What is the pharmacological management for patients post-acute coronary syndrome (ACS) or myocardial infarction (MI)?

Pharmacological Management of Post-ACS/MI Patients

All patients following acute coronary syndrome or myocardial infarction must receive dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) for 12 months, high-intensity statin therapy, beta-blockers (if LVEF ≤40%), and ACE inhibitors or ARBs (particularly if LVEF ≤40%, heart failure, diabetes, hypertension, or chronic kidney disease present). 1, 2

Core Pharmacological Regimen

Dual Antiplatelet Therapy (DAPT)

First-Line Regimen:

• Aspirin 75-100 mg daily PLUS ticagrelor (180 mg loading dose, then 90 mg twice daily) is the preferred first-line regimen for all ACS patients 1, 3
• Prasugrel (60 mg loading dose, then 10 mg daily) plus aspirin is an alternative for P2Y12 inhibitor-naïve patients with NSTE-ACS or STEMI undergoing PCI, unless contraindications exist 1, 4
• Ticagrelor or prasugrel are strongly preferred over clopidogrel for ACS patients 1, 3, 5

Duration:

• Default duration is 12 months for all ACS patients who are not at high bleeding risk, regardless of ACS type, stent type, or completeness of revascularization 6, 1
• For ACS patients treated with fibrinolytic therapy, P2Y12 inhibitor therapy should continue for minimum 14 days and ideally at least 12 months 1
• In ACS patients with high bleeding risk (defined as 1-year risk of serious bleeding ≥4% or intracranial hemorrhage risk ≥1%), shortened DAPT duration of 3-6 months may be reasonable 1, 5

Critical Contraindications:

• Never prescribe prasugrel to patients with prior stroke or TIA due to increased cerebrovascular bleeding risk (6.5% vs 1.2% with clopidogrel) 1, 4, 5
• Avoid prasugrel in patients >75 years or weighing <60 kg unless high-risk situations exist 4, 5

Lipid-Lowering Therapy

• Initiate high-intensity statin therapy immediately without delay, targeting LDL-C levels <1.8 mmol/L (<70 mg/dL) 6, 2
• Atorvastatin 80 mg daily has demonstrated benefit in reducing recurrent angina hospitalization (6.2% vs 8.4%) 6
• Registry data show lower 1-year mortality in patients discharged with statin therapy 6

Beta-Blockers

• Beta-blockers are mandatory in all patients with reduced LV systolic function (LVEF ≤40%) 6, 2
• Beta-blockers improve prognosis after myocardial infarction and should be continued after acute coronary syndromes 6
• Do not routinely administer IV beta-blockers in the prehospital setting or during initial ED assessment 6
• Starting oral beta-blockers at low doses is recommended once the patient's condition has stabilized 6

ACE Inhibitors or ARBs

• ACE inhibitors are indicated within 24 hours in all patients with LVEF ≤40% and in patients with heart failure, diabetes, hypertension, or chronic kidney disease 6, 2
• ACE inhibitors are recommended for all other patients to prevent recurrence of ischemic events, with preference given to agents and doses of proven efficacy 6
• ARBs are recommended for patients who are intolerant to ACE inhibitors, with preference given to agents and doses of proven efficacy 6

Aldosterone Antagonists

• Eplerenone is indicated in patients after MI who are already being treated with ACE inhibitors and beta-blockers and who have LVEF ≤35% and either diabetes or heart failure, without significant renal dysfunction 6

Bleeding Risk Mitigation Strategies

Mandatory Gastroprotection

• Prescribe a proton pump inhibitor (PPI) with DAPT in all patients to reduce gastrointestinal bleeding risk - this is a Class I recommendation 1, 3, 2
• Pantoprazole 40 mg once daily is preferred due to lowest propensity for CYP2C19 inhibition among PPIs 1
• Avoid omeprazole or esomeprazole with clopidogrel due to significant reduction in antiplatelet activity 7

Additional Bleeding Risk Reduction

• Use radial artery access over femoral access for PCI when performed by experienced radial operator 1
• Maintain aspirin dose at 75-100 mg daily (not higher doses) when combined with P2Y12 inhibitor 6, 1, 3

Special Clinical Scenarios

Patients Requiring CABG

• If CABG is planned, discontinue clopidogrel 5-7 days before elective surgery 3
• Resume P2Y12 inhibitor therapy after CABG to complete 12 months of DAPT 1, 3
• Continue aspirin perioperatively if bleeding risk allows 3

Extended DAPT Beyond 12 Months

• For patients with history of MI who are at high ischemic risk and have tolerated initial DAPT without bleeding complications, consider extended DAPT with ticagrelor 60 mg twice daily beyond 12 months 1
• High ischemic risk defined as: age ≥50 years plus at least one additional risk factor (age ≥65 years, diabetes requiring medication, second prior spontaneous MI, multivessel CAD, or chronic renal dysfunction with creatinine clearance <60 mL/min) 1

Patients with Low Body Weight

• For patients weighing <60 kg on prasugrel, consider lowering maintenance dose to 5 mg daily due to increased exposure to active metabolite and increased bleeding risk 4

Critical Pitfalls to Avoid

Never Discontinue DAPT Prematurely

• Premature discontinuation of DAPT, especially within the first month after ACS, dramatically increases risk of stent thrombosis, myocardial infarction, and death 1, 3
• Do not discontinue DAPT within first month after stent placement for elective non-cardiac surgery - thrombotic risk is highest in first month after ACS 1

Never Use Clopidogrel as First-Line When Alternatives Available

• Never use clopidogrel as first-line therapy when ticagrelor or prasugrel are available and not contraindicated - this represents suboptimal care for ACS patients 1, 3, 5
• Clopidogrel has 30-40% high on-treatment residual platelet reactivity vs 3% with newer P2Y12 inhibitors 5

Never Fail to Prescribe PPI

• Never fail to prescribe a PPI with DAPT - this simple intervention significantly reduces gastrointestinal bleeding 1, 3

Avoid Prophylactic Antiarrhythmics

• Prophylactic antiarrhythmics are not recommended for patients with suspected ACS or myocardial infarction 6
• Studies showed no improvement in survival to hospital discharge and potential for harm 6

Additional Risk Factor Modification

Mandatory Interventions

• Smoking cessation is mandatory - patients should be clearly informed that smoking is a major risk factor, with referral to smoking cessation clinics and consideration of nicotine replacement therapy 6, 2
• Blood pressure control should be optimized with target diastolic BP <90 mmHg, and <85 mmHg in diabetic patients 2
• Enrollment in structured cardiac rehabilitation program is recommended to promote lifestyle changes and improve adherence to medical regimen 6, 2