Silent Brain Injury After Cardiac Surgery: A Review

Postoperative cognitive dysfunction: a concept analysis

BACKGROUND

Post-operative cognitive dysfunction (POCD) is a concern for clinicians that often presents post-surgery where generalized anesthesia has been used. Its prevalence ranges from 36.6% in young adults to 42.4% in older individuals. Conceptual clarity for POCD is lacking in the currently body literature. Our two-fold purpose of this concept analysis was to (1) critically appraise the various definitions, while also providing the best definition, of POCD and (2) narratively synthesize the attributes, surrogate or related terms, antecedents (risk factors), and consequences of the concept.

METHOD

The reporting of our review was guided by the PRISMA statement and the 6-step evolutionary approach to concept analysis developed by Rodgers. Three databases, including Medline, CINAHL, and Web of Science, were searched to retrieve relevant literature on the concept of POCD. Two independent reviewers conducted abstract and full-text screening, data extraction, and appraisal. The review process yielded a final set of 86 eligible articles.

RESULT

POCD was defined with varying severities ranging from subtle-to-extensive cognitive changes (1) affecting single or multiple cognitive domains that manifest following major surgery (2), is transient and reversible, and (3) may last for several weeks to years. The consequences of POCD may include impaired quality of life, resulting from withdrawal from the labor force, increased patients' dependencies, cognitive decline, an elevated risk of dementia, rising healthcare costs, and eventual mortality.

CONCLUSION

This review resulted in a refined definition and comprehensive analysis of POCD that can be useful to both researchers and clinicians. Future research is needed to refine the operational definitions of POCD so that they better represent the defining attributes of the concept.

Intensive Blood Pressure Treatment and Subclinical Brain Infarcts: A Secondary Analysis of SPRINT (Systolic Pressure Intervention Trial)

OBJECTIVE

Subclinical brain infarcts (SBI) increase the risk for stroke and dementia, but whether they should be considered equivalent to symptomatic stroke when determining blood pressure targets remains unclear. We tested whether intensive systolic blood pressure (SBP) treatment reduced the risk of new SBI or stroke and determined the association between SBI and cognitive impairment.

METHODS

In this secondary analysis of SPRINT (Systolic Pressure Intervention Trial), participants ≥50 years old, with SBP 130-180mmHg and elevated cardiovascular risk but without known clinical stroke, dementia, or diabetes, were randomized to intensive (<120mmHg) or standard (<140mmHg) SBP treatment. Brain magnetic resonance images collected at baseline and follow-up were read for SBI. The occurrence of mild cognitive impairment (MCI) or probable dementia (PD) was evaluated.

RESULTS

For 667 participants at baseline, SBI were identified in 75 (11%). At median 3.9 years follow-up, 12 of 457 had new SBI on magnetic resonance imaging (5 intensive, 7 standard), whereas 8 had clinical stroke (4 per group). Baseline SBI (subhazard ratio [sHR] = 3.90; 95% CI 1.49 to 10.24; p = 0.006), but not treatment group, was associated with new SBI or stroke. For participants with baseline SBI, intensive treatment reduced their risk for recurrent SBI or stroke (sHR = 0.050; 95% CI 0.0031 to 0.79; p = 0.033). Baseline SBI also increased risk for MCI or PD during follow-up (sHR = 2.38; 95% CI 1.23 to 4.61; p = 0.010).

INTERPRETATION

New cerebral ischemic events were infrequent, but intensive treatment mitigated the increased risk for participants with baseline SBI, indicating primary prevention SBP goals are still appropriate when SBI are present. ANN NEUROL 2024;95:866-875.

Impact of inflammatory preconditioning on murine microglial proteome response induced by focal ischemic brain injury

Preconditioning with lipopolysaccharide (LPS) induces neuroprotection against subsequent cerebral ischemic injury, mainly involving innate immune pathways. Microglia are resident immune cells of the central nervous system (CNS) that respond early to danger signals through memory-like differential reprogramming. However, the cell-specific molecular mechanisms underlying preconditioning are not fully understood. To elucidate the distinct molecular mechanisms of preconditioning on microglia, we compared these cell-specific proteomic profiles in response to LPS preconditioning and without preconditioning and subsequent transient focal brain ischemia and reperfusion, - using an established mouse model of transient focal brain ischemia and reperfusion. A proteomic workflow, based on isolated microglia obtained from mouse brains by cell sorting and coupled to mass spectrometry for identification and quantification, was applied. Our data confirm that LPS preconditioning induces marked neuroprotection, as indicated by a significant reduction in brain infarct volume. The established brain cell separation method was suitable for obtaining an enriched microglial cell fraction for valid proteomic analysis. The results show a significant impact of LPS preconditioning on microglial proteome patterns by type I interferons, presumably driven by the interferon cluster regulator proteins signal transducer and activator of transcription1/2 (STAT1/2).

Infarct-related structural disconnection and delirium in surgical aortic valve replacement patients

OBJECTIVE

Although acute brain infarcts are common after surgical aortic valve replacement (SAVR), they are often unassociated with clinical stroke symptoms. The relationship between clinically "silent" infarcts and in-hospital delirium remains uncertain; obscured, in part, by how infarcts have been traditionally summarized as global metrics, independent of location or structural consequence. We sought to determine if infarct location and related structural connectivity changes were associated with postoperative delirium after SAVR.

METHODS

A secondary analysis of a randomized multicenter SAVR trial of embolic protection devices (NCT02389894) was conducted, excluding participants with clinical stroke or incomplete neuroimaging (N = 298; 39% female, 7% non-White, 74 ± 7 years). Delirium during in-hospital recovery was serially screened using the Confusion Assessment Method. Parcellation and tractography atlas-based neuroimaging methods were used to determine infarct locations and cortical connectivity effects. Mixed-effect, zero-inflated gaussian modeling analyses, accounting for brain region-specific infarct characteristics, were conducted to examine for differences within and between groups by delirium status and perioperative neuroprotection device strategy.

RESULTS

23.5% participants experienced postoperative delirium. Delirium was associated with significantly increased lesion volumes in the right cerebellum and temporal lobe white matter, while diffusion weighted imaging infarct-related structural disconnection (DWI-ISD) was observed in frontal and temporal lobe regions (p-FDR < 0.05). Fewer brain regions demonstrated DWI-ISD loss in the suction-based neuroprotection device group, relative to filtration-based device or standard aortic cannula.

INTERPRETATION

Structural disconnection from acute infarcts was greater in patients who experienced postoperative delirium, suggesting that the impact from covert perioperative infarcts may not be as clinically "silent" as commonly assumed.

Role of Intraoperative Neuromonitoring to Predict Postoperative Delirium in Cardiovascular Surgery

OBJECTIVE

Postoperative delirium (POD) can occur in up to 50% of older patients undergoing cardiovascular surgery, resulting in hospitalization and significant morbidity and mortality. This study aimed to determine whether intraoperative neurophysiologic monitoring (IONM) modalities can be used to predict delirium in patients undergoing cardiovascular surgery.

DESIGN

Adult patients undergoing cardiovascular surgery with IONM between 2019 and 2021 were reviewed retrospectively. Delirium was assessed multiple times using the Intensive Care Delirium Screening Checklist (ICDSC). Patients with an ICDSC score ≥4 were considered to have POD. Significant IONM changes were evaluated based on a visual review of electroencephalography (EEG) and somatosensory evoked potentials data and documentation of significant changes during surgery.

SETTING

University of Pittsburgh Medical Center hospitals.

PARTICIPANTS

Patients 18 years old and older undergoing cardiovascular surgery with IONM monitoring.

MEASUREMENTS AND MAIN RESULTS

Of the 578 patients undergoing cardiovascular surgery with IONM, 126 had POD (21.8%). Significant IONM changes were noted in 134 patients, of whom 49 patients had delirium (36.6%). In contrast, 444 patients had no IONM changes during surgery, of whom 77 (17.3%) patients had POD. Upon multivariate analysis, IONM changes were associated with POD (odds ratio 2.12; 95% CI 1.31-3.44; p < 0.001). Additionally, baseline EEG abnormalities were associated with POD (p = 0.002).

CONCLUSION

Significant IONM changes are associated with an increased risk of POD in patients undergoing cardiovascular surgery. These findings offer a basis for future research and analysis of EEG and somatosensory evoked potential monitoring to predict, detect, and prevent POD.

Assessment of silent brain injury in patients undergoing elective percutaneous coronary intervention due to chronic total occlusion

Objective: Silent brain infarcts (SBI) are thromboembolic complications associated with cardiac surgery, diagnostic angiography, and percutaneous interventions. Serum neuron-specific enolase (NSE) is the proven biomarker for measuring neuronal damage. This study aimed to evaluate the incidence of SBI, defined as elevated NSE after coronary chronic total occlusion (CTO) intervention and elective coronary stenting. Design: The study population consisted of two patient groups: the CTO group included consecutive patients with coronary CTO intervention, and the control group consisted of patients who underwent elective coronary intervention. NSE blood levels were measured before and 12-18 h after the procedure. NSE blood levels of >20 ng/mL were considered SBI. Results: A total of 108 patients were included in the study. Of these, 55 (50.9%) had SBI after the procedure. The SBI rate was 59.7% in the CTO group and 39.1% in the control group. Patients with SBI were more likely to have diabetes mellitus, hyperlipidemia, higher HbA1c, higher total stent length, and longer procedural time. Multivariate logistic regression analysis showed that CTO procedure (odds ratio [OR]: 3.129; 95% confidence interval [CI]: 1.246-7.858; p < 0.015) and diabetes mellitus (OR: 2.93; 95% CI: 1.185-7.291; p < 0.020) are independent predictors of SBI. Conclusion: Our data suggest that SBI occurs more frequently after CTO intervention than after non-CTO intervention. Intervention complexity and patient clinical characteristics may explain the increased incidence.

Cerebral emboli detection and autonomous neuromonitoring using robotic transcranial Doppler with artificial intelligence for transcatheter aortic valve replacement with and without embolic protection devices: a pilot study

BACKGROUND

Periprocedural ischemic stroke remains a serious complication in patients undergoing transcatheter aortic valve replacement (TAVR). We used a novel robotic transcranial Doppler (TCD) system equipped with artificial intelligence (AI) for real-time continuous intraoperative neuromonitoring during TAVR to establish the safety and potential validity of this tool in detecting cerebral emboli, report the quantity and distribution of high intensity transient signals (HITS) with and without cerebral protection, and correlate HITS occurrence with various procedural steps.

METHODS

Consecutive patients undergoing TAVR procedures during which the robotic system was used between October 2021 and May 2022 were prospectively enrolled in this pilot study. The robotic TCD system included autonomous adjustment of the TCD probes and AI-assisted post-processing of HITS and other cerebral flow parameters. Basic demographics and procedural details were recorded. Continuous variables were analyzed by a two-sample Mann-Whitney t-test and categorical variables by a χ2 or Fisher test.

RESULTS

Thirty-one patients were prospectively enrolled (mean age 79.9±7.6 years; 16 men (51.6%)). Mean aortic valve stenotic area was 0.7 cm2 and mean aortic-ventricular gradient was 43 mmHg (IQR 31.5-50 mmHg). Cerebral protection was used in 16 cases (51.6%). Significantly fewer emboli were observed in the protection group than in the non-protection group (mean 470.38 vs 693.33; p=0.01). Emboli counts during valve positioning and implantation were significantly different in the protection and non-protection groups (mean 249.92 and 387.5, respectively; p=0.01). One (4%) transient ischemic attack occurred post-procedurally in the non-protection group.

CONCLUSION

We describe a novel real-time intraoperative neuromonitoring tool used in patients undergoing TAVR. Significantly fewer HITS were detected with protection. Valve positioning-implantation was the most significant stage for intraprocedural HITS.

Neurologic complications after cardiopulmonary bypass - A narrative review

Neurologic complications, associated with cardiac surgery and cardiopulmonary bypass (CPB) in adults, are common and can be devastating in some cases. This comprehensive review will not only consider the broad categories of stroke and neurocognitive dysfunction, but it also summarises other neurological complications associated with CPB, and it provides an update about risks, prevention and treatment. Where appropriate, we consider the impact of off-pump techniques upon our understanding of the contribution of CPB to adverse outcomes.

Efficacy and safety of carbon dioxide insufflation for brain protection for patients undergoing planned left-sided open heart valve surgery: protocol for a multicentre, placebo-controlled, blinded, randomised controlled trial (the CO2 Study)

INTRODUCTION

Brain injury is common following open heart valve surgery. Carbon dioxide insufflation (CDI) has been proposed to reduce the incidence of brain injury by reducing the number of air microemboli entering the bloodstream in surgery. The CO2 Study will evaluate the efficacy and safety of CDI in patients undergoing planned left-sided open heart valve surgery.

METHODS AND ANALYSIS

The CO2 Study is a multicentre, blinded, placebo-controlled, randomised controlled trial. Seven-hundred and four patients aged 50 years and over undergoing planned left-sided heart valve surgery will be recruited to the study, from at least eight UK National Health Service hospitals, and randomised in a 1:1 ratio to receive CDI or medical air insufflation (placebo) in addition to standard de-airing. Insufflation will be delivered at a flow rate of 5 L/min from before the initiation of cardiopulmonary bypass until 10 min after cardiopulmonary bypass weaning. Participants will be followed up until 3 months post-surgery. The primary outcome is acute ischaemic brain injury within 10 days post-surgery based on new brain lesions identified with diffusion-weighted MRI or clinical evidence of permanent brain injury according to the current definition of stroke.

ETHICS AND DISSEMINATION

The study was approved by the East Midlands-Nottingham 2 Research Ethics Committee in June 2020 and the Medicines and Healthcare products Regulatory Agency in May 2020. All participants will provide written informed consent prior to undertaking any study assessments. Consent will be obtained by the principal investigator or a delegated member of the research team who has been trained in the study and undergone Good Clinical Practice training. Results will be disseminated through peer-reviewed publications and presentations at national and international meetings. Study participants will be informed of results through study notifications and patient organisations.

TRIAL REGISTRATION NUMBER

ISRCTN30671536.

Mechanisms and Clinical Manifestations of Cognitive Decline in Atrial Fibrillation Patients: Potential Implications for Preventing Dementia

Atrial fibrillation (AF) patients face an approximate 1.5-fold increased risk of cognitive decline compared with the general population. Among poststroke AF patients, the risk of cognitive decline is even higher with an estimated threefold increase. This article provides a narrative review on the current evidence and highlights gaps in knowledge and areas for future research. Although earlier studies hypothesized that the association between AF and cognitive decline is mainly a consequence of previous ischemic strokes, more recent evidence also suggests such an association in AF patients without a history of clinical stroke. Because AF and cognitive decline mainly occur among elderly individuals, it is not surprising that both entities share multiple risk factors. In addition to clinically overt ischemic strokes, silent brain infarcts and other brain injury are likely mechanisms for the increased risk of cognitive decline among AF patients. Oral anticoagulation for stroke prevention in AF patients with additional stroke risk factors is one of the only proven therapies to prevent brain injury. Whether a broader use of oral anticoagulation, or more intense anticoagulation in some patients are beneficial in this context needs to be addressed in future studies. Although direct studies are lacking, it is reasonable to recommend optimal treatment of comorbidities and risk factors for the prevention of cognitive decline and dementia.

Acute Infarcts on Brain MRI Following Aortic Arch Repair With Circulatory Arrest: Insights From the ACE CardioLink-3 Randomized Trial

BACKGROUND

to investigate the frequency and distribution of new ischemic brain lesions detected by diffusion-weighted imaging on brain magnetic resonance imaging after aortic arch surgery.

METHODS

This preplanned secondary analysis of the randomized, controlled ACE (Aortic Surgery Cerebral Protection Evaluation) CardioLink-3 trial compared the safety and efficacy of innominate versus axillary artery cannulation during elective proximal aortic arch surgery. Participants underwent pre and postoperative magnetic resonance imaging. New ischemic lesions were defined as lesions visible on postoperative, but not preoperative diffusion weighted imaging.

RESULTS

Of the 111 trial participants, 102 had complete magnetic resonance imaging data. A total of 391 new ischemic lesions were observed on diffusion-weighted imaging in 71 (70%) patients. The average number of lesions in patients with ischemic lesion were 5.5±4.9 with comparable numbers in the right (2.9±2.0) and left (3.0±2.3) hemispheres (P=0.49). Half the new lesions were in the middle cerebral artery territory; 63% of the cohort had ischemic lesions in the anterior circulation, 49% in the posterior circulation, 42% in both, and 20% in watershed areas. A probability mask of all diffusion-weighted imaging lesions revealed that the cerebellum was commonly involved. More severe white matter hyperintensity on preoperative magnetic resonance imaging (odds ratio, 1.80 [95% CI, 1.10-2.95]; P=0.02) and lower nadir nasopharyngeal temperature during surgery (odds ratio per 1°C decrease, 1.15 [95% CI, 1.00-1.32]; P=0.05) were associated with the presentation of new ischemic lesion; older age (risk ratio per 1-year increase, 1.02 [95% CI, 1.00-1.04]; P=0.03) and lower nadir temperature (risk ratio per 1°C decrease, 1.06 [95% CI, 1.00-1.14]; P=0.06) were associated with greater number of lesions.

CONCLUSIONS

In patients who underwent elective proximal aortic arch surgery, new ischemic brain lesions were common, and predominantly involved the middle cerebral artery territory or cerebellum. Underlying small vessel disease, lower temperature nadir during surgery, and advanced age were risk factors for perioperative ischemic lesions.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02554032.

A comprehensive review of cerebral oximetry in cardiac surgery

BACKGROUND

Patients who undergo cardiac surgery are at increased risk of stroke, postoperative cognitive decline, and delirium. These neurocognitive complications have led to increased costs, intensive care unit stays, morbidity, and mortality. As a result, there is a significant push to mitigate any neurological complications in cardiac surgery patients. Near-infrared spectroscopy to measure regional cerebral oxygen saturations has gained consideration due to its noninvasive and user-friendly nature. Cerebral oximetry desaturations during cardiac surgery have been linked to an array of adverse clinical outcomes. However, the most effective intraoperative interventions to protect this vulnerable patient population have yet to be ascertained.

AIM OF STUDY

To provide a comprehensive summary of the intraoperative management for cerebral oximetry desaturations during cardiac surgery. The review highlights clinical outcomes from cerebral oximetry use to quantify the importance of identifying cerebral desaturations during cardiac surgery. The review then interrogates possible interventions for cerebral oximetry desaturations in an effort to determine which interventions are most efficacious and to enlighten possible areas for further research.

METHODS

A narrative review of randomized controlled trials, observational studies, and systematic reviews with metanalyses was performed through August 2021.

RESULTS

There is significant heterogeneity among patient populations for which cerebral oximetry monitoring has been studied in cardiac surgery. Further, the definition of a clinically significant cerebral desaturation and the assessment of neurocognitive outcomes varied substantially across studies. As a result, metanalysis is challenging and few conclusions can be drawn. Cerebral oximetry use during cardiac surgery has not been associated with improvements in neurocognitive outcomes, morbidity, or mortality to date. The evidence to support a particular intervention for an acute desaturation is equivocal.

CONCLUSIONS

Future research is needed to quantify a clinically significant cerebral desaturation and to determine which interventions for an acute desaturation effectively improve clinical outcomes.

Prediction of stroke reconvalescence after coronary bypass surgery indicated by CT scan parameters

BACKGROUND

Stroke in the postoperative time course after heart surgery remains a serious risk. Cranial computer tomography (CCT) is the first line option to detect severe intracranial damage. However, only few data are available to predict neurological outcome. Using visual rating scales (VRSs), this study addresses reliability and effectivity to indicate neurological status and likelyhood of improvement.

METHODS

In a single-center retrospective evaluation, 3719 patients underwent coronary bypass surgery. Because of a delayed recovery phase and neurologic deficits after cardiac surgery 109 patients had a cranial CT scan in the early postoperative period. The incidence of clinically relevant findings within the imaging was rated by an experienced neuroradiologist using two VRS, that is, the age-related white matter changes (ARWMCs) and the Mendes-Ribeiro visual rating scale (MRVRS). Both are computer-assisted measurement schemes to detect stroke-related intracranial damage. Follow-up was investigated with regard to clinical outcome and patient-related risk profiles.

RESULTS

Of 109 patients with postoperative cranial CT scans due to prolonged recovery phases or proven neurological damage 44.5% had one cerebral defect in CCT imaging scans only. The others showed multiple defects. During hospital stay, 92.3% experienced neurological improvement exposing reduced ARWMC, while 7.1% had no improvement and correlating high scores. Of both scales, the ARWMC-VRS demonstrated superior accuracy and discrimination. The preoperative ejection fraction (EF), arteriosclerotic degeneration of carotid arteries, and reduced glomerular filtration rate were found to have a high correlation (r = 0.0005) with the latter group. In-hospital mortality of this cohort was 8.18%.

CONCLUSION

Both the ARWMC and MRVRS were found to be appropriate. They reliably discriminate the groups of stroke patients after coronary artery bypass grafting (CABG)  in the analysis of CCT images. When applied at the onset of neurological symptoms both scales are able to predict neurological reconvalescence upon hospital dismission. The ARWMC scale appeared superior as it demonstrated better accuracy and discrimination. The use of both VRS in patients with suspected stroke after CABG surgery can give insightful information toward a progression of neurological dysfunction or postoperative improvement.

Silent Brain Infarction, Delirium, and Cognition in Three Invasive Cardiovascular Procedures: a Systematic Review

Silent brain infarctions (SBIs) are brain lesions noted on neuroimaging that are not associated with clinical symptoms. SBIs are associated with a number of vascular risk factors and are common following invasive cardiovascular procedures such as atrial fibrillation (AF) ablation, coronary artery bypass graft (CABG), and transcatheter aortic valve replacement (TAVR). Although not eliciting signs of clinical stroke, SBIs are associated with increased frailty, and motor and mood features. Less is known, however, about the relationship between SBI, cognition, and delirium following invasive cardiac procedures and most investigations into these relationships have been reported in large-scale epidemiological studies. In the current paper, we conducted a systematic review to evaluate evidence of a relationship between SBI, delirium, and cognitive decline following CABG, AF ablation, and TAVR. Twenty studies met inclusion criteria. In general, our review identified conflicting results for each cardiac procedure, with some studies suggesting a relationship between SBI, cognitive impairment, and delirium, whereas others showed no relationship between SBI, cognitive impairment, and delirium. Potential reasons for this discrepancy as well as suggestions for future research are discussed.

Association of Iatrogenic Infarcts With Clinical and Cognitive Outcomes in the Evaluating Neuroprotection in Aneurysm Coiling Therapy Trial

BACKGROUND AND OBJECTIVES

Small iatrogenic brain infarcts are often seen on diffusion-weighted MRI (DWI) following surgical or endovascular procedures, but there are few data on their clinical effects. We examined the association of iatrogenic infarcts with outcomes in the ENACT (Evaluating Neuroprotection in Aneurysm Coiling Therapy) randomized controlled trial of nerinetide in patients undergoing endovascular repair of intracranial aneurysms.

METHODS

In this post hoc analysis, we used multivariable models to evaluate the association of the presence and number of iatrogenic infarcts on DWI with neurologic impairment (NIH Stroke Scale [NIHSS]), functional status (modified Rankin Scale [mRS]), and cognitive and neuropsychiatric outcomes (30-minute test battery) at 1-4 days and 30 days postprocedure. We also related infarct number to a z score-derived composite outcome score using quantile regression.

RESULTS

Among 184 patients (median age 56 years [interquartile range (IQR) 50-64]), 124 (67.4%) had postprocedural DWI lesions (median 4, IQR 2-10.5). Nerinetide treatment was associated with fewer iatrogenic infarcts but no overall significant clinical treatment effects. Patients with infarcts had lower Mini-Mental State Examination (MMSE) scores at 2-4 days (median 28 vs 29, adjusted coefficient [acoef] -1.11, 95% CI -1.88 to -0.34, p = 0.005). Higher lesion counts were associated with worse day 1 NIHSS (adjusted odds ratio for NIHSS ≥1: 1.07, 1.02-1.12, p = 0.009), day 2-4 mRS (adjusted common odds ratio [acOR] 1.05, 1.01-1.09, p = 0.005), and day 2-4 MMSE (acoef -0.07, -0.13 to -0.003, p = 0.040) scores. At 30 days, infarct number remained associated with worse mRS (acOR 1.04, 1.01-1.07, p = 0.016) and Hopkins Verbal Learning Test (HVLT) delayed recall scores (acoef -0.21, -0.39 to -0.03, p = 0.020). Patients with infarcts trended towards lower 30-day Digit Symbol Substitution Test (DSST) scores (acoef -3.73, -7.36 to -0.10, p = 0.044). Higher lesion count was associated with worse composite outcome scores at both 1-4 days and 30 days (30-day acoef -0.12, 95% CI -0.21 to -0.03, p = 0.008). Among those with infarcts, day 1 NIHSS and day 2-4 mRS correlated with 30-day NIHSS, DSST, HVLT, and mRS scores, whereas day 2-4 MMSE correlated with 30-day NIHSS and DSST scores (Spearman ρ 0.47, p = 0.001).

DISCUSSION

Iatrogenic brain infarcts were associated with subtle differences in postprocedural (1-4 days) and 30-day outcomes on different measures in this middle-aged cohort, with earlier dysfunction correlating with later differences.

TRIAL REGISTRATION INFORMATION

Clinical trials registration NCT00728182.

Progress of research in postoperative cognitive dysfunction in cardiac surgery patients: A review article

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common complication of central nervous system in middle-aged and elderly patients after cardiac surgery. The purpose of this study was to review the progress in diagnosis, pathogenesis and risk factors and control strategy of POCD.

METHODS

A systematic literature search was conducted using Pubmed and EMBASE, using the Mesh terms and key words "POCD", "diagnostic criteria", "pathogenesis", "influencing factors" and "prevention strategies". Studies were retained for review after meeting strict inclusion criteria that included only prospective studies evaluating risk factors for POCD in patients who had elective cardiac surgery. Diagnosis of POCD needed to be confirmed using the Diagnostic and Statistical Manual of Montreal Cognitive Assessment (MoCA) Scale and other criteria.

RESULTS

"Twenty two articles were selected for inclusion. The incidence of POCD across the studies ranged from 9% to 54%. Multiple factors have been associated with the pathogenesis and increased risk of POCD, including neuroinflammation, dysfunction of cholinergic system, abnormal protein function (β-amyloid), old age, anesthetic, surgical and other factors."

CONCLUSIONS

POCD is a common complication after cardiac surgery in elderly. The highest POCD incidence was observed after open aortic, TAVI and CABG surgery. Age, cognitive function, depression, CPB and anesthetic use are leading risk factors. Further research is needed in determining interventions that will be effective in preventing and treating POCD in cardiac surgical setting.

Neurocognitive, Quality of Life, and Behavioral Outcomes for Patients With Covert Stroke After Cardiac Surgery: Exploratory Analysis of Data From a Prospectively Randomized Trial

BACKGROUND

Asymptomatic brain ischemic injury detected with diffusion-weighted magnetic resonance imaging (DWI) is reported in more than one-half of patients after cardiac surgery. There are conflicting findings on whether DWI-detected covert stroke is associated with neurocognitive dysfunction after surgery, and it is unclear whether such ischemic injury affects quality of life or behavioral outcomes. The purpose of this study was to perform exploratory analysis on whether covert stroke after cardiac surgery is associated with delayed neurocognitive recovery 1 month after surgery, impaired quality of life, anxiety, or depression.

METHODS

Analysis of data collected in a prospectively randomized study in patients undergoing cardiac surgery testing whether basing mean arterial pressure (MAP) targets during cardiopulmonary bypass to be above the lower limit of cerebral autoregulation versus usual practices reduces the frequency of adverse neurological outcomes. A neuropsychological testing battery was administered before surgery and then 1 month later. Patients underwent brain magnetic resonance imaging (MRI) between postoperative days 3 and 5. The primary outcome was DWI-detected ischemic lesion; the primary end point was change from baseline in domain-specific neurocognitive Z scores 1 month after surgery. Secondary outcomes included a composite indicator of delayed neurocognitive recovery, quality of life measures, state and trait anxiety, and Beck Depression Inventory scores.

RESULTS

Of the 164 patients with postoperative MRI data, clinical stroke occurred in 10 patients. Of the remaining 154 patients, 85 (55.2%) had a covert stroke. There were no statistically significant differences for patients with or without covert stroke in the change from baseline in Z scores in any of the cognitive domains tested adjusted for sex, baseline cognitive score, and randomization treatment arm. The frequency of delayed neurocognitive recovery (no covert stroke, 15.1%; covert stroke, 17.6%; P = .392), self-reported quality of life measurements, anxiety rating, or depression scores were not different between those with or without DWI ischemic injury.

CONCLUSIONS

More than one-half of patients undergoing cardiac surgery demonstrated covert stroke. In this exploratory analysis, covert stroke was not found to be significantly associated with neurocognitive dysfunction 1 month after surgery; evidence of impaired quality of life, anxiety, or depression, albeit a type II error, cannot be excluded.

Perfusion strategy using axillary or femoral cannulation for minimally invasive cardiac surgery: experience in 270 patients with computed tomography-based criteria

OBJECTIVES

In patients with atherosclerotic disease, minimally invasive cardiac surgery using retrograde perfusion for cardiopulmonary bypass via femoral cannulation (FC) carries a higher risk of brain embolization compared with antegrade perfusion. However, guidelines for selecting antegrade versus retrograde perfusion do not exist. We developed a computed tomography (CT)-based perfusion strategy and assessed outcomes.

METHODS

We studied 270 minimally invasive cardiac surgery patients, aged 68 ± 13, 124 female, body surface area 1.6 ± 0.2 m2. Antegrade perfusion using axillary cannulation (AC) was selected if any of the following preoperative enhanced CT scan criteria were satisfied anywhere in the aorta or iliac arteries: thrombosis thickness >3 mm, thrombosis >one-third of the total circumference and calcification present in the total circumference. FC was selected otherwise. Asymptomatic brain injury was assessed by diffusion-weighted magnetic resonance imaging.

RESULTS

AC and FC were selected in 95 (35%) and 175 patients, respectively. AC patients were 10 years older (P < 0.001) and had higher EuroSCORE II (2.7 ± 3.4 vs 1.7 ± 1.9, P = 0.002). The median cardiopulmonary time and cross-clamp times were not significantly different. No patients died in hospital. There was no immediate stroke in either group during 48 h after surgery. Asymptomatic brain injury was detected in 25 (26%) and 27 (15%) AC and FC patients, respectively, P = 0.03.

CONCLUSIONS

We believe our CT-based perfusion strategy using AC or FC minimized brain embolic rates. AC can be a good alternative to prevent brain embolization for minimally invasive cardiac surgery patients with advanced atherosclerotic disease.

The Anaortic Technique with Bilateral Internal Thoracic Artery Grafting - Filling the Gap in Coronary Artery Bypass Surgery

Coronary artery bypass grafting (CABG) has consolidated its role as the most effective procedure for treating patients with advanced atherosclerotic coronary artery disease, reducing the long-term risk of myocardial infarction and death compared to other therapies and relieving angina. Despite the recognized benefits afforded by surgical myocardial revascularization, a subset of higher-risk patients bears a more elevated risk of perioperative stroke. Stroke remains the drawback of conventional CABG and has been strongly linked to aortic manipulation (cannulation, cross-clamping, and side-biting clamping for the performance of proximal aortic anastomoses) and the use of cardiopulmonary bypass. Adoption of off-pump CABG (OPCAB) is demonstrated to lower the risk of perioperative stroke, as well as reducing the risk of short-term mortality, renal failure, atrial fibrillation, bleeding, and length of intensive care unit stay. However, increased risk persists owing to the need for the tangential ascending aorta clamping to construct the proximal anastomosis. The concept of anaortic (aorta no-touch) OPCAB (anOPCAB) stems from eliminating ascending aorta manipulation, virtually abolishing the risk of embolism caused by aortic wall debris into the brain circulation. The adoption of anOPCAB has been shown to further decrease the risk of postoperative stroke, especially in higher-risk patients, entailing a step forward and a refinement of outcomes provided by the primeval OPCAB technique. Therefore, anOPCAB has been the recommended technique in patients with cerebrovascular disease and/or calcification or atheromatous plaque in the ascending aorta and should be preferred in patients with high-risk factors for neurological damage and stroke.

Cerebral microemboli in mini-sternotomy compared to mini- thoracotomy for aortic valve replacement: a cross sectional cohort study

Background

Recently adopted mini-thoracotomy approach for surgical aortic valve replacement has shown benefits such as reduced pain and shorter recovery, compared to more conventional mini-sternotomy access. However, whether limited exposure of the heart and ascending aorta resulting from an incision in the second intercostal space may lead to increased intraoperative cerebral embolization and more prominent postoperative neurologic decline, remains inconclusive. The aim of our study was to assess potential neurological complications after two different minimal invasive surgical techniques for aortic valve replacement by measuring cerebral microembolic signal during surgery and by follow-up cognitive evaluation.

Methods

Trans-cranial Doppler was used for microembolic signal detection during aortic valve replacement performed via mini-sternotomy and mini-thoracotomy. Patients were evaluated using Addenbrooke’s Cognitive Examination Revised Test before and 30 days after surgical procedure.

Results

A total of 60 patients were recruited in the study. In 52 patients, transcranial Doppler was feasible. Of those, 25 underwent mini-sternotomy and 27 had mini-thoracotomy. There were no differences between groups with respect to sex, NYHA class distribution, Euroscore II or aortic valve area. Patients in mini-sternotomy group were younger (60.8 ± 14.4 vs.72 ± 5.84, p = 0.003), heavier (85.2 ± 12.4 vs.72.5 ± 12.9, p = 0.002) and had higher body surface area (1.98 ± 0.167 vs. 1.83 ± 0.178, p = 0.006). Surgery duration was longer in mini-sternotomy group compared to mini-thoracotomy (158 ± 24 vs. 134 ± 30 min, p < 0.001, respectively). There were no differences between groups in microembolic load, length of ICU or total hospital stay. Total microembolic signals count was correlated with cardiopulmonary bypass duration (5.64, 95%CI 0.677–10.60, p = 0.027). Addenbrooke’s Cognitive Examination Revised Test score decreased equivalently in both groups (p = 0.630) (MS: 85.2 ± 9.6 vs. 82.9 ± 11.4, p = 0.012; MT: 85.2 ± 9.6 vs. 81.3 ± 8.8, p = 0.001).

Conclusion

There is no difference in microembolic load between the groups. Total intraoperative microembolic signals count was associated with cardiopulmonary bypass duration. Age, but not micorembolic signals load, was associated with postoperative neurologic decline.

Trial registry number

clinicaltrials.gov, NCT02697786 14.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01509-8.

Biomarkers of Cerebral Injury for Prediction of Postoperative Cognitive Dysfunction in Patients Undergoing Cardiac Surgery

OBJECTIVES

To assess the ability of the biomarkers neuron-specific enolase (NSE), tau, neurofilament light chain (NFL), and glial fibrillary acidic protein (GFAP) to predict postoperative cognitive dysfunction (POCD) at discharge in patients who underwent cardiac surgery.

DESIGN

Post hoc analyses (with tests being prespecified before data analyses) from a randomized clinical trial.

SETTING

Single-center study from a primary heart center in Denmark.

PARTICIPANTS

Adult patients undergoing elective or subacute on-pump coronary artery bypass grafting and/or aortic valve replacement.

INTERVENTIONS

Blood was collected before induction of anesthesia, after 24 hours, after 48 hours, and at discharge from the surgical ward. The International Study of Postoperative Cognitive Dysfunction test battery was applied to diagnose POCD at discharge and after three months. Linear mixed models of covariance were used to assess whether repeated measurements of biomarker levels were associated with POCD. Receiver operating characteristic (ROC) curves were applied to assess the predictive value of each biomarker measurement for POCD.

MEASUREMENTS AND MAIN RESULTS

A total of 168 patients had biomarkers measured at baseline, and 47 (28%) fulfilled the POCD criteria at discharge. Patients with POCD at discharge had significantly higher levels of tau (p = 0.02) and GFAP (p = 0.01) from baseline to discharge. The biomarker measurements achieving the highest area under the ROC curve for prediction of POCD at discharge were NFL measured at discharge (AUC, 0.64; 95% confidence interval [CI], 0.54-0.73), GFAP measured 48 hours after induction (AUC, 0.64; 95% CI, 0.55-0.73), and GFAP measured at discharge (AUC, 0.64; 95% CI, 0.54-0.74), corresponding to a moderate predictive ability.

CONCLUSIONS

Postoperative serum levels of tau and GFAP were elevated significantly in patients with POCD who underwent cardiac surgery at discharge; however, the biomarkers achieved only modest predictive abilities for POCD at discharge. Postoperative levels of NSE were not associated with POCD at discharge.

Incidence and Risk Factors for Silent Brain Infarction After On-Pump Cardiac Surgery: A Meta-analysis and Meta-regression of 29 Prospective Cohort Studies

BACKGROUND

Silent brain infarction (SBI) happens at a considerable rate after on-pump cardiac surgery. Though termed silent, SBI is related to unfavorable clinical outcomes including higher incidence of future stroke and neurocognitive impairment in the general population. The risk factors of SBI have not been fully identified in both individual studies and several meta-analyses addressing the topic. In this meta-analysis, we aimed to conduct meta-regression analysis for the first time to explore risk factors for SBI after on-pump cardiac surgery.

METHODS

This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Medline, Embase, Central, Web of Science, and Wiley databases were searched for relevant studies. Preoperative patient baseline characteristics and intraoperative surgical parameters were extracted from included studies. For meta-regression, a P value of less than 0.1 was considered statistically significant in both univariable and multivariable analyses.

RESULTS

Twenty-nine studies with 1478 patients were included in this meta-analysis. The summarized SBI rate after on-pump cardiac surgery was 37% (95% CI 0.27-0.47, P < 0.0001). Heterogeneity between studies was significant (I2 = 94.9%, P < 0.0001). In multivariable meta-regression, we found that age (coefficient 0.014, 95% CI 0.001-0.029, P = 0.043), diabetes (coefficient 0.006, 95% CI - 0.001 to 0.013, P = 0.075), and proportion of CABG (coefficient - 0.001, 95% CI - 0.003 to 0.0003, P = 0.096) were significantly associated with SBI incidence.

CONCLUSION

From the meta-regression, we concluded that advanced age and diabetes were related to increased SBI incidence after on-pump cardiac surgery, while CABG procedure alone was associated with less SBI onset. Studies with more accurate diagnoses of SBI are required to add more conclusive evidence to the field.

Absence of (sub-)acute cerebral events or lesions after electroporation ablation in the left-sided canine heart

BACKGROUND

Irreversible electroporation (IRE) is a nonthermal ablation modality. A 200-J application can create deep myocardial lesions, but gas bubbles are created at the ablation electrode. Cerebral effects of these bubbles are unknown.

OBJECTIVE

The purpose of this study was to investigate gas microemboli-induced brain lesions after IRE and radiofrequency (RF) ablation to the left side of the canine heart, using magnetic resonance imaging (MRI) and histopathology.

METHODS

In 11 canines, baseline cerebral MRI scans were performed. In 9 animals, after retrograde femoral artery access, 12 ± 4 200-J IRE applications were administered in the ascending aorta. In 2 animals, 30 minutes of irrigated 30-W RF ablation using 10-30g of contact force was applied in the left ventricle. At days 1 and 5 after ablation, MRI was repeated. The brain tissue then was histopathologically examined.

RESULTS

All ablations and follow-up were uneventful. Intracardiac echography confirmed gas bubble formation after each IRE application. Neurologic examination was normal. MRI scans were normal in all animals at day 1 and were normal in 10 of 11 animals at day 5. In 1 animal, a single <2-mm-diameter lesion in the right temporal region could not be excluded as a small infarct or early hemorrhagic site. Histopathologic analysis of the same region showed no pathologic changes. In all other animals, gross and microscopic pathology were normal.

CONCLUSION

MRI images alone or in combination with histologic follow-up did not reveal treatment-related embolic events. Gross and microscopic pathology did not reveal evidence of treatment-related embolic events. IRE seems to be a safe ablation modality for the brain.

Toward stroke-free coronary surgery: The role of the anaortic off-pump bypass technique

Surgical coronary revascularization remains the preferred strategy in a significant portion of patients with coronary artery disease due to superior long-term outcomes. However, there is a significant risk of perioperative neurologic injury that has influenced guideline recommendations. These complications occur in 1%-5% of patients, ranging from overt neurologic deficits with permanent disability, to subtle cerebral defects noted on neuroimaging that may result in slow cognitive and functional decline. The primary mechanism by which these events occur is thromboembolism from manipulation of the ascending aorta. This occurs during cardiopulmonary bypass, aortic cross-clamping, and partial occlusion clamping (side clamp). Elderly patients and patients with aortic atheroma are, therefore, at significantly increased risk. Initial surgical techniques addressed this by aggressively debriding or replacing the ascending aorta during coronary artery bypass grafting (CABG). Strategies then moved toward minimizing aortic manipulation through pump-assisted beating heart surgery and off-pump surgery with partial occlusion clamping or proximal anastomosis devices. Finally, anaortic off-pump CABG aims to avoid all manipulation of the ascending aorta through advanced off-pump grafting techniques combined with in situ and composite grafts. This has been demonstrated to result in the greatest reduction in risk. Establishing successful anaortic off-pump CABG programs requires subspecialization and focused interest groups dedicated to advancing CABG outcomes.

Associations between mean arterial pressure during cardiopulmonary bypass and biomarkers of cerebral injury in patients undergoing cardiac surgery: secondary results from a randomized controlled trial

OBJECTIVES

Cardiac surgery is associated with risk of cerebral injury and mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) is suggested to be associated with cerebral injury. The 'Perfusion Pressure Cerebral Infarcts' (PPCI) trial randomized patients undergoing coronary artery bypass grafting (CABG) and/or aortic valve replacement to a MAP of 40-50 or 70-80 mmHg during CPB and found no difference in clinical or imaging outcomes between the groups. We here present PPCI trial predefined secondary end points, consisting of biomarkers of brain injury.

METHODS

Blood was collected from PPCI trial patients at baseline, 24 and 48 h after induction of anaesthesia and at discharge from the surgical ward. Blood was analysed for neuron-specific enolase, tau, neurofilament light and the glial marker glial fibrillary acidic protein. Linear mixed models were used to analyse differences in biomarker value changes from baseline between the 2 MAP allocation groups.

RESULTS

A total of 193 (98%) patients were included. We found no differences in biomarker levels over time from baseline to discharge between the 2 MAP allocation groups (PNSE = 0.14, PTau = 0.46, PNFL = 0.21, PGFAP = 0.13) and the result did not change after adjustment for age, sex and type of surgery.

CONCLUSIONS

We found no significant differences in levels of biomarkers of neurological injury in patients undergoing elective or subacute CABG and/or aortic valve replacement randomized to either a target MAP of 40-50 mmHg or a target MAP of 70-80 mmHg during CBP.

A randomized trial comparing axillary versus innominate artery cannulation for aortic arch surgery

BACKGROUND

Cerebral protection remains the cornerstone of successful aortic surgery; however, there is no consensus as to the optimal strategy.

OBJECTIVE

To compare the safety and efficacy of innominate to axillary artery cannulation for delivering antegrade cerebral protection during proximal aortic arch surgery.

METHODS

This randomized controlled trial (The Aortic Surgery Cerebral Protection Evaluation CardioLink-3 Trial, ClinicalTrials.gov Identifier: NCT02554032), conducted across 6 Canadian centers between January 2015 and June 2018, allocated 111 individuals to innominate or axillary artery cannulation. The primary safety outcome was neuroprotection per the appearance of new severe ischemic lesions on the postoperative diffusion-weighted-magnetic resonance imaging. The primary efficacy outcome was the difference in total operative time. Secondary outcomes included 30-day all-cause mortality and postoperative stroke.

RESULTS

One hundred two individuals (mean age, 63 ± 11 years) were in the primary safety per-protocol analysis. Baseline characteristics between the groups were similar. New severe ischemic lesions occurred in 19 participants (38.8%) in the axillary versus 18 (34%) in the innominate group (P for noninferiority = .0009). Total operative times were comparable (median, 293 minutes; interquartile range, 222-411 minutes) for axillary versus (298 minutes; interquartile range, 231-368 minutes) for innominate (P for superiority = .47). Stroke/transient ischemic attack occurred in 4 (7.1%) participants in the axillary versus 2 (3.6%) in the innominate group (P = .43). Thirty-day mortality, seizures, delirium, and duration of mechanical ventilation were similar in both groups.

CONCLUSIONS

diffusion-weighted magnetic resonance imaging assessments indicate that antegrade cerebral protection with innominate cannulation is safe and affords similar neuroprotection to axillary cannulation during aortic surgery, although the burden of new neurological lesions is high in both groups.

Silent Brain Infarcts Following Cardiac Procedures: A Systematic Review and Meta-Analysis

Background

Silent brain infarcts (SBI) are increasingly being recognized as an important complication of cardiac procedures as well as a potential surrogate marker for studies on brain injury. The extent of subclinical brain injury is poorly defined.

Methods and Results

We conducted a systematic review and meta‐analysis utilizing studies of SBIs and focal neurologic deficits following cardiac procedures. Our final analysis included 42 studies with 49 separate intervention groups for a total of 2632 patients. The prevalence of SBIs following transcatheter aortic valve implantation was 0.71 (95% CI 0.64‐0.77); following aortic valve replacement 0.44 (95% CI 0.31‐0.57); in a mixed cardiothoracic surgery group 0.39 (95% CI 0.28‐0.49); coronary artery bypass graft 0.25 (95% CI 0.15‐0.35); percutaneous coronary intervention 0.14 (95% CI 0.10‐0.19); and off‐pump coronary artery bypass 0.14 (0.00‐0.58). The risk ratio of focal neurologic deficits to SBI in aortic valve replacement was 0.22 (95% CI 0.15‐0.32); in off‐pump coronary artery bypass 0.21 (95% CI 0.02‐2.04); with mixed cardiothoracic surgery 0.15 (95% CI 0.07‐0.33); coronary artery bypass graft 0.10 (95% CI 0.05‐0.18); transcatheter aortic valve implantation 0.10 (95% CI 0.07‐0.14); and percutaneous coronary intervention 0.06 (95% CI 0.03‐0.14). The mean number of SBIs per patient was significantly higher in the transcatheter aortic valve implantation group (4.58 ± 2.09) compared with both the aortic valve replacement group (2.16 ± 1.62, P=0.03) and the percutaneous coronary intervention group (1.88 ± 1.02, P=0.03).

Conclusions

SBIs are a very common complication following cardiac procedures, particularly those involving the aortic valve. The high frequency of SBIs compared with strokes highlights the importance of recording this surrogate measure in cardiac interventional studies. We suggest that further work is required to standardize reporting in order to facilitate the use of SBIs as a routine outcome measure.

[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.

Silent brain infarction after minimally invasive cardiac surgery with retrograde perfusion

BACKGROUND AND AIM

There is no report on silent brain infarction (SBI) after minimally invasive cardiac surgery (MICS) with retrograde perfusion. Thus, the current study aimed to investigate the incidence of SBI after MICS using magnetic resonance imaging (MRI).

METHODS

This study included 174 patients who underwent MICS with retrograde perfusion between July 2014 and July 2018. Preoperative computed tomography (CT) angiography was routinely performed and vascular pathology was evaluated for patient selection. Postoperative MRI was performed to investigate the occurrence of SBI.

RESULTS

Out of the total 174 patients, 26 (14.9%) presented with SBI. A total of 61 SBI lesions were found in the 26 patients; of these, 34 (56%) SBI lesions were in the right hemisphere and 27 (44%) in the left hemisphere. SBIs were primarily observed in the posterior cerebral artery territory. Multivariate analysis revealed aortic stenosis to be the only risk factor of SBI.

CONCLUSIONS

Retrograde perfusion via femoral cannulation may not increase the incidence of SBI in selected MICS patients based on preoperative CT findings.

Lack of Association Between Gaseous Microembolisms Assessed by a Single Detection Device and Cerebral Complications in Cardiac Surgery Patients

OBJECTIVE

To assess the association between total volume and number of gaseous microemboli (GME) in the cardiopulmonary bypass (CPB) circuit and the occurrence of new postoperative cerebral infarctions and postoperative cognitive dysfunction (POCD) in patients undergoing cardiac surgery.

DESIGN

Predefined subanalyses of the randomized controlled Perfusion Pressure Cerebral Infarcts (PPCI) trial.

SETTING

Primary heart center in a university hospital.

PARTICIPANTS

A total of 143 adult patients undergoing cardiac surgery with CPB.

INTERVENTIONS

Patients were allocated 1:1 to a low-target mean arterial pressure (MAP) of 40 to 50 mmHg or a high-target MAP of 70 to 80 mmHg during CPB with a fixed pump flow of 2.4 liters per minute per square meter body surface area plus 10% to 20%.

MEASUREMENTS AND MAIN RESULTS

The total volume and number of GME in the CPB circuit were assessed by the Bubble Counter Clinical 200® (GAMPT GmbH). New cerebral infarcts were identified by diffusion-weighted magnetic resonance imaging (DWI) 3 to 6 days after surgery. The median number of GME per patient was 8069 (range 1,523-204,095) with a median total volume of 1.2 μL (range 0.07-48 μL). A total of 66 (46%) patients had DWI detected cerebral infarcts postoperatively, and 36 (28%) patients had POCD after 7 days. The authors found no significant association between volume or number of GME with MAP target allocation, presence of cerebral infarction, or POCD.

CONCLUSIONS

The authors found no significant associations between volume or number of GME with the occurrence of cerebral infarction or cognitive dysfunction in cardiac surgery patients.

Incidence and Distribution of Cerebral Embolism After Cardiac Surgery According to the Systemic Perfusion Strategy - A Diffusion-Weighted Magnetic Resonance Imaging Study

BACKGROUND

Stroke is a major concern in minimally invasive cardiac surgery, so we investigated the incidence and risk factors of cerebral embolism according to the systemic perfusion strategy under thorough imaging assessment.Methods and Results:Between November 2011 and May 2015, 315 cardiac surgery patients who underwent preoperative computed tomography angiography (CTA) as a routine evaluation were enrolled. The incidence and distribution of cerebral embolism were analyzed with routine postoperative brain diffusion-weighted magnetic resonance imaging (DW-MRI) examination. Anterograde perfusion was used in 103 patients (group A), and retrograde perfusion was performed in 212 patients (group R). Operative deaths, incidence of clinical stroke (group A: 0%, group R: 0.5%, P=0.77), and rate of cerebral embolism (group A: 35.9%, group R: 26.4%, P=0.08) were comparable. The median number of new embolic lesions detected by MRI per patient (group A: 2, group R: 2, P=0.16), maximal diameter of the lesion (group A: 6.5 mm, group R: 6.0 mm, P=0.97), and anatomic distribution of the lesion were similar between groups. In the multivariate analysis, hypertension, emergency status, atherosclerosis grade 3 or 4 (intimal thickening >4 mm), and cardiopulmonary bypass time were independent risk factors for postoperative cerebral embolism, but retrograde perfusion was not.

CONCLUSIONS

According to the results of postoperative DW-MRI, retrograde perfusion itself might not increase the incidence of postoperative cerebral embolism in properly selected cardiac surgery patients undergoing routine preoperative CTA examination.

Recent advances in cryoballoon ablation for atrial fibrillation

Introduction: Pulmonary vein isolation (PVI), by catheter ablation, represents the current treatment for drug-resistant atrial fibrillation (AF). Nowadays cryoballoon (CB) is a recognized ablation method in patients with atrial fibrillation, mainly due to its ease of use, leading to reproducible and fast procedures. This novel single shot technology literally revolutionized the approach to AF ablation. Areas covered: The historical development of the cryoballoon, ablation techniques and new approaches beyond the ordinary PVI and complications are summarized here. Expert opinion: Although cryoballoon ablation has greatly standardized the approach to PVI a few critical points still need to be clarified scientifically in order to further uniform this procedure in cath labs worldwide. Duration and dosage of the cryoapplication is undoubtedly a topic of great interest.

Comparison of effects of propofol versus sevoflurane for patients undergoing cardiopulmonary bypass cardiac surgery

Objective

To compare the effects of propofol versus sevoflurane on the outcomes of patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).

Methods

A total of 110 patients undergoing cardiac surgery with CPB in our hospital from January 2015 to June 2017 were randomly divided into 2 groups (n=55): Group A, in which anesthesia was maintained with sevoflurane, and Group B, in which anesthesia was maintained with propofol. The MMSE score before and after operation, perioperative laboratory index, incidence of postoperative cognitive dysfunction (POCD) and incidence of adverse events between the two groups were compared.

Results

The MMSE score was significantly higher in Group B than in Group A after anesthesia (p<0.05). Serum levels of the brain injury markers neuron-specific enolase, S100β and matrix metalloproteinase 9 were significantly lower in Group B than in Group A (p<0.05). POCD incidence at 12 hour and 24 hour after operation was significantly lower in Group B than in Group A (p<0.05). There were no significant differences in the incidence of low cardiac output and thoracotomy bleeding between two groups.

Conclusion

Compared with sevoflurane, the use of propofol during cardiac surgery with CPB can efficiently improve postoperative cognitive function without increasing the risk of adverse reactions.

Domain-specific cognitive dysfunction after cardiac surgery. A secondary analysis of a randomized trial

BACKGROUND

Brain injury and cognitive dysfunction are serious complications after cardiac surgery. In the perfusion pressure cerebral infarcts (PPCI) trial, we allocated cardiac surgery patients to a mean arterial pressure of either 70-80 mm Hg (high-target) or 40-50 mm Hg (low-target) during cardiopulmonary bypass. In this secondary analysis, we aimed to assess potential differences in domain-specific patterns of cognitive deterioration between allocation groups and to investigate any associations of postoperative cognitive dysfunction (POCD) with diffusion-weighted magnetic resonance imaging (DWI)-detected brain lesions.

METHODS

Of the 197 patients randomized in the PPCI trial, 89 in the low-target group and 80 in the high-target group had complete DWI datasets, and 92 and 80 patients had complete data for an evaluation of cognitive function at discharge respectively. Cognitive function was assessed prior to surgery, at discharge and at 3 months. DWI was obtained at baseline and on postoperative days 3 to 6.

RESULTS

We found no statistically significant differences between the two groups when comparing the proportion of patients with a domain-specific deterioration over the pre-defined critical level in seven individual test variables at discharge. Significant deterioration was most common in tests thought to assess cognitive flexibility and interference susceptibility and least common in the memory test. POCD at discharge was more frequent in patients with DWI-positive brain lesions (OR adjusted for age and group allocation: 2.24 [95% CI 1.48-3.00], P = 0.036).

CONCLUSIONS

Domain-specific patterns of POCD were comparable between groups. A significant association was seen between DWI-positive brain lesions and POCD.

Preconditioning in the Rhesus Macaque Induces a Proteomic Signature Following Cerebral Ischemia that Is Associated with Neuroprotection

Each year, thousands of patients are at risk of cerebral ischemic injury, due to iatrogenic responses to surgical procedures. Prophylactic treatment of these patients as standard care could minimize potential neurological complications. We have shown that protection of brain tissue, in a non-human primate model of cerebral ischemic injury, is possible through pharmacological preconditioning using the immune activator D192935. We postulate that preconditioning with D192935 results in neuroprotective reprogramming that is evident in the brain following experimentally induced cerebral ischemia. We performed quantitative proteomic analysis of cerebral spinal fluid (CSF) collected post-stroke from our previously published efficacy study to determine whether CSF protein profiles correlated with induced protection. Four groups of animals were examined: naïve animals (no treatment or stroke); animals treated with vehicle prior to stroke; D192935 treated and stroked animals, further delineated into two groups, ones that were protected (small infarcts) and those that were not protected (large infarcts). We found that distinct protein clusters defined the protected and non-protected animal groups, with a 16-member cluster of proteins induced exclusively in D192935 protected animals. Seventy percent of the proteins induced in the protected animals have functions that would enhance neuroprotection and tissue repair, including several members associated with M2 macrophages, a macrophage phenotype shown to contribute to neuroprotection and repair during ischemic injury. These studies highlight the translational importance of CSF biomarkers in defining mechanism and monitoring responses to treatment in development of stroke therapeutics.

[Predictors of cognitive outcome in ventilated early rehabilitation patients]

BACKGROUND

After weaning failure, patients who are transferred from intensive care units to early rehabilitation centers (ERC) not only suffer from motor deficits but also from cognitive deficits. It is still uncertain which patient factors have an impact on cognitive outcome at the end of early rehabilitation.

OBJECTIVE

Investigation of predictors of cognitive performance for initially ventilated early rehabilitation patients.

METHODS

A total of 301 patients (mean age 68.3 ± 11.4 years, 67% male) were consecutively enrolled in an ERC for a prospective observational study between January 2014 and December 2015. To investigate influencing factors on cognitive outcome operationalized by the neuromental index (NMI), we collected sociodemographic data, parameters about the critical illness, comorbidities, weaning and decannulation as well as different functional scores at admission and discharge and carried out multivariate analyses by ANCOVA.

RESULTS

Of the patients 248 (82%) were successfully weaned, 155 (52%) decannulated and 75 patients (25%) died of whom 39 (13%) were under palliative treatment. For the survivors (n = 226) we could identify independent predictors of the NMI at discharge from the ERC in the final sex and age-adjusted statistical model: alertness and decannulation were positively associated with the NMI whereas hypoxia, cerebral infarction and traumatic brain injury had a negative impact on cognitive ability. The model justifies 57% of the variance of the NMI (R² = 0.568) and therefore has a high quality of explanation.

CONCLUSION

Because of increased risk of cognitive deficits at discharge of ERC, all patients who suffered from hypoxia, cerebral infarction or traumatic brain injury should be intensively treated by neuropsychologists. Since decannulation is also associated with positive cognitive outcome, a rapid decannulation procedure should also be an important therapeutic target, especially in alert patients.

Sonolysis in risk reduction of symptomatic and silent brain infarctions during coronary stenting (SONOREDUCE): Randomized, controlled trial

BACKGROUND

Silent brain infarcts can be detected on magnetic resonance imaging (MRI) in ~22% of patients after coronary angioplasty and stenting (CS). The effect of periprocedural sonolysis on the risk of new brain infarcts during CS was examined.

METHODS

Patients undergoing elective CS were allocated randomly to a bilateral sonolysis group (70 patients, 58 men; mean age, 59.9 years) or a control group (74 patients, 45 men; mean age, 65.5 years). Neurologic examination, cognitive function tests, and brain MRI were performed prior to intervention and at 24 h after CS. Neurologic examination and cognitive function tests were repeated at 30 days after CS.

RESULTS

No significant differences were observed in the number of patients with new infarcts (25.7 vs. 18.9%, P = 0.423), the number of lesions (1.3 ± 1.0 vs. 2.9 ± 5.3, P = 0.493), lesion volume (0.16 ± 0.34 vs. 0.28 ± 0.60 mL, P = 0.143), and the number of patients with new ischemic lesions in the insonated MCA territories (18.6vs. 17.6%, P = 0.958) between the sonolysis group and the control group. There were no cases of stroke, transient ischemic attack, myocardial infarction, or death in the two groups. Intracranial bleeding was reported only in 1 patient in the control group (0 vs. 1.4%, P = 0.888). Clock-drawing test scores at 30 days were significantly higher in the sonolysis group than in the control group (median 3.0 vs. 2.5, P = 0.031).

CONCLUSIONS

Sonolysis does not reduce the risk of new brain infarcts after CS. The effect of sonolysis on number and volume of ischemic lesions and cognitive function should be assessed in further studies.

Comparison of Frequency of Silent Cerebral Infarction After Coronary Angiography and Stenting With Transradial Versus Transfemoral Approaches

Silent cerebral infarction (SCI) can be seen after coronary procedures. We investigated whether vascular access sites have an impact on the risk of SCI. A total of 255 consecutive patients who underwent diagnostic or interventional coronary procedures through transfemoral (n = 126 patients) or transradial (n = 129 patients) approach were evaluated. Neuron-specific enolase (NSE) levels were studied before and 12 hours after the procedure. Elevation of greater than 12 ng/ml was considered as SCI. Patients were mainly men (60%) with a mean age of 62 years. SCI was observed in 74 of 255 patients (29%). It was significantly more prevalent among transradial group. Elevation of NSE was observed in 36% of transradial group (n = 47) and 21% of the transfemoral group (n = 27) (p = 0.008). Patients with SCI were more likely to have male sexuality, hyperlipidemia, history of smoking, and previous myocardial infarction. Multivariate analysis demonstrated that patients who underwent coronary procedures through transradial approach were 2.1 times more likely to have an SCI than patients with transfemoral approach (95% confidence interval [CI] 1.205 to 3.666; p = 0.008). Other independent predictors of NSE elevation were previous myocardial infarction (odds ratio 8.6; 95% CI 4.209 to 17.572; p <0.001) and smoking history (odds ratio 7.251; 95% CI 3.855 to 13.639; p <0.001). The present study suggests that transradial coronary procedures carry higher risk of SCI when compared with transfemoral route.