Date Published: July 17, 2017
Publisher: Public Library of Science
Author(s): Jiwon Lee, Chul-Woo Jung, Yunseok Jeon, Tae Kyong Kim, Youn Joung Cho, Chang-Hoon Koo, Yoon Hyeong Choi, Ki-Bong Kim, Ho Young Hwang, Hang-Rae Kim, Ji-Young Park, Giacomo Frati.
The benefit of aspirin use after coronary artery bypass graft surgery has been well proven. However, the effect of preoperative aspirin use in patients undergoing off-pump coronary artery bypass graft surgery (OPCAB) has not been evaluated sufficiently. To evaluate platelet function changes during OPCAB due to preoperative aspirin use, we conducted a randomized controlled trial using flow cytometry and the Multiplate® analyzer. Forty-eight patients scheduled for elective OPCAB were randomized to the aspirin continuation (100 mg/day until operative day) and discontinuation (4 days before the operative day) groups. Platelet function was measured using the platelet activation markers CD62P, CD63, and PAC-1 by flow cytometry, and platelet aggregation was measured using the Multiplate® analyzer, after the induction of anesthesia (baseline), at the end of the operation, and 24 and 48 h postoperatively. Findings of conventional coagulation assays, thromboelastography by ROTEM® assays, and postoperative bleeding—related clinical outcomes were compared between groups. No significant change in CD62P, CD63, or PAC-1 was observed at the end of the operation or 24 or 48 h postoperatively compared with baseline in either group. The area under the curve for arachidonic acid—stimulated platelet aggregation, measured by the Multiplate® analyzer, was significantly smaller in the aspirin continuation group (P < 0.01). However, chest tube drainage and intraoperative and postoperative transfusion requirements did not differ between groups. Our study showed that preoperative use of aspirin for OPCAB did not affect perioperative platelet activation, but it impaired platelet aggregation, which did not affect postoperative bleeding, by arachidonic acid.
The use of aspirin after coronary artery bypass graft surgery (CABG) has been proven consistently to be beneficial since the Mangano study [1–4]. However, preoperative use of aspirin has not shown a consistent clinical benefit in patients undergoing CABG [5–7]. Most previous studies of the effect of preoperative aspirin use in this patient population have been retrospective [2–4, 6]. A large randomized clinical trial was conducted recently to examine this issue, but it did not involve the evaluation of platelet function, and aspirin use was randomized on the day of surgery . Moreover, most enrolled patients underwent on-pump CABG. Considering the strong effect of cardiopulmonary bypass (CPB) on the coagulation system, the effect of aspirin use may differ between on-pump CABG and off-pump coronary artery bypass graft surgery (OPCAB).
This prospective, randomized, double-blinded, clinical trial was approved by the institutional review board of Seoul National University Hospital, Seoul, Korea (1310-046-526). The study protocol was registered at clinicaltrials.gov (NCT 02209909). Patients were enrolled, after providing written informed consent, between May 2014 and August 2015.
Between May 2014 and August 2015, 160 patients received elective OPCAB and 112 patients were excluded from this study. Forty-eight patients were randomized and included in the final analyses (Fig 1). Preoperative patient characteristics and variables related to anesthesia and surgery did not differ between groups (Tables 1 and 2).
In this study of 48 patients undergoing OPCAB, platelet activation measured by increment of CD62P, CD63, and PAC-1 did not differ between the aspirin continuation and discontinuation groups until postoperative day 2. The AUC obtained by the ASPI test was significantly lower in the aspirin continuation group than in the aspirin discontinuation group during the perioperative period. However, chest tube drainage and perioperative transfusion requirements were similar in the two groups.