NSTEMI (Non-ST-Elevation Myocardial Infarction)
Risk stratification, early invasive strategy and secondary prevention for NSTEMI
NSTEMI (Non-ST-Elevation Myocardial Infarction) is caused by partial occlusion of a coronary artery, resulting in myocardial injury without ST elevation. It is defined by a rise and fall in high-sensitivity troponin above the 99th percentile, without ST elevation on ECG. NSTEMI requires urgent risk stratification using the GRACE score to guide the timing of coronary angiography and revascularisation. (NICE NG185, 2020)
What is NSTEMI?
NSTEMI results from partial or temporary occlusion of a coronary artery, causing myocardial injury without the full-thickness damage of a STEMI. The key diagnostic feature is a rise and fall in high-sensitivity troponin (above the 99th percentile) with a characteristic pattern on serial testing at 0 hours and 1–3 hours (NICE NG185 rapid rule-in/rule-out pathway). ECG may show ST depression, T-wave inversion, or may be normal — ST elevation is absent by definition.
Risk stratification — GRACE score
All patients with NSTEMI should be risk-stratified using the GRACE (Global Registry of Acute Coronary Events) score, which predicts in-hospital and 6-month mortality. High risk (GRACE score >140): coronary angiography within 24 hours (NICE NG185). Intermediate risk (GRACE 109–140): angiography within 72 hours. Low risk (GRACE <109): consider non-invasive testing (exercise ECG or myocardial perfusion imaging) before angiography. Haemodynamic instability, ongoing chest pain, or life-threatening arrhythmia require immediate angiography regardless of GRACE score.
Immediate medical management
Antiplatelet therapy: aspirin 300 mg loading dose immediately, then 75 mg OD lifelong. Add a P2Y12 inhibitor — ticagrelor 180 mg loading (preferred for NSTEMI, NICE NG185) or clopidogrel 300 mg if ticagrelor contraindicated. Anticoagulation: fondaparinux 2.5 mg SC OD is the first-line anticoagulant for NSTEMI (NICE NG185) — continue until discharge or up to 8 days; switch to unfractionated heparin at the time of angiography/PCI. Do not give oxygen unless SpO2 <94%.
Medicines after NSTEMI
Post-NSTEMI secondary prevention: dual antiplatelet therapy (aspirin lifelong + ticagrelor 90 mg BD or clopidogrel 75 mg OD for 12 months); high-intensity statin — atorvastatin 80 mg, target LDL <1.8 mmol/L; ACE inhibitor (ramipril), especially if LVEF <40%, diabetes or hypertension; beta-blocker (bisoprolol), particularly if reduced LVEF; eplerenone if LVEF ≤35% with heart failure or diabetes. Medicines should be started within 24 hours and continued long-term as prescribed.
Recovery and secondary prevention
After NSTEMI, cardiac rehabilitation is strongly recommended — attend all sessions. Driving: DVLA requires a minimum of 4 weeks off after NSTEMI managed medically; 1 week after successful PCI. Lifestyle changes are essential: stop smoking, follow a Mediterranean diet, exercise regularly and manage weight. An echocardiogram at 6–12 weeks assesses LVEF — if <35%, ICD assessment may be required. Annual review of lipids, blood pressure and medication adherence is important. All content based on careful evaluation of NICE NG185 (2020).