NSTEMI diagnosis and management

NSTEMI diagnosis and management

NSTEMI diagnosis and management

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NSTEMI Pathophysiology - The Unstable Plaque

Plaque rupture, erosion, and thrombus development

  • Core Mechanism: Rupture of an atherosclerotic plaque triggers platelet aggregation and thrombus formation.

    • The key distinction is a partially occlusive thrombus, which limits but doesn't eliminate blood flow.
    • This leads to subendocardial ischemia and necrosis, hence the elevated cardiac biomarkers (Troponins).
  • Spectrum of ACS:

    • Unstable Angina: Ischemia without necrosis (negative biomarkers).
    • STEMI: A fully occlusive thrombus causing transmural ischemia.

⭐ Plaque rupture most commonly occurs at the shoulder region of the fibrous cap, an area weakened by inflammatory cells.

NSTEMI Diagnosis - The Clinical Picture

  • Clinical Presentation: Substernal chest pain >20 min, often with dyspnea, diaphoresis, or nausea. Atypical symptoms (fatigue, epigastric pain) common in women, diabetics, and the elderly.
  • ECG Findings: Key ischemic changes include ST-segment depression (≥0.5 mm) or dynamic T-wave inversions (≥1 mm). A normal ECG does not rule out NSTEMI.
  • Cardiac Biomarkers: High-sensitivity cardiac troponin (hs-cTn) is the gold standard.
    • Serial measurements (e.g., at 0 and 1-3 hours) are crucial.
    • Look for a characteristic rise and/or fall pattern.

ECG: ST depression vs. T-wave inversion

⭐ A normal initial ECG occurs in up to 20% of NSTEMI cases; repeat ECGs are essential if clinical suspicion remains high.

Risk Stratification - Scoring the Danger

Guides timing of intervention (invasive vs. conservative).

  • TIMI Score: Predicts 30-day risk of death, MI, or revascularization.

    • Age ≥65
    • Markers (positive cardiac)
    • EKG (ST deviation ≥0.5 mm)
    • Risk factors for CAD (≥3: HTN, HLD, DM, smoking, family hx)
    • Ischemia (≥2 anginal events in 24h)
    • CAD (known, stenosis ≥50%)
    • Aspirin use in past 7 days
    • 📌 Mnemonic: AMERICA
  • GRACE Score: More complex, but more accurate for in-hospital & long-term mortality.

⭐ The GRACE score is superior to the TIMI score in predicting mortality, especially in higher-risk patients.

NSTEMI Management - The Action Plan

  • Initial Medical Therapy:
    • DAPT: Aspirin + P2Y12 inhibitor (e.g., Ticagrelor).
    • Anticoagulation: Unfractionated or LMW Heparin.
    • Beta-blockers: Metoprolol (cardioselective).
    • Statin: High-intensity (e.g., Atorvastatin 80 mg).
    • Nitrates for angina relief.

⭐ In patients with NSTEMI and cardiogenic shock or refractory angina, emergent (<2h) coronary angiography is recommended.

High-Yield Points - ⚡ Biggest Takeaways

  • NSTEMI is an ACS with positive cardiac biomarkers (troponin) but no ST-segment elevation on EKG.
  • It is differentiated from Unstable Angina by the presence of elevated troponins, indicating myocardial necrosis.
  • Initial management includes dual antiplatelet therapy (DAPT)-Aspirin plus a P2Y12 inhibitor-and anticoagulation.
  • Risk stratification with TIMI or GRACE scores is crucial to guide therapy toward an early invasive strategy.
  • Beta-blockers reduce myocardial oxygen demand; nitrates provide symptom relief.

Practice Questions: NSTEMI diagnosis and management

Test your understanding with these related questions

A 67-year-old man comes to the emergency department because of retrosternal chest pressure and shortness of breath for 4 hours. The symptoms started while he was walking to work and have only minimally improved with rest. He has a history of type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for 35 years. He appears uncomfortable. His pulse is 95/min. Serum studies show a normal troponin concentration. An ECG shows no abnormalities. Which of the following is the most likely underlying cause of this patient's symptoms?

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Flashcards: NSTEMI diagnosis and management

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What EKG findings (2) are associated with unstable angina? _____

TAP TO REVEAL ANSWER

What EKG findings (2) are associated with unstable angina? _____

ST-segment depression and/or T-wave inversion

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