Antiplatelet Therapy For Patients Undergoing Coronary Artery Bypass Surgery

Coronary artery disease(CAD),or coronary heart disease is one of the most common cardiovascular diseases.The prevalence of unhealthy lifestyle and risk factors have led to a younger and more complex coronary artery disease population.Coronary artery bypass grafting(CABG)is the most complete and durable treatment for CAD,especially for those with extensive coronary artery disease or diabetes.The expanded lifespan of the whole population has raised new standard for the outcomes of patients had CABG,and strategies designed to minimize perioperative complications and prevent long-term adverse cardiovascular events are of vital importance to help patients obtain the highest level of physical health and quality of life after CABG.The benefits of dual antiplatelet therapy(DAPT)for preventing recurrent ischemic events and death in patients with acute coronary syndrome(ACS)have been well established.For the estimated 10%-15%of patients hospitalized with ACS who requiring CABG during their stay,the competing risks of thrombotic events as a result of interrupted antiplatelet therapy and surgery-related bleeding complications of continued antiplatelet therapy have put patients in a thorny dilemma concerning the timing of surgery and optimal preoperative antithrombotic management.Besides,current clinical practice guidelines recommended that DAPT be continued for these patients after CABG,merely based on expert consensus or underpowered secondary data.Furthermore,as patients who have undergone CABG still at risk for subsequent ischemic events as a result of aspirin resistance,native coronary artery disease progression and vein graft failure,whether this strategy can be used for the whole CABG population remains insufficiently investigated,there is even less evidence available on the efficacy and safety of DAPT in specific patient populations.The principle of this study was to provide high-quality evidence for the optimal management of DAPT in CABG population.Firstly,the study investigated the associations between continuous clopidogrel therapy within 5 days before CABG and major adverse cardiac and cerebrovascular events and bleeding complications in ACS patients presenting for CABG.Secondly,the study examined the associations between post-CABG DAPT with clopidogrel plus aspirin and clinical outcomes.Finally,we reviewed the latest data and evidence to date on strategies and concepts that may provide deeper insights in the field of antiplatelet therapy as secondary prevention for CABG patients.Main findings of the studies are listed as follows.Chapter 1 Preoperative Clopidogrel and Outcomes in Patients with Acute Coronary Syndrome Undergoing Coronary Artery Bypass SurgeryObjectiveThe optimal preoperative antiplatelet strategy for patients with acute coronary syndrome(ACS)requiring surgical revascularization remains unclear because of competing risks of bleeding and ischemic events.We evaluated the association between clopidogrel within 5 days before coronary artery bypass grafting(CABG)and outcomes in ACS patients.MethodsConsecutive patients with ACS who underwent isolated CABG at a single center were included in this retrospective study.The primary outcome was a composite of death,myocardial infarction and stroke within 30 days after surgery.Secondary outcomes were CABG-related major bleeding and perioperative transfusion.Inverse probability weighting using propensity score was performed to evaluate the risk-adjusted association of preoperative clopidogrel on outcomes.ResultsOf 5543 ACS patients,820(14.8%)patients continued clopidogrel within 5 days before CABG.After adjustment for differences in baseline factors,clopidogrel use?5 days before CABG was associated with significantly increased odds of the primary composite outcome(4.3%vs 2.0%;odds ratio[OR],1.63;95%confidence interval[CI],1.16-2.29;P=0.005),stroke(2.0%vs 0.6%;OR,3.13;95%CI,1.82-5.39;P<0.001),major bleeding(OR,2.01;95%CI,1.56-2.58;P<0.001),and transfusion(OR,2.05;95%CI,1.82-2.30;P<0.001)as compared with those who stopped clopidogrel>5 days before surgery.There were clear trends in decreasing event rates with increasing numbers of clopidogrel discontinuation days.Patients who received clopidogrel within 3-5 days before surgery had higher rates of primary composite outcome,major bleeding,and transfusion than those who stopped clopidogrel for>5 days.ConclusionsAmong patients with ACS undergoing CABG,clopidogrel therapy within 5 days before surgery was associated with increased odds of major adverse cardiac and cerebrovascular events and bleeding complications than discontinuing clopidogrel for>5 days.Chapter 2 Dual Antiplatelet Therapy with Clopidogrel and Aspirin Versus Aspirin Monotherapy in Patients Undergoing Coronary Artery Bypass SurgeryObjectiveWe evaluated the association of dual antiplatelet therapy(DAPT)with clopidogrel plus aspirin and clinical outcomes among patients undergoing CABG.MethodsThis retrospective cohort study using data from a contemporary registry included consecutive patients who underwent primary isolated CABG between 2013 and 2017.DAPT treatment was determined by claimed prescriptions after surgery.The primary outcome was a composite of all-cause death,myocardial infarction,stroke,or repeat revascularization within 6 months after CABG.Secondary outcomes were major bleeding and the individual components of the primary outcome.Cox regression models with inverse probability of treatment weighting(IPT W)were used to examine the associations between DAPT and outcomes while reducing treatment-selection bias.ResultsAmong 18069 patients with CABG,10854(60.1%)received DAPT with clopidogrel plus aspirin after surgery.Patients who received DAPT,compared with those who received aspirin monotherapy,had a lower incidence of the primary composite outcome at 6 months(2.9%vs 4.2%;IPTW-adjusted hazard ratio[HR],0.65;95%confidence interval[CI],0.55-0.77;P<0.001)as well as death(0.6%vs 0.9%;HR,0.61;95%CI,0.41-0.90;P=0.012),myocardial infarction,and stroke.The incidence of major bleeding did not differ significantly between the two groups(0.5%vs 0.4%;HR,1.11;95%CI,0.69-1.78;P=0.67).Similar results were noted across multiple subgroups defined by acute coronary syndrome or stable angina,diabetes status,and on-or off-pump CABG as well as when using different analytic methods.ConclusionsAmong patients undergoing CABG,DAPT with clopidogrel plus aspirin as secondary prevention was associated with reduced risk of major adverse cardiovascular and cerebrovascular events within 6 months as compared with aspirin monotherapy,and there was no significant increase in major bleeding.