Should clopidogrel be discontinued before coronary artery bypass grafting for patients with acute coronary syndrome? A systematic review and meta-analysis

Effect of topical application of autologous platelet gel on sternal wound infection after cardiac surgery: A meta-analysis

Following heart operation, a severe life-threatening complication has been identified by investigators who have recently discovered that local application of platelet-rich plasma (PRP) can lower the rate of wound infection in heart surgery. Nevertheless, due to the low quality of these trials, we have tried to perform high-quality meta-analyses to prove the efficacy of PRP in heart surgery for post-operative wound infections. In this study, five randomised controlled trials (RCTs) were chosen from three databases, and there were 1005 studies to analyse the data. Among 181 cases, PRP was applied to the surgical site, and 205 in the control group. Both the CI and the OR or the average difference (MD) were computed with either a fixed or random-effect model. A meta-analysis of the data was carried out with RevMan 5.3. The results showed that there were no statistically significant differences in the incidence of post-operative surgical site infection (SSI) in control group compared to those treated with PRP gel (OR, 0.97; 95% CI, 0.38, 2.47; p = 0.95); In the heart operation, the local application of PRP gel decreased the rate of drainage after operation (MD, -217.82; 95% CI, -335.38, -100.26; p = 0.0003); The operation time of the PRP gel was not significantly different from that of the control group (MD, 12.65; 95% CI, -2.95, 28.24; p = 0.11). Contrary to earlier research, the application of autoplatelet gel in heart surgery did not seem to decrease operative site infections after the operation, but it did decrease the amount of postoperative drainage. Nevertheless, because of the limited number of RCTs in this meta-analysis, caution should be exercised in their treatment. More high-quality randomised, large-sample trials are required to further confirm the findings.

Peri-procedure management of antithrombotic agents and thrombocytopenia for common procedures in oncology: Guidance from the SSC of the ISTH

Patients with cancer have an increased risk of thrombosis requiring anticoagulants and/or antiplatelet agents, and they can also encounter thrombocytopenia due to cancer itself or cancer therapies. They often undergo many procedures such as tissue or bone marrow biopsies, placement of central access lines, diagnostic or therapeutic draining procedures, lumbar puncture, and more. Management of antithrombotic agents or thrombocytopenia around the time of these procedures is highly variable. In this document, the Hemostasis and Malignancy Subcommittee of the International Society on Thrombosis and Haemostasis aims to provide useful practice guidance in the management of antithrombotic agents and thrombocytopenia around the time of common procedures in patients with cancer.

Perioperative Management of Antithrombotic Therapy: An American College of Chest Physicians Clinical Practice Guideline

BACKGROUND

The American College of Chest Physicians Clinical Practice Guideline on the Perioperative Management of Antithrombotic Therapy addresses 43 Patients-Interventions-Comparators-Outcomes (PICO) questions related to the perioperative management of patients who are receiving long-term oral anticoagulant or antiplatelet therapy and require an elective surgery/procedure. This guideline is separated into four broad categories, encompassing the management of patients who are receiving: (1) a vitamin K antagonist (VKA), mainly warfarin; (2) if receiving a VKA, the use of perioperative heparin bridging, typically with a low-molecular-weight heparin; (3) a direct oral anticoagulant (DOAC); and (4) an antiplatelet drug.

METHODS

Strong or conditional practice recommendations are generated based on high, moderate, low, and very low certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology for clinical practice guidelines.

RESULTS

A multidisciplinary panel generated 44 guideline recommendations for the perioperative management of VKAs, heparin bridging, DOACs, and antiplatelet drugs, of which two are strong recommendations: (1) against the use of heparin bridging in patients with atrial fibrillation; and (2) continuation of VKA therapy in patients having a pacemaker or internal cardiac defibrillator implantation. There are separate recommendations on the perioperative management of patients who are undergoing minor procedures, comprising dental, dermatologic, ophthalmologic, pacemaker/internal cardiac defibrillator implantation, and GI (endoscopic) procedures.

CONCLUSIONS

Substantial new evidence has emerged since the 2012 iteration of these guidelines, especially to inform best practices for the perioperative management of patients who are receiving a VKA and may require heparin bridging, for the perioperative management of patients who are receiving a DOAC, and for patients who are receiving one or more antiplatelet drugs. Despite this new knowledge, uncertainty remains as to best practices for the majority of perioperative management questions.

Perioperative Management of Antiplatelet Therapy: A Systematic Review and Meta-analysis

OBJECTIVE

To summarize the available evidence about the perioperative management of patients who are receiving long-term antiplatelet therapy and require elective surgery/procedures.

METHODS

This systematic review supports the development of the American College of Chest Physicians guideline on the perioperative management of antiplatelet therapy. A literature search of MEDLINE, EMBASE, Scopus and Cochrane databases was conducted from each database's inception to July 16, 2020. Meta-analyses were conducted when possible.

RESULTS

In patients receiving long-term antiplatelet therapy and undergoing elective noncardiac surgery, the available evidence did not show a significant difference in major bleeding between a shorter vs longer antiplatelet interruption, with low certainty of evidence (COE). Compared with patients who received placebo perioperatively, aspirin continuation was associated with increased risk of major bleeding (relative risk [RR], 1.31; 95% CI, 1.15-1.50; high COE) and lower risk of major thromboembolism (RR, 0.74; 95% CI, 0.58-0.94; moderate COE). During antiplatelet interruption, bridging with low-molecular-weight heparin was associated with increased risk of major bleeding compared with no bridging (RR, 1.86; 95% CI, 1.24-2.79; very low COE). Continuation of antiplatelets during minor dental and ophthalmologic procedures was not associated with a statistically significant difference in the risk of major bleeding (very low COE).

CONCLUSION

This systematic review summarizes the current evidence about the perioperative management of antiplatelet therapy and highlights the urgent need for further research, particularly with the increasing prevalence of patients taking 1 or more antiplatelet agents.

Novel autologous, high concentrated fibrin as advanced hemostatic agent for coronary surgery

BACKGROUND

Variability in transfusion outcomes and excessive postoperative bleeding represents a significant problem in cardiac surgery. The effort to reduce bleeding complications and transfusion outcomes is desirable. Our study investigated the feasibility of reducing bleeding complications and transfusion requirements by applying perioperatively prepared autologous bio-regenerative fibrin sealant.

METHODS

A prospective, case-control study enrolled 74 patients undergoing coronary artery bypass grafting by a single surgeon. Patients in the control group (N = 43), received traditional methods of hemostasis, while patients in the experimental group (N = 31) were treated additionally with autologous bio-regenerative fibrin.

RESULTS

Patients were well-matched with regard to basic demographic, laboratory and procedural data. Allogeneic blood transfusion requirement in control group was 39.5 % (17 of 43 patients), compared to 6.5 % (2 of 31 patients) in treated group (p < 0,001). The lower infection rate in the experimental group was also noted. No safety issues were identified during the preparation and application process.

CONCLUSION

Autologous bio-regenerative fibrin can be safely prepared, with no time consuming, and was demonstrated to be a useful tool to decrease allogeneic blood transfusion requirements following elective coronary artery bypass grafting surgery. A prospective randomized trial is needed to confirm these findings.

A systematic review of guidelines for dual antiplatelet therapy in coronary artery bypass graft

BACKGROUND

In most situations, many patients undergoing coronary artery bypass graft (CABG) are on dual antiplatelet therapy (DAPT), which is also required after CABG. The adjustment of antiplatelet strategy remains controversial. In this study, we systematically review current guidelines, seeking consensus and controversies to facilitate clinical practice.

METHODS AND RESULTS

Guidelines are searched in PubMed, Embase, ECRI Guidelines Trust and websites of guidelines organizations and professional society. Guidelines with recommendations of DAPT for patients undergo CABG are included. Two reviewers appraised guidelines with the Appraisal of Guidelines for Research and Evaluation II (AGREE II). Relevant recommendations are extracted and summarized. A total of 14 guidelines meeting inclusion criteria are selected, with average AGREE II scores from 44% to 86%. Most guidelines score high in domains other than 'applicability'. Many guidelines are not detailed enough in reporting considerations behind recommendations. Current guidelines are consistent on the management of antiplatelet strategy before elective CABG and using DAPT after surgery for preventing graft vessel occlusion. Evidence is still lacking in urgent CABG and resumption of the previous DAPT after surgery.

CONCLUSIONS

Current guidelines on DAPT in CABG are generally satisfying. Suspending P2Y12 inhibitors while aspirin continued before elective CABG is recommended, as well as 12 months of DAPT following CABG. More evidence is needed to guide antiplatelet therapy in urgent CABG and to prove the benefits of resuming previous DAPT.

Reoperation for bleeding following coronary artery bypass surgery with special focus on long-term outcomes

Objectives: We studied the incidence and risk factors of reoperation for bleeding following CABG in a nationwide cohort with focus on long-term complications and survival. Design: A retrospective study on 2060 consecutive, isolated CABG patients operated 2001-2016. Outcome of reoperated patients (n = 130) were compared to non-reoperated ones (n = 1930), including major adverse cardiac and cerebrovascular events (MACCE) and overall survival. Risk factors for reoperation were determined using multivariate logistic regression and a Cox proportional hazards model to assess prognostic factors of long-term survival. Median follow-up was 7.6 years. Results: One hundred thirty patients (6.3%) were reoperated with an annual decrease of 4.1% per year over the study period (p=.04). Major complications (18.5 vs. 9.6%) and 30-day mortality (8.5 vs. 1.9%,) were higher in the reoperation group (p<.001). The use of clopidogrel preoperatively (OR 3.62, 95% CI: 1.90-6.57) and reduced left ventricular ejection fraction (OR 2.23, 95% CI: 1.25-3.77) were the strongest predictors of reoperation, whereas off-pump surgery was associated with a lower reoperation risk (OR 0.44, 95% CI: 0.22-0.85). After exluding patients that died within 30 days postoperatively, no difference in long-term survival or freedom from MACCE was found between groups, and reoperation was not an independent risk factor for long-term mortality in multivariate analysis. Conclusions: The reoperation rate in this study was relatively high but decreased significantly over time. Reoperation was associated with twofold increased risk for major complications and fourfold 30-day mortality, but comparable long-term MACCE and survival rates. This implies that if patients survive the first 30 days following reoperation, their long-term outcome is comparable to non-reoperated patients.

When is the optimal time to discontinue clopidogrel before in-hospital coronary bypass surgery? A closer look at the current literature

BACKGROUND

Clopidogrel and other P2Y12 inhibitors have become the standard of care among patients presenting with acute coronary syndromes. A substantial proportion of these patients require surgical revascularization during index hospitalization.

HYPOTHESIS

Guidelines recommend a 5-day waiting period off clopidogrel before coronary artery bypass grafting (CABG) to reduce hemorrhagic complications. These recommendations are not routinely followed in clinical practice, while recent studies also propose shorter waiting periods off clopidogrel for patients awaiting in-hospital CABG.

METHODS

A preliminary PubMed search was conducted using the following MeSH terms under the publication type "Hemorrhage:" "Clopidogrel," AND "Coronary Artery Bypass." Relevant studies and guidelines were then reviewed and selected based on a predetermined criteria. Studies that formulated the current recommendations for stopping clopidogrel preoperative to CABG are discussed in detail this review.

RESULTS

A comprehensive review of recent evidence illustrates mixed bleeding and transfusion outcomes among CABG patients with preoperative exposure to clopidogrel in less than 5 days.

CONCLUSIONS

The optimal discontinuation time of clopidogrel before CABG is still poorly defined. The recommendation of a 5-day washout period for clopidogrel should be reconsidered to be on par with current clinical practice.

Dual antiplatelet therapy up to the time of non-elective coronary artery bypass grafting with prophylactic platelet transfusion: is it safe?

Background

Guidelines suggest that patients discontinue Clopidogrel at least 5 days prior to coronary artery bypass grafting (CABG). Those with acute coronary syndrome (ACS) are at high risk for myocardial infarction (MI) if not treated with dual antiplatelet therapy (DAPT). We sought to assess pre and post-operative outcomes of patients maintained on Clopidogrel and aspirin up to the time of surgery and compare them with those on aspirin alone.

Methods

From the cardiac surgery database, 240 patients were retrospectively registered between January and May 2017. There were 126 patients with ACS who underwent CABG on DAPT (Clopidogrel group [CG]) and 114 patients who underwent elective CABG on aspirin alone (control). The CG received intraoperative prophylactic platelet transfusion (PPT). Demographics, comorbidities, and laboratory data were prospectively entered at the time of surgery and were subsequently retrieved for analysis. Per and postoperative findings were identified and compared between both groups.

Results

The cohort consisted of 240 patients (mean age 61 years, 81.3% were male, SD ± 9.58). Patients in the CG were younger (Median 57 vs. 63, P-value 0.001), and with male predominance (86% versus 75%, P-value 0.028). In addition, they had less prevalence for diabetes and renal failure as compared to control (P-values 0.003, and 0.005, respectively). There were no significant differences between both groups in number of vessels grafts, duration of on-pump and aortic clamp. Hematologic laboratory data had also similar baseline values. The CG had similar bleeding rate, redo surgery and in-hospital death (P-values non-significant), however more infection and total hospital stay as compared to control (p-values 0.048 and 0.001).

Conclusion

Patients who are at increased risk for MI can be maintained on DAPT up to the time of CABG because surgery is safe when patients are offered PPT.

Effectiveness of adherence to a preoperative antiplatelet and anticoagulation cessation protocol in cardiac surgery

OBJECTIVES

Reduction of blood loss after cardiac surgery remains challenging. The effectiveness of adherence to a protocol on cessation of anticoagulants and platelet-inhibiting medications was investigated together with the influence of protocol violations on blood loss after surgery, use of blood products, surgical re-explorations and 30-day mortality.

METHODS

Between 2009 and 2013, data were collected prospectively for all elective cardiac surgery procedures in adult patients (n = 1637). Two groups were distinguished: Group 1 adhered to the protocol for cessation or continuation of medication (n = 1287, 79%) and Group 2 violated the protocol (n = 350, 21%).

RESULTS

Median blood loss was 300 ml (interquartile range 175-500 ml). Eighty patients underwent re-exploration due to blood loss (5%). Thirty-day mortality was 2% (n = 27). Protocol violation was associated with increased blood loss [median 275 ml (175-475 ml) vs 350 ml (250-612); P ≤ 0.001] and with increased average use of fresh frozen plasma (226 ml vs 139 ml; P  << 0.00001), red blood cell transfusion (115 ml vs 87 ml; P = 0.081) and thrombocyte transfusions (52 ml vs 37 ml; P = 0.0082). The number of re-explorations (4% vs 6%; P = 0.39) and mortality risk (1% vs 2%; P = 0.72) did not differ.

CONCLUSIONS

Balancing the benefit of continuing platelet inhibitors or anticoagulants versus cessation before surgery remains challenging. Adherence to the protocol will lead to lower blood loss and in a lower consumption of blood products although the decision to go for re-exploration and 30-day mortality does not differ compared with the protocol violation. Stopping medication does not lead to thromboembolic events.

American College of Veterinary Emergency and Critical Care (ACVECC) Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines: Small animal

OBJECTIVES

To systematically review available evidence and establish guidelines related to the risk of developing thrombosis and the management of small animals with antithrombotics.

DESIGN

Standardized, systematic evaluation of the literature (identified by searching Medline via PubMed and CAB abstracts) was carried out in 5 domains (Defining populations at risk; Defining rational therapeutic use; Defining evidence-based protocols; Refining and monitoring antithrombotic therapies; and Discontinuing antithrombotic therapies). Evidence evaluation was carried out using Population, Intervention, Comparison, Outcome generated within each domain questions to address specific aims. This was followed by categorization of relevant articles according to level of evidence and quality (Good, Fair, or Poor). Synthesis of these data led to the development of a series of statements. Consensus on the final guidelines was achieved via Delphi-style surveys. Draft recommendations were presented at 2 international veterinary conferences and made available for community assessment, review, and comment prior to final revisions and publication.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Over 500 studies were reviewed in detail. Worksheets from all 5 domains generated 59 statements with 83 guideline recommendations that were refined during 3 rounds of Delphi surveys. A high degree of consensus was reached across all guideline recommendations.

CONCLUSIONS

Overall, systematic evidence evaluations yielded more than 80 recommendations for the treatment of small animals with or at risk of developing thrombosis. Numerous significant knowledge gaps were highlighted by the evidence reviews undertaken, indicating the need for substantial additional research in this field.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 5-Discontinuation of anticoagulant therapy in small animals

OBJECTIVES

To systematically evaluate the evidence supporting the timing and mechanisms of permanent or temporary discontinuation of antiplatelet or anticoagulant medications in small animals DESIGN: Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality (poor, fair, or good), and development of consensus on conclusions via a Delphi-style survey for application of the concepts to clinical practice.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Databases searched included Medline via PubMed and CAB abstracts. Two specific courses of inquiry were pursued, one focused on appropriate approaches to use for small animal patients receiving antiplatelet or anticoagulant drugs and requiring temporary discontinuation of this therapy for the purposes of invasive procedures (eg, surgery), and the other aimed at decision-making for the complete discontinuation of anticoagulant medications. In addition, the most appropriate methodology for discontinuation of heparins was addressed.

CONCLUSIONS

To better define specific patient groups, a risk stratification characterization was developed. It is recommended to continue anticoagulant therapy through invasive procedures in patients at high risk for thrombosis that are receiving anticoagulant therapy, while consideration for discontinuation in patients with low to moderate risk of thrombosis is reasonable. In patients with thrombosis in whom the underlying cause for thrombosis has resolved, indefinite treatment with anticoagulant medication is not recommended. If the underlying cause is unknown or untreatable, anticoagulant medication should be continued indefinitely. Unfractionated heparin therapy should be slowly tapered rather than discontinued abruptly.

Perioperative Bridging With Glycoprotein IIb/IIIa Inhibitors Versus Cangrelor: Balancing Efficacy and Safety

OBJECTIVE

To review the efficacy and safety of perioperative administration of intravenous (IV) antiplatelet agents as a substitute for oral P2Y₁₂ inhibitors and to provide clinicians guidance on optimal and cost-effective use of these medications.

DATA SOURCES

A MEDLINE literature search (1950 to November 2018) was performed using the key search terms abciximab, bridging, cangrelor, cardiac surgery, coronary artery bypass surgery, eptifibatide, intravenous antiplatelet agent, and tirofiban. Additional references were identified from a review of literature citations.

STUDY SELECTION AND DATA EXTRACTION

In all, 18 original research reports and case reports/series were included in the review.

DATA SYNTHESIS

Prevention of postoperative bleeding is critical to decrease morbidity and mortality after cardiac surgery. IV antiplatelet medications have short half-lives and are frequently used to substitute for oral P2Y₁₂ inhibitors to allow platelet function recovery before procedures. Functional recovery of platelets is delayed after abciximab discontinuation and increases postoperative bleeding risk. Eptifibatide and tirofiban have similar pharmacokinetic/pharmacodynamic properties and comparable efficacy and safety in the setting of perioperative bridging. Cangrelor may be considered in patients with renal insufficiency as decreased clearance of eptifibatide or tirofiban may increase the risk of postoperative bleeding. Relevance to Patient Care and Clinical Practice: Comparative studies of IV antiplatelet medications have not been published. Appropriate use of IV antiplatelet medications can prevent perioperative ischemic events and bleeding.

CONCLUSIONS

Eptifibatide, tirofiban, and cangrelor are preferred over abciximab as a perioperative bridge. The choice of agent should be tailored to clinical characteristics of the patient and institutional acquisition costs.

Antithrombotic therapy management of adult and pediatric cardiac surgery patients

Despite the development of catheter-based interventions for ischemic and valvular heart disease, hundreds of thousands of people undergo open heart surgery annually for coronary artery bypass graft (CABG), valve replacement or cardiac assist device implantation. Cardiac surgery patients are unique because therapeutic anticoagulation is required during cardiopulmonary bypass. Developmental hemostasis and altered drug metabolism affect management in children. This narrative review summarizes the current evidence-based and consensus guidelines regarding perioperative, intraoperative and postoperative antithrombotic therapy in patients undergoing cardiac surgery. Anticoagulation preoperatively is required in the setting of cardiac arrhythmias, prior valve replacement or history of venous thromboembolism. In patients with ischemic heart disease, aspirin is continued in the perioperative period, whereas oral P2Y12 antagonists are withheld for 5-7 days to reduce the risk of perioperative bleeding. Intraoperative management of cardiopulmonary bypass in adults and children includes anticoagulation with unfractionated heparin. Variability in dose-response to heparin and influence of other medical conditions on dosing and reversal of heparin make intraoperative anticoagulation challenging. Vitamin K antagonist therapy is the standard anticoagulant after mechanical heart valve or left ventricular assist device (LVAD) implantation. Longer duration of dual antiplatelet therapy is recommended after CABG if patients undergo surgery because of acute coronary syndrome. Antiplatelet therapy after LVAD implantation includes aspirin, dipyridamole and/or clopidogrel in children and aspirin in adults. A coordinated approach between hematology, cardiology, anesthesiology, critical care and cardiothoracic surgery can assist to balance the risk of thrombosis and bleeding in patients undergoing cardiac surgery.

Management of antiplatelet therapy in patients undergoing elective invasive procedures. Proposals from the French Working Group on perioperative haemostasis (GIHP) and the French Study Group on thrombosis and haemostasis (GFHT). In collaboration with the French Society for Anaesthesia and Intensive Care Medicine (SFAR)

The French Working Group on Perioperative Haemostasis (GIHP) and the French Study Group on Haemostasis and Thrombosis (GFHT) in collaboration with the French Society for Anaesthesia and Intensive Care Medicine (SFAR) drafted up-to-date proposals for the management of antiplatelet therapy in patients undergoing elective invasive procedures. The proposals were discussed and validated by a vote; all proposals but one could be assigned with a high strength. The management of antiplatelet therapy is based on their indication and the procedure. The risk of bleeding related to the procedure can be divided into high, moderate and low categories depending on the possibility of performing the procedure in patients receiving antiplatelet agents (none, monotherapy and dual antiplatelet therapy respectively). If discontinuation of antiplatelet therapy is indicated before the procedure, a last intake of aspirin, clopidogrel, ticagrelor and prasugrel 3, 5, 5 and 7 days before surgery respectively is proposed. The thrombotic risk associated with discontinuation should be assessed according to each specific indication of antiplatelet therapy and is higher for patients receiving dual therapy for coronary artery disease (with further refinements based on a few well-accepted items) than for those receiving monotherapy for cardiovascular prevention, for secondary stroke prevention or for lower extremity arterial disease. These proposals also address the issue of the potential role of platelet functional tests and consider management of antiplatelet therapy for regional anaesthesia, including central neuraxial anaesthesia and peripheral nerve blocks, and for coronary artery surgery.

Assessing Intraoperative Bleeding Risk in Patients Undergoing Coronary Artery Bypass Grafting with Prior Exposure to Clopidogrel: Single Center Retrospective Analysis

In patients undergoing coronary artery bypass grafting (CABG), intraoperative and postoperative major bleeding requiring blood transfusions and surgical reexploration is associated with increased mortality and morbidity. Our study hypothesized that exposure to clopidogrel is not significantly associated with increased risk for intraoperative bleeding, even when administered less than 5 days before CABG. We also aimed to determine variables associated with intraoperative packed red blood cell (iPRBC) transfusion. Patients of both sexes aged 18 years or older who underwent CABG from July 1, 2011 to December 31, 2012 were included in the analysis. Study population consisted of 2 groups-clopidogrel arm and nonclopidogrel arm. Patients were included in clopidogrel arm if they were exposed to clopidogrel in the past (as one of their home medications or received the medication for first time during the index hospitalization), whereas patients who never received clopidogrel were included in nonclopidogrel arm. We identified a total of 303 adult patients who underwent CABG with a mean age was 64.5 years. Mortality rate in our study was 0.99% (n = 3) with increased mortality in women as compared with men (3.27% vs. 0.41%, P = 04). The mean iPRBC transfused were 1.68 units, with higher units being transfused in women as compared with men (2.23 vs. 1.49 units, respectively, P = 0.03) and no significant difference between clopidogrel and nonclopidogrel arms (1.92 vs. 1.50, respectively, P = 0.18). After multivariate analysis, age [odds ratio (OR) = 1.03, P = 0.01], female sex (OR = 2.61, P = 0.006) and hypertension (OR = 7.10, P = 0.02) predicted increased iPRBC transfusion. Clopidogrel or nonclopidogrel status was not associated with increased iPRBC transfusion (OR = 1.06, P = 0.81). iPRBC transfusion rates were similar in both arms with age, female sex, and hypertension being an independent predictor of iPRBC transfusion.

Should dual antiplatelet therapy be used in patients following coronary artery bypass surgery? A meta-analysis of randomized controlled trials

BACKGROUND

We assessed the effectiveness of dual antiplatelet therapy (DAPT) post elective or urgent (i.e., post acute coronary syndrome [ACS]) coronary artery bypass graft surgery (CABG).

METHODS

We systematically searched MEDLINE, EMBASE, and the Cochrane Registry from inception to August 2015. Randomized controlled trials (RCTs) in adults undergoing CABG comparing either dual vs. single antiplatelet therapy or higher- vs. lower-intensity DAPT were identified.

RESULTS

Nine RCTs (n = 4,887) with up to 1y follow-up were included. Five RCTs enrolled patients post-elective CABG (n = 986). Two multi-centre RCTs enrolled ACS patients who subsequently underwent CABG (n = 2,155). These 7 RCTs compared clopidogrel plus aspirin to aspirin alone. Two other multi-centre RCTs reported on ACS patients who subsequently underwent CABG comparing higher intensity DAPT with either ticagrelor (n = 1,261) or prasugrel (n = 485) plus aspirin to clopidogrel plus aspirin. Post-operative anti-platelet therapy was started when chest tube bleeding was no longer significant, typically within 24-48 h. There were no differences in all-cause mortality in clopidogrel plus aspirin vs. aspirin RCTs; conversely, all-cause mortality was significantly lower in ticagrelor and prasugrel vs. clopidogrel RCTs (risk ratio[RR] 0.49, 95% confidence interval[CI] 0.33-0.71, p = 0.0002; 2 RCTs, n = 1695; I(2)  = 0%; interaction p < 0.01 compared to clopidogrel plus aspirin vs aspirin RCTs). There were no differences in myocardial infarctions, strokes, or composite outcomes. Overall, major bleeding was not significantly increased (RR 1.31, 95% CI 0.81-2.10, p = 0.27; 7 RCTs, n = 4500). There was heterogeneity (I(2)   = 42%) due almost entirely to higher bleeding reported for the prasugrel RCT which included mainly CABG-related major bleeding (RR 3.15, 95% CI 1.45-6.87, p = 0.004; 1 RCT, n = 437).

CONCLUSIONS

Most RCT data for DAPT post CABG is derived from subgroups of ACS patients in DAPT RCTs requiring CABG who resume DAPT post-operatively. Limited RCT data with heterogeneous trial designs suggest that higher intensity (prasugrel or ticagrelor) but not lower intensity (clopidogrel) DAPT is associated with an approximate 50% lower mortality in ACS patients who underwent CABG based on post-randomization subsets from single RCTs. Large prospective RCTs evaluating the use of DAPT post-CABG are warranted to provide more definitive guidance for clinicians.

Preoperative platelet aggregation predicts perioperative blood loss and rethoracotomy for bleeding in patients receiving dual antiplatelet treatment prior to coronary surgery

INTRODUCTION

Patients scheduled for coronary artery bypass graft surgery (CABG) are commonly treated with clopidogrel. We sought to assess the relation between preoperative platelet aggregation and bleeds in CABG patients on clopidogrel.

MATERIAL AND METHODS

In a case-control study, we compared 52 consecutive patients undergoing isolated CABG on aspirin and clopidogrel 75mg/d versus 50 controls on aspirin monotherapy. Platelet aggregation induced by 10μmol/l adenosine di-phosphate (ADP) in platelet-rich plasma was measured in subjects on clopidogrel within 5days prior to surgery. ADP-induced aggregation of ≥50% was used to define subjects with satisfactory inhibition of platelet reactivity.

RESULTS

In 29 patients with preoperative ADP-induced aggregation ≥50%, compared with 23 subjects with aggregation <50%, lower chest-tube drainage volumes (after 6h, p=0.002; and 12h, p=0.001) and fewer rethoracotomies were observed (p=0.03). The former group was characterized with lower transfusion rates of packed red blood cells (p=0.009), platelet concentrate (p=0.04) and fresh frozen plasma (p=0.001). Patients with ADP-induced aggregation ≥50% did not differ from untreated controls regarding the postoperative drainage, transfusions and rethoracotomy. The incidence of thromboembolic events and death during perioperative period were similar in all groups. Multivariate logistic regression identified ADP-induced aggregation <50% as the only independent predictor of rethoracotomy (OR=2.94 [1.12-7.75], p=0.029).

CONCLUSIONS

Patients on aspirin and clopidogrel <5days before CABG who had preoperative ADP-induced platelet aggregation ≥50% have bleeding risk similar to those receiving aspirin monotherapy. Reduced platelet reactivity to ADP can predict postoperative bleeding in CABG patients on dual antiplatelet therapy.