Secondary prevention after myocardial infarction

What it is

Secondary prevention after myocardial infarction is the medication a patient is discharged on after an acute coronary syndrome and keeps taking. The recommended discharge medications are six:

• Aspirin
• Clopidogrel
• A B-blocker
• ACE inhibitors
• Statins
• Nitrates

These are separate from what is given at the time of initial presentation, which is aspirin 325mg, O2, nitrate, morphine and B-blockers, with antithrombin therapy and glycoprotein IIb/IIIa inhibitors if PCI is done.

How it is treated

Aspirin and clopidogrel are not continued for the same length of time, and this is the point most often asked. Dual antiplatelet therapy after a drug-eluting stent is aspirin plus a thienopyridine such as clopidogrel, for a minimum of 1 year; a second source gives clopidogrel up to 9-12 months after stent placement. Aspirin therapy should be continued indefinitely. So 2 years after stent placement there is no indication to continue clopidogrel, while aspirin goes on.

When atrial fibrillation is also present after a ST-elevation myocardial infarction, the regimen is triple: dual antiplatelet therapy such as aspirin plus clopidogrel, with a vitamin K antagonist to a goal INR of 2.0-3.0. A patient already taking a direct-acting oral anticoagulant instead of warfarin continues that anticoagulant in addition to dual antiplatelet therapy. The duration of triple therapy should be as short as possible, and aspirin can often be discontinued after 1-3 months.

Statins are beneficial for both primary and secondary prevention of cardiovascular disease, and the benefit is greater when the baseline risk is greater. Physical activity carries its own weight here: the most active people had median cardiovascular risk reductions of about 30%-35% compared with the least active.