Our center performs around one thousands open heart surgeries per year and is one of the most active centers in the region. Our data shows that cardiovascular surgery with sustained Clopidogrel is feasible and the increasing experience of the cardiovascular team makes it safe. However, past research showed conflicting results. In a prospective observational study Ouattara et al.  compared the perioperative bleeding rate in patients who underwent first time CABG on aspirin alone with those on Aspirin and Clopidogrel 5 days prior to surgery while receiving prophylactic low dose Aprotinin (a fibrinolysis inhibitor). There were no differences in the perioperative bleeding rate or transfusions requirements between both groups. In another randomized double blind placebo-controlled study , 136 patients with ST-segment elevation myocardial infarction (STEMI) requiring CABG during the same hospitalization were assigned to either CG or placebo at the time of fibrinolysis therapy. There was no significant difference in perioperative bleeding rate, with a reduction of 30 days incidence of adverse ischemic events among the CG. Indeed, in a large prospective randomized trial, Ebrahimi et al.  showed that administration of Clopidogrel in non STEMI requiring CABG was associated with fewer adverse ischemic events and non-significant increased post-operative bleeding compared to patients who did not receive Clopidogrel. However, a 5-day washout period prior to surgery was considered in all patients in the CG.
On the other hand, a meta-analysis of 34 studies including 22,584 patients  showed increased mortality and post-operative bleeding among Clopidogrel-exposed patients who underwent CABG; nevertheless, authors recommended that high-risk ACS patients should proceed with CABG without delay for a Copidogrel-free period. Another meta-analysis  of 6,385 ACS patients who required CABG showed that exposure to Clopidogrel within 5 days prior to CABG was associated with increased major bleeding and reoperation, although it showed significantly lower incidence of mortality and ischemic adverse events. The authors suggested that ACS patients, who were subsequently referred for CABG, should wait for a minimum of 5 days washout period to prevent bleeding and reoperation. Another study conducted by Nurozler et al.  showed increased bleeding rate and re-exploration for bleeding in patients exposed to Clopidogrel within a week of CABG. The duration of mechanical ventilation and length of stay were also longer compared to control group among those patients. Miceli et al.  showed that Clopidogrel within 5 days in combination with aspirin within 2 days of CABG was associated with an increased risk of postoperative myocardial infarction, bleeding and reoperation for bleeding. Likewise, other retrospective case control studies showed that patients who underwent CABG shortly after Clopidogrel exposure had increased risk of re-exploration for bleeding [14,15,16], and bleeding risk was significantly higher when Aspirin and Clopidogrel were continued up to 2 days prior to surgery .
Bleeding in cardiac surgery is whether surgically induced or due to acquired hemostatic defect. Platelet dysfunction due to antiplatelet therapy prior to CABG is the most important hemostatic factor that may lead to bleeding [5, 17]. According to the American Heart Association/American College of Cardiology Foundation, ACS patients on dual antiplatelet therapy (DAPT) requiring non-elective CABG are considered to be at high risk for bleeding . Recommendations provided by the American and European guidelines regarding prophylactic preprocedural platelet transfusion remain conflictual [19,20,21] and data regarding PPT in cardiac surgery on DAPT is still a matter of debate. In the absence of clear and questionable recommendations regarding this specific high-risk population, our results show the safety of operating on DAPT. Platelets transfusions should be viewed as scarce resource that has benefits and risks. Previously published data regarding this issue showed conflicting results. In an observational case control study , patients who proceeded with CABG (intervention group) and received isolated one pool of platelet transfusion early after discontinuation of the pump while in the operating room were compared to those who did not receive platelets. It showed no difference in reexploration, infection, organ failure and ischemic adverse events between groups. However, the intervention group had less chest tube drainage but experienced prolonged ICU stay, mechanical ventilation, need of inotropic medications and blood products transfusion requirement. In a retrospective cohort study, Karkouty et al.  showed that platelet transfusion in patients undergoing cardiac surgery was not associated with increased mortality and morbidity. In contrast, in a retrospective analysis of a double-blind placebo versus control study, Spiess et al.  showed that platelet transfusion in patients undergoing CABG was associated with increased serious adverse events, like infection, longer hospital stay, requirement of packed red blood cells transfusions, stroke and death compared to those who did not receive platelet transfusion.
Our study showed that prophylactic platelet transfusion in ACS patients requiring CABG while on DAPT up to less than 5 days prior to surgery is safe. There was no difference in the 3 co-primary and secondary endpoints between both groups. Moreover, chest tube drainage per 24 h in the CG and control group were similar (220 vs. 240 ml, P-value 0.476), and, compared to what was previously published, the amount was much smaller [1,2,3, 6,7,8,9, 11,12,13,14]. This finding was felt to be, though not truly confirmed, secondary to the surgical expertise and the protective effect of the peroperative prophylactic platelet transfusion.
Strengths and limitations
The timing of Clopidogrel discontinuation was precisely registered, and was less than 5 days prior to surgery, which might have prevented the adverse ischemic events. The amount of pre, intra, and post-operative blood product transfusions were analyzed. All patients were operated by the same surgical team and followed the same blood product transfusion protocol.
Despite those strengths, we recognize four limitations. First, this is a single center, retrospective, observational study. The sample size is relatively small given the short period of data collection. Second, no preoperative antiplatelet activity was done before PPT, because of non availability. Third, we did not compare the outcome to a true placebo group naïve to Clopidogrel and Aspirine, since in our routine practice we perform most of our surgeries without discontinuing Aspirine, nevertheless this might be an additive criterion for the feasibility and safety of open heart surgery without discontinuing any anti-platelet therapy. It would be of major interest to design a prospective study comparing ACS patients operated without delay and without discontinuing dual anti platelet therapy, while receiving platelet transfusion to ACS ptients operated with 5 to 7 days delay after discontinuing dual anti platelet therapy.