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.

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.

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.

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.

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.

Aneurysms Associated with Brain Arteriovenous Malformations.

Brain arteriovenous malformations are frequently associated with the presence of intracranial aneurysms at a higher-than-expected incidence based on the frequency of each lesion individually. The identification of intracranial aneurysms in association with AVMs has increased due to improvement in diagnostic techniques, particularly 3D and superselective conventional angiography. Intracranial aneurysms may confer a higher risk of hemorrhage at presentation and of rehemorrhage in patients with AVMs and therefore may be associated with a more unfavorable natural history. The association of AVMs and intracranial aneurysms poses important therapeutic challenges for practicing neurosurgeons, neurologists, and neurointerventional radiologists. In this report, we review the classification and radiology of AVM-associated intracranial aneurysms and discuss their clinical significance and implications for treatment.

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.

Neurovascular Manifestations of Hereditary Hemorrhagic Telangiectasia: A Consecutive Series of 376 Patients during 15 Years.

BACKGROUND AND PURPOSE: Hereditary hemorrhagic telangiectasia is associated with a wide range of neurovascular abnormalities. The aim of this study was to characterize the spectrum of cerebrovascular lesions, including brain arteriovenous malformations, in patients with hereditary hemorrhagic telangiectasia and to study associations between brain arteriovenous malformations and demographic variables, genetic mutations, and the presence of AVMs in other organs. MATERIALS AND METHODS: Consecutive patients with definite hereditary hemorrhagic telangiectasia who underwent brain MR imaging/MRA, CTA, or DSA at our institution from 2001 to 2015 were included. All studies were re-evaluated by 2 senior neuroradiologists for the presence, characteristics, location, and number of brain arteriovenous malformations, intracranial aneurysms, and nonshunting lesions. Brain arteriovenous malformations were categorized as high-flow pial fistulas, nidus-type brain AVMs, and capillary vascular malformations and were assigned a Spetzler-Martin score. We examined the association between baseline clinical and genetic mutational status and the presence/multiplicity of brain arteriovenous malformations. RESULTS: Three hundred seventy-six patients with definite hereditary hemorrhagic telangiectasia were included. One hundred ten brain arteriovenous malformations were noted in 48 patients (12.8%), with multiple brain arteriovenous malformations in 26 patients. These included 51 nidal brain arteriovenous malformations (46.4%), 58 capillary vascular malformations (52.7%), and 1 pial arteriovenous fistula (0.9%). Five patients (10.4%) with single nidal brain arteriovenous malformation presented with hemorrhage. Of brain arteriovenous malformations, 88.9% (88/99) had a Spetzler-Martin score of ≤2. Patients with brain arteriovenous malformations were more likely to be female (75.0% versus 57.6%, P = .01) and have a family history of hereditary hemorrhagic telangiectasia (95.8% versus 84.8%, P = .04). The prevalence of brain arteriovenous malformation was 19.7% in endoglin (ENG) mutations and 12.5% in activin receptor-like kinase (1ACVRL1) mutations. CONCLUSIONS: Our study of 376 patients with hereditary hemorrhagic telangiectasia demonstrated a high prevalence of brain arteriovenous malformations. Nidal brain arteriovenous malformations and capillary vascular malformations occurred in roughly equal numbers.

Smoking Does Not Affect Occlusion Rates and Morbidity-Mortality after Pipeline Embolization for Intracranial Aneurysms.

BACKGROUND AND PURPOSE: Smoking is a major risk factor for patients with intracranial aneurysms, yet the effects of smoking on outcomes of aneurysm with flow-diverter treatment remain unknown. We studied the impact of smoking on long-term angiographic and clinical outcomes after flow-diverter treatment of intracranial aneurysms. MATERIALS AND METHODS: We retrospectively reviewed data from patients treated with the Pipeline Embolization Device and included in the International Retrospective Study of the Pipeline Embolization Device, the Pipeline for Uncoilable or Failed Aneurysms Study, and the Aneurysm Study of Pipeline in an Observational Registry. Patients were stratified according to smoking status into 3 groups: 1) never smoker, 2) current smoker, and 3) former smoker. We studied angiographic and clinical outcomes. Outcomes were compared by using χ(2) and Student t tests. A multivariate analysis was performed to determine whether smoking was independently associated with poor outcomes. RESULTS: Six hundred sixteen patients with 694 aneurysms were included. Current smokers had a smaller mean aneurysm size compared with the other 2 groups (P = .005) and lower rates of multiple Pipeline Embolization Device use (P = .015). On multivariate analysis, former smokers (OR, 1.08; 95% CI, 0.43-2.71; P = .57) and current smokers (OR, 0.70; 95% CI, 0.27-1.77; P = .38) had similar odds of long-term angiographic incomplete occlusion compared with never smokers. Former smokers (OR, 1.27; 95% CI, 0.64-2.52; P = .25) and current smokers (OR, 0.74; 95% CI, 0.37-1.46; P = .22) had similar odds of major morbidity and neurologic mortality compared with never smokers. CONCLUSIONS: These results suggest that smoking is not associated with angiographic and clinical outcomes among patients treated with the Pipeline Embolization Device. Nonetheless, patients with intracranial aneurysms should continue to be counseled about the risks of tobacco smoking.

Mucor Thrombus.

BACKGROUND: To describe a rare presentation of ischemic stroke secondary to angioinvasive mucormycosis and endovascular retrieval of mycotic thrombus with stenting of the compressed vessel. SUMMARY OF CASE: We report a case of angioinvasive mucormycosis that externally compressed and invaded the internal carotid artery causing ischemic cerebral infarction. A sample of the thrombus was obtained using a stent retriever. Subsequent pathological analysis was shown to be consistent with the diagnosis of angioinvasive mucormycosis. The thrombosed and compressed segment was recanalized with the deployment of a stent. CONCLUSIONS: The endovascular placement of an expandable stent in the setting of angioinvasive mucormycosis restored good cerebral blood flow in a proximal internal carotid artery occlusion. The patient's aphasia resolved following this intervention. Artifacts of CT angiography may result in the overestimation of acute arterial occlusions. Endovascular carotid stenting may be a palliative measure in the setting of angioinvasive rhino-cerebro-orbital mucormycosis.

Evaluation of the Angiographic Grading Scale in Aneurysms Treated with the WEB Device in 80 Rabbits: Correlation with Histologic Evaluation.

BACKGROUND AND PURPOSE: The WEB Occlusion Score has been proposed to assess angiographic outcomes for intracranial aneurysms treated with the Woven EndoBridge (WEB) device. Using a large series of experimental aneurysms treated with the WEB, we had the following objectives: 1) to compare angiographic outcomes as measured by the WEB Occlusion Scale with histologic results, and 2) to assess interobserver and intraobserver agreement of the WEB Occlusion Scale. MATERIALS AND METHODS: Intracranial aneurysms were created in 80 rabbits and treated with WEB devices. Animals were sacrificed at last follow-up for histologic evaluation. DSA was performed just after the deployment of the device and at follow-up. Four investigators independently and retrospectively graded the DSA twice according to the WEB Occlusion Scale. One histopathologist blinded to the angiographic results graded the occlusion according to a 4-point scale patterned on the WEB Occlusion Scale. Intra- and interobserver agreement were evaluated for DSA. Follow-up angiographic grading and histologic reference were compared to determine the WEB Occlusion Scale accuracy for complete (with or without recess filling) versus incomplete occlusion and adequate (complete occlusion or neck remnant) versus inadequate occlusion. RESULTS: Inter- and intraobserver weighted κ for the angiographic WEB Occlusion Scale were, respectively, 0.76 and 0.76, indicating substantial agreement. The sensitivity and specificity of the WEB Occlusion Scale for complete occlusion at follow-up compared with the histologic reference standard were, respectively, 75% and 83.3%, with an overall accuracy of 80%. Similarly, for adequate occlusion at follow-up, sensitivity was 97.7%, specificity was 64.9%, and overall accuracy was 82.5%. CONCLUSIONS: The WEB Occlusion Scale appears to be consistent, reliable, and accurate compared with a histologic reference standard.

Validity of the Meyer Scale for Assessment of Coiled Aneurysms and Aneurysm Recurrence.

BACKGROUND AND PURPOSE: Both the Meyer and Raymond scales are commonly used to report angiographic outcomes following coil embolization of intracranial aneurysms. The objectives of this study were the following: 1) to assess the interobserver agreement of the Meyer and Raymond scales, and 2) to evaluate and compare their performance in predicting major recurrence at follow-up. MATERIALS AND METHODS: A retrospective series of 120 coiled aneurysms was included. Four investigators independently graded DSA images immediately posttreatment and at follow-up according to the Meyer and Raymond scales. On follow-up DSA, readers also evaluated recurrence outcome. Interobserver agreement was assessed via the intraclass correlation coefficient. The ability of posttreatment Meyer and Raymond scales to predict major recurrence was modeled by using logistic regression and assessed by using receiver operating characteristic analysis. RESULTS: For the Meyer scale, interobserver intraclass correlation coefficients were 0.58 (95% CI, 0.46-0.68) on posttreatment and 0.78 (95% CI, 0.72-0.83) on follow-up evaluations. For the Raymond scale, interobserver intraclass correlation coefficients were 0.50 (95% CI, 0.39-0.61) and 0.69 (95% CI, 0.62-0.76), respectively, for posttreatment and follow-up. The areas under the curve for the receiver operating characteristic analyses regarding the performance to predict major recurrence at follow-up were 0.69 (95% CI, 0.60-0.79) for the Meyer and 0.70 (95% CI, 0.61-0.78) for the Raymond scale. CONCLUSIONS: The Meyer scale appears consistent and reliable with observer agreement as high or higher than that of the Raymond scale. Performance of both scales in predicting the risk of major recurrence at follow-up is adequate, with no statistical difference between the scales.

Risk Factors for Growth of Intracranial Aneurysms: A Systematic Review and Meta-Analysis.

BACKGROUND AND PURPOSE: Understanding risk factors for intracranial aneurysm growth is important for patient management. We performed a meta-analysis examining risk factors for intracranial aneurysm growth in longitudinal studies and examined the association between aneurysm growth and rupture. MATERIALS AND METHODS: We searched the literature for longitudinal studies of patients with unruptured aneurysms. We examined the associations of demographics, multiple aneurysms, prior subarachnoid hemorrhage, family history of aneurysm or subarachnoid hemorrhage, smoking, and hypertension; and aneurysm shape, size, and location with aneurysm growth. We studied the association between aneurysm growth and rupture. A meta-analysis was performed by using a random-effects model by using summary statistics from included studies. RESULTS: Twenty-one studies including 3954 patients with 4990 aneurysms with 13,294 aneurysm-years of follow-up were included. The overall proportion of growing aneurysms was 3.0% per aneurysm-year (95% CI, 2.0%-4.0%). Patient risk factors for growth included age older than 50 years (3.8% per year versus 0.9% per year, P < .01), female sex (3.2% per year versus 1.3% per year, P < .01), and smoking history (5.5% per year versus 3.5% per year, P < .01). Characteristics associated with higher growth rates included cavernous carotid artery location (14.4% per year), nonsaccular shape (14.7% per year versus 5.2% per year for saccular, P < .01), and aneurysm size (P < .01). Aneurysm growth was associated with a rupture rate of 3.1% per year compared with 0.1% per year for stable aneurysms (P < .01). CONCLUSIONS: Observational evidence provided multiple clinical and anatomic risk factors for aneurysm growth, including age older than 50 years, female sex, smoking history, and nonsaccular shape. These findings should be considered when counseling patients regarding the natural history of unruptured intracranial aneurysms.

Endovascular Treatment of Ruptured Blister-Like Aneurysms: A Systematic Review and Meta-Analysis with Focus on Deconstructive versus Reconstructive and Flow-Diverter Treatments.

BACKGROUND AND PURPOSE: Various endovascular techniques have been applied to treat blister-like aneurysms. We performed a systematic review to evaluate endovascular treatment for ruptured blister-like aneurysms. MATERIALS AND METHODS: We performed a comprehensive literature search and subgroup analyses to compare deconstructive versus reconstructive techniques and flow diversion versus other reconstructive options. RESULTS: Thirty-one studies with 265 procedures for ruptured blister-like aneurysms were included. Endovascular treatment was associated with a 72.8% (95% CI, 64.2%-81.5%) mid- to long-term occlusion rate and a 19.3% (95% CI, 13.6%-25.1%) retreatment rate. Mid- to long-term neurologic outcome was good in 76.2% (95% CI, 68.9%-8.4%) of patients. Two hundred forty procedures (90.6%) were reconstructive techniques (coiling, stent-assisted coiling, overlapped stent placement, flow diversion) and 25 treatments (9.4%) were deconstructive. Deconstructive techniques had higher rates of initial complete occlusion than reconstructive techniques (77.3% versus 33.0%, P = .0003) but a higher risk for perioperative stroke (29.1% versus 5.0%, P = .04). There was no difference in good mid- to long-term neurologic outcome between groups, with 76.2% for the reconstructive group versus 79.9% for the deconstructive group (P = .30). Of 240 reconstructive procedures, 62 (25.8%) involved flow-diverter stents, with higher rates of mid- to long-term complete occlusion than other reconstructive techniques (90.8% versus 67.9%, P = .03) and a lower rate of retreatment (6.6% versus 30.7%, P < .0001). CONCLUSIONS: Endovascular treatment of ruptured blister-like aneurysms is associated with high rates of complete occlusion and good mid- to long-term neurologic outcomes in most patients. Deconstructive techniques are associated with higher occlusion rates but a higher risk of perioperative ischemic stroke. In the reconstructive group, flow diversion carries a higher level of complete occlusion and similar clinical outcomes.

Risk Factors for Hemorrhagic Complications following Pipeline Embolization Device Treatment of Intracranial Aneurysms: Results from the International Retrospective Study of the Pipeline Embolization Device.

BACKGROUND AND PURPOSE: Spontaneous intraparenchymal hemorrhage is a dreaded complication of unknown etiology following flow-diversion treatment. Using the International Retrospective Study of the Pipeline Embolization Device registry, we studied demographic, aneurysm, and procedural characteristics associated with intraparenchymal hemorrhage following Pipeline Embolization Device treatment. MATERIALS AND METHODS: We identified patients in the International Retrospective Study of the Pipeline Embolization Device registry with intraparenchymal hemorrhage unrelated to index aneurysm rupture post-Pipeline Embolization Device treatment. The rate of intraparenchymal hemorrhage was determined by baseline demographics, comorbidities, aneurysm characteristics, and procedural characteristics (including anticoagulation use, platelet testing, number of devices used, sheaths, catheters, and guidewires). Categoric variables were compared with χ(2) testing, and continuous variables were compared with the Student t test. RESULTS: Of 793 patients with 906 aneurysms, 20 (2.5%) had intraparenchymal hemorrhage. Fifteen intraparenchymal hemorrhages (75.0%) occurred within 30 days of treatment (median, 5 days; range, 0-150 days). Nine patients with intraparenchymal hemorrhage (45.0%) died, 10 (50.0%) had major neurologic morbidity, and 1 had minor neurologic morbidity (5.0%). Intraparenchymal hemorrhage was ipsilateral to the Pipeline Embolization Device in 16 patients (80%) and contralateral in 3 patients (15.0%). Variables associated with higher odds of intraparenchymal hemorrhage included treatment of ruptured aneurysms (OR, 4.44; 95% CI, 1.65-11.94; P = .005) and the use of ≥ 3 Pipeline Embolization Devices (OR, 4.10; 95% CI, 1.34-12.58; P = .04). The Shuttle sheath was not associated with intraparenchymal hemorrhage (OR, 0.97; 95% CI, 0.38-2.45; P = .95). CONCLUSIONS: Spontaneous intraparenchymal hemorrhage following Pipeline Embolization Device treatment is a rare-but-devastating complication, with nearly all patients having morbidity or mortality. Variables associated with intraparenchymal hemorrhage included the use of multiple Pipeline Embolization Devices and treatment of ruptured aneurysms. The Shuttle, a device that was previously thought to be associated with intraparenchymal hemorrhage, was not associated with it.

Platelet Testing is Associated with Worse Clinical Outcomes for Patients Treated with the Pipeline Embolization Device.

BACKGROUND AND PURPOSE: The necessity for platelet-inhibition testing before aneurysm treatment in patients premedicated with antiplatelet agents is controversial. Using the International Retrospective Study of Pipeline Embolization Device registry, we studied complication rates in groups of patients who underwent platelet testing and those who did not undergo platelet testing to determine if these test results were associated with improved outcomes. MATERIALS AND METHODS: Patients in the International Retrospective Study of Pipeline Embolization Device registry with an unruptured aneurysm were categorized as those who underwent platelet testing before Pipeline embolization device treatment or those who did not. Complication rates were compared by using the Fisher exact or Pearson χ(2) test. Multivariate analysis was performed to determine if platelet function testing was independently associated with poor outcomes after adjusting for age, number of devices and aneurysms, aneurysm location and size, and practitioner and center volume. RESULTS: Compared with the patients who received a Pipeline embolization device without platelet testing, those who underwent platelet testing and Pipeline embolization device placement experienced higher rates of intracranial hemorrhage (0 of 187 [0.0%] vs 12 of 511 [2.3%], respectively; P = .04), neurologic morbidity (4 of 187 [2.1%] vs 42 of 511 [8.2%], respectively; P < .01), and combined neurologic morbidity and mortality (6 of 187 [3.2%] vs 45 of 511 [8.8%], respectively; P = .01). More patients in the platelet testing and Pipeline embolization device group were treated with multiple devices (227 [38.0%] vs 56 [27.8] patients, respectively; P = .01). On multivariate analysis, the group of patients who underwent platelet testing and Pipeline embolization device placement had higher odds of neurologic morbidity (OR, 3.25 [95% CI, 1.10-9.61]; P = .03). CONCLUSIONS: Platelet testing in patients who undergo Pipeline embolization device placement is associated with higher rates of morbidity. Additional prospective studies are needed to determine if and when platelet testing in these patients is appropriate.

Could Statin Use Be Associated with Reduced Recurrence Rates following Coiling in Ruptured Intracranial Aneurysms?

BACKGROUND AND PURPOSE: A number of studies have examined the role of matrix metalloproteinases in aneurysm healing following endovascular coiling. Because ruptured aneurysms are known to express higher levels of matrix metalloproteinases, we hypothesized that patients with subarachnoid hemorrhage who were on a statin at the time of coil embolization would have lower aneurysm recanalization and retreatment rates than patients not on statins. MATERIALS AND METHODS: We performed a retrospective chart review of patients who underwent intrasaccular coil embolization of ruptured intracranial aneurysms of ≤10 mm with at least 6 months of imaging follow-up. Patients were separated into 2 groups: 1) those on an oral statin medication at the time of coiling, and 2) those who were not. Outcomes studied were aneurysm recurrence and aneurysm retreatment after endovascular coiling. Student t and χ(2) tests were used for statistical significance of differences between groups. RESULTS: One hundred thirty-two patients with 132 ruptured aneurysms were included in our study. Sixteen were on statins (12.1%) and 116 were not (87.9%). The recurrence rate was 6.3% in the statin group (1/16) and 36.2% in the nonstatin group (42/107) (P = .02). Unplanned retreatment rates were 6.3% (1/16) for the statin group and 25.9% (30/116) for the nonstatin group (P = .08). CONCLUSIONS: Statins were associated with a lower rate of aneurysm recurrence following endovascular coiling of small- and medium-sized ruptured aneurysms in this small retrospective study. Further studies are needed to confirm this finding to determine whether statins can be used to reduce recurrence rates in these aneurysms.

HydroCoils Are Associated with Lower Angiographic Recurrence Rates Than Are Bare Platinum Coils in Treatment of "Difficult-to-Treat" Aneurysms: A Post Hoc Subgroup Analysis of the HELPS Trial.

BACKGROUND AND PURPOSE: The HydroCoil Endovascular Aneurysm Occlusion and Packing Study was a randomized controlled trial that compared HydroCoils to bare platinum coils. Using data from this trial, we performed a subgroup analysis of angiographic and clinical outcomes of patients with "difficult-to-treat" aneurysms, defined as irregularly shaped and/or having a dome-to-neck ratio of <1.5. MATERIALS AND METHODS: Separate subgroup analyses comparing outcomes of treatment with HydroCoils to that of bare platinum coils were performed for the following: 1) irregularly shaped aneurysms, 2) regularly shaped aneurysms, 3) aneurysms with a dome-to-neck ratio of <1.5, and 4) aneurysms with a dome-to-neck ratio of ≥1.5. For each subgroup analysis, the following outcomes were studied at the last follow-up (3-18 months): 1) any recurrence, 2) major recurrence, 3) re-treatment, and 4) an mRS score of ≤2. Multivariate logistic regression analysis was performed to determine if the HydroCoil was independently associated with improved outcomes in these subgroups. RESULTS: Among the patients with an irregularly shaped aneurysm, the HydroCoil was associated with lower major recurrence rates than the bare platinum coils (17 of 66 [26%] vs 30 of 69 [44%], respectively; P = .046). Among the patients with an aneurysm with a small dome-to-neck ratio, the HydroCoil was associated with lower major recurrence rates than the bare platinum coils (18 of 73 [24.7%] vs 32 of 76 [42.1%], respectively; P = .02). No difference in major recurrence was seen between HydroCoils and bare platinum coils for regularly shaped aneurysms (42 of 152 [27.6%] vs 52 of 162 [32.1%], respectively; P = .39) or aneurysms with a large dome-to-neck ratio (41 of 145 [28.3%] vs 50 of 155 [32.3%], respectively; P = .53). CONCLUSIONS: This unplanned post hoc subgroup analysis found that HydroCoils are associated with improved angiographic outcomes in the treatment of irregularly shaped aneurysms and aneurysms with a dome-to-neck ratio of <1.5. Because this was a post hoc analysis, these results are not reliable and absolutely should not alter clinical practice but, rather, may inform the design of future randomized controlled trials.