Permanent Vessel Occlusion Research Articles

"Insights into vessel perforations during thrombectomy: Characteristics of a severe complication and the effect of thrombolysis".

Thrombectomy complications remain poorly explored. This study aims to characterize periprocedural intracranial vessel perforation including the effect of thrombolysis on patient outcomes. In this multicenter retrospective cohort study, consecutive patients with vessel perforation during thrombectomy between January 2015 and April 2023 were included. Vessel perforation was defined as active extravasation on digital subtraction angiography. The primary outcome was modified Rankin Scale (mRS) at 90 days. Factors associated with the primary outcome were assessed using proportional odds models. 459 patients with vessel perforation were included (mean age 72.5 ± 13.6 years, 59% female, 41% received thrombolysis). Mortality at 90 days was 51.9% and 16.3% of patients reached mRS 0-2 at 90 days. Thrombolysis was not associated with worse outcome at 90 days. Perforation of a large vessel (LV) as opposed to medium/distal vessel perforation was independently associated with worse outcome at 90 days (aOR 1.709, p = 0.04) and LV perforation was associated with poorer survival probability (HR 1.389, p = 0.021). Patients with active bleeding >20 min had worse survival probability, too (HR 1.797, p = 0.009). Thrombolysis was not associated with longer bleeding duration. Bleeding cessation was achieved faster by permanent vessel occlusion compared to temporary measures (median difference: 4 min, p < 0.001). Vessel perforation during thrombectomy is a severe and frequently fatal complication. This study does not suggest that thrombolysis significantly attributes to worse prognosis. Prompt cessation of active bleeding within 20 min is critical, emphasizing the need for interventionalists to be trained in complication management.

Stable Gastric Pentadecapeptide BPC 157-Possible Novel Therapy of Glaucoma and Other Ocular Conditions.

Recently, stable gastric pentadecapeptide BPC 157 therapy by activation of collateral pathways counteracted various occlusion/occlusion-like syndromes, vascular, and multiorgan failure, and blood pressure disturbances in rats with permanent major vessel occlusion and similar procedures disabling endothelium function. Thereby, we revealed BPC 157 cytoprotective therapy with strong vascular rescuing capabilities in glaucoma therapy. With these capabilities, BPC 157 therapy can recover glaucomatous rats, normalize intraocular pressure, maintain retinal integrity, recover pupil function, recover retinal ischemia, and corneal injuries (i.e., maintained transparency after complete corneal abrasion, corneal ulceration, and counteracted dry eye after lacrimal gland removal or corneal insensitivity). The most important point is that in glaucomatous rats (three of four episcleral veins cauterized) with high intraocular pressure, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, nor- mal retinal and choroidal blood vessel presentation, and normal optic nerve presentation. The one episcleral vein rapidly upgraded to accomplish all functions in glaucomatous rats may correspond with occlusion/occlusion-like syndromes of the activated rescuing collateral pathway (azygos vein direct blood flow delivery). Normalized intraocular pressure in glaucomatous rats corresponded to the counteracted intra-cranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension in occlusion/occlusion-like syndromes, were all attenuated/eliminated by BPC 157 therapy. Furthermore, given in other eye disturbances (i.e., retinal ischemia), BPC 157 instantly breaks a noxious chain of events, both at an early stage and an already advanced stage. Thus, we further advocate BPC 157 as a therapeutic agent in ocular disease.

Transient cerebral ischemia induces the neuroglial proliferative activity and the potential to redirect neuroglial differentiation

Brain injury triggers a complex response involving morphological changes, cellular proliferation, and differentiation of newly formed neuroglial subpopulations. These processes have been extensively studied in animal stroke models with permanent large vessel occlusion. However, less is known about neuroglial response after transient cerebral ischemia. Herein, we aimed to determine an astrocytic and NG2 glial proliferative response, potential changes in expression of developmental neuroglial markers: vimentin, nestin, oligodendrocyte transcription marker (Olig2), and a role of neuroglial subpopulations as a source of cells replenishing structural deficiencies in the ischemic brain. Results showed an induction of a proliferative neuroglial response in the peri-infarct area reflected in an increased percentage of GFAP/Ki67 + and NG2/Ki67 + cells within 4 weeks after transient MCAO. The peak of GFAP+ astrocytes proliferation of 30.3 ± 10.3% was observed in the first week, and a peak of NG2 + cells proliferation of 23.1 ± 11.8% in the second week after stroke. The presence of GFAP/Vimentin+ and GFAP/Nestin+ cells, as well as GFAP/Olig2 + and NG2/Olig2 + cells indicated an induction of developmental phenotypes with a differentiation potential. Finally, observed between day 1 and week 3 transient GFAP/NG2 + colocalization suggests the heterogeneous source of the reactive neuroglia after transient MCAO. Altogether, one-hour MCAO is a sufficient pathological stimulus to trigger a strong proliferative response of GFAP+ and NG2 + neuroglial cells and induce their early developmental phenotype. Our results suggest that transient ischemia may initiate a change in the direction of differentiation within the neuroglia cell population.

Intracranial stenting as a bail-out option for posthemorrhagic cerebral vasospasm: a single-center experience with long-term follow-up

BackgroundCerebral vasospasm (CVS) is a leading cause of morbidity and mortality in patients after aneurysmal subarachnoid hemorrhage (aSAH). Endovascular treatment, including intraarterial infusion of drugs with vasodilation effects, and balloon- and stentriever angioplasty, are helpful but may achieve only short-term effects. There is a clinical need for long-lasting treatment of refractory recurrent vasospasm. We report our experience in stent implantation as a treatment for recurrent severe post-SAH vasospasm.MethodsA retrospective analysis of our institutional database of 883 patients with SAH, managed between January 2010 and December 2021, was performed. Six patients were identified as having received intracranial stenting in the context of post-SAH cerebral vasospasm. All patients were initially treated with intra-arterial infusion of nimodipine and/or milrinone. Self-expanding intracranial stents were implanted during endovascular aneurysm treatment to enable access despite impaired perfusion (Group 1) or as a bail-out strategy after failed intraarterial drug infusion or mechanical treatment (Group 2). All stented patients received dual antiplatelet therapy (DAPT) for 6 months.ResultsNine vessels in six patients with severe post-SAH vasospasm were stented. The stents were deployed in 16 vessel segments. All attempted implantations were technically successful. All patients demonstrated radiographic and clinical improvement of the vessel narrowing. No recurrent vasospasm or permanent vessel occlusion of the stented vessels was encountered. A thrombus formation in a Group 1 patient resolved under 4 mg eptifibatide IA infusion. During long-term angiographic follow-up, neither in-stent stenosis nor stent occlusion was found.ConclusionsEndovascular implantation of self-expanding stents is a potential ultima ratio strategy for patients with severe refractory post-SAH cerebral vasospasm. Stents with reduced thrombogenicity (avoiding DAPT) and bioabsorbable self-expanding stents might further advance this concept.

Pseudo-continuous arterial spin labeling with short post-labeling delay time sensitively reflects the hemodynamics of symptomatic patients with permanent large vessel occlusion before and after revascularization.

This study evaluated the feasibility of arterial spin labeling (ASL) for diagnosing hemodynamic stroke due to permanent anterior circulation large vessel occlusion. Three-dimensional pseudo-continuous ASL data at two post-labeling delay (PLD) times (1.5 and 2.5s) in patients with unilateral permanent middle cerebral artery (MCA) segment 1 (M1) or internal cerebral artery (ICA) occlusion were acquired during routine magnetic resonance angiography. Sixty-one patients with symptomatic occlusion (M1, 24; ICA, 37) and 69 patients with asymptomatic occlusion (M1, 21; ICA, 48) were enrolled. Regions of interest were automatically placed in the MCA region using a template. The respective scans were compared with asymptomatic M1 or ICA occlusion scans. The ratio of signal intensity (occlusion side/non-occlusion side) in the perfusion area of MCA (asymmetry index [AI]) was compared between both groups. In both PLD groups, AI was significantly lower in symptomatic patients than in asymptomatic patients. The receiver operating characteristic curve showed moderate capacity for the prediction of symptomatic AI in both groups (area under the curve, 0.739 and 0.712, respectively). As a result of extracranial-intracranial bypass operation in 28 symptomatic (M1, eight; ICA, 20) patients, AI was significantly higher postoperatively in the PLD 1.5s group than in the PLD 2.5s group. In symptomatic patients with permanent large vessel occlusion, the signal intensity ratio of pseudo-continuous ASL with short PLD sensitively reflects the hemodynamics before and after revascularization; therefore, this technique may be an alternative method in situations where PET or SPECT cannot be performed.

Endovascular treatment of middle cerebral artery aneurysms: A single center experience with a focus on thromboembolic complications.

Background Endovascular treatment of middle cerebral artery (MCA) aneurysms has traditionally been considered difficult due to complex branching patterns, frequent involvement of parent vessels within the aneurysm neck, and a high incidence of thromboembolic complications. Methods The cases of 93 MCA aneurysms treated with endovascular intervention at our institution between 2003 and 2015 were retrospectively reviewed. Demographic, clinical, and radiographic variables were recorded and analyzed. Results Immediate complete or near-complete occlusion was achieved in 81 (90%) cases. At the longest follow up of 6 months or greater, 83.3% of the aneurysms were stable-to-improved in the Raymond occlusion classification, 8.3% were found to have minor recanalization not requiring retreatment, and 8.3% required retreatment due to significant recanalization. Thromboembolic events occurred in 18 (19.3%) of cases, but only 1 resulted in permanent vessel occlusion and only 1 resulted in permanent neurologic impairment. Thrombus was resolved with intra-arterial thrombolysis or mechanical thrombectomy in 17 of the 18 cases. There were only two cases resulting in morbidity (2.15%). There was no statistically significant correlation between aneurysm location, size, morphology, or use of adjuvant device with radiographic outcome or thromboembolic event. Conclusions While the rate of thromboembolic events in our series was 19%, the overall morbidity was only 2%. This highlights the fact that even complex MCA aneurysms can safely and effectively be treated by endovascular means with or without the use of balloon or stent assistance, as long as the interventionalist is astutely aware of the possibility of thrombus formation and acts accordingly with thrombolytic therapy when necessary.

Successful use of recombinant tissue plasminogen activator (r-TPA) for management of chylothorax associated with central venous thrombosis after neonatal cardiac surgery

Postoperative chylothorax is a frequently encountered pathology occurring in up to 5% of patients undergoing surgery for repair of congenital heart disease. Neck vein thrombosis can be associated with chylothorax and may contribute to its severity and duration. Furthermore, neck vessel thrombosis resulting in permanent vessel occlusion may hinder future management, diagnostic studies and cardio-surgical interventions. In this report we are describing a neonate who developed chylothorax on the 7th post-operative day following open-heart surgery. The chylothorax was linked to venous thrombosis in the cannulated right internal jugular vein with thrombus extending to the right atrium. After using low dose tissue plasminogen activator (r-TPA) infusion, the thrombi disappeared and the chylothorax resolved with no complications.

4:18 PM Abstract No. 174 - Angiographic features and endovascular management of carotid blowout syndrome in patients with nasopharyngeal carcinoma treated with radiotherapy - a review of 12-years experience

Purpose Our 12-years experience in the management of Carotid blowout syndrome (CBS) in patients with nasopharyngeal carcinoma (NPC) treated with radiotherapy (RT) was reviewed. Special emphasis was made on the angiographic findings and management approaches. Materials and Methods 14 patients with RT-treated NPC underwent Digital Subtraction Angiography (DSA) from 2000 to 2012 for management of CBS were retrospectively reviewed. The affected arterial segments, number and size of pseudoaneurysms were analyzed. The management approachs and clinical outcomes were also assessed. Results 16 DSAs were performed on 14 patients presented with acute CBS. Pseudoaneurysms were identified in 11 patients (79%) while 3 others (21%) showed active extravasation. CBS was more common in internal carotid artery (n=9, 64%) than external carotid artery (n=5, 36%). Petrous segment of ICA was the most commonly involved segment (n=5, 36%), followed by cervical segment of ICA (n=4, 29%) and maxillary artery (n=3, 21%). The maximum diameter of the pseudoaneurysms ranged from 2.3mm to 34.3mm (mean = 11.3mm). Permanent vessel occlusions or placements of covered stent were performed on 11 patients (79%). Majority (n=8, 73%) were treated with permanent vessel occlusion by either coils (n=5, 62%) or gelfoams (n=3, 38%). Gelfoam embolizations were performed in the terminal branches of maxillary, facial and mandibular arteries. Covered stents were placed in the remaining 3 patients (27%) and all had lesions in the petrous segment of ICA. Immediate hemostasis was achieved in all patients and no lethal complication was reported. Interval follow-up of 3 months showed no recurrence of CBS in all cases. Conservative management was adopted in 3 patients (21%) due to poor premorbid condition and occluded bilateral ICAs. All passed away within one week following initial diagnostic DSA. Conclusion Carotid blowout syndrome in patients with RT-treated NPC most commonly involved petrous segment of ICA. Pseudoaneurysms were identified in most cases of CBS. Both permanent vessel occlusions and placement of covered stents could achieve immediate hemostasis with no lethal complication in all our study subjects.

Le modafinil améliore les performances de conduite simulée des malades souffrant d’hypersomnie : étude randomisée placebo-verum

To report a novel technique for temporary and permanent vessel occlusion with a single microcatheter and investigate its efficacy in endovascular management of cerebral aneurysms and invasive head and neck tumors.A 58-year-old woman with a history of T3N0 squamous cell carcinoma of the tongue with extensive surgical resections and radiotherapy presented to the emergency department with further wound dehiscence and exposure of the left cervical internal carotid artery (ICA). Digital subtraction angiography (DSA) was performed with the patient under conscious sedation. An Ascent balloon, 4 mm × 15 mm, was prepared and introduced into the proximal ICA. While the patient was fully awake, temporary balloon occlusion (TBO) was performed for 30 minutes. The Ascent balloon was kept inflated. Through the inflated Ascent balloon, coil embolization of the proximal ICA was initiated. The interstices of the coils were filled with Onyx 18 and Onyx 34 liquid embolic agents (ev3 Neurovascular, Inc, Irvine, California, USA).The Ascent balloon can be used as a temporary balloon device and as a coil or Onyx embolization device. As a result, fewer catheters, guidewires, and balloon inflations and deflations are required for the procedure, which is both cost-effective and time-efficient. The combination of initial coiling to create a framework for the deconstruction with a liquid embolic agent (Onyx) is a safe and efficient technique for vessel deconstruction. Flow arrest with proximal balloon occlusion minimizes the risks of distal thromboembolic events during embolization.This novel technique for temporary and permanent vessel occlusion with a single microcatheter is both cost-effective and time-efficient.

A Surgical Model of Permanent and Transient Middle Cerebral Artery Stroke in the Sheep

BackgroundAnimal models are essential to study the pathophysiological changes associated with focal occlusive stroke and to investigate novel therapies. Currently used rodent models have yielded little clinical success, however large animal models may provide a more suitable alternative to improve clinical translation. We sought to develop a model of acute proximal middle cerebral artery (MCA) ischemic stroke in sheep, including both permanent occlusion and transient occlusion with reperfusion.Materials and Methods18 adult male and female Merino sheep were randomly allocated to one of three groups (n = 6/gp): 1) sham surgery; 2) permanent proximal MCA occlusion (MCAO); or 3) temporary MCAO with aneurysm clip. All animals had invasive arterial blood pressure, intracranial pressure and brain tissue oxygen monitoring. At 4 h following vessel occlusion or sham surgery animals were killed by perfusion fixation. Brains were processed for histopathological examination and infarct area determination. 6 further animals were randomized to either permanent (n = 3) or temporary MCAO (n = 3) and then had magnetic resonance imaging (MRI) at 4 h after MCAO.ResultsEvidence of ischemic injury in an MCA distribution was seen in all stroke animals. The ischemic lesion area was significantly larger after permanent (28.8%) compared with temporary MCAO (14.6%). Sham animals demonstrated no evidence of ischemic injury. There was a significant reduction in brain tissue oxygen partial pressure after permanent vessel occlusion between 30 and 210 mins after MCAO. MRI at 4 h demonstrated complete proximal MCA occlusion in the permanent MCAO animals with a diffusion deficit involving the whole right MCA territory, whereas temporary MCAO animals demonstrated MRA evidence of flow within the right MCA and smaller predominantly cortical diffusion deficits.ConclusionsProximal MCAO can be achieved in an ovine model of stroke via a surgical approach. Permanent occlusion creates larger infarct volumes, however aneurysm clip application allows for reperfusion.

Neuroradiologische Diagnostik und Interventionen bei Prozessen an der Schädelbasis

Besides image-guided biopsy techniques, the emphasis in the interdisciplinary cooperation between head and neck surgery and neuroradiology is on vessel-occluding and preserving measures. Knowledge of dangerous anastomoses between extracranial and intracranial vessels is crucial. The principles of vessel-occluding procedures including materials are presented and illustrated with case examples. Embolization of glomus tumors or epistaxis and preoperative permanent vessel occlusion techniques are demonstrated as well as vessel-preserving therapies, such as placement of covered stents for improving tumor resectability or after iatrogenic laceration of the internal carotid artery.

Endovascular treatment paradigm of carotid blowout syndrome: Review of 8-years experience

ObjectivesEndovascular treatment is effective in treating carotid blowout syndrome (CBS). We reviewed our experience in addressing CBS over eight years and presented an account of the treatment paradigm and management algorithm. MethodAll cases of CBS from 2003 to 2010 with endovascular treatment performed in our center were reviewed. 15 CBS in 14 patients were recruited. Based on our management algorithm, treatment regimen was stratified into deconstructive or constructive methods. Their clinical presentations, angiographic features, angiographic and clinical outcomes were reviewed. Results10 patients were treated with deconstructive method by means of permanent vessel occlusion (PVO) and 4 patients were treated with constructive method by means of placement of covered stent (n=3) or flow diverting device (n=1). Immediate hemostasis was achieved in all cases. 7 (50%) patients, in whom 5 treated with PVO and 2 with covered stent, had favorable outcomes and survived at a median follow-up period of 4 months (range: 1–84 months). ConclusionPermanent vessel occlusion remains the gold standard of treatment and tends to show a favorable long-term outcome. Off-label use of covered stent and flow-diverting device can produce satisfactory results should balloon occlusion test fail, but long-term follow up would be required for definitive assessment.

Drug-Eluting Introducer Sheath Prevents Local Peripheral Complications: Pre-Clinical Evaluation of Nitric Oxide–Coated Sheath

This study evaluated the protective effect of nitric oxide-coating of introducer sheath on the local complications in juvenile porcine femoral arteries with similar size to human radial arteries. Insertion of an introducer sheath induces vasospasm and transient or permanent vessel occlusion of radial arteries. Nitric oxide-coated or control introducer sheaths with or without spasmolytic cocktail (control + C-sheath) were inserted into porcine femoral arteries, followed by percutaneous coronary intervention (PCI). The diameter of the femoral artery at the puncture site, distally and proximally, was measured by quantitative angiography. Histopathological and histomorphometric parameters of the femoral arteries were analyzed 1 h or 1 week after PCI. Insertion of femoral sheath led to mild or severe spasms, with significantly higher vessel diameter at the access site (2.69 ± 0.81 mm vs. 1.77 ± 0.77 mm and 1.85 ± 0.66 mm, p < 0.001), and proximal and distal to it, during PCI in the nitric oxide-sheath group versus the control-sheath and control + C-sheath groups, respectively. Immediately following PCI, significantly less luminal thrombosis (12% vs. 33% and 31% of all analyzed segments, p < 0.001) was observed in the nitric oxide-sheath arteries. At 1 week, lower intimal inflammation score (0.43 ± 11 vs. 1.03 ± 0.35 and 1.04 ± 0.32, p < 0.05), less luminal thrombosis (8% vs. 21% and 30% p < 0.05), and smaller intimal hyperplasia (0.31 ± 0.31 mm(2) vs. 0.47 ± 1.00 mm(2) and 0.86 ± 0.82 mm(2), p < 0.05) were observed in NO-sheath arteries at the injury site. Nitric oxide coating on the introducer sheath prevents local complications during PCI and results in less vascular thrombosis and inflammation at the access site, contributing to patency of the access vessel with similar size to the radial artery.

‘Salvaged’ Stroke Ischaemic Penumbra Shows Significant Injury: Studies with the Hypoxia Tracer FMISO

The degree of cellular injury within the stroke ischaemic penumbra is controversial. Clinical and experimental studies using the hypoxia tracer fluoromisonidazole (FMISO) have shown retention of this tracer in the penumbra, but cellular outcome has not been well characterised. We hypothesised that macroscopically intact FMISO-retaining penumbral tissues would show evidence of microscopic injury, and that no FMISO retention would be seen in the infarct core. To determine the distribution of FMISO retention, a tritium-labelled tracer (hydrogen-3 FMISO ([(3)H]FMISO)) was administered 5 minutes after induction of 2-hour temporary middle cerebral artery occlusion. Coregistered brain histology and autoradiography at 24 hours revealed marked retention of FMISO within the infarct. However, 48% of the FMISO-retaining tissue was not infarcted. Within this noninfarcted tissue, only 27% (17 of 64) of sampled regions showed no evidence of neuronal loss, whereas 44% (28 of 64) showed injury to >50% of neurons within the sample. To determine whether FMISO retention occurred after the tissue was already committed to infarction, FMISO was administered 4 to 6 hours after the onset of permanent vessel occlusion. Intense FMISO retention was consistently seen throughout the infarct core. In conclusion, FMISO retention occurs both within the ischaemic penumbra and within the early infarct core. Most penumbral tissues show evidence of selective cellular injury.

Effectiveness of PSD95 Inhibitors in Permanent and Transient Focal Ischemia in the Rat

Postsynaptic density-95 inhibitors reduce ischemic brain damage without inhibiting excitatory neurotransmission, circumventing the negative consequences of glutamatergic inhibition. However, their efficacy in permanent ischemia and in providing permanent neuroprotection and neurobehavioral improvement in a practical therapeutic window is unproven. These were tested here under conditions that included fever, which is a common occurrence in clinical stroke. Six studies were performed in unfasted Sprague-Dawley rats. Two involved permanent pial vessel occlusion in male and female rats. Two involved permanent middle cerebral artery occlusion, which induced severe hyperthermia, and 2 involved transient middle cerebral artery occlusion. Animals were treated with a single intravenous injection of postsynaptic density-95 inhibitors (Tat-NR2B9c([SDV]) or Tat-NR2B9c([TDV])) 1 hour or 3 hours after stroke. Infarct volumes and neurobehavior were assessed in a blinded manner at 24 hours (pial vessel occlusion and permanent middle cerebral artery occlusion) or at 62 days (transient middle cerebral artery occlusion). Postsynaptic density-95 inhibitors dramatically reduced infarct size in male and female animals exposed to pial vessel occlusion (>50%), in hyperthermic animals with fever exceeding 39 degrees C exposed to permanent middle cerebral artery occlusion (approximately 50%), and at 62 days poststroke in animals exposed to transient middle cerebral artery occlusion (approximately 80%). Effectiveness of postsynaptic density-95 inhibitors was achieved without the drugs affecting body temperature. In transient middle cerebral artery occlusion, a single dose of postsynaptic density-95 inhibitor given 3 hours after stroke onset permanently maintained reduced infarct size and improved neurobehavior. Postsynaptic density-95 inhibitors administrated 3 hours after stroke onset reduced infarct volumes and improved long-term neurobehavioral functions in a wide therapeutic window. This raises the possibility that they may have future clinical usefulness.

Bronchial artery embolization with detachable coils for the treatment of haemoptysis. Preliminary experience

This paper reports our early experience in the treatment of haemoptysis with embolization of the bronchial arteries using detachable coils. Ten patients (mean age 45 years, range 23-83) with haemoptysis due to bronchoscopic biopsy of indeterminate lung nodules, lung cancer, tubercular bronchiectasis, cystic bronchiectasis or sarcoidosis underwent embolization of the bronchial arteries responsible for the bleeding using detachable coils. Patients were followed-up for a median of 14 months. In all patients the procedure halted the bronchial bleeding within 24 hours. Eight patients had no recurrence of haemoptysis. In one patient with lung cancer and another with sarcoidosis, haemoptysis recurred within 1-3 months due to recruitment of additional feeding arteries and to a missed large feeding artery originating from the subclavian artery, which required a new procedure. Use of detachable coils for embolization of bronchial arteries in patients with haemoptysis is advantageous since it eliminates the risk of migration typical of other embolic materials and enables rapid and permanent vessel occlusion.

Monitoring of motor evoked potentials compared with somatosensory evoked potentials and microvascular Doppler ultrasonography in cerebral aneurysm surgery.

The aims of this study were to compare the efficiency of motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), and microvascular Doppler ultrasonography (MDU) in the detection of impending motor impairment from subcortical ischemia in aneurysm surgery; to determine their sensitivity for specific intraoperative events; and to compare their impact on the surgical strategy used. Motor evoked potentials, SSEPs, and MDU were monitored during 100 operations for 129 aneurysms in 95 patients. Intraoperative events, monitoring results, and clinical outcome were correlated in a prospective observational design. Motor evoked potentials indicated inadequate temporary clipping, inadvertent occlusion, inadequate retraction, vasospasm, or compromise to perforating vessels in 21 of 33 instances and deteriorated despite stable SSEPs in 18 cases. Microvascular Doppler ultrasonography revealed inadvertent vessel occlusion in eight of 10 cases and insufficient clipping in four of four cases. Stable evoked potentials (EPs) allowed safe, permanent vessel occlusion or narrowing despite reduced flow on MDU in five cases. Two patients sustained permanent and 10 showed transient new weakness, which had been detected by SSEPs in two of 12 patients and MEPs in 10 of 11 monitored cases. The surgical strategy was directly altered in 33 instances: by MEPs in 16, SSEPs in four, and MDU in 13. Monitoring of MEPs is superior to SSEP monitoring and MDU in detecting motor impairment, particularly that from subcortical ischemia. Microvascular Doppler ultrasonography is superior to EP monitoring in detecting inadvertent vessel occlusion, but cannot assess remote collateral flow. Motor evoked potentials are most sensitive to all other intraoperative conditions and have a direct influence on the course of surgery in the majority of events. A controlled study design is required to confirm the positive effect of monitoring on clinical outcome in aneurysm surgery.

Pronounced arterial collateralization was induced after permanent rat cerebral four-vessel occlusion. Relation to neuropathology and capillary ultrastructure.

The present study investigates chronic changes in cerebral arterial vessel system, microvasculature, and brain histopathology using an adult rat model based on permanent and stepwise occlusion of four cerebral vessels. Digital subtraction angiography (DSA) was performed to study chronic changes in arterial cerebral vessel system after permanent vessel occlusion. Long-lasting functional changes such as NMDA-, AMPA- and GABA(A)-receptor binding were detected in hippocampus and dentate gyrus using autoradiography. Structural changes in cerebral capillaries were investigated using light- and electron microscopy. Chronic cerebral oligemia did not cause any significant changes in the densities of excitatory glutamate and inhibitory GABA(A) receptors. By electron microscopy we could document, however, that most capillaries in vessel-occluded animals shrank, the endothelial cells were prominent with enlarged nuclei and increased cytoplasm, and the basal membrane was thickened. In contrast to the degenerative changes in brain capillaries, pronounced arterial collateralization was disclosed by DSA after chronic brain vessel occlusion. The model of chronic occlusion of four cerebral vessels is characterized by capillary degeneration and arterial collateralization proceeding in parallel. Thus, this rat model may be useful in investigations of long-lasting compensatory mechanisms contributing to cerebrovascular or neurodegenerative disorders.

Temporary arterial occlusion in the repair of ruptured intracranial aneurysms: an analysis of risk factors for stroke.

This study was performed to further elucidate technical and patient-specific risk factors for perioperative stroke in patients undergoing temporary arterial occlusion during the surgical repair of their aneurysms. One hundred twelve consecutive patients in whom temporary arterial occlusion was performed during surgical repair of an aneurysm were retrospectively analyzed. Confounding factors (inadvertent permanent vessel occlusion and retraction injury) were identified in six cases (5%) and these were excluded from further analysis. The demographics for the remaining 106 patients were analyzed with respect to age, neurological status, aneurysm characteristics, intraoperative rupture, duration of temporary occlusion, and number of occlusive episodes; end points considered were outcome at 3-month follow up and symptomatic and radiological stroke. Overall 17% of patients experienced symptomatic stroke and 26% had radiological evidence of stroke attributable to temporary arterial occlusion. A longer duration of clip placement, older patient age, a poor clinical grade (Hunt and Hess Grades IV-V), early surgery, and the use of single prolonged clip placement rather than repeated shorter episodes were associated with a higher risk of stroke based on univariate analysis. Intraoperative aneurysm rupture did not affect stroke risk. On multivariate analysis, only poorer clinical grade (p = 0.001) and increasing age (p = 0.04) were significantly associated with symptomatic stroke risk.

A novel method of intra-hepatic bile-duct closure using the LigaSure device

The LigaSure Vessel Sealing System is an energy-based haemostatic tool that produces permanent vessel occlusion. It was developed as an alternative method for ligating vascular bundles quickly and reliably during surgery. This study demonstrates its efficacy on intra-hepatic bile ducts in a porcine in vitro model.