Safety and efficacy of dynamic catheter-directed cerebral digital subtraction angiography for diagnosis of bowhunter syndrome spectrum disorders: A systematic review of the literature

INTRODUCTION

Dynamic catheter-directed cerebral digital subtraction angiography (dcDSA) is the gold standard for diagnosing dynamic vascular occlusion syndromes such as bowhunter syndrome (BHS). Nonetheless, concerns about its safety exist and no standardized protocols have been published to date.

METHODS

We describe our methodology and insights regarding the use of dcDSA in patients with BHS. We also perform a systematic literature review to identify cases of typical and atypical presentations of BHS wherein dcDSA was utilized and report on any procedural complications related to dcDSA.

RESULTS

Our study included 104 cases wherein dcDSA was used for the diagnosis of BHS. There were 0 reported complications of dcDSA. DcDSA successfully established diagnosis in 102 of these cases. Thirty-eight cases were deemed atypical presentations of BHS. Fourteen patients endorsed symptoms during neck flexion/extension. In eight cases, there was dynamic occlusion of bilateral vertebral arteries during a single maneuver. Three patients had multiple areas of occlusion along a single vertebral artery (VA). An anomalous entry of the VA above the C6 transverse foramen was observed in four patients. One patient had VA occlusion with neutral head position and recanalization upon contralateral lateral head tilt.

CONCLUSION

Our study highlights the safety and diagnostic benefits of dcDSA in characterizing the broad spectrum of BHS pathology encountered in clinical practice. This technique offers a powerful means to evaluate changes in cerebral blood flow and cervical arterial morphology in real time, overcoming the constraints of static imaging methods. Our findings pave the way for further studies on dcDSA to enhance cross-sectional imaging methods for the characterization of BHS and other dynamic vascular occlusion syndromes.

Three-Dimensional Ultrasound Imaging of Retinoblastoma and Its Correlation With Pathology

BACKGROUND AND OBJECTIVE

Monitoring the response of retinoblastoma to globe-salvaging therapies is based on subjective assessments of changes determined by fundoscopy, ultrasound, and optical coherence tomography. Advances in organ-preserving therapies have increased the need for objective, quantitative estimates of tumor response to treatment. Primary tumor volume is a metric that can be objectively determined as a surrogate measure of treatment response.

PATIENTS AND METHODS

We evaluated the correlation of objective, quantitative estimates of tumor volume made with two-dimensional (2D) and three-dimensional (3D) ultrasound with gold standard pathological tumor volumes derived by analysis of enucleation specimens.

RESULTS

Twelve eyes in 12 patients undergoing primary enucleation were evaluated by 2D and 3D ultrasound during ophthalmic examination under anesthesia prior to enucleation. 2D- and 3D-ultra-sound measurements of tumor volume were both strongly correlated with pathological estimates of tumor volume (r = 0.69, P = 0.018; and r = 0.66, P = 0.027, respectively).

CONCLUSIONS

2D- and 3D-ultrasound measurements of retinoblastoma primary tumor volume are highly correlated with pathological estimates. 3D measurements are easy to perform with volumetric probes and consider the irregular morphology of the tumor. Further study should be undertaken to evaluate the performance of these metrics as surrogate markers of tumor response to treatment. [Ophthalmic Surg Lasers Imaging Retina 2024;55:136-140.].

Microvascular flow ultrasound imaging for retinoblastoma

PURPOSE

To present the results of a pilot study of microvascular flow imaging (MFI) in characterizing tumor vasculature of retinoblastoma.

METHODS

The medical records of consecutive patients with retinoblastoma presenting at our institution between July 2019 and June 2022 that were imaged using MFI were reviewed retroactively. Each patient underwent diagnostic evaluation according to standard of care by examination under anesthesia with fluorescein angiography and ocular ultrasound imaging, including color Doppler and MFI.

RESULTS

Thirteen eyes of 10 patients with retinoblastoma were included. MFI showed a prominent feeder vessel in 8 eyes, basket vasculature in 6 eyes and tumor bed vascularity in 10 eyes. MFI showed a more extensive vascular branching pattern that was not visible on color Doppler and fluorescein angiography in all eyes.

CONCLUSIONS

MFI of retinoblastoma patients could add information about tumor vascularity not detectable by color Doppler or fluorescein angiography. Further study is needed to determine whether this information could be used to predict prognosis for ocular salvage and tumor response to treatment.

Reversal of Cerebral Arteriopathy Post-Hematopoietic Stem Cell Transplant for Sickle Cell Disease

Sickle cell disease (SCD) is a chronic hematologic disorder which causes progressive cerebral arteriopathy beginning in childhood. As a result, arterial ischemic stroke is a major cause of morbidity and mortality in SCD, and SCD is a leading cause of childhood stroke worldwide. Allogenic hematopoietic stem cell transplant (HSCT) may be curative for individuals with SCD. Long-term outcomes and effects are currently being studied. In this report, we describe a child with SCD who presented with arterial ischemic stroke at 6 years of age and was found to have a severe form of cerebral large vessel arteriopathy by catheter-directed angiography. The patient initially underwent revascularization surgery by indirect superficial temporal artery to middle cerebral artery bypass, and 1 year later, he underwent curative HSCT. Approximately 3 years after HSCT, repeat catheter-directed angiography revealed a striking reversal of cerebral large vessel arteriopathy. This article reveals a previously unrecognized and potentially beneficial effect of HSCT that may ameliorate cerebral large vessel arteriopathy and improve cerebrovascular health for children with SCD.

Changes in autonomic function and cerebral and somatic oxygenation with arterial flow pulsatility for children requiring veno-arterial extracorporeal membrane oxygenation

Background

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) carries variability in arterial flow pulsatility (AFP).

Research question

What changes in cerebral and somatic oxygenation, hemodynamics, and autonomic function are associated with AFP during VA-ECMO?

Methods

This is a prospective study of children on VA-ECMO undergoing neuromonitoring. AFP was quantified by arterial blood pressure pulse amplitude and subcategorized: no pulsatility (<1 mmHg), minimal pulsatility (1 to <5 mmHg), moderate pulsatility (5 to <15 mmHg) and high pulsatility (≥15 mmHg). CVPR was assessed using the cerebral oximetry index (COx). Cerebral and somatic oxygenation was assessed using cerebral regional oximetry (rSO2) or peripheral oxygen saturation (SpO2). Autonomic function was assessed using baroreflex sensitivity (BRs), low-frequency high-frequency (LF/HF) ratio and standard deviation of heart rate R-R intervals (HRsd). Differences were assessed across AFP categories using linear mixed effects models with Tukey pairwise comparisons. Univariate logistic regression was used to explore risk of AFP with brain injuries.

Results

Among fifty-three children, comparisons of moderate to high pulsatility were associated with reductions in rSO2 (p < 0.001), SpO 2 (p = 0.005), LF/HF ratio (p = 0.028) and an increase in HRsd (p < 0.001). Reductions in BRs were observed across comparisons of none to minimal (P < 0.001) and minimal to moderate pulsatility (p = 0.004). Comparisons of no to low pulsatility were associated with reductions in BRs (p < 0.001) and ABP (p < 0.001) with increases in SpO2 (p < 0.001) and HR (p < 0.001). Arterial ischemic stroke was associated with higher pulsatility (p = 0.0384).

Conclusion

During VA-ECMO support, changes toward high AFP are associated with autonomic dysregulation and compromised cerebral and somatic tissue oxygenation.

Mechanical disorders of the cervicocerebral circulation in children and young adults

Mechanical disorders of the cervicocerebral circulation (MDCC) are conditions in which neurological symptoms result from a disturbance of cerebral blood flow attributable to external mechanical forces exerted on extracranial blood vessels by adjacent musculoskeletal structures during head movement that is presumably within a physiological range. The disease spectrum includes bow hunter's syndrome, carotid-type Eagle syndrome, and various dynamic venous compression syndromes. These conditions have distinct phenotypes in children which differ from those expressed in older adults. In contemporary practice, recognition and diagnostic evaluation is the domain of the neuroendovascular specialist. The diagnostic evaluation of MDCC involves significant technical nuance that can be critical to directing appropriate management, particularly in children. This report aims to provide a comprehensive overview of the pathophysiology, anatomical patterns, diagnosis, and treatment for the full spectrum of MDCC that is commonly encountered in clinical practice.

Cerebral Arterial Growth in Childhood

BACKGROUND

Improved understanding of cerebral arterial growth in children may lead to advances in the diagnosis and treatment of pediatric cerebrovascular disease. We correlated cross-sectional diameters of major cerebral arterial structures with age, sex, head circumference, weight, and height in children without cerebrovascular disease.

METHODS

Children with normal brain magnetic resonance imaging (MRI) were retrospectively identified and stratified into 23 age cohorts from birth to age 18 years. Absence of vascular disease was verified by medical record review. Demographic and biometric data were obtained from medical records. Intracranial arterial diameter (IAD) was measured on T2-weighted fast spin echo brain MRI of vertebral, basilar, internal carotid artery, and circle of Willis arterial segments.

RESULTS

A total of 307 subjects are included in the analysis, including 5833 vessel segments (mean age 8.4 years, 53% female). Indications for imaging were headache (73%), seizure (26%) and concussion (1%). IAD rapidly increased during the first year of life (mean growth velocity 0.064 to 0.213 mm/month) and then plateaued or slightly decreased between age one and 18 years (mean growth velocity -0.002 to 0.003 mm/month). Multivariable analysis shows strongest correlation with head circumference as a predictor of IAD. Weaker correlations are associated with weight and age. Height and sex are not well correlated with IAD.

CONCLUSIONS

Intracranial arteries grow rapidly during the first year of life and then sharply plateau or slightly decrease in luminal diameter between infancy and early adulthood. IAD is more closely correlated with head circumference than age.

Arterioectatic Spinal Angiopathy of Childhood: Clinical, Imaging, Laboratory, Histologic, and Genetic Description of a Novel CNS Vascular Pathology

Pediatric patients with myelopathy expressing intradural spinal vascular ectasia without arteriovenous shunting were studied at four tertiary referral neuropediatric centers. Patients were identified by retrospective review of institutional records and excluded if spinal vascular pathology could be classified into a previously described category of spinal vascular malformation. Four patients meeting the study criteria were enrolled in the study. Clinical, magnetic resonance imaging, catheter-directed angiography, laboratory, histological and genetic data were analyzed to characterize the disease process and elucidate underlying pathomechanisms. Our study revealed a highly lethal, progressive multi-segmental myelopathy associated with a unique form of non-inflammatory spinal angiopathy featuring diffuse enlargement and tortuosity of spinal cord arteries, spinal cord hyperemia, and spinal cord edema (Arterioectatic Spinal Angiopathy of Childhood). The condition was shown to mimic venous congestive myelopathy associated with pediatric spinal cord arteriovenous shunts on MRI but to have distinct pathognomonic findings on catheter-directed angiography. Clinicopathological, genetic, and neuroimaging features, which are described in detail, closely overlap with those of mitochondrial disease.

Multimodal Assessment of Cerebral Autoregulation and Autonomic Function After Pediatric Cerebral Arteriovenous Malformation Rupture

BACKGROUND

Management after cerebral arteriovenous malformation (AVM) rupture aims toward preventing hemorrhagic expansion while maintaining cerebral perfusion to avoid secondary injury. We investigated associations of model-based indices of cerebral autoregulation (CA) and autonomic function (AF) with outcomes after pediatric cerebral AVM rupture.

METHODS

Multimodal neurologic monitoring data from the initial 3 days after cerebral AVM rupture were retrospectively analyzed in children (< 18 years). AF indices included standard deviation of heart rate (HRsd), root-mean-square of successive differences in heart rate (HRrmssd), low-high frequency ratio (LHF), and baroreflex sensitivity (BRS). CA indices include pressure reactivity index (PRx), wavelet pressure reactivity indices (wPRx and wPRx-thr), pulse amplitude index (PAx), and correlation coefficient between intracranial pressure pulse amplitude and cerebral perfusion pressure (RAC). Percent time of cerebral perfusion pressure (CPP) below lower limits of autoregulation (LLA) was also computed for each CA index. Primary outcomes were determined using Pediatric Glasgow Outcome Score Extended-Pediatrics (GOSE-PEDs) at 12 months and acquired epilepsy. Association of biomarkers with outcomes was investigated using linear regression, Wilcoxon signed-rank, or Chi-square.

RESULTS

Fourteen children were analyzed. Lower AF indices were associated with poor outcomes (BRS [p = 0.04], HRsd [p = 0.04], and HRrmssd [p = 0.00]; and acquired epilepsy (LHF [p = 0.027]). Higher CA indices were associated with poor outcomes (PRx [p = 0.00], wPRx [p = 0.00], and wPRx-thr [p = 0.01]), and acquired epilepsy (PRx [p = 0.02] and wPRx [p = 0.00]). Increased time below LLA was associated with poor outcome (percent time below LLA based on PRx [p = 0.00], PAx [p = 0.04], wPRx-thr [p = 0.03], and RAC [p = 0.01]; and acquired epilepsy (PRx [p = 0.00], PAx [p = 0.00], wPRx-thr [p = 0.03], and RAC [p = 0.01]).

CONCLUSIONS

After pediatric cerebral AVM rupture, poor outcomes are associated with AF and CA when applying various neurophysiologic model-based indices. Prospective work is needed to assess these indices of CA and AF in clinical decision support.

Arteritis and Large Vessel Occlusive Strokes in Children After COVID-19 Infection

We describe 2 previously healthy children who suffered disabling arterial ischemic strokes because of acute intracranial large vessel occlusion within 3 to 4 weeks of coronavirus disease 2019 (COVID-19) infection. Both children presented from communities with high COVID-19 case rates in the Southwest United States. An 8-year-old American Indian girl experienced severe iron deficiency anemia requiring blood transfusion and presented with bilateral middle cerebral artery (MCA) distribution strokes 3 weeks later. She underwent emergent mechanical thrombectomy of the left MCA with successful clot retrieval but experienced reocclusion of that artery 5 hours after intervention. She also had evidence of cerebral arteritis on catheter angiography and vessel wall imaging, and clot pathology revealed recently formed, unorganized platelet- and fibrin-rich thrombus with sparse clusters of erythrocytes, degenerated histiocytes, few eosinophils, and rare neutrophils. A 16-year old African American boy demonstrated evidence of arteritis on brain magnetic resonance angiography and serological markers of cardiac and renal injury accompanied by positive lupus anticoagulant antibodies. The children described in this report express clinical features inconsistent with focal cerebral arteriopathy, including elevated markers of systemic inflammation in both bilateral MCA strokes in one case and multiple organ system dysfunction in the other case. Neither patient fulfilled criteria for multisystem inflammatory syndrome in children, given absence of fever. These cases illustrate that systemic postinfectious arteritis with cerebrovascular involvement may complicate COVID-19 infection in previously healthy school-aged children, and their presentations may overlap but not fulfill criteria for multisystem inflammatory syndrome in children or focal cerebral arteriopathy.

Correlation of Technical and Adjunctive Factors with Quantitative Tumor Reduction in Children Undergoing Selective Ophthalmic Artery Infusion Chemotherapy for Retinoblastoma

BACKGROUND AND PURPOSE

Selective ophthalmic artery infusion chemotherapy has improved ocular outcomes in children with retinoblastoma. Our aim was to correlate quantitative tumor reduction and dichotomous therapeutic response with technical and adjunctive factors during selective ophthalmic artery infusion chemotherapy for retinoblastoma. An understanding of such factors may improve therapeutic efficacy.

MATERIALS AND METHODS

All patients with retinoblastoma treated by selective ophthalmic artery infusion chemotherapy at a single center during a 9-year period were reviewed. Only first-cycle treatments for previously untreated eyes were studied. Adjunctive factors (intra-arterial verapamil, intranasal oxymetazoline external carotid balloon occlusion) and technical factors (chemotherapy infusion time, fluoroscopy time) were documented by medical record review. Quantitative tumor reduction was determined by blinded comparison of retinal imaging acquired during examination under anesthesia before and 3-4 weeks after treatment. The dichotomous therapeutic response was classified according to quantitative tumor reduction as satisfactory (≥ 50%) or poor (<50%).

RESULTS

Twenty-one eyes met the inclusion criteria. Patients ranged from 2 to 59 months of age. Adjuncts included intra-arterial verapamil in 15, intranasal oxymetazoline in 14, and external carotid balloon occlusion in 14. Quantitative tumor reduction ranged from 15% to 95%. Six showed poor dichotomous therapeutic response. A satisfactory dichotomous therapeutic response was correlated with intra-arterial verapamil (P = .03) in the aggregate cohort and in a subgroup undergoing treatment with single-agent melphalan at a dose of <5 mg (P = .02). In the latter, higher average quantitative tumor reduction correlated with intra-arterial verapamil (P < .01).

CONCLUSIONS

Intra-arterial verapamil during selective ophthalmic artery infusion chemotherapy is correlated with an improved therapeutic response, particularly when treating with lower doses of single-agent melphalan.

Abstract TMP113: Non-invasive Estimate of Intracranial Arterial Luminal Diameter in Children

Background: Growth of the intracranial arteries facilitates the rapid increase in cerebral growth in the first 2 decades of life. In the age of cerebral endovascular treatment, many questions arise in the pediatric cohort regarding the safety and efficacy of these therapeutic approaches. Small arterial diameter may influence treatment selection in the very young, but to date little normative data is available to define vascular growth in infants and children.

Methods: Subjects in this single-institution, retrospective cohort study were identified by MRI brain imaging keyword query as “normal” with age 0-18 years old at the time of the study. Medical records were reviewed to capture weight, length, and head circumference and exclude cerebrovascular or connective tissue disease risk factors. MRI T2-weighted images were measured to calculate the head circumference and arterial diameter in axial and coronal planes. A growth curve was created from the head circumferences and intracranial artery diameters to compare luminal caliber to age, sex and recorded growth parameters.

Results: 317 subjects (170 female, 147 male) are included in the analysis. Luminal diameter was observed to increase rapidly in all arterial segments over the first 3 years of life. Compared to weight and length, head circumference most closely correlated with arterial size. Head circumference growth is most rapid during the first 3 years, tracking closely with the rate of luminal growth. An example relationship between arterial diameter and head circumference is shown in Figure 1.

Conclusions: This is the largest cohort of cerebral arterial luminal growth in childhood. We show that arterial diameter can be measured non-invasively on MRI brain and correlated to routinely measured growth parameters. A better understanding of normal arterial growth is essential to our treatment of cerebrovascular disease in children.

Compatibility of Melphalan in Iodinated Contrast Media

Melphalan is used in selective ophthalmic artery infusion chemotherapy. In the procedure to catheterize the ophthalmic artery in selective ophthalmic artery infusion chemotherapy, the microcatheter is usually filled with an iodinated contrast medium. It is not known whether mixing of iodinated contrast medium with melphalan solutions promotes precipitation of melphalan during selective ophthalmic artery infusion chemotherapy. The objective of the present study was to examine the compatibility of melphalan and iodinated contrast medium. In the experiments, melphalan solutions were prepared with and without iodinated contrast medium (iohexol 300 mg Iodine/mL or ioversol 74%). Melphalan solution of clinically relevant concentration (0.45 mg/mL) in the absence of iodinated contrast medium was evaluated as a reference. The 0.45-mg/mL melphalan solution was diluted with iodinated contrast medium at 1:9 and 1:1 ratios to form solutions comprising iodinated contrast medium at 10% or 50% (v/v), and each was evaluated. The formation of particles was examined using filtration (pore size 0.45 µm) followed by high-performance liquid chromatography at four quarterly time intervals (15 min, 30 min, 45 min, and 60 min) over a 1-hour period after solution preparation. High-performance liquid chromatography analysis of microfiltered solutions did not reveal evidence of melphalan crystal formation over a 60-minute period for the solutions studied. The filtration studies suggest that mixing of the iodinated contrast medium with melphalan solutions does not result in significant melphalan precipitation.

Survey of practice patterns and preparedness for endovascular therapy in acute pediatric stroke

PURPOSE

Endovascular therapy benefits selected adults with acute stroke while data are lacking for children. The purpose of this study was to assess physician practice and institutional preparedness for endovascular therapy in pediatric stroke.

METHODS

A link to an anonymous online survey was sent to members of the International Pediatric Stroke Study (IPSS) group about physician experience with endovascular therapy, likelihood of treatment for provided clinical vignettes, and institutional readiness for the delivery of endovascular therapy to children.

RESULTS

Thirty-one pediatric physicians with a mean of 11 years (SD 7.1) of experience responded. All but two would consider endovascular therapy in a child, and 20 (64.5%) had recommended endovascular therapy for a child in the preceding year. Most (n = 19, 67.9%) did not commit to an age minimum for endovascular therapy. Sixteen (57.1%) would consider treatment up to 24 h after symptom onset with 19 (67.9%) respondents reporting that their practice changed after the 2018 American Heart Association guidelines extended the time window for endovascular therapy in adults. Seventeen (60.7%) preferred imaging that included perfusion in children presenting beyond 6 h. Nineteen (70.4%) had institutional endovascular therapy criteria. Physicians in larger pediatric groups had more "likely to treat" responses on the clinical vignettes than physicians working in smaller groups (11.7 vs. 6.1, p < 0.05).

CONCLUSION

Pediatric stroke physicians are largely willing to consider endovascular therapy with most changing their practice according to adult guidelines, though experience and selection criteria varied. These findings may help to inform consensus guidelines and clinical trial development.

The Complex Spine in Children with Spinal Muscular Atrophy: The Transforaminal Approach-A Transformative Technique

BACKGROUND AND PURPOSE

Spinal muscular atrophy, a genetic disease resulting in loss of motor function, presents from in utero to adulthood. Depending on progression and secondary scoliosis, spinal stabilization may be necessary. When planning intrathecal access in these patients, spinal anatomy is the most important factor. Therefore, when planning intrathecal nusinersen injections, we subdivided patients with spinal muscular atrophy into simple-versus-complex spine subgroups. Our purpose was to present our experience with our first 42 transforaminal intrathecal nusinersen injections.

MATERIALS AND METHODS

We reviewed 31 consecutive patients with spinal muscular atrophy types 1-3 who presented for intrathecal nusinersen injections from March 2017 to September 2018. Nine children had complex spines (ie, spinal instrumentation and/or fusion) and required preprocedural imaging for route planning for subarachnoid space access via transforaminal or cervical approaches.

RESULTS

A total of 164 intrathecal nusinersen injections were performed in 31 children 4-226 months of age, with 100% technical success in accessing the subarachnoid space. Nine patients with complex spinal anatomy underwent 45 intrathecal nusinersen injections; 42 of 45 procedures were performed via a transforaminal approach with the remaining 3 via cervical techniques. There were no complications.

CONCLUSIONS

Our initial experience has resulted in a protocol-driven approach based on simple or complex spinal anatomy. Patients with simple spines do not need preprocedural imaging or imaging-guided intrathecal nusinersen injections. In contrast, the complex spine subgroup requires preprocedural imaging for route planning and imaging guidance for therapy, with the primary approach being the transforaminal approach for intrathecal nusinersen injections.

Percutaneous closure of right coronary to superior vena cava fistula

Coronary artery to superior vena cava (SVC) fistula is a very rare congenital anomaly of the heart. It typically follows the course of sinoatrial-nodal branch. It can originate from the right coronary or circumflex artery. In the majority of cases, it terminates in the SVC close to the right atrium junction. Only five cases were treated in literature successfully through a transcatheter approach. We present a case with a symptomatic right coronary artery to SVC fistula treated with a unique percutaneous embolization using a guidewire loop/balloon occlusion technique. Controlled access and embolization of the fistula was achieved by through-and-through guidewire access across the coronary fistula from the arterial groin access to the venous groin access with balloon occlusion of the coronary artery fistula while detachable coils were positioned.

Endovascular thrombectomy in pediatric patients with large vessel occlusion

Background

Pediatric acute ischemic stroke with underlying large vessel occlusion is a rare disease with significant morbidity and mortality. There is a paucity of data about the safety and outcomes of endovascular thrombectomy in these cases, especially with modern devices.

Methods

We conducted a retrospective review of all pediatric stroke patients who underwent endovascular thrombectomy in nine US tertiary centers between 2008 and 2017.

Results

Nineteen patients (63.2% male) with a mean (SD) age of 10.9(6) years and weight 44.6 (30.8) kg were included. Mean (SD) NIH Stroke Scale (NIHSS) score at presentation was 13.9 (5.7). CT-based assessment was obtained in 88.2% of the patients and 58.8% of the patients had perfusion-based assessment. All procedures were performed via the transfemoral approach. The first-pass device was stentriever in 52.6% of cases and aspiration in 36.8%. Successful revascularization was achieved in 89.5% of the patients after a mean (SD) of 2.2 (1.5) passes, with a mean (SD) groin puncture to recanalization time of 48.7 (37.3) min (median 41.5). The mean (SD) reduction in NIHSS from admission to discharge was 10.2 (6.2). A good neurological outcome was achieved in 89.5% of the patients. One patient had post-revascularization seizure, but no other procedural complications or mortality occurred.

Conclusions

Endovascular thrombectomy is safe and feasible in selected pediatric patients. Technical and neurological outcomes were comparable to adult literature with no safety concerns with the use of standard adult devices in patients as young as 18 months. This large series adds to the growing literature but further studies are warranted.

Quantitative Arterial Tortuosity Suggests Arteriopathy in Children With Cryptogenic Stroke

BACKGROUND AND PURPOSE

Quantitative arterial tortuosity (QAT) is a ratio of vessel length between 2 points to the shortest linear distance between same points. QAT has been reported as an imaging biomarker of arteriopathy in pediatric arterial ischemic stroke (AIS) because of dissection and transient cerebral arteriopathy. We sought to determine whether QAT abnormalities are present in other subtypes of pediatric AIS.

METHODS

Children with AIS-absent conventional biomarkers of arteriopathy and case-controls who underwent magnetic resonance angiography were classified by stroke mechanism. The primary study population consisted of cryptogenic AIS cases. AIS with bow hunter physiology and cardiogenic emboli were also evaluated. AIS because of nontraumatic dissection served as positive controls. Patients without vascular risk factors served as negative controls. Segmental QAT of cervicocerebral arteries were measured using automated image processing and differences between groups analyzed.

RESULTS

In negative controls, QAT showed significant age-related variability for most arterial segments. Positive controls showed significantly increased QAT of the distal extracranial vertebral arteries (VAs) and decreased QAT of the intracranial VA relative to negative controls. Cryptogenic stroke and bow hunter physiology cases were similar to positive controls showing increased QAT of the distal extracranial VA and decreased QAT of the intracranial VA relative to negative controls. Cardioembolic stroke cases were similar to negative controls showing decreased QAT of the distal extracranial VA and increased QAT of the intracranial VA relative to positive controls.

CONCLUSIONS

Pediatric cryptogenic stroke is frequently associated with cervicocerebral arteriopathies expressing altered QAT. QAT may be a diagnostic biomarker of arteriopathy in pediatric AIS.

Facial Palsy Following Embolization of a Juvenile Nasopharyngeal Angiofibroma

Objectives:

To describe a case of the rare complication of facial palsy following preoperative embolization of a juvenile nasopharyngeal angiofibroma (JNA). To illustrate the vascular supply to the facial nerve and as a result, highlight the etiology of the facial nerve palsy.

Methods:

The angiography and magnetic resonance (MR) imaging of a case of facial palsy following preoperative embolization of a JNA is reviewed.

Results:

A 13-year-old male developed left-sided facial palsy following preoperative embolization of a left-sided JNA. Evaluation of MR imaging studies and retrospective review of the angiographic data suggested errant embolization of particles into the petrosquamosal branch of the middle meningeal artery (MMA), a branch of the internal maxillary artery (IMA), through collateral vasculature. The petrosquamosal branch of the MMA is the predominant blood supply to the facial nerve in the facial canal. The facial palsy resolved since complete infarction of the nerve was likely prevented by collateral blood supply from the stylomastoid artery.

Conclusions:

Facial palsy is a potential complication of embolization of the IMA, a branch of the external carotid artery (ECA). This is secondary to ischemia of the facial nerve due to embolization of its vascular supply. Clinicians should be aware of this potential complication and counsel patients accordingly prior to embolization for JNA.

Abstract WMP32: Adaptive and Maladaptive Remodeling in Flow Loaded Rat Cerebral Arteries: Potential Significance to Pathogenesis of Cerebral Aneurysms

Background and purpose: In animal models, flow loading is a necessary and sufficient hemodynamic factor to express the cerebral aneurysm (CA) phenotype. Promotional biological factors may include variant forms of the adaptive response to flow loading. Using a rat model, this study characterizes molecular events that comprise cerebral arterial responses to flow loading and reveals their significance in relation to the CA phenotype.

Methods: 32 rats underwent bilateral common carotid artery ligation (BCL) (n=16) or sham surgery (SS)(n=16). Nineteen days later, vertebrobasilar arteries were harvested, histologically examined and analyzed for mRNA and protein expression. Flow (shear) induced changes in mRNA expression, protein expression and histology were determined by comparing BCL to SS rats. Differences between aneurysm-prone (Long Evans, LE) and resistant (Brown Norway, BN) strains were evaluated.

Results: Basilar artery medial thickness/luminal diameter ratio was significantly reduced in BCL rats, without significant differences between LE (2.02 fold) and BN (1.94 fold) rats. BCL significantly altered basilar artery expression of mRNA and proteins that modulate wall structure and function but had no effect on blood pressure. Eight genes showed similarly large flow induced expression changes in LE and BN rats (TyrRS, Mfge8, Galnt13, GABRP, Pp1r1a, Dpt_predicted, Cd34_predicted, ApoE). Twenty six shear responsive genes showed significant differences in shear induced expression between LE and BN rats. The Cthrc1, Gsta3, Tgfb3, Ldha, Myo1d, Ermn, PTHrp, Rgs16 and TRCCP genes showed the strongest shear responsive expression, and the largest difference in shear responsive expression between LE and BN rats.

Conclusions: Our study reveals specific molecular biological responses involved in flow induced expansive remodeling of cerebral arteries. A group of 9 strongly shear responsive genes showed major differences in flow induced expression between LE and BN rats and are implicated as having important roles in maladaptive remodeling associated with the CA phenotype.

Abstract TMP101: Magnetic Resonance Quantitative Arterial Tortuosity Reveals Evidence of Otherwise Occult Arteriopathy in Pediatric Patients With Cryptogenic Arterial Ischemic Stroke

Background and Purpose: Quantitative arterial tortuosity (QAT) has been reported as an imaging biomarker of arteriopathy in pediatric arterial ischemic stroke (AIS) due to dissection and transient cerebral arteriopathy. We sought to determine if QAT abnormalities are present in cryptogenic pediatric AIS patients.

Methods: Children with non-cardiogenic non-traumatic AIS and normal case controls who underwent MRA of the head and/or neck were identified by retrospective electronic medical record review. Patients with pre-existing clinical risk factors for AIS were excluded. The remaining cases were classified according to stroke subtype. The study population consisted of cryptogenic stroke cases. Patients with AIS due to spontaneous dissection were compared as positive case controls. Patients considered to have Bow Hunter’s Physiology (BHP), and normal case controls were also compared. QAT indices of 5 cervicocerebral arterial segments were measured in all patients using automated image processing software, and differences between groups were analyzed.

Results: In normal children, QAT of the cervicocerebral arteries showed significant age-related variability, but no sex-related differences. In pediatric patients with cryptogenic stroke, QAT indices of the cervicocerebral arteries were significantly different relative to normal case controls (p<0.05), and similar to those measured in positive case controls with spontaneous dissection. The cervicocerebral QAT indices of pediatric AIS patients with BHP were not significantly different than those measured in normal controls.

Conclusions: QAT is a specific and independent biomarker of arteriopathy in otherwise cryptogenic pediatric AIS, even when conventional clinical or imaging biomarkers of arteriopathy are absent. QAT shows promise as an independent diagnostic criterion for arteriopathy in children with AIS.

Abstract WP387: Diagnosis and Surgical Management of Rotational Vertebral Artery Occlusion in Children

Background: Rotational vertebral artery occlusion (RVAO) is associated with significant posterior circulation morbidity, recurrence, and lacks evidenced based treatment recommendations. Upper cervical spine abnormalities, lack of traumatic history, and dynamic vessel imaging aid in diagnosis and treatment options. Here, we evaluate our cohort of children with RVAO for associated musculoskeletal, angiographic, and arterial tortuosity factors in light of management strategies and outcomes.

Methods: Five pediatric patients with RVAO were evaluated with dynamic arterial compression with either CT based angiography or digital subtraction angiography. Solitary factors such as ponticulous posticus, hypermobility comorbidities, 3D-print models and arterial tortuosity index were examined in relation to management strategies.

Results: Musculoskeletal abnormalities were associated in all cases presenting with evidence of dynamic angiographic compression. Not all cases had evidence angiographic compression. A mild elevation in arterial tortuosity index was observed. All five patients were managed with treatment approaches including antiplatelet/coagulation therapies, vertebral artery decompression, and/or posterior cervical fusion.

Conclusion: Treatment strategies relied on identifiable compression factors associated with the level of vertebral artery dissection. In children, upper cervical bony abnormalities and dynamic compression at the VA3 level are common to RVAO diagnosis. Further examination of arterial tortuosity as an index in understanding the susceptibility of children towards RVAO is required.

Predicting symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage with an artificial neural network in a pediatric population

PURPOSE

Artificial neural networks (ANN) are increasingly applied to complex medical problem solving algorithms because their outcome prediction performance is superior to existing multiple regression models. ANN can successfully identify symptomatic cerebral vasospasm (SCV) in adults presenting after aneurysmal subarachnoid hemorrhage (aSAH). Although SCV is unusual in children with aSAH, the clinical consequences are severe. Consequently, reliable tools to predict patients at greatest risk for SCV may have significant value. We applied ANN modeling to a consecutive cohort of pediatric aSAH cases to assess its ability to predict SCV.

METHODS

A retrospective chart review was conducted to identify patients < 21 years of age who presented with spontaneously ruptured, non-traumatic, non-mycotic, non-flow-related intracranial arterial aneurysms to our institution between January 2002 and January 2015. Demographics, clinical, radiographic, and outcome data were analyzed using an adapted ANN model using learned value nodes from the adult aneurysmal SAH dataset previously reported. The strength of the ANN prediction was measured between - 1 and 1 with - 1 representing no likelihood of SCV and 1 representing high likelihood of SCV.

RESULTS

Sixteen patients met study inclusion criteria. The median age for aSAH patients was 15 years. Ten underwent surgical clipping and 6 underwent endovascular coiling for definitive treatment. One patient experienced SCV and 15 did not. The ANN applied here was able to accurately predict all 16 outcomes. The mean strength of prediction for those who did not exhibit SCV was - 0.86. The strength for the one patient who did exhibit SCV was 0.93.

CONCLUSIONS

Adult-derived aneurysmal SAH value nodes can be applied to a simple AAN model to accurately predict SCV in children presenting with aSAH. Further work is needed to determine if ANN models can prospectively predict SCV in the pediatric aSAH population in toto; adapted to include mycotic, traumatic, and flow-related origins as well.

Abstract TP217: Intra-arterial Verapamil Can Help Differentiate Reversible From Non-reversible Vasculopathy

Introduction: Cerebral angiography (DSA) is commonly used to characterize small vessel vasculopathy, yet it is difficult to establish etiology by angiographic patterns alone.

Hypothesis: Responsiveness to intra-arterial verapamil (IA-V) can help differentiate etiology of small vessel vasculopathy by characterizing it as reversible or non-reversible.

Methods: We performed a retrospective analysis from 2013-15 of patients referred for DSA to evaluate cerebral vasculopathy. We characterized symptoms, radiographic findings, angiographic pattern and responsiveness to IA-V, if given, as well as biopsy and follow-up angiography.

Results: Thirty-three patients were identified (70% female; mean age 47.7). Presenting symptoms were headache (48%), focal neurologic deficit (45%), cognitive impairment (30%) and seizure (18%). Three patients presented in the post-partum period. Radiographic findings included infarct (42%), cortical subarachnoid hemorrhage (33%) and cerebral edema (3%). Arteriopathy was present on DSA in 19 of 33 patients (58%). Twelve patients had smooth segmental narrowing, 6 had irregular narrowing, 1 had diffuse narrowing. IA-V was administered in 12 of the 19 patients with arteriopathy (63%), including 9 of 12 with smooth segmental, 2 of 6 with irregular, and the patient with diffuse narrowing. Of 9 patients with smooth segment narrowing that received IA-V, 8 exhibited a vasodilatory response (89%). In 1 of these patients, superficial temporal artery biopsy was normal. Follow-up DSA was performed in 4 of the 8 patients with verapamil-responsive arteriopathy at a median time of 86 days. All 4 had angiographic resolution of their arteriopathy, consistent with reversible cerebral vasoconstriction syndrome. The 3 patients with irregular or diffuse narrowing who received IA-V did not exhibit vasodilatory response or have follow-up angiography. In 3 patients with irregular narrowing, brain biopsy was performed; 1 revealed CNS vasculitis, 2 were normal, consistent with atherosclerosis.

Conclusion: Our series is consistent with reports of patients with reversible vasculopathy exhibiting a response to IA vasodilators. Response to IA-V may better characterize small vessel vasculopathy than angiographic pattern alone.

Abstract TP2: Heparin Use Across Major Endovascular Trials

Introduction: At present date, 14 randomized endovascular trials for acute ischemic stroke have been published with more recent trials demonstrating a benefit of endovascular therapy. Heparin use during the endovascular procedure is a potential confounder of patient outcome. We sought to describe and highlight differences in the heparin protocols of the major endovascular trials.

Hypothesis: We hypothesized that heparin protocols would differ among endovascular stroke trials.

Methods: We reviewed the heparin protocol from the methods section of 14 endovascular trials for acute ischemic stroke. In studies where the protocol was not included in the methods section or the appendix of a manuscript, the principal investigator of the trial was contacted to provide insight into the use of heparin during the study.

Results: No two of the major endovascular stroke trials used the same heparin protocol. Table 1 details the variability in the protocols. In cases where heparin dosing was not discussed, we left the study “N/A” in the table.

Conclusion: Although numerous endovascular ischemic stroke trials have been conducted, heparin use and its documentation during the procedure have varied greatly over the past 20 years. Heparin, an anticoagulant, could contribute to either increased bleeding or improved clot removal and maintenance of recanalization. Future studies of the role of adjunctive antithrombotic therapy during endovascular therapy are needed, and heparin use in these protocols should be specifically detailed and ideally standardized.

Abstract T MP6: The Effect of Proximal Arterial Stenosis on Outcomes Following Interventional Therapy for Acute Ischemic Stroke in the IMS-III Trial

Introduction: In patients undergoing interventional treatment for acute ischemic stroke (AIS), arterial stenosis proximal to the intracranial arterial occlusive lesion (AOL) may decrease the probability of technical success and result in worse outcomes. We examined the impact of proximal arterial stenosis in the Interventional Management of Stroke (IMS)-III trial.

Hypothesis: Arterial stenosis proximal to the intracranial AOL impedes successful interventional therapy for AIS resulting in worse outcomes.

Methods: A total of 369 patients receiving combination intra-arterial (IA) and intravenous (IV) therapy for anterior circulation AIS in the IMS-III trial were categorized according to the degree of Internal Carotid Artery (ICA) stenosis proximal to the index AOL, as determined by immediate pretreatment digital subtraction angiography. Patients with severe stenosis or occlusion (≥70%, n=37) were compared to patients without severe stenosis (<70%, n=332). Modified Rankin scores (mRS) at 90 days, 24-hour mean infarct volumes, time to reperfusion, and symptomatic intracerebral hemorrhage (sICH) rates were evaluated.

Results: When compared to those with ≥70% stenosis, patients with <70% stenosis had a lower mean mRS at 90 days (2.9 vs 3.3, p=0.10), greater percentage of mRS 0-2 (43.5 vs 34.3%, p=0.15), smaller mean infarction volume (70.1 vs 87.6mL, p=0.18), shorter mean time to reperfusion (78.7 vs 105.7 minutes, p=0.002), and a higher rate of sICH (7.3 vs 2.7%, p=0.15).

Conclusion: In patients receiving combined IV/IA treatment for AIS, ipsilateral ICA stenosis of ≥70% is associated with a statistically significant longer time to reperfusion, and trends favoring larger infarct volumes and worse clinical outcomes despite a lower rate of sICH.

Managing the consequences of aggressive conservative treatment for refractory retinoblastoma with vitreous seeding

A 4 year-old girl with bilateral, non-familial retinoblastoma (RB) was referred to our care after primary enucleation OS and active tumor OD refractory to multiple therapies (intravenous chemotherapy, laser/cryotherapy, and I-125 plaque radiotherapy). Vitreous seeding OD, initially controlled by several sessions of Ophthalmic Artery Infusion Chemotherapy (OAIC) and periocular chemotherapy, recurred shortly thereafter. The patient underwent intravitreal (IVit) Melphalan injections achieving tumor control despite the concurrent development of keratopathy, pupillary synechiae, cataract, and necrosis of the inferior fornix and the adjacent orbital fat, all secondary to the treatments administered. Repeated amniotic membrane implants and tarsorrhaphy were performed to alleviate the symptoms. Despite being tumor free for 6 months, a poor fundus view and treatment-related complications prompted us to consider enucleation, but parents declined. Following recent negative magnetic resonance imaging (MRI), her cataract was removed. She was then found to have tumor recurrence. Her eye was enucleated 12 months ago and she recovered well from the surgery. As ocular oncology embarks in eye-preserving treatments for retinoblastoma, it is important to address the cumulative effects and associated impact of such treatments and the possibility of failure.

Geographic access to acute stroke care in the United States

BACKGROUND AND PURPOSE

Only 3% to 5% of patients with acute ischemic stroke receive intravenous recombinant tissue-type plasminogen activator (r-tPA) and <1% receive endovascular therapy. We describe access of the US population to all facilities that actually provide intravenous r-tPA or endovascular therapy for acute ischemic stroke.

METHODS

We used US demographic data and intravenous r-tPA and endovascular therapy rates in the 2011 US Medicare Provider and Analysis Review data set. International Classification of Diseases-Ninth Revision codes 433.xx, 434.xx and 436 identified acute ischemic stroke cases. International Classification of Diseases-Ninth Revision code 99.10 defined intravenous r-tPA treatment and International Classification of Diseases-Ninth Revision code 39.74 defined endovascular therapy. We estimated ambulance response times using arc-Geographic Information System's network analyst and helicopter transport times using validated models. Population access to care was determined by summing the population contained within travel sheds that could reach capable hospitals within 60 and 120 minutes.

RESULTS

Of 370,351 acute ischemic stroke primary diagnosis discharges, 14,926 (4%) received intravenous r-tPA and 1889 (0.5%) had endovascular therapy. By ground, 81% of the US population had access to intravenous-capable hospitals within 60 minutes and 56% had access to endovascular-capable hospitals. By air, 97% had access to intravenous-capable hospitals within 60 minutes and 85% had access to endovascular hospitals. Within 120 minutes, 99% of the population had access to both intravenous and endovascular hospitals.

CONCLUSIONS

More than half of the US population has geographic access to hospitals that actually deliver acute stroke care but treatment rates remain low. These data provide a national perspective on acute stroke care and should inform the planning and optimization of stroke systems in the United States.

Changes in computed tomography perfusion parameters after superficial temporal artery to middle cerebral artery bypass: an analysis of 29 cases

Introduction Analysis of computed tomography perfusion (CTP) studies before and after superficial temporal artery to middle cerebral artery (STA-MCA) bypass is warranted to better understand cerebral steno-occlusive pathology. Methods Retrospective review was performed of STA-MCA bypass patients with steno-occlusive disease with CTP before and after surgery. CTP parameters were evaluated for change after STA-MCA bypass. Results A total of 29 hemispheres were bypassed in 23 patients. After STA-MCA bypass, mean transit time (MTT) and time to peak (TTP) improved. When analyzed as a ratio to the contralateral hemisphere, MTT, TTP, and cerebral blood flow (CBF) improved. There was no effect of gender, double vessel versus single vessel bypass, or time until postoperative CTP study to changes in CTP parameters after bypass. Conclusions Blood flow augmentation after STA-MCA bypass may best be assessed by CTP using baseline MTT or TTP and ratios of MTT, TTP, or CBF to the contralateral hemisphere. The failure of cerebrovascular reserve to improve after cerebral bypass may indicate irreversible loss of autoregulation with chronic cerebral vasodilation or the inability of CTP to detect these improvements.