25 research outputs found
Utility of Hounsfield unit in the diagnosis of tandem occlusion in acute ischemic stroke
Background Tandem occlusions can complicate medical and endovascular stroke treatment. To identify these occlusions,
computed tomography angiography (CTA) represents the best imaging modality. However, CTA is still not initially performed
in some patients not admitted directly to stroke centers. Early identification of an additional occlusion of the proximal extracranial
internal carotid artery may improve the best suitable treatment strategy. The purpose of this study was to find a valuable threshold
of thrombus attenuation in a non-contrast head CT (NCCT) scan to facilitate a safe diagnosis of tandem occlusions.
Materials and methods Consecutive patients with acute middle cerebral artery (MCA) occlusions who underwent endovascular
treatment were identified from our registry of neuroendovascular interventions. Thrombus attenuations of the affected MCA and
contralateral vessel were measured by NCCT. To compare individual baseline blood attenuations, the difference between the
thrombus attenuation and the contralateral MCA attenuation (referred to as ΔTM) was calculated.
Results Three hundred and twenty-five patients were included. There was a highly significant difference between mean thrombus
attenuation with isolated MCA occlusion and additional extracranial internal carotid artery (ICA) occlusion (49.9 ± 8 vs. 56.2 ±
10 Hounsfield units (HU); P < 0.001). The area under the receiver operating characteristic curve of ΔTM was 0.72. The optimal
threshold value was 13.5 HU, with a sensitivity of 67.5% and a specificity of 68.6%.
Conclusion Despite a significant difference in thrombus attenuation in MCA occlusions with an additional extracranial ICA
occlusion compared with isolated MCA occlusions, a relevant threshold of thrombus attenuation was not found
Treatment of experimental aneurysms with a GPX embolic agent prototype: preliminary angiographic and histological results
Background Recently, liquid embolic agents have
emerged for the endovascular treatment of cerebral
aneurysms. Here we describe the in vivo performance of
a novel liquid embolization agent (GPX Embolic Device).
Methods Elastase-induced aneurysms were embolized
with a GPX prototype under balloon assistance. Digital
subtraction angiography was performed pre-deployment
and immediately after, and at 5, 10, and 30min postdeployment in 10 rabbits and at 1month in 8 rabbits. The
early post-deployment intra-aneurysmal flow was graded
as unchanged, moderately diminished, or completely
absent. At 1month the status of aneurysm occlusion was
evaluated. Adhesion to catheter material and migration
of GPX was assessed.
Results The mean aneurysm neck diameter, width, and
height were 3.6±1.0mm, 3.0±0.8mm, and 7.4±1.4mm,
respectively. The mean dome-to-neck ratio was 0.9±0.2.
Complete stagnation of intra-aneurysmal flow was
observed in 9 of 10 aneurysms (90%) within 30min of
device deployment. One aneurysm showed moderately
diminished intra-aneurysmal flow at 30min. At 1month,
8 aneurysms were completely occluded. There was no
evidence of GPX adhesion to the catheter material.
Histologically, a leukocyte and foreign body reaction to
GPX was detectable 28 days after embolization.
Conclusions This is the first preclinical study reporting
the performance of a protype version of the GPX Embolic
Device in a wide-neck aneurysm model. GPX showed
promising results by achieving and maintaining high
rates of complete angiographic occlusion, but may
induce an inflammatory reaction
Why we fail: mechanisms and co-factors of unsuccessful thrombectomy in acute ischemic stroke
Purpose Mechanical thrombectomy (MT) is an effective treatment for patients suffering from acute ischemic stroke. However,
recanalization fails in about 16.5% of interventions. We report our experience with unsuccessful MT and analyze technical
reasons plus patient-related parameters for failure.
Methods Five hundred ninety-six patients with acute ischemic stroke in the anterior circulation and intention to perform MT with
an aspiration catheter and/or stent retriever were analyzed. Failure was defined as 0, 1, or 2a on the mTICI scale. Patients with
failing MT were analyzed for interventional progress and compared to patients with successful intervention, whereby parameters
included demographics, medical history, stroke presentation, and treatment.
Results One hundred of the 596 (16.8%) interventions failed. In 20 cases, thrombus could not be accessed or passed with the
device. Peripheral arterial occlusive disease is common in those patients. In 80 patients, true stent retriever failure occurred. In this
group, coagulation disorders are associated with poor results, whereas atrial fibrillation is associated with success.
The administration of intravenous thrombolysis and intake of nitric oxide donors are associated with recanalization success.
Intervention duration was significantly longer in the failing group.
Conclusion In 20% of failing MT, thrombus cannot be reached/passed. Direct carotid puncture or surgical arterial access could be
considered in these cases.
In 80% of failing interventions, thrombus can be passed with the device, but the occluded vessel cannot be recanalized. Rescue
techniques can be an option. Development of new devices and techniques is necessary to improve recanalization rates.
Assessment of pre-existing illness could sensitize for occurring complications
Different Rescue Approaches of Migrated Woven Endobridge (WEB) Devices: an Animal Study
Purpose Treatment of wide-necked intracranial aneurysms using the Woven Endobridge (WEB) device has become
broadly accepted. Feared complications with the potential of increased poor clinical outcome include dislocations and
migration of the device. This study was carried out to determine the effectiveness of a variety of different strategies to
rescue migrated WEB devices.
Methods In a porcine model, WEB devices of different sizes (SL [single layer] 3.5 Ă— 2mm and SL 4.0 Ă— 3mm, SL 8 Ă— 5mm
and SLS 8mm [single layer spherical]) were placed into both the subclavian and axillary arteries. A total of 32 rescue
maneuvers (8 per rescue device) were performed. Small WEBs were rescued using reperfusion catheters (RC) (SOFIA Plus
and JET 7), larger WEBs were rescued using dedicated rescue devices (Microsnare and Alligator). Rescue rates, times,
attempts and complications were assessed.
Results Rescue attempts of migrated WEBs were successful in all cases (100%). Rescue time (p= 0.421) and attempts
(p= 0.619) of small WEBs using RCs were comparable without significant differences. Aspiration alone was not successful
for larger WEBs. Rescue of larger WEBs was slightly faster (122.75 ± 41.15 s vs. 137.50 ± 54.46 s) with fewer attempts (1
vs. 1.37) when using the Microsnare compared to the Alligator device. Complications such as entrapment of the WEB in
the RCs, vasospasm, perforation, or dissection were not observed.
Conclusion Rescue of migrated WEB devices is a feasible and effective method and 100% successful rescue rates and
appropriate rescue times can be achieved for small WEBs using RCs and for larger WEBs using dedicated rescue devices
(Microsnare and Alligator)
Solitaire Stentectomy Using a Stent-Retriever Technique in a Porcine Model
Purpose
Mechanical thrombectomy using the Solitaire device has become a standard treatment of ischemic stroke due to large vessel occlusions. Inadvertent detachment is a feared complication, which is associated with poor clinical outcome. The aim of this experimental study was to assess in a porcine model the feasibility and effectiveness of rescuing detached Solitaire devices using different stent retrievers.
Methods
Solitaire FR devices (4 × 15/20 mm and 6 × 20/30 mm) were placed in the axillary artery of pigs. By means of 3 different stent retrievers (Trevo ProVue; EmboTrap II revascularization device; 3D revascularization device) a total of 24 rescue maneuvers (8 per retriever) were performed by deploying the retrievers within the deployed Solitaire devices and trapping parts of the Solitaire within the microcatheter. Rescue rates, rescue time and complications were assessed.
Results
Overall stentectomy of the Solitaire devices was successful in all cases (100%). Time of rescue was comparable using the applied stent retrievers (Trevo ProVue; EmboTrap II revascularization device; 3D revascularization device). Complications, such as entrapment of the Solitaire-retriever complex at the intermediate catheter, Solitaire migration, vasospasm, perforation, or dissection were not observed.
Conclusion
Stentectomy of inadvertently detached Solitaire devices using different stent retrievers is a feasible and effective method. Rescue rates and times with the Trevo ProVue, EmboTrap II and 3D revascularization device were comparable
Vascular Response on a Novel Fibrin-Based Coated Flow Diverter
Purpose
Due to thromboembolic complications and in-stent-stenosis after flow diverter (FD) treatment, the long-term use of dual antiplatelet treatment (DAPT) is mandatory. The tested nano-coating has been shown to reduce material thrombogenicity and promote endothelial cell proliferation in vitro. We compared the biocompatibility of coated (Derivo Heal) and non-coated (Derivo bare) FDs with DAPT in an animal model.
Methods
Derivo® bare (n = 10) and Derivo® Heal (n = 10) FD were implanted in the common carotid arteries (CCAs) of New Zealand white rabbits. One additional FD, alternately a Derivo bare (n = 5) or Derivo Heal (n = 5), was implanted in the abdominal aorta (AA) for assessment of the patency of branch arteries. Histopathological examinations were performed after 28 days. Angiography was performed before and after FD implantation and at follow-up.
Results
Statistical analysis of the included specimens showed complete endothelialization of all FDs with no significant differences in neointima thickness between Derivo® bare and Derivo® Heal (CCA: p = 0.91; AA: p = 0.59). A significantly reduced number of macrophages in the vessel wall of the Derivo Heal was observed for the CCA (p = 0.02), and significantly reduced fibrin and platelet deposition on the surface of the Derivo Heal was observed for the AA. All branch arteries of the stented aorta remained patent.
Conclusion
In this animal model, the novel fibrin-based coated FD showed a similar blood and tissue compatibility as the non-coated FD
Historische und aktuelle Probleme deutscher Fernsehunterhaltung
Der Beitrag gibt AusfĂĽhtrungen zu folgenden Punkten: Unterhaltung im Nachkriegsdeutschland, die goldenen Jahre der Fernsehunterhaltung, Diversifikationen in der Fernsehunterhaltung und die Zukunft der Fernsehunterhaltung unter den Bedingungen der Digitalisierung