What is acute coronary syndrome (ACS)?

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From the Guidelines

Coronary syndrome refers to a spectrum of conditions compatible with acute myocardial ischemia and/or infarction, usually due to an abrupt reduction in coronary blood flow, as defined by the American College of Cardiology/American Heart Association task force on practice guidelines 1.

Definition and Causes

Coronary syndrome encompasses a range of conditions, including unstable angina and myocardial infarction (heart attack), collectively known as acute coronary syndrome, as well as stable angina. These conditions occur when the coronary arteries, which supply blood to the heart, become narrowed or blocked by fatty deposits called plaques. When these plaques rupture, blood clots can form, further restricting blood flow.

Symptoms and Diagnosis

Symptoms typically include chest pain or discomfort, shortness of breath, nausea, and sweating. The diagnosis of coronary syndrome is based on clinical criteria, including electrocardiogram (ECG) abnormalities, such as ST-segment elevation or depression, and elevated levels of markers of myocardial necrosis, such as troponin or CK-MB 1.

Treatment and Management

Treatment depends on the severity of the condition but often includes medications like aspirin (81-325mg daily), antiplatelet drugs (such as clopidogrel 75mg daily), statins, beta-blockers, and nitroglycerin for acute symptoms. Severe cases may require procedures like angioplasty with stent placement or coronary artery bypass surgery. Risk factors for coronary syndrome include smoking, high blood pressure, high cholesterol, diabetes, obesity, and family history. Immediate medical attention is crucial if symptoms occur, as prompt treatment significantly improves outcomes by restoring blood flow and minimizing heart muscle damage.

Key Considerations

  • The management of patients with suspected acute coronary syndromes without persistent ST-segment elevation is focused on alleviating ischemia and symptoms, and initiating appropriate therapy if the diagnosis is confirmed 1.
  • The definition of myocardial infarction has been reviewed and updated by a joint consensus document of the European Society of Cardiology and the American College of Cardiology.
  • Prompt treatment of coronary syndrome is critical to improve outcomes and reduce morbidity and mortality.

From the FDA Drug Label

Clopidogrel tablets are indicated to reduce the rate of myocardial infarction (MI) and stroke in patients with non–ST-segment elevation ACS (unstable angina [UA]/non–ST-elevation myocardial infarction [NSTEMI]), including patients who are to be managed medically and those who are to be managed with coronary revascularization Clopidogrel tablets are indicated to reduce the rate of myocardial infarction and stroke in patients with acute ST-elevation myocardial infarction (STEMI) who are to be managed medically.

Coronary Syndrome is also known as Acute Coronary Syndrome (ACS), which includes:

  • Unstable Angina (UA)
  • Non-ST-elevation Myocardial Infarction (NSTEMI)
  • ST-elevation Myocardial Infarction (STEMI) 2

From the Research

Definition of Coronary Syndrome

  • Coronary syndrome, also known as acute coronary syndrome (ACS), is defined as reduced blood flow to the coronary myocardium manifesting as ST-segment elevation myocardial infarction or non-ST-segment elevation ACS, which includes unstable angina and non-ST-segment elevation myocardial infarction 3.
  • ACS is characterized by a sudden reduction in blood supply to the heart and includes ST-segment elevation myocardial infarction (STEMI), non-STEMI (NSTEMI), and unstable angina 4.

Risk Factors and Symptoms

  • Common risk factors for ACS include being at least 65 years of age or a current smoker or having hypertension, diabetes mellitus, hyperlipidemia, a body mass index greater than 25 kg per m2, or a family history of premature coronary artery disease 3.
  • Symptoms most predictive of ACS include chest discomfort that is substernal or spreading to the arms or jaw 3.
  • Chest pain that can be reproduced with palpation or varies with breathing or position is less likely to signify ACS 3.

Diagnosis and Treatment

  • Electrocardiography changes that predict ACS include ST depression, ST elevation, T-wave inversion, or presence of Q waves 3.
  • Elevated troponin levels without ST-segment elevation on electrocardiography suggest non-ST-segment elevation ACS 3.
  • Patients with ACS should receive coronary angiography with percutaneous or surgical revascularization 3.
  • Other important management considerations include initiation of dual antiplatelet therapy and parenteral anticoagulation, statin therapy, beta-blocker therapy, and sodium-glucose cotransporter-2 inhibitor therapy 3.
  • The combination of clopidogrel and aspirin has been shown to be beneficial in patients with ACS, with a reduction in cardiovascular death, myocardial infarction, or stroke 5, 6, 7.

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

6
Research

Aspirin and clopidogrel: a sweeping combination in cardiology.

Current medicinal chemistry. Cardiovascular and hematological agents, 2005

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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