Non-Invasive Tools in Perioperative Stroke Risk Assessment for Asymptomatic Carotid Artery Stenosis with a Focus on the Circle of Willis.

This review aims to explore advancements in perioperative ischemic stroke risk estimation for asymptomatic patients with significant carotid artery stenosis, focusing on Circle of Willis (CoW) morphology based on the CTA or MR diagnostic imaging in the current preoperative diagnostic algorithm. Functional transcranial Doppler (fTCD), near-infrared spectroscopy (NIRS), and optical coherence tomography angiography (OCTA) are discussed in the context of evaluating cerebrovascular reserve capacity and collateral vascular systems, particularly the CoW. These non-invasive diagnostic tools provide additional valuable insights into the cerebral perfusion status. They support biomedical modeling as the gold standard for the prediction of the potential impact of carotid artery stenosis on the hemodynamic changes of cerebral perfusion. Intraoperative risk assessment strategies, including selective shunting, are explored with a focus on CoW variations and their implications for perioperative ischemic stroke and cognitive function decline. By synthesizing these insights, this review underscores the potential of non-invasive diagnostic methods to support clinical decision making and improve asymptomatic patient outcomes by reducing the risk of perioperative ischemic neurological events and preventing further cognitive decline.

Bilateral simultaneous thalamic hematomas - Unusual presentation of intracerebral hemorrhage: A case report.

Background: Bilateral symmetrical simultaneous thalamic hemorrhages are extremely rare. Case presentation: A 52-year-old female patient with a history of untreated hypertension, ischemic heart disease and type 2 diabetes mellitus was admitted with somnolence, disorientation, 3/5 right-sided hemiparesis and blood pressure of 200/110 mmHg. Cranial CT scan showed bilateral thalamic hemorrhages, with bilateral intraventricular propagation and subarachnoid component along the frontal, parietal and occipital lobes. CT angiography did not show any source of bleeding or cerebral vein or sinus thrombosis. Coagulation laboratory parameters were in normal range.The patient was treated with a combination of intravenous and oral antihypertensive medication; five days later she become normotensive with improving motor function but was still somnolent.Six weeks later she was fully alert, motor functions continued to improve, but had severe cognitive deficit. Repeated neuropsychological assessment showed a slow and moderate improvement of a major neurocognitive impairment. At discharge her Mini Mental State Examination score was 13/30 and Addenbrooke's Cognitive Examination III score was 42/100.Cranial MRI scan eight weeks later depicted subacute-chronic stages of the bilateral hemorrhages, regression of perifocal edema, cerebral microbleeds in the left external capsule and the pons.At discharge after 2 months, she was alert, had no focal neurological signs, but was unable to care for herself due to lack of motivation, spatial and temporal disorientation and severe cognitive deficit. Conclusion: Simultaneous bilateral thalamic hemorrhages are extremely rare, the most commonly observed symptom is cognitive impairment. Our case was caused by hypertensive crisis, but in the differential diagnosis, sinus thrombosis, hemorrhagic transformation of ischemic stroke and various hemophilias should be considered.

Impaired cerebrovascular reactivity correlates with reduced retinal vessel density in patients with carotid artery stenosis: Cross-sectional, single center study.

BACKGROUND: The cerebral and retinal circulation systems are developmentally, anatomically, and physiologically interconnected. Thus, we hypothesized that hypoperfusion due to atherosclerotic stenosis of the internal carotid artery (ICA) can result in disturbances of both cerebral and retinal microcirculations. We aimed to characterize parameters indicating cerebrovascular reactivity (CVR) and retinal microvascular density in patients with ICA stenosis, and assess if there is correlation between them. METHODS: In this cross-sectional study the middle cerebral artery (MCA) blood flow velocity was measured by transcranial Doppler (TCD) and, simultaneously, continuous non-invasive arterial blood pressure measurement was performed on the radial artery by applanation tonometry. CVR was assessed based on the response to the common carotid artery compression (CCC) test. The transient hyperemic response ratio (THRR) and cerebral arterial resistance transient hyperemic response ratio (CAR-THRR) were calculated. Optical coherence tomography angiography (OCTA) was used to determine vessel density (VD) on the papilla whole image for all (VDP-WIall) and for small vessels (VDP-WIsmall). The same was done in the peripapillary region: all (VDPPall), and small (VDPPsmall) vessels. The VD of superficial (VDMspf) and deep (VDMdeep) macula was also determined. Significance was accepted when p<0.05. RESULTS: Twenty-four ICA stenotic patients were evaluated. Both CVR and retinal VD were characterized. There was a significant, negative correlation between CAR-THRR (median = -0.40) and VDPPsmall vessels (median = 52%), as well as between VDPPall vessels (median = 58%), and similar correlation between CAR-THRR and VDP-WIsmall (median = 49.5%) and between VDP-WIall (median = 55%). CONCLUSION: The significant correlation between impaired cerebrovascular reactivity and retinal vessel density in patients with ICA stenosis suggests a common mechanism of action. We propose that the combined use of these diagnostic tools (TCD and OCTA) helps to better identify patients with increased ischemic or other cerebrovascular risks.

Assessment of cerebral autoregulatory function and inter-hemispheric blood flow in older adults with internal carotid artery stenosis using transcranial Doppler sonography-based measurement of transient hyperemic response after carotid artery compression.

Unhealthy vascular aging promotes atherogenesis, which may lead to significant internal carotid artery stenosis (CAS) in 5 to 7.5% of older adults. The pathogenic factors that promote accelerated vascular aging and CAS also affect the downstream portion of the cerebral microcirculation in these patients. Primary treatments of significant CAS are eversion endarterectomy or endarterectomy with patch plasty. Factors that determine adequate hemodynamic compensation and thereby the clinical consequences of CAS as well as medical and surgical complications of carotid reconstruction surgery likely involve the anatomy of the circle of Willis (CoW), the magnitude of compensatory inter-hemispheric blood flow, and the effectiveness of cerebral microcirculatory blood flow autoregulation. This study aimed to test two hypotheses based on this theory. First, we hypothesized that patients with symptomatic and asymptomatic CAS would exhibit differences in autoregulatory function and inter-hemispheric blood flow. Second, we predicted that anatomically compromised CoW would associate with impaired inter-hemispheric blood flow compensation. We enrolled older adults with symptomatic or asymptomatic internal CAS (>70% NASCET criteria; n = 46) and assessed CoW integrity by CT angiography. We evaluated transient hyperemic responses in the middle cerebral arteries (MCA) after common carotid artery compression (CCC; 10 s) by transcranial Doppler sonography (TCD). We compared parameters reflecting autoregulatory function (e.g., transient hyperemic response ratio [THRR], return to baseline time [RTB], changes of vascular resistance) and inter-hemispheric blood flow (residual blood flow velocity). Our findings revealed that CAS was associated with impaired cerebral vascular reactivity. However, we did not observe significant differences in autoregulatory function or inter-hemispheric blood flow between patients with symptomatic and asymptomatic CAS. Moreover, anatomically compromised CoW did not significantly affect these parameters. Notably, we observed an inverse correlation between RTB and THRR, and 49% of CAS patients exhibited a delayed THRR, which associated with decreased inter-hemispheric blood flow. Future studies should investigate how TCD-based evaluation of autoregulatory function and inter-hemispheric blood flow can be used to optimize surgical techniques and patient selection for internal carotid artery revascularization.

The Effect of Circle of Willis Morphology on Retinal Blood Flow in Patients with Carotid Stenosis Measured by Optical Coherence Tomography Angiography.

The Circle of Willis (CoW) is the main collateral system, and its morphological variants are more common in patients who have severe carotid artery stenosis. Earlier data suggest that optical coherence tomography angiography (OCTA) may help to assess the changes in cerebral vascular perfusion by imaging the retinal blood flow. In this single-center prospective clinical study, patients scheduled for carotid endarterectomy (CEA) underwent preoperative computed tomography angiography (CTA) of the extra- and intracranial cerebral circulation. OCTA imaging was performed one week before surgery and postoperatively one month later. The patients were divided into two subgroups based on CTA evaluation of CoW: compromised CoW or non-compromised CoW (containing hypoplastic and normal segments). The effect of the patient's age, OCTA scan quality (SQ), CoW morphology, laterality, and surgery on superficial capillary vessel density (VD) in the macula were assessed in multivariable regression models using linear mixed models. We found that VD significantly decreased with aging (-0.12%; 95%CI: -0.07--0.15; p < 0.001) and was significantly higher in patients with non-compromised CoW morphology (by 0.87% 95%CI (0.26-1.50); p = 0.005). After CEA, retinal blood flow significantly improved by 0.71% (95%CI: 0.18-1.25; p = 0.01). These results suggest that in the case of carotid artery occlusion, patients with non-compromised CoW have more preserved ocular blood flow than subjects with compromised CoW due to remodeling of the intra-orbital blood flow. Measuring the retinal blood flow might be used as a relevant and sensitive indicator of collateral cerebrovascular circulation.

Paraneoplastic Kelch-like protein 11 antibody-associated cerebellar and limbic encephalitis caused by metastatic "burned-out" seminoma - A scar(r)y phenomenon.

INTRODUCTION: The diagnosis of paraneoplastic neurologic syndromes is challenging when the primary tumor masquerades as scar tissue (i.e. "burned-out"). METHODS: Case report. RESULTS: A 45-year-old male patient presented with progressive cerebellar symptoms and hearing loss. Initial screening for malignancy and extensive testing of paraneoplastic and autoimmune neuronal antibodies gave negative results. Repeated whole-body FDG-PET CT revealed a single paraaortic lymphadenopathy, metastasis of a regressed testicular seminoma. Anti-Kelch-like protein-11 (KLHL11) encephalitis was finally diagnosed. CONCLUSION: Our case highlights the importance of continued efforts to find an often burned-out testicular cancer in patients with a highly unique clinical presentation of KLHL11 encephalitis.

The impact of SARS-CoV-2 infection on the outcome of acute ischemic stroke-A retrospective cohort study.

BACKGROUND: Acute ischemic stroke (AIS) is a common complication of severe acute respiratory syndrome coronavirus 2 (SARS­CoV­2) infection (COVID-19), but the prognosis of these patients is poorly understood. PURPOSE: To explore the impact of COVID-19 on neurological outcomes in AIS patients. METHODS: A comparative retrospective cohort study was conducted in 32 consecutive AIS patients with and 51 without COVID-19 between the 1st of March 2020 and 1st of May 2021. The evaluation was based on a detailed chart review for demographic data, medical history, stroke severity, cranial and vessel imaging results, laboratory parameters, COVID-19 severity, hospitalization time, in-hospital mortality, and functional deficits at discharge (modified Rankin Scale, mRS). RESULTS: COVID-19 AIS patients showed tendency to worse initial neurological deficit (NIHSS 9 (3-13) vs. 4 (2-10); p = 0.06), higher rate of large vessel occlusion (LVO; 13/32 vs. 14/51; p = 0.21), had prolonged hospitalization (19.4 ± 17.7 vs. 9.7 ± 7 days; p = 0.003), had lower chance of functional independence (mRS≤2) (12/32 vs. 32/51; p = 0.02) and showed higher in-hospital mortality (10/32 vs. 6/51; p = 0.02). In COVID-19 AIS patients, LVO was more common with COVID-19 pneumonia than without (55.6% vs. 23.1%; p = 0.139). CONCLUSION: COVID-19-related AIS carries a worse prognosis. COVID-19 with pneumonia seems to be associated with a higher rate of LVO.

Improved Stroke Care in a Primary Stroke Centre Using AI-Decision Support.

BACKGROUND: Patient selection for reperfusion therapies requires significant expertise in neuroimaging. Increasingly, machine learning-based analysis is used for faster and standardized patient selection. However, there is little information on how such software influences real-world patient management. AIMS: We evaluated changes in thrombolysis and thrombectomy delivery following implementation of automated analysis at a high volume primary stroke centre. METHODS: We retrospectively collected data on consecutive stroke patients admitted to a large university stroke centre from two identical 7-month periods in 2017 and 2018 between which the e-Stroke Suite (Brainomix, Oxford, UK) was implemented to analyse non-contrast CT and CT angiography results. Delivery of stroke care was otherwise unchanged. Patients were transferred to a hub for thrombectomy. We collected the number of patients receiving intravenous thrombolysis and/or thrombectomy, the time to treatment; and outcome at 90 days for thrombectomy. RESULTS: 399 patients from 2017 and 398 from 2018 were included in the study. From 2017 to 2018, thrombolysis rates increased from 11.5% to 18.1% with a similar trend for thrombectomy (2.8-4.8%). There was a trend towards shorter door-to-needle times (44-42 min) and CT-to-groin puncture times (174-145 min). There was a non-significant trend towards improved outcomes with thrombectomy. Qualitatively, physician feedback suggested that e-Stroke Suite increased decision-making confidence and improved patient flow. CONCLUSIONS: Use of artificial intelligence decision support in a hyperacute stroke pathway facilitates decision-making and can improve rate and time of reperfusion therapies in a hub-and-spoke system of care.

Impact of COVID-19 on ischemic stroke care in Hungary.

Data about the coronavirus disease 2019 (COVID-19) pandemic's collateral damage on ischemic stroke (IS) care during the second epidemic wave in Central Europe are limited. We sought to evaluate the impact of the COVID-19 outbreak on Hungarian IS care during the two epidemic waves. This retrospective observational study was based on a nationwide reimbursement database that encompasses all IS admissions and all reperfusion interventions, i.e., intravenous thrombolysis (IVT) and endovascular therapy (EVT) from 2 January 2017 to 31 December 2020 in Hungary. COVID-19 pandemic's effect on the number of IS admissions and reperfusion interventions were analyzed using different statistics: means, medians, trends, relative rates, and linear relationships. The mean and median values of IS admissions and reperfusion interventions decreased only in some measure during the COVID-periods. However, trend analysis demonstrated a significant decline from the trends. The decline's dynamic and amplitude have differed for each variable. In contrast to IVT, the number of IS admissions and EVTs negatively correlated with the epidemic waves' amplitude. Besides, the decrease in the number of IS admissions was more pronounced than the decrease in the number of reperfusion interventions. Our study demonstrated a significant disruption in IS care during the COVID-19 epidemic in Hungary, in which multiple different factors might play a role. The disproportionate reduction of IS admission numbers could partially be explained by the effect of health emergency operative measures and changes in patients' social behavior. Further studies are needed to evaluate the causes of our observations.

Comparing extended versus standard time window for thrombectomy: caseload, patient characteristics, treatment rates and outcomes-a prospective single-centre study.

PURPOSE: New guidelines recommend thrombectomy up to 24 h in selected patients; however, the workload and benefit of extending time window are not known. We conducted a prospective single-centre study to determine the caseload, imaging and interventional need of extended time window. METHODS: All consecutive ischemic stroke patients within 24 h from onset in an 11-month period were included. Thrombectomy eligibility in the 0-6 h time window was based on current guidelines; in the 6-24 h time window, it was based on a combination of DEFUSE 3 and DAWN study criteria using MRI to identify target mismatch. Clinical outcome in treated patients was assessed at 3 months. RESULTS: Within 24 h of onset, 437 patients were admitted. In the 0-6 h time window, 238 patients (54.5%) arrived of whom 221 (92.9%) underwent CTA or MRA, 82 (34.5%) had large vessel occlusion (LVO), 30 (12.6%) had thrombectomy and 11 (36.6%) became independent (mRS ≤ 2). In the extended 6-24 h time window, 199 patients (45.5%) arrived of whom 127 (63.8%) underwent CTA or MRA, 44 (22.1%) had LVO, 8 (4%) had thrombectomy and 4 (50%) became independent. CONCLUSION: Extending the time window from 6 to 24 h results in a 26.7% increase in patients receiving thrombectomy and a 36.4% increase of independent clinical outcome in treated patients at the price of a significantly increased burden of clinical and imaging screening due to the similar caseload but a smaller proportion of treatment eligible patients in the extended as compared with the standard time window.

Effects of COVID-19 pandemic on acute ischemic stroke care. A single-centre retrospective analysis of medical collateral damage. / A COVID-19-pandémia hatása az akut ischaemiás stroke ellátásra. A járulékos egészségügyi veszteségek retrospektív, egycentrumos felmérése (A COVID-19-pandémia orvosszakmai kérdései).

INTRODUCTION: Early international observations report decreased number of acute ischemic stroke admissions and prolonged onset-to-treatment times during COVID-19 pandemic. AIM: Our goal was to assess the effect of COVID-19 pandemic on Hungarian acute ischemic stroke care. METHOD: We compared demographical and clinical characteristics, rate of intravenous and endovascular therapies and therapeutic time parameters of acute ischemic strokes admitted to a university stroke centre in a COVID-epidemic period (01/03/2020-30/04/2020) and an identical period of 2019. RESULTS: 86 patients were admitted during the COVID-period and 97 in the control period. Demographical and clinical characteristics of these periods were well-balanced. In the COVID-period, the proportion of patients arriving beyond 24 hours after onset increased by 13% (p = 0.046), the rate of endovascular interventions remained unchanged (8%), the rate of intravenous thrombolysis decreased from 26% to 16%, the mean onset-to-treatment time of thrombolysis increased by 20 minutes, while the mean door-to-treatment time increased by only 5 minutes. Behind the shift of arrival time categories, multivariable (year of examination, NIHSS, age) logistic regression shows that the year of examination might play a leading role (p = 0.096). CONCLUSION: In the COVID-period, admissions for acute ischemic strokes decreased by 11% and the proportion of cases certainly untreatable by reperfusion therapies (arriving beyond 24 hours after onset) increased significantly. While the rate of endovascular interventions remained unchanged, the absolute rate of intravenous thrombolysis decreased by 10% and the mean onset-to-treatment time showed a tendency to increase. In these changes, the COVID-epidemic itself and related out-of-hospital factors might play a leading role. Orv Hetil. 2020; 161(34): 1395-1399.

[Neurological aspects of the COVID-19 pandemic caused by the SARS-CoV-2 coronavirus]. / A SARS-CoV-2 koronavírus által okozott COVID-19-járvány neurológiai vonatkozásai.

By the spring of 2020 the COVID-19 outbreak caused by the new SARS-CoV-2 coronavirus has become a pandemic, requiring fast and efficient reaction from societies and health care systems all over the world. Fever, coughing and dyspnea are considered the major signs of COVID-19. In addition to the involvement of the respiratory system, the infection may result in other symptoms and signs as well. Based on reports to date, neurological signs or symptoms appear in 30-50% of hospitalized COVID-19 patients, with higher incidence in those with more severe disease. Classical acute neurological syndromes have also been reported to associate with COVID-19. A drop in the volume of services for other acute diseases has been described in countries with healthcare systems focusing on COVID-19. During the COVID-19 epidemic it is also important to provide appropriate continuous care for those with chronic neurological disorders. It will be the task of the future to estimate the collateral damage caused by the COVID-19 epidemic on the outcome of other neurological disorders, and to screen for the possible late neurological complications of the SARS-CoV-2 coronavirus infection.