Use of Antiplatelet Drugs After Cardiac Operations

Once- versus Twice-Daily Aspirin in Patients at High Risk of Thrombotic Events: Systematic Review and Meta-Analysis

BACKGROUND

Acetylsalicylic acid (ASA) is a frequently used antiplatelet agent, although some individuals have reduced antiplatelet responses on ASA, with recurrent ischemic events. It has been proposed that shortening the ASA dosing interval may overcome the time-dependent renewal of the drug target, leading to a greater antiplatelet effect. We conducted a systematic review of randomized controlled trials (RCTs) to determine the efficacy of once- versus twice-daily ASA in conditions with increased platelet turnover.

METHODS

We conducted a systematic review and meta-analysis by searching the CENTRAL, MEDLINE, and Embase databases for RCTs assessing once- versus twice-daily ASA. Data were screened, extracted, and appraised by two independent reviewers, and were pooled using a random-effects model. The primary outcomes were major adverse cardiovascular events (MACEs) and serum thromboxane B2 (TxB2). Other pharmacodynamic measures were retrieved as secondary outcomes. Results were reported as mean differences with corresponding 95% confidence intervals (CIs). We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Seven RCTs were included, enrolling 379 participants overall. None of the studies reported clinical outcomes. Pooled results showed that compared with once-daily ASA, twice-daily ASA was associated with a decrease in mean TxB2 of 1.42 ng/mL (95% CI - 2.71 to - 0.13; I² = 66%). We found no differences in subgroup analyses based on disease subtype, trial blinding, or trial design. A greater antiplatelet activity of the twice-daily regimen was also found when using PFA-100-ADP methods, although not when using the VerifyNow, LTA-AA, and multiplate methods.

CONCLUSIONS

Twice-daily ASA was associated with a greater antiplatelet effect compared with standard once-daily ASA.

Association of Adenosine Diphosphate-Induced Platelet Maximum Amplitude With Postoperative Bleeding and Blood Transfusions in Patients Undergoing Coronary Artery Bypass Grafting

OBJECTIVES

To investigate the association of adenosine diphosphate (ADP)-induced platelet maximum amplitude (MA_ADP) with postoperative bleeding and blood product transfusions in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB).

DESIGN

This single-center observational study recruited 200 patients who underwent elective, first-time, isolated CABG with CPB. A rapid thromboelastography with platelet mapping test was conducted for all patients before the surgery. Patients were categorized by the preoperative MA_ADP into ≤50 mm (MA_ADP ≤50 group [n = 87]) and MA_ADP >50 mm (MA_ADP >50 group [n = 113]). The primary outcome was postoperative bleeding at 6 and 24 hours as measured by chest tube drainage volume. The perioperative blood product transfusions, postoperative complications, postoperative time course, and in-hospital mortality also were evaluated.

SETTING

University hospital.

PARTICIPANTS

Adult patients scheduled to undergo isolated primary CABG with CPB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The study included 200 patients who underwent CABG with CPB. MA_ADP was >50 mm in 113 (56.5%) patients (MA_ADP >50 group). Compared with the MA_ADP >50 group, the postoperative chest tube drainage volume at 6 and 24 hours was significantly greater in the patients with MA_ADP ≤50 mm (476.90 ± 156.36 mL v 403.36 ± 133.24 mL; p < 0.001 and 935.86 ± 318.43 mL v 667.21 ± 222.75 mL; p < 0.001, respectively). The consumption of blood products in patients with MA_ADP ≤50 mm was significantly more than those with MA_ADP >50 mm. The durations of intensive care unit stay and length of postoperative hospital stay were markedly longer in the MA_ADP ≤50 group than in the MA_ADP >50 group (p = 0.001 and p = 0.005; respectively). There were no significant differences in adverse outcomes between the 2 groups except for the postoperative atrial fibrillation, which occurred more in the MA_ADP ≤50 group than in the MA_ADP >50 group (8.05% v 1.77%; p = 0.043). MA_ADP (area under the receiver operating characteristic curve of 0.767; p < 0.001) was demonstrated to have significant ability to predict bleeding tendency, with a sensitivity of 76.2% and a specificity of 69.0%.

CONCLUSIONS

Preoperative MA_ADP may play a potential role in the prediction of postoperative bleeding and allogeneic blood transfusions and guide clinicians in perioperative management of patients undergoing CABG with CPB.