Incidence, Predictors, and Outcomes of Perioperative Stroke in Noncarotid Major Vascular Surgery

Barriers to Antiplatelet and Statin Adherence Following Major Vascular Intervention

OBJECTIVES

Antiplatelet and statins therapies are associated with improved cardiovascular outcomes following major vascular intervention. Many vascular surgery institutions are reporting improved prescribing rates for aspirin, P2Y12 antagonists, and statins. Nevertheless, there remains limited publication describing rates and patient-perceived barriers for postoperative adherence. The purpose of this study is to investigate patient non-adherence to antiplatelet and statin therapies following major vascular intervention.

METHODS

A retrospective review of patients who underwent major vascular intervention at a single academic center was performed. The prescribing rates of aspirin, P2Y12 antagonists, and statins were reviewed. Postoperative adherence, defined as consistent intake as prescribed, was evaluated at 1, 3, 6, 9, and 12 months using electronic documentation of both follow-up clinic appointments and phone call assessments then corroborated with pharmacy fulfillment records. Patient-reported barriers for medication adherence were also examined.

RESULTS

A total of 101 subjects underwent major vascular intervention between January 2020 and July 2020, 98% of whom were discharged on at least one antiplatelet or statin agent. Approximately 90% of patients were discharged with aspirin, 32% with a P2Y12 antagonist, and 96% with a statin. All patients who maintained adherence up to 6 months continued to report adherence at 9 and 12 months. Consistent adherence at 12 months was documented in 76% of patients on aspirin, 81% on P2Y12 antagonism therapy, and 73% on statins. New adverse drug reactions represented the most common barrier to achieving adherence (37%[n=20]). Preoperative therapy with aspirin, P2Y12 antagonists, and statins were all independently predictive for postoperative adherence to the same regimen (p<0.001). Female gender was also associated with higher rates of adherence to postoperative P2Y12 antagonism therapy (p<0.05).

CONCLUSIONS

The current prescribing rates for antiplatelet and statin agents are promising, but postoperative non-adherence remains a multifaceted issue.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Evaluating a Novel EEG-Based Index for Stroke Detection Under Anesthesia During Mechanical Thrombectomy

BACKGROUND

The rapid identification of acute stroke (AS) during and after anesthesia might lead to early interventions and improved outcomes. We investigated a novel 2-channel electroencephalogram (EEG)-based marker for stroke detection-the lateral interconnection ratio (LIR)-in AS patients having endovascular thrombectomy (EVT) with general anesthesia (GA) or sedation. The LIR in 2 reference groups of patients without postoperative neurological complications was used for comparison.

METHODS

The National Institutes of Health stroke scale score was assessed before and after thrombectomy in 100 patients having EVT with GA or sedation. The EEG was monitored during and for 4 hours following EVT in the AS group and during surgery in the 2 reference groups. We compared: (1) LIR between AS and reference groups; (2) LIR and stroke dynamics (clinical improvement or deterioration after EVT assessed by the National Institutes of Health stroke scale score); (3) the impact of stroke site (anterior vs. posterior circulation) and anesthesia type (GA vs. sedation) on the LIR.

RESULTS

Median (interquartile range) LIR was lower in patients with AS compared with reference patients (0.09, 0.05 to 0.16 vs. 0.39, 0.24 to 0.52, respectively; P <0.000002), and LIR increased in AS patients whose clinical status recovered after EVT compared with nonrecovered patients (0.20, 0.12 to 0.29 vs. 0.09, 0.05 to 0.11, respectively; P <0.007). The LIR might be more sensitive to anterior circulation stroke but is not impacted by anesthesia type.

CONCLUSIONS

We demonstrated the utility of using AS patients undergoing EVT as a platform for assessing a novel EEG marker for the identification of stroke during anesthesia. Further, large-scale studies in AS patients during EVT and in patients undergoing different surgeries and anesthesia are required to validate the LIR.

The elderly in the post-anesthesia care unit

It is increasingly conceivable that elderly patients will be treated in perioperative settings as the world's population shifts toward an older age distribution. They are more prone to a variety of unfavorable outcomes as a consequence of the physiological changes that accompany aging and the coexistence of multiple medical conditions. Postoperative complications in elderly patients are linked to a large increase in morbidity and mortality and the burden placed on the healthcare system. Our goal is to determine how elderly patients' recovery after anesthesia differs from that of younger patients. In addition, we will discuss the main postoperative complications experienced by elderly patients and the measures that are utilized to limit the risk of these complications developing.

Prevention of perioperative stroke in patients undergoing non-cardiac surgery

About 300 million adults undergo non-cardiac surgery annually. Although, in this setting, the incidence of perioperative stroke is low, the absolute number of patients experiencing a stroke is substantial. Furthermore, most patients with this complication will die or end up with severe disability. Covert brain infarctions are more frequent than overt strokes and are associated with postoperative delirium, cognitive decline, and cerebrovascular events at 1 year after surgery. Evidence shows that traditional stroke risk factors including older age, hypertension, and atrial fibrillation are also associated with perioperative stroke; previous stroke is the strongest risk factor for perioperative stroke. Increasing evidence also suggests the pathogenic role of perioperative events, such as hypotension, new atrial fibrillation, paradoxical embolism, and bleeding. Clinicians involved in perioperative care should be aware of this evidence on prevention strategies to improve patient outcomes after non-cardiac surgery.

Risk factors for postoperative acute ischemic stroke in advanced-aged patients with previous stroke undergoing noncardiac surgery: a retrospective cohort study

BACKGROUND

The current study aimed to investigate the incidence and risk factors for postoperative acute ischemic stroke (PAIS) in advanced-aged patients (≥ 75 years) with previous ischemic stroke undergoing noncardiac surgery.

METHODS

In this single-center retrospective cohort study, all advanced-aged patients underwent noncardiac surgery from 1 January, 2019, to 30 April, 2022. Data were extracted from hospital electronic medical records. Multivariable logistic regression analysis was performed to determine predictors of PAIS. Multivariable linear or logistic regression analysis was performed to determine predictors of outcomes due to PAIS.

RESULTS

Twenty-four patients (6.0%) of the 400 patients developed PAIS. Carotid endarterectomy (CEA), length of surgery and preoperative Modified Rankin scale (mRS) ≥ 3 were significant predictors of PAIS. CEA was associated with increased risk of PAIS (OR 4.14; 95%CI, 1.43-11.99). Each additional minute in length of surgery had slightly increased the risk of PAIS (OR, 1.01; 95%CI, 1.00-1.01). Compared with reference (mRS < 3), mRS ≥ 3 increased odds of PAIS (OR, 4.09;95%CI, 1.12-14.93). Surgery type and length of surgery were found to be significant predictors of in-hospital expense (P < 0.001) and hospital stays (P < 0.05).

CONCLUSIONS

CEA, length of surgery and preoperative mRS ≥ 3 may increase the development of PAIS in advanced-aged patients (≥ 75 years) with previous stroke undergoing noncardiac surgery. PAIS increased in-hospital mortality and prolonged hospital stay.

Focus on the Most Common Paucisymptomatic Vasculopathic Population, from Diagnosis to Secondary Prevention of Complications

Middle-aged adults can start to be affected by some arterial diseases (ADs), such as abdominal aortic or popliteal artery aneurysms, lower extremity arterial disease, internal carotid, or renal artery or subclavian artery stenosis. These vasculopathies are often asymptomatic or paucisymptomatic before manifesting themselves with dramatic complications. Therefore, early detection of ADs is fundamental to reduce the risk of major adverse cardiovascular and limb events. Furthermore, ADs carry a high correlation with silent coronary artery disease (CAD). This study focuses on the most common ADs, in the attempt to summarize some key points which should selectively drive screening. Since the human and economic possibilities to instrumentally screen wide populations is not evident, deep knowledge of semeiotics and careful anamnesis must play a central role in our daily activity as physicians. The presence of some risk factors for atherosclerosis, or an already known history of CAD, can raise the clinical suspicion of ADs after a careful clinical history and a deep physical examination. The clinical suspicion must then be confirmed by a first-level ultrasound investigation and, if so, adequate treatments can be adopted to prevent dreadful complications.

Development and validation of a prediction model to predict major adverse cardiovascular events in elderly patients undergoing noncardiac surgery: A retrospective cohort study

BACKGROUND AND AIMS

Current existing predictive tools have limitations in predicting major adverse cardiovascular events (MACEs) in elderly patients. We will build a new prediction model to predict MACEs in elderly patients undergoing noncardiac surgery by using traditional statistical methods and machine learning algorithms.

METHODS

MACEs were defined as acute myocardial infarction (AMI), ischemic stroke, heart failure and death within 30 days after surgery. Clinical data from 45,102 elderly patients (≥65 years old), who underwent noncardiac surgery from two independent cohorts, were used to develop and validate the prediction models. A traditional logistic regression and five machine learning models (decision tree, random forest, LGBM, AdaBoost, and XGBoost) were compared by the area under the receiver operating characteristic curve (AUC). In the traditional prediction model, the calibration was assessed using the calibration curve and the patients' net benefit was measured by decision curve analysis (DCA).

RESULTS

Among 45,102 elderly patients, 346 (0.76%) developed MACEs. The AUC of this traditional model was 0.800 (95% CI, 0.708-0.831) in the internal validation set, and 0.768 (95% CI, 0.702-0.835) in the external validation set. In the best machine learning prediction model-AdaBoost model, the AUC in the internal and external validation set was 0.778 and 0.732, respectively. Besides, for the traditional prediction model, the calibration curve of model performance accurately predicted the risk of MACEs (Hosmer and Lemeshow, p = 0.573), the DCA results showed that the nomogram had a high net benefit for predicting postoperative MACEs.

CONCLUSIONS

This prediction model based on the traditional method could accurately predict the risk of MACEs after noncardiac surgery in elderly patients.

Global trends in perioperative stroke research from 2003 to 2022: a web of science-based bibliometric and visual analysis

Background

Perioperative stroke is a potentially devastating complication in surgical patients, which has attracted global attention. This retrospective bibliometric and visual analysis evaluates the status and global trends in perioperative stroke research.

Methods

Papers published between 2003 and 2022 were retrieved from the Web of Science core collection. Extracted data were summarized and analyzed using Microsoft Excel and further bibliometric and co-occurrence analyses were conducted using VOSviewer and CiteSpace software.

Results

Publications on perioperative stroke have increased over the years. The USA topped the list of countries with the highest number of publications and citations, while Canada had the highest mean citation frequency. The Journal of Vascular Surgery and Annals of Thoracic Surgery had the highest number of publications and citation frequency for perioperative stroke. Regarding authors, Malas, Mahmoud B. contributed the most publications to the field, and Harvard University had the highest number of publications (409 papers). Based on an overlay visualization map, timeline view, and the strongest strength burst of keywords, "antiplatelet therapy," "antithrombotic therapy," "carotid revascularization," "bleeding complications," "postoperative cognitive dysfunction," "intraoperative hypotension," "thrombectomy," "cerebral revascularization," "valve surgery," "tranexamic acid," and "frozen elephant trunk" were trending topics in perioperative stroke research.

Conclusion

Publications regarding perioperative stroke have experienced rapid growth in the past 20 years and are likely to continuously increase. Research on perioperative antiplatelet and antithrombotic, cardiovascular surgery, postoperative cognitive dysfunction, thrombectomy, tranexamic acid, and frozen elephant trunk has attracted increasing attention, and these topics are emerging hotspots of present research and possible candidates for future research.

Comparison of upper extremity and transfemoral access for fenestrated-branched endovascular aortic repair

OBJECTIVE

The use of upper extremity (UE) access is an accepted and often implemented approach for fenestrated/branched endovascular aortic aneurysm repair (F-BEVAR). The advent of steerable sheaths has enabled the performance of F-BEVAR using a total transfemoral (TF) approach without UE access, potentially decreasing the risks of cerebral embolic events. The purpose of the present study was to assess the outcomes of F-BEVAR using UE vs TF access.

METHODS

Prospectively collected data from nine physician-sponsored investigational device exemption studies at U.S. centers were analyzed using a standardized database. All patients were treated for complex abdominal aortic aneurysms (CAAAs) and thoracoabdominal aortic aneurysms (TAAAs) using industry-manufactured fenestrated and branched stent grafts between 2005 and 2020. The outcomes were compared between patients who had undergone UE vs total TF access. The primary composite outcome was stroke or transient ischemia attack (TIA) and 30-day or in-patient mortality during the perioperative period. The secondary outcomes included technical success, local access-related complications, and perioperative mortality.

RESULTS

Among 1681 patients (71% men; mean age, 73.43 ± 7.8 years) who had undergone F-BEVAR, 502 had had CAAAs (30%), 535 had had extent IV TAAAs (32%), and 644 had had extent I to III TAAAs (38%). UE access was used for 1103 patients (67%). The right side was used for 395 patients (24%) and the left side for 705 patients (42%). UE access was preferentially used for TAAAs (74% vs 47%; P < .001). In contrast, TF access was used more frequently for CAAAs (53% vs 26%; P < .01). A total of 38 perioperative cerebrovascular events (2.5%), including 32 strokes (1.9%) and 6 TIAs (0.4%), had occurred. Perioperative cerebrovascular events had occurred more frequently with UE access than with TF access (2.8% vs 1.2%; P = .036). An individual component analysis of the primary composite outcome revealed a trend for more frequent strokes (2.3% vs 1.2%; P = .13) and TIAs (0.54% vs 0%; P = .10) in the UE access group. On multivariable analysis, total TF access was associated with a 60% reduction in the frequency of perioperative cerebrovascular events (odds ratio, 0.39; P = .029). No significant differences were observed between UE and TF access in the technical success rate (96.5% vs 96.8%; P = .72), perioperative mortality (2.9% vs 2.6%; P = .72), or local access-related complications (6.5% vs 5.5%; P = .43).

CONCLUSIONS

In the present large, multicenter, retrospective analysis of prospectively collected data, a total TF approach for F-BEVAR was associated with a lower rate of perioperative cerebrovascular events compared with UE access. Although the cerebrovascular event rate was low with UE access, the TF approach offered a lower risk of stroke and TIA. UE access will continue to play a role for appropriately selected patients requiring more complex repairs with anatomy not amenable to the TF approach.

Update in Carotid Disease

This review of the literature analyzes publications over the past five years on various problems associated with carotid endarterectomy: 1. Is the eversion or classical technique of surgery with plastic repair of the reconstruction area with a patch more effective? 2. Carotid endarterectomy or carotid angioplasty with stenting is more optimal? 3. When should brain revascularization be performed after the development of ischemic stroke? 4. Should a temporary shunt be used to protect the brain during carotid endarterectomy? 5. How to prevent and treat different types of intraoperative ischemic strokes? 6. What tactics of treatment of patients with combined lesions of the carotid and coronary arteries is more effective? 7. What are the causes and methods of elimination of restenosis of the internal carotid artery known? 8. Is carotid endarterectomy safe in old age?

Critical Care of the Vascular Surgery Patient

Patients that require major vascular surgery suffer from widespread atherosclerosis and have multiple comorbidities that place them at increased risk for postoperative complications and require admission to the intensive care unit (ICU). Postoperative critical care of these patients is focused on hemodynamic optimization, and early identification and management of complications to improve outcomes.

Navigating Antiplatelet Treatment Options for Stroke: Evidence-Based and Pragmatic Strategies

PURPOSE OF REVIEW

The benefit of using antiplatelet monotherapy in acute ischemic stroke and secondary stroke prevention is well established. In the last few years, several large randomized trials showed that the use of short-term dual antiplatelet therapy in particular stroke subtypes may reduce the risk of recurrent ischemic events. The aim of this article is to provide a critical analysis of the current evidence and recommendations for the use of antiplatelet agents for stroke prevention.

RECENT FINDINGS

Long-term therapy with aspirin, clopidogrel, or aspirin plus extended-release dipyridamole is recommended for secondary stroke prevention in patients with noncardioembolic ischemic stroke. Short-term dual antiplatelet therapy with aspirin and clopidogrel is superior to antiplatelet monotherapy in secondary stroke prevention when used in patients with mild noncardioembolic stroke or high-risk transient ischemic attack. Dual therapy, however, is associated with an increased risk of major bleeding, particularly when the treatment is extended for greater than 30 days. Similarly, aspirin plus ticagrelor is superior to aspirin monotherapy for the prevention of recurrent ischemic stroke, although this combination is associated with a higher risk of hemorrhagic complications when compared to other dual antiplatelet regimens. Among patients who carry CYP2C19 genetic polymorphisms associated with a slow bioactivation of clopidogrel, short-term treatment with aspirin plus ticagrelor is superior to aspirin plus clopidogrel for the reduction of recurrent stroke; however, the use of ticagrelor is associated with a higher risk of any bleeding. In patients with symptomatic intracranial stenosis, aggressive medical management in addition to dual antiplatelet therapy up to 90 days is recommended. Antiplatelet therapy has an essential role in the management of ischemic stroke. The specific antiplatelet regimen should be individualized based on the stroke characteristics, time from symptom onset, and patient-specific predisposition to develop hemorrhagic complications.

Preoperative evaluation and perioperative management of patients undergoing major vascular surgery

Patients undergoing major vascular surgery have an increased risk of perioperative major adverse cardiovascular events (MACE). Accordingly, in this population, it is of particular importance to appropriately risk stratify patients' risk for these complications and optimize risk factors prior to surgical intervention. Comorbidities that portend a higher risk of perioperative MACE include coronary artery disease, heart failure, left-sided valvular heart disease, and significant arrhythmic burden. In this review, we provide a current approach to risk stratification prior to major vascular surgery and describe the strengths and weaknesses of different cardiac risk indices; discuss the role of noninvasive and invasive cardiac testing; and review perioperative pharmacotherapies.

Perioperative cardiovascular outcome in patients with coronary artery disease undergoing major vascular surgery: A retrospective cohort study

Background:

Major adverse cardiac events (MACE) are a major contributor to morbidity and mortality in patients undergoing major vascular surgeries. We aim to assess the incidence, risk factors, and outcome of MACE in patients with coronary artery disease (CAD) undergoing aortic surgeries.

Methods:

In this retrospective observational study, we included patients with CAD who underwent elective major vascular surgery, namely, thoracoabdominal aortic aneurysm repairs and vascular bypass surgeries for aorto-occlusive disease, in our institute from January 2010 to December 2019. The association of preoperative risk factors including revised cardiac risk index factors, functional status of patients, severity of CAD, and its treatment status and technique of anesthesia with occurrence of MACE was analyzed.

Results:

Medical records of 141 patients were studied. The incidence of perioperative MACE was 11.3% (16/141) and overall in-hospital mortality was 6.4% (9/141), all of them related to MACE; implicating a 56.2% mortality in patients who develop MACE. The odds of a patient who had undergone preoperative coronary revascularization to develop a MACE was higher than a nonrevascularized patient (odds ratio: 3.9; 95% confidence interval [CI], 1.34–11.34). There was found to be no benefit in the addition of epidural analgesia to general anesthesia in reducing perioperative MACE.

Conclusions:

Major vascular surgeries in patients with CAD are a highly morbid procedure and a perioperative MACE places them at a significantly high risk of mortality. Early detection of CAD and preoperative medical optimization can play a major role in reducing the risk of MACE.

Perioperative Stroke and Thirty-Day Hospital Readmission After Cardiac Surgeries: State Inpatient Database Study

BACKGROUND

Readmission rates are an important metric for evaluating healthcare quality. Stroke is a major complication following cardiac surgery. Our study aimed to evaluate the frequency and predictors of 30-day unplanned hospital readmission after cardiac surgeries and to evaluate the impact of perioperative stroke on readmission.

METHODS

Surgical discharge records spanning the years of 2008 through 2011 were analyzed utilizing California State Inpatient Database. International Classification of Diseases, ninth revision-Clinical Modification (ICD-9-CM) codes and Clinical Classification Software (CCS) codes were used to identify surgeries and variables of interest. Surgical records were then followed up for 30 days through linking admission records. Perioperative stroke was defined as brain infarction of ischemic or hemorrhagic etiology that occurred during or within 30 days after surgery.

RESULTS

Baseline characteristics associated with increased readmission rates were female gender, age above 65, non-white race, lower income, and increased number of comorbidities. Among 199,617 hospitalizations for cardiac surgeries, 1,817 (0.91%) patients developed perioperative stroke. The rate of readmission in perioperative stroke patients was 21.89%. They had a longer length of hospital stay and their discharge was vastly non-routine (84%). Our univariate analysis yielded significant association between stroke and readmission rates (odds ratio: 1.82, 95% confidence interval: 1.63 - 2.04). This association failed to remain significant upon controlling for other variables in our multivariate analysis.

CONCLUSION

Baseline patient characteristics and perioperative complications are significant predictors of readmission. More than one in five patients who develop a stroke after cardiac surgery are readmitted to the hospital within 30 days of discharge.

Sleep, Pain, and Cognition: Modifiable Targets for Optimal Perioperative Brain Health

The prevention of perioperative neurocognitive disorders is a priority for patients, families, clinicians, and researchers. Given the multiple risk factors present throughout the perioperative period, a multicomponent preventative approach may be most effective. The objectives of this narrative review are to highlight the importance of sleep, pain, and cognition on the risk of perioperative neurocognitive disorders and to discuss the evidence behind interventions targeting these modifiable risk factors. Sleep disruption is associated with postoperative delirium, but the benefit of sleep-related interventions is uncertain. Pain is a risk factor for postoperative delirium, but its impact on other postoperative neurocognitive disorders is unknown. Multimodal analgesia and opioid avoidance are emerging as best practices, but data supporting their efficacy to prevent delirium are limited. Poor preoperative cognitive function is a strong predictor of postoperative neurocognitive disorder, and work is ongoing to determine whether it can be modified to prevent perioperative neurocognitive disorders.

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.

A nomogram to predict the risk of postoperative intracranial rebleeding in patients with spontaneous intracranial hematoma

The 30-day mortality rate of spontaneous cerebral hemorrhage (ICH) is approximately 30-50%. Surgery may improve the prognosis of patients with severe ICH. However, ICH survivors after surgery still face the risks of postoperative intracranial rebleeding (PIB), and clinical tools that accurately predict the risk of PIB occurrence are not available. Therefore, a retrospective study was performed. The population was divided into two groups according to the occurrence of PIB. Univariate and multivariate logistic regression analyses were performed to screen risk factors for PIB. Next, an early PIB risk nomogram prediction model was constructed. In addition, the impact of PIB on the prognosis of ICH was evaluated. In total, 150 ICH patients were continuously enrolled in this study; 21 patients suffered from PIB, and the overall incidence of PIB was 14.0% (21/150). Coronary heart disease history, a lower GCS score, and subarachnoid hemorrhage absence were screened as risk factors for early PIB. The early PIB risk nomogram showed good calibration and discrimination with a concordance index of 0.807 (95% confidence interval (CI), 0.715-0.899), which was confirmed to be 0.788 through bootstrapping validation. In addition, a significant difference in discharged GOS scores (P = 0.043) was observed between the PIB group and the n-PIB group. These results showed that a history of coronary heart disease, a lower GCS score, and absence of subarachnoid hemorrhage were risk factors for early PIB. In addition, the early PIB risk nomogram prediction model exhibits good discrimination and calibration. The occurrence of PIB could reduce the prognosis of ICH patients.

Perioperative Care of Patients at High Risk for Stroke During or After Non-cardiac, Non-neurological Surgery: 2020 Guidelines From the Society for Neuroscience in Anesthesiology and Critical Care

Perioperative stroke is associated with considerable morbidity and mortality. Stroke recognition and diagnosis are challenging perioperatively, and surgical patients receive therapeutic interventions less frequently compared with stroke patients in the outpatient setting. These updated guidelines from the Society for Neuroscience in Anesthesiology and Critical Care provide evidence-based recommendations regarding perioperative care of patients at high risk for stroke. Recommended areas for future investigation are also proposed.

Outcome of Organ Dysfunction in the Perioperative Period

While intraoperative mortality has diminished greatly over the last several decades, the risk of death within 30 days of surgery remains stubbornly high and is ultimately related to perioperative organ failure. Perioperative strokes, while rare (<2% in noncardiac surgery), are associated with a more than 10-fold increase in mortality. Rapid identification and treatment are key to maximizing long-term outcomes. Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are separate but related perioperative neurological disorders, both of which are associated with poor long-term outcomes. To date, there are few known interventions that can ameliorate the risk of perioperative central nervous system dysfunction. Major adverse cardiac events (MACE) are a major contributor to adverse clinical outcomes following surgical procedures. Recently, advances in diagnostic strategies (eg, high-sensitivity cardiac troponin [hs-cTn] assays) have improved our understanding of MACE. Recently, the dabigatran in patients with myocardial injury after noncardiac surgery (MINS; Management of myocardial injury After NoncArdiac surGEry) trial demonstrated that a direct thrombin inhibitor could improve outcomes following MINS. While the risk of acute respiratory distress syndrome (ARDS) after surgery is approximately 0.2%, other less severe complications (eg, pneumonia, reintubation) are closer to 2%. While intensive care unit (ICU) concepts related to ARDS have migrated into the operating room, whether or not adverse pulmonary outcomes impact long-term outcomes in surgical patients remains a matter of debate. The standardization of acute kidney injury (AKI) definition has improved the ability of clinicians to measure and study the incidence of this important source of perioperative morbidity. AKI is associated with increased mortality as well as nonrenal morbidity (eg, myocardial infarction) after major surgery. Gastrointestinal complications after surgery range from ileus (common in abdominal procedures and associated with an increased length of stay) to less common complications such as mesenteric ischemia and gastrointestinal bleeding, both of which are associated with very high mortality. Outside of cardiothoracic surgery, the incidence of perioperative hepatic injury is not well described but, in this population, is associated with worsened long-term outcomes. Hyperglycemia is a common perioperative complication and occurs in patients undergoing both cardiac and noncardiac surgery. Both hyper- and hypoglycemia are associated with worsened long-term outcomes in cardiac and noncardiac surgery. Better diagnosis and increased understanding of perioperative organ injury has led to an increased appreciation for the specific role that particular organ systems play in poor long-term outcomes and has set the stage for targeted therapeutic interventions.

Postoperative Screening With the Modified National Institutes of Health Stroke Scale After Noncardiac Surgery: A Pilot Study

BACKGROUND

Perioperative stroke is associated with high rates of morbidity and mortality, yet there is no validated screening tool. The modified National Institutes of Health Stroke Scale (mNIHSS) is validated for use in nonsurgical strokes but is not well-studied in surgical patients. We evaluated perioperative changes in the mNIHSS score in noncardiac, non-neurological surgery patients, feasibility in the perioperative setting, and the relationship between baseline cognitive screening and change in mNIHSS score.

METHODS

Patients aged 65 years and above presenting for noncardiac, non-neurological surgery were prospectively recruited. Those with significant preoperative cognitive impairment (Montreal Cognitive Assessment score [MoCA] ≤17) were excluded. mNIHSS was assessed preoperatively, on postoperative day (POD) 0, POD 1, and POD 2, demographic data collected, and feedback solicited from participants. Changes in mNIHSS from baseline, time to completion, and relationship between baseline MoCA score and change in mNIHSS score were analyzed.

RESULTS

Twenty-five patients were enrolled into the study; no overt strokes occurred. Median mNIHSS score increased between baseline (0 interquartile range [IQR 0 to 1]) and POD 0 (2 [IQR 0 to 3.5]; P<0.001) but not between baseline and POD 1 (0.5 [IQR 0 to 1.5]; P=0.174) or POD 2 (0 [IQR 0 to 1]; P=0.650). Time to complete the mNIHSS at baseline was 3.5 minutes (SD 0.8), increasing to 4.1 minutes (SD 1.0) on POD 0 (P=0.0249). Baseline MoCA score was correlated with mNIHSS score change (P=0.038). Perioperative administration of the mNIHSS was feasible, and acceptable to patients.

CONCLUSIONS

Changes in mNIHSS score can occur early after surgery in the absence of overt stroke. Assessment of mNIHSS appears feasible in the perioperative setting, although further research is required to define its role in detecting perioperative stroke.

A nomogram to predict the risk of early postoperative ischemic events in patients with spontaneous intracranial hematoma

Spontaneous intracranial hematoma (ICH) is the second leading cause of stroke and has a high risk of postoperative ischemic events (PIEs). But, the evidence on PIEs in ICH patients still lacks. Therefore, a retrospective study was carried out to screen the risk factors for PIEs and construct a visual predictive model. This was a retrospective study whose population were divided into two groups based on the occurrence of PIEs. Univariate logistic regression analysis was used to determine factors associated with PIEs. Multifactorial logistic regression analysis was used to screen risk factors and construct the early PIEs risk nomogram. In addition, impact of PIEs on patient prognosis and surgery related costs was assessed. Out of 122 ICH patients, 24 (19.7%) were diagnosed with PIEs. Coronary heart disease history, ischemic stroke history, regular shaped hematoma and platelet number were identified as risk factors for early PIEs. Early PIEs risk nomogram showed good calibration and discrimination of the data with concordance index of 0.846 (95% confidence interval, 0.747-0.945) which was confirmed to be 0.827 through bootstrapping validation. In addition, there was statistical difference in discharged Glasgow Coma Scale score (P = 0.046) and surgery related costs (p = 0.031) between PIEs group and nPIEs group. These results showed the early PIEs risk nomogram was accurate for prediction risks of PIEs and the occurrence of PIEs affects prognosis of patients, and increases surgery related costs.

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.

RiPerC Attenuates Cerebral Ischemia Injury through Regulation of miR-98/PIK3IP1/PI3K/AKT Signaling Pathway

Background

Cerebral ischemic stroke is a refractory disease which seriously endangers human health. Remote ischemic perconditioning (RiPerC) by which the sublethal ischemic stimulus is administered during the ischemic event is beneficial after an acute stroke. However, the regulatory mechanism of RiPerC that relieves cerebral ischemic injury is still not completely clear.

Methods

In the present study, we investigated the regulatory mechanism of RiPerC in a rat model of ischemia induced by the middle cerebral artery occlusion (MCAO). Forty-eight adult male Sprague-Dawley (SD) rats were injected intracerebroventricularly with miR-98 agomir, miR-98 antagomir, or their negative controls (agomir-NC, antagomir-NC) 2 h before MCAO or MCAO+RiPerC followed by animal behavior tests and infraction volume measurement at 24 h after MCAO. The expression of miR-98, PIK3IP1, and tight junction proteins in rat hippocampus and cerebral cortex tissues was detected by quantitative polymerase chain reaction (qPCR) and Western blot (WB). Enzyme-linked immunosorbent assay (ELISA) was used to assess the IL-1β, IL-6, and TNF-α levels in the rat serum.

Results

The results showed that in MCAO group, the expression of PIK3IP1 was upregulated, but decreased after RiPerC treatment. Then, we found that PIK3IP1 was a potential target of miR-98. Treatment with miR-98 agomir decreased the infraction volume, reduced brain edema, and improved neurological functions compared to control rats. But treating with miR-98 antagomir in RiPerC group, the protective effect on cerebral ischemia injury was canceled.

Conclusion

Our finding indicated that RiPerC inhibited the MCAO-induced expression of PIK3IP1 through upregulated miR-98, thereby reducing the apoptosis induced by PIK3IP1 through the PI3K/AKT signaling pathway, thus reducing the cerebral ischemia-reperfusion injury.

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.

Interventions to improve perioperative neurologic outcomes

PURPOSE OF REVIEW

Few outcomes in surgery are as important to patients as that of their neurologic status. The purpose of this review is to discuss and categorize the most common perioperative neurologic complications. We will also discuss strategies to help prevent and mitigate these complications for our patients.

RECENT FINDINGS

There are several strategies the anesthesiologist can undertake to prevent or treat conditions, such as perioperative neurocognitive disorders, spinal cord ischemia, perioperative stroke, and postoperative visual loss.

SUMMARY

A thorough understanding of threats to patients' neurologic well-being is essential to excellent clinical practice.

[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.

let-7g counteracts endothelial dysfunction and ameliorating neurological functions in mouse ischemia/reperfusion stroke model

Stroke is a debilitating disease, accounting for almost 20% of all hospital visits, and 8% of all fatalities in the United States in 2017. Following an ischemic attack, inflammatory processes originating from endothelial cells within the brain microvasculature can induce many toxic effects into the impacted area, from both sides of the blood brain barrier (BBB). In addition to increased BBB permeability, impacted brain microvascular endothelial cells can recruit macrophages and other immune cells from the periphery and can also trigger the activation of microglia and astrocytes within the brain. We have identified a key microRNA, let-7g, which levels were drastically diminished as consequence of transient middle cerebral artery occlusion (tMCAO) in vivo and oxygen-glucose deprivation (OGD) in vitro ischemia/reperfusion conditions, respectively. We have observed that let-7g* liposome-based delivery is capable of attenuating inflammation after stroke, reducing BBB permeability, limiting brain infiltration by CD3+CD4+ T-cells and Ly6G+ neutrophils, lessening microglia activation and neuronal death. These effects consequently improved clinical outcomes, shown by mitigating post-stroke gait asymmetry and extremity motor function. Due to the role of the endothelium in propagating the effects of stroke and other inflammation, treatments which can reduce endothelial inflammation and limit ischemic damage and improving recovery after a stroke are required. Our findings demonstrate a critical link between the CNS inflammation and the immune system reaction and lay important groundwork for future stroke pharmacotherapies.

Perioperative Stroke

PURPOSE OF REVIEW

This review overviews perioperative stroke as it pertains to specific surgical procedures.

RECENT FINDINGS

As awareness of perioperative stroke increases, so does the opportunity to potentially improve outcomes for these patients by early stroke recognition and intervention. Perioperative stroke is defined to be any stroke that occurs within 30 days of the initial surgical procedure. The incidence of perioperative stroke varies and is dependent on the specific type of surgery performed. This chapter overviews the risks, mechanisms, and acute evaluation and management of perioperative stroke in four surgical populations: cardiac surgery, carotid endarterectomy, neurosurgery, and non-cardiac/non-carotid/non-neurological surgeries.

Cerebrovascular Complications After Upper Extremity Access for Complex Aortic Interventions: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this study was to review the risk of developing cerebrovascular complications from upper extremity access during endovascular treatment of complex aortic aneurysms.

METHODS

A systematic review and meta-analysis were conducted according to the PRISMA guideline. An electronic search of the public domains Medline (PubMed), Embase (Ovid), Web of Science and Cochrane Library was performed to identify studies related to the treatment of aortic aneurysms involving upper extremity access. Meta-analysis was used to compare the rate of cerebrovascular event after left, right and bilateral upper extremity access. Results are presented as relative risk (RR) and 95% confidence intervals (CIs).

RESULTS

Thirteen studies including 1276 patients with complex endovascular treatment of aortic aneurysms using upper extremity access were included in the systematic review. Left upper extremity access (UEA) was used in 1028 procedures, right access in 148 and bilateral access in 100 procedures. The rate of cerebrovascular complications for patients treated through left UEA was 1.7%, through right UEA 4% and through bilateral UEA 5%. In the meta-analysis, we included seven studies involving 645 patients treated with a left upper extremity access, 87 patients through a right and 100 patients through a bilateral upper extremity access. Patients, who underwent right-sided (RR 5.01, 95% CI 1.51-16.58, P = 0.008) or bilateral UEA (RR 4.57, 95% CI 1.23-17.04, P = 0.02), had a significantly increased risk of cerebrovascular events compared to those who had a left-sided approach.

CONCLUSION

Left upper extremity access is associated with a significantly lower rate of cerebrovascular complications as compared to right or bilateral upper extremity access.

A Multilevel Analysis of Surgical Category and Individual Patient-Level Risk Factors for Postoperative Stroke

Background and Purpose

Many studies supporting the association between specific surgical procedure categories and postoperative stroke (POS) do not account for differences in patient-level characteristics between and within surgical categories. The risk of POS after high-risk procedure categories remains unknown after adjusting for such differences in patient-level characteristics.

Methods

Using inpatients in the American College of Surgeons National Surgical Quality Initiative Program database, we conducted a retrospective cohort study between January 1, 2000, and December 31, 2010. Our primary outcome was POS within 30 days of surgery. We characterized the relationship between surgical- and individual patient-level factors and POS by using multivariable, multilevel logistic regression that accounted for clustering of patient-level factors with surgical categories.

Results

We identified 729 886 patients, 2703 (0.3%) of whom developed POS. Dependent functional status (odds ratio [OR]: 4.11, 95% confidence interval [95% CI]: 3.60-4.69), history of stroke (OR: 2.35, 95%CI: 2.06-2.69) or transient ischemic attack (OR: 2.49 95%CI: 2.19-2.83), active smoking (OR: 1.20, 95%CI: 1.08-1.32), hypertension (OR: 2.11, 95%CI: 2.19-2.82), chronic obstructive pulmonary disease (OR: 1.39 95%CI: 1.21-1.59), and acute renal failure (OR: 2.35, 95%CI: 1.85-2.99) were significantly associated with POS. After adjusting for clustering, patients who underwent cardiac (OR: 11.25, 95%CI: 8.52-14.87), vascular (OR: 4.75, 95%CI: 3.88-5.82), neurological (OR: 4.60, 95%CI: 3.48-6.08), and general surgery (OR: 1.40, 95%CI: 1.15-1.70) had significantly greater odds of POS compared to patients undergoing other types of surgical procedures.

Conclusions

Vascular, cardiac, and neurological surgery remained strongly associated with POS in an analysis accounting for the association between patient-level factors and surgical categories.

Perioperative Major Adverse Cardiovascular and Cerebrovascular Events Associated With Noncardiac Surgery

Importance

Major adverse cardiovascular and cerebrovascular events (MACCE) are a significant source of perioperative morbidity and mortality following noncardiac surgery.

Objective

To evaluate national trends in perioperative cardiovascular outcomes and mortality after major noncardiac surgery and to identify surgical subtypes associated with cardiovascular events using a large administrative database of United States hospital admissions.

Design, Setting, Participants

Patients who underwent major noncardiac surgery from January 2004 to December 2013 were identified using the National Inpatient Sample.

Main Outcomes and Measures

Perioperative MACCE (primary outcome), defined as in-hospital, all-cause death, acute myocardial infarction (AMI), or acute ischemic stroke, were evaluated over time.

Results

Among 10 581 621 hospitalizations (mean [SD] patient age, 65.74 [12.32] years; 5 975 798 female patients 56.60%]) for major noncardiac surgery, perioperative MACCE occurred in 317 479 hospitalizations (3.0%), corresponding to an annual incidence of approximately 150 000 events after applying sample weights. Major adverse cardiovascular and cerebrovascular events occurred most frequently in patients undergoing vascular (7.7%), thoracic (6.5%), and transplant surgery (6.3%). Between 2004 and 2013, the frequency of MACCE declined from 3.1% to 2.6% (P for trend <.001; adjusted odds ratio [aOR], 0.95; 95% CI, 0.94-0.97) driven by a decline in frequency of perioperative death (aOR, 0.79; 95% CI, 0.77-0.81) and AMI (aOR, 0.87; 95% CI, 0.84-0.89) but an increase in perioperative ischemic stroke from 0.52% in 2004 to 0.77% in 2013 (P for trend <.001; aOR 1.79; CI 1.73-1.86).

Conclusions and Relevance

Perioperative MACCE occurs in 1 of every 33 hospitalizations for noncardiac surgery. Despite reductions in the rate of death and AMI among patients undergoing major noncardiac surgery in the United States, perioperative ischemic stroke increased over time. Additional efforts are necessary to improve cardiovascular care in the perioperative period of patients undergoing noncardiac surgery.

Cerebrovascular Disease and Perioperative Neurologic Vulnerability: A Prospective Cohort Study

Background: Stroke is a devastating perioperative complication without effective methods for prevention or diagnosis. The objective of this study was to analyze evidence-based strategies for detecting cerebrovascular vulnerability and injury in a high-risk cohort of non-cardiac surgery patients.

Methods: This was a single-center, prospective cohort study. Fifty patients undergoing non-cardiac surgery were recruited −25 with known cerebrovascular disease and 25 matched controls. Neurologic vulnerability was measured with intraoperative cerebral oximetry as the primary outcome. Perioperative neurocognitive testing and serum biomarker analysis (S-100β, neuron specific enolase, glial fibrillary acid protein, and matrix metalloproteinase-9) were measured as secondary outcomes.

Results: Cerebral desaturation events (an oximetry decrease ≥20% from baseline or <50% absolute value for ≥3 min) occurred in 7/24 (29%) cerebrovascular disease patients and 2/24 (8.3%) controls (relative risk 3.5, 95% CI 0.81–15.2; P = 0.094). Cognitive function trends were similar in both groups, though overall scores (range: 1,500–7,197) were ~1 standard deviation lower in cerebrovascular patients across the entire perioperative period (−1,049 [95% CI −1,662, −436], P < 0.001). No significant serum biomarker differences were found between groups over time. One control patient experienced intraoperative hypoxic-ischemic injury, but no robust biomarker or oximetry changes were observed.

Conclusions: Cerebrovascular disease patients did not demonstrate dramatic differences in cerebral oximetry, cognitive trajectory, or molecular biomarkers compared to controls. Moreover, a catastrophic hypoxic-ischemic event was neither predicted nor detected by any strategy tested. These findings support the need for novel research into cerebrovascular risk and vulnerability.

Incidence and Risk Factors for Stroke in Fast-Track Hip and Knee Arthroplasty-A Clinical Registry Study of 24,862 Procedures

BACKGROUND

Postoperative stroke is a severe complication with a reported 30-day incidence of 0.4%-0.6% after total hip (THA) and knee arthroplasty (TKA). However, most data are based on diagnostic codes and with limited details on perioperative care, including the use of fast-track protocols. We investigated the incidence of and preoperative and postoperative factors for stroke after fast-track THA/TKA.

METHODS

We used an observational study design of elective fast-track THA/TKA patients with prospective collection of comorbidity and complete 90-day follow-up. Medical records were evaluated for events potentially disposing to stroke. Identification of relevant preoperative risk factors was done by multivariable logistic regression. Incidence of stroke was compared with a Danish background population.

RESULTS

Of 24,862 procedures with a median length of stay of 2 (interquartile range, 2-3) days, we found 27 (0.11%; 95% confidence interval [CI], 0.08%-0.16%) and 43 strokes (0.17%, 95% CI, 0.13%-0.23%) ≤30 and ≤90 days after surgery, respectively. Preoperative risk factors for stroke ≤30 days were age ≥ 85 years (odds ratio [OR], 4.3; 95% CI, 1.1-16.3) and anticoagulant treatment (OR, 3.1; 95% CI, 1.2-7.9). Preoperative anemia was near significant (OR, 2.1; 95% CI, 0.98-4.6, P = .055). Eight strokes ≤30 days were preceded by a cardiovascular event within the second postoperative day. Incidence of stroke after postoperative day 30 was similar to a Danish background population.

CONCLUSION

Risk of postoperative stroke in fast-track THA and TKA was low but may be further reduced with increased focus on avoiding perioperative cardiovascular events and in patients with preoperative anticoagulants or anemia.

Using machine learning techniques to develop forecasting algorithms for postoperative complications: protocol for a retrospective study

INTRODUCTION

Mortality and morbidity following surgery are pressing public health concerns in the USA. Traditional prediction models for postoperative adverse outcomes demonstrate good discrimination at the population level, but the ability to forecast an individual patient's trajectory in real time remains poor. We propose to apply machine learning techniques to perioperative time-series data to develop algorithms for predicting adverse perioperative outcomes.

METHODS AND ANALYSIS

This study will include all adult patients who had surgery at our tertiary care hospital over a 4-year period. Patient history, laboratory values, minute-by-minute intraoperative vital signs and medications administered will be extracted from the electronic medical record. Outcomes will include in-hospital mortality, postoperative acute kidney injury and postoperative respiratory failure. Forecasting algorithms for each of these outcomes will be constructed using density-based logistic regression after employing a Nadaraya-Watson kernel density estimator. Time-series variables will be analysed using first and second-order feature extraction, shapelet methods and convolutional neural networks. The algorithms will be validated through measurement of precision and recall.

ETHICS AND DISSEMINATION

This study has been approved by the Human Research Protection Office at Washington University in St Louis. The successful development of these forecasting algorithms will allow perioperative healthcare clinicians to predict more accurately an individual patient's risk for specific adverse perioperative outcomes in real time. Knowledge of a patient's dynamic risk profile may allow clinicians to make targeted changes in the care plan that will alter the patient's outcome trajectory. This hypothesis will be tested in a future randomised controlled trial.

Risks of Cardiovascular Adverse Events and Death in Patients with Previous Stroke Undergoing Emergency Noncardiac, Nonintracranial Surgery

Background

The outcomes of emergent noncardiac, nonintracranial surgery in patients with previous stroke remain unknown.

Methods

All emergency surgeries performed in Denmark (2005 to 2011) were analyzed according to time elapsed between previous ischemic stroke and surgery. The risks of 30-day mortality and major adverse cardiovascular events were estimated as odds ratios (ORs) and 95% CIs using adjusted logistic regression models in a priori defined groups (reference was no previous stroke). In patients undergoing surgery immediately (within 1 to 3 days) or early after stroke (within 4 to 14 days), propensity-score matching was performed.

Results

Of 146,694 nonvascular surgeries (composing 98% of all emergency surgeries), 5.3% had previous stroke (mean age, 75 yr [SD = 13]; 53% women, 50% major orthopedic surgery). Antithrombotic treatment and atrial fibrillation were more frequent and general anesthesia less frequent in patients with previous stroke (all P &lt; 0.001). Risks of major adverse cardiovascular events and mortality were high for patients with stroke less than 3 months (20.7 and 16.4% events; OR = 4.71 [95% CI, 4.18 to 5.32] and 1.65 [95% CI, 1.45 to 1.88]), and remained increased for stroke within 3 to 9 months (10.3 and 12.3%; OR = 1.93 [95% CI, 1.55 to 2.40] and 1.20 [95% CI, 0.98 to 1.47]) and stroke more than 9 months (8.8 and 11.7%; OR = 1.62 [95% CI, 1.43 to 1.84] and 1.20 [95% CI, 1.08 to 1.34]) compared with no previous stroke (2.3 and 4.8% events). Major adverse cardiovascular events were significantly lower in 323 patients undergoing immediate surgery (21%) compared with 323 successfully propensity-matched early surgery patients (29%; P = 0.029).

Conclusions

Adverse cardiovascular outcomes and mortality were greatly increased among patients with recent stroke. However, events were higher 4 to 14 days after stroke compared with 1 to 3 days after stroke.

[Postoperative cerebral dysfunction]

AIM

To study the structure, risk factors and methods of prevention of postoperative brain dysfunction on the example of coronary artery bypass surgery with cardiopulmonary bypass.

MATERIAL AND METHODS

The study included 77 patients who undergone elective coronary artery bypass surgery at the beating heart (22 patients) or with cardiopulmonary bypass (55 patients, including 24 patients, who received cerebroprotective treatment with cytoflavin in the preoperative period). All patients underwent dynamic (pre- and postoperative) neurological, neuropsychological, instrumental examinations.

RESULTS

The postoperative cerebral dysfunction was diagnosed in 34 (44,2%) patients. The frequency of the clinical types of postoperative cerebral dysfunction significantly differed: perioperative stroke - 3 (3,9%) cases, symptomatic delirium of the early postoperative period - 11 (14,3%) cases, delayed cognitive impairment - 28 (36,4%) cases. The risk factors of postoperative cerebral dysfunction after the coronary artery bypass surgery with cardiopulmonary bypass were identified. Preventive preoperative use of the neuroprotective drug cytoflavin reduces the severity of delayed cognitive impairment after the coronary artery bypass surgery with cardiopulmonary bypass and has a good safety profile.

CONCLUSION

An analysis of the literature data and the results of our own studies show that postoperative cerebral dysfunction is the nosological entity with various etiological factors, pathogenetic mechanisms and the characteristic clinical types, which has an effect on the outcome of surgical treatment.

Is Neck Dissection Associated with an Increased Risk of Postoperative Stroke?

Objective Prior studies have reported widely disparate rates of postoperative stroke, with conflicting analyses of whether neck dissection is an independent risk factor. Study Design Cohort study. Setting American College of Surgeons National Surgical Quality Improvement Program from 2005 to 2013. Subjects and Methods We compared the 30-day rate of postoperative stroke between patients undergoing complete or modified radical neck dissection and a control cohort composed of those undergoing resections in the oral cavity, oropharynx, larynx, or hypopharynx without neck dissection. Propensity scores and paired statistics were used to compare the groups while adjusting for relevant covariates. Results We identified 9697 patients, including 5827 with neck dissection and 3870 without neck dissection. In the full cohort, the rate of postoperative stroke was greater with neck dissection than without it (0.31% vs 0.11%, P = .052), although the relationship was attenuated by propensity score matching to adjust for comorbidities (0.30% vs 0.13%, P = .18). Among patients with ≥2 risk factors for carotid artery stenosis, neck dissection was associated with an increased rate of postoperative stroke (2.68% with bilateral neck dissection, 0.41% with unilateral neck dissection, and 0.24% without neck dissection, P = .04). The incidence of stroke was strongly associated with 30-day mortality (7.4% vs 0.2%, P < .001). Conclusions Stroke is a rare but highly morbid complication after head and neck surgery. Compared with other head and neck surgery, neck dissection in patients at risk for carotid artery stenosis is associated with an increased risk of postoperative stroke.