Dual Antiplatelet Therapy Duration

Dual antiplatelet therapy duration balances stent thrombosis and recurrent ischaemia against bleeding, and is set by the clinical presentation, stent type, ischaemic risk and bleeding risk. The default after acute coronary syndrome is 12 months. In stable coronary disease after stenting it is 6 months. Shorter courses of 1 to 3 months are used when bleeding risk is high, followed by a single antiplatelet drug.

Risk assessment. Use a bleeding risk score and list high-risk features: age 75 or over, anaemia, oral anticoagulant use, chronic kidney disease, previous bleeding, thrombocytopenia and cancer.

Ischaemic risk. Prior myocardial infarction, multivessel disease, diabetes, long stents, bifurcation stenting and recurrent events.

Acute coronary syndrome with stent. Aspirin 75 to 100 mg orally once daily plus ticagrelor 90 mg twice daily (or prasugrel 10 mg, or clopidogrel 75 mg once daily) for 12 months, then aspirin alone.

High bleeding risk. Shorten to 1 to 3 months, then continue the P2Y12 inhibitor alone, or aspirin alone, as directed by the clinician.

Stable disease with stent. Aspirin plus clopidogrel 75 mg once daily for 6 months, or 1 to 3 months in high bleeding risk, then single antiplatelet therapy.

Extended therapy. After myocardial infarction with high ischaemic risk and low bleeding risk, ticagrelor 60 mg orally twice daily with aspirin for up to 36 months.

Atrial fibrillation with a stent. An oral anticoagulant with clopidogrel 75 mg once daily, with aspirin for up to 1 week only. Continue clopidogrel for 6 to 12 months, then the anticoagulant alone. Prefer a direct oral anticoagulant over warfarin.

After bypass surgery. Aspirin plus a P2Y12 inhibitor for 12 months after acute coronary syndrome.

Medical treatment only. Aspirin plus ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily for 12 months.

Special groups. In older adults and chronic kidney disease, favour the shorter course. In pregnancy, discuss with a specialist. In creatinine clearance under 30 mL/min, assume high bleeding risk. In East Africa, drug supply and cost may decide the agent, and a missed supply risks stent thrombosis, so explain this clearly.

Review. At 1, 3, 6 and 12 months, with a plan written in the discharge summary that gives the stop date.

Monitoring. Haemoglobin, platelets, creatinine, bleeding and adherence.

Gastric protection. Pantoprazole 40 mg orally once daily while on dual therapy with high bleeding risk.

Stopping. Stop the second drug on the planned date. Stop earlier only for major bleeding. Do not stop for dental treatment or minor procedures.

Common errors. No stop date, continuing dual therapy for years without an indication, and stopping both drugs after the course.

Referral and escalation. Refer for stent thrombosis symptoms, major bleeding, or need for surgery in the first 6 months after a stent.