; POISE-2 Investigators. Rationale and design of the PeriOperative ISchemic Evaluation-2 (POISE-2) trial: an international 2 × 2 factorial randomized controlled trial of acetyl-salicylic acid vs. placebo and clonidine vs. placebo in patients undergoing noncardiac surgery

Perioperative aspirin and coronary artery bypass graft surgery: An updated meta-analysis of randomized controlled trials

BACKGROUND

The decision to continue aspirin before elective coronary artery bypass graft surgery remains contentious because of competing thrombotic and bleeding risks. We performed a contemporary systematic review and meta-analysis to compare outcomes between patients undergoing coronary artery bypass grafting who stopped and continued aspirin before surgery.

METHODS

PubMed, MEDLINE, and CENTRAL databases were searched from inception to 4 October 2023 for randomized controlled trials comparing patients undergoing coronary artery bypass grafting who continued preoperative aspirin with those who discontinued before surgery. Studies with cointervention arms and multivariable-adjusted or propensity matched observational studies were excluded. Summary odds ratios were calculated using a random effects model for dichotomous and continuous variables. Subgroup and sensitivity analyses were conducted in order to explore sources of heterogeneity.

RESULTS

Fifteen eligible randomized controlled trials were included with a total of 6,188 patients. Patients who continued aspirin demonstrated no significant difference in all-cause mortality (odds ratio, 1.37; confidence interval, 0.81-2.33), perioperative myocardial infarction (odds ratio, 0.81; confidence interval, 0.55-1.18), and postoperative blood loss (mean difference, 66.12 mL; confidence interval, -1.45 to 133.69). No significant difference was observed between low-dose and greater doses of aspirin. There was minimal heterogeneity amongst included studies (I2 = 0%, P = .97, I2 = 33%, P = .13, and I2= 76, P = .06, respectively). Studies were of low methodologic quality according to Cochrane Risk of Bias for Randomized Trials.

CONCLUSIONS

This largest to-date systematic review and meta-analysis found no significant difference for risk of all-cause mortality, perioperative myocardial infarction, and postoperative bleeding between patients continuing and stopping aspirin before coronary artery bypass grafting.

The effect of anti-thrombotics on the postoperative bleeding rate in patients undergoing craniotomy for brain tumor

OBJECTIVE

The peak prevalence of many brain tumors is in elderly patients. These patients are often treated with platelet inhibitors (PIs) or anticoagulants (ACs), creating a challenge for neurosurgeons concerning the perioperative management. The aim of this study is to analyze the effect of PI/AC treatment on the postoperative bleeding rates in patients undergoing craniotomy due to a brain tumor.

METHODS

Retrospective analysis of 415 consecutive patients undergoing craniotomy/craniectomy due to a brain tumor. Ninety-nine patients with PI/AC treatment (PI/AC group consisting of 64 PI, 29 AC, and six multiple) and 316 patients without PI/AC (control group) were primarily compared for hemorrhage rate. Secondary outcome measures were clinical outcome and mortality. The association between short preoperative discontinuation (≤5 days), early postoperative resumption time (≤5 days), as well as short total discontinuation time (≤5 days) of PI/AC and postoperative bleeding rates was analyzed.

RESULTS

Postoperative bleeding rates were comparable between the groups (12.2% and 13.5% in the PI/AC and control group, respectively; p=.74). The majority of bleeds were asymptomatic (85.2%). No significant difference in the postoperative mortality rate was observed (1.0% and 1.6% in the PI/AC and the control group, respectively; p=.67). Shorter discontinuation time of PI/AC was not significantly associated with higher postoperative bleeding rates (preoperative: 12.1% vs. 12.3%; p=.94, postoperative: 11.1% vs. 12.5%, respectively; p=.87, total: 16.7% vs. 12%, respectively; p=.73).

CONCLUSIONS

Patients treated with PI/AC undergoing craniotomy for the resection of brain tumor do not seem to have increased rates of postoperative bleeding or mortality. We did not find a significant correlation between short discontinuation time of PI/AC in the perioperative period and postoperative bleeding.

Patient blood management in major digestive surgery: Recommendations from the Italian multisociety (ACOI, SIAARTI, SIdEM, and SIMTI) modified Delphi consensus conference

Patient blood management (PBM) is defined as the timely application of evidence-based medical and surgical concepts designed to maintain a surgical patient’s hemoglobin concentration, optimize hemostasis, and minimize blood loss in an effort to improve the outcomes. PBM is able to reduce mortality up to 68%, reoperation up to 43%, readmission up to 43%, composite morbidity up to 41%, infection rate up to 80%, average length of stay by 16%–33%, transfusion from 10% to 95%, and costs from 10% to 84% after major surgery. It should be noticed, however, that the process of PBM implementation is still in its infancy, and that its potential to improve perioperative outcomes could be strictly linked to the degree of adherence/compliance to the whole program, with decoupling and noncompliance being significant factors for failure. Therefore, the steering committees of four major Italian scientific societies, representing general surgeons, anesthesiologists and transfusion medicine specialists (Associazione Chirurghi Ospedalieri Italiani; Società Italiana di Anestesia, Analgesia, Rianimazione e Terapia Intensiva; Società Italiana di Emaferesi e Manipolazione Cellulare; Società Italiana di Medicina Trasfusionale e Immunoematologia), organized a joint modified Delphi consensus conference on PBM in the field of major digestive surgery (upper and lower gastrointestinal tract, and hepato-biliopancreatic resections), whose results and recommendations are herein presented.

Antiplatelet agents for chronic kidney disease

BACKGROUND

Antiplatelet agents are widely used to prevent cardiovascular events. The risks and benefits of antiplatelet agents may be different in people with chronic kidney disease (CKD) for whom occlusive atherosclerotic events are less prevalent, and bleeding hazards might be increased. This is an update of a review first published in 2013.

OBJECTIVES

To evaluate the benefits and harms of antiplatelet agents in people with any form of CKD, including those with CKD not receiving renal replacement therapy, patients receiving any form of dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 July 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We selected randomised controlled trials of any antiplatelet agents versus placebo or no treatment, or direct head-to-head antiplatelet agent studies in people with CKD. Studies were included if they enrolled participants with CKD, or included people in broader at-risk populations in which data for subgroups with CKD could be disaggregated.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted data from primary study reports and any available supplementary information for study population, interventions, outcomes, and risks of bias. Risk ratios (RR) and 95% confidence intervals (CI) were calculated from numbers of events and numbers of participants at risk which were extracted from each included study. The reported RRs were extracted where crude event rates were not provided. Data were pooled using the random-effects model. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 113 studies, enrolling 51,959 participants; 90 studies (40,597 CKD participants) compared an antiplatelet agent with placebo or no treatment, and 29 studies (11,805 CKD participants) directly compared one antiplatelet agent with another. Fifty-six new studies were added to this 2021 update. Seven studies originally excluded from the 2013 review were included, although they had a follow-up lower than two months. Random sequence generation and allocation concealment were at low risk of bias in 16 and 22 studies, respectively. Sixty-four studies reported low-risk methods for blinding of participants and investigators; outcome assessment was blinded in 41 studies. Forty-one studies were at low risk of attrition bias, 50 studies were at low risk of selective reporting bias, and 57 studies were at low risk of other potential sources of bias. Compared to placebo or no treatment, antiplatelet agents probably reduces myocardial infarction (18 studies, 15,289 participants: RR 0.88, 95% CI 0.79 to 0.99, I² = 0%; moderate certainty). Antiplatelet agents has uncertain effects on fatal or nonfatal stroke (12 studies, 10.382 participants: RR 1.01, 95% CI 0.64 to 1.59, I² = 37%; very low certainty) and may have little or no effect on death from any cause (35 studies, 18,241 participants: RR 0.94, 95 % CI 0.84 to 1.06, I² = 14%; low certainty). Antiplatelet therapy probably increases major bleeding in people with CKD and those treated with haemodialysis (HD) (29 studies, 16,194 participants: RR 1.35, 95% CI 1.10 to 1.65, I² = 12%; moderate certainty). In addition, antiplatelet therapy may increase minor bleeding in people with CKD and those treated with HD (21 studies, 13,218 participants: RR 1.55, 95% CI 1.27 to 1.90, I² = 58%; low certainty). Antiplatelet treatment may reduce early dialysis vascular access thrombosis (8 studies, 1525 participants) RR 0.52, 95% CI 0.38 to 0.70; low certainty). Antiplatelet agents may reduce doubling of serum creatinine in CKD (3 studies, 217 participants: RR 0.39, 95% CI 0.17 to 0.86, I² = 8%; low certainty). The treatment effects of antiplatelet agents on stroke, cardiovascular death, kidney failure, kidney transplant graft loss, transplant rejection, creatinine clearance, proteinuria, dialysis access failure, loss of primary unassisted patency, failure to attain suitability for dialysis, need of intervention and cardiovascular hospitalisation were uncertain. Limited data were available for direct head-to-head comparisons of antiplatelet drugs, including prasugrel, ticagrelor, different doses of clopidogrel, abciximab, defibrotide, sarpogrelate and beraprost.

AUTHORS' CONCLUSIONS

Antiplatelet agents probably reduced myocardial infarction and increased major bleeding, but do not appear to reduce all-cause and cardiovascular death among people with CKD and those treated with dialysis. The treatment effects of antiplatelet agents compared with each other are uncertain.

Risk of stroke and other adverse outcomes in patients with perioperative atrial fibrillation 1 year after non-cardiac surgery

AIMS

To determine the 1-year risk of stroke and other adverse outcomes in patients with a new diagnosis of perioperative atrial fibrillation (POAF) after non-cardiac surgery.

METHODS AND RESULTS

The PeriOperative ISchemic Evaluation (POISE)-1 trial evaluated the effects of metoprolol vs. placebo in 8351 patients, and POISE-2 compared the effect of aspirin vs. placebo, and clonidine vs. placebo in 10 010 patients. These trials included patients with, or at risk of, cardiovascular disease who were undergoing non-cardiac surgery. For the purpose of this study, we combined the POISE datasets, excluding 244 patients who were in atrial fibrillation (AF) at the time of randomization. Perioperative atrial fibrillation was defined as new AF that occurred within 30 days after surgery. Our primary outcome was the incidence of stroke at 1 year of follow-up; secondary outcomes were mortality and myocardial infarction (MI). We compared outcomes among patients with and without POAF using multivariable adjusted Cox proportional hazards models. Among 18 117 patients (mean age 69 years, 57.4% male), 404 had POAF (2.2%). The stroke incidence 1 year after surgery was 5.58 vs. 1.54 per 100 patient-years in patients with and without POAF, adjusted hazard ratio (aHR) 3.43, 95% confidence interval (CI) 2.00-5.90; P < 0.001. Patients with POAF also had an increased risk of death (incidence 31.37 vs. 9.34; aHR 2.51, 95% CI 2.01-3.14; P < 0.001) and MI (incidence 26.20 vs. 8.23; aHR 5.10, 95% CI 3.91-6.64; P < 0.001).

CONCLUSION

Patients with POAF have a significantly increased risk of stroke, MI, and death at 1 year. Intervention studies are needed to evaluate risk reduction strategies in this high-risk population.

Actual Issues of the Cardiac Complications Risk Assessment and Correction in Non-Cardiac Surgery

Worldwide, more than 200 million non-cardiac surgeries are performed annually, and this number is constantly increasing; cardiac complications are the leading cause of death in such surgeries. So, in a multicenter study conducted in 27 countries, cardiovascular complications were present in 68% of cases of death in the postoperative period. Registers of recent years have shown that the number of such complications remains high, for example, with a dynamic assessment of troponins, perioperative myocardial damage was detected in 13-18% of cases. This review provides a critical analysis of the step-by-step algorithm for assessing cardiac risk of non-cardiac operations considering the emergence of new publications on this topic. The review discusses new data on risk assessment scales, functional state assessment, the use of non-invasive tests, biomarkers, the role of preventive myocardial revascularization in the preoperative period, and drug therapy. The issues of non-cardiac operations after percutaneous coronary intervention, perioperative myocardial damage are considered separately. The review emphasizes the difficulties in obtaining evidence, conducting randomized clinical trials in this section of medicine, which do not allow obtaining unambiguous conclusions in most cases and lead to inconsistencies and ambiguities in the recommendations of various expert groups. This review will help practitioners navigate this issue and help to use the optimal diagnostic and treatment strategy before performing non-cardiac surgery.

One-year Results of a Factorial Randomized Trial of Aspirin versus Placebo and Clonidine versus Placebo in Patients Having Noncardiac Surgery

BACKGROUND

The authors previously reported that perioperative aspirin and/or clonidine does not prevent a composite of death or myocardial infarction 30 days after noncardiac surgery. Moreover, aspirin increased the risk of major bleeding and clonidine caused hypotension and bradycardia. Whether these complications produce harm at 1 yr remains unknown.

METHODS

The authors randomized 10,010 patients with or at risk of atherosclerosis and scheduled for noncardiac surgery in a 1:1:1:1 ratio to clonidine/aspirin, clonidine/aspirin placebo, clonidine placebo/aspirin, or clonidine placebo/aspirin placebo. Patients started taking aspirin or placebo just before surgery; those not previously taking aspirin continued daily for 30 days, and those taking aspirin previously continued for 7 days. Patients were also randomly assigned to receive clonidine or placebo just before surgery, with the study drug continued for 72 h.

RESULTS

Neither aspirin nor clonidine had a significant effect on the primary 1-yr outcome, a composite of death or nonfatal myocardial infarction, with a 1-yr hazard ratio for aspirin of 1.00 (95% CI, 0.89 to 1.12; P = 0.948; 586 patients [11.8%] vs. 589 patients [11.8%]) and a hazard ratio for clonidine of 1.07 (95% CI, 0.96 to 1.20; P = 0.218; 608 patients [12.1%] vs. 567 patients [11.3%]), with effect on death or nonfatal infarction. Reduction in death and nonfatal myocardial infarction from aspirin in patients who previously had percutaneous coronary intervention at 30 days persisted at 1 yr. Specifically, the hazard ratio was 0.58 (95% CI, 0.35 to 0.95) in those with previous percutaneous coronary intervention and 1.03 (95% CI, 0.91to 1.16) in those without (interaction P = 0.033). There was no significant effect of either drug on death, cardiovascular complications, cancer, or chronic incisional pain at 1 yr (all P > 0.1).

CONCLUSIONS

Neither perioperative aspirin nor clonidine have significant long-term effects after noncardiac surgery. Perioperative aspirin in patients with previous percutaneous coronary intervention showed persistent benefit at 1 yr, a plausible sub-group effect.

Effects of peri-operative nonsteroidal anti-inflammatory drugs on post-operative kidney function for adults with normal kidney function

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) provide effective analgesia during the post-operative period but can cause acute kidney injury (AKI) when used peri-operatively (at or around the time of surgery). This is an update of a Cochrane review published in 2007.

OBJECTIVES

This review looked at the effect of NSAIDs used in the peri-operative period on post-operative kidney function in patients with normal kidney function.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 4 January 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Specialised Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs (RCTs in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth or other predictable methods) looking at the use of NSAIDs versus placebo for the treatment of post-operative pain in patients with normal kidney function were included.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out independently by two authors as was assessment of risk of bias. Disagreements were resolved by a third author. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) together with their 95% confidence intervals (CI). Meta-analyses were used to assess the outcomes of AKI, change in serum creatinine (SCr), urine output, renal replacement therapy (RRT), death (all causes) and length of hospital stay.

MAIN RESULTS

We identified 26 studies (8835 participants). Risk of bias was high in 17, unclear in 6and low in three studies. There was high risk of attrition bias in six studies.Only two studies measured AKI. The use of NSAIDs had uncertain effects on the incidence of AKI compared to placebo (7066 participants: RR 1.79, 95% CI 0.40 to 7.96; I2 = 59%; very low certainty evidence). One study was stopped early by the data monitoring committee due to increased rates of AKI in the NSAID group. Moreover, both of these studies were examining NSAIDs for indications other than analgesia and therefore utilised relatively low doses.Compared to placebo, NSAIDs may slightly increase serum SCr (15 studies, 794 participants: MD 3.23 μmol/L, 95% CI -0.80 to 7.26; I2 = 63%; low certainty evidence). Studies displayed moderate to high heterogeneity and had multiple exclusion criteria including age and so were not representative of patients undergoing surgery. Three of these studies excluded patients if their creatinine rose post-operatively.NSAIDs may make little or no difference to post-operative urine output compared to placebo (6 studies, 149 participants: SMD -0.02, 95% CI -0.31 to 0.27). No reliable conclusions could be drawn from these studies due to the differing units of measurements and measurement time points.It is uncertain whether NSAIDs leads to the need for RRT because the certainty of this evidence is very low (2 studies, 7056 participants: RR 1.57, 95% CI 0.49 to 5.07; I2 = 26%); there were few events and the results were inconsistent.It is uncertain whether NSAIDs lead to more deaths (2 studies, 312 participants: RR 1.44, 95% CI 0.19 to 11.12; I2 = 38%) or increased the length of hospital stay (3 studies, 410 participants: MD 0.12 days, 95% CI -0.48 to 0.72; I2 = 24%).

AUTHORS' CONCLUSIONS

Overall NSAIDs had uncertain effects on the risk of post-operative AKI, may slightly increase post-operative SCr, and it is uncertain whether NSAIDs lead to the need for RRT, death or increases the length of hospital stay. The available data therefore does not confirm the safety of NSAIDs in patients undergoing surgery. Further larger studies using the Kidney Disease Improving Global Outcomes definition for AKI including patients with co-morbidities are required to confirm these findings. .

Effect of aspirin in vascular surgery in patients from a randomized clinical trial (POISE-2)

BACKGROUND

In the POISE-2 (PeriOperative ISchemic Evaluation 2) trial, perioperative aspirin did not reduce cardiovascular events, but increased major bleeding. There remains uncertainty regarding the effect of perioperative aspirin in patients undergoing vascular surgery. The aim of this substudy was to determine whether there is a subgroup effect of initiating or continuing aspirin in patients undergoing vascular surgery.

METHODS

POISE-2 was a blinded, randomized trial of patients having non-cardiac surgery. Patients were assigned to perioperative aspirin or placebo. The primary outcome was a composite of death or myocardial infarction at 30 days. Secondary outcomes included: vascular occlusive complications (a composite of amputation and peripheral arterial thrombosis) and major or life-threatening bleeding.

RESULTS

Of 10 010 patients in POISE-2, 603 underwent vascular surgery, 319 in the continuation and 284 in the initiation stratum. Some 272 patients had vascular surgery for occlusive disease and 265 had aneurysm surgery. The primary outcome occurred in 13·7 per cent of patients having aneurysm repair allocated to aspirin and 9·0 per cent who had placebo (hazard ratio (HR) 1·48, 95 per cent c.i. 0·71 to 3·09). Among patients who had surgery for occlusive vascular disease, 15·8 per cent allocated to aspirin and 13·6 per cent on placebo had the primary outcome (HR 1·16, 0·62 to 2·17). There was no interaction with the primary outcome for type of surgery (P = 0·294) or aspirin stratum (P = 0·623). There was no interaction for vascular occlusive complications (P = 0·413) or bleeding (P = 0·900) for vascular compared with non-vascular surgery.

CONCLUSION

This study suggests that the overall POISE-2 results apply to vascular surgery. Perioperative withdrawal of chronic aspirin therapy did not increase cardiovascular or vascular occlusive complications. Registration number: NCT01082874 ( http://www.clinicaltrials.gov).

Perioperative myocardial injury and the contribution of hypotension

Mortality in the month following surgery is about 1000 times greater than anesthesia-related intraoperative mortality, and myocardial injury appears to be the leading cause. There is currently no known safe prophylaxis for postoperative myocardial injury, but there are strong associations among hypotension and myocardial injury, renal injury, and death. During surgery, the harm threshold is a mean arterial pressure of about 65 mmHg. In critical care units, the threshold appears to be considerably greater, perhaps 90 mmHg. The threshold triggering injury on surgical wards remains unclear but may be in between. Much of the association between hypotension and serious complications surely results from residual confounding, but sparse randomized data suggest that at least some harm can be prevented by intervening to limit hypotension. Reducing hypotension may therefore improve perioperative outcomes.

Preoperative platelet transfusions to reverse antiplatelet therapy for urgent non-cardiac surgery: an observational cohort study

Essentials An increasing number of patients requiring surgery receive antiplatelet therapy (APT). We analyzed 181 patients receiving presurgery platelet transfusions to reverse APT. No coronary thrombosis occurred after platelet transfusion. This justifies a prospective trial to test preoperative platelet transfusions to reverse APT.

SUMMARY

Background Patients receiving antiplatelet therapy (APT) have an increased risk of perioperative bleeding and cardiac adverse events (CAE). Preoperative platelet transfusions may reduce the bleeding risk but may also increase the risk of CAE, particularly coronary thrombosis in patients after recent stent implantation. Objectives To analyze the incidence of perioperative CAE and bleeding in patients undergoing non-cardiac surgery using a standardized management of transfusing two platelet concentrates preoperatively and restart of APT within 24-72 h after surgery. Methods A cohort of consecutive patients on APT treated with two platelet concentrates before non-cardiac surgery between January 2012 and December 2014 was retrospectively identified. Patients were stratified by the risk of major adverse cardiac and cerebrovascular events (MACCE). The primary objective was the incidence of CAE (myocardial infarction, acute heart failure and cardiac troponine T increase). Secondary objectives were incidences of other thromboembolic events, bleedings, transfusions and mortality. Results Among 181 patients, 88 received aspirin, 21 clopidogrel and 72 dual APT. MACCE risk was high in 63, moderate in 103 and low in 15 patients; 67 had cardiac stents. Ten patients (5.5%; 95% CI, 3.0-9.9%) developed a CAE (three myocardial infarctions, four cardiac failures and three troponin T increases). None was caused by coronary thrombosis. Surgery-related bleeding occurred in 22 patients (12.2%; 95% CI, 8.2-17.7%), making 12 re-interventions necessary (6.6%; 95% CI, 3.8-11.2%). Conclusion Preoperative platelet transfusions and early restart of APT allowed urgent surgery and did not cause coronary thromboses, but non-thrombotic CAEs and re-bleeding occurred. Randomized trials are warranted to test platelet transfusion against other management strategies.

Alpha-2 adrenergic agonists for the prevention of cardiac complications among adults undergoing surgery

BACKGROUND

The surgical stress response plays an important role on the pathogenesis of perioperative cardiac complications. Alpha-2 adrenergic agonists attenuate this response and may help prevent postoperative cardiac complications.

OBJECTIVES

To determine the efficacy and safety of α-2 adrenergic agonists for reducing mortality and cardiac complications in adults undergoing cardiac surgery and non-cardiac surgery.

SEARCH METHODS

We searched CENTRAL (2017, Issue 4), MEDLINE (1950 to April Week 4, 2017), Embase (1980 to May 2017), the Science Citation Index, clinical trial registries, and reference lists of included articles.

SELECTION CRITERIA

We included randomized controlled trials that compared α-2 adrenergic agonists (i.e. clonidine, dexmedetomidine or mivazerol) against placebo or non-α-2 adrenergic agonists. Included trials had to evaluate the efficacy and safety of α-2 adrenergic agonists for preventing perioperative mortality or cardiac complications (or both), or measure one or more relevant outcomes (i.e. death, myocardial infarction, heart failure, acute stroke, supraventricular tachyarrhythmia and myocardial ischaemia).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality, extracted data and independently performed computer entry of abstracted data. We contacted study authors for additional information. Adverse event data were gathered from the trials. We evaluated included studies using the Cochrane 'Risk of bias' tool, and the quality of the evidence underlying pooled treatment effects using GRADE methodology. Given the clinical heterogeneity between cardiac and non-cardiac surgery, we analysed these subgroups separately. We expressed treatment effects as pooled risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We included 47 trials with 17,039 participants. Of these studies, 24 trials only included participants undergoing cardiac surgery, 23 only included participants undergoing non-cardiac surgery and eight only included participants undergoing vascular surgery. The α-2 adrenergic agonist studied was clonidine in 21 trials, dexmedetomidine in 24 trials and mivazerol in two trials.In non-cardiac surgery, there was high quality evidence that α-2 adrenergic agonists led to a similar risk of all-cause mortality compared with control groups (1.3% with α-2 adrenergic agonists versus 1.7% with control; RR 0.80, 95% CI 0.61 to 1.04; participants = 14,081; studies = 16). Additionally, the risk of cardiac mortality was similar between treatment groups (0.8% with α-2 adrenergic agonists versus 1.0% with control; RR 0.86, 95% CI 0.60 to 1.23; participants = 12,525; studies = 5, high quality evidence). The risk of myocardial infarction was probably similar between treatment groups (RR 0.94, 95% CI 0.69 to 1.27; participants = 13,907; studies = 12, moderate quality evidence). There was no associated effect on the risk of stroke (RR 0.93, 95% CI 0.55 to 1.56; participants = 11,542; studies = 7; high quality evidence). Conversely, α-2 adrenergic agonists probably increase the risks of clinically significant bradycardia (RR 1.59, 95% CI 1.18 to 2.13; participants = 14,035; studies = 16) and hypotension (RR 1.24, 95% CI 1.03 to 1.48; participants = 13,738; studies = 15), based on moderate quality evidence.There was insufficient evidence to determine the effect of α-2 adrenergic agonists on all-cause mortality in cardiac surgery (RR 0.52, 95% CI 0.26 to 1.04; participants = 1947; studies = 16) and myocardial infarction (RR 1.01, 95% CI 0.43 to 2.40; participants = 782; studies = 8), based on moderate quality evidence. There was one cardiac death in the clonidine arm of a study of 22 participants. Based on very limited data, α-2 adrenergic agonists may have reduced the risk of stroke (RR 0.37, 95% CI 0.15 to 0.93; participants = 1175; studies = 7; outcome events = 18; low quality evidence). Conversely, α-2 adrenergic agonists increased the risk of bradycardia from 6.4% to 12.0% (RR 1.88, 95% CI 1.35 to 2.62; participants = 1477; studies = 10; moderate quality evidence), but their effect on hypotension was uncertain (RR 1.19, 95% CI 0.87 to 1.64; participants = 1413; studies = 9; low quality evidence).These results were qualitatively unchanged in subgroup analyses and sensitivity analyses.

AUTHORS' CONCLUSIONS

Our review concludes that prophylactic α-2 adrenergic agonists generally do not prevent perioperative death or major cardiac complications. For non-cardiac surgery, there is moderate-to-high quality evidence that these agents do not prevent death, myocardial infarction or stroke. Conversely, there is moderate quality evidence that these agents have important adverse effects, namely increased risks of hypotension and bradycardia. For cardiac surgery, there is moderate quality evidence that α-2 adrenergic agonists have no effect on the risk of mortality or myocardial infarction, and that they increase the risk of bradycardia. The quality of evidence was inadequate to draw conclusions regarding the effects of alpha-2 agonists on stroke or hypotension during cardiac surgery.

Aspirin in Patients With Previous Percutaneous Coronary Intervention Undergoing Noncardiac Surgery

BACKGROUND

Uncertainty remains about the effects of aspirin in patients with prior percutaneous coronary intervention (PCI) having noncardiac surgery.

OBJECTIVE

To evaluate benefits and harms of perioperative aspirin in patients with prior PCI.

DESIGN

Nonprespecified subgroup analysis of a multicenter factorial trial. Computerized Internet randomization was done between 2010 and 2013. Patients, clinicians, data collectors, and outcome adjudicators were blinded to treatment assignment. (ClinicalTrials.gov: NCT01082874).

SETTING

135 centers in 23 countries.

PATIENTS

Adults aged 45 years or older who had or were at risk for atherosclerotic disease and were having noncardiac surgery. Exclusions were placement of a bare-metal stent within 6 weeks, placement of a drug-eluting stent within 1 year, or receipt of nonstudy aspirin within 72 hours before surgery.

INTERVENTION

Aspirin therapy (overall trial, n = 4998; subgroup, n = 234) or placebo (overall trial, n = 5012; subgroup, n = 236) initiated within 4 hours before surgery and continued throughout the perioperative period. Of the 470 subgroup patients, 99.9% completed follow-up.

MEASUREMENTS

The 30-day primary outcome was death or nonfatal myocardial infarction; bleeding was a secondary outcome.

RESULTS

In patients with prior PCI, aspirin reduced the risk for the primary outcome (absolute risk reduction, 5.5% [95% CI, 0.4% to 10.5%]; hazard ratio [HR], 0.50 [CI, 0.26 to 0.95]; P for interaction = 0.036) and for myocardial infarction (absolute risk reduction, 5.9% [CI, 1.0% to 10.8%]; HR, 0.44 [CI, 0.22 to 0.87]; P for interaction = 0.021). The effect on the composite of major and life-threatening bleeding in patients with prior PCI was uncertain (absolute risk increase, 1.3% [CI, -2.6% to 5.2%]). In the overall population, aspirin increased the risk for major bleeding (absolute risk increase, 0.8% [CI, 0.1% to 1.6%]; HR, 1.22 [CI, 1.01 to 1.48]; P for interaction = 0.50).

LIMITATION

Nonprespecified subgroup analysis with small sample.

CONCLUSION

Perioperative aspirin may be more likely to benefit rather than harm patients with prior PCI.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research.

Use of aspirin and bleeding-related complications after hepatic resection

Background

The operative risk of hepatectomy under antiplatelet therapy is unknown. This study sought to assess the outcomes of elective hepatectomy performed with or without aspirin continuation in a well balanced matched cohort.

Methods

Data were retrieved from a multicentre prospective observational study. Aspirin and control groups were compared by non-standardized methods and by propensity score (PS) matching analysis. The main outcome was severe (Dindo–Clavien grade IIIa or more) haemorrhage. Other outcomes analysed were intraoperative transfusion, overall haemorrhage, major morbidity, comprehensive complication index (CCI) score, thromboembolic complications, ischaemic complications and mortality.

Results

Before matching, there were 118 patients in the aspirin group and 1685 in the control group. ASA fitness grade, cardiovascular disease, previous history of angina pectoris, angioplasty, diabetes, use of vitamin K antagonists, cirrhosis and type of hepatectomy were significantly different between the groups. After PS matching, 108 patients were included in each group. There were no statistically significant differences between the aspirin and control groups in severe haemorrhage (6·5 versus 5·6 per cent respectively; odds ratio (OR) 1·18, 95 per cent c.i. 0·38 to 3·62), intraoperative transfusion (23·4 versus 23·7 per cent; OR 0·98, 0·51 to 1·87), overall haemorrhage (10·2 versus 12·0 per cent; OR 0·83, 0·35 to 1·94), CCI score (24 versus 28; P = 0·520), major complications (23·1 versus 13·9 per cent; OR 1·82, 0·92 to 3·79) and 90-day mortality (5·6 versus 4·6 per cent; OR 1·21, 0·36 to 4·09).

Conclusion

This observational study suggested that aspirin continuation is not associated with a higher rate of bleeding-related complications after elective hepatic surgery.

Period-dependent Associations between Hypotension during and for Four Days after Noncardiac Surgery and a Composite of Myocardial Infarction and Death

Background

The relative contributions of intraoperative and postoperative hypotension to perioperative morbidity remain unclear. We determined the association between hypotension and a composite of 30-day myocardial infarction and death over three periods: (1) intraoperative, (2) remaining day of surgery, and (3) during the initial four postoperative days.

Methods

This was a substudy of POISE-2, a 10,010-patient factorial-randomized trial of aspirin and clonidine for prevention of myocardial infarction. Clinically important hypotension was defined as systolic blood pressure less than 90 mmHg requiring treatment. Minutes of hypotension was the exposure variable intraoperatively and for the remaining day of surgery, whereas hypotension status was treated as binary variable for postoperative days 1 to 4. We estimated the average relative effect of hypotension across components of the composite using a distinct effect generalized estimating model, adjusting for hypotension during earlier periods.

Results

Among 9,765 patients, 42% experienced hypotension, 590 (6.0%) had an infarction, and 116 (1.2%) died within 30 days of surgery. Intraoperatively, the estimated average relative effect across myocardial infarction and mortality was 1.08 (98.3% CI, 1.03, 1.12; P &lt; 0.001) per 10-min increase in hypotension duration. For the remaining day of surgery, the odds ratio was 1.03 (98.3% CI, 1.01, 1.05; P &lt; 0.001) per 10-min increase in hypotension duration. The average relative effect odds ratio was 2.83 (98.3% CI, 1.26, 6.35; P = 0.002) in patients with hypotension during the subsequent four days of hospitalization.

Conclusions

Clinically important hypotension—a potentially modifiable exposure—was significantly associated with a composite of myocardial infarction and death during each of three perioperative periods, even after adjustment for previous hypotension.

Perioperative Aspirin for Prevention of Venous Thromboembolism: The PeriOperative ISchemia Evaluation-2 Trial and a Pooled Analysis of the Randomized Trials

BACKGROUND

The PeriOperative ISchemia Evaluation-2 (POISE-2) trial compared aspirin with placebo after noncardiac surgery.

METHODS

The authors randomly assigned 10,010 patients undergoing noncardiac surgery to receive 200 mg aspirin or placebo 2 to 4 h before surgery and then 100 mg aspirin daily or placebo daily for up to 30 days after surgery. Herein, the authors report the effect of aspirin on venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, as well as an updated pooled analysis of randomized trials of antiplatelet therapy for VTE prevention in noncardiac surgery patients.

RESULTS

Six thousand five hundred forty-eight patients (65.4%) received anticoagulant prophylaxis. VTE occurred in 53 patients (1.1%) allocated to aspirin and in 60 patients (1.2%) allocated to placebo (hazard ratio, 0.89; 95% CI, 0.61 to 1.28). Major or life-threatening bleeding occurred in 312 patients (6.3%) allocated to aspirin and in 256 patients (5.1%) allocated to placebo (hazard ratio, 1.22; 95% CI, 1.04 to 1.44). Concomitant use of anticoagulant prophylaxis did not modify the effect of aspirin on VTE or bleeding. Pooled analysis of the POISE-2 and Pulmonary Embolism Prevention trials demonstrated that symptomatic VTE occurred in 173 (1.3%) of 13,724 patients allocated to aspirin and in 246 (1.8%) of 13,730 patients allocated to placebo (odds ratio, 0.71; 95% CI, 0.56 to 0.89; heterogeneity P = 0.27; I = 17%); the impact of aspirin was very similar in those who did and did not receive pharmacologic prophylaxis. Pooled estimates for symptomatic VTE were similar to the pooled estimates for any deep vein thrombosis and pulmonary embolism from the POISE-2 trial, Pulmonary Embolism Prevention trial, and the Antiplatelet Trialists' Collaboration meta-analysis.

CONCLUSIONS

Aspirin in the POISE-2 trial did not reduce VTE, but two thirds of patients received anticoagulant prophylaxis, there were few VTE events, and results were consistent with a wide range of aspirin effects. A pooled analysis of the randomized trials demonstrates evidence for the efficacy of aspirin for VTE prevention in hospitalized surgical patients.

Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery

The Canadian Cardiovascular Society Guidelines Committee and key Canadian opinion leaders believed there was a need for up to date guidelines that used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system of evidence assessment for patients who undergo noncardiac surgery. Strong recommendations included: 1) measuring brain natriuretic peptide (BNP) or N-terminal fragment of proBNP (NT-proBNP) before surgery to enhance perioperative cardiac risk estimation in patients who are 65 years of age or older, are 45-64 years of age with significant cardiovascular disease, or have a Revised Cardiac Risk Index score ≥ 1; 2) against performing preoperative resting echocardiography, coronary computed tomography angiography, exercise or cardiopulmonary exercise testing, or pharmacological stress echocardiography or radionuclide imaging to enhance perioperative cardiac risk estimation; 3) against the initiation or continuation of acetylsalicylic acid for the prevention of perioperative cardiac events, except in patients with a recent coronary artery stent or who will undergo carotid endarterectomy; 4) against α₂ agonist or β-blocker initiation within 24 hours before surgery; 5) withholding angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker starting 24 hours before surgery; 6) facilitating smoking cessation before surgery; 7) measuring daily troponin for 48 to 72 hours after surgery in patients with an elevated NT-proBNP/BNP measurement before surgery or if there is no NT-proBNP/BNP measurement before surgery, in those who have a Revised Cardiac Risk Index score ≥1, age 45-64 years with significant cardiovascular disease, or age 65 years or older; and 8) initiating of long-term acetylsalicylic acid and statin therapy in patients who suffer myocardial injury/infarction after surgery.

Neuraxial block and postoperative epidural analgesia: effects on outcomes in the POISE-2 trial†

BACKGROUND

We assessed associations between intraoperative neuraxial block and postoperative epidural analgesia, and a composite primary outcome of death or non-fatal myocardial infarction, at 30 days post-randomization in POISE-2 Trial subjects.

METHODS

10 010 high-risk noncardiac surgical patients were randomized aspirin or placebo and clonidine or placebo. Neuraxial block was defined as intraoperative spinal anaesthesia, or thoracic or lumbar epidural anaesthesia. Postoperative epidural analgesia was defined as postoperative epidural local anaesthetic and/or opioid administration. We used logistic regression with weighting using estimated propensity scores.

RESULTS

Neuraxial block was not associated with the primary outcome [7.5% vs 6.5%; odds ratio (OR), 0.89; 95% CI (confidence interval), 0.73-1.08; P=0.24], death (1.0% vs 1.4%; OR, 0.84; 95% CI, 0.53-1.35; P=0.48), myocardial infarction (6.9% vs 5.5%; OR, 0.91; 95% CI, 0.74-1.12; P=0.36) or stroke (0.3% vs 0.4%; OR, 1.05; 95% CI, 0.44-2.49; P=0.91). Neuraxial block was associated with less clinically important hypotension (39% vs 46%; OR, 0.90; 95% CI, 0.81-1.00; P=0.04). Postoperative epidural analgesia was not associated with the primary outcome (11.8% vs 6.2%; OR, 1.48; 95% CI, 0.89-2.48; P=0.13), death (1.3% vs 0.8%; OR, 0.84; 95% CI, 0.35-1.99; P=0.68], myocardial infarction (11.0% vs 5.7%; OR, 1.53; 95% CI, 0.90-2.61; P=0.11], stroke (0.4% vs 0.4%; OR, 0.65; 95% CI, 0.18-2.32; P=0.50] or clinically important hypotension (63% vs 36%; OR, 1.40; 95% CI, 0.95-2.09; P=0.09).

CONCLUSIONS

Neuraxial block and postoperative epidural analgesia were not associated with adverse cardiovascular outcomes among POISE-2 subjects.

Perioperative aspirin management after POISE-2: some answers, but questions remain

Aspirin constitutes important uninterrupted lifelong therapy for many patients with cardiovascular (CV) disease or significant (CV) risk factors. However, whether aspirin should be continued or withheld in patients undergoing noncardiac surgery is a common clinical conundrum that balances the potential of aspirin for decreasing thrombotic risk with its possibility for increasing perioperative blood loss. In this focused review, we describe the role of aspirin in treating and preventing cardiovascular disease, summarize the most important literature on the perioperative use of aspirin (including the recently published PeriOperative ISchemic Evaluation [POISE]-2 trial), and offer current recommendations for managing aspirin during the perioperative period. POISE-2 suggests that aspirin administration during the perioperative period does not change the risk of a cardiovascular event and may result in increased bleeding. However, these findings are tempered by a number of methodological issues related to the study. On the basis of currently available literature, including POISE-2, aspirin should not be administered to patients undergoing surgery unless there is a definitive guideline-based primary or secondary prevention indication. Aside from closed-space procedures, intramedullary spine surgery, or possibly prostate surgery, moderate-risk patients taking lifelong aspirin for a guideline-based primary or secondary indication may warrant continuation of their aspirin throughout the perioperative period.