Combined clopidogrel and aspirin treatment up to surgery increases the risk of postoperative myocardial infarction, blood loss and reoperation for bleeding in patients undergoing coronary artery bypass grafting.

OBJECTIVES: Recent guidelines suggest that patients undergoing coronary artery bypass grafting (CABG) should discontinue clopidogrel and aspirin (ASA) 5 and 2-10 days, respectively, before surgery to reduce postoperative bleeding and its complications. The aim of our study was to evaluate the relationship between the timing of discontinuing clopidogrel + ASA and early clinical outcomes in patients undergoing CABG. METHODS: Four thousand three hundred and thirty consecutive patients underwent isolated CABG from April 2004 to February 2009. Of these, 926 patients received double antiplatelet therapy in the 14 days prior to surgery. Patients were stratified into three groups: clopidogrel + ASA within 5 and 2 days, respectively, before surgery (Group A, n = 287); clopidogrel within 5 days + ASA stopped 2-10 days before surgery or clopidogrel stopped 5 days + ASA within 2 days of surgery (Group B, n = 308) and clopidogrel + ASA discontinued >5 and 10 days, respectively, before surgery (control group, n = 331). RESULTS: Overall mortality was 0.8%. The incidence of postoperative myocardial infarction (MI) was 5.2, 1 and 1.8% in Groups A, B and control, respectively (P = 0.004). Reoperation for bleeding occurred in 4.5, 2.9 and 1.2% (P = 0.04) and total chest drainage was 761 ± 473, 720 ± 421 and 687 ± 302 ml in Groups A, B and control, respectively (P = 0.06). Multivariable analysis revealed that Group A was an independent predictor of postoperative MI (P = 0.02), reoperation for bleeding (P = 0.02), blood transfusions (P = 0.003) and blood losses (P = 0.015). CONCLUSIONS: Clopidogrel in combination with ASA up to the time of surgery is associated with an increased risk of postoperative MI, blood loss and reoperation for bleeding in patients undergoing CABG.

Mild renal dysfunction in patients undergoing cardiac surgery as a new risk factor for EuroSCORE.

BACKGROUND: It has recently been suggested that mild renal dysfunction is associated with increased mortality in cardiac surgery; however, this risk factor is not accounted for in the European System for Cardiac Operative Risk Evaluation (EuroSCORE). The aim of the present study was to assess the effect of mild renal dysfunction as a predictor of operative mortality and develop and validate a modified logistic EuroSCORE model. METHODS: This was a retrospective, observational, cohort study of prospectively collected data on 16 086 consecutive patients undergoing cardiac surgery at the Bristol Heart Institute between April 1996 and February 2009. To develop a modified logistic EuroSCORE, data were dived into developmental and validation datasets (11 596 and 4490 patients respectively). The relationship between risk factors and mortality was assessed using univariate and logistic regression analysis. Calibration and discrimination were assessed by Hosmer Lemeshow χ(2) test and receiving operative characteristic (ROC) curve. RESULTS: Overall hospital mortality was 2.6%. At multivariate analysis, 13 out of 18 variables of the EuroSCORE influenced operative mortality; moreover, preoperative mild renal dysfunction, defined as serum creatinine 130-199 µmol/l, was identified as a new risk factor for mortality (OR 1.819, 95% CI 1.353 to 2.447, p<0.0001). EuroSCORE was able to predict mortality; however, modified logistic EuroSCORE had a better discriminatory power (area under ROC: 0.844 vs 0.784, p=0.002). CONCLUSIONS: Preoperative mild renal dysfunction is an independent risk factor for mortality in patients undergoing cardiac surgery. These findings now need to be validated with data from other centres.

A clinical score to predict the need for intraaortic balloon pump in patients undergoing coronary artery bypass grafting.

BACKGROUND: There is no accepted consensus on the definition of high-risk patients who may benefit from the use of intraaortic balloon pump (IABP) in coronary artery bypass grafting (CABG). The aim of this study was to develop a risk model to identify high-risk patients and predict the need for IABP insertion during CABG. METHODS: From April 1996 to December 2006, 8,872 consecutive patients underwent isolated CABG; of these 182 patients (2.1%) received intraoperative or postoperative IABP. The scoring risk model was developed in 4,575 patients (derivation dataset) and validated on the remaining patients (validation dataset). Predictive accuracy was evaluated by the area under the receiver operating characteristic curve. RESULTS: Mortality was 1% in the entire cohort and 18.7% (22 patients) in the group which received IABP. Multivariable analysis showed that age greater than 70 years, moderate and poor left ventricular dysfunction, previous cardiac surgery, emergency operation, left main disease, Canadian Cardiovascular Society 3-4 class, and recent myocardial infarction were independent risk factors for the need of IABP insertion. Three risk groups were identified. The observed probability of receiving IABP and mortality in the validation dataset was 36.4% and 10% in the high-risk group (score >14), 10.9% and 2.8% in the medium-risk group (score 7 to 13), and 1.7% and 0.7% in the low-risk group (score 0 to 6). CONCLUSIONS: This simple clinical risk model based on preoperative clinical data can be used to identify high-risk patients who may benefit from elective insertion of IABP during CABG.