Perioperative stroke

Diabetes Mellitus and Total Ankle Arthroplasty Complications

BACKGROUND

Postoperative infection, aseptic loosening, and perioperative medical complications after total ankle arthroplasty (TAA) are all devastating problems. While previous studies have shown diabetes as a risk factor predisposing patients to postoperative complications, not all literature supports this association following TAA. The goal of this study is to determine if diabetes influences midterm outcomes following TAA.

METHODS

An insurance database was utilized to identify patients undergoing TAA for ankle arthritis with a concurrent diagnosis of diabetes based on Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10), diagnosis and procedure codes from 2010 to 2021. The postoperative outcomes of all-cause revision, periprosthetic joint infection (PJI), septic revision, and aseptic revision were compared between patients with and without diabetes with a minimum 2-year follow-up using Kaplan-Meier and multivariate Cox proportional hazards analyses. Patient demographics, comorbidities, and Charlson Comorbidity Index were analyzed via univariate and multivariate analysis.

RESULTS

The study population included 8317 patients, 345 (4.1%) of whom had a concurrent diabetes diagnosis, who underwent TAA. After multivariate Cox proportional hazards analysis, the 5-year cumulative incidence of being coded as having PJI was 7.3% in patients with known diabetes compared to 3.9% in patients without known diabetes, with a 95% increased risk (hazard ratio [HR] 1.95, 95% CI 1.15-3.30, P = .01). Patients with diabetes also demonstrated a 5-year cumulative incidence of septic revision of 1.4% compared to 0.4% in those without, with a 363% increased risk (HR 4.63, 95% CI 1.22-17.52, P = .02). However, there was no difference in the 5-year cumulative incidence of all-cause revision TAA with 4.6% in patients with diabetes and 4.3% in those without (HR 1.29, 95% CI 0.69-2.44, P = .42).

CONCLUSION

In this database, the 5-year risk of PJI and septic revision was higher among patients with diabetes compared to those without, but cumulative incidence of all-cause revision TAA was not different between groups.

LEVEL OF EVIDENCE

Level III, retrospective cohort database study.

Pre-hospital stroke monitoring past, present, and future: a perspective

Integrated brain-machine interface signifies a transformative advancement in neurological monitoring and intervention modalities for events such as stroke, the leading cause of disability. Historically, stroke management relied on clinical evaluation and imaging. While today's stroke landscape integrates artificial intelligence for proactive clinical decision-making, mainly in imaging and stroke detection, it depends on clinical observation for early detection. Cardiovascular monitoring and detection systems, which have become standard throughout healthcare and wellness settings, provide a model for future cerebrovascular monitoring and detection. This commentary reviews the progression of continuous stroke monitoring, spotlighting contemporary innovations and prospective avenues, and emphasizes the influential roles of cutting-edge technologies in shaping stroke care.

Stroke after Cardiac Surgery: A Risk Factor Analysis of 580,117 Patients from UK National Adult Cardiac Surgical Audit Cohort

Cerebrovascular accident is the most ominous complication observed after cardiac surgery, carrying an increased risk of morbidity and mortality. Analysis of the problem shows its multidimensional nature. In this study, we aimed to identify major determinants among classic variables, either demographic, clinical or type of surgical procedure, based on the analysis of a large dataset of 580,117 patients from the UK National Adult Cardiac Surgical Audit (NACSA). For this purpose, univariate and multivariate logistic regression models were utilized to determine associations between predictors and dependent variable (Stroke after cardiac surgery). Odds ratios (ORs) and 95% confidence intervals (CIs) were constructed for each independent variable. Statistical analysis allows us to confirm with greater certainty the predictive value of some variables such as age, gender, diabetes mellitus (diabetes treated with insulin OR = 1.37, 95%CI = 1.23-1.53), and systemic arterial hypertension (OR = 1.11, 95%CI = 1.05-1.16);, to emphasize the role of preoperative atrial fibrillation (OR = 1.10, 95%CI = 1.03-1.16) extracardiac arteriopathy (OR = 1.70, 95%CI = 1.58-1.82), and previous cerebral vascular accident (OR 1.71, 95%CI = 1.6-1.9), and to reappraise others like smoking status (crude OR = 1.00, 95%CI = 0.93-1.07 for current smokers) or BMI (OR = 0.98, 95%CI = 0.97-0.98). This could allow for better preoperative risk stratification. In addition, identifying those surgical procedures (for example thoracic aortic surgery associated with a crude OR of 3.72 and 95%CI = 3.53-3.93) burdened by a high risk of neurological complications may help broaden the field of preventive and protective techniques.

Perioperative stroke

Ischaemic or haemorrhagic perioperative stroke (that is, stroke occurring during or within 30 days following surgery) can be a devastating complication following surgery. Incidence is reported in the 0.1-0.7% range in adults undergoing non-cardiac and non-neurological surgery, in the 1-5% range in patients undergoing cardiac surgery and in the 1-10% range following neurological surgery. However, higher rates have been reported when patients are actively assessed and in high-risk populations. Prognosis is significantly worse than stroke occurring in the community, with double the 30-day mortality, greater disability and diminished quality of life among survivors. Considering the annual volume of surgeries performed worldwide, perioperative stroke represents a substantial burden. Despite notable differences in aetiology, patient populations and clinical settings, existing clinical recommendations for perioperative stroke are extrapolated mainly from stroke in the community. Perioperative in-hospital stroke is unique with respect to the stroke occurring in other settings, and it is essential to apply evidence from other settings with caution and to identify existing knowledge gaps in order to effectively guide patient care and future research.

CD8+ T cells in brain injury and neurodegeneration

The interaction between the peripheral immune system and the brain is increasingly being recognized as an important layer of neuroimmune regulation and plays vital roles in brain homeostasis as well as neurological disorders. As an important population of T-cell lymphocytes, the roles of CD8+ T cells in infectious diseases and tumor immunity have been well established. Recently, increasing number of complex functions of CD8+ T cells in brain disorders have been revealed. However, an advanced summary and discussion of the functions and mechanisms of CD8+ T cells in brain injury and neurodegeneration are still lacking. Here, we described the differentiation and function of CD8+ T cells, reviewed the involvement of CD8+ T cells in the regulation of brain injury including stroke and traumatic brain injury and neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), and discussed therapeutic prospects and future study goals. Understanding these processes will promote the investigation of T-cell immunity in brain disorders and provide new intervention strategies for the treatment of brain injury and neurodegeneration.

Perioperative cortical hand stroke syndrome mimicking peripheral neuropathy: a case report

PURPOSE

Timely diagnosis of perioperative stroke is challenging, and therapeutic interventions are infrequently offered. The cortical hand syndrome is a rare stroke presentation that results from infarction of the precentral gyrus leading to variable neurologic deficits mimicking peripheral nerve injuries, with no prior reports in the perioperative setting. To raise awareness of this complication among anesthesiologists, we present a case of cortical hand syndrome in a surgical patient initially suspected to have a peripheral neuropathy.

CLINICAL FEATURES

A 68-yr-old male with multiple stroke risk factors underwent a nephroureterectomy under general anesthesia and thoracic epidural analgesia for urothelial carcinoma. The patient noted right-hand numbness and weakness to digits 3-5 immediately after surgery and notified his bedside nurse the following day. His symptoms were initially presumed to be a peripheral neuropathy secondary to surgical positioning. Computed tomography of the head the following day revealed an acute cortical infarct in the precentral gyrus consistent with cortical hand stroke syndrome. Subsequent neurologic consultation revealed additional subtle right-sided weakness. Further workup revealed moderate (60-80%) stenosis of the left carotid artery and he underwent a successful carotid endarterectomy one week later. His symptoms had mostly resolved six weeks later.

CONCLUSION

Cortical hand stroke syndrome is a rare presentation of perioperative stroke that may be misdiagnosed as a peripheral neuropathy. Our case presentation highlights that perioperative stroke should be considered for patients presenting with neurologic deficits of the hand, particularly those with deficits in multiple peripheral nerve territories and stroke risk factors.

MicroRNA-323-5p Involved in Dexmedetomidine Preconditioning Impart Neuroprotection

Background and Objectives: Cerebral ischemia is one of the major preoperative complications. Dexmedetomidine is a well-known sedative-hypnotic agent that has potential organ-protective effects. We examine the miRNAs associated with preconditioning effects of dexmedetomidine in cerebral ischemia. Materials and Methods: Transient infarcts were induced in mice via reperfusion after temporary occlusion of one side of the middle cerebral artery. A subset of these mice was exposed to dexmedetomidine prior to cerebral infarction and miRNA profiling of the whole brain was performed. We administered dexmedetomidine and miRNA-323-5p mimic/inhibitor to oxygen-glucose deprivation/reoxygenation astrocytes. Additionally, we administered miR-323-5p mimic and inhibitor to mice via intracerebroventricular injection 2 h prior to induction of middle cerebral artery occlusion. Results: The infarct volume was significantly lower in the dexmedetomidine-preconditioned mice. Analysis of brain samples revealed an increased expression of five miRNAs and decreased expression of three miRNAs in the dexmedetomidine-pretreated group. The viability of cells significantly increased and expression of miR-323-5p was attenuated in the dexmedetomidine-treated oxygen-glucose deprivation/reoxygenation groups. Transfection with anti-miR-323-5p contributed to increased astrocyte viability. When miRNA-323-5p was injected intraventricularly, infarct volume was significantly reduced when preconditioned with the miR-323-5p inhibitor compared with mimic and negative control. Conclusions: Dexmedetomidine has a protective effect against transient neuronal ischemia-reperfusion injury and eight specific miRNAs were profiled. Also, miRNA-323-5p downregulation has a cell protective effect under ischemic conditions both in vivo and in vitro. Our findings suggest the potential of the miR-323-5p inhibitor as a therapeutic agent against cerebral infarction.

Near-infrared spectroscopy and processed electroencephalogram monitoring for predicting peri-operative stroke risk in cardiothoracic surgery: An observational cohort study

BACKGROUND

Stroke is a feared complication after cardiothoracic surgery, with an incidence of around 2 to 3%. Anaesthesia and postoperative sedation may obscure clinical symptoms of stroke and thus delay diagnosis and timely intervention.

OBJECTIVES

The objective was to assess the value of intra-operative neuromonitoring and blood pressure monitoring for predicting the occurrence of peri-operative stroke within 3 days after cardiothoracic surgery.

DESIGN

Single-centre retrospective observational cohort study.

SETTING

Academic tertiary care medical centre.

PATIENTS

All consecutive patients with cardiothoracic surgery and intra-operative neuromonitoring admitted postoperatively to the Intensive Care Unit (ICU) between 2008 and 2017.

MAIN OUTCOME MEASURES

The primary endpoint was the occurrence of any stroke confirmed by brain imaging within 3 days postcardiothoracic surgery. Areas under the curve (AUC) of intra-operative mean arterial pressure (MAP), cerebral oxygen saturation (ScO2) and bispectral index (BIS) below predefined thresholds were calculated, and the association with early stroke was tested using logistic regression analyses.

RESULTS

A total of 2454 patients admitted to the ICU after cardiothoracic surgery had complete intra-operative data for ScO2, BIS and MAP and were included in the analysis. In 58 patients (2.4%), a stroke was confirmed. In univariate analysis, a larger AUCMAP greater than 60 mmHg [odds ratio (OR) 1.43; 95% confidence interval (CI), 1.21 to 1.68) and larger AUCBIS<25 (OR 1.51; 95% CI, 1.24 to 1.83) were associated with the occurrence of postoperative stroke while ScO2 less than 50% or greater than 20% reduction from individual baseline was not (OR 0.91; 95% CI, 0.50 to 1.67). After multivariable analysis, AUCBIS<25 (OR 1.45; 95% CI, 1.12 to 1.87) and longer duration of MAP less than 60 mmHg (OR 1.52; 95% CI, 1.02 to 2.27) remained independently associated with stroke occurrence.

CONCLUSION

Cumulative intra-operative BIS values below 25 and longer duration of MAP below 60 mmHg were associated with the occurrence of peri-operative stroke within 3 days after cardiothoracic surgery. Prospective studies are warranted to evaluate a causal relationship between low BIS and stroke to establish whether avoiding intra-operative BIS values below 25 might reduce the incidence of peri-operative stroke.

Importance of assessing biomarkers and physiological parameters of anemia-induced tissue hypoxia in the perioperative period

Anemia is associated with increased risk of Acute Kidney Injury (AKI), stroke and mortality in perioperative patients. We sought to understand the mechanism(s) by assessing the integrative physiological responses to anemia (kidney, brain), the degrees of anemia-induced tissue hypoxia, and associated biomarkers and physiological parameters. Experimental measurements demonstrate a linear relationship between blood Oxygen Content (C_aO₂) and renal microvascular PO₂ (y = 0.30x + 6.9, r² = 0.75), demonstrating that renal hypoxia is proportional to the degree of anemia. This defines the kidney as a potential oxygen sensor during anemia. Further evidence of renal oxygen sensing is demonstrated by proportional increase in serum Erythropoietin (EPO) during anemia (y = 93.806*10^-0.02, r² = 0.82). This data implicates systemic EPO levels as a biomarker of anemia-induced renal tissue hypoxia. By contrast, cerebral Oxygen Delivery (DO₂) is defended by a profound proportional increase in Cerebral Blood Flow (CBF), minimizing tissue hypoxia in the brain, until more severe levels of anemia occur. We hypothesize that the kidney experiences profound early anemia-induced tissue hypoxia which contributes to adaptive mechanisms to preserve cerebral perfusion. At severe levels of anemia, renal hypoxia intensifies, and cerebral hypoxia occurs, possibly contributing to the mechanism(s) of AKI and stroke when adaptive mechanisms to preserve organ perfusion are overwhelmed. Clinical methods to detect renal tissue hypoxia (an early warning signal) and cerebral hypoxia (a later consequence of severe anemia) may inform clinical practice and support the assessment of clinical biomarkers (i.e., EPO) and physiological parameters (i.e., urinary PO₂) of anemia-induced tissue hypoxia. This information may direct targeted treatment strategies to prevent adverse outcomes associated with anemia.

Myeloid-derived MIF drives RIPK1-mediated cerebromicrovascular endothelial cell death to exacerbate ischemic brain injury

Macrophage migration inhibitory factor (MIF) is a multifaced protein that plays important roles in multiple inflammatory conditions. However, the role of MIF in endothelial cell (EC) death under inflammatory condition remains largely unknown. Here we show that MIF actively promotes receptor-interacting protein kinase 1 (RIPK1)-mediated cell death under oxygen-glucose deprivation condition. MIF expression is induced by surgical trauma in peripheral myeloid cells both in perioperative humans and mice. We demonstrate that MIF-loaded myeloid cells induced by peripheral surgery adhere to the brain ECs after distal middle cerebral artery occlusion (dMCAO) and exacerbate the blood-brain barrier (BBB) disruption. Genetic depletion of myeloid-derived MIF in perioperative ischemic stroke (PIS) mice with MCAO following a surgical insult leads to significant reduction in ECs apoptosis and necroptosis and the associated BBB disruption. The adoptive transfer of peripheral blood mononuclear cells (PBMC) from surgical MIF^ΔLyz2 mice to wild-type (WT) MCAO mice also shows reduced ECs apoptosis and necroptosis compared to the transfer of PBMC from surgical MIF^{f  l/f  l} mice to MCAO recipients. The genetic inhibition of RIPK1 also attenuates BBB disruption and ECs death compared to that of WT mice in PIS. The administration of MIF inhibitor (ISO-1) and RIPK1 inhibitor (Nec-1s) can both reduce the brain EC death and neurological deficits following PIS. We conclude that myeloid-derived MIF promotes ECs apoptosis and necroptosis through RIPK1 kinase-dependent pathway. The above findings may provide insights into the mechanism as how peripheral inflammation promotes the pathology in central nervous system.

Impact of cerebrovascular accidents on lung transplant survival

BACKGROUND

Cerebrovascular accidents (CVA) are a source of postoperative morbidity. Existing data on CVA after lung transplantation (LT) are limited. We aimed to evaluate the impact of CVA on LT survival.

METHODS

A retrospective analysis of LT recipients at the University of Texas Southwestern Medical Center was performed. Data was obtained from the institutional thoracic transplant database between January 2012 and December 2018, which consisted of 476 patients. Patients were stratified by the presence of a postoperative CVA. Univariate comparisons of baseline characteristics, operative variables, and postoperative outcomes between the cohorts were performed. Survival was analyzed by Kaplan-Meier method. Aalen's additive regression model was utilized to assess mortality hazard over time.

RESULTS

The incidence of CVA was 4.2% (20/476). Lung allocation score was higher in the CVA cohort (46.2 [41.7, 57.3] vs. 41.5 [35.8, 52.2], p = 0.04). There were no significant differences in operative variables. CVA patients had longer initial intensive care unit (ICU) stays (316 h [251, 557] vs. 124 [85, 218], p < 0.001) and longer length of stay (22 days [17, 53] vs. 15 [11, 26], p = 0.007). CVA patients required more ICU readmissions (35% vs. 15%, p = 0.02) and had a lower rates of home discharge (35% vs. 71%, p < 0.001). Thirty-day mortality was higher in the CVA cohort (20% vs. 1.3%, p < 0.001). Overall survival was lower in the CVA cohort (log rank p = 0.044).

CONCLUSIONS

Postoperative CVA following LT was associated with longer ICU stays, more ICU readmissions, longer length of stay, and fewer home discharges. Thirty day and long-term mortality were significantly higher in the CVA group.

Preoperative risk model for perioperative stroke after intracranial tumor resection: ACS NSQIP analysis of 30,951 cases

OBJECTIVE

Perioperative and/or postoperative cerebrovascular accidents (PCVAs) after intracranial tumor resection (ITR) are serious complications with devastating effects on quality of life and survival. Here, the authors retrospectively analyzed a prospectively maintained, multicenter surgical registry to design a risk model for PCVA after ITR to support efforts in neurosurgical personalized medicine to risk stratify patients and potentially mitigate poor outcomes.

METHODS

The National Surgical Quality Improvement Program database was queried for ITR cases (2015-2019, n = 30,951). Patients with and without PCVAs were compared on baseline demographics, preoperative clinical characteristics, and outcomes. Frailty (physiological reserve for surgery) was measured by the Revised Risk Analysis Index (RAI-rev). Logistic regression analysis was performed to identify independent associations between preoperative covariates and PCVA occurrence. The ITR-PCVA risk model was generated based on logit effect sizes and assessed in area under the receiver operating characteristic curve (AUROC) analysis.

RESULTS

The rate of PCVA was 1.7% (n = 532). Patients with PCVAs, on average, were older and frailer, and had increased rates of nonelective surgery, interhospital transfer status, diabetes, hypertension, unintentional weight loss, and elevated BUN. PCVA was associated with higher rates of postoperative reintubation, infection, thromboembolic events, prolonged length of stay, readmission, reoperation, nonhome discharge destination, and 30-day mortality (all p < 0.001). In multivariable analysis, predictors of PCVAs included RAI "frail" category (OR 1.7, 95% CI 1.2-2.4; p = 0.006), Black (vs White) race (OR 1.5, 95% CI 1.1-2.1; p = 0.009), nonelective surgery (OR 1.4, 95% CI 1.1-1.7; p = 0.003), diabetes mellitus (OR 1.5, 95% CI 1.1-1.9; p = 0.002), hypertension (OR 1.4, 95% CI 1.1-1.7; p = 0.006), and preoperative elevated blood urea nitrogen (OR 1.4, 95% CI 1.1-1.8; p = 0.014). The ITR-PCVA predictive model was proposed from the resultant multivariable analysis and performed with a modest C-statistic in AUROC analysis of 0.64 (95% CI 0.61-0.66). Multicollinearity diagnostics did not detect any correlation between RAI-rev parameters and other covariates (variance inflation factor = 1).

CONCLUSIONS

The current study proposes a novel preoperative risk model for PCVA in patients undergoing ITR. Patients with poor physiological reserve (measured by frailty), multiple comorbidities, abnormal preoperative laboratory values, and those admitted under high acuity were at highest risk. The ITR-PCVA risk model may support patient-centered counseling striving to respect goals of care and maximize quality of life. Future prospective studies are warranted to validate the ITR-PCVA risk model and evaluate its utility as a bedside clinical tool.

Pre-operative anemia was associated with all-cause mortality in patients with vertebral fracture who underwent percutaneous vertebroplasty

PURPOSE

We investigated the association between pre-operative anemia and long-term all-cause mortality in patients with vertebral fracture who underwent a vertebroplasty.

MATERIALS AND METHODS

We retrospectively selected patients who were admitted for vertebroplasty for vertebral compression fracture between 2013 and 2020. Patients who had pathologic fractures or had no assessment of bone mineral density were excluded. Relevant information was collected from electronic medical records. Patients' survival status was confirmed at the end of March 2021. Cox-proportional hazard models were conducted to examine the effects of anemia (<12 g/dL vs. ≥12 g/dL) and pre-operative hemoglobin levels (as a continuous variable) on all-cause mortality with multivariate adjustments.

RESULTS

A total of 167 patients were analyzed (mean age 75.8 ± 9.3 years, male 25.7%). After a median follow-up duration of 2.1 years, pre-operative anemia (hemoglobin <12 g/dL vs. ≥12 g/dL) was independently associated with a higher risk of all-cause mortality (hazard ratio 2.762, 95% CI 1.184 to 6.442, p = 0.019). An increase in pre-operative hemoglobin was associated with a lower risk of all-cause mortality after multivariate adjustment (hazard ratio 0.775, 95% CI 0.606 to 0.991, p = 0.042).

CONCLUSION

Pre-operative anemia (<12 g/dL) was independently associated with survival outcome among patients with vertebral compression fractures who underwent vertebroplasty. Our findings highlight anemia as a risk factor of long-term mortality in this elderly surgical population.

Hypertriglyceridemia is associated with stroke after non-cardiac, non-neurological surgery in the older patients: A nested case-control study

Introduction

Geriatric postoperative stroke is a rare but serious complication after surgery. The association between hypertriglyceridemia and postoperative stroke remains controversial, especially in older patients undergoing non-cardiac, non-neurological surgery. The study aims to address this clinical dilemma.

Materials and methods

We conducted a nested case-control study among 9601 aged patients undergoing non-cardiac non-neurological surgery from October 2015 to 2021. A total of 22 positive cases were matched for the surgical type and time, to 88 control patients by a ratio of 1:4. The effect of hypertriglyceridemia on the occurrence of postoperative stroke within 30 days after surgery was estimated using conditional logistic regression analysis by adjusting to various potential confounders.

Results

A total of 22 cases developed ischemia stroke after surgery, and compared with the non-stroke group, they had more postoperative ICU admission, longer postoperative hospitalization and higher total cost (all p &lt; 0.05), and more patients were presenting with preoperative hypertriglyceridemia [8 (36.4%) vs. 15 (17.0%), p = 0.045]. There was a significant association between hypertriglyceridemia and postoperative stroke, with adjusted odds ratios of 6.618 (95% CI 1.286, 34.064) (p = 0.024). The above results remained robust in the sensitivity analyses.

Conclusion

Among older patients undergoing non-cardiac and non-neurological surgery, hypertriglyceridemia was associated with significant increased risk of postoperative stroke.

The potential link between obstructive sleep apnea and postoperative neurocognitive disorders: current knowledge and possible mechanisms

PURPOSE

This narrative review examines the current evidence on whether obstructive sleep apnea (OSA) is associated with postoperative delirium (POD) and postoperative cognitive dysfunction (POCD). The mechanisms that could predispose OSA patients to these disorders are also explored.

SOURCE

Relevant literature was identified by searching for pertinent terms in Medline®, Pubmed, ScopusTM, and Google scholar databases. Case reports, abstracts, review articles, original research articles, and meta-analyses were reviewed. The bibliographies of retrieved sources were also searched to identify relevant papers.

PRINCIPAL FINDINGS

Seven studies have investigated the association between OSA and POD, with mixed results. No studies have examined the potential link between OSA and POCD. If these relationships exist, they could be mediated by several mechanisms, including increased neuroinflammation, blood-brain barrier breakdown, cerebrovascular disease, Alzheimer's disease neuropathology, disrupted cerebral autoregulation, sleep disruption, sympathovagal imbalance, and/or disrupted brain bioenergetics.

CONCLUSION

There is very limited evidence that OSA plays a role in postoperative neurocognitive disorders because few studies have been conducted in the perioperative setting. Additional perioperative prospective observational cohort studies and randomized controlled trials of sleep apnea treatment are needed. These investigations should also assess potential underlying mechanisms that could predispose patients with OSA to postoperative neurocognitive disorders. This review highlights the need for more research to improve postoperative neurocognitive outcomes for patients with OSA.

A review of perioperative anemia: A modifiable and not so benign risk factor

Anemia is a commonly encountered finding either during the preoperative assessment or during the postoperative management of the patient. Anemia often gets overlooked while more emphasis is paid to cardiovascular and pulmonary evaluation. Evidence, however, suggests that the presence of anemia in the perioperative period can predispose patients to other complications. Awareness of the consequences of anemia in the perioperative period can lead to better recognition and early management of this potentially modifiable risk factor. In this review, we focus on the effects of anemia on the cardiac, pulmonary, neurologic, cognitive, and functional status outcomes of patients. We also review management strategies that could be employed, depending on the available time and resources.

Analysis of the Surgical Outcomes in Elderly Patients with Hip Fractures Combined with Hemiplegia

Objective

This study aimed to investigate the surgical outcomes in elderly (age ≥65) patients with hip fractures combined with hemiplegia and compare them with the surgical outcomes in elderly patients with hip fractures but no hemiplegia.

Methods

A total of 761 elderly patients with hip fractures who were treated between January 2013 and December 2019 were enrolled in this study using a retrospective study design. The patients were divided into two groups: a hemiplegia group (77 cases, 10.1%) and a non-hemiplegia group (684 cases, 89.9%). Length of hospital stay, postoperative complications, 30-day and one-year mortalities, and one-year functional status were compared between the two groups.

Results

The average length of hospital stay in the hemiplegia group (13.51 ± 10.17 days) was longer than in the non-hemiplegia group (12.60 ± 7.83 days), but the difference was not statistically significant (P = 0.354). The incidence of postoperative complications in patients with hemiplegia (28.6%, 22/77) was higher than in patients without hemiplegia (15.4%, 105/684), and the difference was statistically significant (P = 0.003). The 30-day and one-year mortalities in the hemiplegia group were higher than in the non-hemiplegia group (30 days after surgery: 10.4%, 8/77 vs 4.5%, 31/684; one year after surgery: 29.9%, 23/77 vs 15.2%, 104/684), and the difference was statistically significant (30 days after surgery: P = 0.027; one year after surgery: P = 0.001). One year after surgery, the average activity of daily living score was 56.02 ± 9.63 in the hemiplegia group and 76.89 ± 8.40 in the non-hemiplegia group, and the difference was statistically significant (P = 0.000).

Conclusion

Hemiplegia can increase the incidence of postoperative complications and 30-day and one-year mortalities in patients with hip fractures.

The immunometabolite S-2-hydroxyglutarate exacerbates perioperative ischemic brain injury and cognitive dysfunction by enhancing CD8+ T lymphocyte-mediated neurotoxicity

Background

Metabolic dysregulation and disruption of immune homeostasis have been widely associated with perioperative complications including perioperative ischemic stroke. Although immunometabolite S-2-hydroxyglutarate (S-2HG) is an emerging regulator of immune cells and thus triggers the immune response, it is unclear whether and how S-2HG elicits perioperative ischemic brain injury and exacerbates post-stroke cognitive dysfunction.

Methods

Perioperative ischemic stroke was induced by transient middle cerebral artery occlusion for 60 min in C57BL/6 mice 1 day after ileocecal resection. CD8⁺ T lymphocyte activation and invasion of the cerebrovascular compartment were measured using flow cytometry. Untargeted metabolomic profiling was performed to detect metabolic changes in sorted CD8⁺ T lymphocytes after ischemia. CD8⁺ T lymphocytes were transfected with lentivirus ex vivo to mobilize cell proliferation and differentiation before being transferred into recombination activating gene 1 (Rag1^−/−) stroke mice.

Results

The perioperative stroke mice exhibit more severe cerebral ischemic injury and neurological dysfunction than the stroke-only mice. CD8⁺ T lymphocyte invasion of brain parenchyma and neurotoxicity augment cerebral ischemic injury in the perioperative stroke mice. CD8⁺ T lymphocyte depletion reverses exacerbated immune-mediated cerebral ischemic brain injury in perioperative stroke mice. Perioperative ischemic stroke triggers aberrant metabolic alterations in peripheral CD8⁺ T cells, in which S-2HG is more abundant. S-2HG alters CD8⁺ T lymphocyte proliferation and differentiation ex vivo and modulates the immune-mediated ischemic brain injury and post-stroke cognitive dysfunction by enhancing CD8⁺ T lymphocyte-mediated neurotoxicity.

Conclusion

Our study establishes that S-2HG signaling-mediated activation and neurotoxicity of CD8⁺ T lymphocytes might exacerbate perioperative ischemic brain injury and may represent a promising immunotherapy target in perioperative ischemic stroke.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02537-4.

Femoral and Lateral Femoral Cutaneous Nerve Block as Anesthesia for High-Risk Intertrochanteric Fracture Repair Patients

Introduction. Intertrochanteric fracture (IF) is a common injury among the elderly. Due to significant comorbidities, anesthesia for IF repair may be challenging. The authors propose femoral nerve block together with a lateral femoral cutaneous nerve block and sedation as an anesthetic technique for most severe cases of IF with contraindications to spinal anesthesia. Methods. In total, 61 patients were enrolled prospectively in a study, 19 received general anesthesia (GA group), 22 spinal anesthesia (SA group), and 20 nerve blocks with sedation (PNB group). Results. Groups were comparable in terms of age, gender, independence, and several comorbidities: diabetes, obesity, underweight, cardiovascular, and cerebrovascular incidents in the past, dementia, chronic obstructive pulmonary disease, and frailty. Heart failure (p = 0.033), hemoglobin < 10 g/dL (p = 0.001) and eGFR < 30 mL/min (p = 0.039) were more frequent in PNB group. PNB group had higher American Society of Anesthesiologists (ASA) (p < 0.001), Nottingham Hip Fracture Score (NHFS) (p < 0.001), and Charlson Comorbidity Index (CCI) (p = 0.002) scales scores, and lower probability of 10-year survival according to CCI (p = 0.012). GA group had more frequent active malignancy (p = 0.041). GA and PNB groups had a higher frequency of hemostasis disorder (p < 0.001). Surgery was completed under the scheduled anesthesia technique. Survival, frequency of cardio and cerebrovascular incidents after surgery, loss of independence, and postoperative delirium were comparable between groups, as well as the length of postoperative stay. Conclusions. Surgical repair of intertrochanteric fracture with intramedullary nailing system among elderly, frail, and sick patients can be conducted under peripheral nerve block. FNB and LFCNB in the combination is a viable option for IT fracture repair.

Type 2 Diabetes Increases Risk of Unfavorable Survival Outcome for Postoperative Ischemic Stroke in Patients Who Underwent Non-cardiac Surgery: A Retrospective Cohort Study

Objective: Diabetes mellitus (DM) has been critically associated with unfavorable outcomes in the general population. We aimed to investigate the association between type 2 DM and long-term survival outcomes for postoperative ischemic stroke in patients who underwent non-cardiac surgery. Research Design and Methods: This was a retrospective cohort study of patients with non-cardiac surgery who had suffered from postoperative ischemic stroke between January 2008 and August 2019. Diabetic individuals were included in postoperative ischemic stroke patients with the DM group. The outcome of interest was long-term overall survival (OS). We conducted propensity score matching (PSM) and inverse probability treatment weighting (IPTW) to adjust for baseline characteristic differences between groups. Multivariate Cox regression analysis with stepwise selection was used to calculate the adjusted hazard ratio (HR) of OS and type 2 DM. Results: During a median follow-up of 46.2 month [interquartile range (IQR), 21.1, 84.2], 200 of 408 patients (49.0%) died. The OS rates at 3, 5, and 10 years were significantly lower for postoperative ischemic stroke patients with DM than those without DM (3 years OS: 52.2 vs. 69.5%, p < 0.001; 5 years OS: 41.6 vs. 62.4%, p < 0.001; 10 years OS: 37.2 vs. 56.6%, p < 0.001). All covariates were between-group balanced after using PSM or IPTW. The postoperative ischemic stroke patients with type 2 DM had a shortened OS in primary analysis (HR: 1.947; 95% CI: 1.397-2.713; p < 0.001), PSM analysis (HR: 2.190; 95% CI: 1.354-3.540; p = 0.001), and IPTW analysis (HR: 2.551; 95% CI: 1.769-3.679; p < 0.001). Conclusion: Type 2 DM was associated with an unfavorable survival outcome for postoperative ischemic stroke in patients who underwent non-cardiac surgery. When postoperative ischemic stroke co-occurred with type 2 DM, the potential synergies would have multiplicative mortality risk. Further research to assess the adverse effects of type 2 DM on long-term survival may be warranted.

Cause-Specific Mortality as a Sequalae of Perioperative Stroke Following Cardiac and Vascular Surgery

BACKGROUND

There is a paucity of data regarding cause-specific mortality following a perioperative stroke. In this study, we aim to establish the risk of cause-specific mortality associated with perioperative stroke following cardiac and vascular procedures at 30 days, 90 days, and 1-year postoperative. It is hoped that this fund of knowledge will enhance perioperative risk stratification and medical management for patients who have suffered a perioperative stroke.

METHODS

This is a retrospective cohort study evaluating 277,654 cardiac and vascular surgical patients dually documented within the Inpatient Discharge Claims Database and the Pennsylvania Department of Health Death Statistics database. A univariate assessment followed by a multivariate logistic regression analysis was used to determine the odds of cerebrovascular, cardiovascular, pulmonary, malignancy, infectious, and dementia causes of mortality following perioperative stroke.

RESULTS

Perioperative stroke significantly increased the odds of overall mortality (P<0.0001) as well as cause-specific mortality in all categories (P<0.05) except dementia (P=0.8907) at all-time endpoints. Cerebrovascular-related mortality was most impacted by perioperative stroke [adjusted odds ratio: 34.5 (29.1, 40.9), P<0.0001 at 30 d].

CONCLUSIONS

Perioperative stroke in the cardiac and vascular surgical population is associated with increased odds of overall, cerebrovascular, cardiovascular, pulmonary, malignancy, and infectious causes of mortality at 30 days, 90 days, and 1-year postoperatively when compared with patients who did not experience a perioperative stroke.

Combining CHA2DS2-VASc score into RCRI for prediction perioperative cardiovascular outcomes in patients undergoing non-cardiac surgery: a retrospective pilot study

Background

Treatment decisions in patients undergoing non-cardiac surgery are based on clinical assessment. The Revised Cardiac Risk Index (RCRI) is pragmatic and widely used but has only moderate discrimination. We aimed to test the efficacy of the CHA₂DS₂-VASc score and the combination of CHA₂DS₂-VASc and RCRI to predict perioperative risks for non-cardiac surgery.

Methods

This pre-specified analysis was performed in a retrospective cohort undergoing intra-abdominal surgery in our center from July 1st, 2007 to June 30th, 2008. The possible association between the baseline characteristics (as defined by CHA₂DS₂-VASc and RCRI) and the primary outcome of composite perioperative cardiac complications (myocardial infarction, cardiac ischemia, heart failure, arrhythmia, stroke, and/or death) and secondary outcomes of individual endpoints were explored using multivariate Logistic regression. The area under the receiver operating characteristic curve (C-statistic) was used for RCRI, CHA₂DS₂-VASc, and the combined models, and the net reclassification improvement (NRI) was calculated to assess the additional discriminative ability.

Results

Of the 1079 patients (age 57.5 ± 17.0 years), 460 (42.6%) were women. A total of 83 patients (7.7%) reached the primary endpoint. Secondary outcomes included 52 cardiac ischemic events, 40 myocardial infarction, 20 atrial fibrillation, 18 heart failure, four strokes, and 30 deaths. The endpoint events increased with the RCRI and CHA₂DS₂-VASc grade elevated (P < 0.05 for trend). The RCRI showed a moderate predictive ability with a C-statistics of 0.668 (95%CI 0.610–0.725) for the composite cardiac outcome. The C-statistics for the CHA₂DS₂-VASc was 0.765 (95% CI 0.709–0.820), indicating better performance than the RCRI (p = 0.011). Adding the CHA₂DS₂-VASc to the RCRI further increased the C-statistic to 0.774(95%CI 0.719–0.829), improved sensitivity, negative predictive value, and enhanced reclassification in reference to RCRI. Similar performance of the combined scores was demonstrated in the analysis of individual secondary endpoints. The best cut-off of a total of 4 scores was suggested for the combined CHA₂DS₂-VASc and RCRI in the prediction of the perioperative cardiac outcomes.

Conclusions

The CHA₂DS₂-VASc score significantly enhanced risk assessment for the composite perioperative cardiovascular outcome in comparison to traditional RCRI risk stratification. Incorporation of CHA₂DS₂-VASc scores into clinical-decision making to improve perioperative management in patients undergoing non-cardiac surgery warrants consideration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01496-2.

A Novel Thromboplastin-Based Rat Model of Ischemic Stroke

The thromboembolic ischemia model is one of the most applicable for studying ischemic stroke in humans. The aim of this study was to develop a novel thromboembolic stroke model, allowing, by affordable tools, to reproduce cerebral infarction in rats. In the experimental group, the left common carotid artery, external carotid artery, and pterygopalatine branch of maxillary artery were ligated. A blood clot that was previously formed (during a 20 min period, in a catheter and syringe, by mixing with a thromboplastin solution and CaCl₂) was injected into the left internal carotid artery. After 10 min, the catheter was removed, and the incision was sutured. The neurological status of the animals was evaluated using a 20-point scale. Histological examination of brain tissue was performed 6, 24, 72 h, and 6 days post-stroke. All groups showed motor and behavioral disturbances 24 h after surgery, which persisted throughout the study period. A histological examination revealed necrotic foci of varying severity in the cortex and subcortical regions of the ipsilateral hemisphere, for all experimental groups. A decrease in the density of hippocampal pyramidal neurons was revealed. Compared with existing models, the proposed ischemic stroke model significantly reduces surgical time, does not require an expensive operating microscope, and consistently reproduces brain infarction in the area of the middle cerebral artery supply.

Long noncoding RNA Meg3 mediates ferroptosis induced by oxygen and glucose deprivation combined with hyperglycemia in rat brain microvascular endothelial cells, through modulating the p53/GPX4 axis

Individuals with diabetes are exposed to a higher risk of perioperative stroke than non-diabetics mainly due to persistent hyperglycemia. LncRNA Meg3 has been considered as an important mediator in regulating ischemic stroke. However, the functional and regulatory roles of Meg3 in diabetic brain ischemic injury remain unclear. In this study, rat brain microvascular endothelial cells (RBMVECs) were exposed to 6 h of oxygen and glucose deprivation (OGD), and subsequent reperfusion via incubating cells with glucose of various high concentrations for 24 h to imitate in vitro diabetic brain ischemic injury. It was shown that the marker events of ferroptosis and increased Meg3 expression occurred after the injury induced by OGD combined with hyperglycemia. However, all ferroptotic events were reversed with the treatment of Meg3-siRNA. Moreover, in this in vitro model, p53 was also characterized as a downstream target of Meg3. Furthermore, p53 knockdown protected RBMVECs against OGD + hyperglycemic reperfusion-induced ferroptosis, while the overexpression of p53 exerted opposite effects, implying that p53 served as a positive regulator of ferroptosis. Additionally, the overexpression or knockdown of p53 significantly modulated GPX4 expression in RBMVECs exposed to the injury induced by OGD combined with hyperglycemic treatment. Furthermore, GPX4 expression was suppressed again after the reintroduction of p53 into cells silenced by Meg3. Finally, chromatin immunoprecipitation assay uncovered that p53 was bound to GPX4 promoter. Altogether, these data revealed that, by modulating GPX4 transcription and expression, the Meg3-p53 signaling pathway mediated the ferroptosis of RBMVECs upon injury induced by OGD combined with hyperglycemic reperfusion.

Development and external validation of a prognostic model for ischaemic stroke after surgery

BACKGROUND

There is an under-recognised patient cohort at elevated risk of postoperative ischaemic stroke. We aimed to develop and validate a prognostic model for the identification of such patients at high risk of ischaemic stroke within 1 yr after noncardiac surgery.

METHODS

This was a hospital registry study of adult patients undergoing noncardiac surgery between 2005 and 2017 at two independent healthcare networks in Massachusetts, USA without a preoperative indication for therapeutic anticoagulation. Logistic regression was used to fit a model from a priori defined candidate predictors for the outcome 1 yr postoperative ischaemic stroke. To enhance clinical applicability, the model was simplified to a scoring system and externally validated.

RESULTS

In the development (n=107 756) and validation (n=141 724) cohorts, 1.4% and 0.5% of patients had an ischaemic stroke up to 1 yr postoperatively. The final model included 13 variables (patient characteristics, comorbidities, procedural factors), considering sub-models conditional on a previous history of ischaemic stroke. Areas under the curve were 0.89 (95% confidence interval 0.89-0.90) and 0.88 (95% confidence interval 0.86-0.89) in the development and validation cohorts. Decision curve analysis indicated positive net benefits superior to other prediction instruments.

CONCLUSIONS

Stroke after surgery (STRAS) screening can reliably identify patients with a high risk for ischaemic stroke during the first year after surgery. A STRAS-guided risk stratification may inform the recruitment to future randomised trials testing the efficacy of treatments for the prevention of postoperative ischaemic stroke.

Risk of cardiovascular complications during non-cardiac surgery and preoperative cardiac evaluation

The preoperative evaluation of candidates to non-cardiac surgery requires a knowledge of factors related both to the type of surgery and to the risk of each patient, in order to predict the potential cardiovascular complications. Over the past several decades, the field of preoperative cardiac evaluation before non-cardiac surgery has evolved substantially on the basis of the current guidelines of international medical societies. The aim of this paper is to summarize available evidence on the risk of non-cardiac surgery, focusing on appropriate cardiovascular assessment prior to surgery.

Perioperative massive cerebral stroke in thoracic patients: Report of three cases

BACKGROUND

Perioperative stroke is a rare but devastating complication. The risk factors for massive cerebral stroke in surgical patients include older age, male sex, prior cerebrovascular disease, hypertension, renal failure, smoking, diabetes mellitus, and atrial fibrillation.

CASE SUMMARY

We describe two cases of perioperative massive cerebral stroke following thoracic surgery and one case following bronchoscopy. Neurologic symptoms, including changes in mental status and hemiplegia, occurred within 10 h after surgery in the three patients. All three patients died after the surgery.

CONCLUSION

Perioperative massive cerebral stroke may be more likely to occur in thoracic surgical patients if there are pre-existing factors including previous stroke, hypotension, and hypoxemia. Sufficient pain control after surgery and timely neurology consultation and management are helpful for the diagnosis and control of stroke in high-risk patients.

Predictive Factors of Perioperative Stroke-Related Mortality Following Vascular Surgery: A Retrospective Analysis

OBJECTIVE

Vascular surgical procedures have one of the highest risks of perioperative stroke and stroke-related mortality, yet the independent risk factors contributing to this increased mortality have not been described. Perioperative strokes are thought to result from a combination of embolism and hypoperfusion mechanisms. The purpose of this study is to describe the independent predictors of perioperative stroke-related mortality in the vascular surgical population using the Pennsylvania Health Care Cost Containment Council (PHC4) database which collects cause of death data.

METHODS

This retrospective, case-control study evaluated 4,128 patients aged 18-99 who underwent a vascular, non-carotid surgical procedure and subsequently suffered perioperative mortality. Common surgical comorbidities and risk factors for perioperative stroke, including carotid stenosis and atrial fibrillation, were evaluated in multivariate regression analysis.

RESULTS

Patients with carotid stenosis were 2.6 (aOR, 95% CI 1.4-4.5) times more likely to suffer perioperative mortality from stroke than from other causes. Additionally, in-hospital stroke, history of stroke, admission from a healthcare facility, and cancer were all positive predictive factors, whereas atrial fibrillation, emergency admission, hypertension, and diabetes were associated with decreased risk of perioperative stroke-related mortality.

CONCLUSIONS

Identification of vascular surgical population-specific predictors of stroke-related mortality can help to enhance preoperative risk-stratification tools and guide perioperative management of identified high-risk patients. Increased neurophysiologic monitoring in the perioperative period to prevent delays in diagnosis of perioperative stroke offers a strategy to reduce risk of perioperative stroke-related mortality in vascular surgical patients.

Mechanisms of thrombosis and research progress on targeted antithrombotic drugs

Globally, the incidence of thromboembolic diseases has increased in recent years, accompanied by an increase in patient mortality. Currently, several targeting delivery strategies have been developed to treat thromboembolic diseases. In this review, we discuss the mechanisms of thrombolysis and current anticoagulant drugs, particularly those with targeting capability, highlighting advances in the accurate treatment of thrombolysis with fewer adverse effects. Such approaches include magnetic drug-loading systems combined with molecular imaging to recanalize blood vessels and systems based on chimeric Arg-Gly-Asp (RGD) sequences that can target platelet glycoprotein receptor. With such progress in targeted antithrombotic drugs, targeted thrombolysis treatment shows significant potential benefit for patients.

Perioperative Neurological Evaluation and Management to Lower the Risk of Acute Stroke in Patients Undergoing Noncardiac, Nonneurological Surgery: A Scientific Statement From the American Heart Association/American Stroke Association

Perioperative stroke is a potentially devastating complication in patients undergoing noncardiac, nonneurological surgery. This scientific statement summarizes established risk factors for perioperative stroke, preoperative and intraoperative strategies to mitigate the risk of stroke, suggestions for postoperative assessments, and treatment approaches for minimizing permanent neurological dysfunction in patients who experience a perioperative stroke. The first section focuses on preoperative optimization, including the role of preoperative carotid revascularization in patients with high-grade carotid stenosis and delaying surgery in patients with recent strokes. The second section reviews intraoperative strategies to reduce the risk of stroke, focusing on blood pressure control, perioperative goal-directed therapy, blood transfusion, and anesthetic technique. Finally, this statement presents strategies for the evaluation and treatment of patients with suspected postoperative strokes and, in particular, highlights the value of rapid recognition of strokes and the early use of intravenous thrombolysis and mechanical embolectomy in appropriate patients.

Effects of Volatile Anesthetics on Postoperative Ischemic Stroke Incidence

Background

Preclinical studies suggest that volatile anesthetics decrease infarct volume and improve the outcome of ischemic stroke. This study aims to determine their effect during noncardiac surgery on postoperative ischemic stroke incidence.

Methods and Results

This was a retrospective cohort study of surgical patients undergoing general anesthesia at 2 tertiary care centers in Boston, MA, between October 2005 and September 2017. Exclusion criteria comprised brain death, age <18 years, cardiac surgery, and missing covariate data. The exposure was defined as median age‐adjusted minimum alveolar concentration of all intraoperative measurements of desflurane, sevoflurane, and isoflurane. The primary outcome was postoperative ischemic stroke within 30 days. Among 314 932 patients, 1957 (0.6%) experienced the primary outcome. Higher doses of volatile anesthetics had a protective effect on postoperative ischemic stroke incidence (adjusted odds ratio per 1 minimum alveolar concentration increase 0.49, 95% CI, 0.40–0.59, P<0.001). In Cox proportional hazards regression, the effect was observed for 17 postoperative days (postoperative day 1: hazard ratio (HR), 0.56; 95% CI, 0.48–0.65; versus day 17: HR, 0.85; 95% CI, 0.74–0.99). Volatile anesthetics were also associated with lower stroke severity: Every 1‐unit increase in minimum alveolar concentration was associated with a 0.006‐unit decrease in the National Institutes of Health Stroke Scale (95% CI, −0.01 to −0.002, P=0.002). The effects were robust throughout various sensitivity analyses including adjustment for anesthesia providers as random effect.

Conclusions

Among patients undergoing noncardiac surgery, volatile anesthetics showed a dose‐dependent protective effect on the incidence and severity of early postoperative ischemic stroke.

Immunomodulatory lipid mediator profiling of cerebrospinal fluid following surgery in older adults

Arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) derived lipids play key roles in initiating and resolving inflammation. Neuro-inflammation is thought to play a causal role in perioperative neurocognitive disorders, yet the role of these lipids in the human central nervous system in such disorders is unclear. Here we used liquid chromatography–mass spectrometry to quantify AA, DHA, and EPA derived lipid levels in non-centrifuged cerebrospinal fluid (CSF), centrifuged CSF pellets, and centrifuged CSF supernatants of older adults obtained before, 24 h and 6 weeks after surgery. GAGE analysis was used to determine AA, DHA and EPA metabolite pathway changes over time. Lipid mediators derived from AA, DHA and EPA were detected in all sample types. Postoperative lipid mediator changes were not significant in non-centrifuged CSF (p > 0.05 for all three pathways). The AA metabolite pathway showed significant changes in centrifuged CSF pellets and supernatants from before to 24 h after surgery (p = 0.0000247, p = 0.0155 respectively), from before to 6 weeks after surgery (p = 0.0000497, p = 0.0155, respectively), and from 24 h to 6 weeks after surgery (p = 0.0000499, p = 0.00363, respectively). These findings indicate that AA, DHA, and EPA derived lipids are detectable in human CSF, and the AA metabolite pathway shows postoperative changes in centrifuged CSF pellets and supernatants.

Cardiovascular events in patients undergoing hip fracture surgery treated with remote ischaemic preconditioning: 1-year follow-up of a randomised clinical trial

Remote ischaemic preconditioning reduces the risk of myocardial injury within 4 days of hip fracture surgery. We aimed to investigate the effect of remote ischaemic preconditioning on the incidence of major adverse cardiovascular events 1 year after hip fracture surgery. We performed a phase-2, multicentre, randomised, observer-blinded, clinical trial between February 2015 and September 2017. We studied patients aged ≥ 45 years with a hip fracture and a minimum of one cardiovascular risk factor. Patients were allocated randomly to remote ischaemic preconditioning applied just before surgery or no treatment (control group). Remote ischaemic preconditioning was performed on the upper arm with a tourniquet in four cycles of 5 min ischaemia and 5 min reperfusion. Primary outcome was the occurrence of major adverse cardiovascular events within 1 year of surgery. A total of 316 patients were allocated randomly to the remote ischaemic preconditioning group and 309 patients to the control group. Major adverse cardiovascular events occurred in 43 patients (13.6%) in the remote ischaemic preconditioning group compared with 51 patients (16.5%) in the control group (adjusted hazard ratio (95%CI) 0.83 (0.55-1.25); p = 0.37). Fewer patients in the remote ischaemic preconditioning group had a myocardial infarction (11 (3.5%) vs. 22 (7.1%); hazard ratio (95%CI) 0.48 (CI 0.23-1.00); p = 0.04). Remote ischaemic preconditioning did not reduce the occurrence of major adverse cardiovascular events within 1 year of hip fracture surgery. The effect of remote ischaemic preconditioning on clinical cardiovascular outcomes in non-cardiac surgery needs confirmation in appropriately powered randomised clinical trials.

Anesthesia for Combined Heart and Liver Transplantation

A heart or liver transplantation procedure performed in isolation itself presents multiple challenges for the perioperative team. Accordingly, combining both transplants yields a vastly more complicated surgery, with many unique multisystem and multidisciplinary considerations. Although combined heart and liver transplantations are being performed with increasing frequency, nationwide experience is relatively limited at most institutions. The aim of this review is to discuss the perioperative challenges presented to the anesthesiology teams and provide evidence-based guidance for the management of these daunting procedures.

Neuroimaging and deep learning for brain stroke detection - A review of recent advancements and future prospects

BACKGROUND AND OBJECTIVE

In recent years, deep learning algorithms have created a massive impact on addressing research challenges in different domains. The medical field also greatly benefits from the use of improving deep learning models which save time and produce accurate results. This research aims to emphasize the impact of deep learning models in brain stroke detection and lesion segmentation. This is achieved by discussing the state of the art approaches proposed by the recent works in this field.

METHODS

In this study, the advancements in stroke lesion detection and segmentation were focused. The survey analyses 113 research papers published in different academic research databases. The research articles have been filtered out based on specific criteria to obtain the most prominent insights related to stroke lesion detection and segmentation.

RESULTS

The features of the stroke lesion vary based on the type of imaging modality. To develop an effective method for stroke lesion detection, the features need to be carefully extracted from the input images. This review takes an attempt to categorize and discuss the different deep architectures employed for stroke lesion detection and segmentation, based on the underlying imaging modality. This further assists in understanding the relevance of the two-deep neural network components in medical image analysis namely Convolutional Neural Network (CNN) and Fully Convolutional Network (FCN). It hints at other possible deep architectures that can be proposed for better results towards stroke lesion detection. Also, the emerging trends and breakthroughs in stroke detection have been detailed in this evaluation.

CONCLUSION

This work concludes by examining the technical and non-technical challenges faced by researchers and indicate the future implications in stroke detection. It could support the bio-medical researchers to propose better solutions for stroke lesion detection.

Perioperative Ischemic and Hemorrhagic Stroke in Spine Surgery: A Series of 5 Cases

BACKGROUND

Stroke is a potentially life-threatening condition that can lead to disability and prolonged hospital stay. Perioperative stroke is a rare complication of spine surgery, especially in elective procedures. The prevalence of this complication varies in the literature, and the physiopathology is uncertain in many cases. Our objective was to describe 5 cases of patients who underwent spine surgery complicated by perioperative stroke and to analyze their characteristics and clinical outcomes.

METHODS

We retrospectively analyzed data from spine surgeries performed at a single institution from January 2016 to December 2019. Patients who presented with perioperative stroke were included. Data related to patient demographics, postoperative status, hospital stay, type of surgery, American Society of Anesthesiologists (ASA) score, neurologic status at discharge, and mortality were registered.

RESULTS

Five of 1002 consecutive patients (0.49%) had complication of stroke during surgery. The surgeries included occipitocervical fusion, anterior cervical fusion, lumbar fusion, lumbosacral fusion, and thoracolumbar fusion. The mean age of patients was 52.2 ± 15.73 years (range, 39-78 years), and the mean time of hospitalization was 20 ± 26.93 days (range, 6-68 days). The majority of patients were women (80%). Three patients (60%) presented with ischemic stroke, and 2 patients (40%) had hemorrhagic stroke. Two patients were severely disabled, and 3 showed good neurologic outcomes; no in-hospital deaths were observed. The etiology of stroke remained uncertain in the majority of cases.

CONCLUSIONS

Despite the rarity of this complication, perioperative stroke in spine surgery can lead to considerable morbidity. Precocious diagnosis and treatment may improve patient outcomes.

Timing of Recognition for Perioperative Strokes Following Cardiac Surgery

INTRODUCTION

More than half of reported perioperative strokes following cardiac surgery are identified beyond postoperative day one. The objective of our study was to determine preoperative and intraoperative factors that are associated with stroke following cardiac surgery and to identify factors that may contribute delayed recognition of perioperative stroke.

METHODS

Patients undergoing coronary artery bypass surgery or isolated valve surgery from January 2, 2015 to April 28, 2017 at an academic health system were identified from the Society of Thoracic Surgeons Registry. We determined preoperative and intraoperative factors associated with perioperative stroke. Two neurologists performed retrospective chart reviews on perioperative stroke patients to determine the last seen well time and the stroke cause.

RESULTS

During the study period, 2795 patients underwent coronary artery bypass surgery or isolated valve surgery (mean age 64 ± 11 years, 71% male, 72% Caucasian, 9% history of stroke), of which 43 (1.5%) had a perioperative stroke; 31 (72%) patients had an embolic mechanism of stroke based on neuroimaging. In multivariable analysis, perioperative strokes were independently associated with increasing age (OR 1.04, 95% 1.01-1.07), history of stroke (OR 2.73, 95% CI 1.47-5.06), and history of thoracic aorta disease (OR 3.36, 95% CI 1.16-9.71). Strokes were identified after postoperative day one in 32 (74%) patients of which 26 (81%) had a preoperative last seen well time.

CONCLUSION

Given the high frequency of preoperative last seen well time in perioperative stroke patients who are identified after postoperative day one, delayed stroke recognition may contribute to the bimodal distribution in timing of perioperative stroke. Frequent neurological monitoring within 24 hours after CABG or isolated valve surgery should be considered for all patients undergoing cardiac surgery, particularly elderly patients and those with a history of stroke or thoracic aorta disease, to improve early stroke recognition.

Relationship between bone disorders and stroke

Bone disorders are among the most uncommon causes of stroke, but they should be considered as stroke cause in particular clinical scenarios. On the other hand, osteoporosis/osteopenia and increased fracture risk are well documented post stroke complications. The relationship between stroke and bone health is complex. The current facts suggest that these two conditions share same risk factors, but also are risk factors for each other. However, the evidence shows more clear effect of stroke on the bone health, than in the opposite direction. This extensive review is aiming to fill the huge gap of evidence about this topic, and since bone pathology is extremely rare cause of cerebrovascular accident, although a complex connection between these two conditions definitely exists.

miR-98 reduces endothelial dysfunction by protecting blood-brain barrier (BBB) and improves neurological outcomes in mouse ischemia/reperfusion stroke model

Most neurological diseases, including stroke, lead to some degree of blood-brain barrier (BBB) dysfunction. A significant portion of BBB injury is caused by inflammation, due to pro-inflammatory factors produced in the brain, and by leukocyte engagement of the brain endothelium. Recently, microRNAs (miRNAs) have appeared as major regulators of inflammation-induced changes to gene expression in the microvascular endothelial cells (BMVEC) that comprise the BBB. However, miRNAs' role during cerebral ischemia/reperfusion is still underexplored. Endothelial levels of miR-98 were significantly altered following ischemia/reperfusion insults, both in vivo and in vitro, transient middle cerebral artery occlusion (tMCAO), and oxygen-glucose deprivation (OGD), respectively. Overexpression of miR-98 reduced the mouse's infarct size after tMCAO. Further, miR-98 lessened infiltration of proinflammatory Ly6C^HI leukocytes into the brain following stroke and diminished the prevalence of M1 (activated) microglia within the impacted area. miR-98 attenuated BBB permeability, as demonstrated by changes to fluorescently-labeled dextran penetration in vivo and improved transendothelial electrical resistance (TEER) in vitro. Treatment with miR-98 improved significantly the locomotor impairment. Our study provides identification and functional assessment of miRNAs in brain endothelium and lays the groundwork for improving therapeutic approaches for patients suffering from ischemic attacks.

Management of Acute Ischemic Stroke-Specific Focus on Anesthetic Management for Mechanical Thrombectomy

Acute ischemic stroke is a neurological emergency with a high likelihood of morbidity, mortality, and long-term disability. Modern stroke care involves multidisciplinary management by neurologists, radiologists, neurosurgeons, and anesthesiologists. Current American Heart Association/American Stroke Association (AHA/ASA) guidelines recommend thrombolytic therapy with intravenous (IV) alteplase within the first 3-4.5 hours of initial stroke symptoms and endovascular mechanical thrombectomy within the first 16-24 hours depending on specific inclusion criteria. The anesthesia and critical care provider may become involved for airway management due to worsening neurologic status or to enable computerized tomography (CT) or magnetic resonance imaging (MRI) scanning, to facilitate mechanical thrombectomy, or to manage critical care of stroke patients. Existing data are unclear whether the mechanical thrombectomy procedure is best performed under general anesthesia or sedation. Retrospective cohort trials favor sedation over general anesthesia, but recent randomized controlled trials (RCT) neither suggest superiority nor inferiority of sedation over general anesthesia. Regardless of anesthesia type, a critical element of intraprocedural stroke care is tight blood pressure management. At different phases of stroke care, different blood pressure targets are recommended. This narrative review will focus on the anesthesia and critical care providers' roles in the management of both perioperative stroke and acute ischemic stroke with a focus on anesthetic management for mechanical thrombectomy.

Pathophysiology, Mechanism, and Outcome of Ischemic Stroke in Cancer Patients

OBJECTIVES

The purpose of this study is to assess the risk factors, biomarkers of stroke, mechanism, and outcomes of cerebral infarction among cancerous diseases.

MATERIALS & METHODS

156 patients presented by acute ischemic stroke were divided into two groups: the first group included 78 ischemic stroke patients associated with different types of cancer and the second group (control group) included 78 ischemic stroke patients not associated with cancer. Both groups were compared regarding the risk factors, previous thrombotic activity, subtypes, biomarkers of stroke, and outcomes.

RESULTS

Cancer patients presented by acute ischemic stroke were accompanied by a significantly less incidence of diabetes mellitus, hypertension, dyslipidemia, and coronary heart disease, and atrial fibrillation than non-cancer patients (P < 0.001). While, levels of biomarkers of inflammation like erythrocyte sedimentation rate and C-reactive protein, and stroke biomarkers like fibrinogen, and D-dimer, all together were highly elevated in cancerous disease group of patients (P < 0.01). The prevalence of deep vein thrombosis, pulmonary embolism, and myocardial infarction was significantly higher in patients with cancer than in control patients without cancer (P = 0.008, P < 0.01 and P < 0.01 respectively). The most common stroke etiologies were atherosclerosis of large arteries and stroke of undetermined cause in a cancerous group of patients. Cancer patients were accompanied by significant higher mortality rate (P = 0.005), and more disability as determined by mRS (P < 0.005) CONCLUSIONS: Pathophysiology and mechanism of ischemic stroke in cancerous disease patients were due to different risk factors, biomarkers of stroke, and subtypes in comparison with non- cancerous cases.

Last Electrically Well: Intraoperative Neurophysiological Monitoring for Identification and Triage of Large Vessel Occlusions

INTRODUCTION

Intra-operative stroke (IOS) is associated with poor clinical outcome as detection is often delayed and time of symptom onset or patient's last known well (LKW) is uncertain. Intra-operative neurophysiological monitoring (IONM) is uniquely capable of detecting onset of neurological dysfunction in anesthetized patients, thereby precisely defining time last electrically well (LEW). This novel parameter may aid in the detection of large vessel occlusion (LVO) and prompt treatment with endovascular thrombectomy (EVT).

METHODS

We performed a retrospective analysis of a prospectively maintained AIS and LVO database from May 2018-August 2019. Inclusion criteria required any surgical procedure under general anesthesia (GA) utilizing EEG (electroencephalography) and/or SSEP (somatosensory evoked potentials) monitoring with development of intraoperative focal persistent changes using predefined alarm criteria and who were considered for EVT.

RESULT

Five cases were identified. LKW to closure time ranged from 66 to 321 minutes, while LEW to closure time ranged from 43 to 174 min. All LVOs were in the anterior circulation. Angiography was not pursued in two cases due to large established infarct (both patients expired in the hospital). EVT was pursued in two cases with successful recanalization and spontaneous recanalization was noted in one patient (mRS 0-3 at 90 days was achieved in all 3 cases).

CONCLUSIONS

This study demonstrates that significant IONM changes can accurately identify patients with an acute LVO in the operative setting. Given the challenges of recognizing peri-operative stroke, LEW may be an appropriate surrogate to quickly identify and treat IOS.

Cognitive declines after perioperative covert stroke: Recent advances and perspectives

PURPOSE OF REVIEW

With the aging of the population, there are increasing number of aged patients who require surgical interventions. Perioperative covert stroke is emerging as an important health threat and social burden that could affect patients' long-term neurological outcomes.

RECENT FINDINGS

Recent findings of the association between perioperative covert stroke with long-term cognitive declines of surgical patients highlighted the significance of the silent cognitive function killer-perioperative covert stroke. Considering the devastating long-term consequence of the asymptomatic covert stroke, early diagnosis and prevention are turning out as crucial problems to tackle. The evolving brain imaging techniques, such as multimodel MRI sequences are not only able to detect early, small and subtle injuries of the acute ischemic lesions, but also quite advantageous in capturing the preexisting brain vascular diseases that are considered as important risk factors of covert stroke. However, effective predictive markers are still lacking to identify high risk patients for perioperative covert stroke, rendering an unmet need of investigations in this regard.

SUMMARY

The present review will summarize recent findings in perioperative covert stroke and highlight future perspectives of its early diagnosis and the impact of postoperative cognitive impairments.

Perioperative Stroke in a Patient Undergoing Noncardiac, Non-Neurosurgical Procedure: A Case Report

Perioperative stroke is a focal or global neurological deficit lasting more than 24 hours, which occurs during the surgery or within 30 days following surgery. Medications administered during anesthesia mask the symptoms of stroke in the perioperative period and make the early diagnosis of stroke difficult. Postoperative endothelial dysfunction and surgery-induced hypercoagulable state are some of the factors contributing to perioperative stroke. This report describes a case of perioperative stroke in a patient with an unremarkable intraoperative course following otolaryngology surgery. Vigilance, early diagnosis, and prompt treatment with the help of the acute stroke team are pivotal in improving patient outcomes.

[Perioperative stroke]

Perioperative stroke is defined as an ischemic cerebrovascular event that occurs during or within 30 days after surgery and is associated with an increased perioperative risk of morbidity and mortality. Depending on the type of surgery stroke is diagnosed in up to 11% of all patients in the perioperative period. Patients with a history of ischemic stroke or transitory ischemic attack have an increased risk for perioperative stroke. Therefore, a critical assessment of indications and the timing of surgery are crucial to prevent recurring stroke in this patient population. Importantly, individualized blood pressure management is essential for optimization of cerebral perfusion during the perioperative period.This article provides a summary of the epidemiology, risk factors, and etiology of perioperative stroke. Moreover, possible preventive strategies relevant for the anesthesiologist are reviewed.