Surgical Strategies in the Treatment of Giant Pituitary Adenomas.

BACKGROUND AND OBJECTIVES: The management of giant pituitary adenomas (GPAs) is challenging due to associated endocrinopathies and the close proximity of these tumors to critical structures, such as the optic nerves, structures of the cavernous sinus, and hypothalamus. The objective of this review article was to summarize the current management strategies for giant pituitary adenomas, including the role of open and endoscopic surgical approaches and the role of medical and radiation therapy in conjunction with surgery. METHODS: We conducted a retrospective review of GPAs operated at our institute between January 2010 and March 2023. Surgical approaches, extent of resection, and associated complications were documented. Furthermore, we conducted a thorough literature review to identify relevant studies published in the past decade, which were incorporated along with insights gained from our institutional case series of GPAs to analyze and integrate both the existing knowledge base and our institution's firsthand experience in the management of GPAs. RESULTS: A total of 46 giant pituitary adenomas (GPAs) were operated on, using various surgical approaches. Transsphenoidal approach was used in 25 cases and a staged approach using transsphenoidal and pterional was used in 15 cases. Other approaches included transcortical-transventricular, transcallosal, pterional/orbitozygomatic, and subfrontal approaches. Complications and technical nuances were reported. CONCLUSION: The management of giant pituitary adenomas remains complex, often involving several modalities-open or endoscopic resection, radiosurgery, and medical management of both the tumor and associated endocrinopathies. Surgical resections are often challenging procedures that require careful consideration of several factors, including patient characteristics, tumor location, and size, and the experience and skill of the surgical team.

Femoral access site complications following neurointerventional procedures: economic implications at a single center.

OBJECTIVE: Transfemoral access (TFA) has been the traditional route of arterial access for neurointerventional procedures. Femoral access site complications may occur in 2%-6% of patients. Management of these complications often requires additional diagnostic tests or interventions, each of which may increase the cost of care. The economic impact of a femoral access site complication has not yet been described. The objective of this study was to evaluate the economic consequences of femoral access site complications. METHODS: The authors conducted a retrospective review of patients undergoing neuroendovascular procedures at their institute and identified those who experienced femoral access site complications. The subset of patients experiencing these complications during elective procedures was matched in a 1:2 fashion to a control group undergoing similar procedures and not experiencing an access site complication. RESULTS: Femoral access site complications were identified in 77 patients (4.3%) over a 3-year period. Thirty-four of these complications were considered major, requiring blood transfusion or additional invasive treatment. There was a statistically significant difference in total cost ($39,234.84 vs $23,535.32, p = 0.001), total reimbursement ($35,500.24 vs $24,861.71, p = 0.020) and reimbursement minus cost (-$3734.60 vs $1326.39, p = 0.011) between the complication and control cohorts in elective procedures, respectively. CONCLUSIONS: Although occurring relatively infrequently, femoral artery access site complications increase the cost of care for patients undergoing neurointerventional procedures; how this influences the cost effectiveness of neurointerventional procedures warrants further investigation.

Evolution of Transradial Access for Mechanical Thrombectomy-A Single Center Experience.

BACKGROUND: Transradial access (TRA) recently has gained popularity among neurointerventionalists. However, hesitation to its use for mechanical thrombectomy (MT) remains. OBJECTIVE: To evaluate and describe the evolution of TRA for MT. METHODS: We performed a retrospective analysis of patients undergoing TRA for MT. We performed a chronological ternary analysis to assess the impact of experience. We assessed the impact of a guide catheter designed specifically for TRA. RESULTS: We identified 53 patients who underwent TRA for MT. There was a statistically significant decrease in contrast use (148.9 vs 109.3 vs 115.2 cc), procedure time (62.4 vs 44.7 vs 41.3 minutes), fluoroscopy time (39.2 vs 44.7 vs 41.3 minutes), and puncture-to-recanalization time (40.6 vs 27.3 vs 29.4) over time. There was trend toward improved thrombolysis in cerebral infarction ≥ 2b recanalization rate (72.2% vs 77.8% vs 100%) over time. The introduction of a radial-specific catheter had a statistically significant positive impact on contrast use (133.8 vs 93 cc, P = .043), procedure time (54.2 vs 36.4 minutes, P = .003), fluoroscopy time (33.7 vs 19.8 minutes, P = .004), puncture-to-recanalization time (35.8 vs 25.1 minutes, P = .016), and thrombolysis in cerebral infarction ≥ 2b recanalization rate (71.4% vs 100%, P = .016). CONCLUSION: TRA is a safe and effective route of endovascular access for MT. Experience with this technique improves its efficacy and efficiency. The introduction of a TRA-specific catheter expands the armamentarium of the neurointerventionalist and may facilitate lesion access during MT procedures. Continued development of radial-specific devices may further improve MT outcomes.

Multimodal monitoring to guide neurosurgical intervention in high-grade aneurysmal subarachnoid hemorrhage: illustrative case.

BACKGROUND: Multimodal monitoring to guide medical intervention in high-grade aneurysmal subarachnoid hemorrhage (aSAH) is well described. Multimodal monitoring to guide surgical intervention in high-grade aSAH has been less studied. OBSERVATIONS: Intracranial pressure (ICP), brain lactate to pyruvate ratio (L/P ratio), and brain parenchymal oxygen tension (pO2) were used as surrogates for clinical status in a comatose man after high-grade aSAH. Acute changes in ICP, L/P ratio, and pO2 were used to identify brain injury from both malignant cerebral edema and delayed cerebral ischemia, respectively, and decompressive hemicraniectomy with clot evacuation and intraarterial nimodipine were used to treat these conditions. The patient showed marked improvement in multimodal parameters following each intervention and eventually recovered to a modified Rankin score of 2. LESSONS: In patients with a limited neurological examination due to severe acute brain injury in the setting of aSAH, multimodal monitoring can be used to guide surgical treatment. With prompt, aggressive, maximal medical and surgical interventions, otherwise healthy individuals may retain the capacity for close to full recovery from seemingly catastrophic aSAH.

The Rist radial access system: a multicenter study of 152 patients.

BACKGROUND: Transradial access (TRA) for neurointervention is becoming increasingly popular as experience with the technique grows. Despite reasonable efficacy using femoral catheters off-label, conversion to femoral access occurs in approximately 8.6-10.3% of TRA cases, due to an inability of the catheter to track into the vessel of interest, lack of support, or radial artery spasm. METHODS: This is a multicenter, retrospective case series of patients undergoing neurointerventions using the Rist Radial Access System. We also present our institutional protocol for using the system. RESULTS: 152 patients were included in the cohort. The most common procedure was flow diversion (28.3%). The smallest radial diameter utilized was 1.9 mm, and 44.1% were performed without an intermediate catheter. A majority of cases (96.1%) were completed successfully; 3 (1.9%) required conversion to a different radial catheter, 2 (1.3%) required conversion to femoral access, and 1 (0.7%) was aborted. There was 1 (0.7%) minor access site complication and 4 (2.6%) neurological complications. CONCLUSIONS: The Rist catheter is a safe and effective tool for a wide range of complex neurointerventions, with lower conversion rates than classically reported.

Anatomical Predictors of Transcranial Surgical Access to the Suprasellar Space.

Objective The suprasellar space is a common location for intracranial lesions. The position of the optic chiasm (prefixed vs. postfixed) results in variable sizes of operative corridors and is thus important to identify when choosing a surgical approach to this region. In this study, we aim to identify relationships between suprasellar anatomy and external cranial metrics to guide in preoperative planning. Methods T2-weighted magnetic resonance images (MRIs) from 50 patients (25 males and 25 females) were analyzed. Various intracranial and extracranial metrics were measured. Statistical analysis was performed to determine any associations between metrics. Results Interoptic space (IOS) size correlated with interpupillary distance (IPD; a = 7.3, 95% confidence interval [CI] = 4.5-10.0, R 2 = 0.3708, p = 0.0009). IOS size also correlated with fixation of the optic chiasm, for prefixed chiasms ( n = 7), the mean IOS is 205.14 mm 2 , for normal chiasm position ( n = 33) the mean IOS is 216.94 mm 2 and for postfixed chiasms ( n = 10) the mean IOS is 236.20 mm 2 ( p = 0.002). IPD correlates with optic nerve distance (OND; p = 0.1534). Cranial index does not predict OND, IPD, or IOS. Conclusion This study provides insight into relationships between intracranial structures and extracranial metrics. This is the first study to describe a statistically significant correlation between IPD and IOS. Surgical approach can be guided in part by the size of the IOS and its correlates. Particularly small intraoptic space may guide the surgeon away from a subfrontal approach.

Pre-operative embolization followed by clipping of Cognard type V dural arteriovenous fistula.

This article has been retracted because it describes the use of an investigative agent that has not been approved by the Food and Drug Administration.

Carotid artery stenting in a patient with an anomalous vertebral artery origin from the external carotid artery.

The existence of carotid basilar anastomoses has been well documented embryologically, anatomically, and, in the case of the persistent trigeminal and hypoglossal arteries, angiographically. Conversely, anomalous origins of the vertebral arteries (VA) are not very common with an incidence ranging from 3% to 8%. Multiple variations of the VA origin have been reported in the literature, including arising from the aortic arch, from the common, internal, or external carotid arteries and subclavian branches.1 There are only four cases reported in the literature of VA origin from the external carotid artery.2-5 We report the fifth case in which the anomalous origin was identified during the investigation of an acute ischemic stroke. Video 1 emphasizes the importance of anatomical knowledge prior to endovascular or surgical interventions. It also highlights technical nuances of carotid artery stenting in a patient with anomalous VA origin from the external carotid artery. neurintsurg;13/10/974/V1F1V1Video 1.

Surgical Resection of Clinoidal Meningiomas without Routine Use of Clinoidectomy.

OBJECTIVE: Meningiomas of the anterior clinoid process (ACP) present significant surgical challenges given their anatomic relation to critical neurovascular structures. Routine anterior clinoidectomy is often described as a critical step in the resection of these tumors to reduce recurrence and improve visual outcomes. Anterior clinoidectomy, however, is not without risk and its benefits have not been clearly delineated. We present the outcomes of our series of surgically managed ACP meningiomas in which an anterior clinoidectomy was not routinely employed. METHODS: A retrospective review of all ACP meningiomas operated on between August 1997 and March 2019 was conducted. Patients with a recurrent tumor or with <6 months of follow-up were excluded. Resection was typically carried out via a frontotemporal craniotomy followed by intradural removal of the tumor. Anterior clinoidectomy was only performed if hyperostosis of the ACP caused mass effect on the optic nerve. RESULTS: Twenty-nine patients were included in this study. Anterior clinoidectomy was performed in 3 patients (10.3%). Gross total resection was achieved in 22 patients (75.9%). Of the 21 patients (72.4%) who presented with visual deficits, vision improved in 18 patients (85.7%) and worsened in 2 (9.5%). Tumor recurrence occurred in 5 patients (17.2%) at a mean follow-up of 64.9 months. Perioperative morbidity was 10.3%. Permanent morbidity and mortality were 6.9% (vision deterioration) and 0%, respectively. CONCLUSIONS: Resection of ACP meningiomas without routine anterior clinoidectomy minimizes potential risk while achieving gross total resection, recurrence, and visual improvement rates comparable with those in previously reported series.

Transition to Transradial Access for Mechanical Thrombectomy-Lessons Learned and Comparison to Transfemoral Access in a Single-Center Case Series.

BACKGROUND: Trends in mechanical thrombectomy have emphasized larger bore aspiration catheters that may be difficult to deploy from a radial access point due to size constraints or need to obtain sheathless access. As such, many neurointerventionists are reticent to attempt thrombectomy through transradial access (TRA) for fear of worse outcomes. OBJECTIVE: To explore whether mechanical thrombectomy could be achieved safely and effectively through the transradial route. METHODS: We retrospectively analyzed the records of patients undergoing mechanical thrombectomy at our academic institute between January 2018 and January 2019, which corresponded to a time when we began to transition to TRA for neurointerventions, including mechanical thrombectomy. We compared the procedural details and clinical outcomes of patients undergoing mechanical thrombectomy using TRA with those using transfemoral access (TFA). RESULTS: During the study period, 44 patients underwent mechanical thrombectomy with TRA and 129 with TFA. There was no statistically significant difference in door-to-access time, door-to-reperfusion time, or first-pass recanalization rate. There was no significant difference in modified Rankin Scale (mRS) score at discharge, mRS score at last follow-up, or length of stay. There were 7 access-site complications in the TFA group and none in the TRA group. One patient in the TRA group required crossover to TFA. CONCLUSION: Mechanical thrombectomy can be performed safely and effectively from a TRA site without compromising recanalization times or rates. TRA has superior access-site complication profiles compared to TFA.

Influence of thrombectomy volume on non-physician staff burnout and attrition in neurointerventional teams.

BACKGROUND: Burnout takes a heavy toll on healthcare providers. We sought to assess the prevalence and risk factors for burnout among neurointerventional (NI) non-physician procedural staff (nurses and technologists) given increasing thrombectomy demands. METHODS: A 41-question online survey containing questions including the Maslach Burnout Inventory-Human Services Survey for Medical Personnel was distributed to NI nurses and radiology technologists at 20 US endovascular capable stroke centers. RESULTS: 244 responses were received (64% response rate). Median (IQR) composite scores for emotional exhaustion were 25 (15-35), depersonalization 6 (2-11), and personal accomplishment 39 (35-43). Fifty-one percent of respondents met established criteria for burnout. There was no significant relationship between hospital thrombectomy volume, call frequency, call cases covered, or length of commute. On multiple logistic regression analysis, feeling under-appreciated by hospital leadership (OR 4.1; P<0.001) and working with difficult/unpleasant physicians (OR 1.2; P=0.05) were strongly associated with burnout. At participating centers, nurse and technologist attrition was 25% over the previous year. Over 50% of respondents indicated they had strongly considered leaving their position over the last 2 years. CONCLUSIONS: This survey of US NI non-physician procedural staff demonstrates a self-reported burnout prevalence of 51%. This was driven more by interaction with leadership and physician staff than by thrombectomy procedural volume and stroke call. Attrition among NI non-physician procedural staff is high.

Trends in United States neurosurgery residency education and training over the last decade (2009-2019).

OBJECTIVE: Postgraduate training in medicine has been under scrutiny in the last 10 years, with a focus on improving residents' education. The aim of this study was to quantify trends in neurosurgery residency (NSR) training and education over the last 10 years. METHODS: The authors assessed Accreditation Council for Graduate Medical Education (ACGME), National Resident Matching Program, and American Board of Neurological Surgeons records and searched PubMed to collate 2009-2019 data. Analyzed trends included residents' demographic data, programs' characteristics, graduation and attrition rates, match data, resident case logs, and qualitative educational curriculum changes. RESULTS: Significant increases in residents' demographic data (p < 0.05) included the number of female residents (from 12.7% to 17.6%) and the absolute number of residents (from 1112 to 1462). Age (mean 28.8 years), ethnicity, and number of residents per program (mean 13 residents per program) were unchanged. There were 16 new ACGME NSR programs, with currently 115 programs nationwide. The number of applicants per year (324 applicants per year) and the matching rate (mean 64%) remained stable. The mean attrition rate of 2.6% (range 2%-4%) was higher than the mean 2.1% ACGME attrition rate, a rate that decreased from 3% in 2009 to 1.6% in 2019. Education curriculum changes aimed at the standardization of training across the US included residents' boot camp (2009), the Milestones project (2012), and mandatory 7-year training initiated in 2013. An increase in endovascular, functional, trauma, and spine resident caseload was noted. The number of yearly publications about US NSR education has significantly increased (p < 0.05). CONCLUSIONS: NSR education has received greater attention over the last decade in the US. Standardization of training has been implemented. A steady number of students remain interested in neurosurgery, with an increased number of women entering the field. Attention to wellness, in addition to high-quality education, should be further assessed as a factor to improve the overall NSR training and retention rate.

Transradial approach for neurointerventions: a systematic review of the literature.

BACKGROUND: Despite the recent increase in the number of publications on diagnostic cerebral angiograms using transradial access (TRA), there have been relatively few regarding TRA for neurointerventional cases. Questions of feasibility and safety may still exist among physicians considering TRA for neurointerventional procedures. METHODS: A systematic literature review was performed following PRISMA guidelines. Three online databases (MedLine via PubMed, Scopus and Embase) were searched for articles published between January 2000 and December 2019. Search terms included "Transradial access", "Radial Access", "Radial artery" AND "Neurointerventions". The reference lists of selected articles and pertinent available non-systematic analysis were reviewed for other potential citations. Primary outcomes measured were access site complications and crossover rates. RESULTS: Twenty-one studies (n=1342 patients) were included in this review. Two of the studies were prospective while the remaining 19 were retrospective. Six studies (n=616 patients) included TRA carotid stenting only. The rest of the studies included treatment for cerebral aneurysms (n=423), mechanical thrombectomy (n=127), tumor embolization (n=22), and other indications (n=154) such as angioplasty and stenting for vertebrobasilar stenosis, balloon test occlusion, embolization of dural arteriovenous fistula and arteriovenous malformation, chemotherapeutic drug delivery, intra-arterial thrombolysis, and arterial access during a venous stenting procedure. Two (0.15%) major complications and 37 (2.75%) minor complications were reported. Sixty-four (4.77%) patients crossed over to transfemoral access for completion of the procedure. Seven (0.52%) patients crossed over due to access failure and 57 (4.24%) patients crossed over to TFA due to inability to cannulate the target vessel. CONCLUSION: This systematic review demonstrates that TRA has a relatively low rate of access site complications and crossovers. With increasing familiarity, development of TRA-specific neuroendovascular devices, and the continued reports of its success in the literature, TRA is expected to become more widely used by neurointerventionalists.

Make Clipping Great Again: Microsurgery for Cerebral Aneurysms by Dual-Trained Neurosurgeons.

OBJECTIVE: Despite an increasing focus on endovascular treatment of cerebral aneurysms, microsurgical clipping remains an integral part of management. We evaluated the safety and effectiveness of microsurgical clipping performed by dual-trained neurosurgeons at our institute, which has adopted an endovascular first approach. METHODS: We retrospectively reviewed clinical and radiographic data of 412 aneurysms in 375 patients treated with microsurgical clipping. Univariate and multivariate analyses were performed to identify predictive outcome factors. We defined favorable outcome as a modified Rankin Scale (mRS) score of 0-2 at last clinical follow-up; unfavorable outcome was an mRS score of 3-6. We compared outcomes in our series with those of seminal aneurysm clipping series. RESULTS: Clipping of 330 of 351 unruptured aneurysms (94.01%) was associated with favorable outcome during the follow-up period (mean, 26.5 months). On univariate analysis, older patient age, intraoperative rupture, and higher baseline mRS scores were associated with unfavorable outcome in the unruptured cohort. On multivariate analysis, older age, higher baseline mRS scores, and posterior circulation aneurysm location were predictive of unfavorable outcome. Clipping of 46 of 61 ruptured aneurysms (75.4%) was associated with favorable outcome during the follow-up period (mean, 23.1 months). On univariate analysis, left-sided aneurysms, intraoperative rupture, and large aneurysm size were associated with unfavorable outcome in the ruptured cohort. On multivariate analysis, female sex was predictive of unfavorable outcome. CONCLUSIONS: Our ruptured and unruptured cohort results compared favorably with those in seminal series. Treatment by neurosurgeons adept at both endovascular and microsurgical techniques may improve clinical outcomes.

Single-center experience of using high definition (Hi-Def) imaging during neurointervention treatment of intracranial aneurysms using flow diverters.

BACKGROUND: A new dual resolution imaging x-ray detector system (Canon Medical Systems Corporation, Tochigi, Japan) has a standard resolution 194 µm pixel conventional flat-panel detector (FPD) mode and a high-resolution 76 µm high-definition (Hi-Def) mode in a single unit. The Hi-Def mode enhances the visualization of the intravascular devices. OBJECTIVE: We report the clinical experience and physician evaluation of this new detector system with Hi-Def mode for the treatment of intracranial aneurysms using a Pipeline embolization device (PED). METHODS: During intervention at our institute, under large field of view (FOV) regular resolution FPD mode imaging, the catheter systems and devices were first guided to the proximity of the treatment area. Final placement and deployment of the PED was performed under Hi-Def mode guidance. A post-procedure 9-question physician survey was conducted to qualitatively assess the impact of Hi-Def mode visualization on physicians' intraoperative decision-making. One-sample t-test was performed on the responses from the survey. Dose values reported by the x-ray unit were also recorded. RESULTS: Twenty-five cases were included in our study. The survey results indicated that, for each of the nine questions, the physicians in all cases indicated that the Hi-Def mode improved visualization compared with the FPD mode. For the 25 cases, the mean cumulative entrance air kerma was 2.35 Gy, the mean dose area product (DAP) was 173.71 Gy.cm2, and the mean x-ray exposure time was 39.30 min. CONCLUSIONS: The Hi-Def mode improves visualization of flow diverters and may help in achieving more accurate placement and deployment of devices.

"Strokenomics": bending the cost curve in stroke care.

OBJECTIVE: The mortality rates for stroke are decreasing, yet it remains a leading cause of disability and the principal neurological diagnosis in patients discharged to nursing homes. The societal and economic burdens of stroke are substantial, with the total annual health care costs of stroke expected to reach $240.7 billion by 2030. Mechanical thrombectomy has been shown to improve functional outcomes compared to medical therapy alone. Despite an incremental cost of $10,840 compared to medical therapy, the improvement in functional outcomes and decreased disability have contributed to the cost-effectiveness of the procedure. In this study the authors describe a physician-led device bundle purchase program implemented for the delivery of stroke care. METHODS: The authors retrospectively reviewed the clinical and radiographic data and device-associated charges of 45 consecutive patients in whom a virtual "stroke bundle" model was used to purchase mechanical thrombectomy devices. RESULTS: Use of the stroke bundle to purchase mechanical thrombectomy devices resulted in an average savings per case of $2900.93. Compared to the traditional model of charging for devices à la carte, this represented an average savings of 25.2% per case. The total amount of savings for these initial 45 cases was $130,542.00. Thrombolysis in Cerebral Infarction scale grade 2b or 3 recanalization occurred in 38 patients (84.4%) using these devices. CONCLUSIONS: Purchasing devices through a bundled model resulted in substantial cost savings while maintaining the therapeutic efficacy of the procedure, further pushing the already beneficial long-term cost-benefit curve in favor of thrombectomy.

Dual Microwire Rail Technique to Advance a Microcatheter Past the Ostium of a Dissecting Carotid Artery Aneurysm for Flow Diverter Deployment: 2-Dimensional Operative Video.

Flow diversion using a Pipeline embolization device (PED; Medtronic, Dublin, Ireland) is an effective therapy for treating cavernous aneurysms. Currently, flow diverters require a 0.027-inch microcatheter for deployment. To navigate across these aneurysms, a 0.014-inch microwire is used, which often does not offer a sturdy enough rail to advance a 0.027-inch microcatheter past dissecting artery aneurysm ostia. We present a patient with a right cavernous dissecting carotid artery aneurysm. A step off between the 0.027-inch VIA microcatheter (MicroVention Terumo, Tustin, California) and 0.014-inch Synchro 2 microwire (Stryker Neurovascular, Fremont, California) resulted in difficulty with navigation of the microcatheter across the dissected portion of the aneurysm. A dual microwire rail technique involving two 0.014-inch Synchro 2 microwires was used to advance the VIA microcatheter past the dissecting artery aneurysm ostia for PED deployment. The introduction of the second microwire eliminated the step off between the microwire and microcatheter, providing a stronger rail and easier navigation of the microcatheter, without aggressive pushing. Postembolization runs showed optimal wall apposition and contrast stasis within the aneurysm, with successful flow diversion of the aneurysm. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary.

Is Contrast Stasis After Pipeline Embolization Device Deployment Associated with Higher Aneurysm Occlusion Rates?

OBJECTIVE: To assess the association of degree of contrast stasis in intracranial aneurysms (IAs) immediately after Pipeline embolization device (PED; Medtronic, Dublin, Ireland) deployment with 6- and 12-month angiographic occlusion rates. METHODS: This retrospective cohort study included consecutive patients undergoing PED deployment for saccular IA treatment at a large-volume cerebrovascular center over a 4-year 9-month period. Angiographic images obtained immediately after PED deployment were graded according to amount of intra-aneurysmal contrast flow during the late venous phase: 0 = no stasis; 1 = <50% contrast stasis; 2 = 50%-75% stasis; and 3 = >75%-99% stasis. Follow-up occlusion rates were determined by digital subtraction angiography, computed tomographic angiography, or magnetic resonance angiography. RESULTS: The study included 119 patients in whom 182 PEDs were deployed to treat 141 aneurysms. A single PED was deployed in 105 (74.5%) aneurysms. The internal carotid artery was the commonest aneurysm site (119 [85%]). Fifty-two (36.9%) aneurysms were grade 0; 33 (23.4%) were grade 1; 46 (32.6%) were grade 2; and 10 (7.1%) were grade 3 immediately post-treatment. A 6-month follow-up angiogram available for 101 aneurysms showed complete occlusion (no flow into the aneurysm) in 74 (73.3%) aneurysms. A 12-month follow-up study available for 132 aneurysms showed complete occlusion in 79.5%. At last follow-up, occlusion rates were not significantly different for different contrast stasis grades (P = 0.60). Mean angiographic follow up for all IAs was 23v±v17.7 months. IA size, sex, age, and smoking were not significant predictors of occlusion. CONCLUSIONS: The degree of aneurysm contrast stasis immediately after PED deployment is not statistically associated with 6- and 12-month angiographic occlusion rates.