The initial loading dose of aspirin, a P2Y12 receptor blocker, and intravenous heparin were used to prevent thrombosis (particularly stent thrombosis) during coronary stenting and standard maintenance antithrombotic therapy after implanting a DES composed of DAPT (aspirin and a P2Y12 receptor blocker). Generally, the optimal range for the antithrombotic effect is known as mid-third platelet inhibition. F5D was detected after the coronary stenting procedure; thus, the routine DAPT protocol was applied to coronary intervention, and a decrease in HgB was observed that started on the day of coronary stenting. This finding indicates that a weaker antithrombotic effect is recommended for coronary intervention in patients with F5D. In particular, recurrent mucosal bleeding for daily doses of 90 mg of ticagrelor and 100 mg of aspirin suggests that a weakened antithrombotic effect is also required during maintenance therapy after coronary stenting. The disappearance of mucosal bleeding after stopping the 100 mg of aspirin means that ticagrelor may be more effective than aspirin for controlling mucosal bleeding and maintaining antithrombosis in F5D patients after coronary stenting.