Background and Goal of Study: 
In patients undergoing cardiac surgery, the withdrawal of antithrombotic agents may prevent bleeding preoperatively, but may also increase the risk of cardiac complications. In a meta-analysis involving six studies, a three-fold increase in the incidence of major cardiac side-effects was observed in patients who quit daily aspirin therapy (1). Our aim in this retrospective cohort study is to determine the incidence of thrombotic complications that may be associated with discontinuation of preoperative anticoagulants in patients undergoing open heart surgery. We also evaluated the possible association with significant bleeding risk in patients with ongoing medication.

Materials and Methods: Following the Ethics Committee approval, the data of 512 adult patients undergoing elective open hearth surgery with cardiopulmonary bypass between 2013 and 2016 were evaluated. Patients treated with dual antiplatelet therapy were included. Clopidogrel and new generation of oral direct anticoagulants were discontinued at least 5 days and prasugrel at least 7 days before surgery according to the American College of Cardiology/American Heart Association guidelines (2)
Patients were divided into two groups. Group 1 patients (n=255) have suspended their aspirin therapy prior to surgery. Group 2 patients (n=257) have not suspended their aspirin therapy. Heart transplantation, left ventricular assist device implantation and repair of congenital heart malformations were excluded. Demographics, cardiac reserves, preoperative and postoperative Htc levels, the types of anticoagulants, the transfusion of blood products, possible complications and mortality rates were recorded.

Results and Discussion:
The demographics, the duration of surgery, hospital and ICU stay, CPB time, mortality rate, reexploration rate, the need for RBC, cryopresipitate or FFP did not differ between groups (p>0.05, Table 1,2). The amount of platelet suspension in the antithrombotic group was significantly higher than in the group without antithrombotic agent (p ˂ 0.05).

Conclusion(s): Neither reexploration nor transfusion rates were different for cardiac patients on aspirin therapy. Therefore, aspirin didnot increase the incidence of postoperative complications even for cardiac surgery, where heparinization and extra corporeal circulation are necessary. In conclusion, we are in the opinion that aspirin hasnot a negative effect on patient outcomes and should not be discontinued in patients undergoing major surgery.
 
References (optional): 
1. Biondi-Zoccai G, Lotrionte M, Agostoni P, et al. A systematic review and meta-analysis on the hazards of discontinuing or not adhering to aspirin among 50 279 patients at risk for coronary artery disease. Eur Heart J. 2006;27:2667–74.
2. Wright RS, Anderson JL, Adams CD, et al. 2011 ACCF/AHA focused update of the guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation 2011;123:2022–60


02 / Effects of withdrawal of antithrombotic agents on the risk of thrombosis and bleeding in patients undergoing cardiac surgery