Sophie Wallace

Stopping vs. Continuing Aspirin before Coronary Artery Surgery

BACKGROUND Most patients with coronary artery disease receive aspirin for primary or secondary prevention of myocardial infarction, stroke, and death. Aspirin poses a risk of bleeding in patients undergoing surgery, but it is unclear whether aspirin should be stopped before coronary artery surgery. METHODS We used a 2-by-2 factorial trial design to randomly assign patients who were scheduled to undergo coronary artery surgery and were at risk for perioperative complications to receive aspirin or placebo and tranexamic acid or placebo. The results of the aspirin trial are reported here. Patients were randomly assigned to receive 100 mg of aspirin or matched placebo preoperatively. The primary outcome was a composite of death and thrombotic complications (nonfatal myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) within 30 days after surgery. RESULTS Among 5784 eligible patients, 2100 were enrolled; 1047 were randomly assigned to receive aspirin and 1053 to receive placebo. A primary outcome event occurred in 202 patients in the aspirin group (19.3%) and in 215 patients in the placebo group (20.4%) (relative risk, 0.94; 95% confidence interval, 0.80 to 1.12; P=0.55). Major hemorrhage leading to reoperation occurred in 1.8% of patients in the aspirin group and in 2.1% of patients in the placebo group (P=0.75), and cardiac tamponade occurred at rates of 1.1% and 0.4%, respectively (P=0.08). CONCLUSIONS Among patients undergoing coronary artery surgery, the administration of preoperative aspirin resulted in neither a lower risk of death or thrombotic complications nor a higher risk of bleeding than that with placebo. (Funded by the Australian National Health and Medical Research Council and others; Australia New Zealand Clinical Trials Registry number, ACTRN12605000557639.).

Tranexamic Acid in Patients Undergoing Coronary-Artery Surgery

Background Tranexamic acid reduces the risk of bleeding among patients undergoing cardiac surgery, but it is unclear whether this leads to improved outcomes. Furthermore, there are concerns that tranexamic acid may have prothrombotic and proconvulsant effects. Methods In a trial with a 2‐by‐2 factorial design, we randomly assigned patients who were scheduled to undergo coronary‐artery surgery and were at risk for perioperative complications to receive aspirin or placebo and tranexamic acid or placebo. The results of the tranexamic acid comparison are reported here. The primary outcome was a composite of death and thrombotic complications (nonfatal myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) within 30 days after surgery. Results Of the 4662 patients who were enrolled and provided consent, 4631 underwent surgery and had available outcomes data; 2311 were assigned to the tranexamic acid group and 2320 to the placebo group. A primary outcome event occurred in 386 patients (16.7%) in the tranexamic acid group and in 420 patients (18.1%) in the placebo group (relative risk, 0.92; 95% confidence interval, 0.81 to 1.05; P=0.22). The total number of units of blood products that were transfused during hospitalization was 4331 in the tranexamic acid group and 7994 in the placebo group (P<0.001). Major hemorrhage or cardiac tamponade leading to reoperation occurred in 1.4% of the patients in the tranexamic acid group and in 2.8% of the patients in the placebo group (P=0.001), and seizures occurred in 0.7% and 0.1%, respectively (P=0.002 by Fishers exact test). Conclusions Among patients undergoing coronary‐artery surgery, tranexamic acid was associated with a lower risk of bleeding than was placebo, without a higher risk of death or thrombotic complications within 30 days after surgery. Tranexamic acid was associated with a higher risk of postoperative seizures. (Funded by the Australian National Health and Medical Research Council and others; ATACAS Australia New Zealand Clinical Trials Registry number, ACTRN12605000557639.)

Measurement of disability-free survival after surgery.

Background:Survival and freedom from disability are arguably the most important patient-centered outcomes after surgery, but it is unclear how postoperative disability should be measured. The authors thus evaluated the World Health Organization Disability Assessment Schedule 2.0 in a surgical population. Methods:The authors examined the psychometric properties of World Health Organization Disability Assessment Schedule 2.0 in a diverse cohort of 510 surgical patients. The authors assessed clinical acceptability, validity, reliability, and responsiveness up to 12 months after surgery. Results:Criterion and convergent validity of World Health Organization Disability Assessment Schedule 2.0 were supported by good correlation with the 40-item quality of recovery scale at 30 days after surgery (r = −0.70) and at 3, 6, and 12 months after surgery with physical functioning (The Katz index of independence in Activities of Daily Living; r = −0.70, r = −0.60, and rho = −0.47); quality of life (EQ-5D; r = −0.57, −0.60, and −0.52); and pain interference scores (modified Brief Pain Inventory Short Form; r = 0.72, 0.74, and 0.81) (all P < 0.0005). Construct validity was supported by increased hospital stay (6.9 vs. 5.3 days, P = 0.008) and increased day 30 complications (20% vs. 11%, P = 0.042) in patients with new disability. There was excellent internal consistency with Cronbach’s &agr; and split-half coefficients greater than 0.90 at all time points (all P < 0.0005). Responsiveness was excellent with effect sizes of 3.4, 3.0, and 1.0 at 3, 6, and 12 months after surgery, respectively. Conclusions:World Health Organization Disability Assessment Schedule 2.0 is a clinically acceptable, valid, reliable, and responsive instrument for measuring postoperative disability in a diverse surgical population. Its use as an endpoint in future perioperative studies can provide outcome data that are meaningful to clinicians and patients alike.

An enhanced recovery after surgery program for hip and knee arthroplasty

Objective: To institute and evaluate the benefits of an enhanced recovery after surgery (ERAS) program across three hospitals in Victoria.

Restrictive versus Liberal Fluid Therapy for Major Abdominal Surgery

BACKGROUND Guidelines to promote the early recovery of patients undergoing major surgery recommend a restrictive intravenous‐fluid strategy for abdominal surgery. However, the supporting evidence is limited, and there is concern about impaired organ perfusion. METHODS In a pragmatic, international trial, we randomly assigned 3000 patients who had an increased risk of complications while undergoing major abdominal surgery to receive a restrictive or liberal intravenous‐fluid regimen during and up to 24 hours after surgery. The primary outcome was disability‐free survival at 1 year. Key secondary outcomes were acute kidney injury at 30 days, renal‐replacement therapy at 90 days, and a composite of septic complications, surgical‐site infection, or death. RESULTS During and up to 24 hours after surgery, 1490 patients in the restrictive fluid group had a median intravenous‐fluid intake of 3.7 liters (interquartile range, 2.9 to 4.9), as compared with 6.1 liters (interquartile range, 5.0 to 7.4) in 1493 patients in the liberal fluid group (P<0.001). The rate of disability‐free survival at 1 year was 81.9% in the restrictive fluid group and 82.3% in the liberal fluid group (hazard ratio for death or disability, 1.05; 95% confidence interval, 0.88 to 1.24; P=0.61). The rate of acute kidney injury was 8.6% in the restrictive fluid group and 5.0% in the liberal fluid group (P<0.001). The rate of septic complications or death was 21.8% in the restrictive fluid group and 19.8% in the liberal fluid group (P=0.19); rates of surgical‐site infection (16.5% vs. 13.6%, P=0.02) and renal‐replacement therapy (0.9% vs. 0.3%, P=0.048) were higher in the restrictive fluid group, but the between‐group difference was not significant after adjustment for multiple testing. CONCLUSIONS Among patients at increased risk for complications during major abdominal surgery, a restrictive fluid regimen was not associated with a higher rate of disability‐free survival than a liberal fluid regimen and was associated with a higher rate of acute kidney injury. (Funded by the Australian National Health and Medical Research Council and others; RELIEF ClinicalTrials.gov number, NCT01424150.)

Nitrous oxide and serious long-term morbidity and mortality in the evaluation of nitrous oxide in the gas mixture for anaesthesia (ENIGMA)-II trial

Background:The Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II trial randomly assigned 7,112 noncardiac surgery patients at risk of perioperative cardiovascular events to 70% N2O or 70% N2 groups. The aim of this follow-up study was to determine the effect of nitrous oxide on a composite primary outcome of death and major cardiovascular events at 1 yr after surgery. Methods:One-year follow-up was conducted via a medical record review and telephone interview. Disability was defined as a Katz index of independence in activities of daily living score less than 8. Adjusted odds ratios and hazard ratios were calculated as appropriate for primary and secondary outcomes. Results:Among 5,844 patients evaluated at 1 yr, 435 (7.4%) had died, 206 (3.5%) had disability, 514 (8.8%) had a fatal or nonfatal myocardial infarction, and 111 (1.9%) had a fatal or nonfatal stroke during the 1-yr follow-up period. Exposure to nitrous oxide did not increase the risk of the primary outcome (odds ratio, 1.08; 95% CI, 0.94 to 1.25; P = 0.27), disability or death (odds ratio, 1.07; 95% CI, 0.90 to 1.27; P = 0.44), death (hazard ratio, 1.17; 95% CI, 0.97 to 1.43; P = 0.10), myocardial infarction (odds ratio, 0.97; 95% CI, 0.81 to 1.17; P = 0.78), or stroke (odds ratio, 1.08; 95% CI, 0.74 to 1.58; P = 0.70). Conclusion:These results support the long-term safety of nitrous oxide administration in noncardiac surgical patients with known or suspected cardiovascular disease.

Restrictive versus liberal fluid therapy in major abdominal surgery (RELIEF): Rationale and design for a multicentre randomised trial

Introduction The optimal intravenous fluid regimen for patients undergoing major abdominal surgery is unclear. However, results from many small studies suggest a restrictive regimen may lead to better outcomes. A large, definitive clinical trial evaluating perioperative fluid replacement in major abdominal surgery, therefore, is required. Methods/analysis We designed a pragmatic, multicentre, randomised, controlled trial (the RELIEF trial). A total of 3000 patients were enrolled in this study and randomly allocated to a restrictive or liberal fluid regimen in a 1:1 ratio, stratified by centre and planned critical care admission. The expected fluid volumes in the first 24 hour from the start of surgery in restrictive and liberal groups were ≤3.0 L and ≥5.4 L, respectively. Patient enrolment is complete, and follow-up for the primary end point is ongoing. The primary outcome is disability-free survival at 1 year after surgery, with disability defined as a persistent (at least 6 months) reduction in functional status using the 12-item version of the World Health Organisation Disability Assessment Schedule. Ethics/dissemination The RELIEF trial has been approved by the responsible ethics committees of all participating sites. Participant recruitment began in March 2013 and was completed in August 2016, and 1-year follow-up will conclude in August 2017. Publication of the results of the RELIEF trial is anticipated in early 2018. Trial registration number ClinicalTrials.gov identifier NCT01424150.

Automated preoperative assessment of endothelial dysfunction and risk stratification for perioperative myocardial injury in patients undergoing non-cardiac surgery

BACKGROUND Myocardial injury after non-cardiac surgery (MINS) is a common complication with associated serious morbidity and mortality. Endothelial dysfunction might play an important role in MINS, and its rapid assessment could provide a novel method of risk stratification before surgery. METHODS We studied 238 subjects scheduled to undergo intermediate or high-risk surgery in a two-centre prospective study to determine whether preoperative endothelial dysfunction identified by a reactive hyperaemia-peripheral arterial tonometry (RH-PAT) index could provide effective risk stratification for MINS, defined as serum troponin ≥0.04 μg litre(-1), within 3 postoperative days. RESULTS The primary outcome occurred in 35 subjects (14.7%). Endothelial dysfunction was defined as an RH-PAT index of ≤1.22. Adjusted for age, Lee index and a composite measure of the extent of surgery, endothelial dysfunction was associated with MINS [odds ratio 10.1, 95% confidence interval (CI) 3.3-30.9, P=0.001] and increased time to discharge from hospital after surgery (hazard ratio 0.39, 95% CI 0.23-0.65, P=0.001). Endothelial dysfunction identified MINS with a sensitivity of 31%, a specificity of 96%, and a positive diagnostic likelihood ratio of 8.0. Risk classification for MINS was improved by the addition of RH-PAT-defined endothelial dysfunction to the Lee index (c-statistic increased from 0.69 to 0.77; integrated discrimination improvement 0.11, P=0.003). However, prognostic utility varied widely between sites. CONCLUSIONS For patients undergoing non-cardiac surgery, non-invasive assessment of endothelial function might enhance preoperative risk stratification for perioperative myocardial injury. However, unexplained large inter-site variation in prognostic utility could limit widespread application and needs to be further understood.

Brain Natriuretic Peptide (BNP) as a Biomarker of Myocardial Ischemia-Reperfusion Injury in Cardiac Transplantation

OBJECTIVES To evaluate brain natriuretic peptide (BNP) as a biomarker of ischemia-reperfusion injury in cardiac transplantation DESIGN A prospective cohort study. SETTING A single academic medical center. PARTICIPANTS Adult patients undergoing orthotopic cardiac transplantation (n = 25). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS The authors performed serial measurements of BNP and troponin-I in cardiac allograft donors and recipients, determining the relationship between these biomarkers and established risk factors for and measures of early graft dysfunction. Postoperative BNP correlated moderately with allograft ischemic time (ρ = 0.52, p = 0.01), donor BNP (ρ = 0.45, p = 0.03), and donor troponin-I (ρ = 0.49, p = 0.01). Postoperative BNP was higher in patients with persistently elevated inotrope requirements and enabled the early identification of such patients. In contrast, there was no association between postoperative troponin-I and these same parameters. CONCLUSIONS Postoperative BNP is associated with preimplantation and clinical performance parameters related to allograft ischemia-reperfusion injury at the time of cardiac transplantation, providing preliminary evidence to support its potential use as an ischemia-reperfusion injury biomarker in this context.

Validation of days at home as an outcome measure after surgery: a prospective cohort study in Australia

Objective To evaluate ‘days at home up to 30 days after surgery’ (DAH30) as a patient-centred outcome measure. Design Prospective cohort study. Data source Using clinical trial data (seven trials, 2109 patients) we calculated DAH30 from length of stay, readmission, discharge destination and death up to 30 days after surgery. Main outcome The association between DAH30 and serious complications after surgery. Results One or more complications occurred in 263 of 1846 (14.2%) patients, including 19 (1.0%) deaths within 30 days of surgery; 245 (11.6%) patients were discharged to a rehabilitation facility and 150 (7.1%) were readmitted to hospital within 30 days of surgery. The median DAH30 was significantly less in older patients (p<0.001), those with poorer physical functioning (p<0.001) and in those undergoing longer operations (p<0.001). Patients with serious complications had less days at home than patients without serious complications (20.5 (95% CI 19.1 to 21.9) vs 23.9 (95% CI 23.8 to 23.9) p<0.001), and had higher rates of readmission (16.0% vs 5.9%; p<0.001). After adjusting for patient age, sex, physical status and duration of surgery, the occurrence of postoperative complications was associated with fewer days at home after surgery (difference 3.0(95% CI 2.1 to 4.0) days; p<0.001). Conclusions DAH30 has construct validity and is a readily obtainable generic patient-centred outcome measure. It is a pragmatic outcome measure for perioperative clinical trials.