A human embryonic limb cell atlas resolved in space and time.

Human limbs emerge during the fourth post-conception week as mesenchymal buds, which develop into fully formed limbs over the subsequent months1. This process is orchestrated by numerous temporally and spatially restricted gene expression programmes, making congenital alterations in phenotype common2. Decades of work with model organisms have defined the fundamental mechanisms underlying vertebrate limb development, but an in-depth characterization of this process in humans has yet to be performed. Here we detail human embryonic limb development across space and time using single-cell and spatial transcriptomics. We demonstrate extensive diversification of cells from a few multipotent progenitors to myriad differentiated cell states, including several novel cell populations. We uncover two waves of human muscle development, each characterized by different cell states regulated by separate gene expression programmes, and identify musculin (MSC) as a key transcriptional repressor maintaining muscle stem cell identity. Through assembly of multiple anatomically continuous spatial transcriptomic samples using VisiumStitcher, we map cells across a sagittal section of a whole fetal hindlimb. We reveal a clear anatomical segregation between genes linked to brachydactyly and polysyndactyly, and uncover transcriptionally and spatially distinct populations of the mesenchyme in the autopod. Finally, we perform single-cell RNA sequencing on mouse embryonic limbs to facilitate cross-species developmental comparison, finding substantial homology between the two species.

Systematic assessment of long-read RNA-seq methods for transcript identification and quantification.

The Long-read RNA-Seq Genome Annotation Assessment Project Consortium was formed to evaluate the effectiveness of long-read approaches for transcriptome analysis. Using different protocols and sequencing platforms, the consortium generated over 427 million long-read sequences from complementary DNA and direct RNA datasets, encompassing human, mouse and manatee species. Developers utilized these data to address challenges in transcript isoform detection, quantification and de novo transcript detection. The study revealed that libraries with longer, more accurate sequences produce more accurate transcripts than those with increased read depth, whereas greater read depth improved quantification accuracy. In well-annotated genomes, tools based on reference sequences demonstrated the best performance. Incorporating additional orthogonal data and replicate samples is advised when aiming to detect rare and novel transcripts or using reference-free approaches. This collaborative study offers a benchmark for current practices and provides direction for future method development in transcriptome analysis.

Dynamic transformations of genome-wide epigenetic marking and transcriptional control establish T cell identity.

T cell development comprises a stepwise process of commitment from a multipotent precursor. To define molecular mechanisms controlling this progression, we probed five stages spanning the commitment process using RNA-seq and ChIP-seq to track genome-wide shifts in transcription, cohorts of active transcription factor genes, histone modifications at diverse classes of cis-regulatory elements, and binding repertoire of GATA-3 and PU.1, transcription factors with complementary roles in T cell development. The results highlight potential promoter-distal cis-regulatory elements in play and reveal both activation sites and diverse mechanisms of repression that silence genes used in alternative lineages. Histone marking is dynamic and reversible, and though permissive marks anticipate, repressive marks often lag behind changes in transcription. In vivo binding of PU.1 and GATA-3 relative to epigenetic marking reveals distinctive factor-specific rules for recruitment of these crucial transcription factors to different subsets of their potential sites, dependent on dose and developmental context.

High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection.

Recent multi-dimensional simulations suggest that high-entropy buoyant plumes help massive stars to explode1,2. Outwardly protruding iron (Fe)-rich fingers of gas in the galactic supernova remnant3,4 Cassiopeia A seem to match this picture. Detecting the signatures of specific elements synthesized in the high-entropy nuclear burning regime (that is, α-rich freeze out) would constitute strong substantiating evidence. Here we report observations of such elements-stable titanium (Ti) and chromium (Cr)-at a confidence level greater than 5 standard deviations in the shocked high-velocity Fe-rich ejecta of Cassiopeia A. We found that the observed Ti/Fe and Cr/Fe mass ratios require α-rich freeze out, providing evidence of the existence of the high-entropy ejecta plumes that boosted the shock wave at explosion. The metal composition of the plumes agrees well with predictions for strongly neutrino-processed proton-rich ejecta2,5,6. These results support the operation of the convective supernova engine via neutrino heating in the supernova that produced Cassiopeia A.

Spatiotemporal DNA methylome dynamics of the developing mouse fetus.

Cytosine DNA methylation is essential for mammalian development but understanding of its spatiotemporal distribution in the developing embryo remains limited1,2. Here, as part of the mouse Encyclopedia of DNA Elements (ENCODE) project, we profiled 168 methylomes from 12 mouse tissues or organs at 9 developmental stages from embryogenesis to adulthood. We identified 1,808,810 genomic regions that showed variations in CG methylation by comparing the methylomes of different tissues or organs from different developmental stages. These DNA elements predominantly lose CG methylation during fetal development, whereas the trend is reversed after birth. During late stages of fetal development, non-CG methylation accumulated within the bodies of key developmental transcription factor genes, coinciding with their transcriptional repression. Integration of genome-wide DNA methylation, histone modification and chromatin accessibility data enabled us to predict 461,141 putative developmental tissue-specific enhancers, the human orthologues of which were enriched for disease-associated genetic variants. These spatiotemporal epigenome maps provide a resource for studies of gene regulation during tissue or organ progression, and a starting point for investigating regulatory elements that are involved in human developmental disorders.

The changing mouse embryo transcriptome at whole tissue and single-cell resolution.

During mammalian embryogenesis, differential gene expression gradually builds the identity and complexity of each tissue and organ system1. Here we systematically quantified mouse polyA-RNA from day 10.5 of embryonic development to birth, sampling 17 tissues and organs. The resulting developmental transcriptome is globally structured by dynamic cytodifferentiation, body-axis and cell-proliferation gene sets that were further characterized by the transcription factor motif codes of their promoters. We decomposed the tissue-level transcriptome using single-cell RNA-seq (sequencing of RNA reverse transcribed into cDNA) and found that neurogenesis and haematopoiesis dominate at both the gene and cellular levels, jointly accounting for one-third of differential gene expression and more than 40% of identified cell types. By integrating promoter sequence motifs with companion ENCODE epigenomic profiles, we identified a prominent promoter de-repression mechanism in neuronal expression clusters that was attributable to known and novel repressors. Focusing on the developing limb, single-cell RNA data identified 25 candidate cell types that included progenitor and differentiating states with computationally inferred lineage relationships. We extracted cell-type transcription factor networks and complementary sets of candidate enhancer elements by using single-cell RNA-seq to decompose integrative cis-element (IDEAS) models that were derived from whole-tissue epigenome chromatin data. These ENCODE reference data, computed network components and IDEAS chromatin segmentations are companion resources to the matching epigenomic developmental matrix, and are available for researchers to further mine and integrate.

An atlas of dynamic chromatin landscapes in mouse fetal development.

The Encyclopedia of DNA Elements (ENCODE) project has established a genomic resource for mammalian development, profiling a diverse panel of mouse tissues at 8 developmental stages from 10.5 days after conception until birth, including transcriptomes, methylomes and chromatin states. Here we systematically examined the state and accessibility of chromatin in the developing mouse fetus. In total we performed 1,128 chromatin immunoprecipitation with sequencing (ChIP-seq) assays for histone modifications and 132 assay for transposase-accessible chromatin using sequencing (ATAC-seq) assays for chromatin accessibility across 72 distinct tissue-stages. We used integrative analysis to develop a unified set of chromatin state annotations, infer the identities of dynamic enhancers and key transcriptional regulators, and characterize the relationship between chromatin state and accessibility during developmental gene regulation. We also leveraged these data to link enhancers to putative target genes and demonstrate tissue-specific enrichments of sequence variants associated with disease in humans. The mouse ENCODE data sets provide a compendium of resources for biomedical researchers and achieve, to our knowledge, the most comprehensive view of chromatin dynamics during mammalian fetal development to date.

Author Correction: An atlas of dynamic chromatin landscapes in mouse fetal development.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Expanded encyclopaedias of DNA elements in the human and mouse genomes.

The human and mouse genomes contain instructions that specify RNAs and proteins and govern the timing, magnitude, and cellular context of their production. To better delineate these elements, phase III of the Encyclopedia of DNA Elements (ENCODE) Project has expanded analysis of the cell and tissue repertoires of RNA transcription, chromatin structure and modification, DNA methylation, chromatin looping, and occupancy by transcription factors and RNA-binding proteins. Here we summarize these efforts, which have produced 5,992 new experimental datasets, including systematic determinations across mouse fetal development. All data are available through the ENCODE data portal (https://www.encodeproject.org), including phase II ENCODE1 and Roadmap Epigenomics2 data. We have developed a registry of 926,535 human and 339,815 mouse candidate cis-regulatory elements, covering 7.9 and 3.4% of their respective genomes, by integrating selected datatypes associated with gene regulation, and constructed a web-based server (SCREEN; http://screen.encodeproject.org) to provide flexible, user-defined access to this resource. Collectively, the ENCODE data and registry provide an expansive resource for the scientific community to build a better understanding of the organization and function of the human and mouse genomes.

Evaluating the oral delivery of GalNAc-conjugated siRNAs in rodents and non-human primates.

Oral delivery is the most widely used and convenient route of administration of medicine. However, oral administration of hydrophilic macromolecules is commonly limited by low intestinal permeability and pre-systemic degradation in the gastrointestinal (GI) tract. Overcoming some of these challenges allowed emergence of oral dosage forms of peptide-based drugs in clinical settings. Antisense oligonucleotides (ASOs) have also been investigated for oral administration but despite the recent progress, the bioavailability remains low. Given the advancement with highly potent and durable trivalent N-acetylgalactosamine (GalNAc)-conjugated small interfering RNAs (siRNAs) via subcutaneous (s.c.) injection, we explored their activities after oral administration. We report robust RNA interference (RNAi) activity of orally administrated GalNAc-siRNAs co-formulated with permeation enhancers (PEs) in rodents and non-human primates (NHPs). The relative bioavailability calculated from NHP liver exposure was <2.0% despite minimal enzymatic degradation in the GI. To investigate the impact of oligonucleotide size on oral delivery, highly specific GalNAc-conjugated single-stranded oligonucleotides known as REVERSIRs with different lengths were employed and their activities for reversal of RNAi effect were monitored. Our data suggests that intestinal permeability is highly influenced by the size of oligonucleotides. Further improvements in the potency of siRNA and PE could make oral delivery of GalNAc-siRNAs as a practical solution.

Risk Factors for Stroke in Penetrating Cerebrovascular Injuries.

OBJECTIVE: Penetrating cerebrovascular injuries (PCVI) are associated with a high incidence of mortality and neurologic events. The optimal treatment strategy of PCVI, especially when damage control measures are required, remains controversial. The aim of this study is to describe the management of PCVI and patient outcomes at a level 1 trauma center where vascular injuries are predominantly managed by trauma surgeons. METHODS: An institutional trauma registry was queried for patients with PCVI from 2011-2021. Patients with common carotid artery (CCA), internal carotid artery (ICA), or vertebral artery (VA) injuries were included for analysis. The primary outcome was in-hospital stroke. The secondary outcomes were in-hospital mortality and in-hospital stroke or death. A subgroup analysis was completed of arterial repair (primary repair or interposition graft) vs ligation/embolization vs temporary intravascular shunting at the index procedure. RESULTS: 54 patients with PCVI were analyzed. Overall, the in-hospital stroke rate was 17% and in-hospital mortality was 26%. Twenty-one patients (39%) underwent arterial interventions for PCVI. Ten patients underwent arterial repair, 6 patients underwent ligation/embolization, and 5 patients underwent intravascular shunting as damage control strategy with a plan for delayed repair. The rate of in-hospital stroke was 30% after arterial repair, 0% after arterial ligation or embolization, and 80% after temporary intravascular shunting. There was a significant difference in the stroke rate between the three subgroups (P=.015). Of the 32 patients that that did not have an intervention to the CCA, ICA, or VA, 1 patient with ICA occlusion and 1 patient with CCA intimal injury developed in-hospital stroke. The mortality rate was 0% after arterial repair, 50% after ligation or embolization, and 60% after intravascular shunting. The rate of stroke or death was 30% in the arterial repair group, 50% in the ligation or embolization group, and 100% in the temporary intravascular shunting group. CONCLUSIONS: High rates of stroke and mortality were seen in patients requiring damage control after PCVI. In particular, temporary intravascular shunting was associated with a high incidence of in-hospital stroke and 100% rate of stroke or death. Further investigation is needed into the factors related to these finding and whether the use of temporary intravascular shunting in PCVI is an advisable strategy.

Quantifying EHR and Policy Factors Associated with the Gender Productivity Gap in Ambulatory, General Internal Medicine.

BACKGROUND: The gender gap in physician compensation has persisted for decades. Little is known about how differences in use of the electronic health record (EHR) may contribute. OBJECTIVE: To characterize how time on clinical activities, time on the EHR, and clinical productivity vary by physician gender and to identify factors associated with physician productivity. DESIGN, SETTING, AND PARTICIPANTS: This longitudinal study included general internal medicine physicians employed by a large ambulatory practice network in the Northeastern United States from August 2018 to June 2021. MAIN MEASURES: Monthly data on physician work relative value units (wRVUs), physician and practice characteristics, metrics of EHR use and note content, and temporal trend variables. KEY RESULTS: The analysis included 3227 physician-months of data for 108 physicians (44% women). Compared with men physicians, women physicians generated 23.8% fewer wRVUs per month, completed 22.1% fewer visits per month, spent 4.0 more minutes/visit and 8.72 more minutes on the EHR per hour worked (all p < 0.001), and typed or dictated 36.4% more note characters per note (p = 0.006). With multivariable adjustment for physician age, practice characteristics, EHR use, and temporal trends, physician gender was no longer associated with productivity (men 4.20 vs. women 3.88 wRVUs/hour, p = 0.31). Typing/dictating fewer characters per note, relying on greater teamwork to manage orders, and spending less time on documentation were associated with higher wRVUs/hour. The 2021 E/M code change was associated with higher wRVUs/hour for all physicians: 10% higher for men physicians and 18% higher for women physicians (p < 0.001 and p = 0.009, respectively). CONCLUSIONS: Increased team support, briefer documentation, and the 2021 E/M code change were associated with higher physician productivity. The E/M code change may have preferentially benefited women physicians by incentivizing time-intensive activities such as medical decision-making, preventive care discussion, and patient counseling that women physicians have historically spent more time performing.

Addressing Substance Use in the Adolescent Transplant Population.

Adolescence is a unique period of physical and psychosocial changes as youth transition, over many years, to adulthood. The psychosocial changes that accompany adolescence include emotional separation from parents, greater influence of peer groups, an interest in self-identification and autonomy, and increased risk-taking behaviors. Substance use is a common form of risk-taking behavior in the adolescent developmental stage. Alcohol, nicotine, and cannabis are the most common types of substances used in the United States. In the adolescent transplant population, rates of substance use appear to be at, or slightly below, their peer counterparts. Substance use can lead to deleterious health outcomes for adolescent transplant patients as a result of impaired decision-making, reduction in medication and clinic visit compliance, increases in mental health disorders, and risk for developing dependence and a substance use disorder. Given the close relationship that many pediatric transplant providers have with their patients and families, transplant care teams are in an excellent position to help their patients by addressing adolescent substance use. This narrative review describes how providers can use proactive standardized approaches to identify and intervene with substance use behavior.

Factors associated with 60-day readmission among inpatients with COVID-19 at 21 United States health systems.

Identifying patients at risk for readmission after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection could facilitate care planning and prevention. This retrospective cohort study of 60-day readmission included 105 543 COVID-19 patients at 21 US healthcare systems who were discharged alive between February 2020 and November 2021. Generalized linear mixed regression analyses tested predictors of 60-day readmission and severity. The all-cause readmission rate was 15% (95% confidence interval [CI] = 10%-21%), with 22% (95% CI = 18%-26%) of readmitted patients needing intensive care, and 6% (95% CI = 05%-07%) dying. Factors associated with readmission included male sex, government insurance, positive smoking history, co-morbidity burden, longer index admissions, and diagnoses at index admission (e.g., cancer, chronic kidney disease, and liver disease). Death and intensive care rates at readmission declined postvaccine availability. Receiving at least two COVID-19 vaccine doses, which were more common among older patients and those with comorbid conditions, was not independently associated with readmission but predicted a reduced risk of death at readmission. This retrospective cohort study identified factors associated with all-cause readmission for patients re-admitted to the same health system after hospitalization with SARS-CoV-2 infection. Patients who are male, who smoke, who have a higher comorbidity burden, and have government insurance may benefit from additional postacute care planning.

Demographic variations and time to initiation of adjunct treatment following surgical resection of anaplastic astrocytoma in the United States: a National Cancer Database analysis.

BACKGROUND AND AIMS: The aim of this study was to analyze the trends, demographic differences in the type and time to initiation (TTI) of adjunct treatment AT following surgery for anaplastic astrocytoma (AA). MATERIAL AND METHODS: The National Cancer Database (NCDB) was queried for patients diagnosed with AA from 2004 to 2016. Cox proportional hazards and modeling was used to determine factors influencing survival, including the impact of time to initiation (TTI) of adjuvant therapy. RESULTS: Overall, 5890 patients were identified from the database. The use of combined RT + CT temporally increased from 66.3% (2004-2007) to 79% (2014-2016), p < 0001. Patients more likely to receive no treatment following surgical resection included elderly (> 60 years old), hispanic patients, those with either no or government insurance, those living > 20 miles from the cancer facility, those treated at low volume centers (< 2 cases/year). AT was received following surgical resection within 0-4 weeks, 4.1-8 weeks, and > 8 weeks in 41%, 48%, and 3%, respectively. Compared to patients who received RT + CT, patients were likely to receive RT only as AT either at 4-8 weeks or > 8 weeks after the surgical procedure. Patients who received AT within 0-4 weeks had the 3-year OS of 46% compared to 56.7% for patients who received treatment at 4.1-8 weeks. CONCLUSION: We found significant variation in the type and timing of adjunct treatment following surgical resection of AA in the United States. A considerable number of patients (15%) received no AT following surgery.

Risk of developing glioblastoma following non-CNS primary cancer: a SEER analysis between 2000 and 2018.

BACKGROUND: Patients with a prior malignancy are at elevated risk of developing subsequent primary malignancies (SPMs). However, the risk of developing subsequent primary glioblastoma (SPGBM) in patients with a prior cancer history is poorly understood. METHODS: We used the Surveillance, Epidemiology, and End Results (SEER) database and identified patients diagnosed with non-CNS malignancy between 2000 and 2018. We calculated a modified standardized incidence ratio (M-SIR), defined as the ratio of the incidence of SPGBM among patients with initial non-CNS malignancy to the incidence of GBM in the general population, stratified by sex latency, and initial tumor location. RESULTS: Of the 5,326,172 patients diagnosed with a primary non-CNS malignancy, 3559 patients developed SPGBM (0.07%). Among patients with SPGBM, 2312 (65.0%) were men, compared to 2,706,933 (50.8%) men in the total primary non-CNS malignancy cohort. The median age at diagnosis of SPGBM was 65 years. The mean latency between a prior non-CNS malignancy and developing a SPGBM was 67.3 months (interquartile range [IQR] 27-100). Overall, patients with a primary non-CNS malignancy had a significantly elevated M-SIR (1.13, 95% CI 1.09-1.16), with a 13% increased incidence of SPGBM when compared to the incidence of developing GBM in the age-matched general population. When stratified by non-CNS tumor location, patients diagnosed with primary melanoma, lymphoma, prostate, breast, renal, or endocrine malignancies had a higher M-SIR (M-SIR ranges: 1.09-2.15). Patients with lung cancers (M-SIR 0.82, 95% CI 0.68-0.99), or stomach cancers (M-SIR 0.47, 95% CI 0.24-0.82) demonstrated a lower M-SIR. CONCLUSION: Patients with a history of prior non-CNS malignancy are at an overall increased risk of developing SPGBM relative to the incidence of developing GBM in the general population. However, the incidence of SPGBM after prior non-CNS malignancy varies by primary tumor location, with some non-CNS malignancies demonstrating either increased or decreased predisposition for SPGBM depending on tumor origin. These findings merit future investigation into whether these relationships represent treatment effects or a previously unknown shared predisposition for glioblastoma and non-CNS malignancy.

Smoking Status, Nicotine Medication, Vaccination, and COVID-19 Hospital Outcomes: Findings from the COVID EHR Cohort at the University of Wisconsin (CEC-UW) Study.

INTRODUCTION: Available evidence is mixed concerning associations between smoking status and COVID-19 clinical outcomes. Effects of nicotine replacement therapy (NRT) and vaccination status on COVID-19 outcomes in smokers are unknown. METHODS: Electronic health record data from 104 590 COVID-19 patients hospitalized February 1, 2020 to September 30, 2021 in 21 U.S. health systems were analyzed to assess associations of smoking status, in-hospital NRT prescription, and vaccination status with in-hospital death and ICU admission. RESULTS: Current (n = 7764) and never smokers (n = 57 454) did not differ on outcomes after adjustment for age, sex, race, ethnicity, insurance, body mass index, and comorbidities. Former (vs never) smokers (n = 33 101) had higher adjusted odds of death (aOR, 1.11; 95% CI, 1.06-1.17) and ICU admission (aOR, 1.07; 95% CI, 1.04-1.11). Among current smokers, NRT prescription was associated with reduced mortality (aOR, 0.64; 95% CI, 0.50-0.82). Vaccination effects were significantly moderated by smoking status; vaccination was more strongly associated with reduced mortality among current (aOR, 0.29; 95% CI, 0.16-0.66) and former smokers (aOR, 0.47; 95% CI, 0.39-0.57) than for never smokers (aOR, 0.67; 95% CI, 0.57, 0.79). Vaccination was associated with reduced ICU admission more strongly among former (aOR, 0.74; 95% CI, 0.66-0.83) than never smokers (aOR, 0.87; 95% CI, 0.79-0.97). CONCLUSIONS: Former but not current smokers hospitalized with COVID-19 are at higher risk for severe outcomes. SARS-CoV-2 vaccination is associated with better hospital outcomes in COVID-19 patients, especially current and former smokers. NRT during COVID-19 hospitalization may reduce mortality for current smokers. IMPLICATIONS: Prior findings regarding associations between smoking and severe COVID-19 disease outcomes have been inconsistent. This large cohort study suggests potential beneficial effects of nicotine replacement therapy on COVID-19 outcomes in current smokers and outsized benefits of SARS-CoV-2 vaccination in current and former smokers. Such findings may influence clinical practice and prevention efforts and motivate additional research that explores mechanisms for these effects.

The psychological and behavioural factors associated with laypeople initiating CPR for out-of-hospital cardiac arrest: a systematic review.

BACKGROUND: Prompt, effective CPR greatly increases the chances of survival in out-of-hospital c ardiac arrest. However, it is often not provided, even by people who have previously undertaken training. Psychological and behavioural factors are likely to be important in relation to CPR initiation by lay-people but have not yet been systematically identified. METHODS: Aim: to identify the psychological and behavioural factors associated with CPR initiation amongst lay-people. DESIGN: Systematic review Data sources: Cochrane Library, MEDLINE, EMBASE, CINAHL, PsycInfo and Google Scholar. STUDY ELIGIBILITY CRITERIA: Primary studies reporting psychological or behavioural factors and data on CPR initiation involving lay-people published (inception to 31 Dec 2021). STUDY APPRAISAL AND SYNTHESIS METHODS: Potential studies were screened independently by two reviewers. Study characteristics, psychological and behavioural factors associated with CPR initiation were extracted from included studies, categorised by study type and synthesised narratively. RESULTS: One hundred and five studies (150,820 participants) comprising various designs, populations and of mostly weak quality were identified. The strongest and most ecologically valid studies identified factors associated with CPR initiation: the overwhelming emotion of the situation, perceptions of capability, uncertainty about when CPR is appropriate, feeling unprepared and fear of doing harm. Current evidence comprises mainly atheoretical cross-sectional surveys using unvalidated measures with relatively little formal testing of relationships between proposed variables and CPR initiation. CONCLUSIONS: Preparing people to manage strong emotions and increasing their perceptions of capability are likely important foci for interventions aiming to increase CPR initiation. The literature in this area would benefit from more robust study designs. SYSTEMATIC REVIEW REGISTRATION: PROSPERO: CRD42018117438.

Risk Factors for Cerebral Hyperperfusion Syndrome following Carotid Revascularization.

BACKGROUND: Cerebral hyperperfusion syndrome (CHS) is a rare but known complication of carotid revascularization that can result in severe postoperative disability and death. CHS is a well-described sequela of carotid endarterectomy (CEA) and, more recently, of transfemoral carotid artery stenting (TFCAS), but its incidence after transcarotid artery revascularization (TCAR) has not been delineated. The aims of this study were to determine the impact of procedure type (CEA versus TCAR versus TFCAS) on the development of CHS as well as to identify perioperative risk factors associated with CHS. METHODS: The Society for Vascular Surgery Vascular Quality Initiative was queried for patients aged ≥18 years who underwent CEA, TCAR, or TFCAS from 2015-2021. Emergent procedures were excluded. The primary outcome was postoperative development of CHS, defined as the presence of postoperative seizures, intracerebral hemorrhage due to hyperperfusion, or both. Bivariate and multivariable logistic regression analyses were performed to identify factors associated with CHS. RESULTS: 156,003 procedures were included (72.7% CEA, 12.4% TCAR, and 14.9% TFCAS). The incidence of CHS after CEA, TCAR, and TFCAS were 0.15%, 0.18%, and 0.53%, respectively. There was no significant difference in risk of CHS after TFCAS compared to CEA (odds ratio [OR]: 1.21; 95% confidence interval [CI] 0.76-1.92; P = 0.416), nor was there a difference between TCAR and CEA (OR: 0.91; 95% CI 0.57-1.45; P = 0.691). Perioperative risk factors associated with an increased risk of CHS included previous history of transient ischemic attack or stroke (OR: 2.50; 95% CI 1.69-3.68; P < 0.0001), necessity for urgent intervention within 48 hr (OR: 2.03; 95% CI 1.43-2.89; P < 0.0001), treatment of a total occlusion (OR: 3.80; 95% CI 1.16-12.47; P = 0.028), and need for postoperative intravenous blood pressure medication (OR: 5.45; 95% CI 3.97-7.48; P < 0.0001). Age, preoperative hypertension, degree of ipsilateral stenosis less than or equal to 99%, and history of prior carotid procedures were not statistically associated with an increased risk of CHS. Discharging patients on an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker was associated with a decreased risk of developing CHS (OR: 0.47; 95% CI 0.34-0.65; P < 0.0001). CONCLUSIONS: Compared with CEA, TCAR and TFCAS were not statistically associated with an increased risk of postoperative CHS. Patients with a previous history of transient ischemic attack or stroke, who require urgent intervention or postoperative intravenous blood pressure medication, or who are treated for a total occlusion are at a higher risk of developing CHS. Using an angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker on discharge appears to be protective against CHS and should be considered for the highest risk patients.