A 82-year-old man with a CFS of 4 (living well with mild frailty) attends the GP for a medication review. He takes Aspirin 75 mg, Clopidogrel 75 mg, Atorvastatin 80 mg, Omeprazole 20 mg, and Ramipril 5 mg. He had a myocardial infarction 18 months ago and a drug-eluting coronary stent was placed. He has had no further cardiac events. According to STOPP/START and current guidelines, which medication change is MOST appropriate?