Preoperative N-terminal pro-B-type natriuretic peptide and myocardial injury after stopping or continuing renin-angiotensin system inhibitors in noncardiac surgery: a prespecified analysis of a phase 2 randomised controlled multicentre trial

BACKGROUND

Patients with elevated preoperative plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP >100 pg ml-1) experience more complications after noncardiac surgery. Individuals prescribed renin-angiotensin system (RAS) inhibitors for cardiometabolic disease are at particular risk of perioperative myocardial injury and complications. We hypothesised that stopping RAS inhibitors before surgery increases the risk of perioperative myocardial injury, depending on preoperative risk stratified by plasma NT-proBNP concentrations.

METHODS

In a preplanned analysis of a phase 2a trial in six UK centres, patients ≥60 yr old undergoing elective noncardiac surgery were randomly assigned either to stop or continue RAS inhibitors before surgery. The pharmacokinetic profile of individual RAS inhibitors determined for how long they were stopped before surgery. The primary outcome, masked to investigators, clinicians, and patients, was myocardial injury (plasma high-sensitivity troponin-T ≥15 ng L-1 or a ≥5 ng L-1 increase, when preoperative high-sensitivity troponin-T ≥15 ng L-1) within 48 h after surgery. The co-exposures of interest were preoperative plasma NT-proBNP (< or >100 pg ml -1) and stopping or continuing RAS inhibitors.

RESULTS

Of 241 participants, 101 (41.9%; mean age 71 [7] yr; 48% females) had preoperative NT-proBNP >100 pg ml -1 (median 339 [160-833] pg ml-1), of whom 9/101 (8.9%) had a formal diagnosis of cardiac failure. Myocardial injury occurred in 63/101 (62.4%) subjects with NT-proBNP >100 pg ml-1, compared with 45/140 (32.1%) subjects with NT-proBNP <100 pg ml -1 {odds ratio (OR) 3.50 (95% confidence interval [CI] 2.05-5.99); P<0.0001}. For subjects with preoperative NT-proBNP <100 pg ml-1, 30/75 (40%) who stopped RAS inhibitors had myocardial injury, compared with 15/65 (23.1%) who continued RAS inhibitors (OR for stopping 2.22 [95% CI 1.06-4.65]; P=0.03). For preoperative NT-proBNP >100 pg ml-1, myocardial injury rates were similar regardless of stopping (62.2%) or continuing (62.5%) RAS inhibitors (OR for stopping 0.98 [95% CI 0.44-2.22]).

CONCLUSIONS

Stopping renin-angiotensin system inhibitors in lower-risk patients (preoperative NT-proBNP <100 pg ml -1) increased the likelihood of myocardial injury before noncardiac surgery.

Creatine supplementation for optimization of physical function in the patient at risk of functional disability: A systematic review and meta-analysis

BACKGROUND

The efficacy of creatine replacement through supplementation for the optimization of physical function in the population at risk of functional disability is unclear.

METHODS

We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane Library, and CINAHL from inception to November 2022. Studies included were randomized controlled trials (RCTs) comparing creatine supplementation with placebos in older adults and adults with chronic disease. The primary outcome was physical function measured by the sit-to-stand test after pooling data using random-effects modeling. We also performed a Bayesian meta-analysis to describe the treatment effect in probability terms. Secondary outcomes included other measures of physical function, muscle function, and body composition. The risk of bias was assessed using the Cochrane risk-of-bias tool.

RESULTS

We identified 33 RCTs, comprising 1076 participants. From six trials reporting the primary outcome, the pooled standardized mean difference (SMD) was 0.51 (95% confidence interval [CI]: 0.01-1.00; I2 = 62%; P = 0.04); using weakly informative priors, the posterior probability that creatine supplementation improves physical function was 66.7%. Upper-body muscle strength (SMD: 0.25; 95% CI: 0.06-0.44; I2 = 0%; P = 0.01), handgrip strength (SMD 0.23; 95% CI: 0.01-0.45; I2 = 0%; P = 0.04), and lean tissue mass (MD 1.08 kg; 95% CI: 0.77-1.38; I2 = 26%; P < 0.01) improved with creatine supplementation. The quality of evidence for all outcomes was low or very low because of a high risk of bias.

CONCLUSION

Creatine supplementation improves sit-to-stand performance, muscle function, and lean tissue mass. It is crucial to conduct high-quality prospective RCTs to confirm these hypotheses (PROSPERO number, CRD42023354929).

Discontinuation vs. continuation of renin-angiotensin system inhibition before non-cardiac surgery: the SPACE trial

BACKGROUND AND AIMS

Haemodynamic instability is associated with peri-operative myocardial injury, particularly in patients receiving renin-angiotensin system (RAS) inhibitors (angiotensin-converting-enzyme inhibitors/angiotensin II receptor blockers). Whether stopping RAS inhibitors to minimise hypotension, or continuing RAS inhibitors to avoid hypertension, reduces peri-operative myocardial injury remains unclear.

METHODS

From 31 July 2017 to 1 October 2021, patients aged ≥60 years undergoing elective non-cardiac surgery were randomly assigned to either discontinue or continue RAS inhibitors prescribed for existing medical conditions in six UK centres. Renin-angiotensin system inhibitors were withheld for different durations (2-3 days) before surgery, according to their pharmacokinetic profile. The primary outcome, masked to investigators, clinicians, and patients, was myocardial injury [plasma high-sensitivity troponin-T (hs-TnT) ≥ 15 ng/L within 48 h after surgery, or ≥5 ng/L increase when pre-operative hs-TnT ≥15 ng/L]. Pre-specified adverse haemodynamic events occurring within 48 h of surgery included acute hypertension (>180 mmHg) and hypotension requiring vasoactive therapy.

RESULTS

Two hundred and sixty-two participants were randomized to continue (n = 132) or stop (n = 130) RAS inhibitors. Myocardial injury occurred in 58 (48.3%) patients randomized to discontinue, compared with 50 (41.3%) patients who continued, RAS inhibitors [odds ratio (for continuing): 0.77; 95% confidence interval (CI) 0.45-1.31]. Hypertensive adverse events were more frequent when RAS inhibitors were stopped [16 (12.4%)], compared with 7 (5.3%) who continued RAS inhibitors [odds ratio (for continuing): 0.4; 95% CI 0.16-1.00]. Hypotension rates were similar when RAS inhibitors were stopped [12 (9.3%)] or continued [11 (8.4%)].

CONCLUSIONS

Discontinuing RAS inhibitors before non-cardiac surgery did not reduce myocardial injury, and could increase the risk of clinically significant acute hypertension. These findings require confirmation in future studies.

Clinical context and communication in shared decision-making about major surgery: Findings from a qualitative study with colorectal, orthopaedic and cardiac patients

Increasing numbers of older people undergo major surgery in the United Kingdom (UK), with many at high risk of complications due to age, co-morbidities or frailty. This article reports on a study of such patients and their clinicians engaged in shared decision-making. Shared decision-making is a collaborative approach that seeks to value and centre patients' preferences, potentially addressing asymmetries of knowledge and power between clinicians and patients by countering medical authority with greater patient empowerment. We studied shared decision-making practices in the context of major surgery by recruiting 16 patients contemplating either colorectal, cardiac or joint replacement surgery in the UK National Health Service (NHS). Over 18 months 2019-2020, we observed and video-recorded decision-making consultations, studied the organisational and clinical context for consultations, and interviewed patients and clinicians about their experiences of making decisions. Linguistic ethnography, the study of communication and interaction in context, guided us to analyse the interplay between interactions (during consultations between clinicians, patients and family members) and clinical and organisational features of the contexts for those interactions. We found that the framing of consultations as being about life-saving or life-enhancing procedures was important in producing three different genres of consultations focused variously on: resolving problems, deliberation of options and evaluation of benefits of surgery. We conclude that medical authority persists, but can be used to create more deliberative opportunities for decision-making through amending the context for consultations in addition to adopting appropriate communication practices during surgical consultations.

A Transcriptomic Approach to Understand Patient Susceptibility to Pneumonia After Abdominal Surgery

OBJECTIVE

To describe immune pathways and gene networks altered following major abdominal surgery and to identify transcriptomic patterns associated with postoperative pneumonia.

BACKGROUND

Nosocomial infections are a major healthcare challenge, developing in over 20% of patients aged 45 or over undergoing major abdominal surgery, with postoperative pneumonia associated with an almost 5-fold increase in 30-day mortality.

METHODS

From a prospective consecutive cohort (n=150) undergoing major abdominal surgery, whole-blood RNA was collected preoperatively and at 3 time-points postoperatively (2-6, 24, and 48 h). Twelve patients diagnosed with postoperative pneumonia and 27 matched patients remaining infection-free were identified for analysis with RNA-sequencing.

RESULTS

Compared to preoperative sampling, 3639 genes were upregulated and 5043 downregulated at 2 to 6 hours. Pathway analysis demonstrated innate-immune activation with neutrophil degranulation and Toll-like-receptor signaling upregulation alongside adaptive-immune suppression. Cell-type deconvolution of preoperative RNA-sequencing revealed elevated S100A8/9-high neutrophils alongside reduced naïve CD4 T-cells in those later developing pneumonia. Preoperatively, a gene-signature characteristic of neutrophil degranulation was associated with postoperative pneumonia acquisition ( P =0.00092). A previously reported Sepsis Response Signature (SRSq) score, reflecting neutrophil dysfunction and a more dysregulated host response, at 48 hours postoperatively, differed between patients subsequently developing pneumonia and those remaining infection-free ( P =0.045). Analysis of the novel neutrophil gene-signature and SRSq scores in independent major abdominal surgery and polytrauma cohorts indicated good predictive performance in identifying patients suffering later infection.

CONCLUSIONS

Major abdominal surgery acutely upregulates innate-immune pathways while simultaneously suppressing adaptive-immune pathways. This is more prominent in patients developing postoperative pneumonia. Preoperative transcriptomic signatures characteristic of neutrophil degranulation and postoperative SRSq scores may be useful predictors of subsequent pneumonia risk.

Method of Anesthesia and Perioperative Risk Factors, Maternal Anesthesia Complications, and Neonatal Mortality Following Cesarean Delivery in Africa: A Substudy of a 7-Day Prospective Observational Cohort Study

BACKGROUND

The African Surgical Outcomes Study (ASOS) found that maternal mortality following cesarean delivery in Africa is 50 times higher than in high-income countries, and associated with obstetric hemorrhage and anesthesia complications. Mothers who died were more likely to receive general anesthesia (GA). The associations between GA versus spinal anesthesia (SA) and preoperative risk factors, maternal anesthesia complications, and neonatal outcomes following cesarean delivery in Africa are unknown.

METHODS

This is a secondary explanatory analysis of 3792 patients undergoing cesarean delivery in ASOS, a prospective observational cohort study, across 22 African countries. The primary aim was to estimate the association between preoperative risk factors and the outcome of the method of anesthesia delivered. Secondary aims were to estimate the association between the method of anesthesia and the outcomes (1) maternal intraoperative hypotension, (2) severe maternal anesthesia complications, and (3) neonatal mortality. Generalized linear mixed models adjusting for obstetric gravidity and gestation, American Society of Anesthesiologists (ASA) category, urgency of surgery, maternal comorbidities, fetal distress, and level of anesthesia provider were used.

RESULTS

Of 3709 patients, SA was performed in 2968 (80%) and GA in 741 (20%). Preoperative factors independently associated with GA for cesarean delivery were gestational age (adjusted odds ratio [aOR], 1.093; 95% confidence interval [CI], 1.052-1.135), ASA categories III (aOR, 11.84; 95% CI, 2.93-46.31) and IV (aOR, 11.48; 95% CI, 2.93-44.93), eclampsia (aOR, 3.92; 95% CI, 2.18-7.06), placental abruption (aOR, 6.23; 95% CI, 3.36-11.54), and ruptured uterus (aOR, 3.61; 95% CI, 1.36-9.63). SA was administered to 48 of 94 (51.1%) patients with eclampsia, 12 of 28 (42.9%) with cardiac disease, 14 of 19 (73.7%) with preoperative sepsis, 48 of 76 (63.2%) with antepartum hemorrhage, 30 of 55 (54.5%) with placenta previa, 33 of 78 (42.3%) with placental abruption, and 12 of 29 (41.4%) with a ruptured uterus. The composite maternal outcome "all anesthesia complications" was more frequent in GA than SA (9/741 [1.2%] vs 3/2968 [0.1%], P < .001). The unadjusted neonatal mortality was higher with GA than SA (65/662 [9.8%] vs 73/2669 [2.7%], P < .001). The adjusted analyses demonstrated no association between method of anesthesia and (1) intraoperative maternal hypotension and (2) neonatal mortality.

CONCLUSIONS

Analysis of patients undergoing anesthesia for cesarean delivery in Africa indicated patients more likely to receive GA. Anesthesia complications and neonatal mortality were more frequent following GA. SA was often administered to high-risk patients, including those with eclampsia or obstetric hemorrhage. Training in the principles of selection of method of anesthesia, and the skills of safe GA and neonatal resuscitation, is recommended.

Prediction, prognosis, and professionalism in perioperative medicine

Guidelines provide a framework to take better care of our patients. They are published by different professional groups and are based on all the research done for us by hardworking colleagues. Compiling a guideline is an enormous amount of work and is generally done with the utmost care. However, recommendations often require a subjective interpretation of published research, where personal and academic interests can influence the outcome. We discuss two recently published guidelines on perioperative cardiovascular assessment that led to different conclusions on some important areas of patient care.

One-year Outcomes after Discharge from Noncardiac Surgery and Association between Predischarge Complications and Death after Discharge: Analysis of the VISION Prospective Cohort Study

BACKGROUND

In previous analyses, myocardial injury after noncardiac surgery, major bleeding, and sepsis were independently associated with most deaths in the 30 days after noncardiac surgery, but most of these deaths occurred during the index hospitalization for surgery. The authors set out to describe outcomes after discharge from hospital up to 1 yr after inpatient noncardiac surgery and associations between predischarge complications and postdischarge death up to 1 yr after surgery.

METHODS

This study was an analysis of patients discharged after inpatient noncardiac surgery in a large international prospective cohort study across 28 centers from 2007 to 2013 of patients aged 45 yr or older followed to 1 yr after surgery. The study estimated (1) the cumulative postdischarge incidence of death and other outcomes up to a year after surgery and (2) the adjusted time-varying associations between postdischarge death and predischarge complications including myocardial injury after noncardiac surgery, major bleeding, sepsis, infection without sepsis, stroke, congestive heart failure, clinically important atrial fibrillation or flutter, amputation, venous thromboembolism, and acute kidney injury managed with dialysis.

RESULTS

Among 38,898 patients discharged after surgery, the cumulative 1-yr incidence was 5.8% (95% CI, 5.5 to 6.0%) for all-cause death and 24.7% (95% CI, 24.2 to 25.1%) for all-cause hospital readmission. Predischarge complications were associated with 33.7% (95% CI, 27.2 to 40.2%) of deaths up to 30 days after discharge and 15.0% (95% CI, 12.0 to 17.9%) up to 1 yr. Most of the association with death was due to myocardial injury after noncardiac surgery (15.6% [95% CI, 9.3 to 21.9%] of deaths within 30 days, 6.4% [95% CI, 4.1 to 8.7%] within 1 yr), major bleeding (15.0% [95% CI, 8.3 to 21.7%] within 30 days, 4.7% [95% CI, 2.2 to 7.2%] within 1 yr), and sepsis (5.4% [95% CI, 2.2 to 8.6%] within 30 days, 2.1% [95% CI, 1.0 to 3.1%] within 1 yr).

CONCLUSIONS

One in 18 patients 45 yr old or older discharged after inpatient noncardiac surgery died within 1 yr, and one quarter were readmitted to the hospital. The risk of death associated with predischarge perioperative complications persists for weeks to months after discharge.

EDITOR’S PERSPECTIVE

Health Resource Utilisation and Disparities: an Ecological Study of Admission Patterns Across Ethnicity in England Between 2017 and 2020

BACKGROUND AND AIM

The COVID-19 pandemic highlighted adverse outcomes in Asian, Black, and ethnic minority groups. More research is required to explore underlying ethnic health inequalities. In this study, we aim to examine pre-COVID ethnic inequalities more generally through healthcare utilisation to contextualise underlying inequalities that were present before the pandemic.

DESIGN

This was an ecological study exploring all admissions to NHS hospitals in England from 2017 to 2020.

METHODS

The primary outcomes were admission rates within ethnic groups. Secondary outcomes included age-specific and age-standardised admission rates. Sub-analysis of admission rates across an index of multiple deprivation (IMD) deciles was also performed to contextualise the impact of socioeconomic differences amongst ethnic categories. Results were presented as a relative ratio (RR) with 95% confidence intervals.

RESULTS

Age-standardised admission rates were higher in Asian (RR 1.40 [1.38-1.41] in 2019) and Black (RR 1.37 [1.37-1.38]) and lower in Mixed groups (RR 0.91 [0.90-0.91]) relative to White. There was significant missingness or misassignment of ethnicity in NHS admissions: with 11.7% of admissions having an unknown/not-stated ethnicity assignment and 'other' ethnicity being significantly over-represented. Admission rates did not mirror the degree of deprivation across all ethnic categories.

CONCLUSIONS

This study shows Black and Asian ethnic groups have higher admission rates compared to White across all age groups and when standardised for age. There is evidence of incomplete and misidentification of ethnicity assignment in NHS admission records, which may introduce bias to work on these datasets. Differences in admission rates across individual ethnic categories cannot solely be explained by socioeconomic status. Further work is needed to identify ethnicity-specific factors of these inequalities to allow targeted interventions at the local level.

A systematic review and meta-analysis of the clinimetric properties of the core outcome measurement instruments for clinical effectiveness trials of nutritional and metabolic interventions in critical illness (CONCISE)

BACKGROUND

CONCISE is an internationally agreed minimum set of outcomes for use in nutritional and metabolic clinical research in critically ill adults. Clinicians and researchers need to be aware of the clinimetric properties of these instruments and understand any limitations to ensure valid and reliable research. This systematic review and meta-analysis were undertaken to evaluate the clinimetric properties of the measurement instruments identified in CONCISE.

METHODS

Four electronic databases were searched from inception to December 2022 (MEDLINE via Ovid, EMBASE via Ovid, CINAHL via Healthcare Databases Advanced Search, CENTRAL via Cochrane). Studies were included if they examined at least one clinimetric property of a CONCISE measurement instrument or recognised variation in adults ≥ 18 years with critical illness or recovering from critical illness in any language. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist for systematic reviews of Patient-Reported Outcome Measures was used. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses were used in line with COSMIN guidance. The COSMIN checklist was used to evaluate the risk of bias and the quality of clinimetric properties. Overall certainty of the evidence was rated using a modified Grading of Recommendations, Assessment, Development and Evaluation approach. Narrative synthesis was performed and where possible, meta-analysis was conducted.

RESULTS

A total of 4316 studies were screened. Forty-seven were included in the review, reporting data for 12308 participants. The Short Form-36 Questionnaire (Physical Component Score and Physical Functioning), sit-to-stand test, 6-m walk test and Barthel Index had the strongest clinimetric properties and certainty of evidence. The Short Physical Performance Battery, Katz Index and handgrip strength had less favourable results. There was limited data for Lawson Instrumental Activities of Daily Living and the Global Leadership Initiative on Malnutrition criteria. The risk of bias ranged from inadequate to very good. The certainty of the evidence ranged from very low to high.

CONCLUSIONS

Variable evidence exists to support the clinimetric properties of the CONCISE measurement instruments. We suggest using this review alongside CONCISE to guide outcome selection for future trials of nutrition and metabolic interventions in critical illness.

TRIAL REGISTRATION

PROSPERO (CRD42023438187). Registered 21/06/2023.

Long-term healthcare use after postoperative complications: an analysis of linked primary and secondary care routine data

Background

Postoperative complications are associated with reduced long-term survival. We characterise healthcare use changes after sentinel postoperative complications.

Methods

We linked primary and secondary care records of patients undergoing elective surgery at four East London hospitals (2012-7) with at least 90 days follow-up. Complication codes (wound infection, urinary tract infection, pneumonia, new stroke, and new myocardial infarction) recorded within 90 days of surgery were identified from primary or secondary care. Outcomes were change in healthcare contact days in the 2 yr before and after surgery, and 2 yr mortality. We report rate ratios (RaR) with 95% confidence intervals and adjusted for baseline healthcare use and confounders using negative binomial regression.

Results

We included 49 913 patients (median age 49 yr [inter-quartile range {IQR}: 34-64]), 27 958 (56.0%) were female. Amongst 3883 (7.8%) patients with complications (median age 58 [IQR: 43-72]), there were 18.4 days per year in contact with healthcare before surgery and 25.3 days after surgery (RaR: 1.38 [1.37-1.39]). Patients without complications (median age 48 [IQR: 33-63]) had 12.3 days per year in contact with healthcare before surgery and 14.0 days after surgery (RaR: 1.14 [1.14-1.15]). The adjusted incidence rate ratio of days in contact with healthcare associated with complications was 1.67 (1.49-1.87). More patients (391; 10.1%) with complications died within 2 yr than those without (1428; 3.1%).

Conclusions

Patients with postoperative complications are older with greater healthcare use before surgery. However, their absolute and relative increases in healthcare use after surgery are greater than patients without complications.

Characterising biological mechanisms underlying ethnicity-associated outcomes in COVID-19 through biomarker trajectories: a multicentre registry analysis

BACKGROUND

Differences in routinely collected biomarkers between ethnic groups could reflect dysregulated host responses to disease and to treatments, and be associated with excess morbidity and mortality in COVID-19.

METHODS

A multicentre registry analysis from patients aged ≥16 yr with SARS-CoV-2 infection and emergency admission to Barts Health NHS Trust hospitals during January 1, 2020 to May 13, 2020 (wave 1) and September 1, 2020 to February 17, 2021 (wave 2) was subjected to unsupervised longitudinal clustering techniques to identify distinct phenotypic patient clusters based on trajectories of routine blood results over the first 15 days of hospital admission. Distribution of trajectory clusters across ethnic categories was determined, and associations between ethnicity, trajectory clusters, and 30-day survival were assessed using multivariable Cox proportional hazards modelling. Secondary outcomes were ICU admission, survival to hospital discharge, and long-term survival to 640 days.

RESULTS

We included 3237 patients with hospital length of stay ≥7 days. In patients who died, there was greater representation of Black and Asian ethnicity in trajectory clusters for C-reactive protein and urea-to-creatinine ratio associated with increased risk of death. Inclusion of trajectory clusters in survival analyses attenuated or abrogated the higher risk of death in Asian and Black patients. Inclusion of C-reactive protein went from hazard ratio (HR) 1.36 [0.95-1.94] to HR 0.97 [0.59-1.59] (wave 1), and from HR 1.42 [1.15-1.75]) to HR 1.04 [0.78-1.39] (wave 2) in Asian patients. Trajectory clusters associated with reduced 30-day survival were similarly associated with worse secondary outcomes.

CONCLUSIONS

Clinical biochemical monitoring of COVID-19 and progression and treatment response in SARS-CoV-2 infection should be interpreted in the context of ethnic background.

Comparison of Cystatin C and Creatinine in the Assessment of Measured Kidney Function during Critical Illness

BACKGROUND

Incomplete recovery of kidney function is an important adverse outcome in survivors of critical illness. However, unlike eGFR creatinine, eGFR cystatin C is not confounded by muscle loss and may improve identification of persistent kidney dysfunction.

METHODS

To assess kidney function during prolonged critical illness, we enrolled 38 mechanically ventilated patients with an expected length of stay of >72 hours near admission to intensive care unit (ICU) in a single academic medical center. We assessed sequential kidney function using creatinine, cystatin C, and iohexol clearance measurements. The primary outcome was difference between eGFR creatinine and eGFR cystatin C at ICU discharge using Bayesian regression modeling. We simultaneously measured muscle mass by ultrasound of the rectus femoris to assess the confounding effect on serum creatinine generation.

RESULTS

Longer length of ICU stay was associated with greater difference between eGFR creatinine and eGFR cystatin C at a predicted rate of 2 ml/min per 1.73 m 2 per day (95% confidence interval [CI], 1 to 2). By ICU discharge, the posterior mean difference between creatinine and cystatin C eGFR was 33 ml/min per 1.73 m 2 (95% credible interval [CrI], 24 to 42). In 27 patients with iohexol clearance measured close to ICU discharge, eGFR creatinine was on average two-fold greater than the iohexol gold standard, and posterior mean difference was 59 ml/min per 1.73 m 2 (95% CrI, 49 to 69). The posterior mean for eGFR cystatin C suggested a 22 ml/min per 1.73 m 2 (95% CrI, 13 to 31) overestimation of measured GFR. Each day in ICU resulted in a predicted 2% (95% CI, 1% to 3%) decrease in muscle area. Change in creatinine-to-cystatin C ratio showed good longitudinal, repeated measures correlation with muscle loss, R =0.61 (95% CI, 0.50 to 0.72).

CONCLUSIONS

eGFR creatinine systematically overestimated kidney function after prolonged critical illness. Cystatin C better estimated true kidney function because it seemed unaffected by the muscle loss from prolonged critical illness.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Skeletal Muscle Wasting and Renal Dysfunction After Critical Illness Trauma - Outcomes Study (KRATOS), NCT03736005 .

Long-term disease interactions amongst surgical patients: a population cohort study

BACKGROUND

The average age of the surgical population continues to increase, as does prevalence of long-term diseases. However, outcomes amongst multi-morbid surgical patients are not well described.

METHODS

We included adults undergoing non-obstetric surgical procedures in the English National Health Service between January 2010 and December 2015. Patients could be included multiple times in sequential 90-day procedure spells. Multi-morbidity was defined as presence of two or more long-term diseases identified using a modified Charlson comorbidity index. The primary outcome was 90-day postoperative death. Secondary outcomes included emergency hospital readmission within 90 days. We calculated age- and sex-adjusted odds ratios (OR) with 95% confidence intervals (CI) using logistic regression. We compared the outcomes associated with different disease combinations.

RESULTS

We identified 20 193 659 procedure spells among 13 062 715 individuals aged 57 (standard deviation 19) yr. Multi-morbidity was present among 2 577 049 (12.8%) spells with 195 965 deaths (7.6%), compared with 17 616 610 (88.2%) spells without multi-morbidity with 163 529 deaths (0.9%). Multi-morbidity was present in 1 902 859/16 946 808 (11.2%) elective spells, with 57 663 deaths (2.7%, OR 4.9 [95% CI: 4.9-4.9]), and 674 190/3 246 851 (20.7%) non-elective spells, with 138 302 deaths (20.5%, OR 3.0 [95% CI: 3.0-3.1]). Emergency readmission followed 547 399 (22.0%) spells with multi-morbidity compared with 1 255 526 (7.2%) without. Multi-morbid patients accounted for 57 663/114 783 (50.2%) deaths after elective spells, and 138 302/244 711 (56.5%) after non-elective spells. The rate of death varied five-fold from lowest to highest risk disease pairs.

CONCLUSION

One in eight patients undergoing surgery have multi-morbidity, accounting for more than half of all postoperative deaths. Disease interactions amongst multi-morbid patients is an important determinant of patient outcome.

Fluid Optimisation in Emergency Laparotomy (FLO-ELA) Trial: study protocol for a multi-centre randomised trial of cardiac output-guided fluid therapy compared to usual care in patients undergoing major emergency gastrointestinal surgery

INTRODUCTION

Postoperative morbidity and mortality in patients undergoing major emergency gastrointestinal surgery are a major burden on healthcare systems. Optimal management of perioperative intravenous fluids may reduce mortality rates and improve outcomes from surgery. Previous small trials of cardiac-output guided haemodynamic therapy algorithms in patients undergoing gastrointestinal surgery have suggested this intervention results in reduced complications and a modest reduction in mortality. However, this existing evidence is based mainly on elective (planned) surgery, with little evaluation in the emergency setting. There are fundamental clinical and pathophysiological differences between the planned and emergency surgical setting which may influence the effects of this intervention. A large definitive trial in emergency surgery is needed to confirm or refute the potential benefits observed in elective surgery and to inform widespread clinical practice.

METHODS

The FLO-ELA trial is a multi-centre, parallel-group, open, randomised controlled trial. 3138 patients aged 50 and over undergoing major emergency gastrointestinal surgery will be randomly allocated in a 1:1 ratio using minimisation to minimally invasive cardiac output monitoring to guide protocolised administration of intra-venous fluid, or usual care without cardiac output monitoring. The trial intervention will be carried out during surgery and for up to 6 h postoperatively. The trial is funded through an efficient design call by the National Institute for Health and Care Research Health Technology Assessment (NIHR HTA) programme and uses existing routinely collected datasets for the majority of data collection. The primary outcome is the number of days alive and out of hospital within 90 days of randomisation. Participants and those delivering the intervention will not be blinded to treatment allocation. Participant recruitment started in September 2017 with a 1-year internal pilot phase and is ongoing at the time of publication.

DISCUSSION

This will be the largest contemporary randomised trial examining the effectiveness of perioperative cardiac output-guided haemodynamic therapy in patients undergoing major emergency gastrointestinal surgery. The multi-centre design and broad inclusion criteria support the external validity of the trial. Although the clinical teams delivering the trial interventions will not be blinded, significant trial outcome measures are objective and not subject to detection bias.

TRIAL REGISTRATION

ISRCTN 14729158. Registered on 02 May 2017.

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.

Postoperative outcomes associated with surgical care for women in Africa: an international risk-adjusted analysis of prospective observational cohorts

Background

Improving women's health is a critical component of the sustainable development goals. Although obstetric outcomes in Africa have received significant focus, non-obstetric surgical outcomes for women in Africa remain under-examined.

Methods

We did a secondary analysis of the African Surgical Outcomes Study (ASOS) and International Surgical Outcomes Study (ISOS), two 7-day prospective observational cohort studies of outcomes after adult inpatient surgery. This sub-study focuses specifically on the analysis of the female, elective, non-obstetric, non-gynaecological surgical data collected during these two large multicentre studies. The African data from both cohorts are compared with international (non-African) outcomes in a risk-adjusted logistic regression analysis using a generalised linear mixed-effects model. The primary outcome was severe postoperative complications including in-hospital mortality in Africa compared with non-African outcomes.

Results

A total of 1698 African participants and 18 449 international participants met the inclusion criteria. The African cohort were younger than the international cohort with a lower preoperative risk profile. Severe complications occurred in 48 (2.9%) of 1671, and 431 (2.3%) of 18 449 patients in the African and international cohorts, respectively, with in-hospital mortality after severe complications of 23/48 (47.9%) in Africa and 78/431 (18.1%) internationally. Women in Africa had an adjusted odds ratio of 2.06 (95% confidence interval, 1.17-3.62; P=0.012) of developing a severe postoperative complication after elective non-obstetric, non-gynaecological surgery, compared with the international cohort.

Conclusions

Women in Africa have double the risk adjusted odds of severe postoperative complications (including in-hospital mortality) after elective non-obstetric, non-gynaecological surgery compared with the international incidence.

Measurement properties of the WHO Disability Assessment Schedule 2.0 for evaluating functional status after inpatient surgery

BACKGROUND

Expert recommendations propose the WHO Disability Assessment Schedule (WHODAS) 2.0 as a core outcome measure in surgical studies, yet data on its long-term measurement properties remain limited. These were evaluated in a secondary analysis of the Measurement of Exercise Tolerance before Surgery (METS) prospective cohort.

METHODS

Participants were adults (40 years of age or older) who underwent inpatient non-cardiac surgery. The 12-item WHODAS and EQ-5DTM-3L questionnaires were administered preoperatively (in person) and 1 year postoperatively (by telephone). Responsiveness was characterized using standardized response means (SRMs) and correlation coefficients between change scores. Construct validity was evaluated using correlation coefficients between 1-year scores and comparisons of WHODAS scores across clinically relevant subgroups.

RESULTS

The analysis included 546 patients. There was moderate correlation between changes in WHODAS and various EQ-5DTM subscales. The strongest correlation was between changes in WHODAS and changes in the functional domains of the EQ-5D-3L-for example, mobility (Spearman's rho 0.40, 95 per cent confidence interval [c.i.] 0.32 to 0.48) and usual activities (rho 0.45, 95 per cent c.i. 0.30 to 0.52). When compared across quartiles of EQ-5D index change, median WHODAS scores followed expected patterns of change. In subgroups with expected functional status changes, the WHODAS SRMs ranged from 'small' to 'large' in the expected directions of change. At 1 year, the WHODAS demonstrated convergence with the EQ-5D-3L functional domains, and good discrimination between patients with expected differences in functional status.

CONCLUSION

The WHODAS questionnaire has construct validity and responsiveness as a measure of functional status at 1 year after major surgery.

Latin American surgical outcomes study: study protocol for a multicentre international observational cohort study of patient outcomes after surgery in Latin American countries

Background

Reported data suggest that 4.2 million deaths will occur within 30 days of surgery worldwide each year, half of which are in low- and middle-income countries. Postoperative complications are a leading cause of long-term morbidity and mortality. Patients who survive and leave the hospital after surgical complications regularly experience reductions in long-term survival and functional independence, resulting in increased costs. With a high volume of surgery performed, there is a growing perception of the substantial impact of even minor enhancements in perioperative care. The Latin American Surgical Outcomes Study (LASOS) is an international, multicentre, prospective cohort study of adults submitted to in-patient surgery in Latin America aiming to provide detailed data describing postoperative complications and surgical mortality.

Methods

LASOS is a 7 day cohort study of adults undergoing surgery in Latin America. Details of preoperative risk factors, intraoperative care, and postoperative outcomes will be collected. The primary outcome will be in-hospital postoperative complications of any cause. Secondary outcomes include in-hospital all-cause mortality, duration of hospital stay after surgery, and admission to a critical care unit within 30 days after surgery during the index hospitalisation.

Results

The LASOS results will be published in peer-reviewed journals, reported and presented at international meetings, and widely disseminated to patients and public in participating countries via mainstream and social media.

Conclusions

The LASOS may augment our understanding of postoperative complications and surgial mortality in Latin America.

Clinical trial registration

NCT05169164.

Contemporary use of antimicrobial prophylaxis for surgical patients: An observational cohort study

BACKGROUND

Antimicrobial prophylaxis is commonly used to prevent surgical site infection (SSI), despite concerns of overuse leading to antimicrobial resistance. However, it is unclear how often antimicrobials are used and whether guidelines are followed.

OBJECTIVES

To describe contemporary clinical practice for antimicrobial prophylaxis including guideline compliance, the rate of postoperative infection and associated side effects.

DESIGN

A prospective, multicentre, observational cohort study.

SETTING

Twelve United Kingdom National Health Service hospitals.

PARTICIPANTS

One thousand one hundred and sixteen patients, aged at least 18 years undergoing specific colo-rectal, obstetric, gynaecological, urological or orthopaedic surgical procedures.

EXPOSURE

Compliance with guidelines for antimicrobial prophylaxis.

OUTCOMES

The primary outcome was SSI within 30 days after surgery. Secondary outcomes were number of doses of antimicrobials for prophylaxis and to treat infection, incidence of antimicrobial-related side effects and mortality within 30 days after surgery. Data are presented as number with percentage (%) or median with interquartile range [IQR].Results of logistic regression analyses are presented as odds ratio/rate ratio (OR/RR) with 95% confidence intervals (95% CIs).

RESULTS

1102 out of 1106 (99.6%) patients received antimicrobial prophylaxis, which was compliant with local guidelines in 929 out of 1102 (84.3%) cases. 2169 out of 51 28 (42.3%) doses of antimicrobials were administered as prophylaxis (median 1 [1 to 2] dose) and 2959 out of 5128 (57.7%) were administered to treat an infection (median 21 [11 to 28] doses). 56 patients (5.2%) developed SSI. Antimicrobial prophylaxis administered according to local guidelines was not associated with a lower incidence of SSI compared with administration outside guidelines [OR 0.90 (0.35 to 2.29); P  = 0.823]. 23 out of 1072 (2.2%) patients experienced a side effect of antimicrobial therapy. 7 out of 1082 (0.6%) patients died. The median hospital stay was 3 [1 to 5] days.

CONCLUSION

Antimicrobial prophylaxis was administered for almost all the surgical procedures under investigation. However, this was not always compliant with guidelines. Further research is required to determine whether the amount of prophylactic antimicrobials could be safely and effectively reduced without increasing the incidence of SSI.

The need for data describing the surgical population in Latin America

Latin American countries have a huge diversity in sociocultural factors, ethnicity, geography, and political systems. Provision of healthcare varies widely in Latin America, and it is unclear how these disparities relate to outcomes for individual patients undergoing surgery. The Latin American Surgical Outcome Study (LASOS), with its pragmatic design, will provide a snapshot of surgical activity throughout Latin America and identify the next steps needed to improve postoperative outcomes.

Enhanced peri-operative care to improve outcomes for high-risk surgical patients in Brazil: a single-centre before-and-after cohort study

Mortality and morbidity for high-risk surgical patients are often high, especially in low-resource settings. Enhanced peri-operative care has the potential to reduce preventable deaths but must be designed to meet local needs. This before-and-after cohort study aimed to assess the effectiveness of a postoperative 48-hour enhanced care pathway for high-risk surgical patients ('high-risk surgical bundle') who did not meet the criteria for elective admission to intensive care. The pathway comprised of six elements: risk identification and communication; adoption of a high-risk post-anaesthesia care unit discharge checklist; prompt nursing admission to ward; intensification of vital signs monitoring; troponin measurement; and prompt access to medical support if required. The primary outcome was in-hospital mortality. Data describing 1189 patients from two groups, before and after implementation of the pathway, were compared. The usual care group comprised a retrospective cohort of high-risk surgical patients between September 2015 and December 2016. The intervention group prospectively included high-risk surgical patients from February 2019 to March 2020. Unadjusted mortality rate was 10.5% (78/746) for the usual care and 6.3% (28/443) for the intervention group. After adjustment, the intervention effect remained significant (RR 0.46 (95%CI 0.30-0.72). The high-risk surgical bundle group received more rapid response team calls (24% vs. 12.6%; RR 0.63 [95%CI 0.49-0.80]) and surgical re-interventions (18.9 vs. 7.5%; RR 0.41 [95%CI 0.30-0.59]). These data suggest that a clinical pathway based on enhanced surveillance for high-risk surgical patients in a resource-constrained setting could reduce in-hospital mortality.

Mandatory vaccination of National Health Service staff against COVID-19: more harm than good?

Despite the clear benefits of vaccination against COVID-19, there was significant unease relating to the government policy of mandatory vaccination of health and care staff in England and the potential inequities this may lead to. Healthcare staff, and in particular doctors, speaking out on this issue may have inadvertently provided a narrative, which undermined the objective of achieving widespread vaccination of populations against this serious disease. The recent reversal of this policy may not mark the end of this debate amongst health and social care staff.

Postoperative Outcomes Associated With Procedural Sedation Conducted by Physician and Nonphysician Anesthesia Providers: Findings From the Prospective, Observational African Surgical Outcomes Study

BACKGROUND

There is an unmet need for essential surgical services in Africa. Limited anesthesia services are a contributing factor. Nonphysician anesthesia providers are utilized to assist with providing anesthesia and procedural sedation to make essential surgeries available. There is a paucity of data on outcomes following procedural sedation for surgery in Africa. We investigated the postoperative outcomes following procedural sedation by nonphysicians and physicians in Africa. We hypothesized that the level of training of the sedation provider may be associated with the incidence of severe postoperative complications and death.

METHODS

A secondary analysis of a prospective cohort of inhospital adult surgical patients representing 25 African countries was performed. The primary outcome was a collapsed composite of inhospital severe postoperative complications and death. We assessed the association between receiving procedural sedation conducted by a nonphysician (versus physician) and the composite outcome using logistic regression. We used the inverse probability of treatment weighting propensity score method to adjust for potential confounding variables including patient age, hemoglobin level, American Society of Anesthesiologists (ASA) physiological status, diabetes mellitus, urgency of surgery, severity of surgery, indication for surgery, surgical discipline, seniority of the surgical team, hospital level of specialization, and hospital funding system using public or private funding. All patients who only received procedural sedation for surgery were included.

RESULTS

Three hundred thirty-six patients met the inclusion criteria, of which 98 (29.2%) received sedation from a nonphysician provider. The incidence of severe postoperative complications and death was 10 of 98 (10.2%) in the nonphysician group and 5 of 238 (2.1%) in the physician group. The estimated association between procedural sedation conducted by a nonphysician provider and inhospital outcomes was an 8-fold increase in the odds of severe complications and/or death, with an odds ratio (95% confidence interval [CI]) of 8.3 (2.7-25.6).

CONCLUSIONS

The modest number of observations in this secondary data analysis suggests that shifting the task of procedural sedation from physicians to nonphysicians to increase access to care may be associated with severe postoperative complications and death in Africa. Research focusing on identifying factors contributing to adverse outcomes associated with procedural sedation is necessary to make this practice safer.

Death after surgery among patients with chronic disease: prospective study of routinely collected data in the English NHS

BACKGROUND

Five million surgeries take place in the NHS each year. Little is known about the prevalence of chronic diseases among these patients, and the association with postoperative outcomes.

METHODS

Analysis of routine data from all NHS hospitals in England including patients aged ≥18 yr undergoing non-obstetric surgery between January 1, 2010 and December 31, 2015. The primary outcome was death within 90 days after surgery. For each chronic disease, we adjusted for age, sex, presence of other diseases, emergency surgery, and year using logistic regression models. We defined high-risk diseases as those with an adjusted odds ratio (OR) for death ≥2 and report associated 2-yr survival.

RESULTS

We included 8 624 611 patients (median age, 53 [36-68] yr), of whom 6 913 451 (80.2%) underwent elective surgery and 1 711 160 (19.8%) emergency surgery. Overall, 2 311 600 (26.8%) patients had a chronic disease, of whom 109 686 (4.7%) died within 90 days compared with 24 136 (0.4%) of 6 313 011 without chronic disease. Respiratory disease (1 002 281 [11.6%]), diabetes mellitus (662 706 [7.7%]), and cancer (310 363; 3.6%) were the most common. Four chronic diseases accounted for 7.7% of patients but 59.0% of deaths: cancer (37 693 deaths [12.1%]; OR=8.3 [8.2-8.5]), liver disease (8638 deaths [10.3%]; OR=4.5 [4.4-4.7]), cardiac failure (26 604 deaths [12.6%]; OR=2.4 [2.4-2.5]), and dementia (19 912 deaths [17.9%]; OR=2.0 [1.9-2.0]). Two-year survival was 67.7% among patients with high-risk chronic disease, compared with 97.1% without.

CONCLUSION

One in four surgical patients has a chronic disease with an associated 10-fold increase in risk of postoperative death. Two-thirds of all deaths after surgery occur among patients with high-risk diseases (cancer, cardiac failure, liver disease, dementia).

Routine postoperative noninvasive respiratory support and pneumonia after elective surgery: a systematic review and meta-analysis of randomised trials

BACKGROUND

Postoperative pulmonary complications, including pneumonia, are a substantial cause of morbidity. We hypothesised that routine noninvasive respiratory support was associated with a lower incidence of pneumonia after surgery.

METHODS

Systematic review and meta-analysis of RCTs comparing the routine use of continuous positive airway pressure (CPAP), noninvasive ventilation (NIV), or high-flow nasal oxygen (HFNO) against standard postoperative care in the adult population. We searched MEDLINE (PubMed), EMBASE, and CENTRAL from the start of indexing to July 27, 2021. Articles were reviewed and data extracted in duplicate, with discrepancies resolved by a senior investigator. The primary outcome was pneumonia, and the secondary outcome was postoperative pulmonary complications. We calculated risk difference (RD) with 95% confidence intervals using DerSimonian and Laird random effects models. We assessed risk of bias using the Cochrane risk of bias tool.

RESULTS

From 18 513 records, we included 38 trials consisting of 9782 patients. Pneumonia occurred in 214/4403 (4.9%) patients receiving noninvasive respiratory support compared with 216/3937 (5.5%) receiving standard care (RD -0.01 [95% confidence interval: -0.02 to 0.00]; I²=8%; P=0.23). Postoperative pulmonary complications occurred in 393/1379 (28%) patients receiving noninvasive respiratory support compared with 280/902 (31%) receiving standard care (RD -0.11 [-0.23 to 0.01]; I²=79%; P=0.07). Subgroup analyses did not identify a benefit of CPAP, NIV, or HFNO in preventing pneumonia. Tests for publication bias suggest six unreported trials.

CONCLUSION

The results of this evidence synthesis do not support the routine use of postoperative CPAP, NIV, or HFNO to prevent pneumonia after surgery in adults.

CLINICAL TRIAL REGISTRATION

PROSPERO: CRD42019156741.

Acute kidney injury in COVID-19: multicentre prospective analysis of registry data

Background

Acute kidney injury (AKI) is a common and important complication of coronavirus disease 2019 (COVID-19). Further characterization is required to reduce both short- and long-term adverse outcomes.

Methods

We examined registry data including adults with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection admitted to five London Hospitals from 1 January to 14 May 2020. Prior end-stage kidney disease was excluded. Early AKI was defined by Kidney Disease: Improving Global Outcomes creatinine criteria within 7 days of admission. Independent associations of AKI and survival were examined in multivariable analysis. Results are given as odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals.

Results

Among 1855 admissions, 455 patients (24.5%) developed early AKI: 200 (44.0%) Stage 1, 90 (19.8%) Stage 2 and 165 (36.3%) Stage 3 (74 receiving renal replacement therapy). The strongest risk factor for AKI was high C-reactive protein [OR 3.35 (2.53-4.47), P < 0.001]. Death within 30 days occurred in 242 (53.2%) with AKI compared with 255 (18.2%) without. In multivariable analysis, increasing severity of AKI was incrementally associated with higher mortality: Stage 3 [HR 3.93 (3.04-5.08), P < 0.001]. In 333 patients with AKI surviving to Day 7, 134 (40.2%) recovered, 47 (14.1%) recovered then relapsed and 152 (45.6%) had persistent AKI at Day 7; an additional 105 (8.2%) patients developed AKI after Day 7. Persistent AKI was strongly associated with adjusted mortality at 90 days [OR 7.57 (4.50-12.89), P < 0.001].

Conclusions

AKI affected one in four hospital in-patients with COVID-19 and significantly increased mortality. Timing and recovery of COVID-19 AKI is a key determinant of outcome.

Ethnicity and acute hospital admissions: Multi-center analysis of routine hospital data

Background: The effects of ethnic and social inequalities on patient outcomes in acute healthcare remain poorly understood. Methods: Prospectively-defined analysis of registry data from four acute NHS hospitals in east London including all patients ≥ 18 years with a first emergency admission between 1st January 2013 and 31st December 2018. We calculated adjusted one-year mortality risk using logistic regression. Results are presented as n (%), median (IQR), and odds ratios (OR) with 95% confidence intervals. Findings: We included 203,182 patients. 43,101 (21%) patients described themselves as Asian, 21,388 (10.5%) Black, 2,982 (1.4%) Mixed, 13,946 (6.8%) Other ethnicity, and 100,065 (49%) White. We excluded 21,700 (10.7%) patients with undisclosed ethnicity. 16,054 (7.9%) patients died within one year. Non-white patients were younger (Asian: 43 [31-62] years; Black: 48 [33-63] years; Mixed 36 [26-52] years) than White patients (55 [35-75] years), with a higher incidence of comorbid disease. In each age-group, non-white patients were more likely to be admitted to hospital. This effect was greatest in the ≥ 80 years age-group (32% non-white admitted to hospital versus 23% non-white in community population). Deprivation was associated with increased mortality in all ethnic groups (OR 1.41 [1.33-1.50]; p < 0.001). However, when adjusted for age, Asian (0.69 [0.66-0.73], p < 0.0001) and Black patients (0.79 [0.74-0.85]; p < 0.0001) experienced a lower mortality risk than White patients. Interpretation: Ethnic and social disparities are associated with important differences in acute health outcomes. However, these differences are masked by statistical adjustment because patients from ethnic minorities present at a younger age. Funding: None.

Mortality after surgery with SARS-CoV-2 infection in England: a population-wide epidemiological study

BACKGROUND

The COVID-19 pandemic has heavily impacted elective and emergency surgery around the world. We aimed to confirm the incidence of perioperative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and associated mortality after surgery.

METHODS

Analysis of routine electronic health record data from NHS hospitals in England. We extracted data from Hospital Episode Statistics in England describing adult patients undergoing surgery between January 1, 2020 and February 28, 2021. The exposure was SARS-CoV-2 infection defined by International Classification of Diseases (ICD)-10 codes. The primary outcome measure was 90 day in-hospital mortality. Data were analysed using multivariable logistic regression adjusted for age, sex, Charlson Comorbidity Index, Index of Multiple Deprivation, presence of cancer, surgical procedure type and admission acuity. Results are presented as n (%) and odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

We identified 2 666 978 patients undergoing surgery of whom 28 777 (1.1%) had SARS-CoV-2 infection. In total, 26 364 (1.0%) patients died in hospital. SARS-CoV-2 infection was associated with a much greater risk of death (SARS-CoV-2: 6153/28 777 [21.4%] vs no SARS-CoV-2: 20 211/2 638 201 [0.8%]; OR=5.7 [95% CI, 5.5-5.9]; P<0.001). Amongst patients undergoing elective surgery, 2412/1 857 586 (0.1%) had SARS-CoV-2, of whom 172/2412 (7.1%) died, compared with 1414/1 857 586 (0.1%) patients without SARS-CoV-2 (OR=25.8 [95% CI, 21.7-30.9]; P<0.001). Amongst patients undergoing emergency surgery, 22 918/582 292 (3.9%) patients had SARS-CoV-2, of whom 5752/22 918 (25.1%) died, compared with 18 060/559 374 (3.4%) patients without SARS-CoV-2 (OR=5.5 [95% CI, 5.3-5.7]; P<0.001).

CONCLUSIONS

The low incidence of SARS-CoV-2 infection in NHS surgical pathways suggests current infection prevention and control policies are highly effective. However, the high mortality amongst patients with SARS-CoV-2 suggests these precautions cannot be safely relaxed.

Functional decline after major elective non-cardiac surgery: a multicentre prospective cohort study

Self-reported postoperative functional recovery is an important patient-centred outcome that is rarely measured or considered in research and decision-making. We conducted a secondary analysis of the measurement of exercise tolerance before surgery (METS) study for associations of peri-operative variables with functional decline after major non-cardiac surgery. Patients who were at least 40 years old, had or were at risk of, coronary artery disease and who were scheduled for non-cardiac surgery were recruited. Primary outcome was a reduction in mobility, self-care or ability to conduct usual activities (EuroQol 5 dimension) from before surgery to 30 days and 1 year after surgery. A decline in at least one function was reported by 523/1309 (40%) participants at 30 days and 320/1309 (24%) participants at 1 year. Participants who reported higher pre-operative Duke Activity Status indices more often reported functional decline 30 days after surgery and less often reported functional decline 1 year after surgery. The odds ratios (95%CI) of functional decline 30 days and 1 year after surgery with moderate or severe postoperative complications were 1.46 (1.02-2.09), p = 0.037 and 1.44 (0.98-2.13), p = 0.066. Discrimination of participants who reported functional decline 30 days and 1 year after surgery were poor (c-statistic 0.61 and 0.63, respectively). In summary, one quarter of participants reported functional decline up to one postoperative year.

Surgical activity in England and Wales during the COVID-19 pandemic: a nationwide observational cohort study

BACKGROUND

A significant proportion of healthcare resource has been diverted to the care of those with COVID-19. This study reports the volume of surgical activity and the number of cancelled surgical procedures during the COVID-19 pandemic.

METHODS

We used hospital episode statistics for all adult patients undergoing surgery between January 1, 2020 and December 31, 2020 in England and Wales. We identified surgical procedures using a previously published list of procedure codes. Procedures were stratified by urgency of surgery as defined by NHS England. We calculated the deficit of surgical activity by comparing the expected number of procedures from 2016 to 2019 with the actual number of procedures in 2020. Using a linear regression model, we calculated the expected cumulative number of cancelled procedures by December 31, 2021.

RESULTS

The total number of surgical procedures carried out in England and Wales in 2020 was 3 102 674 compared with the predicted number of 4 671 338 (95% confidence interval [CI]: 4 218 740-5 123 932). This represents a 33.6% reduction in the national volume of surgical activity. There were 763 730 emergency surgical procedures (13.4% reduction) compared with 2 338 944 elective surgical procedures (38.6% reduction). The cumulative number of cancelled or postponed procedures was 1 568 664 (95% CI: 1 116 066-2 021 258). We estimate that this will increase to 2 358 420 (95% CI: 1 667 587-3 100 808) up to December 31, 2021.

CONCLUSIONS

The volume of surgical activity in England and Wales was reduced by 33.6% in 2020, resulting in more than 1.5 million cancelled operations. This deficit will continue to grow in 2021.

The effects of preoperative moderate to severe anaemia on length of hospital stay: A propensity score-matched analysis in non-cardiac surgery patients

BACKGROUND

Anaemia is frequently recorded during preoperative screening and has been suggested to affect outcomes after surgery negatively.

OBJECTIVES

The objectives were to assess the frequency of moderate to severe anaemia and its association with length of hospital stay.

DESIGN

Post hoc analysis of the international observational prospective 'Local ASsessment of VEntilatory management during General Anaesthesia for Surgery' (LAS VEGAS) study.

PATIENTS AND SETTING

The current analysis included adult patients requiring general anaesthesia for non-cardiac surgery. Preoperative anaemia was defined as a haemoglobin concentration of 11 g dl-1 or lower, thus including moderate and severe anaemia according to World Health Organisation criteria.

MAIN OUTCOME MEASURES

The primary outcome was length of hospital stay. Secondary outcomes included hospital mortality, intra-operative adverse events and postoperative pulmonary complications (PPCs).

RESULTS

Haemoglobin concentrations were available for 8264 of 9864 patients. Preoperative moderate to severe anaemia was present in 7.7% of patients. Multivariable analysis showed that preoperative moderate to severe anaemia was associated with an increased length of hospital stay with a mean difference of 1.3 ((95% CI 0.8 to 1.8) days; P < .001). In the propensity-matched analysis, this association remained present, median 4.0 [IQR 1.0 to 5.0] vs. 2.0 [IQR 0.0 to 5.0] days, P = .001. Multivariable analysis showed an increased in-hospital mortality (OR 2.9 (95% CI 1.1 to 7.5); P  = .029), and higher incidences of intra-operative hypotension (36.3 vs. 25.3%; P < .001) and PPCs (17.1 vs. 10.5%; P = .001) in moderately to severely anaemic patients. However, this was not confirmed in the propensity score-matched analysis.

CONCLUSIONS

In this international cohort of non-cardiac surgical patients, preoperative moderate to severe anaemia was associated with a longer duration of hospital stay but not increased intra-operative complications, PPCs or in-hospital mortality.

TRIAL REGISTRATION

The LAS VEGAS study was registered at Clinicaltrials.gov, NCT01601223.

Mode of blood pressure monitoring and morbidity after noncardiac surgery: A prospective multicentre observational cohort study

BACKGROUND

Control of blood pressure remains a key goal of peri-operative care, because hypotension is associated with adverse outcomes after surgery.

OBJECTIVES

We explored whether increased vigilance afforded by intra-arterial blood pressure monitoring may be associated with less morbidity after surgery.

DESIGN

A prospective observational cohort study.

SETTING

Four UK secondary care hospitals.

PATIENTS

A total of 4342 patients ≥45 years who underwent noncardiac surgery.

METHODS

We compared outcome of patients who received peri-operative intra-arterial blood pressure monitoring with those whose blood pressure was measured noninvasively.

OUTCOMES

The primary outcome was peri-operative myocardial injury (high-sensitivity troponin-T ≥ 15 ng l-1 within 72 h after surgery), compared between patients who received intra-arterial versus noninvasive blood pressure monitoring. Secondary outcomes were morbidity within 72 h of surgery (postoperative morbidity survey), and vasopressor and fluid therapy. Multivariable logistic regression analysis explored associations between morbidity and age, sex, location of postoperative care, mode of blood pressure/haemodynamic monitoring and Revised Cardiac Risk Index.

RESULTS

Intra-arterial monitoring was used in 1137/4342 (26.2%) patients. Myocardial injury occurred in 440/1137 (38.7%) patients with intra-arterial monitoring compared with 824/3205 (25.7%) with noninvasive monitoring [OR 1.82 (95% CI 1.58 to 2.11), P < 0.001]. Intra-arterial monitoring remained associated with myocardial injury when adjusted for potentially confounding variables [adjusted OR 1.56 (1.29 to 1.89), P < 0.001). The results were similar for planned ICU versus ward postoperative care.

CONCLUSIONS

Intra-arterial monitoring is associated with greater risk of morbidity after noncardiac surgery, after controlling for surgical and patient factors. These data provide useful insights into the design of a definitive monitoring trial.

Postoperative infection and mortality following elective surgery in the International Surgical Outcomes Study (ISOS)

BACKGROUND

Postoperative infection is one of the most frequent and important complications after surgery. The epidemiology of infection following elective surgery remains poorly described.

METHODS

This was a prospective analysis of the International Surgical Outcomes Study (ISOS) describing infection by 30 days after elective surgery. Associations between postoperative infection (primary outcome) and baseline demographic, surgical, and anaesthetic risk factors were assessed. Analyses were carried out using logistic and linear regression models. Secondary outcomes were 30-day mortality and duration of hospital stay. Treatments received by patients after different types of infection were evaluated.

RESULTS

Some 44 814 patients were included in the analysis, with a total of 4032 infections occurring in 2927 patients (6.5 per cent). Overall, 206 patients died, of whom 99 of 2927 (3.4 per cent) had infection. Some 737 of 4032 infections (18.3 per cent) were severe; the most frequent types were superficial surgical-site infection (1320, 32.7 per cent), pneumonia (708, 17.6 per cent), and urinary tract infection (681, 16.9 per cent). Excluding missing data, antimicrobials were used in 2126 of 2749 infections (77.3 per cent), and 522 of 2164 patients (24.1 per cent) required admission to critical care. Factors associated with an increased incidence of infection in adjusted analyses were: age, male sex, ASA grade, co-morbid disease, preoperative anaemia, anaesthetic technique, surgical category, surgical severity, and cancer surgery. Infection significantly increased the risk of death (odds ratio 4.68, 95 per cent c.i. 3.39 to 6.47; P < 0.001), and duration of hospital stay by on average 6.45 (6.23 to 6.66) days (P < 0.001).

CONCLUSION

Infection is a common complication after elective surgery. Recognition of modifiable risk factors will help inform appropriate prevention strategies.

The Association of Intraoperative driving pressure with postoperative pulmonary complications in open versus closed abdominal surgery patients - a posthoc propensity score-weighted cohort analysis of the LAS VEGAS study

BACKGROUND

It is uncertain whether the association of the intraoperative driving pressure (ΔP) with postoperative pulmonary complications (PPCs) depends on the surgical approach during abdominal surgery. Our primary objective was to determine and compare the association of time-weighted average ΔP (ΔP_TW) with PPCs. We also tested the association of ΔP_TW with intraoperative adverse events.

METHODS

Posthoc retrospective propensity score-weighted cohort analysis of patients undergoing open or closed abdominal surgery in the 'Local ASsessment of Ventilatory management during General Anaesthesia for Surgery' (LAS VEGAS) study, that included patients in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs. The secondary endpoint was a composite of intraoperative adverse events.

RESULTS

The analysis included 1128 and 906 patients undergoing open or closed abdominal surgery, respectively. The PPC rate was 5%. ΔP was lower in open abdominal surgery patients, but ΔP_TW was not different between groups. The association of ΔP_TW with PPCs was significant in both groups and had a higher risk ratio in closed compared to open abdominal surgery patients (1.11 [95%CI 1.10 to 1.20], P <  0.001 versus 1.05 [95%CI 1.05 to 1.05], P <  0.001; risk difference 0.05 [95%CI 0.04 to 0.06], P <  0.001). The association of ΔP_TW with intraoperative adverse events was also significant in both groups but had higher odds ratio in closed compared to open abdominal surgery patients (1.13 [95%CI 1.12- to 1.14], P <  0.001 versus 1.07 [95%CI 1.05 to 1.10], P <  0.001; risk difference 0.05 [95%CI 0.030.07], P <  0.001).

CONCLUSIONS

ΔP is associated with PPC and intraoperative adverse events in abdominal surgery, both in open and closed abdominal surgery.

TRIAL REGISTRATION

LAS VEGAS was registered at clinicaltrials.gov (trial identifier NCT01601223 ).

Resource requirements for reintroducing elective surgery during the COVID-19 pandemic: modelling study

Background

The COVID-19 response required the cancellation of all but the most urgent surgical procedures. The number of cancelled surgical procedures owing to Covid-19, and the reintroduction of surgical acivirt, was modelled.

Methods

This was a modelling study using Hospital Episode Statistics data (2014–2019). Surgical procedures were grouped into four urgency classes. Expected numbers of surgical procedures performed between 1 March 2020 and 28 February 2021 were modelled. Procedure deficit was estimated using conservative assumptions and the gradual reintroduction of elective surgery from the 1 June 2020. Costs were calculated using NHS reference costs and are reported as millions or billions of euros. Estimates are reported with 95 per cent confidence intervals.

Results

A total of 547 534 (95 per cent c.i. 3 318 195 to 6 250 771) patients with a pooled mean age of 53.5 years were expected to undergo surgery between 1 March 2020 and 28 February 2021. By 31 May 2020, 749 247 (513 564 to 1 077 448) surgical procedures had been cancelled. Assuming that elective surgery is reintroduced gradually, 2 328 193 (1 483 834 – 3 450 043) patients will be awaiting surgery by 28 February 2021. The cost of delayed procedures is €5.3 (3.1 to 8.0) billion. Safe delivery of surgery during the pandemic will require substantial extra resources costing €526.8 (449.3 to 633.9) million.

Conclusion

As a consequence of the Covid-19 pandemic, provision of elective surgery will be delayed and associated with increased healthcare costs.

Emergency hospital admissions associated with non-communicable diseases 1998-2018 in England, Wales and Scotland: an ecological study

BACKGROUND

Non-communicable diseases (NCDs) are increasingly prevalent and were responsible for 40.5 million deaths (71%) globally in 2016. We examined the number of NCD-related emergency hospital admissions during the years 1998 to 2018 in the UK.

METHODS

Demographic features for those admitted as an emergency with NCDs as their primary diagnosis were collated for all admissions in England, Wales and Scotland. NCDs recorded as secondary diagnoses for all admissions in England from 2012 to 2018 were additionally recorded.

RESULTS

We identified 120,662,155 emergency episodes of care. From 1998 to 2018 there was an increase from 1,416,233 to 1,892,501 in annual emergency admissions due to NCDs. This, however, represented a fall in the proportion of NCD among all emergency admissions, from 33.4% to 26.9%. Mean age of all patients admitted increased from 46.3 to 53.8 years.

CONCLUSION

Despite a fall in proportion of NCD admissions, the population acutely admitted to hospital was increasingly elderly and increasingly comorbid.

Current use of inotropes in circulatory shock

Background

Treatment decisions on critically ill patients with circulatory shock lack consensus. In an international survey, we aimed to evaluate the indications, current practice, and therapeutic goals of inotrope therapy in the treatment of patients with circulatory shock.

Methods

From November 2016 to April 2017, an anonymous web-based survey on the use of cardiovascular drugs was accessible to members of the European Society of Intensive Care Medicine (ESICM). A total of 14 questions focused on the profile of respondents, the triggering factors, first-line choice, dosing, timing, targets, additional treatment strategy, and suggested effect of inotropes. In addition, a group of 42 international ESICM experts was asked to formulate recommendations for the use of inotropes based on 11 questions.

Results

A total of 839 physicians from 82 countries responded. Dobutamine was the first-line inotrope in critically ill patients with acute heart failure for 84% of respondents. Two-thirds of respondents (66%) stated to use inotropes when there were persistent clinical signs of hypoperfusion or persistent hyperlactatemia despite a supposed adequate use of fluids and vasopressors, with (44%) or without (22%) the context of low left ventricular ejection fraction. Nearly half (44%) of respondents stated an adequate cardiac output as target for inotropic treatment. The experts agreed on 11 strong recommendations, all of which were based on excellent (> 90%) or good (81–90%) agreement. Recommendations include the indications for inotropes (septic and cardiogenic shock), the choice of drugs (dobutamine, not dopamine), the triggers (low cardiac output and clinical signs of hypoperfusion) and targets (adequate cardiac output) and stopping criteria (adverse effects and clinical improvement).

Conclusion

Inotrope use in critically ill patients is quite heterogeneous as self-reported by individual caregivers. Eleven strong recommendations on the indications, choice, triggers and targets for the use of inotropes are given by international experts. Future studies should focus on consistent indications for inotrope use and implementation into a guideline for circulatory shock that encompasses individualized targets and outcomes.

Ethnicity and outcomes in patients hospitalised with COVID-19 infection in East London: an observational cohort study

OBJECTIVE

To describe outcomes within different ethnic groups of a cohort of hospitalised patients with confirmed COVID-19 infection. To quantify and describe the impact of a number of prognostic factors, including frailty and inflammatory markers.

SETTING

Five acute National Health Service Hospitals in east London.

DESIGN

Prospectively defined observational study using registry data.

PARTICIPANTS

1737 patients aged 16 years or over admitted to hospital with confirmed COVID-19 infection between 1 January and 13 May 2020.

MAIN OUTCOME MEASURES

The primary outcome was 30-day mortality from time of first hospital admission with COVID-19 diagnosis during or prior to admission. Secondary outcomes were 90-day mortality, intensive care unit (ICU) admission, ICU and hospital length of stay and type and duration of organ support. Multivariable survival analyses were adjusted for potential confounders.

RESULTS

1737 were included in our analysis of whom 511 had died by day 30 (29%). 538 (31%) were from Asian, 340 (20%) black and 707 (40%) white backgrounds. Compared with white patients, those from minority ethnic backgrounds were younger, with differing comorbidity profiles and less frailty. Asian and black patients were more likely to be admitted to ICU and to receive invasive ventilation (OR 1.54, (95% CI 1.06 to 2.23); p=0.023 and OR 1.80 (95% CI 1.20 to 2.71); p=0.005, respectively). After adjustment for age and sex, patients from Asian (HR 1.49 (95% CI 1.19 to 1.86); p<0.001) and black (HR 1.30 (95% CI 1.02 to 1.65); p=0.036) backgrounds were more likely to die. These findings persisted across a range of risk factor-adjusted analyses accounting for major comorbidities, obesity, smoking, frailty and ABO blood group.

CONCLUSIONS

Patients from Asian and black backgrounds had higher mortality from COVID-19 infection despite controlling for all previously identified confounders and frailty. Higher rates of invasive ventilation indicate greater acute disease severity. Our analyses suggest that patients of Asian and black backgrounds suffered disproportionate rates of premature death from COVID-19.

A restrictive versus liberal transfusion strategy to prevent myocardial injury in patients undergoing surgery for fractured neck of femur: a feasibility randomised trial (RESULT-NOF)

BACKGROUND

The optimum transfusion strategy in patients with fractured neck of femur is uncertain, particularly if there is coexisting cardiovascular disease.

METHODS

We conducted a prospective, single-centre, randomised feasibility trial of two transfusion strategies. We randomly assigned patients undergoing surgery for fractured neck of femur to a restrictive (haemoglobin, 70-90 g L-1) or liberal (haemoglobin, 90-110 g L-1) transfusion strategy throughout their hospitalisation. Feasibility outcomes included: enrolment rate, protocol compliance, difference in haemoglobin, and blood exposure. The primary clinical outcome was myocardial injury using troponin estimations. Secondary outcomes included major adverse cardiac events, postoperative complications, duration of hospitalisation, mortality, and quality of life.

RESULTS

We enrolled 200 (22%) of 907 eligible patients, and 62 (31%) showed decreased haemoglobin (to 90 g L-1 or less) and were thus exposed to the intervention. The overall protocol compliance was 81% in the liberal group and 64% in the restrictive group. Haemoglobin concentrations were similar preoperatively and at postoperative day 1 but lower in the restrictive group on day 2 (mean difference [MD], 7.0 g L-1; 95% confidence interval [CI], 1.6-12.4). Lowest haemoglobin within 30 days/before discharge was lower in the restrictive group (MD, 5.3 g L-1; 95% CI, 1.7-9.0). Overall, 58% of patients in the restrictive group received no transfusion compared with 4% in the liberal group (difference in proportion, 54.5%; 95% CI, 36.8-72.2). The proportion with the primary clinical outcome was 14/26 (54%, liberal) vs 24/34 (71%, restrictive), and the difference in proportion was -16.7% (95% CI, -41.3 to 7.8; P=0.18).

CONCLUSION

A clinical trial of two transfusion strategies in hip fracture with a clinically relevant cardiac outcome is feasible.

CLINICAL TRIAL REGISTRATION

NCT03407573.

Socioeconomic deprivation and long-term outcomes after elective surgery: analysis of prospective data from two observational studies

BACKGROUND

Socioeconomic deprivation is associated with health inequalities. We explored relationships between socioeconomic group and outcomes after elective surgery in the UK National Health Service (NHS).

METHODS

We combined data from two observational studies in 115 NHS hospitals and determined socioeconomic group using the Index of Multiple Deprivation (IMD) quintiles based on place of residence. Postoperative complications and 3-yr survival were assessed using logistic and Cox regression. Univariate analyses were adjusted for age differences between IMD quintiles. Multivariable analyses were used to account for other baseline risk factors including sex and comorbid disease. Results are reported as n (%), hazard ratios (HR) or odds ratios (OR) with 95% confidence intervals.

RESULTS

Postoperative complications developed in 971/9051 patients (10.7%) and 1597/9043 patients (17.7%) died within 3 yr. Complication rates increased with deprivation (reference group least-deprived IMD5): IMD1 (OR=1.44 [1.17-1.78]; P<0.001), IMD2 (OR=1.38 [1.12-1.70]; P<0.01), IMD3 (OR=1.09 [0.88-1.35]: P=0.44), IMD4 (OR=0.89 [0.71-1.11]; P=0.30). More patients from the most deprived quintile died (IMD1) (n=349, 18.8%) compared with the least deprived (IMD5) (n=297, 15.9%) with a trend across the socioeconomic spectrum (P=0.01). After age adjustment, patients in the most deprived areas experienced reduced 3-yr survival: IMD1 (HR=1.43 [1.23-1.67]; P<0.0001), IMD2 (HR=1.35 [1.15-1.57]; P<0.001), IMD3 (HR=1.04 [0.89-1.23]; P=0.60), and IMD4 (HR=1.11 [0.95-1.30]; P=0.19). This finding persisted in risk-adjusted analyses. Increased complication rates only partially explained this reduced survival.

CONCLUSIONS

Socioeconomic deprivation is associated with worse long-term outcomes after elective surgery. This risk factor should be considered when planning perioperative care for patients from deprived areas.

MicroRNA signatures of perioperative myocardial injury after elective noncardiac surgery: a prospective observational mechanistic cohort study

BACKGROUND

Elevated plasma or serum troponin, indicating perioperative myocardial injury (PMI), is common after noncardiac surgery. However, underlying mechanisms remain unclear. Acute coronary syndrome (ACS) is associated with the early appearance of circulating microRNAs, which regulate post-translational gene expression. We hypothesised that if PMI and ACS share pathophysiological mechanisms, common microRNA signatures should be evident.

METHODS

We performed a nested case control study of samples obtained before and after noncardiac surgery from patients enrolled in two prospective observational studies of PMI (postoperative troponin I/T>99th centile). In cohort one, serum microRNAs were compared between patients with or without PMI, matched for age, gender, and comorbidity. Real-time polymerase chain reaction quantified (qRT-PCR) relative microRNA expression (cycle quantification [Cq] threshold <37) before and after surgery for microRNA signatures associated with ACS, blinded to PMI. In cohort two, we analysed (EdgeR) microRNA from plasma extracellular vesicles using next-generation sequencing (Illumina HiSeq 500). microRNA-messenger RNA-function pathway analysis was performed (DIANA miRPath v3.0/TopGO).

RESULTS

MicroRNAs were detectable in all 59 patients (median age 67 yr [61-75]; 42% male), who had similar clinical characteristics independent of developing PMI. In cohort one, serum microRNA expression increased after surgery (mean fold-change) hsa-miR-1-3p: 3.99 (95% confidence interval [CI: 1.95-8.19]; hsa-miR-133-3p: 5.67 [95% CI: 2.94-10.91]; P<0.001). These changes were not associated with PMI. Bioinformatic analysis of differentially expressed microRNAs from cohorts one (n=48) and two (n=11) identified pathways associated with adrenergic stress and calcium dysregulation, rather than ischaemia.

CONCLUSIONS

Circulating microRNAs associated with cardiac ischaemia were universally elevated in patients after surgery, independent of development of myocardial injury.