SOFIA Aspiration System as first-line Technique (SOFAST): a prospective, multicenter study to assess the efficacy and safety of the 6 French SOFIA Flow Plus aspiration catheter for endovascular stroke thrombectomy.

BACKGROUND: Mechanical thrombectomy (MT) is the standard of care for acute ischemic stroke (AIS) patients with large vessel occlusion (LVO). The SOFAST study collected clinical evidence on the safety and efficacy of the 6 French SOFIA Flow Plus aspiration catheter (SOFIA 6F) when used as first-line treatment. METHODS: This was a prospective, multicenter investigation to assess the safety and efficacy of SOFIA 6F used for first-line aspiration. Anterior circulation LVO stroke patients were enrolled. The primary endpoint was the final modified Thrombolysis in Cerebral Infarction (mTICI)≥2b rate. Secondary endpoints included first-pass and first-line mTICI≥2b rates, times from arteriotomy to clot contact and mTICI≥2b, and 90-day modified Rankin Scale (mRS)≤2. First-line and final mTICI scores were adjudicated by an independent imaging core lab. Safety events were assessed by an independent clinical events adjudicator. RESULTS: A total of 108 patients were enrolled across 12 centers from July 2020 to June 2022. Median age was 67 years, median National Institutes of Health Stroke Scale (NIHSS) was 15.5, and 56.5% of patients received intravenous thrombolytics. At the end of the procedure, 97.2%, 85.2%, and 55.6% of patients achieved mTICI≥2b, ≥2c, and 3, respectively. With SOFIA 6F first-line aspiration, 87.0%, 79.6%, and 52.8% achieved mTICI≥2b, ≥2c, and 3, respectively. After the first pass, 75.0%, 70.4%, and 50.9% achieved mTICI≥2b, ≥2c, and 3, respectively. Median times from arteriotomy to clot contact and successful revascularization were 12 and 17 min, respectively. At 90 days, 66.7% of patients achieved mRS≤2. CONCLUSIONS: First-line aspiration with SOFIA 6F is safe and effective with high revascularization rates and short procedure times.

The MexTAg collaborative cross: host genetics affects asbestos related disease latency, but has little influence once tumours develop.

Objectives: This study combines two innovative mouse models in a major gene discovery project to assess the influence of host genetics on asbestos related disease (ARD). Conventional genetics studies provided evidence that some susceptibility to mesothelioma is genetic. However, the identification of host modifier genes, the roles they may play, and whether they contribute to disease susceptibility remain unknown. Here we report a study designed to rapidly identify genes associated with mesothelioma susceptibility by combining the Collaborative Cross (CC) resource with the well-characterised MexTAg mesothelioma mouse model. Methods: The CC is a powerful mouse resource that harnesses over 90% of common genetic variation in the mouse species, allowing rapid identification of genes mediating complex traits. MexTAg mice rapidly, uniformly, and predictably develop mesothelioma, but only after asbestos exposure. To assess the influence of host genetics on ARD, we crossed 72 genetically distinct CC mouse strains with MexTAg mice and exposed the resulting CC-MexTAg (CCMT) progeny to asbestos and monitored them for traits including overall survival, the time to ARD onset (latency), the time between ARD onset and euthanasia (disease progression) and ascites volume. We identified phenotype-specific modifier genes associated with these traits and we validated the role of human orthologues in asbestos-induced carcinogenesis using human mesothelioma datasets. Results: We generated 72 genetically distinct CCMT strains and exposed their progeny (2,562 in total) to asbestos. Reflecting the genetic diversity of the CC, there was considerable variation in overall survival and disease latency. Surprisingly, however, there was no variation in disease progression, demonstrating that host genetic factors do have a significant influence during disease latency but have a limited role once disease is established. Quantitative trait loci (QTL) affecting ARD survival/latency were identified on chromosomes 6, 12 and X. Of the 97-protein coding candidate modifier genes that spanned these QTL, eight genes (CPED1, ORS1, NDUFA1, HS1BP3, IL13RA1, LSM8, TES and TSPAN12) were found to significantly affect outcome in both CCMT and human mesothelioma datasets. Conclusion: Host genetic factors affect susceptibility to development of asbestos associated disease. However, following mesothelioma establishment, genetic variation in molecular or immunological mechanisms did not affect disease progression. Identification of multiple candidate modifier genes and their human homologues with known associations in other advanced stage or metastatic cancers highlights the complexity of ARD and may provide a pathway to identify novel therapeutic targets.

Reduce intraoperative albumin utilisation in cardiac surgical patients: a quality improvement initiative.

BACKGROUND: Albumin continues to be used routinely by cardiac anaesthesiologists perioperatively despite lack of evidence for improved outcomes. The Multicenter Perioperative Outcomes Group (MPOG) data ranked our institution as one of the highest intraoperative albumin users during cardiac surgery. Therefore, we designed a quality improvement project (QIP) to introduce a bundle of interventions to reduce intraoperative albumin use in cardiac surgical patients. METHODS: Our institutional MPOG data were used to analyse the FLUID-01-C measure that provides the number of adult cardiac surgery cases where albumin was administered intraoperatively by anaesthesiologists from 1 July 2019 to 30 June 2022. The QIP involved introduction of the following interventions: (1) education about appropriate albumin use and indications (January 2021), (2) email communications reinforced with OR teaching (March 2021), (3) removal of albumin from the standard pharmacy intraoperative medication trays (April 2021), (4) grand rounds presentation discussing the QIP and highlighting the interventions (May 2021) and (5) quarterly provider feedback (starting July 2021). Multivariable segmented regression models were used to assess the changes from preintervention to postintervention time period in albumin utilisation, and its total monthly cost. RESULTS: Among the 5767 cardiac surgery cases that met inclusion criteria over the 3-year study period, 16% of patients received albumin intraoperatively. The total number of cases that passed the metric (albumin administration was avoided), gradually increased as our interventions went into effect. Intraoperative albumin utilisation (beta=-101.1, 95% CI -145 to -56.7) and total monthly cost of albumin (beta=-7678, 95% CI -10712 to -4640) demonstrated significant decrease after starting the interventions. CONCLUSIONS: At a single academic cardiac surgery programme, implementation of a bundle of simple and low-cost interventions as part of a coordinated QIP were effective in significantly decreasing intraoperative use of albumin, which translated into considerable costs savings.

Essential right heart physiology for the perioperative practitioner POQI IX: current perspectives on the right heart in the perioperative period.

As patients continue to live longer from diseases that predispose them to right ventricular (RV) dysfunction or failure, many more patients will require surgery for acute or chronic health issues. Because RV dysfunction results in significant perioperative morbidity if not adequately assessed or managed, understanding appropriate assessment and treatments is important in preventing subsequent morbidity and mortality in the perioperative period. In light of the epidemiology of right heart disease, a working knowledge of right heart anatomy and physiology and an understanding of the implications of right-sided heart function for perioperative care are essential for perioperative practitioners. However, a significant knowledge gap exists concerning this topic. This manuscript is one part of a collection of papers from the PeriOperative Quality Initiative (POQI) IX Conference focusing on "Current Perspectives on the Right Heart in the Perioperative Period." This review aims to provide perioperative clinicians with an essential understanding of right heart physiology by answering five key questions on this topic and providing an explanation of seven fundamental concepts concerning right heart physiology.

A fluid biomarker reveals loss of TDP-43 splicing repression in presymptomatic ALS-FTD.

Although loss of TAR DNA-binding protein 43 kDa (TDP-43) splicing repression is well documented in postmortem tissues of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), whether this abnormality occurs during early-stage disease remains unresolved. Cryptic exon inclusion reflects loss of function of TDP-43, and thus detection of proteins containing cryptic exon-encoded neoepitopes in cerebrospinal fluid (CSF) or blood could reveal the earliest stages of TDP-43 dysregulation in patients. Here we use a newly characterized monoclonal antibody specific to a TDP-43-dependent cryptic epitope (encoded by the cryptic exon found in HDGFL2) to show that loss of TDP-43 splicing repression occurs in ALS-FTD, including in presymptomatic C9orf72 mutation carriers. Cryptic hepatoma-derived growth factor-like protein 2 (HDGFL2) accumulates in CSF at significantly higher levels in familial ALS-FTD and sporadic ALS compared with controls and is elevated earlier than neurofilament light and phosphorylated neurofilament heavy chain protein levels in familial disease. Cryptic HDGFL2 can also be detected in blood of individuals with ALS-FTD, including in presymptomatic C9orf72 mutation carriers, and accumulates at levels highly correlated with those in CSF. Our findings indicate that loss of TDP-43 cryptic splicing repression occurs early in disease progression, even presymptomatically, and that detection of the HDGFL2 cryptic neoepitope serves as a potential diagnostic biomarker for ALS, which should facilitate patient recruitment and measurement of target engagement in clinical trials.

Predictors for large vessel recanalization before stroke thrombectomy: the HALT score.

BACKGROUND: Large vessel recanalization (LVR) before endovascular therapy (EVT) for acute large vessel ischemic strokes is a poorly understood phenomenon. Better understanding of predictors for LVR is important for optimizing stroke triage and patient selection for bridging thrombolysis. METHODS: In this retrospective cohort study, consecutive patients presenting to a comprehensive stroke center for EVT treatment were identified from 2018 to 2022. Demographic information, clinical characteristics, intravenous thrombolysis (IVT) use, and LVR before EVT were recorded. Factors independently associated with different rates of LVR were identified, and a prediction model for LVR was constructed. RESULTS: 640 patients were identified. 57 (8.9%) patients had LVR before EVT. A minority (36.4%) of LVR patients had significant improvements in National Institutes of Health Stroke Scale. Independent predictors for LVR were identified and used to construct the 8-point HALT score: hyperlipidemia (1 point), atrial fibrillation (1 point), location of vascular occlusion (internal carotid: 0 points, M1: 1 point, M2: 2 points, vertebral/basilar: 3 points), and thrombolysis at least 1.5 hours before angiography (3 points). The HALT score had an area under the receiver-operating curve (AUC) of 0.85 (95% CI 0.81 to 0.90, P<0.001) for predicting LVR. LVR before EVT occurred in only 1 of 302 patients (0.3%) with low (0-2) HALT scores. CONCLUSIONS: IVT at least 1.5 hours before angiography, site of vascular occlusion, atrial fibrillation, and hyperlipidemia are independent predictors for LVR. The 8-point HALT score proposed in this study may be a valuable tool for predicting LVR before EVT.

Primary results from the CLEAR study of a novel stent retriever with drop zone technology.

BACKGROUND: Challenges to revascularization of large vessel occlusions (LVOs) persist. Current stent retrievers have limited effectiveness for removing organized thrombi. The NeVa device is a novel stent retriever designed to capture organized thrombi within the scaffold during retrieval. OBJECTIVE: To evaluate the safety and effectiveness of revascularization of acute LVOs with the NeVa device. METHODS: Prospective, international, multicenter, single-arm, Investigational Device Exemption study to evaluate the performance of the NeVa device in recanalizing LVOs including internal carotid artery, M1/M2 middle cerebral artery, and vertebrobasilar arteries, within 8 hours of onset. Primary endpoint was rate of expanded Treatment in Cerebral Ischemia (eTICI) score 2b-3 within 3 NeVa passes, tested for non-inferiority against a performance goal of 72% with a -10% margin. Additional endpoints included first pass success and 90-day modified Rankin Scale (mRS) score 0-2. Primary composite safety endpoint was 90-day mortality and/or 24-hour symptomatic intracranial hemorrhage (sICH). RESULTS: From April 2021 to April 2022, 139 subjects were enrolled at 25 centers. Median National Institutes of Health Stroke Scale (NIHSS) score was 16 (IQR 12-20). In the primary analysis population (n=107), eTICI 2b-3 within 3 NeVa passes occurred in 90.7% (97/107; non-inferiority P<0.0001; post hoc superiority P<0.0001). First pass eTICI 2b-3 was observed in 73.8% (79/107), with first pass eTICI 2b67-3 in 69.2% (74/107) and eTICI 2c-3 in 48.6% (52/107). Median number of passes was 1 (IQR 1-2). Final eTICI 2b-3 rate was 99.1% (106/107); final eTICI 2b67-3 rate was 91.6% (98/107); final eTICI 2c-3 rate was 72.9% (78/107). Good outcome (90-day mRS score 0-2) was seen in 65.1% (69/106). Mortality was 9.4% (13/138) with sICH in 5.0% (7/139). CONCLUSIONS: The NeVa device is highly effective and safe for revascularization of LVO strokes and demonstrates superior first pass success compared with a predicate performance goal. TRIAL REGISTRATION NUMBER: NCT04514562.

Management of Super-refractory Postoperative Lumbar Cerebrospinal Fluid Leak: A Case Report and Review of the Literature.

One well-documented risk of spinal surgery is cerebrospinal fluid (CSF) leak in the immediate postoperative period. While the majority of CSF leaks occur due to an obvious intraoperative dural tear, several reports have documented delayed CSF leakage from occult intraoperative dural tears. There is a paucity of published literature regarding the true incidence of dural tears in minimally invasive spinal surgery. Furthermore, the types of dural tears that require closure are poorly understood. According to the limited existing literature available, the recommended treatment of dural tears includes primary repair, subarachnoid drainage catheters, and blood patches. However, there are no distinct treatment guidelines between the different etiologies of CSF leakage. The most important aspect in the management of CSF leakage is prevention, including preoperative risk assessment and meticulous intraoperative manipulation. One emerging treatment strategy is to alter the pressure gradient in a manner that stops CSF leakage. This method is based on one of two mechanisms: direct suture or augmented closure with dural substitute material and either reducing the subarachnoid fluid pressure or increasing the epidural space pressure. Bed rest is a key element in the treatment of persistent CSF leaks, as it can reduce the lumbar CSF pressure, thereby preventing CSF leakage. We describe the challenging case of a persistent CSF leak despite multiple attempts at direct repair, as well as our management strategies. Understanding the proper positioning techniques to reduce leakage is crucial for proper management, and orthopedic surgeons, neurosurgeons, and neurointensivists may consider being more aggressive in treating persistent CSF leaks.

Targeted ASO-mediated Atp1a2 knockdown in astrocytes reduces SOD1 aggregation and accelerates disease onset in mutant SOD1 mice.

Astrocyte-specific ion pump α2-Na+/K+-ATPase plays a critical role in the pathogenesis of amyotrophic lateral sclerosis (ALS). Here, we test the effect of Atp1a2 mRNA-specific antisense oligonucleotides (ASOs) to induce α2-Na+/K+-ATPase knockdown in the widely used ALS animal model, SOD1*G93A mice. Two ASOs led to efficient Atp1a2 knockdown and significantly reduced SOD1 aggregation in vivo. Although Atp1a2 ASO-treated mice displayed no off-target or systemic toxicity, the ASO-treated mice exhibited an accelerated disease onset and shorter lifespan than control mice. Transcriptomics studies reveal downregulation of genes involved in oxidative response, metabolic pathways, trans-synaptic signaling, and upregulation of genes involved in glutamate receptor signaling and complement activation, suggesting a potential role for these molecular pathways in de-coupling SOD1 aggregation from survival in Atp1a2 ASO-treated mice. Together, these results reveal a role for α2-Na+/K+-ATPase in SOD1 aggregation and highlight the critical effect of temporal modulation of genetically validated therapeutic targets in neurodegenerative diseases.

Optimising multiplex immunofluorescence staining for characterising the tumour immune micro-environment.

Exploring the tumour microenvironment provides insight into the unique interaction between the host and tumour. Ultimately, its study improves understanding of how an individual mounts and achieves an anti-tumour immune response. In the context of colorectal cancer, immune biomarkers within the tumour microenvironment outperform traditional histopathological staging in predicting disease recurrence. Multiplex immunofluorescence enables simultaneous assessment of multiple markers to provide a highly accurate classification of immune cells and their spatial characterisation relative to tumour tissue. Further, automated slide staining provides staining consistency and reduces labour costs. Image acquisition using a non-spectral scanner allows more researchers to utilise multiplexed immunofluorescence for translational research. Herein we describe the optimisation process of conducting automated staining using a five-colour, tyramide signal amplification-based multiplex immunofluorescence panel. Using antibodies against CD3, CD8, CD103 and cytokeratin, the panel characterises T cell populations within human colorectal adenocarcinoma tissue. We provide an overview of primary antibody titration and the development of tyramide signal amplification immunofluorescence monoplex assays. We detail the processes of antibody stripping and the role of exogenous horseradish peroxidase inhibition to facilitate multiplexing. An account of determining the staining sequence and fluorophore assignment is provided. We describe image acquisition using a standard fluorescence microscope slide scanner and the management of spectral crosstalk using this system. Finally, we briefly document the digital image analysis required to characterise cells and determine their spatial distribution within the colorectal tumour microenvironment.

Natural Language Processing to Automatically Extract the Presence and Severity of Esophagitis in Notes of Patients Undergoing Radiotherapy.

PURPOSE: Radiotherapy (RT) toxicities can impair survival and quality of life, yet remain understudied. Real-world evidence holds potential to improve our understanding of toxicities, but toxicity information is often only in clinical notes. We developed natural language processing (NLP) models to identify the presence and severity of esophagitis from notes of patients treated with thoracic RT. METHODS: Our corpus consisted of a gold-labeled data set of 1,524 clinical notes from 124 patients with lung cancer treated with RT, manually annotated for Common Terminology Criteria for Adverse Events (CTCAE) v5.0 esophagitis grade, and a silver-labeled data set of 2,420 notes from 1,832 patients from whom toxicity grades had been collected as structured data during clinical care. We fine-tuned statistical and pretrained Bidirectional Encoder Representations from Transformers-based models for three esophagitis classification tasks: task 1, no esophagitis versus grade 1-3; task 2, grade ≤1 versus >1; and task 3, no esophagitis versus grade 1 versus grade 2-3. Transferability was tested on 345 notes from patients with esophageal cancer undergoing RT. RESULTS: Fine-tuning of PubMedBERT yielded the best performance. The best macro-F1 was 0.92, 0.82, and 0.74 for tasks 1, 2, and 3, respectively. Selecting the most informative note sections during fine-tuning improved macro-F1 by ≥2% for all tasks. Silver-labeled data improved the macro-F1 by ≥3% across all tasks. For the esophageal cancer notes, the best macro-F1 was 0.73, 0.74, and 0.65 for tasks 1, 2, and 3, respectively, without additional fine-tuning. CONCLUSION: To our knowledge, this is the first effort to automatically extract esophagitis toxicity severity according to CTCAE guidelines from clinical notes. This provides proof of concept for NLP-based automated detailed toxicity monitoring in expanded domains.

Natural Language Processing Methods to Empirically Explore Social Contexts and Needs in Cancer Patient Notes.

PURPOSE: There is an unmet need to empirically explore and understand drivers of cancer disparities, particularly social determinants of health. We explored natural language processing methods to automatically and empirically extract clinical documentation of social contexts and needs that may underlie disparities. METHODS: This was a retrospective analysis of 230,325 clinical notes from 5,285 patients treated with radiotherapy from 2007 to 2019. We compared linguistic features among White versus non-White, low-income insurance versus other insurance, and male versus female patients' notes. Log odds ratios with an informative Dirichlet prior were calculated to compare words over-represented in each group. A variational autoencoder topic model was applied, and topic probability was compared between groups. The presence of machine-learnable bias was explored by developing statistical and neural demographic group classifiers. RESULTS: Terms associated with varied social contexts and needs were identified for all demographic group comparisons. For example, notes of non-White and low-income insurance patients were over-represented with terms associated with housing and transportation, whereas notes of White and other insurance patients were over-represented with terms related to physical activity. Topic models identified a social history topic, and topic probability varied significantly between the demographic group comparisons. Classification models performed poorly at classifying notes of non-White and low-income insurance patients (F1 of 0.30 and 0.23, respectively). CONCLUSION: Exploration of linguistic differences in clinical notes between patients of different race/ethnicity, insurance status, and sex identified social contexts and needs in patients with cancer and revealed high-level differences in notes. Future work is needed to validate whether these findings may play a role in cancer disparities.

TREM2 inhibition triggers antitumor cell activity of myeloid cells in glioblastoma.

Triggering receptor expressed on myeloid cells 2 (TREM2) plays important roles in brain microglial function in neurodegenerative diseases, but the role of TREM2 in the GBM TME has not been examined. Here, we found that TREM2 is highly expressed in myeloid subsets, including macrophages and microglia in human and mouse GBM tumors and that high TREM2 expression correlates with poor prognosis in patients with GBM. TREM2 loss of function in human macrophages and mouse myeloid cells increased interferon-γ-induced immunoactivation, proinflammatory polarization, and tumoricidal capacity. In orthotopic mouse GBM models, mice with chronic and acute Trem2 loss of function exhibited decreased tumor growth and increased survival. Trem2 inhibition reprogrammed myeloid phenotypes and increased programmed cell death protein 1 (PD-1)+CD8+ T cells in the TME. Last, Trem2 deficiency enhanced the effectiveness of anti-PD-1 treatment, which may represent a therapeutic strategy for patients with GBM.

Pain management and opioid stewardship in adult cardiac surgery: Joint consensus report of the PeriOperative Quality Initiative and the Enhanced Recovery After Surgery Cardiac Society.

BACKGROUND: Opioid-based anesthesia and analgesia is a traditional component of perioperative care for the cardiac surgery patient. Growing enthusiasm for Enhanced Recovery Programs (ERPs) coupled with evidence of potential harm associated with high-dose opioids suggests that we reconsider the role of opioids in cardiac surgery. METHODS: An interdisciplinary North American panel of experts, using a structured appraisal of the literature and a modified Delphi method, derived consensus recommendations for optimal pain management and opioid stewardship for cardiac surgery patients. Individual recommendations are graded based on the strength and level of evidence. RESULTS: The panel addressed 4 main topics: the harms associated with historical opioid use, the benefits of more targeted opioid administration, the use of nonopioid medications and techniques, and patient and provider education. A key principle that emerged is that opioid stewardship should apply to all cardiac surgery patients, entailing judicious and targeted use of opioids to achieve optimal analgesia with the fewest potential side effects. The process resulted in the promulgation of 6 recommendations regarding pain management and opioid stewardship in cardiac surgery, focused on avoiding the use of high-dose opioids, as well as encouraging more widespread application of foundational aspects of ERPs, such as the use of multimodal nonopioid medications and regional anesthesia techniques, formal patient and provider education, and structured system-level opioid prescription practices. CONCLUSIONS: Based on the available literature and expert consensus, there is an opportunity to optimize anesthesia and analgesia for cardiac surgery patients. Although additional research is needed to establish specific strategies, core principles of pain management and opioid stewardship apply to the cardiac surgery population.

An End-to-End Natural Language Processing System for Automatically Extracting Radiation Therapy Events From Clinical Texts.

PURPOSE: Real-world evidence for radiation therapy (RT) is limited because it is often documented only in the clinical narrative. We developed a natural language processing system for automated extraction of detailed RT events from text to support clinical phenotyping. METHODS AND MATERIALS: A multi-institutional data set of 96 clinician notes, 129 North American Association of Central Cancer Registries cancer abstracts, and 270 RT prescriptions from HemOnc.org was used and divided into train, development, and test sets. Documents were annotated for RT events and associated properties: dose, fraction frequency, fraction number, date, treatment site, and boost. Named entity recognition models for properties were developed by fine-tuning BioClinicalBERT and RoBERTa transformer models. A multiclass RoBERTa-based relation extraction model was developed to link each dose mention with each property in the same event. Models were combined with symbolic rules to create a hybrid end-to-end pipeline for comprehensive RT event extraction. RESULTS: Named entity recognition models were evaluated on the held-out test set with F1 results of 0.96, 0.88, 0.94, 0.88, 0.67, and 0.94 for dose, fraction frequency, fraction number, date, treatment site, and boost, respectively. The relation model achieved an average F1 of 0.86 when the input was gold-labeled entities. The end-to-end system F1 result was 0.81. The end-to-end system performed best on North American Association of Central Cancer Registries abstracts (average F1 0.90), which are mostly copy-paste content from clinician notes. CONCLUSIONS: We developed methods and a hybrid end-to-end system for RT event extraction, which is the first natural language processing system for this task. This system provides proof-of-concept for real-world RT data collection for research and is promising for the potential of natural language processing methods to support clinical care.

Systematic reviews and consensus definitions for the Standardised Endpoints in Perioperative Medicine (StEP) initiative: mortality, morbidity, and organ failure.

BACKGROUND: Mortality, morbidity, and organ failure are important and common serious harms after surgery. However, there are many candidate measures to describe these outcome domains. Definitions of these measures are highly variable, and validity is often unclear. As part of the International Standardised Endpoints in Perioperative Medicine (StEP) initiative, this study aimed to derive a set of standardised and valid measures of mortality, morbidity, and organ failure for use in perioperative clinical trials. METHODS: Three domains of endpoints (mortality, morbidity, and organ failure) were explored through systematic literature review and a three-stage Delphi consensus process using methods consistently applied across the StEP initiative. Reliability, feasibility, and patient-centredness were assessed in round 3 of the consensus process. RESULTS: A high level of consensus was achieved for two mortality time points, 30-day and 1-yr mortality, and these two measures are recommended. No organ failure endpoints achieved threshold criteria for consensus recommendation. The Clavien-Dindo classification of complications achieved threshold criteria for consensus in round 2 of the Delphi process but did not achieve the threshold criteria in round 3 where it scored equivalently to the Post Operative Morbidity Survey. Clavien-Dindo therefore received conditional endorsement as the most widely used measure. No composite measures of organ failure achieved an acceptable level of consensus. CONCLUSIONS: Both 30-day and 1-yr mortality measures are recommended. No measure is recommended for organ failure. One measure (Clavien-Dindo) is conditionally endorsed for postoperative morbidity, but our findings suggest that no single endpoint offers a reliable and valid measure to describe perioperative morbidity that is not dependent on the quality of deli-vered care. Further refinement of current measures, or development of novel measures, of postoperative morbidity might improve consensus in this area.