Postoperative blood loss in patients undergoing coronary artery bypass surgery after preoperative treatment with clopidogrel. A prospective randomised controlled study
ABSTRACT The optimal timing for discontinuation of clopidogrel before surgery remains under debate. The purpose of this study is to determine the effect of preoperative clopidogrel administration on postoperative blood loss and the total requirements of homologous blood products after coronary artery bypass grafting (CABG). We also evaluated the perioperative complications.
Consecutive patients (n=130) undergoing elective CABG were recruited and randomised between 2006 and 2007. In 38 patients (group 1), treatment with clopidogrel was discontinued 5 days prior to surgery, in 40 patients (group 2) 3 days before surgery and in 40 other patients (group 3) clopidogrel was stopped on the day of surgery.
Significantly more postoperative blood loss was observed in group 3 compared to group 1 (929+/-472 ml vs 664+/-312 ml; p=0.009). Other group comparisons were not significant. Blood loss after 12 h and at drain removal was also significantly higher in group 3. Patients in group 3 also had higher total requirements of homologous blood products (p=0.046) and a significantly higher need for fresh frozen plasma (FFP) transfusion (p=0.034). Univariable regression analyses revealed that continuing clopidogrel till the day of surgery (group 3) was predictive for postoperative blood loss (beta=0.289; p=0.007) and the total requirements of homologous blood products after surgery (beta=0.280; p=0.008). These effects remained the same in multivariable analyses.
Continuation of clopidogrel until the day of surgery induces significantly more postoperative blood loss and increases significantly the total requirements of homologous blood products and FFP transfusion after surgery. The blood loss and the use of blood products in the group that stopped at 3 days preoperatively were similar to that of the group that stopped at 5 days preoperatively.
Conference Paper: On learning method in modelling and analysis of biocybernetic systems[Show abstract] [Hide abstract]
ABSTRACT: This paper reviews a learning process for the development of a model of a specific physiological control system. It provides an example of a nonlinear system structure, and elucidates processes of aggregating biological variables and of decomposing a system model at different time scales. A quasilinear approximate analysis of the model suggests an adaptive control mechanism which is yet to be explored.Decision and Control including the 13th Symposium on Adaptive Processes, 1974 IEEE Conference on; 01/1974
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ABSTRACT: Background Patients often fail to stop clopidogrel appropriately before non-cardiac surgery. Thromboelastography platelet mapping (TEG-PM) can be used to measure the percentage adenosine 5′-diphosphate platelet receptor inhibition (ADP-PRI) by clopidogrel in these patients.Methods This prospective case–control study investigated the risk of bleeding in patients who had taken clopidogrel within 7 days of scheduled operation. Patients underwent TEG-PM to stratify their bleeding risk. Low-risk (ADP-PRI below 30 per cent) and urgent priority high-risk (ADP-PRI 30 per cent or more) patients proceeded to surgery. The outcomes of these patients were compared with those of matched controls. Regression analysis, with bootstrapping validation, was used to identify independent risk factors for bleeding and an optimal cut-off value of ADP-PRI for cancellation of surgery.ResultsFrom May 2008 to October 2013, 182 patients failed to discontinue clopidogrel. No correlation was observed between duration of clopidogrel omission and percentage ADP-PRI; 112 low-risk and 19 high-risk patients proceeded to surgery. High-risk patients had significantly greater intraoperative packed red blood cell (PRBC) transfusion in comparison with their matched controls, and a strong positive correlation between percentage ADP-PRI and units of intraoperative PRBCs transfused (r = 0·749, 95 per cent confidence interval (c.i.) 0·410 to 0·940; P < 0·001). Percentage ADP-PRI was the only independent risk factor for intraoperative PRBC transfusion (odds ratio 1·07, 95 per cent c.i. 1·02 to 1·13; P = 0·005).Conclusion An objective measure of platelet inhibition with TEG-PM, using an ADP-PRI cut-off of 34 per cent, can be used to prevent unnecessary cancellations, while minimizing patient risk.British Journal of Surgery 07/2014; 101(11). DOI:10.1002/bjs.9592 · 5.21 Impact Factor
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ABSTRACT: Optimal perioperative antiplatelet therapy in patients with coronary stents undergoing surgery still remains poorly defined and a matter of debate among cardiologists, surgeons and anaesthesiologists. Surgery represents one of the most common reasons for premature antiplatelet therapy discontinuation, which is associated with a significant increase in mortality and major adverse cardiac events, in particular stent thrombosis. Clinical practice guidelines provide little support with regard to managing antiplatelet therapy in the perioperative phase in the case of patients with non-deferrable surgical interventions and/or high haemorrhagic risk. Moreover, a standard definition of ischaemic and haemorrhagic risk has never been determined. Finally, recommendations shared by cardiologists, surgeons and anaesthesiologists are lacking. The present consensus document provides practical recommendations on the perioperative management of antiplatelet therapy in patients with coronary stents undergoing surgery. Cardiologists, surgeons and anaesthesiologists have contributed equally to its creation. On the basis of clinical and angiographic data, the individual thrombotic risk has been defined. All surgical interventions have been classified according to their inherent haemorrhagic risk. A consensus on the optimal antiplatelet regimen in the perioperative phase has been reached on the basis of the ischaemic and haemorrhagic risk. Aspirin should be continued perioperatively in the majority of surgical operations, whereas dual antiplatelet therapy should not be withdrawn for surgery in the case of low bleeding risk. In selected patients at high risk for both bleeding and ischaemic events, when oral antiplatelet therapy withdrawal is required, perioperative treatment with short-acting intravenous glycoprotein IIb/IIIa inhibitors (tirofiban or eptifibatide) should be taken into consideration.EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology 05/2014; 10(1):38-46. DOI:10.4244/EIJV10I1A8 · 3.76 Impact Factor