Abstract TP133: Efficacy Of Mechanical Thrombectomy For The Posterior Circulation Stroke

Background and Purpose: The efficacy of mechanical thrombectomy (MT) for posterior circulation large vessel occlusions has not been fully elucidated. We investigated the efficacy and safety of MT for posterior circulation stroke (PCS) compared with anterior circulation stroke (ACS).

Methods: We analyzed 885 consecutive patients who underwent MT for acute ischemic stroke between January 2013 and December 2020 at six comprehensive stroke centers. The patients were divided into two groups; the PCS and ACS group. The procedural and clinical outcomes were compared between the groups.

Results: A total of 767 patients (PCS group, 83; ACS group, 684), were analyzed. PCS patients were significantly younger (75 vs. 79, P = 0.008) and had a higher NIHSS score at baseline (23 vs 19, p=0.012) and longer door to puncture time (97 vs 73 min, p=0.009). The rate of male (67.0 vs 46.9% p<0.001) and atherosclerotic brain infarction (22.8 vs 8.3% p<0.001) were higher, comorbid atrial fibrillation (50.6 vs 64.4% p=0.022) was fewer in the PCA group. The rate of mTICI 3 recanalization at the first pass (40.9 vs 28.5% p=0.019) was significantly higher in the PCS group. However, the rates of final mTICI ≥ 2b recanalization (86.6 vs 83.8% p=0.491), symptomatic hemorrhagic complications, good clinical outcome at 90 days (34.3 vs 32.5% p=0.767), and mortality (22.3 vs 16% p=0.184) were similar in the groups. In the PCS group, the single use of a stent retriever for the first pass was associated with higher mortality rate compared with use of ADAPT or combined technique (38.6 vs 12.2% p=0.012).

Conclusions: MT for PCS seemed to be beneficial, having similar complication, recanalization rate, and clinical outcomes with ACS.

Abstract TMP88: Prognostic Scoring System Of Mechanical Thrombectomy For Elderly Acute Ischemic Stroke Patients

Background: The number of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) in elderly patients has increased, but the feasibility and safety are still debated. We aimed to investigate the risk factors and produce a prognostic scoring system for MT in elderly AIS patients.

Methods: We analyzed data from 763 consecutive patients who underwent MT for AIS between January 2013 and January 2020 at seven comprehensive stroke centers for derivation group. We defined elderly patients as ≥ 75 years of age. We investigated the risk factors of MT among these elderly patients and developed a prognostic scoring system assigned weighted points proportional to their standardized coefficient values. We conducted a subsequent validation study that included 287 consecutive patients treated between February 2020 and December 2021.

Results: In total, 251 elderly patients in derivation group were analyzed retrospectively. According to the multivariable analysis, we developed a scoring system (SNA 3 P score) consisting of six factors, including age ≥ 90 (2 points), female sex (2 points), a pre-modified Rankin Scale (mRS) score of 2 (1 point), anticoagulant drug use (2 points), the NIHSS score (4 points), and the ASPECTS (4 points). A score ≤ 5 predicted an mRS score of 0-2 at 90 days with a sensitivity of 74% and a specificity of 65%, and the area under the curve (AUC) was 0.76. In the validation study, a score ≤ 5 predicted an mRS score of 0-2 at 90 days with a sensitivity of 70% and a specificity of 60% (AUC was 0.74).

Conclusions: We created the novel scoring system to predict the functional outcome of elderly AIS patients undergoing MT. This simple scoring system may provide the information for indication of MT for elderly AIS patients, but further investigation for external validation is needed.

Efficacy of combined use of a stent retriever and aspiration catheter in mechanical thrombectomy for acute ischemic stroke

BACKGROUND

The efficacy of combined stent retriever (SR) and aspiration catheter (AC; combined technique: CBT) use for acute ischemic stroke (AIS) is unclear. We investigated the safety and efficacy of single-unit CBT (SCBT)-retrieving the thrombus as a single unit with SR and AC into the guide catheter-compared with single use of either SR or contact aspiration (CA).

METHODS

We analysed 763 consecutive patients who underwent mechanical thrombectomy for AIS between January 2013 and January 2020, at six comprehensive stroke centers. Patients were divided into SCBT and single device (SR/CA) groups. The successful recanalization with first pass (SRFP) and other procedural outcomes were compared between groups.

RESULTS

Overall, 240 SCBT and 301 SR/CA (SR 128, CA 173) patients were analyzed. SRFP (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2c, 43.3% vs 27.9%, p<0.001; mTICI 3, 35.8% vs 25.5%, p=0.009) and final mTICI ≥2b recanalization (89.1% vs 82.0%, p=0.020) rates were significantly higher, puncture-to-reperfusion time was shorter (median (IQR) 43 (31.5-69) vs 55 (38-82.2) min, p<0.001), and the number of passes were fewer (mean±SD 1.72±0.92 vs 1.99±1.01, p<0.001) in the SCBT group. Procedural complications were similar between the groups. In subgroup analysis, SCBT was more effective in women, cardioembolic stroke patients, and internal carotid artery and M2 occlusions.

CONCLUSIONS

SCBT increases the SRFP rate and shortens the puncture-to-reperfusion time without increasing procedural complications.

Mechanical Thrombectomy for Basilar Artery Occlusion Compared with Anterior Circulation Stroke

OBJECTIVE

To investigate the clinical effectiveness of mechanical thrombectomy (MT) for basilar artery occlusion (BAO) and to ascertain whether outcomes for patients with BAO were comparable to those with anterior circulation large vessel occlusion (ACS).

METHODS

A total of 345 patients who underwent MT between 2011 and 2018 were grouped by occlusion site (295 patients with ACS and 50 patients with BAO). Patients' baseline characteristics, procedural times, complications, symptomatic intracranial hemorrhage, modified Rankin Scale score, and mortality at 90 days were analyzed.

RESULTS

Male preponderance (66.0% vs. 48.8%; P = 0.0316), younger age (72.5 years [interquartile range (IQR), 64.75-78.5 years] vs. 77 years [IQR 69-84 years]; P = 0.0297), higher National Institutes of Health Stroke Scale score (24.5 [IQR, 13-32] vs. 18 [IQR 13-22]; P = 0.0015) and higher reperfusion rate (100% vs. 84.7%; P = 0.0010) were observed in patients with BAO. We found no significant difference in favorable outcomes (modified Rankin Scale score ≤2) between patients with BAO and patients with ACS (64.3% vs. 49.3%; P = 0.0914). In multivariate analysis, Alberta Stroke Program Early Computed Tomography Score (odds ratio [OR], 1.282; 95% confidence interval [CI], 1.090-1.524; P = 0.0024), time from onset to reperfusion (OTR) (OR, 0.9950; 95% CI, 0.992-0.998; P = 0.0008), successful reperfusion (OR, 6.953; 95% CI, 1.576-48.729; P = 0.0092), and hemorrhagic complication (OR, 0.352; 95% CI, 0.151-0.797; P = 0.0122) were associated with a favorable outcome at 90 days in patients with ACS. In patients with BAO, only OTR (OR, 0.9879; 95% CI, 0.974-0.999; P = 0.0314) was associated with a favorable outcome at 90 days.

CONCLUSIONS

MT may be considered the standard care for patients with BAO. OTR was the only common significant predictor for favorable outcomes in both patient cohorts.

A Direct Aspiration First Pass Technique in Japanese Real-World Clinical Setting

BACKGROUND

It is debatable whether mechanical thrombectomy has benefits in a real-world setting outside the more rigid and selective clinical trial environment.

OBJECTIVE

To evaluate clinical outcomes, efficacy, and safety of mechanical thrombectomy in single-center retrospective cohort case series.

METHODS

We reviewed prospectively collected data from our large-vessel occlusion stroke database to identify patients undergoing mechanical thrombectomy using Penumbra catheters (Penumbra, Almeida, California) as first-line devices. The primary outcomes were the modified Rankin Scale score at 90 d and recanalization rate. The secondary outcomes included the rates of hemorrhagic complications and mortality.

RESULTS

The entire study population included 298 patients. Thrombolysis in Cerebral Infarction Scale ≥2b was achieved in 86.6% of patients. Fifty-five patients (18.5%) were outside the 6 hr time window and 82 patients (27.5%) were over 80-yr old. The posterior circulation thrombectomy rate was 12.4%. At 90 d from onset, 49.3% of patients had favorable outcomes. The parenchymal hemorrhage type 2 (PH2) and subarachnoid hemorrhage rates were 2.3% and 11.7%, respectively. In multivariate analyses, cerebral blood flow/cerebral blood volume mismatch (odds ratio [OR] = 9.418; 95% confidence interval [CI], 3.680-27.726; P < .0001), onset to recanalization time (OR = 0.995; 95% CI, 0.991-0.998; P = .0003), and hemorrhagic complications including PH2 and subarachnoid hemorrhage (OR = 0.186; 95% CI, 0.070-0.455; P = .0002) were associated with favorable outcomes.

CONCLUSION

A direct aspiration first pass technique with an adjunctive device demonstrated high recanalization rates in old Japanese patients. Our patient cohort may reflect the application of endovascular techniques in acute ischemic stroke treatment in a real-world setting.

Subtraction of arterial spin-labeling magnetic resonance perfusion images acquired at dual post-labeling delay: Potential for evaluating cerebral hyperperfusion syndrome following carotid endarterectomy

Arterial spin-labeling magnetic resonance perfusion imaging is a promising tool for the diagnosis of cerebral hyperperfusion syndrome after carotid endarterectomy. However, arterial spin-labeling with a single post-labeling delay has been reported to show a higher incidence of increased arterial spin-labeling signals in the bilateral hemisphere, probably due to a shortening of the arterial transit time or an arterial transit artifact caused by intravascular stagnant magnetically-labeled spin. To overcome these shortcomings, we used two post-labeling delay settings (1.0 and 1.5 s) in 8 patients who had undergone carotid endarterectomy. In addition, we created a subtraction image between the mean perfusion maps at post-labeling delays of 1.0 and 1.5 s. This also decreased arterial transit artifacts, as these appeared in nearly the same configuration in both post-labeling delay settings. In all eight cases examined, increased arterial spin-labeling signals were observed bilaterally on both dual post-labeling delay settings. Subtraction images revealed that these increased signals were attributable to arterial transit artifacts in seven cases. However, in one patient who developed clinical symptoms, the subtraction method demonstrated post-carotid endarterectomy hyperperfusion. This preliminary study demonstrates that the subtraction method might decrease arterial transit artifacts and yield a map that can better represent true perfusion, thus enabling the detection of post-carotid endarterectomy hyperperfusion.

Hemodynamic state of periictal hyperperfusion revealed by arterial spin-labeling perfusion MR images with dual postlabeling delay

Background

Magnetic resonance imaging (MRI), including perfusion MRI with arterial spin labeling (ASL) and diffusion-weighted imaging (DWI), are applied in the periictal detection of circulatory and metabolic consequences associated with epilepsy. Although previous report revealed that prolonged ictal hyperperfusion on ASL can be firstly detected and cortical hyperintensity of cytotoxic edema on DWI secondarily obtained from an epileptically activated cortex, the hemodynamic state of the periictal hyperperfusion has not been fully demonstrated.

Methods study-1

We retrospectively analyzed the relationship between seizure manifestations and the development of periictal MRI findings, in Case 1 with symptomatic partial epilepsy, who underwent repeated periictal ASL/DWI examination for three epileptic ictuses (one examination for each ictus). Study-2: We evaluated the hemodynamic state of periictal hyperperfusion with the ASL technique using a dual postlabeling delay (PLD) of 1.5 and 2.5 s in nine patients, according to the presence or absence of the localized epileptogenic lesion (EL) on conventional 3 T-MRI, who were divided into Group EL+ (six patients) and Group EL- (three patients).

Results

Study-1 confirmed that the stratified representation of the periictal MRI findings depends on the time interval between the ictal cessation and MRI examination in addition to the magnitude and duration of the epileptic activity. In Study-2, two types of periictal hyperperfusion were noted. In all six Group EL+ patients, periictal ASL findings showed "fast flow type". Markedly increased ASL signals were noted at the epileptically activated cortex, having a tight topographical relationship with EL, on ASL with a PLD of 1.5 s, which is decreased on ASL with a PLD of 2.5 s. In all three Group EL- patients, periictal ASL findings showed "gradual flow type", which is characterized by gradual signal increase of the epileptically activated cortex on ASL with a PLD of 1.5 and 2.5 s.

Conclusion

We confirmed that ASL hyperperfusion is superior to DWI in the periictal detection of epileptic events. ASL with dual PLD offers the ability to document two types of hemodynamics of periictal hyperperfusion.

Abstract WP12: Mechanical Thrombectomy for Basilar Artery Occlusion

Background and Purpose: Basilar artery occlusion (BAO) is an infrequent cause of stroke, accounting for 1.1% of acute ischemic stroke cases. The natural history of patients with BAO is devastating, with morbidity rates of up to 80%. No previous randomized controlled studies on the efficacy of recanalization therapy have been reported.

Methods: In the present single-center study, consecutive BAO patients were treated with mechanical thrombectomy (MT) using the stent retriever and the Penumbra system. Computed tomography perfusion was used for patient evaluation. Clinical outcomes were correlated with demographic, clinical, and radiographic findings.

Results: Between October 2011 and March 2017, MT was performed in 37 patients with BAO (mean age 70.1±10.9). Mean baseline National Institutes of Health Stroke Scale was 23±11. Recanalization rate (≧thrombolysis in cerebral infarction 2b) was 100%. Mean onset to recanalization time (OTR) was 226.3±117.8minutes. Favorable outcome at 90 days (modified Rankin scale≦2) was 60.6%. Mortality rate at 90 days was 10.8%. In an univariate analysis, IV rt-PA use, and OTR were significantly associated with favorable outcomes. In a multivariate logistic regression model, IV rt-PA use and lower NIHSS score were significantly related to favorable outcomes.

Conclusions: Multimodal endovascular therapy using the Penumbra system and/or stent retriever demonstrated high recanalization rates and improved outcomes in BAO. Both devices were feasible and effective in the treatment of BAO. An approach combining MT with IV thrombolysis provided better recanalization rates and improved clinical outcomes.

Abstract WP355: Evaluation of a Checklist to Identify Early Signs of Hyperperfusion Syndrome After Carotid Endarterectomy

Background and purpose: Hyperperfusion syndrome (HPS) occurs in only 1-3% of patients after carotid endarterectomy (CEA). However, it can cause severe cerebral hemorrhage and may be lethal. Therefore, nurses need to be able to recognize the early signs of HPS and report them to the physician. In this study, we aimed to investigate the applicability of using the Intensive Care Delirium Screening Checklist (ICDSC) to discover early signs of postoperative HPS after CEA, allowing nurses to report the signs and possibly prevent disease progression.

Method: The study included 96 Japanese patients average age 71.9 ± 8.3 years old undergoing CEA from May 2008 to May 2017. There were 9 patients in the HPS group and 87 in the non-HPS group. Research design was a methodological study. To analyze differences between normally distributed continuous variables, the average value ± standard deviation was calculated and a t test used to compare between groups. For non-normally distributed continuous variables, the median and the range were calculated, and the Wilcoxon rank sum test was used to compare between groups. Ethical approval was granted by the Ethics Review Committee of the research execution facility.

Result: There was no significant difference in the patient characteristics in both groups. There was also no significant difference in the number of patients exhibiting signs of delirium (>4 points in total on the ICDSC) between the HPS group (n=8) and the non-HPS group (n=10). However, patients in the HPS group were unable to engage in conversation, while those in the non-HPS group responded to the nurses’ questions and several patients were able to engage in lucid conversation. The HPS group thus scored significantly higher than the non-HPS group on the "inappropriate speech or mood" ICDSC item (100% in the HPS group vs. 20% in the non-HPS group, P <0.001). In addition, on the "symptom fluctuation" item, the non-HPS group scored significantly higher than the HPS group (0% in the HPS group vs. 100% in the non-HPS group, P <0.001).

Conclusion: A total ICDSC score >4 and the presence of "inappropriate speech or mood" or "symptom fluctuation" strongly suggest the presence of HPS. In conclusion suggest that ICDSC is effective in identifying the early clinical signs of HPS after CEA.

[Five Cases of Neuroendovascular Treatment Using the Goose Neck Snare for Inducing and Holding the Guiding Catheter]

The stabilization of a guiding catheter is a very important factor for successful endovascular treatment. However, it is sometimes difficult to obtain sufficient stabilization because of the tortuosity of the approach route. A Goose Neck Snare is useful for the retrieval of intravascular foreign bodies and can be used to hold the guiding catheter. We describe five cases of endovascular treatment performed while using the Goose Neck Snare via the brachial artery to hold the guiding catheter. We discuss the utility of this strategy.

Mechanical Thrombectomy for Acute Basilar Artery Occlusion in Early Therapeutic Time Window

Background: The natural history of basilar artery occlusion (BAO) is devastating, with morbidity rates increasing up to 80%. However, the efficacy of recanalization therapy for BAO has not been established as yet. Objective: We analyzed consecutive cases of BAO treated with mechanical thrombectomy (MT) to evaluate its safety and efficacy and to determine factors associated with the prognosis. Methods: Between October 2011 and September 2016, MT was performed in 34 patients with BAO. MT was performed using the Penumbra system and stent retriever. CT perfusion was used for evaluating patients. Cerebral blood flow (CBF) maps and cerebral blood volume (CBV) maps were evaluated. CBF/CBV mismatch was defined as ≥50% penumbra. Clinical outcomes were correlated with demographic, clinical, and radiographic findings. Results: The median baseline National Institutes of Health Stroke Scale score was 29 (14-33). The recanalization rate (≥thrombolysis in cerebral infarction grades 2b) was 100%. The median onset to recanalization time (OTR) was 197 (160-256) min. Favorable outcomes (modified Rankin Scale ≤2) at 90 days occurred in 56% (n = 19 of 34). The mortality rate at 90 days was 12% (n = 4 of 34). In univariate analysis, intravenous (IV) recombinant tissue-type plasminogen activator (rt-PA) use, and OTR were significantly associated with favorable outcomes. In a multivariate logistic regression model, IV rt-PA use and lower National Institute of Health Stroke Scale score were significantly related to favorable outcomes. Conclusion and Relevance: Multimodal endovascular therapy using the Penumbra system and stent retriever demonstrated a high recanalization rate and favorable outcomes for BAO. Both devices were feasible and effective in the treatment of BAO. An approach combining MT with IV thrombolysis provided a better recanalization rate and more favorable clinical outcomes.

[Usefulness of Edoxaban for Deep Cerebral Venous Sinus Thrombosis with Hemorrhagic Infarction:A Case Report]

We describe a case of deep cerebral venous sinus thrombosis(DCVST)that was successfully treated by oral administration of the Xa inhibitor edoxaban. A 53-year-old man was admitted to our hospital because of a headache and undifferentiated dizziness. Computed tomography(CT)demonstrated a low-density area in the bilateral thalamus and high-density lesions in the internal cerebral veins(ICVs)and vein of Galen. Magnetic resonance imaging with diffusion-weighted images detected areas of hyperintensity in the bilateral thalamus. Additionally, the inferior sagittal sinus, ICV, and vein of Galen were not detected by CT venography or cerebral angiography. We therefore diagnosed DCVST and started anticoagulation therapy with heparin(IV)and warfarin. A week after admission, lesions that showed hypointensity on T2^* images and high density on CT scans were detected in the bilateral thalamus. We thought that hemorrhagic infarction had occurred in association with DCVST, and changed the anticoagulation therapy to oral administration of edoxaban on day 9. The patient's symptoms gradually diminished, and CT venography indicated partial recanalization of the DCV from the ICV to the vein of Galen on day 72. We report our experience, and discuss the safety and usefulness of the Xa inhibitor for treating DCVST with hemorrhagic infarction.

Optimal thresholds for ischemic penumbra predicted by computed tomography perfusion in patients with acute ischemic stroke treated with mechanical thrombectomy

Background and purpose

Optimal thresholds for ischemic penumbra detected by CT perfusion (CTP) in patients with acute ischemic stroke (AIS) have not been elucidated. In this study we investigated optimal thresholds for salvageable ischemic penumbra and the risk of hemorrhagic transformation (HT).

Methods

A total of 156 consecutive patients with AIS treated with mechanical thrombectomy (MT) at our hospital were enrolled. Absolute (a) and relative (r) CTP parameters including cerebral blood flow (aCBF and rCBF), cerebral blood volume (aCBV and rCBV), and mean transit time (aMTT and rMTT) were evaluated for their value in detecting ischemic penumbra in each of seven arbitrary regions of interest defined by the major supplying blood vessel. Optimal thresholds were calculated by performing receiver operating characteristic curve analysis in 47 patients who achieved Thrombolysis In Cerebral Infarction (TICI) grade 3 recanalization. The risk of HT after MT was evaluated in 101 patients who achieved TICI grade 2b–3 recanalization.

Results

Absolute CTP parameters for distinguishing ischemic penumbra from ischemic core were as follows: aCBF, 27.8 mL/100 g/min (area under the curve 0.82); aCBV, 2.1 mL/100 g (0.75); and aMTT, 7.30 s (0.70). Relative CTP parameters were as follows: rCBF, 0.62 (0.81); rCBV, 0.83 (0.87); and rMTT, 1.61 (0.73). CBF was significantly lower in areas of HT than in areas of infarction (aCBF, p<0.01; rCBF, p<0.001).

Conclusions

CTP may be able to predict treatable ischemic penumbra and the risk of HT after MT in patients with AIS.

Pure posterior communicating artery occlusion treated with mechanical thrombectomy

There has been no report of mechanical thrombectomy for a pure posterior communicating artery (PComA) occlusion. Here, we report the case of an 87-year-old woman with a disturbance of consciousness and left hemiparesis diagnosed with a right PComA occlusion. The patient was successfully treated using mechanical thrombectomy in combination with a stent retriever and the Penumbra system. A CT perfusion image showed cerebral blood flow reduction in the ipsilateral occipital lobe and thalamus. A CT angiography supported the diagnosis of an occlusion of fetal type PComA. The PComA could not be detected by internal carotidangiogram, but after deployment of stent retriever, the PComA was recanalised and distal embolus at the right posterior cerebral artery was visualised. The thrombus was then removed using the Penumbra system. Although the treatment for a PComA occlusion requires further investigation, the present case supports a thrombectomy as an effective rescue strategy for PComA occlusions.

[A Case of Middle Cerebral Artery Stenosis Presented with Limb-Shaking TIA]

Involuntary movement is a rare clinical manifestation of transient ischemic attack (TIA). However, limb-shaking TIA is well described presentation of carotid occlusive disease. We present the case of a patient who developed limb-shaking TIA associated with high-grade stenosis of middle cerebral artery (M1), which was treated with percutaneous transluminal angioplasty (PTA). The procedure was performed successfully without complication and the symptom disappeared immediately after the procedure. The patient remained free of symptoms at the 38-month follow-up. There was no tendency of restenosis of M1. In this case, PTA was technically feasible and beneficial for limb-shaking TIA with M1 stenosis. Limb-shaking TIA can be a symptom of high-grade stenosis of M1.

[A Girl with Intraorbital Varix: A Case Report]

We report a case of intraorbital varix. A 16-year-old girl showed sudden left-sided exophthalmos after vomiting. After several episodes of vomiting, she developed complete loss of vision in the left eye, followed by orbital pain, disruption of eye movement, and periorbital swelling. No change in symptoms or signs was observed after the Valsalva maneuver or jugular vein compression. Computed tomography (CT), magnetic resonance imaging (MRI), and angiography were inconclusive. Transcranial surgery revealed a large varix near the optic nerve. The lesion could not be completely resected because the orbital fat interfered with its complete visualization. We cauterized the lesion to reduce its volume. The patient's symptoms improved markedly after surgery and cauterization. Thus, cauterization appears to be an effective strategy to reduce the volume of an unresectable intraorbital varix.

Intracranial hemorrhage during dabigatran treatment

BACKGROUND

The incidence of intracranial bleeding during dabigatran treatment is lower than that during warfarin treatment. The characteristics of intracranial hemorrhage during dabigatran therapy, however, remain unclear.

METHODS AND RESULTS

The clinical data and treatment summaries of 9 intracranial bleeds that developed during dabigatran treatment in 8 patients with non-valvular atrial fibrillation were retrospectively reviewed. Five patients had small-moderate subdural hematomas, 2 had intracerebral hemorrhage and 1 had traumatic subarachnoid and parenchymal hemorrhage associated with cerebral contusion. Activated partial thromboplastin time upon admission ranged from 31.6 to 72.4s. After admission, systolic blood pressure in the 2 patients with intracerebral hemorrhage was maintained below 140 mmHg, and the subdural hematomas in 4 patients were surgically treated. None of the hematomas became enlarged and outcome was good in most cases.

CONCLUSIONS

Hematomas that arise due to acute intracranial bleeding during dabigatran treatment seem to remain small to moderate, hard to expand, and manageable.

Combined argatroban and anti-oxidative agents prevents increased vascular contractility to thrombin and other ligands after subarachnoid haemorrhage

BACKGROUND AND PURPOSE

Increased vascular contractility plays a fundamental role in cerebral vasospasm in subarachnoid haemorrhage (SAH). We investigated the role of thrombin and its receptor, proteinase-activated receptor 1 (PAR1), and other G protein-coupled receptors in the increased contractility, and examined the preventive effects of the thrombin inhibitor, argatroban, and anti-oxidative agents, vitamin C and tempol.

EXPERIMENTAL APPROACH

A rabbit model of SAH was utilized. Contractile responses of the isolated basilar artery and the level of oxidative stress of brain tissues were evaluated.

KEY RESULTS

Contractile responses to thrombin and PAR1-activating peptide (PAR1-AP) were enhanced and prolonged after SAH. The thrombin-induced contraction persisted even after terminating thrombin stimulation. When sequentially stimulated with PAR1-AP, the second response was maintained in SAH, while it was substantially attenuated in the control. Only a combination of argatroban with vitamin C or tempol prevented both the enhancement and prolongation of the contractile response to PAR1-AP and restored the reversibility of the thrombin-induced contraction. The responses to angiotensin II, vasopressin and PGF(2α) were enhanced and prolonged after SAH to varying degrees, and responded differently to the treatment. The response to vasopressin exhibited a similar phenomenon to that seen with PAR1-AP. Oxidative stress was increased in SAH, and normalized by the treatment with argatroban, vitamin C or their combination.

CONCLUSIONS AND IMPLICATIONS

Increased vascular reactivity to agonists in SAH was attributable to the enhancement and prolongation of the contractile response. A combination of argatroban and anti-oxidative agents was required to prevent both the enhancement and prolongation of the contractile response.

Mechanisms underlying potentiation of endothelin-1-induced myofilament Ca(2+) sensitization after subarachnoid hemorrhage

Increased vascular smooth muscle contractility has an important role in the development of cerebral vasospasm after subarachnoid hemorrhage (SAH). Myofilament Ca(2+) sensitivity is a major determinant of smooth muscle contractility. We investigated changes in the Ca(2+)-sensitizing effect of endothelin-1 (ET-1) and the mechanisms underlying ET-1-induced Ca(2+) sensitization after SAH using a rabbit SAH model. After SAH, the contractile response to ET-1 was enhanced, and the ET(A) receptor expression was upregulated in the basilar artery. In α-toxin-permeabilized preparations, ET-1 induced enhanced and prolonged contraction after SAH, suggesting that ET-1-induced Ca(2+) sensitization is potentiated after SAH. Endothelin-1-induced Ca(2+) sensitization became less sensitive to inhibitors of Rho-associated coiled-coil protein kinase (ROCK) and protein kinase C (PKC) after SAH. The expression of PKCα, ROCK2, PKC-potentiated phosphatase inhibitor of 17 kDa (CPI-17) and myosin phosphatase target subunit 1 (MYPT1) was upregulated, and the level of phosphorylation of CPI-17 and MYPT1 was elevated after SAH. This study demonstrated for the first time that the Ca(2+)-sensitizing effect of ET-1 on myofilaments is potentiated after SAH. The increased expression and activity of PKCα, ROCK2, CPI-17, and MYPT1, as well as the upregulation of ET(A) receptor expression are suggested to underlie the enhanced and prolonged Ca(2+) sensitization induced by ET-1.

Intracranial dural arteriovenous fistula with retrograde cortical venous drainage: use of susceptibility-weighted imaging in combination with dynamic susceptibility contrast imaging

BACKGROUND AND PURPOSE

SWI is a new MR imaging method that maximizes sensitivity to magnetic susceptibility effects with phase information for visualizing small cerebral veins. The purpose of this study was to report the use of SWI in combination with DSC in examining related RCVD in patients with intracranial DAVFs.

MATERIALS AND METHODS

Ten patients with angiographically confirmed DAVFs with RCVD underwent conventional MR imaging, SWI, and DSC. The ability of SWI to depict dilated cerebral veins was evaluated and then compared with DSC. The hemispheres of patients with DAVFs were grouped into affected (with RCVD) or nonaffected (without RCVD) categories by angiography. Four patients had bilaterally affected hemispheres. A total of 14 affected hemispheres in patients with DAVFs with RCVD were evaluated.

RESULTS

SWI showed dilated cerebral veins on the surface of the brain in all (100%) of the 14 affected hemispheres in patients with DAVFs with RCVD and deep in the brain in 9 (64%). T2-weighted imaging showed prominent flow-voids on the surface of the brain in 10 (71%) of the 14 affected hemispheres in patients with DAVFs with RCVD and deep in the brain in 5 (36%). DSC showed increased cerebral blood volume in all of the 14 affected hemispheres. The SWI findings regarding dilated veins on the surface of the brain corresponded well with the areas of increased cerebral blood volume.

CONCLUSIONS

SWI in combination with DSC could be used to characterize the presence of RCVD in patients with DAVFs.

Impaired feedback regulation of the receptor activity and the myofilament Ca2+ sensitivity contributes to increased vascular reactiveness after subarachnoid hemorrhage

Cerebral vasospasm determines the prognosis of subarachnoid hemorrhage (SAH). The increased vascular reactiveness has an important role in the development of cerebral vasospasm. This study analyzed the roles of the receptor-mediated signaling and the myofilament Ca(2+) sensitivity in the increased vascular reactiveness in SAH, using the basilar artery of a rabbit SAH model. Endothelin-1, thrombin, and phenylephrine induced transient increases in [Ca(2+)](i), myosin light chain phosphorylation, and contraction in the controls. All these responses were not only enhanced but also became sustained in SAH. In the sequential stimulation of thrombin receptor or alpha(1)-adrenoceptor, the second response was substantially attenuated in the controls, whereas it was maintained in SAH. The thrombin-induced contraction in SAH irreversibly persisted even after terminating the thrombin stimulation. This contraction was completely reversed by trypsin and a Galpha(q) inhibitor YM254890, thus suggesting the sustained receptor activity during the sustained contraction. YM254890 also inhibited the endothelin-1- and phenylephrine-induced sustained contraction. Furthermore, the GTPgammaS-induced transient contraction in the control alpha-toxin-permeabilized strips was converted to a sustained contraction in SAH. The results provide the first evidence that the feedback inactivation of the receptor activity and the myofilament Ca(2+) sensitivity was impaired in SAH, thus contributing to the increased vascular reactiveness.

Effect of tumor removal on tinnitus in patients with vestibular schwannoma

OBJECT

Tinnitus is one of the most common symptoms in patients with vestibular schwannomas (VSs), but the effect of surgery on this symptom has not been fully evaluated. The aim of this study was to define the effect on tinnitus of tumor removal, cochlear nerve resection, and useful hearing preservation in patients with VSs.

METHODS

The authors retrospectively analyzed the status of tinnitus before and after surgery in 242 patients with unilateral VSs who underwent surgery via the retrosigmoid lateral suboccipital approach.

RESULTS

Of 242 patients, 171 (70.7%) complained of tinnitus before surgery; the symptom disappeared in 25.2%, improved in 33.3%, remained unchanged in 31.6%, and worsened in 9.9% of these cases after tumor removal. In the 171 patients with preoperative tinnitus, the cochlear nerve was resected in 85 (49.7%) and preserved in 86 (50.3%), but there was no significant difference in the incidence of postoperative tinnitus between these 2 groups (p = 0.293). In the 71 patients without preoperative tinnitus, the symptom developed postoperatively in 6 cases (8.5%). Among those without preoperative tinnitus, the cochlear nerve was resected in 45 cases (63.4%) and tinnitus appeared postoperatively in 3 (6.7%). The authors also analyzed the association between postoperative tinnitus and useful hearing preservation, but could not find any statistically significant association between the 2 factors (p = 0.153).

CONCLUSIONS

Tumor removal via the retrosigmoid lateral suboccipital approach may provide some chance for improvement of tinnitus in patients with VSs; however, neither cochlear nerve resection nor useful hearing preservation affects the postoperative development of tinnitus.

Enhanced contractile response of the basilar artery to platelet-derived growth factor in subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The level of platelet-derived growth factor (PDGF) in cerebrospinal fluid is elevated in subarachnoid hemorrhage (SAH). Therefore, the contractile effect of PDGF on the basilar artery was examined in SAH.

METHODS

A rabbit double-hemorrhage SAH model was used. In the medial layers of the control basilar artery, PDGF had no effect on contraction up to 1 nmol/L, whereas 3 nmol/L PDGF induced slight contraction. In SAH, PDGF induced an enhanced contraction with an increase in [Ca(2+)](i) at 1 nmol/L and higher concentrations. The levels of [Ca(2+)](i) and tension induced by 1 nmol/L PDGF in SAH were 17% and 20%, respectively, of those obtained with 118 mmol/L K(+) depolarization. The PDGF-induced elevation of [Ca(2+)](i) and contraction seen in SAH were abolished in the absence of extracellular Ca(2+). In alpha-toxin-permeabilized strips of SAH animals, PDGF induced no further development of tension during contraction induced by 300 nmol/L Ca(2+), suggesting no direct effect on myofilament Ca(2+) sensitivity. Genistein at 10 micromol/L completely inhibited the tension induced by 1 nmol/L PDGF. The level of myosin light-chain phosphorylation was significantly increased by 1 nmol/L PDGF.

CONCLUSIONS

These results show that the contractile response to PDGF of the basilar artery was enhanced in SAH. The PDGF-induced contraction depended mostly on tyrosine phosphorylation and Ca(2+)-dependent myosin light-chain phosphorylation. The enhancement of the responsiveness to PDGF may therefore contribute to the development of cerebral vasospasm after SAH.

Hematopoietic stem cells prevent hair cell death after transient cochlear ischemia through paracrine effects

Transplantation of hematopoietic stem cells (HSCs) is regarded to be a potential approach for promoting repair of damaged organs. Here, we investigated the influence of hematopoietic stem cells on progressive hair cell degeneration after transient cochlear ischemia in gerbils. Transient cochlear ischemia was produced by extracranial occlusion of the bilateral vertebral arteries just before their entry into the transverse foramen of the cervical vertebra. Intrascalar injection of HSCs prevented ischemia-induced hair cell degeneration and ameliorated hearing impairment. We also showed that the protein level of glial cell line-derived neurotrophic factor (GDNF) in the organ of Corti was upregulated after cochlear ischemia and that treatment with HSCs augmented this ischemia-induced upregulation of GDNF. A tracking study revealed that HSCs injected into the cochlea were retained in the perilymphatic space of the cochlea, although they neither transdifferentiated into cochlear cell types nor fused with the injured hair cells after ischemia, suggesting that HSCs had therapeutic potential possibly through paracrine effects. Thus, we propose HSCs as a potential new therapeutic strategy for hearing loss.

Intracranial dural arteriovenous fistulas with retrograde cortical venous drainage: assessment with cerebral blood volume by dynamic susceptibility contrast magnetic resonance imaging

BACKGROUND AND PURPOSE

Retrograde cortical venous drainage (RCVD) is the most major risk factor for aggressive behavior of intracranial dural arteriovenous fistulas (DAVF). The purpose of this study was to assess the efficacy of relative cerebral blood volume (rCBV) map for RCVD in patients with DAVF.

METHODS

Ten patients with angiographically proven DAVF with RCVD, 2 reference patients with DAVF without RCVD, and 10 control subjects underwent examinations with dynamic susceptibility contrast (DSC)-MR imaging. Four patients with DAVF with unilateral RCVD were evaluated, before and after treatment. The calculation of mean rCBV ratio was performed on a hemispheric basis. The mean rCBV ratio was defined as the value on one side (higher value side) divided by that on the other side (lower value side).

RESULTS

In all patients with DAVF with RCVD, the rCBV map showed an increase in rCBV of the angiographically proved affected hemisphere. In 2 reference patients with DAVF without RCVD and all control subjects, the rCBV map showed no increase of rCBV. The mean rCBV ratio in patients with DAVF with RCVD was significantly higher than that of control subjects (P = .0002). Treatment response for RCVD was indicated by a decrease of CBV on the rCBV map and by a decrease of 22% in the mean rCBV ratio.

CONCLUSIONS

Increased rCBV by DSC-MR correlated with RCVD in patients with DVAF. The assessment with rCBV for RCVD may be more quantitative than that with angiogram.

Effects of acute citalopram treatment on the methamphetamine-induced locomotor activity

1. Previously the authors have shown that acute citalopram treatment increased the dopamine D2 receptor expression in rat brain striatum (Kameda et al., 2000). In the present study, the authors attempted to determine whether these effects of citalopram influence the methamphetamine-induced locomotor activity. 2. The pretreatment with a single administration of citalopram (10 mg/kg, i.p.) resulted in the significant enhancement of the locomoter activity induced by methamphetamine treatment (1 mg/kg, i.p.). The enhancement was observed 30 min, 12 hours, 24 hours, but not 7 days after withdrawal of citalopram administration. 3. Then the authors determined the methamphetamine concentration in rat brain striatum by gas chromatography-mass spectrometry (GC-MS) The results showed that the concentration of methamphetamine wars significantly higher in the rats 24 hours, and also 7 days after withdrawal of citalopram administration, compared to the control rats. 4. These results emphasized the involvement of the high methamphetamine concentration, caused by the pretreatment with citalopram, in the enhancement of the methamphetamine-induced locomotor activity. However high methamphetamine concentration alone could not account for this enhancement, since the high concentration of methamphetamine observed 7 days after withdrawal of citalopram administration did not appear to enhance the methamphetamine-induced locomotor activity. Another mechanism through which the pretreatment with citalopram enhanced the methamphetamine-induced locomotor activity, such as the increased expression of the dopamine D2 receptors, could not be excluded.

Effects of lithium on dopamine D2 receptor expression in the rat brain striatum

Effects of lithium on the dopamine D2 receptor expression in the rat brain striatum were studied. Feeding the chow containing 0.2% LiCO3 for 6 days increased the level of the dopamine D2 receptor mRNA, and the transcription rate of the dopamine D2 receptor gene, indicating the stimulatory effects of lithium on the transcription of the dopamine D2 receptor gene. [3H] Spiperone binding to the striatal membranes increased in the rats treated with lithium, while the Western blotting analysis showed no change of the amount of the dopamine D2 receptors. These results suggested that lithium might induce the conformational changes of the dopamine D2 receptors. The methamphetamine-induced locomotor activity was enhanced by the pretreatment with lithium, whereas simultaneous increase in the methamphetamine concentration in the striatum was also observed. These observations suggested that the stimulation of methamphetamine-induced locomotor activity by lithium might be, at least partly, due to either increased sensitivity of the dopamine receptors, or increased concentration of methamphetamine in brain, or combination of both.

[A case of breast cancer with bone marrow and liver metastases responding completely to low-dose weekly paclitaxel combined with toremifene]

A 36-year-old woman was admitted to our hospital because of general malaise in October 1999. She was diagnosed with bilateral breast cancer with bone marrow and liver metastases. Low-dose weekly paclitaxel (60 mg/body/week) combined with toremifene (120 mg/day) was started in December 1999. Myelofunction was recovered after 2 weeks of chemotherapy (CT), and the primary tumors and cervical/axillary lymphadenopathy disappeared after 4 weeks of CT. Bone marrow and liver metastases was no longer detected after 16 weeks of CT, and the case was evaluated as a complete response (CR). The same therapy has been performed for eight months and no evidence of recurrence has been observed.

The role of intracellular Ca(2+) in apoptosis induced by hyperthermia and its enhancement by verapamil in U937 cells

PURPOSE

The relationship between apoptosis induced by 42 degrees C and 44 degrees C hyperthermia alone or in combination with verapamil and changes in intracellular Ca(2+) concentration ([Ca(2+)]i) was investigated in U937 cells.

METHODS

Apoptosis induced by hyperthermia was assessed according to DNA fragmentation, nuclear morphologic changes, and expression of phosphatidylserine on the outside plasma cell membrane. These changes were measured by flow cytometry. The [Ca(2+)]i of individual cells after hyperthermia was monitored by a digital image-analyzing technique using Fura-2.

RESULTS

Hyperthermia-induced apoptosis reached a plateau after 6 h and was found to be both time and temperature-dependent. DNA fragmentation was maximum at 44 degrees C after 30 min. Verapamil enhanced the apoptosis induced by 42 degrees C and 44 degrees C hyperthermia in normal cells and by 44 degrees C hyperthermia in thermotolerant cells. The number of cells containing higher [Ca(2+)]i (more than 200 nM) was significantly increased by hyperthermia and further elevated by the addition of verapamil in both normal and thermotolerant cells. Apoptosis induced by hyperthermia was markedly decreased by an intracellular Ca(2+) chelator, BAPTA-AM, in a dose-dependent manner.

CONCLUSION

These results indicate that [Ca(2+)]i increase plays a crucial role in apoptosis induced by hyperthermia and the combined treatment with verapamil in normal and thermotolerant U937 cells. Furthermore, hyperthermia-combined drug therapy has potential significance in cancer therapy.

Relationships between lipolysis induced by various lipolytic agents and hormone-sensitive lipase in rat fat cells

Norepinephrine induced lipolysis in rat fat cells, in vitro, in a time- and concentration-dependent manner, without concomitantly increasing hormone-sensitive lipase (HSL) activity. It also induced, time and concentration dependently, HSL translocation from the cytosol to the lipid droplets in fat cells. Isoproterenol, forskolin, dibutyryl cyclic AMP, and theophylline also induced lipolysis in fat cells, but did not stimulate HSL activity. These agents also induced HSL translocation from the cytosol to the lipid droplets in fat cells: about 80% to 90% of all HSL was located in lipid droplets after incubation for 1 h. These results suggest that the critical event in lipolytic activation of fat cells induced by lipolytic agents is not an increase in the catalytic activity of HSL but translocation of HSL to its substrate on the surfaces of lipid droplets in fat cells.-Morimoto, C., K. Kameda, T. Tsujita, and H. Okuda. Relationships between lipolysis induced by various lipolytic agents and hormone-sensitive lipase in rat fat cells. J. Lipid Res. 2001. 42: 120;-127.

Treatment response in depressed patients with enhanced Ca mobilization stimulated by serotonin

Serotonin (5-HT)-stimulated intraplatelet calcium (Ca) mobilization has been shown to be enhanced in nonmedicated depressive patients by many studies. However, there has not been any longitudinal follow-up study of this parameter. We examined the relationship between treatment response and pretreatment value of the 5-HT-induced Ca response. The 5-HT(10 microM)-induced intraplatelet Ca mobilization was measured in 98 nonmedicated depressive patients (24 bipolar disorders, 51 melancholic major depressive disorders, and 23 non-melancholic major depressive disorders). These patients were followed up prospectively for a further period of five years. The depressed patients with enhanced Ca response to 5-HT in bipolar disorders exhibited a good response to mood stabilizers but those with major depressive disorders showed a poor response to antidepressants. These findings suggest the possibility that the 5-HT-induced intraplatelet Ca response may be a good predictor of treatment response in depressed patients. Longer longitudinal follow-up studies are needed in larger samples to examine if this parameter may be a specific biological marker for unipolar-bipolar dichotomy.

[Thinking about tuberculosis in Osaka City]

The incidence rate of tuberculosis in Osaka City (104.2 per 100,000 population) is extremely high, namely 3 times higher than the national average. Why the tuberculosis situation of Osaka City is so bad? The reason could be summarized as follows: Before the end of the World War II (1945), it was the sequelae of high prevalence observed in the era of Meiji, Taisho and early years of Showa. However, after the World War II, especially from the Heisei era (1989-), it is deeply affected by the influence of socio-economic background in Japan. Osaka City is characterized as the city of merchants and small enterprises. And therefore, the city substantially has the nature of the locality that brings in or produces some kinds of social vulnerability such as temporary laborers and homeless people. Of the tuberculosis patients in Osaka City, about 20% are homeless. In addition, patients of the smear positive infectious tuberculosis are often discovered among temporary laborers who change their residences and job sites from place to place and contact widely with citizens. These two are the most difficult problems in tuberculosis control program of Osaka City. In the meantime, there are many citizens who are careless of their health and do not follow the law or social rule, and this has apparently no direct connection with the problems of tuberculosis. However, it might be one of the factors of an undesirable trend of tuberculosis in Osaka City. In order to improve such a unfavorable tuberculosis situation in Osaka City, effective and strong supporting activities to the tuberculosis program are essentially needed. And these activities must be done from the standpoint of health-promotion, namely, health education for citizens and improvement of social environmental conditions to maintain healthy and cultural life.