ACC / AHA · 2025

Acute Coronary Syndromes (STEMI and NSTE-ACS) — Management Guideline

Source: 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes, Circulation

✓ Edition checked 3 Oct 2026 — ACC / AHA 2025 is the current edition as of this date.

View the official source ↗

Guideline: Strong Guideline: Conditional Guideline: Not recommended ClinicoQ pathway suggestion (not from the cited guideline)

Diagnosis

Diagnostic criteria Acute coronary syndrome covers ST-elevation myocardial infarction (STEMI) and non-ST-elevation ACS (NSTE-ACS: NSTEMI and unstable angina). Suspect ACS in acute chest pain or anginal equivalents; the 12-lead ECG within 10 minutes of first medical contact separates STEMI (immediate reperfusion pathway) from NSTE-ACS (risk-stratified pathway). Changes in high-sensitivity troponin within the normal range but below the 99th percentile can also signal ischemia and may warrant further evaluation. Separate source: the Fifth Universal Definition of Myocardial Infarction (ESC/ACC/AHA/WHF consensus, August 2026) classifies myocardial infarction as primary (spontaneous, from a primary acute coronary pathology), secondary (oxygen supply-demand imbalance from another acute condition), or procedure-related, replacing the numerical Type 1-5 system, and defines myocardial injury with sex-specific 99th percentile troponin thresholds.

⚠ Alarm features (investigate before diagnosing)

ST-segment elevation or new left bundle branch block with ongoing ischemic symptoms
Hemodynamic instability, cardiogenic shock, or acute heart failure (Killip class II-IV)
Ventricular arrhythmias or high-degree AV block
Ongoing or recurrent ischemic pain despite treatment
Oxygen saturation below 90%

Initial workup

Test	When to order
12-lead ECG	Within 10 minutes of first medical contact in suspected ACS; repeat if symptoms change or persist.
High-sensitivity cardiac troponin (serial)	To rule in or rule out MI; repeat intervals are 1-2 hours for hs-cTn assays and 3-6 hours for conventional troponin. A single early negative result does not exclude ACS in high-risk patients.
Coronary angiography	Immediate in STEMI (primary PCI) and in cardiogenic shock; during hospitalization in NSTE-ACS at intermediate or high ischemic risk.

Decision Points

❓ Does the 12-lead ECG show ST-segment elevation (STEMI)?

Yes, STEMI → STEMI: reperfusion

No, NSTE-ACS (NSTEMI or unstable angina) → NSTE-ACS: invasive strategy and revascularization

Treatment

Initial assessment and immediate treatment (all suspected ACS)

1 Aspirin loading dose Strong (Guideline recommendation) — irrespective of final management strategy

Dose: 162-325 mg orally, chewed and non-enteric-coated, as soon as possible; give the loading dose even in patients already taking aspirin. Then 75-100 mg orally daily
Duration: Loading dose once; maintenance long-term
Evidence level: High
Avoid if: Absolute contraindication to aspirin; with ticagrelor, keep the maintenance dose at 100 mg daily or below
If no response: Give a P2Y12 inhibitor (see antiplatelet pathway) and follow the STEMI or NSTE-ACS pathway

2 Supplemental oxygen only if hypoxic Guideline recommendation — give oxygen only when saturation is below 90%; routine use at higher saturation has no benefit

Dose: Oxygen only when saturation is below 90%, to bring saturation to 90% or higher
Duration: Until saturation 90% or higher
Evidence level: Moderate
Avoid if: —

STEMI: reperfusion

1 Primary PCI Strong (Guideline recommendation) — preferred reperfusion strategy; the time target is within 90 minutes of first medical contact in a PCI-capable hospital, or within 120 minutes when transfer is needed

Dose: —
Duration: Emergency procedure
Evidence level: High
Avoid if: —
If no response: If primary PCI cannot be achieved within 120 minutes, give fibrinolysis

2 Fibrinolysis, then immediate transfer to a PCI-capable centre Guideline recommendation — when primary PCI cannot be performed within 120 minutes, unless contraindicated

Dose: Per product labeling; administer within 30 minutes of arrival
Duration: Single treatment
Evidence level: High
Avoid if: Standard fibrinolytic contraindications (check labeling). Not for ST-segment depression alone, unless true posterior STEMI is suspected
If no response: Immediate angiography with rescue PCI if reperfusion fails

3 Cardiogenic shock: emergency revascularization of the culprit vessel Guideline recommendation — emergency culprit-vessel revascularization is indicated; routine PCI of non-infarct-related arteries at the time of PCI is advised against; a microaxial flow pump may be used in selected patients

Dose: —
Duration: Emergency
Evidence level: High
Avoid if: —

NSTE-ACS: invasive strategy and revascularization

1 Invasive approach with intent to revascularize during hospitalization Strong (Guideline recommendation) — patients at intermediate or high risk of ischemic events

Dose: —
Duration: During the index admission
Evidence level: High
Avoid if: Limited life expectancy or patient preference against revascularization (individualize)
If no response: Choose PCI or CABG by the complexity of coronary disease and comorbidities; complete revascularization is recommended

2 Upstream P2Y12 inhibitor if angiography will be delayed beyond 24 hours Guideline recommendation (may be considered) — NSTE-ACS with a planned invasive strategy and angiography timing over 24 hours

Dose: Clopidogrel or ticagrelor (doses in the antiplatelet pathway)
Duration: Until angiography
Evidence level: Low
Avoid if: High bleeding risk or likelihood of urgent surgery

Antiplatelet and antithrombotic therapy, DAPT duration

1 Ticagrelor or prasugrel (preferred over clopidogrel when undergoing PCI) Strong (Guideline recommendation) — ticagrelor or prasugrel in preference to clopidogrel in ACS patients undergoing PCI (Class 1)

Dose: Ticagrelor: loading 180 mg then 90 mg twice daily. Prasugrel (PCI only): loading 60 mg, then 10 mg daily if body weight is 60 kg or above and age is under 75 years, or 5 mg daily if body weight is under 60 kg or age is 75 years or above (use caution). Clopidogrel (if neither can be used): without a fibrinolytic, loading 300 or 600 mg then 75 mg daily; with a fibrinolytic, loading 300 mg if age is 75 years or under, or 75 mg without a loading dose if over 75 years, then 75 mg daily
Duration: At least 12 months with aspirin in patients not at high bleeding risk
Evidence level: High
Avoid if: Prasugrel: prior stroke or TIA (Class 3, harm); active bleeding; high bleeding risk. Keep aspirin at 100 mg daily or below with ticagrelor
If no response: Choose the duration and any bleeding-reduction strategy in the next steps

2 Default DAPT duration after ACS Strong (Guideline recommendation) — Class 1 in patients who are not at high bleeding risk

Dose: Aspirin plus a P2Y12 inhibitor
Duration: At least 12 months
Evidence level: High
Avoid if: High bleeding risk (see the strategies in the next steps)

3 Ticagrelor monotherapy after the first month of DAPT Strong (Guideline recommendation) — Class 1, level A in patients who tolerated DAPT with ticagrelor, to reduce bleeding

Dose: Ticagrelor 90 mg twice daily alone, stopping aspirin
Duration: From at least 1 month after PCI
Evidence level: High
Avoid if: Not tolerating ticagrelor; there is no equivalent recommendation for prasugrel monotherapy

4 De-escalation from ticagrelor or prasugrel to clopidogrel after 1 month Guideline recommendation (Class 2b, may be reasonable) — to reduce bleeding risk in patients undergoing PCI

Dose: Clopidogrel 75 mg once daily
Duration: From 1 month after PCI
Evidence level: Moderate
Avoid if: Patients at high ischemic risk

5 Patients who need long-term oral anticoagulation, and gastrointestinal protection Guideline recommendation — proton pump inhibitor in patients at gastrointestinal bleeding risk; aspirin withdrawal after 1-4 weeks when anticoagulation is needed (class per the guideline summaries)

Dose: Proton pump inhibitor in patients at risk of gastrointestinal bleeding. With an oral anticoagulant, stop aspirin 1-4 weeks after PCI and continue a P2Y12 inhibitor (preferably clopidogrel) with the anticoagulant
Duration: Per strategy
Evidence level: Moderate
Avoid if: —

Medical therapy before discharge (secondary prevention)

1 High-intensity statin Strong (Guideline recommendation) — all patients with ACS

Dose: Atorvastatin 40-80 mg or rosuvastatin 20-40 mg once daily; concurrent ezetimibe is an option
Duration: Long-term
Evidence level: High
Avoid if: Pregnancy; active liver disease; statin intolerance (offer non-statin lipid-lowering therapy)
If no response: Add a non-statin if LDL-C stays 70 mg/dL or above on the maximally tolerated statin (consider adding if 55-69 mg/dL)

2 Oral beta-blocker Strong (Guideline recommendation) — early (under 24 hours) initiation to reduce reinfarction and ventricular arrhythmias

Dose: Per product labeling
Duration: Start within 24 hours
Evidence level: High
Avoid if: Acute heart failure (Killip II-IV), low cardiac output or risk of cardiogenic shock, PR interval over 0.24 s, second- or third-degree block without a pacemaker, severe bradycardia, active bronchospasm

3 ACE inhibitor or ARB Guideline recommendation — in patients with LVEF 40% or below, hypertension, diabetes, or anterior STEMI; also reasonable in patients not at high risk

Dose: Per product labeling
Duration: Long-term
Evidence level: High
Avoid if: Pregnancy; angioedema; hyperkalaemia; hypotension

✕ Treatments the guideline advises against

Routine supplemental oxygen when oxygen saturation is 90% or higher: The 2025 guideline recommends oxygen only for saturation below 90%; routine use at higher saturation has no benefit.

Routine PCI of non-infarct-related arteries at the time of PCI in cardiogenic shock: The guideline states that emergency culprit-vessel revascularization is indicated and routine non-culprit PCI is not recommended.

Fibrinolytic therapy when only ST-segment depression is present: Fibrinolysis should not be given for ST depression alone unless a true posterior STEMI is suspected.

Prasugrel in patients with a history of stroke or TIA: The 2025 guideline gives a Class 3 (harm) recommendation because of net harm with prasugrel in this group.

Maintenance aspirin above 100 mg daily in patients treated with ticagrelor: Aspirin doses of 100 mg daily or below should always be used with ticagrelor, based on the PLATO analysis.

⚠️ This is an educational summary of current international clinical practice guidelines and does not replace individualized clinical judgment. Final treatment decisions remain the responsibility of the treating physician.