Abstract 31: Center-specific Variation in Use of Dual Antiplatelet Therapy Prior to Coronary Surgery: an Outcomes Analysis from the Maryland Cardiac Surgery Quality Initiative

Abstract

Background: Understanding institutional practices and associated outcomes of patients managed with different dual antiplatelet therapy (DAPT) strategies prior to coronary artery bypass grafting (CABG) could inform practice improvement. We hypothesized that, while receipt of DAPT within 5 days prior to CABG would increase risk for postoperative bleeding, there is institutional variation in preoperative DAPT management. Methods: A retrospective cohort study was performed using data from the Maryland Cardiac Surgery Quality Initiative (MCSQI), a consortium aggregating data from the 10 hospitals that perform cardiac surgery in Maryland. Isolated CABG patients between 2011 and 2018 were included. The exposure variable of interest was DAPT use within 5 days prior to CABG. The temporal trend in preoperative use of DAPT, heterogeneity in DAPT usage between centers, and perioperative outcomes are reported. The primary outcomes were the STS major morbidity/mortality composite measure and postoperative bleeding events. Results: The sample included 13,965 patients, of which 23% ( n =3,219) received preoperative DAPT within 5 days of surgery. The percentage of CABG patients treated with DAPT within 5 days decreased over time from 26% in 2011 to 15% in 2018 (Figure, P <0.001 for trend). There was significant heterogeneity in preoperative DAPT use among centers within the state (Figure, P <0.001 for difference in proportions). CABG patients receiving preoperative DAPT were more likely to present with acute MI (49% v 27%, P <0.001) and less likely to present electively (19% v 34%, P <0.001). The ratio of observed-to-expected STS-defined morbidity/mortality was similar between DAPT (O/E 0.85, 95% CI 0.77-0.92) and non-DAPT groups (O/E 0.84, 95% CI 0.79-0.89). Median transfusion of blood products was higher for the DAPT group (1 [0-4] v 0 [0-3], P <0.001). In adjusted models, preoperative DAPT was associated with greater odds of reoperation for bleeding (OR=1.38, P =0.017) and transfusion of ≥2 PRBC units (OR=1.27, P <0.001). Conclusion: Many isolated CABG patients in the state of Maryland are treated with DAPT within 5 days prior to CABG with notable variation between centers. Given the associated risk of postoperative bleeding, standardized management of preoperative DAPT therapy could improve post-CABG outcomes.