Objectives Outcome in patients with acute coronary syndrome (ACS) is improved with dual antiplatelet therapy (DAPT). Patients with acute aortic dissection type A (AAD) often present with similar symptoms and may therefore be prescribed DAPT before diagnosis. The aim of this study was to evaluate the use of antiplatelet therapy (APT) prior to AAD surgery and patient outcome, including indications according to the European Society of Cardiology's (ESC) recent guidelines. Design A retrospective, observational study. Setting A tertiary University Hospital, Rigshospitalet, Heart Centre, Copenhagen, Denmark. Participants The study included 171 patients operated for AAD during 2010 to 2014. Interventions The independent relationship of preoperative APT was explored on 30-day mortality, intraoperative bleeding and perioperative transfusion requirements. Furthermore, the indications for APT were obtained. Measurements and Main Results Patients receiving APT (n = 73) did not have an increased 30-day mortality (29% v 20%, p = 0.18). However, APT increased intraoperative bleeding by 45% (p<0.001) and increased perioperative transfusion of red blood cells by 71%, fresh frozen plasma by 52%, and platelets by 56% (p = 0.002). Among patients receiving APT preoperatively, 26 patients received acetylsalicylic acid (ASA) alone and 46 patients received DAPT. Bleeding was significantly more pronounced in patients receiving DAPT (5.6±4.1 L), compared to ASA alone (3.6±3.1 L) and no APT (3.3±4.8 L) (p<0.001). However, there was no significant difference in mortality between groups. DAPT, including ticagrelor, increased intraoperative bleeding by 62% compared to DAPT with clopidogrel (p = 0.004). Among patients receiving DAPT, only 30% of the patients fulfilled ESC criteria for ACS treatment. Conclusions The use of APT was associated with increased intraoperative bleeding and transfusion requirement; however, it was not associated with a statistically significant increased mortality. Only a minority of patients fulfilled ESC criteria for ACS treatment with DAPT.