Secondary prevention after myocardial infarction

Overview

Five pharmacological pillars initiated in hospital and continued long-term post-MI, unless contraindicated.

•Antiplatelet (DAPT): aspirin 75 mg OD indefinitely + ticagrelor 90 mg BD (preferred) or clopidogrel 75 mg OD for 12 months

•After 12 months step down to aspirin monotherapy; patients with drug-eluting stent must complete full 12-month DAPT course

•High ischaemic / low bleeding risk: consider extended DAPT or rivaroxaban 2.5 mg BD added to aspirin

•Statin: atorvastatin 80 mg OD - start in hospital regardless of baseline LDL; continue indefinitely

•Target LDL <1.8 mmol/L (or >50% reduction) and non-HDL <2.5 mmol/L at 3 months

•ACE inhibitor: ramipril - within 24-48 hours of MI; reduces remodelling, mortality, and reinfarction; especially important if LVEF reduced, heart failure, hypertension, or diabetes

•Beta-blocker: bisoprolol or carvedilol - reduces heart rate, oxygen demand, arrhythmia risk, and sudden cardiac death; continue indefinitely if LVEF ≤40% or heart failure with reduced EF

•Aldosterone antagonist: eplerenone 25-50 mg OD - indicated if LVEF ≤40% AND symptomatic heart failure OR diabetes post-MI; monitor potassium and renal function at 1-2 weeks

⚠️

ACE inhibitor + aldosterone antagonist combination increases risk of hyperkalaemia and AKI - monitor renal function and electrolytes 1-2 weeks after initiation and after dose changes. Avoid if eGFR <30 mL/min/1.73m².

Follow-up

•Medication review and cardiovascular risk factor check at 4-8 weeks in primary care, then annually

•Lipid profile at 3 months to assess statin response

•Driving: avoid for ≥1 week (uncomplicated MI); 4 weeks if Group 2 (HGV/bus) licence

•Sexual activity: can resume after 4 weeks if patient can climb two flights of stairs without symptoms

💡

~20-25% of patients develop clinically significant depression or anxiety post-MI - independently worsens prognosis and reduces medication adherence. Screen with a validated tool (e.g. PHQ-9) at follow-up.

Lipid management - second and third line

🥈 Second-line

•ezetimibe 10 mg OD - if LDL target not met or statin intolerance; ~20% additional LDL lowering

🥉 Third-line

•PCSK9 inhibitors (evolocumab / alirocumab) - very high-risk patients not at target on maximum statin + ezetimibe; up to 60% further LDL reduction

•If ACE inhibitor not tolerated (e.g. dry cough): substitute candesartan or another ARB

ICD

•Consider ICD if LVEF ≤35% persisting ≥40 days post-MI despite optimal medical therapy

•Also indicated for survivors of cardiac arrest due to VT/VF (secondary prevention of sudden cardiac death)

Lifestyle modification

Key lifestyle targets

Smoking cessation - up to 50% reduction in CV mortality within 1 year; offer varenicline, bupropion, or NRT

BP target <130/80 mmHg

Diet - Mediterranean-style; low saturated fat and salt

Exercise - ≥150 min moderate-intensity aerobic activity/week

Weight - BMI 18.5-24.9 kg/m²; waist <94 cm (men), <80 cm (women)

Alcohol - ≤14 units/week spread over ≥3 days

Glycaemic control - HbA1c ≤48 mmol/mol; consider empagliflozin or dapagliflozin (SGLT2i) if diabetes + reduced EF

Cardiac rehabilitation

•Structured multidisciplinary programme over 6-8 weeks - supervised exercise, risk factor education, psychological support, medication adherence

•Reduces all-cause and cardiovascular mortality by ~20-25%; reduces hospital readmission; improves quality of life

•All eligible patients must be offered formal referral at or before discharge; uptake suboptimal in women, older patients, and ethnic minority groups