Editor's Choice - Prevalence of Smoking and Impact on Peri-Operative Outcomes After Elective Abdominal Aortic Aneurysm Repair.

OBJECTIVE: The contemporary burden of smoking in patients undergoing elective abdominal aortic aneurysm (AAA) repair in the UK is unknown. This study aimed to quantify the prevalence of smoking in patients undergoing AAA repair in the UK and determine the association between smoking and peri-operative outcomes. METHODS: This was an observational cohort study. The National Vascular Registry was interrogated for adults undergoing elective infrarenal AAA repair from 2014 to 2021 for prevalence of current smokers, former smokers, and non-smokers over time. The primary outcomes were post-operative complications by smoking status. Secondary outcomes were variation in smoking rates over time and by hospital, in hospital mortality, and length of stay by smoking status. All analyses were adjusted using the validated British Aneurysm Repair score. RESULTS: Overall, 26 916 patients undergoing elective AAA repair were included (21.9% smokers, 62.2% former smokers, 15.9% non-smokers). The prevalence of smoking did not change over time, with a 2.4 fold variation between UK hospitals (range 13.0 - 31.8% excluding outliers). In hospital mortality was not significantly different between smokers, former smokers, and non-smokers (p > .050 for all comparisons). Compared with non-smokers, smoking was associated with increased overall (odds ratio [OR] 1.40, 95% confidence interval [CI] 1.24 - 1.57) and respiratory complications (OR 1.98, 95% CI 1.63 - 2.39), limb ischaemia (OR 1.63, 95% CI 1.19 - 2.23), bowel ischaemia (OR 1.64, 95% CI 1.06 - 2.54), return to theatre (OR 1.38, 95% CI 1.11 - 1.71), and intensive care admission (OR 1.43, 95% CI 1.31 - 1.56). Compared with former smokers, smoking was associated with increased overall (OR 1.24, 95% CI 1.14 - 1.36), respiratory (OR 1.44, 95% CI 1.27 - 1.63) and limb ischaemia complications (OR 1.48, 95% CI 1.19 - 1.84), and intensive care admission (OR 1.37, 95% CI 1.28 - 1.46). On analysis of the endovascular aneurysm repair subgroup, active smoking was associated with significantly higher rates of limb ischaemia compared with former and non-smokers (OR 2.12, 95% CI 1.49 - 3.01 and OR 1.94, 95% CI 1.19 - 3.16 respectively). CONCLUSION: The prevalence of smoking remains high in patients undergoing elective AAA repair with no evidence of a decline in active smokers from 2014 to 2021 compared with the general UK population. Smoking is associated with increased peri-operative complication rates.

Exploring the Reporting Standards of Randomised Controlled Trials Involving Endovascular Interventions for Peripheral Arterial Disease: A Systematic Review.

OBJECTIVE: Endovascular technology innovation requires rigorous evaluation in high quality randomised controlled trials (RCTs). However, due to numerous methodological challenges, RCTs evaluating endovascular interventions are complex and potentially difficult to design, conduct, and report. This systematic review aimed to assess the quality of reporting of RCTs for endovascular interventions for lower limb peripheral arterial disease (PAD). DATA SOURCES AND REVIEW METHODS: A systematic review of Medline, Embase, and the Cochrane Library databases from inception to December 2021 was performed to identify RCTs including participants with PAD undergoing any infrainguinal lower limb endovascular intervention. Study data were extracted and assessed against the Consolidating Standards of Reporting Trials extension for Non-Pharmacological Treatments (CONSORT-NPT) and the Template for Intervention Description and Replication (TIDieR) checklists. Descriptive statistics were used to summarise general study details and reporting standards of the trials. RESULTS: After screening 6 567 abstracts and 526 full text articles, 112 eligible studies were identified, reporting on 228 different endovascular devices and techniques. Details judged sufficient to replicate the investigated intervention were provided for 47 (21%) interventions. It was unclear whether the description was reported with sufficient details in a further 56 (24%), and the description was judged inadequate in 125 (55%). Any intervention descriptions were provided for 184 (81%), with variable levels of detail (some in 134 [59%] and precise in 50 [22%]). Standardisation of intervention or some aspect of this was reported in 25 (22%) trials, but only one specified that adherence to the study protocol would be monitored. CONCLUSION: The quality of the reporting standards of RCTs investigating lower limb endovascular treatments is severely limited because the interventions are poorly described, standardised, and reported. PROSPERO registration number: CRD42022288214.

Consensus statement on the interhospital transfer of patients with acute aortic syndrome: TRAVERSING Delphi study.

BACKGROUND: Standardisation of referral pathways and the transfer of patients with acute aortic syndromes (AAS) to regional centres are recommended by NHS England in the Acute Aortic Dissection Toolkit. The aim of the Transfer of Thoracic Aortic Vascular Emergencies to Regional Specialist INstitutes Group study was to establish an interdisciplinary consensus on the interhospital transfer of patients with AAS to specialist high-volume aortic centres. METHODS: Consensus on the key aspects of interhospital transfer of patients with AAS was established using the Delphi method, in line with Conducting and Reporting of Delphi Studies guidelines. A national patient charity for aortic dissection was involved in the design of the Delphi study. Vascular and cardiothoracic surgeons, emergency physicians, interventional radiologists, cardiologists, intensivists and anaesthetists in the United Kingdom were invited to participate via their respective professional societies. RESULTS: Three consecutive rounds of an electronic Delphi survey were completed by 212, 101 and 58 respondents, respectively. Using predefined consensus criteria, 60 out of 117 (51%) statements from the survey were included in the consensus statement. The study concluded that patients can be taken directly to a specialist aortic centre if they have typical symptoms of AAS on the background of known aortic disease or previous aortic intervention. Accepted patients should be transferred in a category 2 ambulance (response time <18 min), ideally accompanied by transfer-trained personnel or Adult Critical Care Transfer Services. A clear plan should be agreed in case of a cardiac arrest occurring during the transfer. Patients should reach the aortic centre within 4 hours of the initial referral from their local hospital. CONCLUSIONS: This consensus statement is the first set of national interdisciplinary recommendations on the interhospital transfer of patients with AAS. Its implementation is likely to contribute to safer and more standardised emergency referral pathways to regional high-volume specialist aortic units.

Protocol for a systematic review and meta-analysis of tobacco-cessation interventions delivered perioperatively.

INTRODUCTION: Tobacco smoking is associated with a substantially increased risk of perioperative complications. The perioperative period is an opportunity to introduce tobacco-cessation strategies. A previous systematic review provided evidence that perioperative interventions increase short-term abstinence and may reduce postoperative complications. The evidence base has since expanded, with the subsequent publication of numerous randomised studies. This protocol outlines a systematic review examining the impact of perioperative tobacco-cessation interventions on successful abstinence from tobacco smoking, and on the incidence of perioperative complications. METHODS AND ANALYSIS: A systematic search of the literature will be run across EMBASE (Ovid), MEDLINE (Ovid), CINAHL (Ebsco) and PsycInfo (ProQuest), from inception to present, using text words and subject headings. Randomised controlled trials published in English, examining adults in the perioperative period and reporting the outcomes from tobacco-cessation interventions will be included.Abstract screening and data extraction will be performed by five reviewers. Each abstract will be screened by two blinded reviewers, with discrepancies resolved by group consensus. The primary outcome will be point prevalence abstinence from tobacco-use at the time of surgery. Secondary outcomes are prolonged abstinence from tobacco use at 6 months and 12 months, and postoperative complications. Any other reported outcomes will be documented in the descriptive analysis. The review will also describe details of the investigated perioperative tobacco-cessation interventions. If sufficient studies report relevant data, meta-analysis of the primary and secondary outcomes will be undertaken. Results will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement. ETHICS AND DISSEMINATION: No ethical approval is required. Results will be disseminated by open-access, peer-reviewed journal publication and conference presentations. Results will underpin future work to modify perioperative tobacco-cessation interventions to enhance engagement and accessibility, and to develop trials aiming to facilitate abstinence from tobacco-use in patients presenting for surgery.

Does melatonin administration reduce the incidence of postoperative delirium in adults? Systematic review and meta-analysis.

Postoperative delirium (POD) is common. It is associated with increased morbidity and mortality. Many cases may be preventable and melatonin offers promise as a preventative agent. OBJECTIVE: This systematic review provides an up-to-date synthesis of the evidence on the effect of melatonin in preventing POD. DESIGN: A systematic search of randomised controlled trials of melatonin in POD was run across multiple databases (EMBASE, MEDLINE, CINAHL, PsycINFO) and a clinical trials registry (ClinicalTrials.org) (1 January 1990 to 5 April 2022). Studies examining the effects of melatonin on POD incidence in adults are included. Risk of bias was assessed using the Cochrane risk of bias 2 tool. OUTCOME MEASURES: The primary outcome is POD incidence. Secondary outcomes are POD duration and length of hospital stay. Data synthesis was undertaken using a random-effects meta-analysis and presented using forest plots. A summary of methodology and outcome measures in included studies is also presented. RESULTS: Eleven studies, with 1244 patients from a range of surgical specialties were included. Seven studies used melatonin, in variable doses, and four used ramelteon. Eight different diagnostic tools were used to diagnose POD. Time points for assessment also varied. Six studies were assessed as low risk of bias and five as some concern. The combined OR of developing POD in the melatonin groups versus control was 0.41 (95% CI 0.21 to 0.80, p=0.01). CONCLUSION: This review found that melatonin may reduce the incidence of POD in adults undergoing surgery. However, included studies displayed inconsistency in their methodology and outcome reporting. Further work to determine the optimum regime for melatonin administration, along with consensus of how best to evaluate results, would be beneficial. PROSPERO REGISTRATION NUMBER: CRD42021285019.

Protocol for a systematic review of reporting standards of lower limb endovascular interventions in peripheral arterial disease.

INTRODUCTION: Techniques and devices for the endovascular treatment of peripheral arterial disease (PAD) are continuously evolving. High-quality clinical trials limit the variation in how endovascular interventions are described, performed and reported. The aim of this systematic review is to assess the quality of reporting standards in randomised controlled trials (RCTs) of endovascular lower limb interventions against the Consolidated Standards of Reporting Trials for Non-Pharmacologic Treatments (CONSORT-NPT) and template for intervention description and replication (TIDieR) framework. METHODS: Randomised trials including participants with peripheral arterial disease undergoing any infra-inguinal lower limb endovascular arterial intervention, searched from Medline, Embase and Cochrane Library databases from inception to December 2021, will be included. All study data, including details of the procedure investigated, will be extracted in keeping with the CONSORT-NPT and TIDieR checklist. Descriptive statistics will be used to summarise general study details and reporting standards of the trials. DISCUSSION: The results will be used to inform the design of future RCTs in this area by optimising the way the interventions are described, standardised, and monitored. The systematic review will be disseminated via peer-reviewed manuscripts and presentations at relevant conferences. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022288214.

Comprehensive geriatric assessment (CGA) in perioperative care: a systematic review of a complex intervention.

OBJECTIVES: Comprehensive geriatric assessment (CGA) is a complex intervention applied to older people with evidence of benefit in medical populations. The aim of this systematic review was to describe how CGA is applied to surgical populations in randomised controlled trials. This will provide a basis for design of future studies focused on optimising CGA as a complex intervention. SETTING: A systematic review of randomised controlled trials. PARTICIPANTS: A systematic search was performed for studies of CGA in the perioperative period across Ovid MEDLINE, Ovid EMBASE, CINAHL and Cochrane CENTRAL, from inception to March 2021. INTERVENTIONS: Any randomised controlled trials of perioperative CGA versus 'standard care' were included. OUTCOME MEASURES: Qualitative description of CGA. RESULTS: 12 121 titles and abstracts were screened, 68 full-text articles were assessed for eligibility and 22 articles included, reporting on 13 trials. 10 trials focused on inpatients with hip fracture, with 7 of these delivering CGA on a geriatric medicine ward, 3 on a surgical ward. The remaining three trials were in elective general surgery all delivering CGA on a surgical ward. CGA components, duration of intervention and personnel delivering the intervention were highly variable across the different studies. Trials favoured postoperative delivery of CGA (11/13). Only four trials reported data on adherence to the CGA intervention. CONCLUSIONS: CGA as an intervention is variably described and delivered in randomised controlled trials in the perioperative setting. The reporting of both the intervention and standard care is often poor with little focus on adherence. Future research should focus on clearly defining and standardising the intervention as well as measuring adherence within trials. PROSPERO REGISTRATION NUMBER: CRD42020221797.

Melatonin for the prevention of postoperative delirium in older adults: a protocol for a systematic review and meta-analysis.

INTRODUCTION: Postoperative delirium (POD) is a major cause of morbidity, particularly in elderly patients. Melatonin has been suggested as a low-risk pharmacological intervention to help prevent POD. A previous systematic review found limited high-quality evidence to support the use of melatonin in the prevention of POD. Several further randomised studies have since been published. This systematic review aims to synthesise the evidence from randomised controlled trials (RCTs) examining the effect of melatonin on the prevention of POD in older adults. METHODS AND ANALYSIS: A systematic search of RCTs of melatonin (any dose and formulation) in POD will be run across Embase, Medline, CINAHL and PsychInfo. RCTs published from January 1990 until the end of February 2022 and reporting outcomes for melatonin use to prevent POD in patients will be included. Screening of search results and data extraction from included articles will be performed by two independent reviewers. The primary outcome will be incidence of POD in older adults undergoing surgery. Secondary outcomes are delirium duration and length of hospital stay. The review will also describe the dosage, timing and administration regimes of melatonin therapy and as well as the scales and definitions used to describe POD. A registry review of ongoing trials will be also be performed. For the meta-analysis, data will be pooled using a random effects model to generate a forest plot and obtain an odds ratio (OR) for the incidence of POD. Results will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. ETHICS AND DISSEMINATION: No ethical approval is required. This review will be disseminated via peer-reviewed manuscript and conferences. The results will be used as the basis of work to optimise this intervention for future trials in surgical populations. PROSPERO REGISTRATION NUMBER: This review is registered with PROSPERO (CRD42021285019).

The Effect of Mode of Anaesthesia on Outcomes After Elective Endovascular Repair of Abdominal Aortic Aneurysm.

OBJECTIVE: Endovascular aneurysm repair (EVAR) is the most commonly used method to repair abdominal aortic aneurysms. EVAR can be performed using a variety of anaesthetic techniques, including general anaesthetic (GA), regional anaesthetic (RA), and local anaesthetic (LA), but little is known about the effects that each of these anaesthetic modes have on patient outcome. The aim of this study was to assess the effect of anaesthetic technique on early outcomes after elective EVAR. METHODS: Data from the UK's National Vascular Registry were analysed. All patients undergoing elective standard infrarenal EVAR between 1 January 2014 and 31 December 2016 were included. Patients with a symptomatic aneurysm treated semi-electively were excluded. The primary outcome was in hospital death within 30 days of surgery. Secondary outcomes included post-operative complications and length of hospital stay. Time to event outcomes were compared using Cox proportional hazards regression adjusted for confounders, including British Aneurysm Repair score (a validated aneurysm risk prediction score that is calculated using age, sex, creatinine, cardiac disease, electrocardiogram, previous aortic surgery, white blood cell count, serum sodium, abdominal aortic aneurysm diameter, and American Society of Anaesthesiologists grade) and chronic lung disease. RESULTS: A total of 9783 patients received an elective, standard infrarenal EVAR (GA, n = 7069; RA, n = 2347; and LA, n = 367) across 89 hospitals. RA and/or LA was used in 82 hospitals. There were 64 in hospital deaths within 30 days, 50 (0.9% mortality at 30 days, 95% confidence interval [CI] 0.7-1.2) in the GA group, 11 (0.6%, 95% CI 0.3-1.1) in the RA group, and three (1.5%, 95% CI 0.5-4.7) in the LA group. The mortality rate differed between groups (p = .03) and was significantly lower in the RA group compared with the GA group (adjusted hazard ratio [aHR] RA/GA 0.37 [95% CI 0.17-0.81]; LA/GA 0.63 [95% CI 0.15-2.69]). The median length of stay was two days for all modes of anaesthesia, but patients were discharged from hospital more quickly in the RA and LA groups than the GA group (aHR RA/GA 1.10 [95% CI 1.03-1.17]; LA/GA 1.15 [95% CI 1.02-1.29]). Overall, 20.7% of patients experienced one or more complications (GA group, 22.1%; RA group, 16.8%; LA group, 17.7%) and pulmonary complications occurred with similar frequency in the three groups (overall 2.4%, adjusted odds ratio RA/GA 0.93 [95% CI 0.66-1.32]; LA/GA 0.82 [95% CI 0.41-1.63]). CONCLUSION: Thirty day mortality was lower with RA than with GA, but mode of anaesthesia was not associated with increased complications for patients undergoing elective standard infrarenal EVAR.

Protocol for a systematic review of reporting standards of anaesthetic interventions in randomised controlled trials.

INTRODUCTION: There is significant variation in how anaesthesia is defined and reported in clinical research. This lack of standardisation complicates the interpretation of published evidence and planning of future clinical trials. This systematic review will assess the reporting of anaesthesia as an intervention in randomised controlled trials (RCT) against the Consolidated Standards of Reporting Trials for Non-Pharmacological Treatments (CONSORT-NPT) framework. METHODS AND ANALYSIS: Online archives of the top six journals ranked by impact factor for anaesthesia and the top three general medicine and general surgery journals will be systematically hand searched over a 42-month time period to identify RCTs describing the use of anaesthetic interventions for any invasive procedure. All modes of anaesthesia and anaesthesia techniques will be included. All study data, including the type of anaesthetic intervention described, will be extracted in keeping with the CONSORT-NPT checklist. Descriptive statistics will be used to summarise general study details including types/modes of anaesthetic interventions, and reporting standards of the trials. ETHICS AND DISSEMINATION: No ethical approval is required. The results will be used to inform a funding application to formally standardise general, local, regional anaesthesia and sedation for use in clinical research. The systematic review will be disseminated via peer-reviewed manuscript and conferences. PROSPERO REGISTRATION NUMBER: CRD42019141670.

Choice of anaesthetic in emergency operations: a protocol for a scoping review.

INTRODUCTION: The effect of mode of anaesthesia in emergency surgery is uncertain. This scoping review will identify and summarise the evidence for local, regional or general anaesthetic in adult patients undergoing emergency surgical procedures. METHODS AND ANALYSIS: Scoping review methodology will be followed. The search will be run in EMBASE and Medline. Further articles will be identified from searching references in relevant studies. A descriptive analysis will be performed considering the following main outcomes; mortality, length of stay, intensive care unit (ICU) admission, postoperative pain and morbidity. Data on complications including acute coronary syndrome, stroke, thromboembolic events, delirium, acute kidney injury, respiratory tract infection, surgical site infection and study-specific additional outcomes will also be collected. ETHICS AND DISSEMINATION: No ethics approval is required. The results will be used to inform a funding application for a clinical trial comparing local/regional anaesthetic with general anaesthetic. The study will be disseminated via peer-reviewed manuscript and conferences. TRIAL REGISTRATION NUMBER: Results will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Statement. There are currently no registries that accept scoping reviews.

Effects of Ischemic Preconditioning on Abdominal Aortic Aneurysm Repair: A Systematic Review and Meta-analysis.

BACKGROUND: Ischemic preconditioning is an innate mechanism of cytoprotection against ischemia, with potential for end-organ protection. The primary goal of this study was to systematically review the literature to determine the effect of ischemic preconditioning on outcomes after open and endovascular abdominal aortic aneurysm (AAA) repair. METHODS: The methodology followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. We included randomized clinical trials that evaluated the effect of remote ischemic preconditioning (RIPC) in reducing morbidity and mortality in patients undergoing open or endovascular AAA repair surgery. The primary outcomes were death, myocardial infarction, and renal impairment. Outcomes were addressed separately for open AAA repair and endovascular AAA repair (EVAR). Data were collected on patient characteristics, methodology, and preconditioning protocol for each trial. RESULTS: Nine trials of ischemic preconditioning in aortic aneurysm surgery were included with a total of 599 patients; 336 patients were included in the open AAA repair meta-analysis, and 263 patients were included in the EVAR meta-analysis. For both open and endovascular repairs, ischemic preconditioning did not have a significant effect on death, myocardial infarction, or renal impairment requiring dialysis. CONCLUSIONS: The randomized clinical trials investigating the effect of ischemic preconditioning on outcomes after open and endovascular AAA repair that have been completed to date have not been adequately powered to evaluate improvements in patient-important outcomes. The evidence is insufficient to support the use of ischemic preconditioning for AAA repair in clinical practice. The variability in treatment effect across studies may be explained by clinical and methodological heterogeneity.

Type of Anesthesia for Endovascular Abdominal Aortic Aneurysm Repair.

OBJECTIVE: Endovascular aneurysm repair (EVAR) is used increasingly in the management of patients with abdominal aortic aneurysms (AAAs), including in the emergency setting for ruptured AAA. The lower mortality among patients undergoing emergency EVAR under local anesthesia (LA) observed in the Immediate Management of Patients with Rupture: Open Versus Endovascular Repair trial has sparked renewed interest in the anesthesia choice for EVAR. This systematic review evaluates the effect of mode of anesthesia on outcomes after EVAR. DESIGN: The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The primary outcome was in-hospital/30-day mortality, and both emergency and elective EVAR were included. The relative risk of death was estimated for each individual study without adjustment for potential confounding factors. SETTING: Hospitals. PARTICIPANTS: A total of 39,744 patients from 22 nonrandomized studies were included in the analysis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Sixteen studies in 23,202 patients compared LA to general anesthesia (GA) and reported in-hospital/30-day mortality. The unadjusted risk of death after emergency EVAR with LA was lower than with GA. Trends in elective surgery were less clear. CONCLUSION: There is some evidence across both emergency and elective settings to suggest that mode of anesthesia may be associated with improved outcomes. In particular, LA appears to have a positive effect on outcome after emergency EVAR. Because of the lack of randomized trial data, a significant risk of confounding remains. The optimal mode of anesthesia for EVAR should be investigated further and the reasons why particular anesthesia techniques are chosen for particular patients identified.

30-day mortality after haemodialysis vascular access surgery: a retrospective observational study.

PURPOSE: The prevalence of haemodialysis is increasing globally. There is a consensus of international opinion that permanent vascular access is preferred for haemodialysis. Patients with end-stage renal disease carry a high burden of cardiovascular comorbidity. There is a lack of data to quantify the post-operative risk of vascular access surgery. This study looked to establish the 30-day post-operative mortality for patients undergoing surgery to create vascular access and to measure for differences between the types of access created and the mode of anaesthesia. METHODS: We conducted a retrospective study of all cases over a 5-year period at a tertiary renal unit in the UK. Data recorded included co-morbidity, time on renal replacement therapy, type of access created, mode of anaesthesia and 30-day mortality. The incident risk was calculated and logistic regression used to calculate the adjusted odds ratio. RESULTS: A total of 1404 operations were included. 30-day mortality for the whole cohort was 1.1% (16/1404). The adjusted odds ratio of death at 30 days using an upper limb fistula as a reference was 5.27 for an upper limb graft (p = 0.005) and 11.51 (p = 0.007) for any lower limb access. Using local anaesthesia as a reference the adjusted odds ratio for surgery under general anaesthesia was 6.28 (p = 0.001). CONCLUSIONS: Vascular surgery for haemodialysis is associated with significant and variable post-operative mortality; this study highlights the need for careful pre-operative planning in this complex group of patients.

Remote ischaemic preconditioning versus sham procedure for abdominal aortic aneurysm repair: an external feasibility randomized controlled trial.

BACKGROUND: Despite advances in perioperative care, elective abdominal aorta aneurysm (AAA) repair carries significant morbidity and mortality. Remote ischaemic preconditioning (RIC) is a physiological phenomenon whereby a brief episode of ischaemia-reperfusion protects against a subsequent longer ischaemic insult. Trials in cardiovascular surgery have shown that RIC can protect patients' organs during surgery. The aim of this study was to investigate whether RIC could be successfully introduced in elective AAA repair and to obtain the information needed to design a multi-centre RCT. METHODS: Consecutive patients presenting for elective AAA repair, using an endovascular (EVAR) or open procedure, in a single large city hospital in the UK were assessed for trial eligibility. Patients who consented to participate were randomized to receive RIC (three cycles of 5 min ischaemia followed by 5 min reperfusion in the upper arm immediately before surgery) or a sham procedure. Patients were followed up for 6 months. We assessed eligibility and consent rates, the logistics of RIC implementation, randomization, blinding, data capture, patient and staff opinion, and variability and frequency of clinical outcome measures. RESULTS: Between January 2010 and December 2012, 98 patients were referred for AAA repair, 93 were screened, 85 (91%) were eligible, 70 were approached for participation and 69 consented to participate; 34 were randomized to RIC and 35 to the sham procedure. There was a greater than expected variation in the complexity of EVAR that impacted the outcomes. Acute kidney injury occurred in 28 (AKIN 1: 23%; AKIN 2: 15% and AKIN 3: 3%) and 7 (10%) had a perioperative myocardial infarction. Blinding was successful, and interviews with participants and staff indicated that the procedure was acceptable. There were no adverse events secondary to the intervention in the 6 months following the intervention. CONCLUSIONS: This study provided essential information for the planning and design of a multi-centre RCT to assess effectiveness of RIC for improving clinical outcomes in elective AAA repair. Patient consent was high, and the RIC intervention was carried out with minimal disruption to clinical care. The allocation scheme for a definite trial should take into account both the surgical procedure and its complexity to avoid confounding the effect of the RIC, as was observed in this study. TRIAL REGISTRATION: Current Controlled Trials ISRCTN19332276 (date of registration: 16 March 2012). The trial protocol is available from the corresponding author.

Is there a role for remote ischaemic postconditioning in cardiopulmonary resuscitation?

Cardiac arrest causes whole body ischaemic injury and cellular death. Successful cardiopulmonary resuscitation (CPR) can subsequently lead to a global reperfusion phenomenon with a paradoxically increased rate of cellular death. Interventions that decrease the ischaemia-reperfusion injury may be useful in the treatment of these patients. Remote ischaemic postconditioning with transient limb ischaemia is feasible in cardiac arrest patients. This article discusses the concept of ischaemic pre- and postconditioning and its potential use in patients during CPR and after return of a spontaneous circulation.

Effect of aprotinin on renal dysfunction in patients undergoing on-pump and off-pump cardiac surgery: a retrospective observational study.

BACKGROUND: Aprotinin is used during cardiac surgery for its blood-saving effects. However, reports suggest a possible association between use of this drug and increased renal dysfunction and mortality. We investigated the effect of aprotinin on renal dysfunction in cardiac surgery, considering the cofactors on-pump versus off-pump surgery and co-medication with angiotensin-converting enzyme (ACE) inhibitors. METHODS: Our analysis included 9875 patients undergoing on-pump or off-pump cardiac surgery from Jan 1, 2000, to Sept 30, 2007. Of these patients, 9106 were included in the retrospective observational study analysis. With propensity-adjusted, multivariate staged logistic regression, we analysed separately the incidence of renal dysfunction in patients receiving aprotinin, tranexamic acid, or no antifibrinolytic treatment in the presence or absence of preoperative ACE inhibitor treatment, for both on-pump and off-pump surgical techniques. FINDINGS: In 5434 patients undergoing on-pump cardiac surgery, the odds ratio (OR) between aprotinin and an increased risk of renal dysfunction without ACE inhibitor was 1.81 (95% CI 0.79-4.13, p=0.162) and with ACE inhibitor 1.73 (0.56-5.32, p=0.342). In the 848 patients taking ACE inhibitors and undergoing off-pump cardiac surgery, aprotinin was associated with a greater than two-fold increase in the risk of renal dysfunction after off-pump cardiac surgery (OR 2.87 [1.25-6.58], p=0.013). INTERPRETATION: Our results have shown that aprotinin seems to be safe during on-pump cardiac surgery. However, the combination of aprotinin and ACE inhibitors during off-pump cardiac surgery is associated with a significant risk of postoperative renal dysfunction.