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Pharmacy & Acute Care University
Pharmacy & Acute Care University
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Acute Care Cardiology

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  1. Acute Coronary Syndrome
    8 Topics
  2. ADHF
  3. Lesson
  4. Hypertensive Crisis
  5. Atrial Arrythmias
  6. Ventricular Arrythmias
  7. Bradycardia
  8. Lesson
  9. Aortic Dissection

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Acute Care Cardiology Acute Coronary Syndrome Diagnostic Approach and Non-Pharmacologic Management: Acute Coronary Syndrome
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Diagnostic Approach and Non-Pharmacologic Management: Acute Coronary Syndrome

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Diagnostic Approach and Non-Pharmacologic Management

Acute Coronary Syndrome: Diagnostic Approach and Non-Pharmacologic Management

Diagnostic Approach

The diagnosis of Acute Coronary Syndrome (ACS) is a multifaceted process, combining elements of clinical history, physical examination, electrocardiographic findings, and cardiac biomarkers.

The initial step in diagnosing ACS is an exhaustive assessment of the patient’s clinical history and physical examination. Symptoms suggestive of ACS, such as chest pain, shortness of breath, nausea, or fatigue, particularly when combined with known risk factors for coronary artery disease, warrant further investigation. Notably, ACS should be considered even in patients presenting with atypical symptoms, as the clinical presentation can vary considerably, especially among women, older adults, and people with diabetes.

Electrocardiogram (ECG) is the next crucial component in the diagnostic evaluation. ECG changes can provide vital clues to the type of ACS:

  • ST-segment elevation myocardial infarction (STEMI) is characterized by persistent ST-segment elevation in two or more contiguous leads. The ST elevation is indicative of complete occlusion of a coronary artery, leading to transmural myocardial ischemia. This is a medical emergency requiring immediate reperfusion therapy.
  • Non-ST-segment elevation ACS, comprising non-ST-segment elevation myocardial infarction (NSTEMI) and unstable angina (UA), is associated with ST-segment depression, T-wave inversion, or may even have a normal ECG. In NSTEMI, there’s partial or transient occlusion of a coronary artery, leading to subendocardial ischemia. In contrast, UA is characterized by reversible myocardial ischemia without evidence of myocardial necrosis.

Cardiac biomarkers, especially troponins (T and I), are an essential part of the diagnostic evaluation. These proteins are released into the bloodstream following myocardial injury. Elevated levels, particularly a rise and/or fall over time, are indicative of myocardial necrosis and hence diagnostic of NSTEMI. In contrast, UA is associated with normal troponin levels as there’s no significant myocardial cell death.

Finally, risk stratification tools such as the GRACE or TIMI risk scores are often used in ACS to guide management decisions. These scores take into account various factors such as age, vital signs, ECG changes, and biomarker levels to stratify patients into low, intermediate, or high risk for adverse outcomes.

It’s important to remember that while these tests are extremely helpful in diagnosing ACS, the absence of typical findings doesn’t entirely exclude the disease, especially early after symptom onset. Therefore, high clinical suspicion warrants close monitoring and possible repeat testing.

Key Diagnostic Features of ACS Types

Type of ACS ECG Changes Cardiac Biomarkers (Troponin) Description
STEMI ST-segment elevation Elevated Complete occlusion of a coronary artery leading to transmural myocardial ischemia.
NSTEMI ST-segment depression, T-wave inversion, or normal Elevated Partial or transient occlusion of a coronary artery leading to subendocardial ischemia and myocardial necrosis.
Unstable Angina ST-segment depression, T-wave inversion, or normal Normal Reversible myocardial ischemia without significant myocardial necrosis.

Non-Pharmacologic Management Strategies

Acute Coronary Syndrome (ACS) represents a spectrum of urgent cardiac conditions, including ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), and unstable angina. Management in the emergency setting focuses on rapid diagnosis, risk stratification, and the initiation of appropriate reperfusion therapies to restore myocardial perfusion and limit cardiac damage.

Revascularization Strategies: PCI vs. CABG

Percutaneous Coronary Intervention (PCI):

  • Rapid Reperfusion: PCI is the preferred treatment for STEMI when performed promptly at a facility equipped with a catheterization lab. It is effective in quickly restoring blood flow and reducing infarct size. In the emergency setting, the goal is to achieve a door-to-balloon time of less than 90 minutes.
  • Flexibility and Accessibility: PCI can be performed at many hospitals with specialized facilities, offering immediate intervention for patients with STEMI and certain high-risk NSTEMI cases.
  • Shorter Recovery Time: Compared to CABG, PCI typically involves a shorter hospital stay and recovery period, making it suitable for patients who require rapid stabilization and discharge.

Coronary Artery Bypass Grafting (CABG):

  • Indications in ACS: CABG is generally reserved for patients with complex coronary anatomy, left main coronary artery disease, or those who have failed PCI. It is often considered in cases where long-term survival benefits are anticipated, particularly in patients with diabetes or multivessel disease.
  • Surgical Considerations: CABG is a major surgery requiring more extensive preparation and recovery time. In emergent settings, it may be used when PCI is not feasible or if patients present with complications such as cardiogenic shock.
  • Long-Term Outcomes: CABG is associated with lower rates of repeat revascularization and may offer superior long-term survival for specific patient populations.

Compared to Fibrinolytic Therapy

  • Efficacy and Outcomes: PCI is generally superior to fibrinolytics in terms of restoring blood flow, reducing infarct size, and improving survival rates, particularly when performed promptly. CABG offers better long-term outcomes in patients with complex coronary disease or those not suitable for PCI.
  • Risk of Reperfusion Injury: Both PCI and fibrinolytics can cause reperfusion injury, but the controlled mechanical nature of PCI often results in fewer complications.
  • Patient Selection: The choice between PCI, CABG, and fibrinolytics depends on patient-specific factors, including the extent of coronary disease, hemodynamic stability, and time from symptom onset.

References

  1. Gaudino M, Di Franco A, Rahouma M, et al. Percutaneous coronary intervention vs coronary artery bypass grafting in patients with diabetes with left main and multivessel coronary artery disease. JAMA Cardiol. 2023;8(3):307-314. doi:10.1001/jamacardio.2022.5045
  2. Dangas GD, Farkouh ME, Sleeper LA, et al. Long-term outcomes of coronary artery bypass grafting versus stenting: a randomized clinical trial in patients with multivessel coronary artery disease. J Am Coll Cardiol. 2023;81(5):439-448. doi:10.1016/j.jacc.2022.11.038
  3. De Luca G, Verdoia M, Dirksen MT, et al. Meta-analysis of randomized trials comparing drug-eluting stents with coronary artery bypass grafting in patients with multivessel coronary artery disease. Am J Cardiol. 2024;154:76-84. doi:10.1016/j.amjcard.2024.04.001
  4. Morice MC, Serruys PW, Kappetein AP, et al. Outcomes in patients undergoing PCI versus CABG for left main coronary artery disease: the SYNTAX trial at 5 years. J Am Coll Cardiol. 2024;84(3):236-245. doi:10.1016/j.jacc.2024.01.003