Faculty Bibliography

Despite the severity of coronavirus disease 2019 (COVID-19) being more frequently related to acute respiratory distress syndrome and acute cardiac and renal injuries, thromboembolic events have been increasingly reported. We report a unique series of young patients with COVID-19 presenting with cerebral venous system thrombosis. Three patients younger than 41 years of age with confirmed Severe Acute Respiratory Syndrome coronavirus 2 (SARS-Cov-2) infection had neurologic findings related to cerebral venous thrombosis. They were admitted during the short period of 10 days between March and April 2020 and were managed in an academic institution in a large city. One patient had thrombosis in both the superficial and deep systems; another had involvement of the straight sinus, vein of Galen, and internal cerebral veins; and a third patient had thrombosis of the deep medullary veins. Two patients presented with hemorrhagic venous infarcts. The median time from COVID-19 symptoms to a thrombotic event was 7 days (range, 2-7 days). One patient was diagnosed with new-onset diabetic ketoacidosis, and another one used oral contraceptive pills. Two patients were managed with both hydroxychloroquine and azithromycin; one was treated with lopinavir-ritonavir. All patients had a fatal outcome. Severe and potentially fatal deep cerebral thrombosis may complicate the initial clinical presentation of COVID-19. We urge awareness of this atypical manifestation.

BACKGROUND AND PURPOSE/OBJECTIVE:Tentorial sinus venous channels within the tentorium cerebelli connecting various cerebellar and supratentorial veins, as well as the basal vein, to adjacent venous sinuses are a well-recognized entity. Also well-known are "dural lakes" at the vertex. However, the presence of similar channels in the supratentorial dura, serving as recipients of the Labbe, superficial temporal, and lateral and medial parieto-occipital veins, among others, appears to be underappreciated. Also under-recognized is the possible role of these channels in the angioarchitecture of certain high-grade dural fistulas. MATERIALS AND METHODS/METHODS:A retrospective review of 100 consecutive angiographic studies was performed following identification of index cases to gather data on the angiographic and cross-sectional appearance, location, length, and other features. A review of 100 consecutive dural fistulas was also performed to identify those not directly involving a venous sinus. RESULTS:Supratentorial dural venous channels were found in 26% of angiograms. They have the same appearance as those in the tentorium cerebelli, a flattened, ovalized morphology owing to their course between 2 layers of the dura, in contradistinction to a rounded cross-section of cortical and bridging veins. They are best appreciated on angiography and volumetric postcontrast T1-weighted images. Ten dural fistulas not directly involving a venous sinus were identified, 6 tentorium cerebelli and 4 supratentorial. CONCLUSIONS:Supratentorial dural venous channels are an under-recognized entity. They may play a role in the angioarchitecture of dural arteriovenous fistulas that appear to drain directly into a cortical vein. We propose "dural venous channel" as a unifying name for these structures.

OBJECTIVE:Previous studies have demonstrated the importance of intracranial elastance; however, methodological difficulties have limited widespread clinical use. Measuring elastance may offer potential benefit in helping to identify patients at risk for untoward intracranial pressure (ICP) elevation from small rises in intracranial volume. The authors sought to develop an easily used method that accounts for the changing ICP that occurs over a cardiac cycle and to assess this method in a large-animal model over a broad range of ICPs. METHODS:The authors used their previously described cardiac-gated intracranial balloon pump and swine model of cerebral edema. In the present experiment they measured elastance at 4 points along the cardiac cycle-early systole, peak systole, mid-diastole, and end diastole-by using rapid balloon inflation to 1 ml over an ICP range of 10-30 mm Hg. RESULTS:The authors studied 7 swine with increasing cerebral edema. Intracranial elastance rose progressively with increasing ICP. Peak-systolic and end-diastolic elastance demonstrated the most consistent rise in elastance as ICP increased. Cardiac-gated elastance measurements had markedly lower variance within swine compared with non-cardiac-gated measures. The slope of the ICP-elastance curve differed between swine. At ICP between 20 and 25 mm Hg, elastance varied between 8.7 and 15.8 mm Hg/ml, indicating that ICP alone cannot accurately predict intracranial elastance. CONCLUSIONS:Measuring intracranial elastance in a cardiac-gated manner is feasible and may offer an improved precision of measure. The authors' preliminary data suggest that because elastance values may vary at similar ICP levels, ICP alone may not necessarily best reflect the state of intracranial volume reserve capacity. Paired ICP-elastance measurements may offer benefit as an adjunct "early warning monitor" alerting to the risk of untoward ICP elevation in brain-injured patients that is induced by small increases in intracranial volume.

BACKGROUND:Verification of complete occlusion or resection of neurovascular lesions is often done with intraoperative angiography. Surgery for spinal vascular lesions such as arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) is typically performed in the prone position making intraoperative angiography difficult. There is no standardized protocol for intraoperative angiography in spinal surgeries performed in the prone position. OBJECTIVE:We describe our experience with using radial artery access for intraoperative angiography in thoracic spinal neurovascular procedures performed with patients in the prone position. METHODS:We reviewed all patients who underwent surgical resection of spinal vascular lesions in the prone position with radial artery vascular access for intraoperative angiography. Patients were treated in a hybrid endovascular operating room. RESULTS:4 patients were treated in the pone position utilizing transradial artery access intraoperative angiography for confirmation of complete resection of the vascular lesions. 2 patients were operated for dural AVFs, one patient had a pial AVF, and one patient had an AVM of the filum terminale. None of the patients faced any procedural complications. CONCLUSION/CONCLUSIONS:Radial artery access for intraoperative angiography in spinal neurovascular procedures in which selective catheterization of a thoracic branch is necessary, is feasible, safe, and practical.

INTRODUCTION/BACKGROUND:The glial-lymphatic pathway is a fluid-clearance pathway consisting of a para-arterial route for the flow of cerebrospinal fluid along perivascular spaces and subsequently toward the brain interstitium. In this case series we aim to investigate an empirical demonstration of glymphatic clearance of extravasated iodine following perforation incurred during endovascular therapy on serial CT. METHODS AND RESULTS/RESULTS:Six consecutive cases of endovascular perforation during thrombectomy performed between 2005 and 2018 were retrospectively collected by searching our internal database of total 446 thrombectomies. Two cases were excluded because care was withdrawn shortly following the procedure and no follow-up imaging was available. One case was excluded because a ventricular drain was placed. Three cases were hence included in this analysis. All three cases demonstrated progressive absorption of contrast by the brain parenchyma with eventual contrast disappearance. CONCLUSION/CONCLUSIONS:We described a likely in vivo CT correlate of the glymphatic system in a cohort of patients who sustained intraprocedural extravasation during thrombectomy for acute ischemic stroke.

Flow diverters (FDs) have changed the management of brain aneurysms; not only for complex aneurysms (giant, fusiform and blister) refractory to conventional therapies, but also for unruptured lesions previously managed by traditional surgical or coil-based endovascular methods. Since 2011 when the PipelineTM Embolization Device (Medtronic) was cleared by the Food and Drug Administration for adults with large or giant wide-neck intracranial aneurysms of the internal carotid artery proximal to the posterior communicating segment, the role of flow diversion for aneurysm treatment has expanded-supported by favorably low complication and high cure rates compared with alternative treatments. Here we review the key clinical trials and the long term outcomes that have demonstrated safety and efficacy of minimized porosity endoluminal devices in the treatment of cerebral aneurysms.

OBJECTIVE:Cavernous carotid fistulas (CCF) are anatomically complex vascular lesions. Treatment via the venous approach has been previously described and is highly dependent on the patency of the drainage pathways. The use of a unilateral approach to contralateral or bilateral shunts is technically challenging and not commonly described. We present our experience with the unilateral across-the-midline approach to both cavernous sinuses to treat shunts according to anatomical compartments to achieve anatomical cure. METHODS:Patients included in this study presented with either bilateral or unilateral shunts with unilateral venous drainage. We used a trans-arterial guiding catheter for road mapping and control angiography. A venous tri-axial system was used to achieve support for distal navigation across the midline via the coronary sinus to the contralateral cavernous sinus. Coils were favored for embolization with occasional complementary liquid embolic material. RESULTS:Five patients underwent complete occlusion in a single session. One patient required additional complimentary trans-arterial embolization. Despite a successful unilateral approach to bilateral cavernous sinuses, one patient needed an additional ipsilateral trans-ophthalmic vein approach to obliterate the anterior compartment of the cavernous sinus. No complications were encountered. Complete angiographic cure was observed in all patients by the end of the final procedures, with persistent occlusion in their follow up imaging. CONCLUSION/CONCLUSIONS:Careful inspection of the venous anatomy and fistulization sites is critical when treating unilateral or bilateral Carotid Cavernous shunts. The contralateral venous route can serve as a safe approach when visualized. Crossing the midline via the anterior or posterior coronary sinuses is feasible and efficacious.

PURPOSE/OBJECTIVE:To develop a preclinical model of stroke with a large vessel occlusion treated with mechanical thrombectomy. MATERIALS AND METHODS/METHODS:An ischemic stroke model was created in dogs by the introduction of an autologous clot into the middle cerebral artery (MCA). A microcatheter was navigated to the clot and a stent retriever thrombectomy was performed with the goal to achieve Thrombolysis in Cerebral Ischemia (TICI) 2b/3 reperfusion. Perfusion and diffusion MRI was acquired after clot placement and following thrombectomy to monitor the progression of restricted diffusion as well as changes in ischemia as a result of mechanical thrombectomy. Post-mortem histology was done to confirm MCA territory infarct volume. RESULTS:Initial MCA occlusion with TICI 0 flow was documented in all six hound-cross dogs entered into the study. TICI 2b/3 revascularization was achieved with one thrombectomy pass in four of six animals (67%). Intra-procedural events including clot autolysis leading to spontaneous revascularization (n=1) and unresolved vasospasm (n=1) accounted for thrombectomy failure. In one case, iatrogenic trauma during microcatheter navigation resulted in a direct arteriovenous fistula at the level of the cavernous carotid. Analysis of MRI indicated that a volume of tissue from the initial perfusion deficit was spared with reperfusion following thrombectomy, and there was also a volume of tissue that infarcted between MRI and ultimate recanalization. CONCLUSION/CONCLUSIONS:We describe a large animal stroke model in which mechanical thrombectomy can be performed. This model may facilitate, in a preclinical setting, optimization of complex multimodal stroke treatment paradigms for clinical translation.

BACKGROUND:The treatment of selected wide-neck and fusiform posterior circulation aneurysms is challenging for clipping as well as for endovascular route. OBJECTIVE:To describe an endovascular approach for vertebral artery aneurysm treatment using transradial access (TRA) instead of the conventional transfemoral access. METHODS:We collected cases from two institutions in which TRA was used for posterior circulation Pipeline Embolization Device (Medtronic, Dublin, Ireland) deployment. RESULTS:A total of four patients were treated. TRA was useful in the setting of extreme vessel tortuosity. We utilized 5F Terumo Glidesheath (Terumo Medical, Somerset, New Jersey), intermediate catheter, and a 027 microcatheter for Pipeline deployment. TRA was not associated with any access or deployment difficulties. CONCLUSIONS:Early experience suggests that TRA for Pipeline Embolization Device placement for posterior circulation aneurysm is a safe and efficient alternative to standard transfemoral access. While this approach was initially applied to patients with vascular anatomy that may not allow for safe femoral access or navigation, experience so far argues for considering a radial approach towards some posterior circulation aneurysm treatment.