Sex-based differences in short- and longer-term diet-induced metabolic heart disease.

Sex-based differences in the development of obesity-induced cardiometabolic dysfunction are well documented, however, the specific mechanisms are not completely understood. Obesity has been linked to dysregulation of the epitranscriptome, but the role of N6-methyladenosine (m6A) RNA methylation has not been investigated in relation to the sex differences during obesity-induced cardiac dysfunction. In the current study, male and female C57BL/6J mice were subjected to short- and long-term high-fat/high-sucrose (HFHS) diet to induce obesogenic stress. Cardiac echocardiography showed males developed systolic and diastolic dysfunction after 4 mo of diet, but females maintained normal cardiac function despite both sexes being metabolically dysfunctional. Cardiac m6A machinery gene expression was differentially regulated by duration of HFHS diet in male, but not female mice, and left ventricular ejection fraction correlated with RNA machinery gene levels in a sex- and age-dependent manner. RNA-sequencing of cardiac transcriptome revealed that females, but not males may undergo protective cardiac remodeling early in the course of obesogenic stress. Taken together, our study demonstrates for the first time that cardiac RNA methylation machinery genes are regulated early during obesogenic stress in a sex-dependent manner and may play a role in the sex differences observed in cardiometabolic dysfunction.NEW & NOTEWORTHY Sex differences in obesity-associated cardiomyopathy are well documented but incompletely understood. We show for the first time that RNA methylation machinery genes may be regulated in response to obesogenic diet in a sex- and age-dependent manner and levels may correspond to cardiac systolic function. Our cardiac RNA-seq analysis suggests female, but not male mice may be protected from cardiac dysfunction by a protective cardiac remodeling response early during obesogenic stress.

The Effect of Lower Tidal Volume Ventilation Facilitated by Extracorporeal Carbon Dioxide Removal Compared With Conventional Lung Protective Ventilation on Cardiac Function.

OBJECTIVES: Lower tidal volume ventilation (targeting 3 mL/kg predicted body weight, PBW) facilitated by extracorporeal carbon dioxide removal (ECCO2R) has been investigated as a potential therapy for acute hypoxemic respiratory failure (AHRF) in the pRotective vEntilation with veno-venouS lung assisT in respiratory failure (REST) trial. We investigated the effect of this strategy on cardiac function, and in particular the right ventricle. DESIGN: Substudy of the REST trial. SETTING: Nine U.K. ICUs. PATIENTS: Patients with AHRF (Pao2/Fio2 < 150 mm Hg [20 kPa]). INTERVENTION: Transthoracic echocardiography and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements were collected at baseline and postrandomization in patients randomized to ECCO2R or usual care. MEASUREMENTS: The primary outcome measures were a difference in tricuspid annular plane systolic excursion (TAPSE) on postrandomization echocardiogram and difference in NT-proBNP postrandomization. RESULTS: There were 21 patients included in the echocardiography cohort (ECCO2R, n = 13; usual care, n = 8). Patient characteristics were similar in both groups at baseline. Median (interquartile range) tidal volumes were lower in the ECCO2R group compared with the usual care group postrandomization; 3.6 (3.1-4.2) mL/kg PBW versus 5.2 (4.9-5.7) mL/kg PBW, respectively (p = 0.01). There was no difference in the primary outcome measure of mean (sd) TAPSE in the ECCO2R and usual care groups postrandomization; 21.3 (5.4) mm versus 20.1 (3.2) mm, respectively (p = 0.60). There were 75 patients included in the NT-proBNP cohort (ECCO2R, n = 36; usual care, n = 39). Patient characteristics were similar in both groups at baseline. Median (interquartile range [IQR]) tidal volumes were lower in the ECCO2R group than the usual care group postrandomization; 3.8 (3.3-4.2) mL/kg PBW versus 6.7 (5.8-8.1) mL/kg PBW, respectively (p < 0.0001). There was no difference in median (IQR) NT-proBNP postrandomization; 1121 (241-5370) pg/mL versus 1393 (723-4332) pg/mL in the ECCO2R and usual care groups, respectively (p = 0.30). CONCLUSIONS: In patients with AHRF, a reduction in tidal volume facilitated by ECCO2R, did not modify cardiac function.

Elevated ferritin, mediated by IL-18 is associated with systemic inflammation and mortality in acute respiratory distress syndrome (ARDS).

BACKGROUND: Inflammatory subphenotypes have been identified in acute respiratory distress syndrome (ARDS). Hyperferritinaemia in sepsis is associated with hyperinflammation, worse clinical outcomes, and may predict benefit with immunomodulation. Our aim was to determine if raised ferritin identified a subphenotype in patients with ARDS. METHODS: Baseline plasma ferritin concentrations were measured in patients with ARDS from two randomised controlled trials of simvastatin (Hydroxymethylglutaryl-CoA Reductase Inhibition with Simvastatin in Acute Lung Injury to Reduce Pulmonary Dysfunction-2 (HARP-2); discovery cohort, UK) and neuromuscular blockade (ROSE; validation cohort, USA). Results were analysed using a logistic regression model with restricted cubic splines, to determine the ferritin threshold associated with 28-day mortality. RESULTS: Ferritin was measured in 511 patients from HARP-2 (95% of patients enrolled) and 847 patients (84% of patients enrolled) from ROSE. Ferritin was consistently associated with 28-day mortality in both studies and following a meta-analysis, a log-fold increase in ferritin was associated with an OR 1.71 (95% CI 1.01 to 2.90) for 28-day mortality. Patients with ferritin >1380 ng/mL (HARP-2 28%, ROSE 24%) had a significantly higher 28-day mortality and fewer ventilator-free days in both studies. Mediation analysis, including confounders (acute physiology and chronic health evaluation-II score and ARDS aetiology) demonstrated a statistically significant contribution of interleukin (IL)-18 as an intermediate pathway between ferritin and mortality. CONCLUSIONS: Ferritin is a clinically useful biomarker in ARDS and is associated with worse patient outcomes. These results provide support for prospective interventional trials of immunomodulatory agents targeting IL-18 in this hyperferritinaemic subgroup of patients with ARDS.

PIM-COVID study: protocol for a multicentre, longitudinal study measuring the psychological impact of surviving an intensive care admission due to COVID-19 on patients in the UK.

INTRODUCTION: Psychological distress is common in intensive care unit (ICU) survivors and is anticipated in those who were treated for severe COVID-19 infection. This trainee-led, multicentre, observational, longitudinal study aims to assess the psychological outcomes of ICU survivors treated for COVID-19 infection in the UK at 3, 6 and/or 12 months after ICU discharge and explore whether there are demographic, psychosocial and clinical risk factors for psychological distress. METHODS AND ANALYSIS: Questionnaires will be provided to study participants 3, 6 and/or 12 months after discharge from intensive care, assessing for anxiety, depression, post-traumatic stress symptoms, health-related quality of life and physical symptoms. Demographic, psychosocial and clinical data will also be collected to explore risk factors for psychological distress using latent growth curve modelling. Study participants will be eligible to complete questionnaires at any of the three time points online, by telephone or by post. ETHICS AND DISSEMINATION: The PIM-COVID study was approved by the Health Research Authority (East Midlands - Derby Research and Ethics Committee, reference: 20/EM/0247). TRIAL REGISTRATION NUMBER: NCT05092529.

Fibulin-3 is necessary to prevent cardiac rupture following myocardial infarction.

Despite the high prevalence of heart failure in the western world, there are few effective treatments. Fibulin-3 is a protein involved in extracellular matrix (ECM) structural integrity, however its role in the heart is unknown. We have demonstrated, using single cell RNA-seq, that fibulin-3 was highly expressed in quiescent murine cardiac fibroblasts, with expression highest prior to injury and late post-infarct (from ~ day-28 to week-8). In humans, fibulin-3 was upregulated in left ventricular tissue and plasma of heart failure patients. Fibulin-3 knockout (Efemp1-/-) and wildtype mice were subjected to experimental myocardial infarction. Fibulin-3 deletion resulted in significantly higher rate of cardiac rupture days 3-6 post-infarct, indicating a weak and poorly formed scar, with severe ventricular remodelling in surviving mice at day-28 post-infarct. Fibulin-3 knockout mice demonstrated less collagen deposition at day-3 post-infarct, with abnormal collagen fibre-alignment. RNA-seq on day-3 infarct tissue revealed upregulation of ECM degradation and inflammatory genes, but downregulation of ECM assembly/structure/organisation genes in fibulin-3 knockout mice. GSEA pathway analysis showed enrichment of inflammatory pathways and a depletion of ECM organisation pathways. Fibulin-3 originates from cardiac fibroblasts, is upregulated in human heart failure, and is necessary for correct ECM organisation/structural integrity of fibrotic tissue to prevent cardiac rupture post-infarct.

Association of Circulating Plasma Secreted Frizzled-Related Protein 5 (Sfrp5) Levels with Cardiac Function.

Secreted frizzled-related protein 5 (SFRP5) is a novel anti-inflammatory adipokine that may play a role in cardiovascular development and disease. However, there is yet to be a comprehensive investigation into whether circulating SFRP5 can be a biomarker for cardiac function. Plasma SFRP5 levels were measured via ELISA in 262 patients admitted to a cardiology unit. Plasma SFRP5 levels were significantly lower in patients with a history of heart failure (HF), coronary artery disease (CAD), and atrial fibrillation (AF; p = 0.001). In univariate analyses, SFRP5 levels were also significantly positively correlated with left ventricular ejection fraction (LVEF) (r = 0.52, p < 0.001) and negatively correlated with E/E' (r = -0.30, p < 0.001). Patients with HF, CAD, low LVEF, low triglycerides, high CRP, and high eGFR were associated with lower SFRP5 levels independent of age, BMI, or diabetes after multivariate analysis (overall model r = 0.729, SE = 0.638). Our results show that low plasma SFRP5 levels are independently associated with the presence of HF, CAD, and, importantly, impaired LV function. These results suggest a potential role of SFRP5 as a biomarker, as well as a mediator of cardiac dysfunction independent of obesity and metabolic regulation.

Mind The Gap, Aboriginal and Torres Strait Islander Cardiovascular Health: A Narrative Review.

Australia's First Nations Peoples, Aboriginal and Torres Strait Islanders, have reduced life expectancy compared to the wider community. Cardiovascular diseases, mainly driven by ischaemic heart disease, are the leading contributors to this disparity. Despite over a third of First Nations Peoples living in New South Wales, the bulk of the peer-reviewed literature is from Central Australia and Far North Queensland. Regardless of the site of publication, First Nations Peoples are significantly younger at disease onset and have higher rates of comorbidities, in turn driving adverse health events. On top of this, very few First Nations Peoples specific cardiovascular interventions or programs have been shown to improve outcomes. The traditional biomedical model of care is less efficacious and non-traditional models of communication such as clinical yarning may benefit both clinicians and patients. The key purpose of this review is to highlight the deficiencies of our knowledge of cardiovascular burden of disease for First Nations Peoples; and to serve as a catalyst for more dedicated research. We need to have relationships with communities and concentrate on community improvement and partnerships. By involving First Nations Peoples researchers in collaboration with local communities in all levels of health care design and intervention will improve outcomes.

Acute hypoxaemic respiratory failure after treatment with lower tidal volume ventilation facilitated by extracorporeal carbon dioxide removal: long-term outcomes from the REST randomised trial.

INTRODUCTION: Lower tidal volume ventilation, facilitated by veno-venous extracorporeal carbon dioxide removal (vv-ECCO2R), does not improve 90-day mortality in patients with acute hypoxaemic respiratory failure (AHRF). The aim of this analysis was to evaluate the effect of this therapeutic strategy on long-term outcomes. METHODS: This was a prespecified analysis of the REST trial, a UK-wide multicentre randomised clinical trial that compared lower tidal volume ventilation, facilitated by vv-ECCO2R (intervention), with standard care in the treatment of patients with moderate-to-severe AHRF. Mortality to 2 years was assessed, while respiratory function, post-traumatic stress disorder, cognitive function and health-related quality of life were evaluated in survivors at 1 year using standardised questionnaires. RESULTS: Of 412 patients enrolled into the REST trial, 391 (95%) had 2-year mortality outcome data available. There was no difference in the time to death between intervention and standard care (HR 1.08 (0.81, 1.44); log-rank test p=0.61). 161 patients alive at 1 year provided at least one questionnaire response. There was no difference in respiratory function, post-traumatic stress disorder, cognitive dysfunction or health-related quality of life between patients allocated to intervention or standard care. CONCLUSION: Lower-tidal volume ventilation facilitated by vv-ECCO2R does not affect 1-year mortality in patients with moderate-to-severe AHRF. Of the patients who provided questionnaire responses, there was no treatment effect on long-term respiratory function, post-traumatic stress disorder, cognitive dysfunction or health-related quality of life. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT02654327.

Extracellular Matrix Protein-1 as a Mediator of Inflammation-Induced Fibrosis After Myocardial Infarction.

Irreversible fibrosis is a hallmark of myocardial infarction (MI) and heart failure. Extracellular matrix protein-1 (ECM-1) is up-regulated in these hearts, localized to fibrotic, inflammatory, and perivascular areas. ECM-1 originates predominantly from fibroblasts, macrophages, and pericytes/vascular cells in uninjured human and mouse hearts, and from M1 and M2 macrophages and myofibroblasts after MI. ECM-1 stimulates fibroblast-to-myofibroblast transition, up-regulates key fibrotic and inflammatory pathways, and inhibits cardiac fibroblast migration. ECM-1 binds HuCFb cell surface receptor LRP1, and LRP1 inhibition blocks ECM-1 from stimulating fibroblast-to-myofibroblast transition, confirming a novel ECM-1-LRP1 fibrotic signaling axis. ECM-1 may represent a novel mechanism facilitating inflammation-fibrosis crosstalk.

Remote monitoring in patients with heart failure with cardiac implantable electronic devices: a systematic review and meta-analysis.

BACKGROUND: Remote monitoring (RM) of cardiac implantable electronic devices (CIEDs) is now the standard of care, but whether the demonstrated benefits of RM translate into improvements in heart failure (HF) management is controversial. This systematic review addresses the role of RM in patients with HF with a CIED. METHODS AND RESULTS: A systematic search of the literature for randomised clinical trials in patients with HF and a CIED assessing efficacy/effectiveness of RM was performed using MEDLINE, PubMed and Embase. Meta-analysis was performed on the effects of RM of CIEDs in patients with HF on mortality and readmissions. Effects on implantable cardiac defibrillator (ICD) therapy, healthcare costs and clinic presentations were also assessed.607 articles were identified and refined to 10 studies with a total of 6579 patients. Implementation of RM was not uniform with substantial variation in methodology across the studies. There was no reduction in mortality or hospital readmission rates, while ICD therapy findings were inconsistent. There was a reduction in patient-associated healthcare costs and reduction in healthcare presentations. CONCLUSION: RM for patients with CIEDs and HF was not uniformly performed. As currently implemented, RM does not provide a benefit on overall mortality or the key metric of HF readmission. It does provide a reduction in healthcare costs and healthcare presentations. PROSPERO REGISTRATION NUMBER: CRD42019129270.

Extracorporeal carbon dioxide removal in acute hypoxaemic respiratory failure: a systematic review, Bayesian meta-analysis and trial sequential analysis.

PURPOSE: To assess the safety and efficacy of extracorporeal carbon dioxide removal (ECCO2R) versus standard care in patients with acute hypoxaemic respiratory failure (AHRF). METHODS: MEDLINE, Embase and clinical trial registries were searched from 1994 to 31 December 2021. We included randomised controlled trials (RCTs) and observational studies. Pairs of reviewers independently extracted data and assessed the risk of bias. The primary outcome was mortality. Secondary outcomes included ventilator-free days, length of stay, safety and adverse events and physiological changes. As a primary analysis, we performed a meta-analysis of mortality until day 30 using a Bayesian random effects model. We then performed a trial sequential analysis of RCTs. RESULTS: 21 studies met inclusion criteria: three RCTs, enrolling 531 patients, and 18 observational studies. In a pooled analysis of RCTs, the posterior probability of increased mortality with the use of ECCO2R was 73% (relative risk 1.19, 95% credible interval 0.70-2.29). There was substantial heterogeneity in the reporting of safety and adverse events. However, the incidence of extra and intracranial haemorrhage was higher (relative risk 3.00, 95% credible interval 0.41-20.51) among those randomised to ECCO2R. Current trials have accumulated 80.8% of the diversity-adjusted required information size and the lack of effect reaches futility for a 10% absolute risk reduction in mortality. CONCLUSIONS: The use of ECCO2R in patients with AHRF is not associated with improvements in clinical outcomes. Furthermore, it is likely that further trials of ECCO2R aiming to achieve an absolute risk reduction in mortality of ≥10% are futile.

Paracrine Factors Released by Stem Cells of Mesenchymal Origin and their Effects in Cardiovascular Disease: A Systematic Review of Pre-clinical Studies.

Mesenchymal stem cell (MSC) therapy has gained significant traction in the context of cardiovascular repair, and have been proposed to exert their regenerative effects via the secretion of paracrine factors. In this systematic review, we examined the literature and consolidated available evidence for the "paracrine hypothesis". Two Ovid SP databases were searched using a strategy encompassing paracrine mediated MSC therapy in the context of ischemic heart disease. This yielded 86 articles which met the selection criteria for inclusion in this study. We found that the MSCs utilized in these articles were primarily derived from bone marrow, cardiac tissue, and adipose tissue. We identified 234 individual protective factors across these studies, including VEGF, HGF, and FGF2; which are proposed to exert their effects in a paracrine manner. The data collated in this systematic review identifies secreted paracrine factors that could decrease apoptosis, and increase angiogenesis, cell proliferation, and cell viability. These included studies have also demonstrated that the administration of MSCs and indirectly, their secreted factors can reduce infarct size, and improve left ventricular ejection fraction, contractility, compliance, and vessel density. Furthering our understanding of the way these factors mediate repair could lead to the identification of therapeutic targets for cardiac regeneration.

Management of Acute Coronary Syndromes in Patients in Rural Australia: The MORACS Randomized Clinical Trial.

Importance: Treatment of ST-segment elevation myocardial infarction (STEMI) in rural settings involves thrombolysis followed by transfer to a percutaneous coronary intervention-capable hospital. The first step is accurate diagnosis via electrocardiography (ECG), but one-third of all STEMI incidents go unrecognized and hence untreated. Objective: To reduce missed diagnoses of STEMI. Design, Setting, and Participants: This cluster randomized clinical trial included 29 hospital emergency departments (EDs) in rural Australia with no emergency medicine specialists, which were randomized to usual care vs automatically triggered diagnostic support from the tertiary referral hospital (management of rural acute coronary syndromes [MORACS] intervention). Patients presenting with symptoms compatible with acute coronary syndromes (ACS) were eligible for inclusion. The study was conducted from December 2018 to April 2020. Data were analyzed in August 2021. Intervention: Triage of a patient with symptoms compatible with ACS triggered an automated notification to the tertiary hospital coronary care unit. The ECG and point-of-care troponin results were reviewed remotely and a phone call was made to the treating physician in the rural hospital to assist with diagnosis and initiation of treatment. Main Outcomes and Measures: The proportion of patients with missed STEMI diagnoses. Results: A total of 6249 patients were included in the study (mean [SD] age, 63.6 [12.2] years; 48% female). Of 7474 ED presentations with suspected ACS, STEMI accounted for 77 (2.0%) in usual care hospitals and 46 (1.3%) in MORACS hospitals. Missed diagnosis of STEMI occurred in 27 of 77 presentations (35%) in usual care hospitals and 0 of 46 (0%) in MORACS hospitals (P < .001). Of eligible patients, 48 of 75 (64%) in the usual care group and 36 of 36 (100%) in the MORACS group received primary reperfusion (P < .001). In the usual care group, 12-month mortality was 10.3% (n = 8) vs 6.5% (n = 3) in the MORACS group (relative risk, 0.64; 95% CI, 0.18-2.23). Patients with missed STEMI diagnoses had a mortality of 25.9% (n = 7) compared with 2.0% (n = 1) for those with accurately diagnosed STEMI (relative risk, 13.2; 95% CI, 1.71-102.00; P = .001). Overall, there were 6 patients who did not have STEMI as a final diagnosis; 5 had takotsubo cardiomyopathy and 1 had pericarditis. There was no difference between groups in the rate of alternative final diagnosis. Conclusion and Relevance: The findings indicate that MORACS diagnostic support service reduced the proportion of missed STEMI and improved the rates of primary reperfusion therapy. Accurate diagnosis of STEMI was associated with lower mortality. Trial Registration: anzctr.org.au Identifier: ACTRN12619000533190.

Patient characteristics, short-term and long-term outcomes after incident heart failure admissions in a regional Australian setting.

AIMS: This study aims to (1) define the characteristics of patients with a first admission for heart failure (HF), stratified by type (reduced (HFrEF) vs preserved (HFpEF) ejection fraction) in a regional Australian setting; (2) compare the outcomes in terms of mortality and rehospitalisation and (3) assess adherence to the treatment guidelines. METHODS: We identified all index hospitalisations with HF to John Hunter Hospital and Tamworth Rural Referral Hospital in the Hunter New England Local Health District over a 12 months. We used the recent Australian HF guidelines to classify HFrEF and HFpEF and assess adherence to guideline-directed therapy. The primary outcome of the study was to compare short-term (1 year) and long-term all-cause mortality and the composite of all-cause hospitalisation or all-cause mortality of patients with HFrEF and HFpEF. RESULTS: There were 664 patients who had an index HF admission to John Hunter and Tamworth hospitals in 2014. The median age was 80 years, 47% were female and 22 (3%) were Aboriginal. In terms of HF type, 29% had HFrEF, 37% had HFpEF, while the remainder (34%) did not have an echocardiogram within 1 year of admission and could not be classified. The median follow-up was 3.3 years. HFrEF patients were predominantly male (64%) and in 48% the aetiology was ischaemic heart disease. The 1-year all-cause mortality was 23% in HFpEF subgroup and 29% in HFrEF subgroup (p=0.15). Five-year mortality was 61% in HFpEF and HFrEF patients. Of the HFrEF patients, only 61% were on renin-angiotensin-aldosterone blockers, 74% were on ß-blockers and 39% were on aldosterone antagonist. CONCLUSION: HF patients are elderly and about evenly split between HFrEF and HFpEF. In this regional cohort, both HF types are associated with similar 1-year and 5-year mortality following incident HF hospitalisation. Echocardiography and guideline-directed therapies were underused.

Aspirin as a Treatment for ARDS: A Randomized, Placebo-Controlled Clinical Trial.

BACKGROUND: There is no pharmacologic treatment for ARDS. Platelets play an important role in the pathophysiology of ARDS. Preclinical, observational, and clinically relevant models of ARDS indicate aspirin as a potential therapeutic option. RESEARCH QUESTION: Is enteral aspirin (75 mg, once daily) safe and effective in improving surrogate outcomes in adult patients with ARDS? STUDY DESIGN AND METHODS: This randomized, double-blind (patient and investigator), allocation-concealed, placebo-controlled phase 2 trial was conducted in five UK ICUs. Patients fulfilling the Berlin definition of ARDS were randomly assigned at a 1:1 ratio to receive enteral aspirin (75 mg) or placebo, for a maximum of 14 days, using a computer-generated randomization schedule, with variable block size, stratified by vasopressor requirement. The primary end point was oxygenation index (OI) on day 7. Secondary outcomes included safety parameters and other respiratory physiological markers. Analyses were by intention to treat. RESULTS: The trial was stopped early, due to slow recruitment, after 49 of a planned 60 patients were recruited. Twenty-four patients were allocated to aspirin and 25 to placebo. There was no significant difference in day 7 OI [aspirin group: unadjusted mean, 54.4 (SD 26.8); placebo group: 42.4 (SD 25); mean difference, 12.0; 95% CI, -6.1 to 30.1; P = .19]. Aspirin did not significantly impact the secondary outcomes. There was no difference in the number of adverse events between the groups (13 in each; OR, 1.04; 95% CI, 0.56-1.94; P = .56). INTERPRETATION: Aspirin was well tolerated but did not improve OI or other physiological outcomes; a larger trial is not feasible in its current design. TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT02326350; URL: www. CLINICALTRIALS: gov.

Feasibility of conservative fluid administration and deresuscitation compared with usual care in critical illness: the Role of Active Deresuscitation After Resuscitation-2 (RADAR-2) randomised clinical trial.

PURPOSE: Fluid overload is common in critical illness and is associated with mortality. This study investigated the feasibility of a randomised trial comparing conservative fluid administration and deresuscitation (active removal of accumulated fluid using diuretics or ultrafiltration) with usual care in critical illness. METHODS: Open-label, parallel-group, allocation-concealed randomised clinical feasibility trial. Mechanically ventilated adult patients expected to require critical care beyond the next calendar day were enrolled between 24 and 48 h following admission to the intensive care unit (ICU). Patients were randomised to either a 2-stage fluid strategy comprising conservative fluid administration and, if fluid overload was present, active deresuscitation, or usual care. The primary endpoint was fluid balance in the 24 h up to the start of study day 3. Secondary endpoints included cumulative fluid balance, mortality, and duration of mechanical ventilation. RESULTS: One hundred and eighty patients were randomised. After withdrawal of 1 patient, 89 patients assigned to the intervention were compared with 90 patients assigned to the usual care group. The mean plus standard deviation (SD) 24-h fluid balance up to study day 3 was lower in the intervention group (- 840 ± 1746 mL) than the usual care group (+ 130 ± 1401 mL; P < 0.01). Cumulative fluid balance was lower in the intervention group at days 3 and 5. Overall, clinical outcomes did not differ significantly between the two groups, although the point estimate for 30-day mortality favoured the usual care group [intervention arm: 19 of 90 (21.6%) versus usual care: 14 of 89 (15.6%), P = 0.32]. Baseline imbalances between groups and lack of statistical power limit interpretation of clinical outcomes. CONCLUSIONS: A strategy of conservative fluid administration and active deresuscitation is feasible, reduces fluid balance compared with usual care, and may cause benefit or harm. In view of wide variations in contemporary clinical practice, large, adequately powered trials investigating the clinical effectiveness of conservative fluid strategies in critically ill patients are warranted.

Hyperoxaemia and hypoxaemia are associated with harm in patients with ARDS.

BACKGROUND: Oxygen therapy is routinely administered to mechanically ventilated patients. However, there remains uncertainty about the optimal oxygen titration target in patients with the acute respiratory distress syndrome (ARDS). METHODS: Prospectively identified adult patients meeting the Berlin definition of ARDS between 1st January 2014 and 13th December 2016 were analyzed. Oxygen exposure variables were collected at 6-hourly intervals. The primary exposure was the average time-weighted partial pressure of arterial oxygen (PaO2) calculated over a maximum of 7 days from meeting ARDS criteria. The primary outcome was ICU mortality. Univariable and multivariable logistic regression analyses were performed to assess the impact of exposure variables on clinical outcomes. Results are presented as odds ratio [95% confidence interval]. RESULTS: 202 patients were included in the final analysis. Overall ICU mortality was 31%. The average time-weighted PaO2 during the first 7 days of ARDS was similar between non-survivors and survivors (11.3 kPa [10.2, 12.5] (84.8 mmHg [76.5, 93.8]) vs. 11.9 kPa [10.9, 12.6] (89.3 mmHg [81.8, 94.5]); p = 0.08). In univariable and multivariable analysis, average time-weighted PaO2 demonstrated a U-shaped relationship with ICU mortality. There was a similar relationship identified with hospital mortality. CONCLUSIONS: In patients with ARDS, the predicted probability of both ICU and hospital mortality was lowest when the average time-weighted PaO2 was between 12.5 and 14 kPa (93.8-105.0 mmHg), suggesting this is a reasonable oxygenation target for clinicians to aim for.

Effect of Lower Tidal Volume Ventilation Facilitated by Extracorporeal Carbon Dioxide Removal vs Standard Care Ventilation on 90-Day Mortality in Patients With Acute Hypoxemic Respiratory Failure: The REST Randomized Clinical Trial.

Importance: In patients who require mechanical ventilation for acute hypoxemic respiratory failure, further reduction in tidal volumes, compared with conventional low tidal volume ventilation, may improve outcomes. Objective: To determine whether lower tidal volume mechanical ventilation using extracorporeal carbon dioxide removal improves outcomes in patients with acute hypoxemic respiratory failure. Design, Setting, and Participants: This multicenter, randomized, allocation-concealed, open-label, pragmatic clinical trial enrolled 412 adult patients receiving mechanical ventilation for acute hypoxemic respiratory failure, of a planned sample size of 1120, between May 2016 and December 2019 from 51 intensive care units in the UK. Follow-up ended on March 11, 2020. Interventions: Participants were randomized to receive lower tidal volume ventilation facilitated by extracorporeal carbon dioxide removal for at least 48 hours (n = 202) or standard care with conventional low tidal volume ventilation (n = 210). Main Outcomes and Measures: The primary outcome was all-cause mortality 90 days after randomization. Prespecified secondary outcomes included ventilator-free days at day 28 and adverse event rates. Results: Among 412 patients who were randomized (mean age, 59 years; 143 [35%] women), 405 (98%) completed the trial. The trial was stopped early because of futility and feasibility following recommendations from the data monitoring and ethics committee. The 90-day mortality rate was 41.5% in the lower tidal volume ventilation with extracorporeal carbon dioxide removal group vs 39.5% in the standard care group (risk ratio, 1.05 [95% CI, 0.83-1.33]; difference, 2.0% [95% CI, -7.6% to 11.5%]; P = .68). There were significantly fewer mean ventilator-free days in the extracorporeal carbon dioxide removal group compared with the standard care group (7.1 [95% CI, 5.9-8.3] vs 9.2 [95% CI, 7.9-10.4] days; mean difference, -2.1 [95% CI, -3.8 to -0.3]; P = .02). Serious adverse events were reported for 62 patients (31%) in the extracorporeal carbon dioxide removal group and 18 (9%) in the standard care group, including intracranial hemorrhage in 9 patients (4.5%) vs 0 (0%) and bleeding at other sites in 6 (3.0%) vs 1 (0.5%) in the extracorporeal carbon dioxide removal group vs the control group. Overall, 21 patients experienced 22 serious adverse events related to the study device. Conclusions and Relevance: Among patients with acute hypoxemic respiratory failure, the use of extracorporeal carbon dioxide removal to facilitate lower tidal volume mechanical ventilation, compared with conventional low tidal volume mechanical ventilation, did not significantly reduce 90-day mortality. However, due to early termination, the study may have been underpowered to detect a clinically important difference. Trial Registration: ClinicalTrials.gov Identifier: NCT02654327.

Natural history and prognostic implications of left ventricular end-diastolic pressure in reperfused ST-segment elevation myocardial infarction: an analysis of the thrombolysis in myocardial infarction (TIMI) II randomized controlled trial.

BACKGROUND: The aim of the current study is to assess the natural history and prognostic value of elevated left ventricular end-diastolic pressure (LVEDP) in patients with ST-segment elevation myocardial infarction (STEMI) after reperfusion with thrombolysis; we utilize data from the Thrombolysis in Myocardial Infarction (TIMI) II study. METHODS: A total of 3339 patients were randomized to either an invasive (n = 1681) or a conservative (n = 1658) strategy in the TIMI II study following thrombolysis. To make the current cohort as relevant as possible to modern pharmaco-invasively managed cohorts, patients in the invasive arm with TIMI flow grade ≥ 2 (N = 1201) at initial catheterization are included in the analysis. Of these, 259 patients had a second catheterization prior to hospital discharge, and these were used to define the natural history of LVEDP in reperfused STEMI. RESULTS: The median LVEDP for the whole cohort was 18 mmHg (IQR: 12-23). Patients were divided into quartiles by LVEDP measured during the first cardiac catheterization. During a median follow up of 3 (IQR: 2.1-3.2) years, quartile 4 (highest LVEDP) had the highest incidence of mortality and heart failure admissions. In the cohort with paired catheterization data, the LVEDP dropped slightly from 18 mmHg (1QR: 12-22) to 15 mmHg (IQR: 10-20) (p = 0.01) from the first to the pre-hospital discharge catheterization. CONCLUSIONS: LVEDP remains largely stable during hospitalisation post-STEMI. Elevated LVEDP is a predictor of death and heart failure hospitalization in STEMI patients undergoing successful thrombolysis.