Clot composition and recanalization outcomes in mechanical thrombectomy

BACKGROUND

Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes.

METHODS

Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin-eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of first-pass effect (FPE, modified Thrombolysis in Cerebral Infarction 2c/3) and the number of passes.

RESULTS

A total of 1430 patients of mean±SD age 68.4±13.5 years (median (IQR) baseline National Institutes of Health Stroke Scale score 17.2 (10.5-23), IV-tPA use 36%, stent-retrievers (SR) 27%, contact aspiration (CA) 27%, combined SR+CA 43%) were included. The median (IQR) number of passes was 1 (1-2). FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for red blood cell (RBC)-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes than RBC-rich and mixed clots (median 2 and 1.5 vs 1, respectively; P=0.02). CA showed a trend towards a higher number of passes with fibrin-rich clots (2 vs 1; P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots.

CONCLUSIONS

Despite the lack of correlation between clot histology and FPE, our study adds to the growing evidence supporting the notion that clot composition influences recanalization treatment strategy outcomes.

Clinical and radiological features of parasagittal dural arteriovenous fistulas: a report of 8 cases from a single institution

OBJECTIVE

Dural arteriovenous fistulas (dAVFs) of the superior sagittal sinus (SSS) are uncommon and represent 5%-12% of all intracranial dAVFs. SSS dAVFs can be divided into two main subtypes. The first type involves direct arterialization of the SSS, whereas the second type consists of a parasagittal arteriovenous shunt draining into a cortical vein directly lateral to the SSS and has retrograde cortical venous drainage with only secondary involvement of the SSS. Descriptions of the latter type of SSS dAVF are limited. As such, the authors present a consecutive case series of parasagittal SSS dAVFs from their institution. They detail clinical presentation, treatment strategies, and clinical and radiographic outcomes.

METHODS

The authors retrospectively reviewed a prospectively collected database of dAVFs that were treated between 2017 and 2023. All dAVFs characterized by an arterialized parasagittal vein directly lateral to the SSS were included in this study. Baseline demographic, clinical, radiological, treatment, and outcome-specific variables of interest were abstracted.

RESULTS

One hundred fifty-four dAVFs were seen at the authors' institution over the 6-year period of interest. Eight (5.2%) were parasagittal dAVFs. At initial diagnostic imaging, 7 were Cognard grade III and 1 was grade IV. All patients initially underwent embolization of their dAVF. Three patients did not have complete obliteration of their dAVF after the first embolization. One patient underwent further treatment with repeat embolization, and 1 underwent microsurgical disconnection-both resulted in complete occlusion of the dAVF. Seven dAVFs were obliterated at final follow-up and 1 remained patent as the patient refused further treatment despite angiographic progression of dAVF. All symptomatic patients had resolution of their symptoms, and the average length of follow-up was 16.8 months.

CONCLUSIONS

Treatment of parasagittal dAVFs consists of occluding the proximal portion of the parasagittal arterialized draining vein. Endovascular therapy with liquid embolic agents is usually the first line of treatment. Surgical ligation is a valid option if the fistula cannot be successfully obliterated with embolization. Symptoms related to the SSS dAVF resolve after their obliteration.

Angiographic cross-filling between inferior petrosal sinuses and alteration of adrenocorticotropic hormone sampling results for tumor localization in Cushing disease

OBJECTIVE

Inferior petrosal sinus (IPS) sampling (IPSS) is a diagnostic procedure used to guide diagnostic localization of imaging-negative adrenocorticotropic hormone (ACTH)-secreting pituitary microadenomas. However, the efficacy of IPSS has been suboptimal at accurately lateralizing the adenoma, reducing surgical cure rates and leading to unintended pituitary dysfunction due to the added exploration. One rationale for the occasional imprecision is the existence of additional petrosal sinus collateral channels that connect the IPS bilaterally, which may lead to false localization results during sampling. The aim of this study was to explore a potential connection between normal anatomical variation in the angioarchitecture of the IPSs and the ACTH results obtained in subsequent IPSS tests.

METHODS

A retrospective review was performed on all cases between 1998 and 2013 involving patients at a single institution who underwent IPSS for radiographically equivocal pituitary microadenomas. Cases were reviewed for tumor laterality noted on either operative or pathology reports, as well as the presence of angiographic evidence of cross-filling between the sinuses. In addition, ACTH levels from the right and left IPSs were documented at baseline and at 2, 5, and 10 minutes after corticotropin-releasing hormone (CRH) administration. A ratio of the change in ACTH levels measured at the time of maximal response (10 minutes) versus the levels measured at the initial response (2 minutes) was computed for each patient and compared between patients by their angiographic cross-filling status.

RESULTS

There were 41 patients with a histopathologically confirmed right- or left-sided ACTH-secreting pituitary microadenoma who underwent preoperative IPSS. Among these patients, 28 (68%) showed angiographic evidence of cross-filling between the IPSs, and 13 showed no cross-filling. On average, ACTH levels increased by a factor of 3.91 ± 0.77 in the contralateral IPS in patients with angiographic cross-filling, compared with a factor increase of only 1.80 ± 0.27 in patients without cross-filling (p = 0.014). In comparison, ACTH levels increased by a factor of 2.01 ± 0.57 in the ipsilateral IPS in patients with cross-filling, and by 8.78 ± 7.30 in those without cross-filling (p = 0.373).

CONCLUSIONS

The presence of angiographic cross-filling, suggestive of a greater degree of vascular channel networking between the right and left IPS, is a significant factor influencing the measured rates of change of ACTH in IPSS and may impact the specificity of this test to accurately determine microadenoma laterality in the preoperative setting.

Zilver stent versus Carotid Wallstent for endovascular treatment of idiopathic intracranial hypertension

BACKGROUND

Venous sinus stenting (VSS) is a promising treatment option for medically refractory idiopathic intracranial hypertension (IIH). There are no published studies comparing the performance of different types of stents employed in VSS procedures. In this study we aimed to compare the safety and efficacy outcomes of the Zilver 518 (Cook Medical, Bloomington, Indiana, USA) and the Carotid Wallstent (Boston Scientific, Marlborough, Massachusetts, USA) devices.

METHODS

Records of patients with IIH who underwent VSS between January 2015 and February 2022 at a single referral center were retrospectively reviewed. Patients treated with the Zilver stent or Carotid Wallstent were included in the study. Stent model and size data, pre- and post-treatment pressure gradients, technical and safety outcomes, and pre- and post- stenting papilledema, headache, and tinnitus severity were collected. The χ2 and Fisher-Freeman-Halton tests were used for categorical data and the Student's t-test and Mann-Whitney U test were employed to examine the differences in non-categorical variables.

RESULTS

A total of 81 procedures (28 (34.5%) with the Zilver stent and 53 (65.5%) with the Carotid Wallstent) were performed in 76 patients. The mean procedure time was significantly shorter with the Zilver stent (22.56±10.2 vs 33.9±15 min, p=0.001). The papilledema improvement and resolution rates did not significantly differ between groups (94.7% vs 94.5%, p>0.99 for improvement; 78.9% vs 67.5%, p=0.37 for resolution). The tinnitus improvement and resolution rates in the Zilver stent group were significantly higher than those of the Carotid Wallstent group (100% vs 78.9%, p=0.041; 90% vs 63.1%, p=0.03, respectively). Additionally, the Zilver stent provided a significantly higher rate of headache resolution and improvement than the Carotid Wallstent (84.6% vs 27.6%, p=0.001 for resolution; 92.3% vs 72.3%, p=0.043 for improvement). One patient from the Carotid Wallstent group underwent re-stenting due to in-stent stenosis and refractory papilledema. No significant in-stent stenosis was observed in the Zilver stent group.

CONCLUSION

Stent choice may affect VSS outcomes. The Zilver stent provided better clinical outcomes than the Carotid Wallstent, with significantly shorter procedure times. Larger studies are needed to determine the efficacy of available venous stents for IIH.

WEB (Woven EndoBridge) device for intracranial aneurysm treatment: technical, radiological, and clinical findings in a consecutive North American cohort

BACKGROUND

Utilization of Woven EndoBridge (WEB) for treatment of intracranial aneurysms has increased due to increasing operator experience. We aimed to report our contemporary series of a North American center with the WEB, examining factors associated with occlusion rates.

METHOD

Consecutive patients (2019-2022) with intracranial aneurysms treated with WEB device were included. Through a univariate and multivariate analysis, independent predictors of adequate occlusion (RR1/RR2) were examined. Procedural and clinical results were reported.

RESULTS

A total of 104 consecutive aneurysms/patients (25 men/79 women; median age, 63 years, IQR: 55-71) were treated with single-layer WEB-SL in our institution. Seventeen patients (16%) had a ruptured aneurysm. The median aneurysm dome size was 5.5 mm (IQR = 4.5-6.5), and the most common locations were AcomA (36/104 = 34.6%), MCA bifurcation (29/104 = 27.9%), and BT (22/104 = 21.2%). The rate of technical failure was 0.9%. The median intervention time was 32 min (IQR = 25-43). Overall, 8 (7.6%) cases needed additional interventions: 4 (3.8%) additional stenting, 3 cases (3.8%) of intravenous tirofiban infusion (because of the excessive WEB protrusion), and one case (0.9%) of additional coiling (need to complete the neck occlusion). At 12-month follow-up, 67 patients were available showing 59/67 (88%) and 6/67 (9%) of complete occlusion and neck remnant, respectively on dual-energy CTA. There were no cases necessitating retreatment. Ruptured presentation (OR = 0.09, 95% CI = 0.008-0.9, p = .024), undersized WEB (OR = 15, 95% CI = 1.2-50, p = .006), WEB shape change (OR = 0.07, 95% CI = 0.001-0.6, p = .05), aneurysm neck diameter (OR = 0.4, 95% CI = 0.2-0.9, p = .05), and angle between the parent artery and the aneurysm dome (OR = 0.2, 95% CI = 0.01-0.8, p = .008) were significantly associated with occlusion status (RR1-2) at follow-up. However, in the multivariate logistic regression, these factors did not reach the statistical significance. The overall rate of morbidity was 0.9%.

CONCLUSIONS

Our contemporary North American experience on consecutive intracranial aneurysms treated with WEB confirms the medium-term efficacy of this strategy, with low procedural time and morbidity. Further research is needed to demonstrate long-term occlusion rates.

Long-term outcomes following pipeline embolization of unruptured aneurysms

BACKGROUND

Flow diversion using the pipeline embolization device (PED) for unruptured aneurysms is associated with high occlusion and low morbidity and mortality. However, most reports have limited follow-up of 1-2 years. Therefore, we sought to report our outcomes after PED for unruptured aneurysms in patients with at least 5-years of follow-up.

METHODS

Review of patients undergoing PED for unruptured aneurysms from 2009 to 2016.

RESULTS

Overall, 135 patients with 138 aneurysms were included for analysis. Seventy-eight percent of aneurysms (n=107) over a median radiographic follow-up of 5.0 years underwent complete occlusion. Among aneurysms with at least 5-years of radiographic follow-up (n=71), 79% (n=56) achieved complete obliteration. No aneurysm recanalized after radiographic obliteration. Furthermore, over a median clinical follow-up period of 4.9 years, 84% of patients (n=115) self-reported mRS scores between 0 and 2. For patients with at least 5-years of clinical follow-up, 88% (n=61) reported mRS between 0 and 2. In total, 3% (n=4) of patients experienced a major, non-fatal neurologic complication related to the PED, 5% (n=7) of patients experienced a minor neurologic complication related to PED placement, and 2% (n=3) died from either delayed aneurysm rupture, delayed ipsilateral hemorrhage after PED placement, or delayed (9 months after treatment) neural compression after progressive thrombosis of a PED-treated dolichoectactic vertebrobasilar aneurysm.

CONCLUSIONS

Treatment of unruptured aneurysms with the PED is associated with high rates of long-term angiographic occlusion and low, albeit clinically important, rates of major neurologic morbidity and mortality. Thus, flow diversion via PED placement is safe, effective, and durable.

Abstract 99: Clot Composition And Reperfusion Outcomes In 1430 Mechanical Thrombectomy Patients: Analysis Of The Stroke Thromboembolism Registry Of Imaging And Pathology

Background: Understanding clot composition may allow for better technical planning and improved outcomes in mechanical thrombectomy (MT). We sought to correlate clot composition with reperfusion outcomes in MT.

Methods: Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin and eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of First-Pass Effect (mTICI2c/3, FPE) and the number of device passes.

Results: A total of 1430 patients (mean age, 68.4±13.5years; median [IQR] baseline NIHSS,17.2 [10.5-23]; IV-tPA use, 36%; Stent-Retrievers [SR], 27%; Contact Aspiration [CA], 27%; Combined SR + CA, 43%) were included. The median [IQR] number of passes was 1 [1-2]. FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for RBC-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes compared to RBC-rich and mixed clots (median, 2 and 1.5 vs.1, respectively, P=0.02). CA displayed a trend towards a higher number of passes with fibrin-rich clots (2 vs.1, P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots.

Conclusion: Despite the lack of correlation between clot histology and FPE in the overall population, our study adds to the growing body of evidence supporting the notion that clot composition influences reperfusion treatment strategy outcomes. Additional studies are needed.

Quantification of clot spatial heterogeneity and its impact on thrombectomy

BACKGROUND

Compositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis.

METHODS

We collected and did histology on clots retrieved by mechanical thrombectomy from 157 stroke cases (107 achieved first-pass effect (FPE) and 50 did not). Using an in-house algorithm, the scanned images were divided into grids (with sizes of 0.2, 0.3, 0.4, 0.5, and 0.6 mm) and the extent of non-uniformity of RBC distribution was computed using the proposed spatial heterogeneity index (SHI). Finally, we validated the clinical significance of clot heterogeneity using the Mann-Whitney test and an artificial neural network (ANN) model.

RESULTS

For cases with FPE, SHI values were smaller (0.033 vs 0.039 for grid size of 0.4 mm, P=0.028) compared with those without. In comparison, the clot composition was not statistically different between those two groups. From the ANN model, clot heterogeneity was the most important factor, followed by fibrin content, thrombectomy techniques, red blood cell content, clot area, platelet content, etiology, and admission of intravenous tissue plasminogen activator (IV-tPA). No statistical difference of clot heterogeneity was found for different etiologies, thrombectomy techniques, and IV-tPA administration.

CONCLUSIONS

Clot heterogeneity can affect the clot response to thrombectomy devices and is associated with lower FPE. SHI can be a useful metric to quantify clot heterogeneity.

Contemporary Surgical Management of Juvenile Nasopharyngeal Angiofibroma

Objectives Juvenile nasopharyngeal angiofibromas (JNAs) are uncommon tumors with an evolving treatment paradigm. The objective of this study was to compare our prior experience reported in 2005 with our most contemporary series to compare practice improvements and the impact of expanded endonasal procedures.

Design Retrospective review comparing a contemporary 22 patients with JNA who underwent surgical management between 2005 and 2019, compared with a historical cohort of 65 patients from the same center.

Results The most common presenting symptom was epistaxis (68%). The median maximum tumor diameter was 4.4 cm. All patients underwent preoperative embolization. An endoscopic endonasal approach (EEA) was used in 18 patients (82%), compared with 9% in the series prior to 2005. Gross total resection was achieved in all patients. The median estimated blood loss was 175 and 350 mL for EEA and open (transfacial) cases, respectively. Only two patients (9%) required a blood transfusion compared with 52% on the previous series. The median follow-up was 19 months. The overall recurrence rate was 9% in this series and 24% in the previous series. No patient required radiation therapy in follow-up compared with 3% in our historical cohort.

Conclusion There have been significant changes regarding the management of patients with JNA compared with the previous Mayo Clinic experience. The EEA has become the preferred route over the transfacial approaches to treat JNA in selected patients who do not have intracranial extension. Preoperative embolization has aided in reducing the postoperative transfusion rates.

Correlation of von Willebrand factor and platelets with acute ischemic stroke etiology and revascularization outcome: an immunohistochemical study

BACKGROUND

Platelets and von Willebrand factor (vWF) are key components of acute ischemic stroke (AIS) emboli. We aimed to investigate the CD42b (platelets)/vWF expression, its association with stroke etiology and the impact these components may have on the clinical/procedural parameters.

METHODS

CD42b/vWF immunostaining was performed on 288 emboli collected as part of the multicenter STRIP Registry. CD42b/VWF expression and distribution were evaluated. Student's t-test and χ² test were performed as appropriate.

RESULTS

The mean CD42b and VWF content in clots was 44.3% and 21.9%, respectively. There was a positive correlation between platelets and vWF (r=0.64, p<0.001**). We found a significantly higher vWF level in the other determined etiology (p=0.016*) and cryptogenic (p=0.049*) groups compared with cardioembolic etiology. No significant difference in CD42b content was found across the etiology subtypes. CD42b/vWF patterns were significantly associated with stroke etiology (p=0.006*). The peripheral pattern was predominant in atherosclerotic clots (36.4%) while the clustering (patchy) pattern was significantly associated with cardioembolic and cryptogenic origin (66.7% and 49.8%, respectively). The clots corresponding to other determined etiology showed mainly a diffuse pattern (28.1%). Two types of platelets were distinguished within the CD42b-positive clusters in all emboli: vWF-positive platelets were observed at the center, surrounded by vWF-negative platelets. Thrombolysis correlated with a high platelet content (p=0.03*). vWF-poor and peripheral CD42b/vWF pattern correlated with first pass effect (p=0.03* and p=0.04*, respectively).

CONCLUSIONS

The vWF level and CD42b/vWF distribution pattern in emboli were correlated with AIS etiology and revascularization outcome. Platelet content was associated with response to thrombolysis.

Human "live cadaver" neurovascular model for proximal and distal mechanical thrombectomy in stroke

BACKGROUND

Preclinical testing platforms that accurately replicate complex human cerebral vasculature are critical to advance neurointerventional knowledge, tools, and techniques. Here, we introduced and validated a human "live cadaveric" head-and-neck neurovascular model optimized for proximal and distal vascular occlusion and recanalization techniques.

METHODS

Human cadaveric head-and-neck specimens were cannulated bilaterally in the jugular veins, carotid, and vertebral arteries. Specimens were then coupled with modular glass models of the aorta and extracranial carotid arteries, as well as radial and femoral access ports. Intracranial physiological flow was simulated using a flow-delivery system and blood-mimicking fluid. Baseline anatomy, histological, and mechanical properties of cerebral arteries were compared with those of fresh specimens. Radiopaque clot analogs were embolized to replicate proximal and distal arterial occlusions, followed by thrombectomy. Experienced interventionalists scored the model on different aspects.

RESULTS

Compared with counterpart fresh human arteries, formalin-fixed arteries showed similar mechanical properties, including maximum stretch, increased tensile strength/stiffness, and friction coefficients were also not significantly different. On histology, minimal endothelial damage was noted in arteries after 3 months of light fixation, otherwise the arterial wall maintained the structural integrity. Contrast angiographies showed no micro- or macro-vasculature obstruction. Proximal and distal occlusions created within the middle cerebral arteries were consistently obtained and successfully recanalized. Additionally, interventionists scored the model highly realistic, indicating great similarity to patients' vasculature.

CONCLUSIONS

The human "live cadaveric" neurovascular model accurately replicates the anatomy, mechanics, and hemodynamics of cerebral vasculature and allows the performance of neurointerventional procedures equivalent to those done in patients.

Histological composition of retrieved emboli in acute ischemic stroke is independent of pre-thrombectomy alteplase use

BACKGROUND AND PURPOSE

Given recent evidence suggesting the clot composition may be associated with revascularization outcomes and stroke etiology, clot composition research has been a topic of growing interest. It is currently unclear what effect, if any, pre-thrombectomy thrombolysis has on clot composition. Understanding this association is important as it is a potential confounding variable in clot composition research. We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients who did and did not receive pre-treatment tPA to study the effect of tPA on clot composition.

MATERIALS AND METHODS

Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using Martius Scarlett Blue (MSB) staining and area of the clot was also measured on the gross photos. Student's t test was used for continuous variables and chi-squared test for categorical variables.

RESULTS

A total of 1430 patients were included in this study. Mean age was 68.4±13.5 years. Overall rate of TICI 2c/3 was 67%. A total of 517 patients received tPA (36%) and 913 patients did not (64%). Mean RBC density for the tPA group was 42.97±22.62% compared to 42.80±23.18% for the non-tPA group (P=0.89). Mean WBC density for the tPA group was 3.74±2.60% compared to 3.42±2.21% for the non-tPA group (P=0.012). Mean fibrin density for the tPA group was 26.52±15.81% compared to 26.53±15.34% for the non-tPA group (P=0.98). Mean platelet density for the tPA group was 26.22±18.60% compared to 26.55±19.47% for the non-tPA group (P=0.75). tPA group also had significantly smaller clot area compared to non-tPA group.

CONCLUSIONS

Our study 1430 retrieved emboli and ischemic stroke patients shows no interaction between tPA administration and clot composition. These findings suggest that tPA does not result in any histological changes in clot composition.

Anatomy of Spinal Venous Drainage for the Neurointerventionalist: From Puncture Site to Intervertebral Foramen

CSF-venous fistula is a relatively novel entity that is increasingly being recognized as a cause for spontaneous intracranial hypotension. Recently, our group published the first series of transvenous embolization of CSF-venous fistulas in this journal. Having now performed the procedure in 60 patients, we have garnered increasing familiarity with the anatomy and how to navigate our way through the venous system to any intervertebral foramen in the cervical, thoracic, and lumbar spine. The first part of this review summarizes the organization of spinal venous drainage as described in classic anatomy and interventional radiology texts, the same works that we studied when attempting our first cases. In the second part, we draw mostly on our own experience to provide a practical roadmap from the puncture site to the foramen. On the basis of these 2 parts, we hope this article will serve to collate the relevant anatomic knowledge and give confidence to colleagues who wish to embark on transvenous spinal procedures.

Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy

Background

Several animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.

Objective

To investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.

Methods

As part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).

Results

MT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.

Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1–4] vs 1 [1–3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.

Conclusions

Histological markers of VWI were present in 12% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.

Clinical and Imaging Characteristics of Spinal Dural Arteriovenous Fistulas and Spinal Epidural Arteriovenous Fistulas

BACKGROUND

Spinal epidural arteriovenous fistulas (SEDAVFs) are an increasingly recognized form of spinal vascular malformation and are distinct from spinal dural arteriovenous fistulas (SDAVFs). Differentiating between these 2 entities is important as operative strategies often differ based on angioarchitecture.

OBJECTIVE

To compare demographic, clinical, anatomic, and imaging findings of SDAVFs and SEDAVFs.

METHODS

Consecutive patients diagnosed and/or treated for SDAVF or SEDAVF at our institution between January 2000 and November 2018 were included. Data were collected on demographics, clinical presentation, and imaging findings. All cross-sectional and angiographic imaging were reviewed. To compare continuous variables, t-test was used Chi-squared was used for categorical variables.

RESULTS

A total of 169 patients were included. In total 47 patients had SEDAVFs and 122 patients had SDVAFs. Clinical presentation and magnetic resonance imaging (MRI) imaging findings were similar between the 2 groups. SEDAVF patients were significantly more likely to have an epidural venous pouch on gadolinium bolus MR angiography (MRA) (0.0% vs 92.1%, P < .0001). SEDAVFs were more commonly located in the lumbar and sacral spine than SDAVFs (85.1% vs 34.4%, P < .0001). When in the lumbar spine, SEDAVFs unlike SDAVFs were more likely to involve the most caudal segments (L4 and L5, P = .02).

CONCLUSION

SEDAVF share clinical and radiological findings similar to SDAVFS, including high T2 cord signal, cord enhancement, and perimedullary flow voids on conventional MRI. However, they have a characteristic appearance on spinal MRA and DSA with a pouch of epidural contrast. SEDAVFs are more commonly located in the lumbosacral spine.

Per pass analysis of thrombus composition retrieved by mechanical thrombectomy

BACKGROUND AND AIM

Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT.

METHODS

Patients who required multiple passes during thrombectomy were included. Histopathological evaluation of thrombus fragments retrieved from each pass was performed using Martius Scarlet Blue staining and the composition of each thrombus component including RBC, fibrin and platelet was determined using image analysis software.

RESULTS

154 patients underwent MT and 868 passes was performed which resulted in 263 thrombus fragments retrieval. The analysis of thrombus components per pass showed higher RBC, lower fibrin and platelet composition in the pass 1 and 2 when compared to pass 3 and passes 4 or more combined (P values <0.05). There were no significant differences between thrombus fragments retrieved in pass 1 and pass 2 in terms of RBC, WBC, fibrin, and platelet composition (P values >0.05). Similarly, when each composition of thrombus fragments retrieved in pass 3 and passes 4 or more combined were compared with each other, no significant difference was noted (P values >0.05).

CONCLUSION

Our findings confirm that thrombus fragments retrieved with each pass differed significantly in histological content. Fragments in the first passes were associated with lower fibrin and platelet composition compared to fragments retrieved in passes three and four or higher. Also, thrombus fragments retrieved after failed pass were associated with higher fibrin and platelet components.

Association between clot composition and stroke origin in mechanical thrombectomy patients: analysis of the Stroke Thromboembolism Registry of Imaging and Pathology

BACKGROUND

We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiology METHODS: Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software. A Wilcoxon test was used for continuous variables and χ² test for categorical variables.

RESULTS

1350 patients were included in this study. The overall rate of Thrombolysis In Cerebral Infarction (TICI) 2c/3 was 68%. 501 patients received tissue plasminogen activator (tPA) (37%). 267 patients (20%) had a large artery atherosclerosis (LAA) source, 662 (49%) a cardioembolic (CE) source, 301 (22%) were cryptogenic, and the remainder had other identifiable sources including hypercoagulable state or dissection. LAA thrombi had a higher mean RBC density (46±23% vs 42±22%, p=0.01) and a lower platelet density (24±18% vs 27±18%, p=0.03) than CE thrombi. Clots from dissection patients had the highest mean RBC density (50±24%) while clots from patients with a hypercoagulable state had the lowest mean RBC density (26±21%).

CONCLUSIONS

Our study found statistically significant but clinically insignificant differences between clots of CE and LAA etiologies. Future studies should emphasize molecular, proteomic and immunohistochemical characteristics to determine links between clot composition and etiology.

MRS SOFIA: a multicenter retrospective study for use of Sofia for revascularization of acute ischemic stroke

BACKGROUND

Over the past several years there has been increased interest in the use of the Sofia aspiration system (MicroVention, Tustin, California) as a primary aspiration catheter.

OBJECTIVE

To perform a multicenter retrospective study examining the efficacy of the Sofia aspiration catheter as a standalone aspiration treatment for large vessel occlusion.

METHODS

Consecutive cases in which the Sofia catheter was used for aspiration thrombectomy for large vessel occlusion were included. Exclusion criteria were the following: (1) Sofia not used for first pass, and (2) a stent retriever used as an adjunct on the first pass. The primary outcome of the study was first pass recanalization (Thrombolysis in Cerebral Infarction (TICI) 2c/3). Secondary outcomes included first pass TICI 2b/3, crossover to other thrombectomy devices, number of passes, time from puncture to recanalization, and complications.

RESULTS

323 patients were included. First pass TICI 2c/3 was achieved in 49.8% of cases (161/323). First pass TICI 2b/3 was achieved in 69.7% (225/323) of cases. 74.8% had TICI 2b/3 with the Sofia alone. Crossover to other thrombectomy devices occurred in 29.1% of cases (94/323). The median number of passes was 1 (IQR=1-3). Median time from puncture to recanalization was 26 min (IQR=17-45). Procedure related complications occurred in 3.1% (10/323) of cases.

CONCLUSION

Our study highlights the potential advantage of the Sofia aspiration catheter for primary aspiration thrombectomy in acute ischemic stroke. High rates of first pass recanalization with low crossover rates to other thrombectomy devices were achieved. Median procedure time was low, as were procedural complications.

Evolution of Developmental Venous Anomalies in the Setting of a Torcular Dural Arteriovenous Fistula and Cerebrofacial Venous Metameric Syndrome

BACKGROUND

We describe evolution of a developmental venous anomaly (DVA) over time in a patient with a complex intracranial vascular malformation.

CASE DESCRIPTION

A 26-year-old male patient initially presented with a scalp vascular malformation and was later diagnosed to have a torcular dural arteriovenous fistula resembling a dural sinus malformation. The dural fistula increased in size over 4 years. The dural fistula also was associated with multiple complex developmental venous anomalies draining the bilateral cerebral hemispheres and cerebellum. The DVA was only faintly demonstrated on the baseline magnetic resonance imaging but appeared to increase in size and extent over time as the dural arteriovenous fistula developed more aggressive angioarchitecture features. In addition to the evolution manifestation of the DVAs, the patient developed multiple de novo cavernous malformations in the venous radicles of the DVA. Increased venous hypertension in the superficial venous system from the dural fistula likely resulted in growth of the DVAs, as they served as the primary means of venous drainage for the bilateral cerebral hemispheres. The patient also had reopening of the persistent falcine sinus, which was not present at baseline.

CONCLUSIONS

This would be the first reported case of growth or evolution of a DVA in association with a dural arteriovenous fistula in an adult patient and highlights the dynamic nature of both the medullary venous and dural venous sinuses of the cerebral venous system, even into adulthood.

Clinical Presentation and Imaging Findings of Patients with Dural Arteriovenous Fistulas with an Angiographic Pseudophlebitic Pattern

BACKGROUND AND PURPOSE

The pseudophlebitic pattern is an increasingly recognized angiographic manifestation of chronic venous congestion in the setting of a cranial dural arteriovenous fistula. We sought to study the clinical and radiologic manifestations of patients with the pseudophlebitic pattern.

MATERIALS AND METHODS

We retrospectively reviewed a cohort of patients with dural arteriovenous fistulas evaluated at our institution from 2008 to 2020. Angiograms were reviewed to classify dural arteriovenous fistulas and document the presence or absence of a pseudophlebitic pattern, defined as the presence of serpiginous and tortuous collateral, bridging, and cortical veins with an associated delay in circulation time of the normal brain. We then studied the association between the pseudophlebitic pattern and clinical presentation and MR imaging findings.

RESULTS

Two hundred one patients were included. Patients with a pseudophlebitic pattern had more hemorrhage (22.8% versus 8.4%, P = .005), gait changes and ataxia (6.0% versus 0.0%, P = 0.002), cognitive changes (6.9% versus 1.4%, P = .04), and seizures (8.6% versus 2.1%, P = .03). On MR imaging, the pseudophlebitic pattern was associated with higher rates of cerebral edema (70.9% versus 2.9%, P < .0001), chronic hemosiderin deposition and microhemorrhage (17.3% versus 2.2%, P = .0002), and dilated transmedullary veins (47.1% versus 0.0%, P < .0001). When we considered only patients with malignant fistulas, there was no difference in hemorrhage at presentation between the 2 groups (22.6% versus 22.8%, P = .99). Patients with a pseudophlebitic pattern did have higher rates of nonhemorrhagic neurologic deficits (24.1% versus 9.4%, P = .03).

CONCLUSIONS

The pseudophlebitic pattern was associated with high rates of brain parenchymal changes and neurologic symptoms in this cohort of patients with dural arteriovenous fistulas.

Transvenous embolization of a posterior condylar canal fistula causing pulsatile tinnitus

Dural arteriovenous fistulas of the skull base commonly present with pulsatile tinnitus. In our experience, transvenous embolization of dural arteriovenous fistulas of the skull base represents a safe and effective treatment modality due to its precision in treatment of the site of convergence of all feeding arteries and the low risk of ischemic complications. We present a case of an adult patient who presented to our institution with pulsatile tinnitus several months following a motor vehicle accident. Cerebral angiography demonstrated a dural arteriovenous fistula at the junction of the posterior condylar vein and suboccipital venous plexus supplied by branches of the vertebral artery, occipital artery, and ascending pharyngeal artery. In this operative video we demonstrate this technique and provide an in-depth discussion of our treatment decision-making process and the anatomical considerations involved in treating this lesion.

Clinical, angiographic, and treatment characteristics of cranial dural arteriovenous fistulas with pial arterial supply

BACKGROUND

The prevalence of pial arterial supply to cranial dural arteriovenous fistulas (dAVF) and its implication in the management of these fistulas is not well characterized. We performed a retrospective study to characterize pial arterial supply to dural arteriovenous fistulas and the implications for treatment.

METHODS

Consecutive patients evaluated over a 12-year period were retrospectively reviewed. Angiograms were reviewed to characterize dAVF angioarchitecture and the presence of pial artery supply. Pial artery supply was categorized as dilated pre-existing dural branches and pure pial supply. We then studied the association between pial artery supply and clinical, angiographic, and treatment features.

RESULTS

A total of 201 patients were included of which 27 (13.4%) had pial artery supply. Of these, 11 had supply from dilated pre-existing dural branches, nine had pure pial supply,and seven had both. There was a higher rate of dAVF rupture in the pial supply group (30.8% vs 9.8%, P=0.003) and these fistulas had a higher rate of Borden 2 and 3 (88.9% vs 38.4%, P<0.0001). Fistulas with pial artery supply had similar rates of endovascular and gamma knife treatment, but were more likely to undergo surgery than those without pial supply (25.9% vs 10.4%, P=0.03). Major complication rates were similar between groups (0% vs 1.1%, P=0.55).

CONCLUSIONS

More than 10% of dAVFs also have pial supply but this is not a contraindication to embolization. In our study pure pial supply was associated with a more aggressive fistula and was most common in tentorial dAVFs.

Beyond plaque: A pictorial review of non-atherosclerotic abnormalities of extracranial carotid arteries

The common carotid artery (CCA) and extracranial internal carotid artery are subject to a wide variety of non-atheromatous pathologies. These entities are often overshadowed in both research and clinical realms by atherosclerotic disease. Nevertheless, non-atherosclerotic disease of the carotid arteries may have profound, even devastating, neurologic consequences. Hence, this review will cover both common and uncommon forms of extracranial carotid artery pathologies in a pictorial format, in order to aid the diagnostician in identifying and differentiating such pathologies.

Abstract 68: Impaired Perfusion in Intracranial Atherosclerotic Disease Predicts Cognitive Outcomes

Background: Poor collateral circulation and hypoperfusion may lead to recurrent stroke in intracranial atherosclerotic disease (ICAD). The role of perfusion in silent strokes and potentially insidious cognitive impairment in ICAD is unknown. We used evidence of impaired perfusion at angiography in SAMMPRIS to predict subsequent cognitive changes.

Methods: Angiography at enrollment in the SAMMPRIS trial was independently evaluated, blind to clinical data and cognitive testing. Antegrade flow in the symptomatic arterial territory and corresponding collateral flow were scored. Impaired perfusion was defined by poor antegrade and poor collateral flow. Serial testing with the Montreal Cognitive Assessment (MoCA) was done in subjects without aphasia or neglect at baseline, 4 mo, 12 mo and closeout, or until subjects had a clinical stroke endpoint.

Results: 207 subjects (median age 61, range 33-81 years; 37% women) had baseline MoCA scores with angiography data on territorial perfusion. Baseline MoCA scores (mean 24.2±4.1) were similar between categories of antegrade flow and collateral circulation. Impaired perfusion was noted in 33/207 (16%). Serial MoCA revealed that changes in cognition over time were different at 4 mo, 12 mo and closeout based on the presence of impaired perfusion at baseline (p<0.001). After more modest (mean MoCA change = 0.5 increase from baseline, p=0.80) early improved cognitive function at 4 mo, those with impaired perfusion had cognitive decline at 12 mo (mean MoCA change, p<0.01) unlike the continued improvement in other subjects. Cognitive changes in those with impaired perfusion were associated with a higher frequency of subsequent stroke in the territory.

Conclusions: Impaired perfusion in the symptomatic arterial territory of ICAD predicts cognitive outcomes that may precede recurrent ischemia. Future studies may define the role of noninvasive perfusion imaging in ICAD to predict cognitive trajectories and recurrent stroke.

Hemangioblastoma of the pons and middle cerebellar peduncle

A 60-year-old man with a history of four prior operations for a left cerebellar/middle cerebellar peduncle hemangioblastoma presented with hearing loss, imbalance, and ataxia (de la Monte and Horowitz, 1989). Magnetic resonance imaging (MRI) demonstrated a 3-cm cystic mass with heterogeneous enhancement in the same location. We resected the mass via reopening of the retrosigmoid approach (Lee et al., 2014). Left cranial nerves IV, V, VII, VIII, IX, X, and XI were all well identified and preserved, and feeding arteries from the brainstem were meticulously coagulated and transected without violating the tumor-brainstem interface (Chen et al., 2013). Preoperative embolization greatly aided safe resection of the mass, whose pathology revealed recurrence of hemangioblastoma (Eskridge et al., 1996; Kim et al., 2006; Sakamoto et al., 2012).

The video can be found here: https://youtu.be/3mZgY15xOZc.

Remote ischemic preconditioning for elective endovascular intracranial aneurysm repair: a feasibility study

OBJECTIVES

Remote ischemic preconditioning has been proposed as a possible potential treatment for ischemic stroke. However, neuroprotective benefits of the pre-procedural administration of remote ischemic preconditioning have not been investigated in patients undergoing an elective endovascular intracranial aneurysm repair procedure. This study investigated the safety and feasibility of remote ischemic preconditioning in patients with an unruptured intracranial aneurysm who undergo elective endovascular treatment.

METHODS

In this single-center prospective study, patients with an unruptured intracranial aneurysm undergoing elective endovascular treatment with flow diverters or coiling were recruited. Patients received three intermittent cycles of 5 minutes arm ischemia followed by reperfusion using manual blood cuff inflation/deflation less than 5 hours prior to endovascular treatment. Patients were monitored and followed up for remote ischemic preconditioning-related adverse events and ischemic brain lesions by diffusion -weighted magnetic resonance imaging within 48 hours following endovascular treatment.

RESULTS

A total of seven patients aged 60 ± 5 years with an unruptured intracranial aneurysm successfully completed a total of 21 sessions of remote ischemic preconditioning and the required procedures. Except for two patients who developed skin petechiae over their arms, no other serious procedure-related adverse events were observed as a result of the remote ischemic preconditioning procedure. On follow-up diffusion -weighted magnetic resonance imaging, a total of 19 ischemic brain lesions with a median (interquartile range) volume of 245 (61-466) mm³ were found in four out of seven patients.

CONCLUSIONS

The application of remote ischemic preconditioning prior to endovascular intracranial aneurysm repair was well tolerated, safe and clinically feasible. Larger sham-controlled clinical trials are required to determine the safety and efficacy of this therapeutic strategy in mitigating ischemic damage following endovascular treatment of intracranial aneurysms.

Accuracy of detecting enlargement of aneurysms using different MRI modalities and measurement protocols

OBJECTIVE

Aneurysm growth is considered predictive of future rupture of intracranial aneurysms. However, how accurately neuroradiologists can reliably detect incremental aneurysm growth using clinical MRI is still unknown. The purpose of this study was to assess the agreement rate of detecting aneurysm enlargement employing generally used MRI modalities.

METHODS

Three silicone flow phantom models, each with 8 aneurysms of various sizes at different sites, were used in this study. The aneurysm models were identical except for an incremental increase in the sizes of the 8 aneurysms, which ranged from 0.4 mm to 2 mm. The phantoms were imaged on 1.5-T and 3-T MRI units with both time-of-flight (TOF) and contrast-enhanced MR angiography. Three independent expert neuroradiologists measured the aneurysms in a blinded manner using different measurement approaches. The individual and agreement detection rates of aneurysm enlargement among the 3 experts were calculated.

RESULTS

The mean detection rate of any increase in any aneurysmal dimension was 95.7%. The detection rates of the 3 observers (observers A, B, and C) were 98.0%, 96.6%, and 92.7%, respectively (p = 0.22). The detection rates of each MRI modality were 91.3% using 1.5-T TOF, 97.2% using 1.5-T with Gd, 95.8% using 3.0-T TOF, and 97.2% using 3.0-T with Gd (p = 0.31). On the other hand, the mean detection rate for aneurysm enlargement was 54.8%. Specifically, the detection rates of observers A, B, and C were 49.0%, 46.1%, and 66.7%, respectively (p = 0.009). As the incremental enlargement value increased, the detection rate for aneurysm enlargement increased. The use of 1.5-T Gd improved the detection rate for small incremental enlargement (e.g., 0.4–1 mm) of the aneurysm (p = 0.04). The location of the aneurysm also affected the detection rate for aneurysm enlargement (p < 0.0001).

CONCLUSIONS

The detection rate and interobserver agreement were very high for aneurysm enlargement of 0.4–2 mm. The detection rate for at least 1 increase in any aneurysm dimension did not depend on the choice of MRI modality or measurement protocol. Use of Gd improved the accuracy of measurement. Aneurysm location may influence the accuracy of detecting enlargement.

Abstract WP161: Computational Fluid Dynamics Using SAMMPRIS CT Angiography Quantifies Pro-Atherogenic Shear Stress Linked With Post-Stenotic Flow Vortices

Background: Low wall shear stress (LSS) is an established cause of pro-atherogenic endothelial pathophysiology, yet it has never been demonstrated in the cerebral circulation affected by intracranial atherosclerotic disease (ICAD). Noninvasive CT angiography (CTA) computational fluid dynamics (CFD) enables high-resolution investigation of detailed post-stenotic phenomena. We used all available CTA data in the SAMMPRIS trial of ICAD to detect and quantify post-stenotic LSS.

Methods: CTA source images from SAMMPRIS were reconstructed in 3D followed by geometry refinements to generate a mesh of the diseased arterial lesion and adjacent segments. CFD was performed with Ansys (ICEM, Fluent), applying reference boundary conditions with k-omega turbulence and non-Newtonian modeling of the traversing blood viscosity. 3D CFD parameter maps illustrated velocity, velocity swirling and corresponding wall shear stress.

Results: 144 subjects enrolled in SAMMPRIS had CTA at baseline, including 140 with CTA source images enabling CFD. Post-stenotic velocity profiles revealed vortices in all cases, quantified by swirling and turbulent kinetic energy. These luminal flow changes were adjacent to focal regions of LSS in the post-stenotic region (Figure).

Conclusions: Low wall shear stress is associated with vortices of fluid flow in CTA CFD modeling of ICAD from SAMMPRIS. CTA source images may be used to noninvasively quantify LSS and model this pro-atherogenic factor in ICAD across a wide variety of lesions. Future studies should examine the related endothelial biology and potential link with plaque evolution.

Racial and economic disparities in the access to treatment of unruptured intracranial aneurysms are persistent problems

Background and purpose

Previous studies have documented disparate access to cerebrovascular neurosurgery for patients of different racial and socioeconomic backgrounds. We further investigated the effect of race and insurance status on access to treatment of unruptured intracranial aneurysms (UIAs) and compared it with data on patients with aneurysmal subarachnoid hemorrhage (aSAH).

Methods

Through the use of a national database, admissions for clipping or coiling of an UIA and for aSAH were identified. Demographic characteristics of patients were characterized according to age, sex, race/ethnicity, and insurance status, and comparisons between patients admitted for treatment of an UIA versus aSAH were performed.

Results

There were 10 545 admissions for clipping or coiling of an UIA and 33 166 admissions for aSAH between October 2014 and July 2018. White/non-Hispanic patients made up a greater proportion of patients presenting for treatment of an UIA than those presenting with aSAH (64.3% vs 48.2%; P<0.001), whereas black/Hispanic patients presented more frequently with aSAH than for treatment of an UIA (29.3% vs 26.1%; P=0.006). On multivariate linear regression analysis, the proportion of patients admitted for management of an UIA relative to those admitted for aSAH increased with the proportion of patients who were women (P<0.001) and decreased with the proportion of patients with a black/Hispanic background (P=0.010) and those insured with Medicaid or without insurance (P=0.003).

Conclusion

For patients with UIAs, racial, ethnic, and socioeconomic backgrounds appear to continue to influence access to treatment.

Utilization rates of tissue plasminogen activator and mechanical thrombectomy in patients with acute stroke and underlying malignancy

Objective

Relatively little is known about the effect of malignancy on patient outcomes after acute ischemic stroke (AIS) or utilization rates of stroke interventions in this population. We aimed to assess the effect of underlying malignancy on outcomes and treatment of AIS at a population level.

Methods

Outcomes after AIS between patients with and without malignancy were compared using a national database of hospital reported outcomes.

Results

There were 351 institutions reporting the outcomes of 3 18 127 admissions for AIS. Of these admissions, 16 141 patients carried a pre-existing diagnosis of malignancy at the time of admission. Administration of intravenous tissue plasminogen activator (IV tPA) was less common in patients with malignancy compared with patients without malignancy (7.3% vs 10.7%; P<0.001) but there was no difference in the rate of mechanical thrombectomy (3.1% vs 3.1%; P=0.967). Mortality rates were higher among patients with malignancy (7.1% vs 3.7%; P<0.001), a relationship which persisted when analysis was restricted to patients receiving IV tPA (10.8% vs 6.1%; P<0.001) or thrombectomy (20.3% vs 13.5%; P<0.001). Rates of both IV tPA administration (2.5% vs 10.5%; P<0.001) and mechanical thrombectomy (2.1% vs 5.4%; P<0.001) were lower in patients with brain malignancy relative to patients with malignancy of non-CNS origin.

Conclusion

A diagnosis of malignancy on admission for acute stroke was associated with a higher rate of mortality. Malignancy was also associated with a lower rate of IV tPA administration but no difference in mechanical thrombectomy utilization.

Transarterial embolization of an internal maxillary artery arteriovenous fistula presenting with pulsatile tinnitus

Arteriovenous fistulae of the internal maxillary artery are exceedingly rare, with less than 30 cases reported in the literature. Most of these lesions are congenital, iatrogenic, or posttraumatic. The most common presentation of internal maxillary artery fistulae is pulsatile tinnitus and headache. Because these lesions are single-hole fistulae, they can be easily cured with endovascular techniques. The authors present a case of a patient who presented to their institution with a several-year history of pulsatile tinnitus who was found to have an internal maxillary artery arteriovenous fistula, which was treated endovascularly with transarterial coil and Onyx embolization.

The video can be found here: https://youtu.be/fDZVMMwpwRc.

Effect of Carotid Siphon Anatomy on Aneurysm Occlusion After Flow Diversion for Treatment of Internal Carotid Artery Aneurysms

BACKGROUND

Flow diversion (FD) is effective for treatment of intracranial internal carotid artery (ICA) aneurysms.

OBJECTIVE

To determine whether carotid siphon (CS) geometry influences the efficacy of FD when employed for ICA aneurysms.

METHODS

Outcomes of a consecutive series of patients with ICA aneurysms treated with FD were retrospectively reviewed. CS anatomy was quantified through measurement of the posterior, anterior, and anterosuperior bend angles in accordance with previously described methodology. The relationship of CS geometry to likelihood of incomplete aneurysm occlusion at 1 yr after treatment was assessed with multivariate logistic regression analysis.

RESULTS

There were 167 ICA aneurysms in 164 patients treated with FD during the study period. The mean age of our cohort was 55.7 yr (standard deviation [SD]: 12.3) and a majority of patients were female (145/164, 86.8%). Anterior (47.4 degrees vs 8.5, P < .001) and anterosuperior bend angles (100.9 vs 76.5, P = .002) were significantly greater in aneurysms that required repeat FD after initial treatment. On multivariate logistic regression analysis, increasing patient age (unit odds ratio [OR]: 1.05, 95% confidence interval [CI] 1.01-1.08; P = .003) and anterior bend angle ≥–3.5 (OR: 2.47, 95% CI 1.04-5.86; P = .046) were associated with increased odds of incomplete aneurysm occlusion at 1 yr after treatment.

CONCLUSION

These findings suggest that variations in CS anatomy may influence the efficacy of FD treatment and should be analyzed prior to offering FD for treatment of ICA aneurysms. Further investigation into the hemodynamic effects of CS geometry is warranted.

Pure arterial malformations

OBJECTIVE

Over the last half century, there have been isolated case reports of purely arterial malformations. In this study, the authors report a consecutive series of patients with pure arterial malformations, emphasizing the clinical and radiological features of these lesions.

METHODS

Pure arterial malformations were defined as dilated, overlapping, and tortuous arteries with a coil-like appearance and/or a mass of arterial loops without any associated venous component. Demographic characteristics of the patients, cardiovascular risk factors, presentation, radiological characteristics, and follow-up data were collected. Primary outcomes were new neurological symptoms including disability, stroke, and hemorrhage.

RESULTS

Twelve patients meeting the criteria were identified. Ten patients were female (83.3%) and 2 were male (16.6%). Their mean age at diagnosis was 26.2 ± 11.6 years. The most common imaging indication was headache (7 patients [58.3%]). In 3 cases the pure arterial malformation involved the anterior cerebral arteries (25.0%); in 4 cases the posterior communicating artery/posterior cerebral artery (33.3%); in 2 cases the middle cerebral artery (16.6%); and in 1 case each, the superior cerebellar artery, basilar artery/anterior inferior cerebellar artery, and posterior inferior cerebellar artery. The mean maximum diameter of the malformations was 7.2 ± 5.0 mm (range 3–16 mm). Four lesions had focal aneurysms associated with the pure arterial malformation, and 5 were partially calcified. In no cases was there associated intracranial hemorrhage or infarction. One patient underwent treatment for the pure arterial malformation. All 12 patients had follow-up (mean 29 months, median 19 months), and there were no cases of disability, stroke, or hemorrhage.

CONCLUSIONS

Pure arterial malformations are rare lesions that are often detected incidentally and probably have a benign natural history. These lesions can affect any of the intracranial arteries and are likely best managed conservatively.

Periprocedural safety of Pipeline therapy for unruptured cerebral aneurysms: Analysis of 279 Patients in a multihospital database

The relative safety of unruptured aneurysm treatment with coiling versus flow diversion therapy is unknown. Most data available on flow diversion reflect highly focused patient groups and very experienced operators. We evaluated a national, multihospital patient database to examine periprocedural morbidity and mortality in patients treated with endovascular flow diversion therapy. The Premier Perspective database was used to identify patients hospitalized between May 2011 and March 2013 for unruptured aneurysm who underwent flow diversion therapy with a Pipeline embolization device. The risk of in-hospital mortality and morbidity was determined using ICD 9 codes. A total of 279 unruptured aneurysm patients at 18 medical centers underwent endovascular therapy with a Pipeline device. Adverse outcomes included in-hospital mortality in two cases (0.7%), discharge to long-term care in 22 cases (7.9%), ischemic complications in 14 cases (5.0%), hemorrhagic complications in four cases (1.4%), and postoperative neurological complications in nine cases (3.2%). This study of a large cohort of patient hospitalizations in the United States provides preliminary data on flow diversion in a "real world" scenario and demonstrates that the periprocedural morbidity and mortality is not negligible and must be considered in the context of the natural history of the aneurysms that are being treated.

Endovascular treatment of carotid blowout syndrome

BACKGROUND

Carotid blowout syndrome (CBS) is a life-threatening complication of head and neck cancer and radiation therapy. Endovascular techniques have emerged as preferable alternatives to surgical ligation for treatment of CBS. We performed a systematic review and meta-analysis to study periprocedural complications and outcomes of CBS patients treated with coil embolization and covered stents.

METHODS

A comprehensive literature search identified studies that reported outcomes of endovascular treatment of CBS published from 2000 to April 2016. Outcomes included technical success, postoperative rebleeding, survival time, and perioperative complications. Meta-analyses were performed using a random-effects model.

RESULTS

Twenty-five noncomparative studies with 559 patients were included in the meta-analysis. Technical success rate was 100% in both coiling and covered stenting groups. Median survival time was 3 months (range, 0-96 months) for all CBS patients. Overall perioperative mortality was 11% (95% confidence interval [CI], 5%-17%). Postoperative rebleeding rate was 27% (95% CI, 19%-367%). Perioperative stroke and infection rates were 3% (95% CI, 1%-6%) and 1% (95% CI, 0%-5%), respectively. At last follow-up, 39% of patients were alive (95% CI, 29%-48%).

CONCLUSIONS

Coil embolization and stent grafts may both be safe treatment options for CBS with few perioperative complications and high rates of technical success, but prognosis after treatment remains poor. In general, noncomparative studies do not demonstrate differences between the two techniques with respect to periprocedural complications and patient outcomes.

Clinical and Imaging Characteristics of Diffuse Intracranial Dolichoectasia

BACKGROUND AND PURPOSE

Among patients with vertebrobasilar dolichoectasia is a subset of patients with disease affecting the anterior circulation as well. We hypothesized that multivessel intracranial dolichoectasia may represent a distinct phenotype from single-territory vertebrobasilar dolichoectasia. The purpose of this study was to characterize clinical characteristics and angiographic features of this proposed distinct phenotype termed "diffuse intracranial dolichoectasia" and compare them with those in patients with isolated vertebrobasilar dolichoectasia.

MATERIALS AND METHODS

We retrospectively reviewed a consecutive series of patients with diffuse intracranial dolichoectasia and compared their demographics, vascular risk factors, additional aneurysm prevalence, and clinical outcomes with a group of patients with vertebrobasilar dolichoectasia. "Diffuse intracranial dolichoectasia" was defined as aneurysmal dilation of entire vascular segments involving ≥2 intracranial vascular beds. Categoric and continuous variables were compared by using χ² and Student t tests, respectively.

RESULTS

Twenty-five patients had diffuse intracranial dolichoectasia, and 139 had vertebrobasilar dolichoectasia. Patients with diffuse intracranial dolichoectasia were older than those with vertebrobasilar dolichoectasia (70.9 ± 14.2 years versus 60.4 ± 12.5 years, P = .0002) and had a higher prevalence of abdominal aortic aneurysms (62.5% versus 14.3%, P = .01), other visceral aneurysms (25.0% versus 0%, P < .0001), and smoking (68.0% versus 15.9%, P < .0001). Patients with diffuse intracranial dolichoectasia were more likely to have aneurysm growth (46.2% versus 21.5%, P = .09) and rupture (20% versus 3.5%, P = .007) at follow-up. Patients with diffuse intracranial dolichoectasia were less likely to have good neurologic function at follow-up (24.0% versus 57.6%, P = .004) and were more likely to have aneurysm-related death (24.0% versus 7.2%, P = .02).

CONCLUSIONS

The natural history of patients with diffuse intracranial dolichoectasia is significantly worse than that in those with isolated vertebrobasilar dolichoectasia. Many patients with diffuse intracranial dolichoectasia had additional saccular and abdominal aortic aneurysms. These findings suggest that diffuse intracranial dolichoectasia may be a distinct vascular phenotype secondary to a systemic arteriopathy affecting multiple vascular beds.

Intracranial and Extracranial Neurovascular Manifestations of Takayasu Arteritis

BACKGROUND AND PURPOSE

Takayasu arteritis is a rare, large-vessel vasculitis that presents with symptoms related to end-organ ischemia. While the extracranial neurovascular manifestations of Takayasu arteritis are well-established, little is known regarding the intracranial manifestations. In this study, we characterize the intracranial and cervical neurovascular radiologic findings in patients with Takayasu arteritis.

MATERIALS AND METHODS

Patients with Takayasu arteritis who presented to our institution between 2001 and 2016 with intracranial and/or cervical vascular imaging were included in this study. Images were evaluated for the presence of vascular abnormalities, including intracranial or extracranial stenosis, vessel-wall thickening, dissection, subclavian steal, aneurysms, infarcts, and hemorrhages. Descriptive analyses are reported.

RESULTS

Seventy-nine patients with Takayasu arteritis met the criteria for inclusion in this study. The most common presenting neurologic symptoms were headache (32.9%) and dizziness (15.2%). Intracranial and extracranial vascular imaging was performed in 84.8% and 89.9% of patients, respectively. Among patients with intracranial vascular imaging, 3 (3.9%) had intracranial aneurysms, 3 (3.9%) had acute large-vessel occlusion, 6 (7.6%) had intracranial vasculitis, and 1 (1.3%) had reversible cerebrovascular constriction syndrome. Among patients with cervical vascular imaging, 42 (53.1%) had some degree of narrowing of the common carotid artery and 18 (22.8%) had narrowing of the ICAs. Seventeen patients (23.6%) had subclavian steal.

CONCLUSIONS

Intracranial vascular abnormalities in patients with Takayasu arteritis presenting with neurologic symptoms are not rare, with cerebral vasculitis seen in 7.8% of patients, and stroke secondary to large-vessel occlusion, in 3.9% of patients. Cervical vascular manifestations of Takayasu arteritis were present in most patients in our study.

Capillary Index Score and Correlation with Outcomes in Acute Ischemic Stroke: A Meta-analysis

BACKGROUND AND PURPOSE

The capillary index score (CIS) has been recently introduced as a metric for rating the collateral circulation of ischemic stroke patients. Multiple studies in the last five years have evaluated the correlation of good CIS with clinical outcomes and suggested the use of CIS in selecting patients for endovascular treatment. We performed a meta-analysis of these studies comparing CIS with clinical outcomes.

METHODS

We conducted a computerized search of three databases from January 2011 to November 2015 for studies related to CIS and outcomes. A CIS = 0 or 1 is considered poor (pCIS) and a CIS = 2 or 3 is considered favorable (fCIS). Using random-effect meta-analysis, we evaluated the relationship of CIS to neurological outcome (modified Rankin scale score ≤ 2), recanalization, and post-treatment hemorrhage. Meta-regression analysis of good neurological outcome was performed for adjusting baseline National Institutes of Health Stroke Scale (NIHSS) between groups.

RESULTS

Six studies totaling 338 patients (212 with fCISs and 126 with pCISs) were included in the analysis. Patients with fCIS had higher likelihood of good neurological outcome [relative risk (RR) = 3.03; confidence interval (CI) = 95%, 2.05-4.47; p < 0.001] and lower risk of post-treatment hemorrhage (RR = 0.38; CI = 95%, 0.19-0.93; p = 0.04) as compared with patients in the pCIS group. When adjusting for baseline NIHSS, patients with fCIS had higher RR of good neurological outcome when compared with those with pCIS (RR = 2.94; CI = 95%, 1.23-7, p < 0.0001). Favorable CIS was not associated with higher rates of recanalization.

CONCLUSIONS

Observational evidence suggests that acute ischemic stroke patients with fCIS may have higher rates of good neurological outcomes compared with patients with pCIS, independent of baseline NIHSS. CIS may be used as another tool to select patients for endovascular treatment of acute ischemic stroke.

Effect of Center Volume on Outcomes in Hospitalized Patients With Hereditary Hemorrhagic Telangiectasia

OBJECTIVE

To determine whether hospitalized patients with hereditary hemorrhagic telangiectasia (HHT) had better outcomes at high-volume treatment centers (HVCs).

PATIENTS AND METHODS

The Nationwide Inpatient Sample (2000-2011) was used to identify HHT-related hospitalizations. Hospitals were classified based on quartiles of annual HHT discharge volume. The 75th percentile cutoff value (third quartile) was used to classify hospitals as low-volume centers (1-7 HHT discharges per year) or as HVCs (≥8 discharges per year. Demographic features, complication rates, and outcomes were compared between the 2 groups.

RESULTS

We identified 9440 hospital discharges in patients with HHT. Of these patients, 6856 (72.6%) were admitted to low-volume centers and 2584 (27.4%) to HVCs. The former were more likely to be of white race, older, and with higher income levels (P<.001 for each). The HVCs had higher rates of anemia, epistaxis, congestive heart failure, pulmonary hypertension, and cerebral and pulmonary arteriovenous malformations and lower rates of ischemic stroke and myocardial infarction. After adjusting for baseline differences in a multivariate model, patients treated at HVCs were more likely to be discharged home (odds ratio [OR]=1.35; 95% CI, 1.21-1.52; P<.001) and less likely to be discharged to short-term rehabilitation facilities (OR=0.45; 95% CI, 0.31-0.64; P<.001). Patients treated at HVCs also had a significantly lower risk of in-hospital mortality (OR=0.51; 95% CI, 0.34-0.74; P<.001).

CONCLUSION

Patients with HHT hospitalized at HVCs had better outcomes, with lower in-hospital mortality and higher home discharge rates. These findings strongly support ongoing efforts to expand access to HHT centers of excellence in the United States and worldwide.

Diffusion-Weighted Imaging-Detected Ischemic Lesions following Endovascular Treatment of Cerebral Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Endovascular treatment of intracranial aneurysms is associated with the risk of thromboembolic ischemic complications. Many of these events are asymptomatic and identified only on diffusion-weighted imaging. We performed a systematic review and meta-analysis to study the incidence of DWI positive for thromboembolic events following endovascular treatment of intracranial aneurysms.

MATERIALS AND METHODS

A comprehensive literature search identified studies published between 2000 and April 2016 that reported postprocedural DWI findings in patients undergoing endovascular treatment of intracranial aneurysms. The primary outcome was the incidence of DWI positive for thromboembolic events. We examined outcomes by treatment type, sex, and aneurysm characteristics. Meta-analyses were performed by using a random-effects model.

RESULTS

Twenty-two studies with 2148 patients and 2268 aneurysms were included. The overall incidence of DWI positive for thromboembolic events following endovascular treatment was 49% (95% CI, 42%-56%). Treatment with flow diversion trended toward a higher rate of DWI positive for lesions than coiling alone (67%; 95% CI, 46%-85%; versus 45%; 95% CI, 33%-56%; P = .07). There was no difference between patients treated with coiling alone and those treated with balloon-assisted (44%; 95% CI, 29%-60%; P = .99) or stent-assisted (43%; 95% CI, 24%-63%; P = .89) coiling. Sex, aneurysm rupture status, location, and size were not associated with the rate of DWI positive for lesions.

CONCLUSIONS

One in 2 patients may have infarcts on DWI following endovascular treatment of intracranial aneurysms. There is a trend toward a higher incidence of DWI-positive lesions following treatment with flow diversion compared with coiling. Patient demographics and aneurysm characteristics were not associated with DWI-positive thromboembolic events.

Unruptured internal carotid artery bifurcation aneurysms: general features and overall results after modern treatment

BACKGROUND

Internal carotid artery bifurcation aneurysms (ICAbifAs) present unique challenges to endovascular and surgical operators, and little is known about their natural history. We reviewed our institution's experience with ICAbifAs studying outcomes of surgical and endovascular management and natural history.

METHODS

Consecutive patients with unruptured ICAbifAs evaluated and/or treated over an 8-year interval were studied. Baseline demographics, neurovascular risk factors, aneurysm location and size, clinical presentation, treatment recommendations, and outcomes were prospectively collected and retrospectively analyzed. Continuous variables were compared with Student's t test and categorical variables with Chi-square tests.

RESULTS

Fifty-nine patients with 61 unruptured ICAbifAs were included. Seven aneurysms were treated surgically (11.5 %), 22 underwent endovascular treatment (36 %), and 32 were managed conservatively (52.5 %). In the surgical group, short- and long-term complete aneurysm occlusion rates were 100 % with no cases of perioperative or long-term permanent morbidity or treatment-related mortality. In the endovascular group, two patients (11.7 %) with giant aneurysms had perioperative thromboembolic events with transient morbidity. There was one case of aneurysm rupture at follow-up in a giant aneurysm treated with partial coil embolization. Complete/near-complete occlusion rates were 63 %. There was one case of aneurysm rupture after 114 aneurysm-years of follow-up in the conservative management group (0.89 %/year), but no ruptures were observed in small aneurysms selected for conservative management.

CONCLUSIONS

Unruptured small ICAbifAs have a benign natural history. In patients selected for treatment, excellent results can be achieved in the vast majority of patients with judicious use of endovascular and surgical therapy.

Endovascular Coiling of Wide-Neck and Wide-Neck Bifurcation Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

We present the results of a systematic review and meta-analysis examining outcomes of endovascular coiling of wide-neck and wide-neck bifurcation aneurysms with and without stent assistance. The aim of our study was to assess angiographic and clinical outcomes.

MATERIALS AND METHODS

We performed a comprehensive literature search for all articles on the endovascular coiling of wide-neck and wide-neck bifurcation aneurysms. Studies meeting our inclusion criteria and abstracted data were selected by 2 independent reviewers. Primary outcomes were >6-month complete or near-complete angiographic occlusion, aneurysm recanalization, and aneurysm retreatment. Secondary outcomes included initial complete or near-complete occlusion, long-term good neurologic outcome, procedure-related morbidity, and procedure-related mortality. Data were analyzed by using random-effects meta-analysis.

RESULTS

In total, 38 studies including 2446 patients with 2556 aneurysms were included. For all wide-neck aneurysms, immediate complete or near-complete occlusion rate was 57.4% (95% CI, 48.1%-66.8%). Follow-up near-complete occlusion rate was 74.5% (95% CI, 68.0%-81.0%). Recanalization and retreatment rates were 9.4% (95% CI, 7.1%-11.7%) and 5.8% (95% CI, 4.1%-7.5%), respectively. Long-term good neurologic outcome was 91.4% (95% CI, 88.5%-94.2%). For wide-neck bifurcation aneurysms, initial complete or near-complete occlusion rate was 60.0% (95% CI, 42.7%-77.3%), long-term complete or near-complete occlusion rate was 71.9% (95% CI, 52.6%-91.1%), and the recanalization and retreatment rates were 9.8% (95% CI, 7.1%-12.5%) and 5.2% (95% CI, 1.9%-8.4%), respectively.

CONCLUSIONS

Our study of angiographic and clinical outcomes for patients with wide-neck aneurysms demonstrates that endovascular coiling with or without stent-assisted coiling is safe, with low rates of perioperative morbidity and mortality. Initial and long-term angiographic outcomes were generally satisfactory, but not ideal. These data provide some baseline comparisons against which emergent technologies can be assessed.

Nonaneurysmal Perimesencephalic Hemorrhage Is Associated with Deep Cerebral Venous Drainage Anomalies: A Systematic Literature Review and Meta-Analysis

BACKGROUND AND PURPOSE

Mechanisms underlying bleeding in nonaneurysmal perimesencephalic SAH remain unclear. Previous investigators have suggested a relationship between nonaneurysmal perimesencephalic SAH and primitive venous drainage of the basal vein of Rosenthal. We performed a meta-analysis to evaluate the relation between primitive basal vein of Rosenthal drainage and nonaneurysmal perimesencephalic SAH.

MATERIALS AND METHODS

We performed a comprehensive literature search of all studies examining the prevalence of primitive basal vein of Rosenthal drainage in patients with aneurysmal SAH and nonaneurysmal perimesencephalic SAH. Data collected were primitive basal vein of Rosenthal drainage (direct connection of perimesencephalic veins into the dural sinuses instead of the Galenic system) in at least 1 cerebral hemisphere, normal bilateral basal vein of Rosenthal drainage systems, and the number of overall primitive venous systems in the nonaneurysmal perimesencephalic SAH and aneurysmal SAH groups. Statistical analysis was performed by using a random-effects meta-analysis.

RESULTS

Eight studies with 888 patients (334 with nonaneurysmal perimesencephalic SAH and 554 with aneurysmal SAH) and 1657 individual venous systems were included. Patients with nonaneurysmal perimesencephalic SAH were more likely to have a primitive basal vein of Rosenthal drainage in at least 1 hemisphere (47.7% versus 22.1%; OR, 3.31; 95% CI, 2.15-5.08; P < .01) and were less likely to have bilateral normal basal vein of Rosenthal drainage systems than patients with aneurysmal SAH (18.3% versus 37.4%; OR, 0.27; 95% CI, 0.14-0.52; P < .01). When we considered individual venous systems, there were higher rates of primitive venous systems in patients with nonaneurysmal perimesencephalic SAH than in patients with aneurysmal SAH (34.9% versus 15.3%; OR, 3.90; 95% CI, 2.37-6.43; P < .01).

CONCLUSIONS

Patients with nonaneurysmal perimesencephalic SAH have a higher prevalence of primitive basal vein of Rosenthal drainage in at least 1 hemisphere than patients with aneurysmal SAH. This finding suggests a venous origin of some nonaneurysmal perimesencephalic SAHs. A primitive basal vein of Rosenthal pattern is an imaging finding that has the potential to facilitate the diagnosis of nonaneurysmal perimesencephalic SAH.

Risk Factors for Ischemic Complications following Pipeline Embolization Device Treatment of Intracranial Aneurysms: Results from the IntrePED Study

BACKGROUND AND PURPOSE

Risk factors for acute ischemic stroke following flow-diverter treatment of intracranial aneurysms are poorly understood. Using the International Retrospective Study of Pipeline Embolization Device (IntrePED) registry, we studied demographic, aneurysm, and procedural characteristics associated with postoperative acute ischemic stroke following Pipeline Embolization Device (PED) treatment.

MATERIALS AND METHODS

We identified patients in the IntrePED registry with post-PED-treatment acute ischemic stroke. The rate of postoperative acute ischemic stroke was determined by demographics, comorbidities, aneurysm characteristics, and procedure characteristics (including anticoagulation use, platelet testing, number of devices used, sheaths, and so forth). Categoric variables were compared with χ(2) testing, and continuous variables were compared with the Student t test. Odds ratios and 95% confidence intervals were obtained by using univariate logistic regression. Multivariate logistic regression analysis was used to determine which factors were independently associated with postoperative stroke.

RESULTS

Of 793 patients with 906 aneurysms, 36 (4.5%) patients had acute ischemic stroke. Twenty-six (72.2%) strokes occurred within 30 days of treatment (median, 3.5 days; range, 0-397 days). Ten patients died, and the remaining 26 had major neurologic morbidity. Variables associated with higher odds of acute ischemic stroke on univariate analysis included male sex, hypertension, treatment of MCA aneurysms, treatment of fusiform aneurysms, treatment of giant aneurysms, and use of multiple PEDs. However, on multivariate analysis, the only one of these variables independently associated with stroke was treatment of fusiform aneurysms (OR, 2.74; 95% CI, 1.11-6.75; P = .03). Fusiform aneurysms that were associated with stroke were significantly larger than those not associated with stroke (mean, 24.5 ± 12.5 mm versus 13.6 ± 6.8 mm; P < .001).

CONCLUSIONS

Ischemic stroke following PED treatment is an uncommon-but-devastating complication. Fusiform aneurysms were the only variable independently associated with postoperative stroke.