Examqo › Examqo library › Internal medicine · Cardiology
Non-ST-elevation acute coronary syndrome (NSTE-ACS)
In NSTE-ACS the diagnosis rests on high-sensitivity troponin and its change over time, and the timing of angiography follows the risk level — immediate, within 24 hours or selective.
Why it matters in the exam
Questions test three things: telling NSTEMI apart from unstable angina and from a type 2 infarct (supply–demand mismatch, for example in anaemia or tachycardia), choosing the timing of angiography by risk criteria, and antiplatelet therapy — which P2Y12 inhibitor to choose, how long to give dual therapy, and what to do in a patient who also needs an anticoagulant for atrial fibrillation. Gastrointestinal bleeding on dual therapy, and thrombocytopenia or bleeding on ticagrelor, also appear.
A recurring point is how to read troponin: a small stable rise also occurs in kidney failure, heart failure, myocarditis and pulmonary embolism, so the question always looks at the change between two samples and at the clinical picture. Candidates are also asked about drugs started in hospital and continued afterwards: a high-intensity statin, a beta-blocker and an ACE inhibitor when LV function is reduced, and a PPI in patients at risk of gastrointestinal bleeding.
Key points
- The diagnosis rests on high-sensitivity troponin and its dynamic change.
- Very high risk: angiography within 2 hours; high risk: within 24 hours.
- Dual antiplatelet therapy for 12 months, with prasugrel or ticagrelor instead of clopidogrel when possible.
- A type 2 infarct comes from supply–demand mismatch and is treated by fixing the cause.
- Patient with atrial fibrillation: short triple therapy, then a DOAC with clopidogrel.
Summary table
| Risk level | Features | Timing of angiography | Note |
|---|---|---|---|
| Very high risk | Haemodynamic instability, refractory pain, life-threatening arrhythmia, acute heart failure, mechanical complication | Within 2 hours | Managed like STEMI |
| High risk | NSTEMI confirmed by troponin, dynamic ST changes, transient ST elevation, GRACE above 140 | Within 24 hours | Most NSTEMI patients |
| Not high risk | Normal troponin, no ECG changes, low suspicion | Selective, guided by non-invasive testing | CCTA or functional test |
| Antiplatelet therapy | Aspirin + P2Y12 inhibitor | 12 months by default | Prasugrel or ticagrelor preferred over clopidogrel |
| Patient with atrial fibrillation | Also needs an anticoagulant | Short triple therapy, up to one week | Then DOAC + clopidogrel to 12 months |
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
The full version is open to subscribers of: Medical licensing exam (IMLE), Internal medicine, Emergency medicine, Family medicine.
Subscriber? Read the full topic Plans and prices 25 free questions
Sources
- ESC Guidelines for the management of acute coronary syndromes, 2023 — Non-ST-segment elevation acute coronary syndrome: diagnosis, risk and invasive strategy
- Harrison's Principles of Internal Medicine, 21st edition (2022) — Non-ST-Segment Elevation Acute Coronary Syndrome
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.