Early dual antiplatelet therapy versus aspirin monotherapy after coronary artery bypass surgery: survival and safety outcomes.

BACKGROUND: There is currently conflicting evidence regarding outcomes of dual antiplatelet therapy (DAPT) in patients following coronary artery bypass grafting (CABG). We aim to compare the survival and safety outcomes of DAPT versus aspirin (ASA) within a 24h window after CABG. METHODS: Single-centre retrospective cohort study on consecutive patients undergoing 1st isolated CABG surgery in 2010. Survival analysis (median follow-up 9 years) was performed using Kaplan-Meier curves and multivariable Cox regression using propensity score (PS) as a covariate along with DAPT. Bleeding was assessed through red blood cells' (RBC) transfusion, re-exploration of thorax and drainage. RESULTS: We included 351 patients (251 were DAPT). Kaplan-Meier curves showed similar cumulative survival between groups (9y: 75% DAPT vs. 67% ASA, Log-rank p=0.103), as well as the PS adjusted analysis (HR DAPT: 0.93, 95%CI:0.57-1.51). We found no differences in early mortality (2 DAPT and 1 ASA). Total median cell-saver transfusion (300mL vs. 250mL) and the re-exploration of thorax due to bleeding (1.6% vs. 4%) showed no statistical significance either. On the other hand, post-operative total median chest tube drainage was higher in the ASA group (1220mL DAPT vs. 1320mL ASA, p=0.034). There was also a lower frequency of DAPT patients requiring RBC transfusions (≥3 units 4.8% vs. 13%, p=0.009, respectively). Redo-CABG was performed in 3 patients (2 DAPT vs. 1 ASA) during follow-up. CONCLUSIONS: Compared with ASA, DAPT showed a non-significant impact on long- term survival and demonstrated to be a safe option. Further studies are needed to provide recommendations on the therapeutical strategy following CABG.