CHD patients exhibit a high risk of ischemic events despite antiplatelet therapy [31]. Thus, anticoagulation and dual antiplatelet therapy (triple therapy) in patients who are undergoing PCI with stent implantation may be critical for the prevention of cardiovascular events, including stent thrombosis. Two meta-analyses [32, 33] were performed to evaluate the efficacy and safety of NOACs in ACS patients. However, these analyses did not include the results of some pivotal recent trials including the COMPASS [30], COMMANDER HF [29], ENTRUST–AF PCI [27], and AUGUSTUS[26]. Moreover, patients with stable CAD were not included in the two previous meta-analyses. Although one meta-analysis included the COMPASS study, the number of studies included in the analysis is limited [31]. In contrast, we included the latest studies and performed a subgroup analysis for ACS and stable CAD patients. There was a statistical difference between the two subgroups in the intracranial hemorrhage of safety endpoints. The results showed that combined use of NOACs significantly increased the risk of intracranial hemorrhage in patients with ACS compared to those with stable CAD. This may be due to the possibility that ACS patients are often treated with dual antiplatelet therapy, which increases the risk of bleeding. Our sensitivity analysis also suggested that additional treatment of NOACs significantly increased the risk of TIMI major bleeding in patients with CHD after excluding RCT studies [26–28] which included the patients with CHD complicated with atrial fibrillation. This result is also likely to be explained by the fact that most of those patients were treated with single antiplatelet therapy combined with NOACs. Thus, the use of a single antiplatelet agent with NOACs may be a more viable choice in patients with CHD, but more clinical trial data is needed to confirm individualized therapy regimens [34–37].
Additionally, when all the included studies were phase III trials, the combined use of NOACs significantly increased the risk of bleeding in patients with ACS, without improvements in efficacy endpoints, indicating that prolonging the duration of NOACs administration may not benefit patients with ACS but instead increase their risk of bleeding. Most of the results were similar in the phase II trials, which indicated the reliable conclusion of the safety and efficacy endpoints. However, the result of the sensitivity analysis showed that the combination therapy of NOACs did not decrease the risk of ischemic stroke in patients with ACS after excluding all phase II trials, further studies are needed to determine why the longer follow–up time led to poorer prevention of the occurrence of ischemic stroke or further confirm whether combined NOACs with antiplatelet therapy can reduce the incidence of stroke in patients with ACS. Moreover, more RCTs are needed to explore the most optimal duration for combination therapy to ensure a reduced incidence of adverse cardiovascular events with minimal bleeding costs.
More importantly, Kupó et al. [38] performed a meta-analysis involving 28 RCTs and 196,761 patients have identified significant differences in cardiovascular safety among oral anticoagulants. The risk of MI is lowest with rivaroxaban, followed by apixaban and edoxaban, while it is the highest for vitamin K antagonists and dabigatran. Differences in risk of MI may influence the choice of NOACs when combined with antiplatelet therapy for patients with CHD. Nevertheless, future literature show focus on comparing the differences in MACEs and major bleeding among DOAC agents, which is of great importance for guiding the development of personalized antithrombotic regimens for patients with CHD.
The different NOACs dosing in analyzed RCTs could impact the results, especially the safety endpoints. The ATLAS ACS 2–TIMI 51 study [12] suggested that the twice-daily 2.5-mg dose of rivaroxaban reduced the rates of death from cardiovascular causes and any cause, but a survival benefit that was not seen with the twice-daily 5-mg dose. Moreover, the twice-daily 2.5-mg dose also resulted in fewer fatal bleeding events than the twice-daily 5-mg dose. Further, most of the studies have suggested that 2.5 mg of rivaroxaban taken twice daily can exert protective effects on patients with CHD without the risk of major bleeding or fatal bleeding events [13, 22, 39–41]. The latest guidelines indicated that triple medications treatment that lasts one month can be used as a basic administration regimen for patients after PCI, and the use of rivaroxaban can be extended appropriately for those at high risk of ischemic events (one month to six months) [1]. For Apixaban, the APPRAISE–2 study [17] suggested that a dose of 5 mg twice daily was associated with a significant increase in the risk of bleeding, without a significant effect on the incidence of recurrent ischemic events. Further, most of the studies indicated that 2.5 mg twice daily increased major or clinically relevant nonmajor bleeding and a trend toward a reduction in ischemic events [14, 16, 26]. The APPRAISE study [16] also suggested that apixaban at a total daily dose of 10 mg appears attractive for patients at high risk of ischemic events. As for other NOACs, there were no significant differences in drug dosing among studies. For example, Dabigatran significantly reduced coagulation activity and has the potential to reduce cardiovascular events when added to dual antiplatelet treatment in doses 110–150 mg twice daily [15, 28].
In general, in CHD patients with antiplatelet therapy, NOACs exhibited cardiovascular benefits for reducing MACE, cardiovascular death, MI, stroke, and stent thrombosis at the cost of an increased risk of major bleeding events. The large sample size from phase III studies and high–quality design provided solid conclusions for the efficacy and safety of NOAC use in CHD patients.