De novo arteriovenous malformation in a patient with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant systemic disorder characterized by the enlargement of capillaries, recurrent nosebleeds, and multiple arteriovenous malformations (AVMs). Although cerebral AVMs are traditionally considered to be congenital lesions, some reports have described de novo AVMs, which suggests that the authors believed them to be dynamic conditions. In this article, the authors describe the case of a 5-year-old boy with HHT in whom a de novo cerebral AVM was detected after a negative MRI result at 5 months. To the authors' knowledge, this is the first report of a de novo AVM in a patient with HHT. In patients with a family history of HHT, de novo AVMs are possible, even when no lesions are detected at the first screening. Therefore, regular screenings need to be performed, and the family should be informed that AVMs could still develop despite normal MRI results.

Abstract 9: A Novel Large Cerebral Aneurysm Model in Rats with Intraperitoneal Administration of Beta-AminoPropioNitril-Fumarate

Introduction: Mechanisms of formation, enlargement, and rupture of cerebral aneurysm (CA) are not fully understood. Unveiling the mechanisms lead to the prevention of a life-threatening subarachnoid hemorrhage. Although several CA models in rats have been reported, most of CAs in the models are immature and insufficient for the close investigation into the mechanisms of enlargement and rupture. The establishment of a large CA model is required for full disclosure of the mechanisms.

Methods: A new CA model in rats was designed by modifying the Hashimoto model in that high-dose β-aminopropionitril fumarate (BAPN-F) was administrated intraperitoneally. Seven-week-old male Sprague-Dawley rats were deeply anesthetized, the left common carotid artery was dissected and the bilateral posterior branches of the renal artery were ligated. After the operation, rats were fed food with 8% sodium chloride and divided into 4 groups according to the weekly dose amount of BAPN-F as well as the breeding periods (group 1: n=31, 400mg/kg for 4weeks, group 2: n=31, 400mg/kg for 8weeks, group 3: n=27, 2800mg/kg for 8weeks, group 4: n=13, 2800mg/kg for 12weeks). We then investigated aneurysmal development pathologically along with calculating CA induction rate and mortality rate in each group.

Results: Continuous hypertension were induced in all groups. CA induction rate was 19.4%, 29%, 85.2%, and 84.6% while mortality was 12.9%, 16.1%, 7.4% and 30.1% in the group 1, 2, 3, and 4, respectively. Group 3 has statistically significant differences in both the induction rate (p=0.018) and mortality (p=0.027). Among 4 groups, CAs were located at anterior cerebral artery - ophthalmic artery bifurcation, anterior communicating artery (Acom A), and posterior communication artery (Pcom A). We defined the large CA as over one and a half times the size of its parent artery. Large CAs were predominantly detected at Acom A and Pcom A in the group 3 (22.2%) and 4 (23.1%). In addition, all large CAs were morphologically and histologically similar to that of human.

Conclusions: Intraperitoneal administration of 2800mg/kg BAPN-F enabled us to induce large CAs with 20% induction rate and low mortality. A further investigation of this model should be promising for full disclosure of the CAs mechanisms.

Abstract WP110: The Next Generation of Autologous Bone Marrow Stromal Cell Transplantation Against Stroke

Background and purpose: Recent studies have elucidated that the bone marrow stromal cells (BMSCs) have therapeutic potential against stroke. Some clinical trials have been starting up in practice. We aimed to evolve the autologous BMSC transplantation for stroke into the next generation.

Materials and methods: Human BMSCs were cultured with human platelet lysate (hPL) instead of fetal calf serum (FCS). They were labeled with superparamagnetic iron oxide (SPIO). Rat ischemic stroke models were made and 5x105 cells were injected into the ipsilateral striatum stereotactically 7 days post-insult. Behavioral analysis, MRI for cell tracking, (18)F-FDG PET, and (123)I-Iomazenil SPECT were performed. The animals were sacrificed 5 to 8 weeks post-transplantation and histological analysis was performed.

Results: There was no difference in the surface markers and cell proliferation between hPL and FCS. Although rotarod test showed that motor function deteriorated in rats suffered from permanent MCAo, BMSC-hPL transplantation enhanced recovery of the motor function, significantly. MRI demonstrated that SPIO-BMSCs aggressively migrated towards the lesion. Moreover, (18)F-FDG PET and (123)I-Iomazenil SPECT showed that BMSC transplantation promoted recovery of the glucose utilization and the binding potential of iomazenil in the peri-infarct area, respectively. Histological analysis supported the findings on MRI and showed the inclination for neural differentiation of donor cells.

Conclusion: The hPL may be valuable and safe in expanding BMSCs. The application of bio-imaging techniques is also valuable for BMSC transplantation for stroke. Now we prepare the novel clinical trial against stroke, Research on Advanced Intervention using Novel Bone marrOW stem cell (RAINBOW) study. The present results are translated into the optimal design of the trial.

Abstract TP234: New Clinical Application of Measurement of Blood Viscosity With an Electromagnetically Spinning Sphere Viscometer in Acute Ischemic Stroke Patients

Introduction: Blood viscosity (BV) is an important blood property for determining the hemodynamic status. High BV causes blood stagnation and subsequent thrombotic reactions leading to cerebral infarction. However, clinical application of the measurement of BV is out of fashion due to the stereotype that the measurement results are within expectations with less clinical value.

Hypothesis: Since the importance of BV remains unchanged in the pathogenesis of vascular diseases, BV values should still contain important information. We hypothesize that BV values may differ among stroke subtypes based on pathological condition.

Methods: A new type of viscometer was recently developed using an electromagnetically spinning sphere (EMS) method, which enable us to measure small amount of samples quickly and sequentially in non-contact disposable manner. We measured BV in 100 healthy outpatients and 67 acute ischemic stroke patients (atherothrombotic: 28, lacunar: 23, and cardioembolic: 16) with EMS viscometer. The relationships between BV and hematological parameters were analyzed. The measurements in the acute stroke patients were performed a total of 4 times (Day0, Day2, Day7, and Day14 from the admission).

Results: BV values in the healthy outpatients correlated more strongly with the total count of red blood cells and platelets (R2=0.6957) than with the hematocrit (R2=0.6435) in an exponential approximation. Compared with BV values in the healthy outpatients (4.57±0.76 mPa·s), Day0 BV values in the lacunar patients (5.37±1.11 mPa·s) were significantly higher (p<0.01), but those in the atherothrombotic patients (4.82±0.98 mPa·s) and in the cardioembolic patients (4.66±0.93 mPa·s) were not significantly different. In comparison between the values at Day 0 and Day 14, the lacunar patients alone showed a significant decrease from Day0 to Day14, suggesting that the lacunar patients suffered from dehydration at the onset.

Conclusion: BV values at Day0 of lacunar infarction were significantly increased, which indicated contribution of dehydration to the onset of lacunar infarction. These measurements were performed with only 0.3ml of blood quickly and sequentially; therefore, the clinical application of the EMS viscometer appears to be promising.

Abstract WP112: Trans-arterial Regional Hypothermia Provides Robust Neuroprotection in Rat Permanent Middle Cerebral Artery Occlusion Model

Background and Purpose: We previously reported the neuroprotective effects of trans-arterial regional hypothermia in rat transient middle cerebral artery occlusion (tMCAO) model (ISC 2014, ISC 2015). The tMCAO model is representative of the clinical setting of successful recanalization in acute ischemic stroke. However, it is not always possible to achieve successful recanalization. Herein, we investigated the neuroprotective effects of trans-arterial regional hypothermia in permanent MCAO (pMCAO) model as well.

Methods: Three groups were provided to investigate the neuroprotective effects. Regional hypothermia group had a single infusion of 20ml/kg 10°C cold saline via the ipsilateral internal carotid artery for 15 min at 0 hr or 1 hr after the onset of pMCAO. Vehicle group had a 37°C warm saline infusion in the same manner. Control group had no infusion after pMCAO. The rats were tested for neurological score after 48-hour pMCAO and then sacrificed to evaluate infarction size and pathological condition. Immunohistochemical analysis was performed to investigate the neuronal apoptosis (NeuN, cleaved caspase 3), glial reaction (GFAP), and microglial activation (Iba-1).

Results: The regional hypothermia group showed significantly better neurological score compared with the other groups (p<0.01). Infarct volume was significantly smaller in the regional hypothermia group (8.1±4.7% at 0 hr and 15.7±5.9% at 1 hr) than in the vehicle group (35.8±5.6% at 0 hr and 34.0±3.6% at 1 hr) and also in the control group (35.1±8.9%) (p<0.01). Neuronal apoptosis (p<0.01), reactive gliosis (p<0.01), and microglial activation (p<0.05) in the peri-infarct area were significantly inhibited in the regional hypothermia group compared with the other groups. The degree of the inhibition was somewhat more evident at 0 hr than at 1 hr.

Conclusions: Our result demonstrated that trans-arterial regional hypothermia provided robust neuroprotection in pMCAO model as well as tMCAO model, suggesting that this therapy may have a wide clinical application in ischemic stroke treatment.

Abstract WP61: A Novel Application of Four-dimensional Magnetic Resonance Angiography Using Arterial Spin Labeling for Assessment of Postoperative Cerebral Hemodynamic Changes in Moyamoya Disease

Introduction: Recently, four-dimensional magnetic resonance angiography without contrast enhancement using arterial spin labeling (ASL-4D MRA) has become available to visualize the intracranial arteries. However, few reports are available about the efficacy of ASL-4D MRA in moyamoya disease (MMD).

Hypothesis: We hypothesized that postoperative hemodynamic changes in MMD patients could be evaluated using ASL-4D MRA.

Methods: This study included 26 hemispheres of 21 patients who underwent combined direct and indirect revascularization for MMD. ASL-4D MRA was serially performed before and after surgery. We assessed the time phases where signals of the arteries were detected on ASL-4D MRA in order to analyze perioperative changes in cerebral hemodynamics.

Results: The signals of the anastomosed arteries on ASL-4D MRA were detected and disappeared at significantly earlier time phase after surgery than before. This change in acute period was moderated in chronic period after surgery. Postoperative hyperperfusion was observed in 12 of 26 hemispheres within 7 days after surgery. The signals of the arteries were detected significantly earlier in hemispheres with hyperperfusion than those without. In cases with hyperperfusion, ASL-4D MRA demonstrated high intensity of peripheral middle cerebral artery (MCA) around anastomosed region in early time phase (Figure). This “early hyperintensity of MCA” was observed in all cases with hyperperfusion and corresponded to the timing of the occurrence of hyperperfusion. Furthermore, this hyperperfusion-specific sign could not be detected by routine TOF MRA.

Conclusions: Noninvasive ASL-4D MRA successfully evaluated perioperative dynamic changes of cerebral blood flow and the effect of surgical revascularization in MMD. This next generation modality could also visualize cerebral hemodynamics in cases with postoperative hyperperfusion and would be quite useful for appropriate postoperative management.

[Efficacy of Stent-Assisted Coil Embolization for a Dissecting Aneurysm of the Cervical Internal Carotid Artery Caused by a Systemic Vascular Disease: A Case Report]

Systemic vascular diseases such as fibromuscular dysplasia, Ehlers-Danlos syndrome, Marfan syndrome, and Behçet's disease are known to cause spontaneous dissecting aneurysms of the cervical internal carotid artery. These diseases are generally associated with vascular fragility; therefore, invasive treatments are avoided in many cases of dissecting aneurysms, and a conservative approach is used for the primary disease. Surgical or intravascular treatment may be chosen when aneurysms are progressive or are associated with a high risk of hemorrhage; however, there is no consensus on which treatment is better. We report a case of a dissecting aneurysm of the cervical internal carotid artery in a patient with suspected Behçet's disease, which was treated using stent-assisted coil embolization. A man in his 40's, with suspected Behçet's disease, presented with an enlarged dissecting aneurysm of the right cervical internal carotid artery. The lesion was present for approximately 10 years. We performed stent-assisted coil embolization for the lesion. Post-surgery, no aneurysms were detected with carotid artery echography. Our case report suggests that stent-assisted coil embolization is a promising treatment for dissecting aneurysms of the cervical internal carotid artery. In addition, the procedure demonstrates the utility of carotid artery echograms for examining recanalization after stent-assisted coil embolization.

Lateral Position of the External Carotid Artery: A Rare Variation to Be Recognized During Carotid Endarterectomy

BACKGROUND

External carotid artery (ECA) positioned laterally to the internal carotid artery (ICA) at the level of the common carotid artery (CCA) bifurcation is occasionally encountered during carotid endarterectomy (CEA). This study aimed to determine the frequency of this phenomenon and provide technical tips for performing CEA.

METHODS

The study included 199 consecutive patients (209 carotid arteries) who underwent CEA at Otaru Municipal Medical Center in 2007-2014. The position of the ECA with respect to the ICA at the CCA bifurcation was preoperatively rated as either lateral or normal, using three-dimensional computerized tomographic angiography (3-D CTA) anteroposterior projections. Postoperative diffusion-weighted images (DWIs), and postoperative 3-D CTA images were reviewed.

RESULTS

Among the 209 carotid arteries with atherosclerosis, 11 instances (5.3 %) of lateral position of the ECA were detected in 11 patients. Ten of these arteries (91 %) were right-sided (odds ratio 11.1; 95 % confidence interval 1.38-88.9). Wider longitudinal exposure of the arteries was used during CEA, and the CCA and ECA were rotated clockwise or counter clockwise. The ICA lying behind the ECA along the surgical access route was then pulled out laterally and moved to the shallow surgical field. Cross-clamping, arteriotomy, plaque removal, and wall suturing were performed as usual. No cerebral infarcts were detected on postoperative DWIs, and 3-D CTA revealed no CCA and ICA kinking.

CONCLUSIONS

Lateral position of the ECA is not extremely rare in patients undergoing CEA for atherosclerosis and may be a congenital variation, although this is still controversial. CEA can be performed safely if the arteries from the CCA to the ICA are rotated, and the ICA is moved to the shallow surgical field under wider longitudinal exposure. Although no postoperative cerebral infarcts were detected, the risk of artery-to-artery embolism resulting from artery repositioning prior to plaque removal should be taken into consideration.

Postoperative Acute Submandibular Sialadenitis after Neurosurgery: Two Case Reports and a Review of the Literature

This article details two case reports and reviews the extant literature concerning acute postoperative submandibular sialadenitis occurring in the side contralateral to the operated site after neurosurgery. Although its precise pathogenesis remains to be elucidated, it is likely related to intraoperative compression of the submandibular gland and surrounding tissues, caused by head positioning and the endotracheal tube. Submandibular swelling rapidly deteriorates after surgery, and emergent airway protection is required in most cases in order to avoid fatal airway obstruction. To avoid serious sequelae, we should be aware of acute submandibular sialadenitis that occurs contralateral to the surgical side, which, although rare, is more probable after posterior fossa surgery. When it occurs, early airway protection is crucial, and the following conservative treatment could provide a good prognosis.

A novel application of four-dimensional magnetic resonance angiography using an arterial spin labeling technique for noninvasive diagnosis of Moyamoya disease

BACKGROUND

Noncontrast-enhanced time-resolved four-dimensional magnetic resonance angiography using an arterial spin labeling technique (ASL-4D MRA) is emerging as a next generation angiography for the management of neurovascular diseases. This study evaluated the feasibility of ASL-4D MRA for the diagnosis of Moyamoya disease (MMD) and MMD staging by using digital subtraction angiography (DSA) and time-of-flight MRA (TOF MRA) as current standards.

METHODS

Eleven consecutive non-operated patients who underwent DSA for the diagnosis of MMD were recruited. Two independent observers evaluated the three tests. The data were analyzed for inter-observer and inter-modality agreements on MMD stage. Nine of 22 hemispheres underwent surgical revascularization and ASL-4D MRA was repeated postoperatively.

RESULTS

Time-resolved inflow of blood through the cerebral vessels, including moyamoya vessels, was visualized in all the 22 non-operated hemispheres. MMD stages assessed by DSA and ASL-4D MRA were completely matched in 18 hemispheres, with a significant positive correlation between these modalities (r=0.93, P<0.001). Inter-observer agreement with ASL-4D MRA (κ=0.91±0.04, P<0.001) and inter-modality agreement between ASL-4D MRA and DSA (κ=0.93±0.04, P<0.001) were both excellent. MMD stages assessed by ASL-4D MRA have also a significant positive correlation with those assessed by TOF MRA (r=0.68, P=0.004). Repeated ASL-4D MRA clearly demonstrated the bypassed arteries and changes in the dynamic flow patterns of cerebral arteries in all the nine hemispheres after surgical revascularization. Of these, postoperative focal hyperperfusion was detected by single photon emission tomography in 7 hemispheres. In five of the seven hemispheres (71%) with postoperative hyperperfusion, ASL-4D MRA demonstrated focal hyperintense signals in the bypassed arteries, although TOF MRA did not.

CONCLUSIONS

Noninvasive ASL-4D MRA is feasible for the diagnosis of MMD staging. This next generation angiography may be useful for monitoring disease evolution and treatment response in cerebral arteries after revascularization surgery in MMD.

Surgical Outcomes for Cervical Carotid Artery Stenosis: Treatment Strategy for Bilateral Cervical Carotid Artery Stenosis

BACKGROUND

Carotid endarterectomy (CEA) and carotid stenting (CAS) are beneficial procedures for patients with high-grade cervical carotid stenosis. However, it is sometimes difficult to manage patients with bilateral carotid stenosis. To decide the treatment strategy, one of the most important questions is whether contralateral stenosis increases the risk of patients undergoing CEA.

METHODS

This retrospective study included 201 patients with carotid stenosis who underwent a total of 219 consecutive procedures (CEA 189/CAS 30). We retrospectively analyzed outcomes in patients with carotid stenosis who were treated with either CEA or CAS and evaluated whether or not contralateral lesions increases the risk of patients undergoing CEA or CAS. Furthermore, we retrospectively verified our treatment strategy for bilateral carotid stenosis.

RESULTS

The incidences of perioperative complications were 5.3% in the CEA patients and 6.7% in the CAS patients, respectively. There was no significant difference between these 2 groups. The existences of contralateral occlusion and/or contralateral stenosis were not associated with perioperative complications in both the groups. There were 32 patients with bilateral severe carotid stenosis (>50%). Of those, 13 patients underwent bilateral revascularizations; CEA followed by CEA in 8, CEA followed by CAS in 3, CAS followed by CEA + coronary artery bpass grafting in 1, and CAS followed by CAS in 1.

CONCLUSIONS

Our date showed that the existence of contralateral carotid lesion was not associated with perioperative complications, and most of our cases with bilateral carotid stenosis initially underwent CEA.

Abstract T MP55: Utility of 4D-MRA to Measure Blood Flow Velocity in Cerebral Major Arteries

Transcranial Doppler is widely used clinically to measure blood flow velocity (BFV) in cerebral major arteries. This method, however, has a limitation in that its successful measurement depends on the accessibility of patients’ cranial window and the technical ability of operators. We therefore developed a novel method to measure BFV in cerebral major arteries with 4D-MRA, which was less susceptible to patients and the conditions of the operators.

Methods: 4D-MRA was performed with a 3T MR unit (Achieva TX; Philips Medical Systems) using arterial spin labeling methods. The blood flow through the internal carotid arteries (ICA) and the basilar artery (BA) within imaging range was visualized by using look-locker readout methods. BFV was calculated by dividing the flow distance traveled in the arteries by the time elapsed. BFV of 34 patients (non-vascular disease:11, ICA stenotic disease:6, moyamoya disease:9, and cerebral aneurysm:8) were measured using the 4D-MRA method and the 2D phase contrast method.

Results: In the case of patients with non-vascular diseases, mean BFV of the right ICA, the left ICA, and the BA was 24.5±7.0, 23.3±6.9, and 17.2±5.1 cm/sec, respectively. Correlation between BFV values from the 4D-MRA method and those from the 2D phase contrast method was statistically significant (r=0.78, p<0.01). In the case of patients with ICA severe stenosis (more than 90%), BFV of the stenotic ICA was decreased to 9~11cm/sec (40~50% of BFV of the contralateral ICA). In the case of patients with advanced-stage moyamoya disease, BFV of the ICA was decreased to 9~16cm/sec (30~50% of BFV of the BA). The BFV decreases were related to CBF reduction in some cases if the development of the collateral circulation was insufficient. In the patients with aneurysm, BFV of the artery proximal to aneurysm tended to be increased except for the decrease in cavernous ICA giant aneurysm.

Conclusions: We could steadily obtain BFV in all patients by using the 4D-MRA method without any operational difficulties. In this preliminary study, we observed BFV decrease in ICA stenotic disease and moyamoya disease, and BFV increase in cerebral aneurysm. This novel 4D-MRA method to measure BFV may become a promising tool for pathophysiological evaluation of cerebrovascular diseases.

Abstract W P97: Post-ischemic Trans-arterial Regional Hypothermia Therapy Attenuates Microvascular Narrowing due to Astrocyte End-feet Swelling and Inhibits Subsequent Inflammatory Reactions in Ischemia Reperfusion Injury

Background and Purpose: We previously presented the robust neuroprotective effects of post-ischemic trans-arterial regional hypothermia therapy in I/R injury model rats (ISC 2014, San Diego). This treatment showed a significant suppression of infarct volume and inflammatory reaction at 24hrs after reperfusion. To characterize the neuroprotective effects in terms of microvascular integrity, we investigated microvascular morphological changes and inflammatory reactions by a time course analysis within 24hrs.

Methods: At reperfusion onset, 2hr-MCAO rats were divided into cold saline group (10°C, 20ml/kg of trans-arterial infusion from the recanalized artery for 15mins), warm saline group (37°C, in the same manner as cold saline group), and control group (recanalization only). Microvascular morphological changes were examined by vWF Immunohistochemistry (IHC) and transmission electron microscopy (TEM), and inflammatory reactions were examined by Western blotting and IHC at the time point of 0hr, 2hrs, 6hrs, and 24hrs of reperfusion.

Results: IHC analysis and TEM observation revealed that astrocyte end-feet swelling occurred at 2hrs and progressed to 6hrs, and microvascular narrowing due to the swelling occurred at 6hrs in control group. This microvascular morphological change was attenuated in cold saline group. While endothelial ICAM1 overexpression started at 6hrs in control group, MPO, MMP9, and Iba-1 overexpression occurred only at 24hrs in the same group. These inflammatory reactions were also inhibited in cold saline group.

Conclusions: Post-ischemic trans-arterial regional hypothermia therapy attenuated astrocyte end-feet swelling from 2hrs and the swelling induced microvascular narrowing at 6hrs. The treatment also inhibited endothelial ICAM-1 overexpression at 6hrs, and subsequently inhibited inflammatory reactions at 24hrs. The maintenance of microvascular morphological and functional integrity may be the primary cause of the neuroprotective effects by the regional hypothermia.

Abstract 136: Prediction of Postoperative Hyperperfusion by Intraoperative Assessment of Indocyanine Green Videoangiography in Moyamoya Disease

Background: Postoperative hyperperfusion is a potential complication of the direct bypass procedure for moyamoya disease (MMD). However, no reliable modality is available yet for the prediction of postoperative hyperperfusion during surgery for MMD. This study aimed to investigate whether semiquantitative analysis of indocyanine green (ICG) videoangiography could contribute to the prediction of postoperative hyperperfusion in MMD.

Methods: This study included 12 hemispheres from 10 patients who underwent surgical revascularization for MMD. Intraoperative ICG videoangiography was performed before and after a direct bypass procedure. The ICG intensity-time curves were semiquantitatively analyzed to evaluate cortical perfusion by calculating the blood flow index (BFI). Using single-photon emission computed tomography (SPECT), postoperative cerebral blood flow measurements were performed thrice: immediately and 2 and 7 days after surgery.

Results: BFI significantly increased from 21.3 ± 10.5 to 38.4 ± 20.0 after bypass procedures in all the hemispheres (p < 0.01). The ratio of BFI before and after the bypass procedure was 2.4 ± 2.0, ranging from 0.5 to 8.0. Postoperative hyperperfusion was observed in 9 of the 12 operated hemispheres within 7 days after surgery. Of these, 3 hemispheres developed hyperperfusion immediately after surgery. In the adult cases, the increase in the ratio of BFI after bypass was significantly greater in those who developed hyperperfusion immediately after surgery than in those who did not (6.5 ± 0.5 vs. 1.8 ± 2.1, p < 0.01). In contrast, no significant increase in BFI was observed in the pediatric MMD patients who experienced immediate hyperperfusion. No correlation between the changes in BFI and the occurrence of delayed hyperperfusion was observed.

Conclusions: Our results suggest that semiquantitative analysis of BFI by intraoperative ICG videoangiography is useful in evaluating changes in cortical perfusion after bypass procedures for MMD and can predict the occurrence of early-onset hyperperfusion in MMD patients after direct bypass.

Abstract T MP59: Symptomatic and Silent Cerebral Infarct following Combined Bypass for Moyamoya Disease evaluated with Diffusion-Weighted Image: A Multivariate Analysis

Background: The clinical features of cerebral infarct detected by diffusion-weighted image (DWI) following combined direct and indirect bypass for moyamoya disease (MMD) is still not fully understood. This study aims to study the incidence and risk correlates of symptomatic and silent cerebral infarct following combined bypass in MMD.

Methods: A retrospective survey was conducted with a sample size of 95 consecutive patients with MMD treated by combined bypass in Hokkaido University since 2002. DWI that was evaluated within 2 weeks after surgery was available in 111 of 131 surgeries (85%). Demographics, preoperative radiological findings, procedure-related data and postoperative symptomatic hyperperfusion were assessed. A multivariate logistic regression analysis was used to study the related variables on postoperative cerebral infarct on DWI.

Results: Postoperative DWI detected a total of 21 instances (18.9%/surgery) of cerebral infarct, with no significant difference between generations (21.9 and 13.2%/surgery in adults and pediatrics, respectively). Symptomatic and silent cerebral infarct was occurred more frequently when surgery was performed following the ischemic events within 6 months prior to the surgery (recent ischemic events) compared to when performed without the recent ones (15.3 and 3.6%/surgery, respectively, P = 0.0078). Preemptive antiplatelet use and procedure-related variables, including craniotomy size and the number of direct bypass did not have any relationships with cerebral infarct. After adjustment of above-mentioned variables, symptomatic and silent cerebral infarct was found to associate significantly with recent ischemic events (P = 0.032; OR = 5.5; 95%CI 1.2-26) and preoperative FLAIR ivy sign (P = 0.047; OR = 5.9; 95%CI 1.02-33.9). Cerebral infarct detected by DWI was likely to be observed beyond the area covered by combined bypass.

Conclusions: Symptomatic and silent cerebral infarct occurred in 18.9% of combined bypasses for MMD. It may be associated with recent ischemic events and preoperative FLAIR ivy sign. Surgical management to avoid postoperative infarct after the combined bypass beyond the bypassed area would be essential to further improve the outcome of ischemic type of MMD.

Abstract 38: Intensive Monitoring of Cardiac Function and Extravascular Lung Water Predicts Outcome of Tako-tsubo Cardiomyopathy after Subarachnoid Hemorrhage

Takotsubo cardiomyopathy (TCM) is a life-threatening systemic consequence early after subarachnoid hemorrhage (SAH), but precise hemodynamics and related outcome are not well-understood. We aimed to investigate the TCM-induced cardiac function by transpulmonary thermodilution and its impact on clinical outcome of SAH. Forty-six consecutive SAH patients who developed TCM and treated surgically or endovascularly were analyzed retrospectively. Patients were divided into two groups of LVEF <40% (TCM with LV dysfunction) and LVEF ≥40% (TCM without LV dysfunction). Cardiac function index (CFI) and extravascular lung water index (ELWI) were monitored by transpulmonary thermodilution. Transpulmonary thermodilution-derived CFI was correlated significantly with echocardiographic left ventricular ejection fraction (LVEF) ( r = 0.82, P <0.0001). The CFI between day 0 to day 7 was significantly lower in patients with LV dysfunction (LVEF <40%) than in patients with LVEF ≥40% ( P <0.05). CFI had a better ability than cardiac output to detect cardiac dysfunction (LVEF <40%) (Area under the curve: 0.85 ± 0.02; P <0.001). A CFI value of <4.2 min -1 had a sensitivity of 82% and specificity of 84% for detecting LVEF <40%. The CFI <4.2 min -1 was associated with delayed cerebral ischemia (DCI) (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.33-2.86; P = 0.004) and poor 3-month functional outcome on modified Rankin Scale of 4-6 (OR, 1.87; 95% CI, 1.06-3.29; P = 0.02). An ELWI >14 mL/kg after day 4 increased the risk of poor functional outcome at 3-month follow-up (OR, 2.10; 95% CI, 1.11-3.97; P = 0.04). In conclusion, prolonged cardiac dysfunction and pulmonary edema increased the risk of DCI and poor 3-month functional outcome in patients with SAH suffering from TCM. Serial measurements of CFI and ELWI by transpulmonary thermodilution may provide an easy bedside method of detecting early changes of the cardiopulmonary function in directing proper post-SAH treatment.

Abstract W P73: Inside Intramural Thrombus Formation with Inflammatory Reactions Is Relevant to the Rupture of Cerebral Aneurysms

Background and Purpose: Although recent researches on cerebral aneurysms (CAs) have been performed with the hydrodynamic or the molecular biological technique, the mechanisms of rupture are not fully understood. The aim of this study is to assess the mechanism by a comparison between ruptured and un-ruptured CAs with histopathological and electron-microscopic analysis.

Methods: We analyzed 33 CAs (24 ruptured, 9 un-ruptured) collected surgically after neck clipping. As for the ruptured CAs, we operated them within 24 hours from the onset. HE staining, Elastica Masson staining, PTAH staining, and CD68 immunohistochemical staining were performed with paraffin sections. Morphological analysis with Scanning Electron Microscopy (SEM) was performed with 6 CAs (3 ruptured, 3 un-ruptured).

Results: The common histopathological finding in both ruptured and un-ruptured CAs was that the aneurysmal wall consisted mostly of thick collagen layer without normal internal elastic lamina and media. The characteristic histopathological finding in ruptured CAs was inside intramural thrombus formation with infiltration of CD68 positive cells at the rupture point. The common SEM finding in both ruptured and un-ruptured CAs was the denudation of endothelial cells and the exposure of a subendothelial amorphous or a fibrous surface. The characteristic SEM finding in ruptured CAs was the cluster formation of thick fibrin fibers with incorporation of macrophages and platelets.

Conclusions: While the endothelial denudation, the disappearance of internal elastic lamina and media, and the predominance of collagen layer in the aneurysmal wall were common in both ruptured and un-ruptured CAs, inside intramural thrombus formation with inflammatory reactions was characteristic only in ruptured CAs. This result suggests that thrombo-inflammatory reactions in CAs may act as a trigger for ruptures.

Abstract T P226: Cilostazol Can Attenuate Oxidative Stress by Suppressing Nox2 on Neurons in Mice Permanent Focal Ischemia

It has been reported that phosphodiesterase (PDE) 3 inhibitor cilostazol, which is used as an antiplatelet drug, could ameliorate ischemic brain injury. We aimed to investigate how cilostazol affected permanent focal ischemia. Male Balb/c mice were subjected to permanent middle cerebral artery occlusion. They were treated with cilostazol (10- mg/kg or 20-mg/kg) or vehicle 30 min and 24 h post-ischemia, and the infarct volume was assessed 48 h post-ischemia. The animals treated with 20-mg/kg cilostazol or vehicle were sacrificed 6 h or 24 h post-ischemia, and then the immunohistochemistry was performed to the brain sections. We demonstrated that the treatment with 20- mg/kg cilostazol significantly reduced infarct volume (70.1% vs. vehicle group). Immunohistochemistry against 8-hydroxydeoxyguanosine (OHdG) showed that some neurons suffered from oxidative stress in peri-infarct 6 h post-ischemia. The treatment with cilostazol reduced the number of 8-OHdG-positive neurons significantly (65.8 ± 33.5% in vehicle group and 21.3 ± 9.9% in cilostazol group). Moreover, the number of NADPH oxidase (NOX) 2-positive neurons was also reduced significantly (57.0 ± 13.6% in vehicle group and 26.5 ± 16.7% in cilostazol group). On the other hand, immunohistochemistry against phosphorylated cyclic-AMP response element binding protein (pCREB) showed that the number of the pCREB-positive neurons in peri-infarct of the cilostazol-treated animals was significantly higher than in vehicle-treated ones 24 h post-ischemia. These findings suggested that cilostazol could have multi-mechanisms to ameliorate the tissue damage, one was to attenuate oxidative stress by suppressing NOX2 on ischemic neurons, and another was anti-apoptotic effect through the pathway of Akt/pCREB.

Chronic ischemia alters brain microstructural integrity and cognitive performance in adult moyamoya disease

BACKGROUND AND PURPOSE

The mechanisms underlying frontal lobe dysfunction in moyamoya disease (MMD) are unknown. We aimed to determine whether chronic ischemia induces subtle microstructural brain changes in adult MMD and evaluated the association of changes with neuropsychological performance.

METHODS

MRI, including 3-dimensional T1-weighted imaging and diffusion tensor imaging, was performed in 23 adult patients with MMD and 23 age-matched controls and gray matter density and major diffusion tensor imaging indices were compared between them; any alterations in the patients were tested for associations with age, ischemic symptoms, hemodynamic compromise, and neuropsychological performance.

RESULTS

Decrease in gray matter density, associated with hemodynamic compromise (P<0.05), was observed in the posterior cingulate cortex of patients with MMD. Widespread reduction in fractional anisotropy and increases in radial diffusivity and mean diffusivity in some areas were also observed in bilateral cerebral white matter. The fractional anisotropy (r=0.54; P<0.0001) and radial diffusivity (r=-0.41; P<0.01) of white matter significantly associated with gray matter density of the cingulate cortex. The mean fractional anisotropy of the white matter tracts of the lateral prefrontal, cingulate, and inferior parietal regions were significantly associated with processing speed, executive function/attention, and working memory.

CONCLUSIONS

In adult MMD, there were more white matter abnormalities than gray matter changes. Disruption of white matter may play a pivotal role in the development of cognitive dysfunction.

Short-, middle- and long-term safety of superparamagnetic iron oxide-labeled allogeneic bone marrow stromal cell transplantation in rat model of lacunar infarction

Recently, both basic and clinical studies demonstrated that bone marrow stromal cell (BMSC) transplantation therapy can promote functional recovery of patients with CNS disorders. A non-invasive method for cell tracking using MRI and superparamagnetic iron oxide (SPIO)-based labeling agents has been applied to elucidate the behavior of transplanted cells. However, the long-term safety of SPIO-labeled BMSCs still remains unclear. The aim of this study was to investigate the short-, middle- and long-term safety of the SPIO-labeled allogeneic BMSC transplantation. For this purpose, BMSCs were isolated from transgenic rats expressing green fluorescent protein (GFP) and were labeled with SPIO. The Na/K ATPase pump inhibitor ouabain or vehicle was stereotactically injected into the right striatum of wild-type rats to induce a lacunar lesion (n = 22). Seven days after the insult, either BMSCs or SPIO solution were stereotactically injected into the left striatum. A 7.0-Tesla MRI was performed to serially monitor the behavior of BMSCs in the host brain. The animals were sacrificed after 7 days (n = 7), 6 weeks (n = 6) or 10 months (n = 9) after the transplantation. MRI demonstrated that BMSCs migrated to the damage area through the corpus callosum. Histological analysis showed that activated microglia were present around the bolus of donor cells 7 days after the allogeneic cell transplantation, although an immunosuppressive drug was administered. The SPIO-labeled BMSCs resided and started to proliferate around the route of the cell transplantation. Within 6 weeks, large numbers of SPIO-labeled BMSCs reached the lacunar infarction area from the transplantation region through the corpus callosum. Some SPIO nanoparticles were phagocytized by microglia. After 10 months, the number of SPIO-positive cells was lower compared with the 7-day and 6-week groups. There was no tumorigenesis or severe injury observed in any of the animals. These findings suggest that BMSCs are safe after cell transplantation for the treatment of stroke.

Impact of transpulmonary thermodilution-based cardiac contractility and extravascular lung water measurements on clinical outcome of patients with Takotsubo cardiomyopathy after subarachnoid hemorrhage: a retrospective observational study

Introduction

Takotsubo cardiomyopathy (TCM) is a life-threatening systemic consequence early after subarachnoid hemorrhage (SAH), but precise hemodynamics and related outcomes have not been studied. The purpose of this study was to investigate TCM-induced cardiac function by transpulmonary thermodilution and its impact on clinical outcome of SAH.

Methods

We retrospectively analyzed 46 consecutive postoperative SAH patients who developed TCM. Patients were divided into two groups of echocardiographic left ventricular ejection fraction (LVEF) <40% (TCM with left ventricular (LV) dysfunction) and LVEF ≥40% (TCM without LV dysfunction). Cardiac function index (CFI) and extravascular lung water index (ELWI) were monitored by transpulmonary thermodilution in parallel with serial measurements of echocardiographic parameters and blood biochemical markers.

Results

Transpulmonary thermodilution-derived CFI was significantly correlated with LVEF (r = 0.82, P < 0.0001). The CFI between days 0 and 7 was significantly lower in patients with LV dysfunction (LVEF <40%) than in patients with LVEF ≥40% (P < 0.05). CFI had a better ability than cardiac output to detect cardiac dysfunction (LVEF <40%) (area under the curve = 0.85 ± 0.02; P < 0.001). A CFI value <4.2 min⁻¹ had a sensitivity of 82% and specificity of 84% for detecting LVEF <40%. CFI <4.2 min⁻¹ was associated with delayed cerebral ischemia (DCI) (odds ratio (OR) = 2.14, 95% confidence interval (CI) = 1.33 to 2.86; P = 0.004) and poor 3-month functional outcome on a modified Rankin Scale of 4 to 6 (OR = 1.87, 95% CI = 1.06 to 3.29; P = 0.02). An extravascular lung water index (ELWI) >14 ml/kg after day 4 increased the risk of poor functional outcome at 3-month follow-up (OR = 2.10, 95% CI = 1.11 to 3.97; P = 0.04).

Conclusions

Prolonged cardiac dysfunction and pulmonary edema increased the risk of DCI and poor 3-month functional outcome in postoperative SAH patients with TCM. Serial measurements of CFI and ELWI by transpulmonary thermodilution may provide an easy bedside method of detecting early changes in cardiopulmonary function to direct proper post-SAH treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0482-4) contains supplementary material, which is available to authorized users.

The frequency of postoperative stroke in moyamoya disease following combined revascularization: a single-university series and systematic review

Object

Although combined direct and indirect anastomosis in patients with moyamoya disease immediately increases cerebral blood flow, the surgical procedure is more complex. Data pertinent to the postoperative complications associated with combined bypass are relatively scarce compared with those associated with indirect bypass. This study investigated the incidence and characteristics of postoperative stroke in combined bypass and compared them with those determined from a literature review to obtain data from a large population.

Methods

A total of 358 revascularization procedures in 236 patients were retrospectively assessed by reviewing clinical charts and radiological data. PubMed was searched for published studies on surgical treatment to determine the incidence of postoperative complications in a larger population.

Results

Seventeen instances of postoperative stroke were observed in 16 patients (4.7% per surgery, 95% CI 2.8%–7.5%). Postoperative stroke was more frequent (7.9% per surgery) in adults than in pediatric patients (1.7% per surgery, OR 4.07, 95% CI 1.12–14.7; p < 0.05). Acute progression of stenoocclusive changes were identified in the major cerebral arteries (anterior cerebral artery, n = 3; middle cerebral artery, n = 1; posterior cerebral artery, n = 2). The postoperative stroke rate was comparable with that (5.4%) determined from a literature search that included studies reporting more than 2000 direct/combined procedures. No differences in the stroke rates between the direct/combined and indirect procedures were found. In the literature review, direct/combined bypass was more often associated with excellent revascularization (angiographic opacification greater than two-thirds) than indirect bypass (p < 0.05).

Conclusions

This experience of 358 consecutive procedures is one of the largest series for which the postoperative stoke rate for direct/combined bypass performed with a unified strategy has been reported. A systematic review confirmed that the postoperative stroke rate for the direct/combined procedure was comparable to that for the indirect procedure.

Impact of cervical internal carotid clamping and radial artery graft bypass on cortical arterial perfusion pressure during craniotomy

Strategic cervical internal carotid occlusion is employed either temporarily or permanently in various neurosurgical procedures. The aim of the present study was to assess changes in cortical arterial pressure during cervical internal carotid cross-clamping before and after the placement of radial artery (RA) graft bypass in the treatment of complex carotid artery aneurysms. Perfusion pressure of the middle cerebral artery (MCA) was assessed in 22 patients with complex carotid aneurysm treated with RA graft bypass. Regional cerebral blood flow was assessed postoperatively using single-photon computed tomography. Mean cortical blood pressure (mcBP) was found to be 48.2 ± 24.2 and 97.0 ± 24.0 % of baseline after clamping the cervical internal carotid artery and opening the RA graft bypass, respectively. Cerebral perfusion pressure estimated by the mcBP failed to sustain a critical limit of greater than 70 mmHg under craniotomy in 16 out of 20 (80 %) patients. There was an inverse correlation in mcBP between the baseline and after the placement of the RA graft bypass (r = 0.66, P < 0.005). Postoperative regional cerebral blood flow in the MCA territory on the ipsilateral side of the aneurysm was 97 ± 7 % of that of the contralateral side after internal carotid artery (ICA) ligation combined with RA graft bypass. Substantial pressure reductions in cerebral cortical arteries were observed during the cervical internal carotid cross-clamping. Perfusion pressure in peripheral cortical arteries after the placement of the RA graft bypass was comparable to the state before ICA clamping.