Canadian Journal of Anesthesia/Journal canadien d anesthésie | 2021
Tranexamic acid for primary elective off-pump coronary artery bypass grafting surgery
Abstract
To the Editor, Hemorrhagic complications and transfusion-related morbidities complicate coronary artery bypass grafting surgery (CABG). Tranexamic acid (TXA) is an antifibrinolytic medication that reduces fibrin clot degradation by inhibiting plasminogen activators. Tranexamic acid use is associated with a reduction in bleeding and transfusion in on-pump CABG. Nevertheless, the evidence for TXA use in the off-pump CABG (OPCAB) setting is less robust. In a frequently cited report examining TXA use in CABG surgery, only 142 of 4,631 patients underwent off-pump surgery. Evidence from previous randomized controlled trials (RCTs) evaluating TXA use in OPCAB surgery suggests its efficacy and safety. Nevertheless, small sample sizes and, therefore, limited statistical power are commonly cited limitations of these studies. Our institution performs a considerably high volume of OPCAB procedures. As such, we conducted a single-centre historical chart review to assess the efficacy and usage patterns of TXA in OPCAB surgery. The hospital research ethics board approved this study in April 2018. Using the prospectively collected Cardiac Anesthesia Perioperative database, we identified 348 adult patients who underwent primary elective OPCAB surgery using median sternotomy from 1 April 2017 to 28 August 2018. Emergency cases, redo-sternotomy, conversion to on-pump, and minimally invasive cases were excluded. The exposure studied was any perioperative TXA administration. Our primary outcome was chest tube drainage at 12 hr postoperatively; secondary outcomes included mean TXA dose (g), chest tube drainage at 3 hr, 6 hr, and 24 hr postoperatively, chest tube duration (hr), 24 hr blood product transfusion (mL), and intensive care unit (ICU) and hospital length of stay (days). Data were analyzed using IBM SPSS Statistics, version 27.0 (IBM Corp., Armonk, NY, USA). Paired t tests were performed to compare continuous data. Categorical data were compared using the Chi square test. One hundred seventy-six patients received TXA and 172 patients did not. The mean (standard deviation) dose of TXA was 2.1 (1.5) g. Postoperative chest tube drainage was significantly reduced in patients receiving TXA at 12 hr, 3 hr, 6 hr, and 24 hr compared with the non-TXA group. There were no statistically significant differences in chest tube duration, transfusion amount, or ICU/hospital lengths of stay (Table). Consistent with previous literature, our study found TXA use to be associated with a significant reduction in postoperative blood loss at all time intervals in OPCAB surgery. Chest tube duration and ICU and hospital lengths of stay did not differ significantly between groups. Notably, the difference in allogenic blood product transfusion was not significant between groups. Relatively lower OPCAB case volumes likely stunted sample sizes in previous studies. In a meta-analysis of eight RCTs, the largest individual study comprised 100 patients. Our study addresses some of the deficits of previous literature. With a sample size of 348 patients, we performed a reasonably large single-institution study showing the efficacy of TXA for ameliorating bleeding in OPCAB surgery. Of note, the prevalence of prior myocardial infarction was higher in the B. R. Weingarten D. T. T. Tran, MD, FRCPC, MSc R. Mahaffey, MD, FRCPC B. Sohmer, MD, MEd, FRCPC (&) Department of Anesthesiology and Pain Medicine, University of Ottawa Heart Institute, University of Ottawa, Ottawa, ON, Canada e-mail: [email protected]