NSTEMI management

Subtotal coronary occlusion causing subendocardial ischaemia with troponin elevation. Management centres on risk stratification (GRACE score) to determine timing of invasive angiography — not all NSTEMIs need emergent catheterisation. Initial medical management is shared with the broader ACS approach.

quick recognition

ischaemic symptoms (chest pain, dyspnoea, diaphoresis) ± dynamic ECG changes (ST depression, T-wave inversion, or transient ST elevation)
troponin elevated above 99th percentile with rise/fall pattern
no persistent ST elevation (distinguishes from STEMI)
normal ECG does not exclude NSTEMI

risk stratification

GRACE score

Determines timing of invasive strategy — TIMACS (2009) showed early intervention (within 24h) reduced death/MI/stroke in high-risk (GRACE >140) patients.

Variables: age, HR, SBP, creatinine, Killip class, cardiac arrest at admission, ST deviation, troponin elevation.

timing of angiography

Risk category	Features	Timing
very high	ongoing ischaemia, haemodynamic instability, life-threatening arrhythmia, mechanical complications	immediate (<2h)
high	GRACE >140, dynamic ECG changes, rising troponin	early (within 24h)
intermediate	GRACE 109–140, diabetes, CKD, prior PCI/CABG, LVEF <40%	routine invasive (<72h)
low	GRACE <109, no recurrent symptoms, no high-risk features	non-invasive testing; angiography if symptoms recur or positive stress test

initial medical management

See Acute Coronary Syndromes for the full ACS cocktail. Key points specific to NSTEMI:

antiplatelet

ASA 160–325 mg chewed + P2Y12 inhibitor
ticagrelor preferred over clopidogrel (PLATO trial)
prasugrel: load at time of PCI (not upstream) once anatomy known — avoid if prior stroke/TIA
clopidogrel: if ticagrelor/prasugrel contraindicated, or if CABG likely (shorter offset)

anticoagulation

Agent	Notes
UFH	standard; weight-based dosing
enoxaparin	alternative; avoid switching between UFH and enoxaparin
fondaparinux	lowest bleed risk; requires UFH bolus if proceeding to PCI (catheter thrombosis risk)

Continue for 48h or until discharge/revascularisation. See heparins for dosing.

adjunctive

beta-blocker within 24h (avoid in decompensated HF, haemodynamic instability)
ACEi/ARB within 24h if anterior MI, HF, LVEF <40%, HTN, or diabetes
high-intensity statin (atorvastatin 80 mg or rosuvastatin 40 mg) — start regardless of baseline lipids

invasive strategy — what to expect

access: radial preferred
findings guide management: medical therapy, PCI, or CABG referral
multivessel disease: complete revascularisation (staged or index) generally favoured
if CABG needed: hold P2Y12 inhibitor (clopidogrel/ticagrelor 5 days, prasugrel 7 days); continue ASA

special populations

NSTEMI + atrial fibrillation (OAC indication)

triple therapy (ASA + P2Y12 + OAC) for 1–30 days peri-PCI
then dual pathway: clopidogrel + DOAC (drop ASA)
favour clopidogrel as the P2Y12 (most evidence in triple/dual pathway)
see Atrial Fibrillation for anticoagulation detail

NSTEMI + cardiogenic shock

immediate angiography and revascularisation
haemodynamic support as needed (inotropes, mechanical circulatory support)

what NOT to do

routine GP IIb/IIIa inhibitors upstream of angiography
prasugrel loading before coronary anatomy is known
switching between UFH and enoxaparin (increases bleed risk)
delaying high-risk patients (GRACE >140) beyond 24h for angiography