Background: Postoperative hyperperfusion syndrome (PHS) is a well-known complication following superficial temporal artery (STA)-middle cerebral artery (MCA) bypass for moyamoya disease (MMD). The early detection of postoperative radiological hyperperfusion (PRH), characterized by a transient increase in local cerebral blood flow (CBF), is crucial for the early diagnosis of PHS. This study aimed to investigate the effectiveness of waveform analysis for early PRH detection.
Methods: We reviewed 52 consecutive patients who underwent STA-MCA bypass for MMD. Patients were divided into PRH and non-PRH groups based on the postoperative/preoperative CBF ratio. We collected the intraoperative bypass graft waveform and bypass flow data using a flowmeter. The pulsatile index (PI), an indicator of peripheral vascular resistance (PVR), was calculated from bypass flow data. Next, the newly proposed index of PVR, the ratio of the time from peak to 50% decay and to 100% decay (RT50), was calculated through waveform analysis. The values were then compared between the PRH and non-PRH groups.
Results: Twenty-seven of the 52 patients met the inclusion criteria. Fourteen of these 27 patients showed PRH. The RT50, but not the PI, was significantly higher in the PRH group. Linear regression analysis revealed a significant correlation between the RT50 and PI. In the receiver operating characteristic for predicting PRH, the area under the curve of RT50 was 0.750, with a cutoff value of 0.255, a sensitivity of 0.928, and a specificity of 0.500.
Conclusions: The RT50 obtained from waveform analysis is associated with PVR and can be useful for the early detection of PRH in patients with MMD.
Introduction: Enlarged perivascular spaces (EPVS) are considered early manifestations of impaired clearance mechanisms in the brain; however, it is unclear whether EPVS they are associated with the development of malignant cerebral edema (MCE) after large hemispheric infarction (LHI). Therefore, we investigated the predictive value of EPVS in predicting MCE in LHI.
Methods: Patients suffering from acute LHI were consecutively enrolled. EPVS were rated after the stroke with validated rating scales from magnetic resonance imagess. Patients were divided into two groups according to the occurrence of MCE. Logistic regression was used to analyze the relationship between EPVS and MCE in the basal ganglia (BG) and centrum semiovale (CS) regions. Receiver operating characteristic (ROC) curves assessed the ability of EPVS individually and with other factors in predicting MCE.
Results: We included a total of 255 patients, of whom 98 were MCE patients (58 [59.2%] males, aged 70 [range=61.75-78] years) and found that atrial fibrillation, National Institutes of Health Stroke Scale score, infarct volume, neutrophil-lymphocyte ratio, and moderate-to-severe CS-EPVS were positively associated with MCE. After adjusting for confounds, moderate-to-severe CS-EPVS remained independent risk factor of MCE (odds ratio=16.212, p<0.001). According to the ROC analysis, MCE was highly suspected when CS-EPVS > 14 (sensitivity=0.82, specificity=0.48), and the guiding value were higher when CS-EPVS combined with other MCE predictors (area under the curve=0.90, sensitivity=0.74, specificity=0.90).
Conclusion: CS-EPVS were important risk factor for MEC in patients with acute LHI and can help identify patients at risk for MCE.
Introduction: Revascularization surgery is recommended for all pediatric patients with moyamoya disease (MMD) with ischemic symptoms because the brains of such patients are still developing. By contrast, no clear guidelines for selective revascularization surgery in adult patients (30 years or more) with ischemic presentation have been established. Regarding the age of initial onset of ischemic MMD, patients in their 20s are at the bottom of the distribution and this age group may share features with both adult and pediatric patients. The present prospective study aimed to clarify the clinical features and treatment outcomes of patients in their 20s (younger patients) with ischemic MMD compared with patients aged 30-60 years (older patients).
Methods: While patients with misery perfusion in the symptomatic cerebral hemisphere on 15O-positron emission tomography underwent combined surgery including direct and indirect revascularizations in the first study period and indirect revascularization alone in the second study period, patients without misery perfusion in that hemisphere received pharmacotherapy alone through the two study periods. Cerebral angiography via arterial catheterization and neuropsychological testing were performed before and after surgery.
Results: During 12 years, 12 younger patients were included and comprised 6% of all adult patients (194 patients). The incidence of misery perfusion in the affected hemisphere was significantly higher in younger (12/12 [100%]) than in older patients (57/182 [31%]) (p < 0.0001). No difference in the incidence of cerebral hyperperfusion syndrome and postoperatively declined cognition was seen between younger (2/5 [40%] and 2/5 [40%], respectively) and older (11/36 [31%] and 15/36 [42%], respectively) cerebral hemispheres undergoing combined revascularization surgery. No difference in the incidence of postoperatively formed collateral flows feeding more than one-third of the middle cerebral artery cortical territory on angiograms and postoperatively improved cognition was seen between younger (9/10 [90%] and 6/10 [60%], respectively) and older (18/22 [83%] and 14/22 [64%], respectively) cerebral hemispheres undergoing indirect revascularization surgery alone.
Conclusion: Patients in their 20s with ischemic MMD always exhibit misery perfusion in the affected hemisphere, unlike older patients, and sometimes develop cerebral hyperperfusion syndrome after combined revascularization surgery, leading to cognitive decline, similar to older patients. Moreover, indirect revascularization surgery alone forms sufficient collateral circulation and restores cognitive function in patients in their 20s, similar to older patients.
Introduction: In emergency rooms (ERs), 5% of patients experiencing an acute ischemic stroke (AIS) receive an alternative diagnosis; these cases are known as stroke chameleons (SC). The percentage of SC treated with intravenous thrombolysis (IVT) and the characteristics have not been well described. We aimed at investigating the variables associated with the probability receiving IVT.
Methods: In this prospective study, we included consecutive patients with SC admitted at the ER of Clínica Alemana between September 2014 and October 2023.
Results: Among 1,193 stroke patients; sixty-three (5.2%) corresponded to SC. Ten of these cases (15.8%, 95% CI: 8.8-26.8) were treated with IVT, mean door-to-needle (DTN) time of 85.7 (SD 35) min, median of 73.5 (IQR 62-113) min. SCs who underwent IVT were younger (p = 0.01), with higher NIHSS (p = 0.05). They presented more frequently with altered level of consciousness in the NIHSS (p = 0.01), language abnormities (p = 0.001), and dysarthria (p = 0.01). In multivariate analysis, none of the variables were significantly associated with IVT. A secondary analysis showed that only time to brain imaging was significantly associated with IVT (OR: 0.99; 95% CI: 0.98-0.99; p = 0.01).
Conclusions: Almost 1 out of every 7 SC could be treated with IVT but with a prolonged DTN time; the chance of being treated is associated with time to brain imaging.
Introduction: In emergency rooms (ERs), 5% of patients experiencing an acute ischemic stroke (AIS) receive an alternative diagnosis; these cases are known as stroke chameleons (SC). The percentage of SC treated with intravenous thrombolysis (IVT) and the characteristics have not been well described. We aimed at investigating the variables associated with the probability receiving IVT.
Methods: In this prospective study, we included consecutive patients with SC admitted at the ER of Clínica Alemana between September 2014 and October 2023.
Results: Among 1,193 stroke patients; sixty-three (5.2%) corresponded to SC. Ten of these cases (15.8%, 95% CI: 8.8-26.8) were treated with IVT, mean door-to-needle (DTN) time of 85.7 (SD 35) min, median of 73.5 (IQR 62-113) min. SCs who underwent IVT were younger (p = 0.01), with higher NIHSS (p = 0.05). They presented more frequently with altered level of consciousness in the NIHSS (p = 0.01), language abnormities (p = 0.001), and dysarthria (p = 0.01). In multivariate analysis, none of the variables were significantly associated with IVT. A secondary analysis showed that only time to brain imaging was significantly associated with IVT (OR: 0.99; 95% CI: 0.98-0.99; p = 0.01).
Conclusions: Almost 1 out of every 7 SC could be treated with IVT but with a prolonged DTN time; the chance of being treated is associated with time to brain imaging.
Background: Many unusual and fascinating causes of stroke are seen in Asia. Although rarely encountered in the Western world, such cases are seen not so infrequently by neurologists, physicians, and other healthcare workers in Asian countries. This article highlights some of these intriguing causes of stroke such as snakebite, scorpion stings, and bee and wasp stings.
Summary: Snakebite is a neglected tropical disease of global importance affecting over 5 million people each year, and scorpion stings and bee and wasp stings affect over a million people worldwide every year. Strokes due to these uncommon causes predominantly affect young males in their most productive years, and many victims die or remain with residual disability with significant socioeconomic consequences to the affected families and society. Both ischaemic and haemorrhagic strokes are seen, with ischaemic strokes being more common. Many unanswered questions remain regarding the pathophysiological mechanisms, clinical spectrum, and the natural history of stroke due to these causes. Antivenom is effective in snake envenoming, antivenom and prazosin are effective in scorpion envenoming, and treatment of anaphylaxis and allergy is recommended in systemic reactions due to bee or wasp stings. However, there are no treatment guidelines or expert recommendations to guide the management of stroke in these patients, and there are no data on the safety and efficacy of stroke-specific treatments such as antiplatelet therapy, thrombolysis or endovascular treatment.
Key messages: More research is clearly needed to unravel the complexities related to stroke following snakebite, scorpion envenoming, and bee and wasp stings, and to guide the development of optimal stroke treatment strategies in these unusual situations. Awareness of these exotic stroke aetiologies is important in early recognition and appropriate management of patients presenting with stroke symptoms in Asian countries, and in global travellers from the region. International collaborations would go a long way in improving our understanding of these rare but fascinating causes of stroke.
Introduction: Diffusion-weighted imaging (DWI) plays a crucial role in acute ischemic stroke (AIS), as it is used to evaluate the ischemic lesions that are irreversibly damaged. The reversibility of DWI ischemic lesions has been noted in patients with AIS who undergo revascularization therapy. In addition, the occurrence of this phenomenon in large ischemic regions remains rare, particularly the near-complete reversal of large DWI lesion cases.
Case presentation: A 58-year-old male presented with a generalized tonic-clonic seizure. Emergent magnetic resonance imaging (MRI) revealed an extremely large infarction lesion in the right hemisphere with an Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) value of 2 and occlusion of the terminal right internal carotid artery. The patient was immediately transferred to the Digital Subtraction Angiography (DSA) Unit for endovascular treatment with a stent retriever. After a rapid successful reperfusion with expanded treatment in cerebral infarction (eTICI) score of 3, the patient promptly recovered 24 h after the procedure. A brain MRI was repeated after 8 days of admission, and interestingly, the DWI lesion showed significant reversal. The modified Rankin scale (mRS) at discharge was 2 and 1 at 90-day follow-up, respectively.
Conclusions: Our case shows that the reversibility of DWI ischemic lesions can occur during the acute stroke phase, even in patients with extremely large regions, if rapid and successful reperfusion is achieved. The clinical implications of this phenomenon indicate that using DWI to evaluate the infarct core should be interpreted with caution.
Introduction: Our research aimed to investigate the potential role and mechanism of lysyl oxidase (LOX)-like 2 (LOXL2) in atherosclerosis (AS) by using the human umbilical vein endothelial cells (HUVECs) stimulated by oxidized low-density lipoprotein (ox-LDL).
Methods: HUVECs were treated with ox-LDL at different concentrations (0, 10, 25, 50, and 100 μg/mL) and incubated for 24 h. The transfection efficacy of siLOXL2 was investigated by Western blot and real-time quantitative polymerase chain reaction (RT-qPCR). Cell migration, intracellular ROS measurement, oxidative stress, enzyme-linked immunosorbent assay, and adhesion assays were carried out to examine the ox-LDL-induced HUVECs injury. RT-qPCR and Western blot were used to determine gene and protein expression levels.
Results: LOXL2 protein expression increased in ox-LDL-induced endothelial cells (ECs). ox-LDL + siLOXL2 significantly inhibited the migration ability of HUVECs and reduced the expression of vascular endothelial growth factor A (VEGFA) and matrix metalloproteinase 9 gene expressions (all, p < 0.05). The ox-LDL + siLOXL2 significantly reduced intracellular ROS production and inhibited the expression of Malondialdehyde, whereas it markedly enhanced superoxide dismutase and catalase (all, p < 0.05). Supernatant levels of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were significantly attenuated by the ox-LDL + siLOXL2 treatment (all, p < 0.05). ox-LDL + siLOXL2 markedly suppressed the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 (all, p < 0.05). ox-LDL + siLOXL2 treatment remarkably reduced the expression of α-smooth muscle actin and vimentin, while increased CD31 and von Willebrand factor gene expression (all, p < 0.05).
Conclusion: LOXL2 silencing is protected against ox-LDL-induced EC dysfunction, and the mechanism may be related to the inhibition of the EndMT pathway.

