. A Phase 2b trial in larger cohorts to assess the efficacy of endovascular revascularization using our COICA classification is warranted.

Pipeline embolization of posterior circulation aneurysms: a multicenter study of 131 aneurysms.

OBJECTIVE: Flow diversion for posterior circulation aneurysms performed using the Pipeline embolization device (PED) constitutes an increasingly common off-label use for otherwise untreatable aneurysms. The safety and efficacy of this treatment modality has not been assessed in a multicenter study. METHODS: A retrospective review of prospectively maintained databases at 8 academic institutions was performed for the years 2009 to 2016 to identify patients with posterior circulation aneurysms treated with PED placement. RESULTS: A total of 129 consecutive patients underwent 129 procedures to treat 131 aneurysms; 29 dissecting, 53 fusiform, and 49 saccular lesions were included. At a median follow-up of 11 months, complete and near-complete occlusion was recorded in 78.1%. Dissecting aneurysms had the highest occlusion rate and fusiform the lowest. Major complications were most frequent in fusiform aneurysms, whereas minor complications occurred most commonly in saccular aneurysms. In patients with saccular aneurysms, clopidogrel responders had a lower complication rate than did clopidogrel nonresponders. The majority of dissecting aneurysms were treated in the immediate or acute phase following subarachnoid hemorrhage, a circumstance that contributed to the highest mortality rate in those aneurysms. CONCLUSIONS: In the largest series to date, fusiform aneurysms were found to have the lowest occlusion rate and the highest frequency of major complications. Dissecting aneurysms, frequently treated in the setting of subarachnoid hemorrhage, occluded most often and had a low complication rate. Saccular aneurysms were associated with predominantly minor complications, particularly in clopidogrel nonresponders.