Managing Acute Coronary Syndromes

Guides ACS management pathways with TIMI/GRACE scoring and intervention timing.

Why This Skill Exists

Acute coronary syndromes (ACS) encompass STEMI, NSTEMI, and unstable angina — together representing the most time-critical diagnoses in cardiology. Door-to-balloon time of ≤ 90 minutes for STEMI remains a national quality benchmark. For NSTEMI, the GRACE score drives timing of invasive strategy (immediate, early, or delayed), and misclassification directly impacts mortality. The 2021 ACC/AHA Guideline for Coronary Artery Revascularization and 2014 AHA/ACC NSTE-ACS guideline define evidence-based treatment algorithms that must be followed precisely.

Errors in ACS management — delayed cath lab activation, failure to administer antiplatelet loading, or inappropriate discharge of an unstable patient — carry among the highest malpractice liability in emergency cardiology.

Checkpoint A: Pre-Draft Intake (Mandatory)

What is the ACS presentation — STEMI, NSTEMI, or unstable angina? (default: "ACS type not classified")
What is the time of symptom onset and time of first medical contact? (default: "Timing not documented")
What was the initial ECG finding? (default: "ECG not provided")
What are the serial troponin values (high-sensitivity preferred)? (default: "Troponin trend not available")
What are the TIMI and/or GRACE risk scores? (default: "Not yet calculated")
Has antiplatelet and anticoagulant therapy been initiated? (default: "Loading status unknown")
Is the patient hemodynamically stable? (default: "Hemodynamic status not documented")
Are there contraindications to anticoagulation, antiplatelet agents, or fibrinolysis? (default: "None known")

Documents to Request

Serial 12-lead ECGs (at presentation, post-intervention, and any with symptoms)
Serial troponin values with timestamps (hs-cTnT or hs-cTnI)
Current medication list including antiplatelets and anticoagulants
Prior cardiac catheterization or revascularization history
Echocardiogram (new or recent)
BMP, CBC, coagulation studies, lipid panel
BNP/NT-proBNP if available
Hemodynamic monitoring data if in CCU/ICU

Step 1: ACS Classification and Initial Risk Stratification

ACS Diagnostic Criteria:

| Type | ECG | Troponin | Clinical | |------|-----|----------|---------| | STEMI | ST elevation meeting criteria or new LBBB | Elevated (confirms but do not wait for results) | Chest pain/anginal equivalent | | NSTEMI | ST depression, T-wave inversion, or non-diagnostic | Elevated above 99th percentile URL with rise/fall pattern | Ischemic symptoms | | Unstable angina | May be normal or show ischemic changes | Normal (serial) | New-onset, crescendo, or rest angina |

TIMI Risk Score for NSTE-ACS (0–7 points):

| Factor | Points | |--------|--------| | Age ≥ 65 | 1 | | ≥ 3 CAD risk factors (family Hx, HTN, DM, hyperlipidemia, smoking) | 1 | | Known CAD (≥ 50% stenosis) | 1 | | ASA use in prior 7 days | 1 | | ≥ 2 anginal episodes in prior 24 hours | 1 | | ST deviation ≥ 0.5 mm | 1 | | Elevated cardiac biomarker | 1 |

| Score | 14-day Death/MI/Urgent Revasc Risk | |-------|-------------------------------------| | 0–2 | Low (< 8.3%) | | 3–4 | Intermediate (13–20%) | | 5–7 | High (26–41%) |

GRACE Score (6-month mortality post-ACS): Variables: age, HR, SBP, creatinine, Killip class, cardiac arrest at admission, ST deviation, elevated cardiac enzymes.

Low risk: < 108 (< 3% mortality)
Intermediate: 109–140 (3–8%)
High risk: > 140 (> 8%)

Step 2: STEMI Management Pathway

Time-Critical Benchmarks:

First medical contact to ECG: ≤ 10 minutes
Door-to-balloon (D2B): ≤ 90 minutes at PCI-capable center
Door-in to door-out (transfer): ≤ 30 minutes at non-PCI center
First medical contact to device: ≤ 120 minutes if transfer needed
If PCI not available within 120 minutes: fibrinolysis within 30 minutes of arrival

Initial STEMI Medications (Concurrent with Cath Lab Activation):

Aspirin 325 mg (chewed, non-enteric-coated)
P2Y12 inhibitor loading: ticagrelor 180 mg OR prasugrel 60 mg (preferred over clopidogrel 600 mg)
Anticoagulation: UFH bolus 60 IU/kg (max 4000 IU) + 12 IU/kg/hr infusion OR bivalirudin
Supplemental O₂ only if SpO₂ < 90%
Nitroglycerin SL × 3 (avoid if SBP < 90, RV infarct, or PDE5 inhibitor use within 24–48 hours)
Morphine only if pain refractory to nitrates (caution: may delay P2Y12 absorption)

Killip Classification (Acute HF Severity in MI):

| Class | Findings | In-Hospital Mortality | |-------|----------|----------------------| | I | No HF signs | 6% | | II | Rales, S3, JVD | 17% | | III | Pulmonary edema | 38% | | IV | Cardiogenic shock | 81% |

Step 3: NSTEMI/UA Management Pathway

Invasive Strategy Timing Based on Risk:

| Timing | Criteria | |--------|---------| | Immediate (< 2 hours) | Hemodynamic instability, refractory angina, sustained VT/VF, acute HF | | Early (< 24 hours) | GRACE > 140, troponin rise/fall, new ST changes | | Delayed (25–72 hours) | GRACE 109–140, diabetes, eGFR < 60, LVEF < 40%, prior PCI/CABG | | Ischemia-guided (selective) | Low risk: TIMI 0–2, GRACE < 109, troponin negative, no recurrent symptoms |

Medical Therapy for NSTE-ACS:

Aspirin 162–325 mg loading + 81 mg daily maintenance
P2Y12 inhibitor: ticagrelor 180 mg load → 90 mg BID or clopidogrel 300–600 mg load → 75 mg daily
Anticoagulation: UFH, enoxaparin (1 mg/kg BID), fondaparinux (2.5 mg daily), or bivalirudin
Beta-blocker: initiate within 24 hours if no contraindications (avoid if Killip ≥ III)
High-intensity statin: atorvastatin 80 mg or rosuvastatin 40 mg (start immediately)
ACEi/ARB: within 24 hours for anterior MI, HF, or LVEF ≤ 40%

Step 4: Post-ACS Risk Reduction

Discharge Medication Checklist (ABCDE):

Antiplatelet: aspirin + P2Y12 (DAPT minimum 12 months post-ACS)
Beta-blocker: continue indefinitely for LVEF ≤ 40%; at least 3 years for all ACS
Cholesterol: high-intensity statin; target LDL < 70 mg/dL (< 55 per ESC)
Diabetes/Diet: glycemic optimization; cardiac diet counseling
Exercise/Education: cardiac rehab referral (Class I, all ACS); smoking cessation

Risk Factor Targets Post-ACS:

LDL < 70 mg/dL (add ezetimibe, then PCSK9 inhibitor if not at goal)
BP < 130/80 mmHg
HbA1c < 7% (individualized)
Smoking cessation with pharmacotherapy support
Cardiac rehabilitation enrollment within 2–4 weeks of discharge

Step 5: Complications and Mechanical Sequelae

Mechanical Complications of MI (typically days 3–7):

Free wall rupture: sudden hemodynamic collapse, tamponade → emergent surgery
VSD: new harsh holosystolic murmur, step-up in O₂ at RV level → surgical/percutaneous closure
Papillary muscle rupture: acute severe MR, flash pulmonary edema → emergent surgery
LV aneurysm: persistent ST elevation weeks post-MI, mural thrombus risk

Arrhythmic Complications:

VT/VF within 48 hours of STEMI: does not independently predict long-term arrhythmia risk — reassess ICD need later
Complete heart block in inferior MI: usually transient; monitor, temporary pacing if symptomatic
Complete heart block in anterior MI: usually indicates extensive septal necrosis; high-grade, likely needs permanent pacemaker

Checkpoint B: Post-Draft Alignment (Mandatory)

Is the ACS type (STEMI/NSTEMI/UA) clearly classified with supporting criteria?
Are TIMI and/or GRACE scores calculated and documented?
Is the reperfusion strategy and timing benchmark documented?
Are all acute medications with loading doses documented?
Is the discharge plan complete with DAPT duration and risk-factor targets?

Quality Audit

[ ] ACS classified as STEMI, NSTEMI, or unstable angina with diagnostic criteria cited
[ ] Time of symptom onset and first medical contact documented
[ ] TIMI score calculated for NSTE-ACS with component details
[ ] GRACE score calculated with 6-month mortality risk category
[ ] Reperfusion timing benchmarks documented (D2B or fibrinolysis time)
[ ] Killip class documented for STEMI patients
[ ] Antiplatelet loading doses and agents documented
[ ] Anticoagulation strategy specified with dosing
[ ] Invasive strategy timing justified by risk category
[ ] Post-PCI TIMI flow and procedural result documented
[ ] Discharge medications reviewed against ABCDE checklist
[ ] DAPT duration specified with rationale
[ ] Cardiac rehabilitation referred
[ ] Mechanical complications screened or surveillance planned
[ ] Follow-up plan with LVEF reassessment at 3 months

Guidelines

In STEMI, never delay cath lab activation to wait for troponin results — the diagnosis is clinical and electrocardiographic.
Ticagrelor or prasugrel are preferred over clopidogrel in ACS (PLATO and TRITON-TIMI 38 trials), unless contraindicated or high bleeding risk.
Prasugrel is contraindicated in prior stroke/TIA and generally avoided in age ≥ 75 or weight < 60 kg.
Do not routinely administer morphine in ACS — it delays gastric absorption of oral P2Y12 inhibitors and has been associated with worse outcomes.
All ACS patients should receive high-intensity statin therapy regardless of baseline LDL — in-hospital initiation improves adherence.
Beta-blockers should not be given acutely if Killip class ≥ III, SBP < 100, HR < 60, or suspected cocaine use.
Early invasive strategy is preferred over ischemia-guided for NSTEMI patients with GRACE > 140 or recurrent ischemia.
Document all time metrics (symptom onset, FMC, ECG, balloon) — these are CMS quality measures and accreditation requirements.