Risk factors for the development of secondary intracranial hypertension in acute cerebral venous thrombosis.

PURPOSE: Intracranial hypertension (IH) can complicate cerebral venous thrombosis (CVT), potentially causing permanent visual loss. Current knowledge on risk factors for the development of IH following CVT is scarce. We applied a compound classifier (CSF opening pressure > 25 cmH2O, papilledema, or optic disc protrusion on MRI) as a surrogate for IH and studied the predictive value of thrombus location, the number of thrombosed segments, and thrombus volume. METHODS: We prospectively included 26 patients with acute CVT and complete MRI data. IH was defined by CSF opening pressure > 25 cmH2O, papilledema, or optic disc protrusion on MRI. Using high-resolution contrast-enhanced venography, we determined the thrombus location, number of thrombosed segments, and thrombus volume. We analyzed their association with IH by logistic regression, their predictive power by the area under the receiver operating characteristic curve, and their association with CSF opening pressure by linear regression. RESULTS: IH occurred in 46% of CVT patients and was associated with higher thrombus volume (AUC 0.759, p = 0.025) and superior sagittal sinus thrombosis both alone (OR 2.086, p = 0.049) and combined with transverse sinus thrombosis (OR 2.014, p = 0.028). Effects in patients presenting CSF opening pressure > 25 cm H2O and the compound classifier were consistent. Thrombus volume > 4 ml was the single most important predictor of higher CSF opening pressure (ß = 0.566, p = 0.035), increasing IH risk. CONCLUSION: Larger thrombus volume, dominant transverse sinus occlusion, and extensive superior sagittal combined with transverse sinus thrombosis were associated with IH. Thrombus volumetry might identify patients at risk for IH and direct further clinical evaluation.

[Transcatheter aortic valve implantation and internal carotid artery stenting in a 74-year-old female patient]. / Transkutaner Aortenklappenersatz kombiniert mit Stenting der A. carotis interna bei einer 74-jährigen Patientin.

This article presents the case of a combined intervention for transcatheter aortic valve implantation (TAVI) and stenting of the internal carotid artery. Due to severe aortic stenosis and a subacute infarction in the middle cerebral artery territory, with neurological instability while hypotensive and cardiac failure while hypertensive, it was decided to carry out the intervention as a single combined procedure. An open surgical intervention was decided against because of the high peri-interventional mortality risk. The intervention was complication-free but a slight subarachnoid hemorrhage occurred in the postinterventional period. It was unclear if the bleeding was the result of cerebral hyperperfusion poststenting, if bleeding in an ischemic region was favored by post-TAVI hyperemia and whether the outcome would have been better with two separate interventions.

Distribution of internal carotid artery plaque locations among patients with central retinal artery occlusion in the Eagle study population.

PURPOSE: Arterial emboli in the internal carotid artery (ICA) mainly cause cerebral ischemia; only 10 % of emboli reach the retinal arteries. Computational blood flow studies suggest that plaques situated in the ICA siphon may be a source of embolism to the ophthalmic artery (OA). To validate these calculated probabilities in patients with central retinal artery occlusion (CRAO), we reanalyzed digital subtraction angiography (DSA) images from the Multicenter Study of the European Assessment Group for Lysis in the Eye (EAGLE) study, a multicenter randomized study in patients with nonarteritic CRAO. METHODS: A reevaluation of 34 DSA studies was done from the interventional arm of the EAGLE study with regards to distribution of arterial plaques at specific ICA siphon locations and ICA stenosis. A comparison was made of plaque distribution to calculated probabilities for emboli reaching the OA from a computational fluid dynamics (CFD) model of a patient-specific ICA siphon. RESULTS: Most of the ICA plaques near the OA's origin were located in the cavernous ICA portion (31.3%). Of these, 12.5 % had plaques in the curvature opposite the OA origin, a location carrying the highest risk for embolization into the OA (according to the CFD model 12.6-13.2 % probability of embolisation into the OA). Also, 15.6 % had plaques in the paraclinoid ICA portion distal to the OA origin. CONCLUSIONS: There were 40.6% of the patients that had plaques in the cavernous and clinoid ICA portions presenting possible sources for embolic material generating RAO.

[Mechanical thrombectomy for acute ischemic stroke : current evidence and open questions]. / Mechanische Thrombektomie beim ischämischen Schlaganfall : Studienlage und offene Fragen.

OBJECTIVE: To determine the importance of mechanical thrombectomy (MT) in the treatment of ischemic stroke. MATERIAL AND METHODS: Analysis and comparison of randomized controlled trials (RCT) of MT versus i.v. thrombolysis (IVT) considering pathophysiological and logistic aspects. RESULTS: The use of MT is more effective than IVT for internal carotid artery terminus (ICAT), M1 segment and tandem occlusions, i.e. proximal internal carotid artery (ICA) occlusion or stenosis, even in patients older than 75-80 years of age. Due to the small sample sizes this question cannot be answered for patients with M2 occlusions. It is still uncertain whether MT is needed in patients with a low National Institutes of Health stroke scale (NIHSS) score, whether IVT is needed before MT and what type of imaging should be performed. Approximately one third of eligible patients currently undergo MT in Germany. Results from RCTs with stent retrievers for patients with vertebrobasilar artery occlusions are lacking. CONCLUSION: After becoming established as a first-line therapy for patients with ICAT, M1 segment and tandem occlusions, the effectiveness of MT with stent retrievers has to proven in patients with more distal occlusions, low NIHSS scores and even vertebrobasilar artery occlusions.

[Peripheral facial palsy after embolization of a dural arteriovenous fistula with Onyx®]. / Periphere Fazialisparese nach Onyx®-Embolisation einer duralen arteriovenösen Fistel.

Dural arteriovenous fistulas (DAVF) are intracranial vascular malformations which can cause severe complications, such as intracranial bleeding and neurological deficits. We report the case of a patient presenting with pulsatile tinnitus caused by a DAVF. The DAVF was endovascularly treated including transarterial embolization with the liquid embolic agent Onyx®. The fistula and tinnitus were cured successfully, however, the rare complication of facial nerve palsy due to reflux of Onyx® into the vasa nervorum occurred. This could be confirmed directly during surgery and by histological analysis.

High-Resolution Gadolinium-Enhanced MR Cisternography Using Compressed-Sensing T1 SPACE Technique for Detection of Intracranial CSF Leaks.

In patients with CSF rhinorrhea, accurate identification of the CSF leakage site is crucial for surgical planning. We describe the application of a novel gadolinium-enhanced high-resolution 3D compressed-sensing T1 SPACE technique for MR cisternography and compare findings with CT cisternography and intraoperative results. In our pilot experience with 7 patients, precise detection of CSF leaks was feasible using compressed-sensing T1 SPACE, which appeared to be superior to CT cisternography.

Contrast Enhancement of Intracranial Aneurysms on 3T 3D Black-Blood MRI and Its Relationship to Aneurysm Recurrence following Endovascular Treatment.

BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms aims at preventing aneurysm rupture. Contrast-enhanced black-blood MR imaging facilitates imaging of the vessel walls and the aneurysmal sac contents and is therefore suitable for studying the healing process. This study aims to describe imaging findings of aneurysmal contrast enhancement following endovascular treatment and its correlation to recurrence and elapsed time since coiling. MATERIALS AND METHODS: Patients undergoing MR imaging follow-up after endovascular treatment of an intracranial aneurysm were included. Contrast-enhanced black-blood T1WI was acquired. Aneurysm wall and intra-aneurysmal enhancement were independently assessed by 2 neuroradiologists and were related to the time elapsed since coiling and the presence of recurrence. RESULTS: Thirty aneurysms in 30 patients were included. The median time elapsed since treatment was 417 days (interquartile range, 189-1273 days). Aneurysmal contrast enhancement was seen in 24/30 (80%) aneurysms. Enhancement inside the sac in 55% (n = 17), the wall in 23% (n = 7), at the dome (n = 1), or at the base (n = 6) was observed. No statistically significant correlation between aneurysmal contrast enhancement and the elapsed time (P = .83) and presence of a recurrence (P = .184) was detected. In 28/30 patients, the images were of adequate diagnostic quality. Stent implants caused negligible image artifacts. CONCLUSIONS: Intra-aneurysmal contrast enhancement following endovascular treatment of intracranial aneurysms is a common finding and likely reflects the healing process. A long-term study to examine changes occurring with time and their association with packing density, type of coils (bare platinum versus bioactive coils), and aneurysm recurrence is underway (German Clinical Trials Register, DRKS-ID: DRKS00014644).

MR angiography of dural arteriovenous fistulas: diagnosis and follow-up after treatment using a time-resolved 3D contrast-enhanced technique.

BACKGROUND AND PURPOSE: Digital subtraction angiography (DSA) is the method of reference for imaging of dural arteriovenous fistula (DAVF). The goal of this study was to analyze the value of different MR images including 3D contrast-enhanced MR angiography (MRA) with a high temporal resolution in diagnostic and follow-up imaging of DAVFs. MATERIALS AND METHODS: A total of 18 MR/MRA examinations from 14 patients with untreated (n=9) and/or treated (n=9) DAVFs were evaluated. Two observers assessed all MR and MRA investigations for signs indicating the presence of a DAVF, for fistula characteristics such as fistula grading, location of fistulous point, and fistula obliteration after treatment. All results were compared with DSA findings. RESULTS: On time-resolved 3D contrast-enhanced (TR 3D) MRA, the side and presence of all patent fistulas (n=13) were correctly indicated, and no false-positive findings were observed in occluded DAVFs (n=5). Grading of fistulas with this imaging technique was correct in 77% and 85% of patent fistulas for both readers, respectively. On T2-weighted images, signs indicative of a DAVF were encountered only in fistulas with cortical venous reflux (56%), whereas on 3D time-of-flight (TOF) MRA, most fistulas (88%) were correctly detected. In complete fistula occlusion, false-positive findings were encountered on both T2-weighted images and on TOF MRA images. CONCLUSION: In this study, TR 3D MRA proved reliable in detecting DAVFs and suitable for follow-up imaging. The technique allowed--within limitations--to grade DAVFs. Although 3D TOF MRA can depict signs of DAVFs, its value for follow-up imaging is limited.

In vivo assessment and visualization of intracranial arterial hemodynamics with flow-sensitized 4D MR imaging at 3T.

SUMMARY: We evaluated electrocardiogram-synchronized flow-sensitized 4-dimensional MR imaging at 3T in combination with advanced 3D visualization strategies to ascertain its feasibility for the assessment of local intracranial blood-flow patterns in vivo. In large arteries of healthy volunteers, the temporal and spatial evolution of blood flow was successfully visualized and revealed--for example, a helical flow pattern in the carotid siphon. In a patient with steno-occlusive neurovascular disease, stagnant and retrograde flow patterns were readily visible.

Surpass Flow Diverter for Treatment of Posterior Circulation Aneurysms.

BACKGROUND AND PURPOSE: Flow diverters for the treatment of posterior circulation aneurysms remain controversial. We aimed to identify factors contributing to outcome measures in patients treated with the Surpass flow diverter for aneurysms in this location. MATERIALS AND METHODS: We conducted an observational study of 53 patients who underwent flow-diverter treatment for posterior circulation aneurysms at 15 centers. Key outcome measures were mortality, complete aneurysm occlusion, and modified Rankin Scale score at follow-up. RESULTS: At follow-up (median, 11.3 months; interquartile range, 5.9-12.7 months), 9 patients had died, resulting in an all-cause mortality rate of 17.3% (95% CI, 7%-27.6%); 7 deaths (14%) were directly related to the procedure and none occurred in patients with a baseline mRS score of zero. After adjusting for covariates, a baseline mRS of 3-5 was more significantly (P = .003) associated with a higher hazard ratio for death than a baseline mRS of 0-2 (hazard ratio, 17.11; 95% CI, 2.69-109.02). After adjusting for follow-up duration, a 1-point increase in the baseline mRS was significantly (P < .001) associated with higher values of mRS at follow-up (odds ratio, 2.93; 95% CI, 1.79-4.79). Follow-up angiography in 44 patients (median, 11.3 months; interquartile range, 5.9-12.7 months) showed complete aneurysm occlusion in 29 (66%; 95% CI, 50.1%-79.5%). CONCLUSIONS: Clinical results of flow-diverter treatment of posterior circulation aneurysms depend very much on patient selection. In this study, poorer outcomes were related to the treatment of aneurysms in patients with higher baseline mRS scores. Angiographic results showed a high occlusion rate for this subset of complex aneurysms.

Facing the Time Window in Acute Ischemic Stroke: The Infarct Core.

BACKGROUND: Increasing numbers needed to treat within the first hours after ischemic stroke onset indicate a strong time dependency of the viability of brain tissue. However, this time dependency is not reflected in recent randomized controlled trials of endovascular stroke treatment. This study evaluates whether and to which extent a time dependency exists in patients with embolic carotid T or M1 occlusions within the first 6 h of stroke onset. METHODS: Patient data were retrieved from the Freiburg stroke data bank. Time from onset to acquisition of the diffusion weighted images (DWIs) varied between 49 and 357 min. Ischemic lesions were semiautomatically segmented on apparent diffusion coefficient maps with a threshold of 600 × 10 (- 6) mm(2)/s. Occlusion location and thrombus length were determined with magnetic resonance angiography, T2*, and more recently susceptibility weighted image (SWI) sequences. A hyperintense vessel sign in FLAIR images as a possible surrogate for collaterals was also identified. RESULTS: A total of 155 patients with occlusions of the carotid T (n = 26), proximal M1 segment (n = 44), and distal M1 segment (n = 85) of the middle cerebral artery between 2011 and 2015 were included. Infarct volumes varied from 0.3 to 180.2 mL. Infarct size did not correlate with stroke onset to DWI times. Infarct volumes also did not associate with different locations of vessel occlusion, thrombus length, presence of the hyperintense vessel sign and initial infarct growth. CONCLUSION: We found no significant time dependency of the viability of brain tissue with embolic carotid T or M1 occlusions between 1 and 6 h after stroke onset. The early infarction volume is thus probably determined in the hyperacute phase by the quality of leptomeningeal collaterals and comparatively stable in this time period.

Endovascular Cooling Catheter for Selective Brain Hypothermia: An Animal Feasibility Study of Cooling Performance.

BACKGROUND AND PURPOSE: Therapeutic hypothermia represents a promising neuroprotective treatment in acute ischemic stroke. Selective cerebral hypothermia applied early, prior to and during endovascular mechanical recanalization therapy, may be beneficial in the critical phase of reperfusion. We aimed to assess the feasibility of a new intracarotid cooling catheter in an animal model. MATERIALS AND METHODS: Nine adult sheep were included. Temperature probes were introduced into the frontal and temporal brain cortices bilaterally. The cooling catheter system was introduced into a common carotid artery. Selective blood cooling was applied for 180 minutes. Systemic and local brain temperatures were measured during cooling and rewarming. Common carotid artery diameters and flow were measured angiographically and by Doppler sonography. RESULTS: The common carotid artery diameter was between 6.7 and 7.3 mm. Common carotid artery blood flow velocities increased moderately during cooling and after catheter removal. Maximum cerebral cooling in the ipsilateral temporal cortex was -4.7°C (95% CI, -5.1 to -4.0°C). Ipsilateral brain temperatures dropped significantly faster and became lower compared with the contralateral cortex with maximum temperature difference of -1.3°C (95% CI, -1.5 to -1.0°C; P < .0001) and compared with systemic temperature (-1.4°C; 95% CI, -1.7 to -1.0°C; P < .0001). CONCLUSIONS: Sheep proved a feasible animal model for the intracarotid cooling catheter. Fast induction of selective mild hypothermia was achieved within the cooled cerebral hemisphere, with stable temperature gradients in the contralateral brain and systemic blood. Further studies are required to demonstrate any therapeutic benefit of selective cerebral cooling in a stroke model.

Combined Selective Cerebral Hypothermia and Mechanical Artery Recanalization in Acute Ischemic Stroke: In Vitro Study of Cooling Performance.

BACKGROUND AND PURPOSE: Therapeutic hypothermia represents a promising neuroprotective treatment for patients with ischemic stroke. Selective, intracarotid blood cooling may initiate rapid and early brain hypothermia, reduce systemic effects, and allow combined endovascular mechanical thrombectomy. For this approach, a balloon cooling catheter system was designed and studied in vitro to optimize its cooling performance. MATERIALS AND METHODS: Computational fluid dynamics of blood cooling was performed within the common carotid artery lumen by using 3 different catheter designs (1-, 2-, and 4-balloon array). On the basis of these results, a first catheter prototype was manufactured, and its heat-exchange performance was tested in an artificial in vitro circulation simulating the common carotid artery lumen at different flow rates (inflow temperature of 37°C). RESULTS: In the computational fluid dynamics model, the catheter with the 4-balloon array achieved the highest cooling rate of -1.6°C, which may be attributed to disruption of the thermal boundary layers. In the in vitro study, cooling of the blood substitute at flow rates of 400 mL/min (normal common carotid artery flow) and 250 mL/min (reduced common carotid artery flow due to distal MCA occlusion) achieved a temperature drop inside the blood substitute along the cooling balloons of -1.6°C and -2.2°C, respectively. CONCLUSIONS: The feasibility of intracarotid blood cooling using a new catheter system was demonstrated in vitro. A serial 4-balloon array led to an optimized cooling capacity approaching optimum target temperatures of mild therapeutic hypothermia. To determine the therapeutic efficacy of combined selective therapeutic hypothermia and mechanical thrombectomy, further in vivo studies by using a model of temporary ischemia with large-vessel occlusion and recanalization are required.

Double solitaire mechanical thrombectomy in acute stroke: effective rescue strategy for refractory artery occlusions?

BACKGROUND AND PURPOSE: Mechanical thrombectomy by using a single stent retriever system has demonstrated high efficacy for recanalization of large-artery occlusions in acute stroke. We aimed to evaluate the feasibility, safety, and efficacy of a novel double Solitaire stent retriever technique as an escalating treatment for occlusions that are refractory to first-line single stent retriever mechanical thrombectomy. MATERIALS AND METHODS: All patients treated with the double stent retriever technique by using the Solitaire system were retrospectively selected from 2 large neurointerventional centers. Time to recanalization, angiographic (TICI) and clinical outcomes (mRS), and complications were assessed. RESULTS: Ten patients (median NIHSS score, 16; mean age, 70 years) with MCA M1 segment (n = 5) and terminal ICA (n = 5 including 2 ICA tandem) occlusions were included. Prior single stent retriever mechanical thrombectomy had been performed in 9 patients (median number of passes, 3). Median time to recanalization was 60 minutes (interquartile range, 45-87 minutes). Procedure-related complications occurred in 1 patient; overall mortality was 20%. Recanalization of the target vessel (TICI 2b/3) was achieved in 80%. Good clinical outcome (mRS 0-2) was 50%. CONCLUSIONS: In this preliminary feasibility study, the double Solitaire stent retriever technique proved to be an effective method for recanalization of anterior circulation large-artery occlusions refractory to standard stent retriever mechanical thrombectomy.

MR angiography at 3 Tesla to assess proximal internal carotid artery stenoses: contrast-enhanced or 3D time-of-flight MR angiography?

PURPOSE: The aim of this study was to compare the diagnostic accuracy of 3D time-of-flight (TOF-MRA) and contrast-enhanced (CE-MRA) magnetic resonance angiography at 3 T for detection and quantification of proximal high-grade stenosis using multidetector computed tomography angiography (MDCTA) as reference standard. METHODS: The institutional ethics committee approved this prospective study. A total of 41 patients suspected of having internal carotid artery (ICA) stenosis underwent both MDCTA and MRA. CE-MRA and TOF-MRA were performed using a 3.0-T imager with a dedicated eight-element cervical coil. ICA stenoses were measured according to the North American Symptomatic Carotid Endarterectomy Trial criteria and categorized as 0-25 % (minimal), 25-50 % (mild), 50-69 % (moderate), 70-99 % (high grade), and 100 % (occlusion). Sensitivity and specificity for the detection of high-grade ICA stenoses (70-99 %) and ICA occlusions were determined. In addition, intermodality agreement was assessed with κ-statistics for detection of high-grade ICA stenoses (70-99 %) and ICA occlusions. RESULTS: A total of 80 carotid arteries of 41 patients were reviewed. Two previously stented ICAs were excluded from analysis. On MDCTA, 7 ICAs were occluded, 12 ICAs presented with and 63 without a high-grade ICA stenosis (70-99 %). For detecting 70-99 % stenosis, both 3D TOF-MRA and CE-MRA were 91.7 % sensitive and 98.5 % specific, respectively. Both MRA techniques were highly sensitive (100 %), and specific (CE-MRA, 100 %; TOF-MRA, 98.7 %) for the detection of ICA occlusion. However, TOF-MRA misclassified one high-grade stenosis as occlusion. Intermodality agreement for detection of 70-99 % ICA stenoses was excellent between TOF-MRA and CE-MRA [κ = 0.902, 95 % confidence interval (CI) = 0.769-1.000], TOF-MRA and MDCTA (κ = 0.902, 95 % CI = 0.769-1.000), and CE-MRA and MDCTA (κ = 0.902, 95 % CI = 0.769-1.000). CONCLUSION: Both 3D TOF-MRA and CE-MRA at 3 T are reliable tools for detecting high-grade proximal ICA stenoses (70-99 %). 3D TOF-MRA might misclassify pseudo-occlusions as complete occlusions. If there are no contraindications for CE-MRA, CE-MRA is recommended as primary MR imaging modality.

Safety of the pipeline embolization device in treatment of posterior circulation aneurysms.

BACKGROUND AND PURPOSE: The published results of treating internal carotid artery aneurysms with the PED do not necessarily apply to its use in the posterior circulation because disabling brain stem infarcts can be caused by occlusion of a single perforator. In this multicenter study, we assessed the safety of PED placement in the posterior circulation. MATERIALS AND METHODS: A prospective case registry was maintained of all posterior circulation aneurysms treated with PEDs at 3 Australian neurointerventional centers during a 27-month period. The objective was to assess the complications and aneurysm occlusion rates associated with posterior circulation PEDs. RESULTS: Thirty-two posterior circulation aneurysms were treated in 32 patients. No deaths or poor neurologic outcomes occurred. Perforator territory infarctions occurred in 3 (14%) of the 21 patients with basilar artery aneurysms, and in all 3, a single PED was used. Two asymptomatic intracranial hematomas were recorded. No aneurysm rupture or PED thrombosis was encountered. The overall rate of permanent neurologic complications was 9.4% (3/32); all 3 patients had very mild residual symptoms and a good clinical outcome. Aneurysm occlusion was demonstrated in 85% of patients with >6 months of follow-up and 96% of patients with >1 year of follow-up. CONCLUSIONS: The PED is effective in the treatment of posterior circulation aneurysms that are otherwise difficult or impossible to treat with standard endovascular or surgical techniques, and its safety is similar to that of stent-assisted coiling techniques. A higher clinical perforator infarction rate may be associated with basilar artery PEDs relative to the internal carotid artery.