From the Guidelines
Non-ST-Elevation Myocardial Infarction (NSTEMI) is a type of heart attack characterized by partial blockage of a coronary artery that causes damage to the heart muscle without showing ST-segment elevation on an electrocardiogram (ECG). It occurs when blood flow to a portion of the heart is severely restricted but not completely blocked, resulting in the death of some heart tissue. NSTEMI is diagnosed through a combination of clinical symptoms (such as chest pain, shortness of breath, nausea, and sweating), cardiac biomarkers (particularly elevated troponin levels in the blood), and ECG changes that may show ST-segment depression or T-wave inversions rather than ST elevations. The partial blockage in NSTEMI is typically caused by a ruptured atherosclerotic plaque and subsequent thrombus formation in a coronary artery. Some key points to consider in the diagnosis and management of NSTEMI include:
- The absence of persistent ST-elevation on an ECG, which differentiates it from ST-Elevation Myocardial Infarction (STEMI) 1
- The importance of cardiac biomarkers, such as troponin, in diagnosing NSTEMI and distinguishing it from unstable angina (UA) 1
- The role of antiplatelet therapy, anticoagulation, beta-blockers, and statins in the management of NSTEMI 1
- The potential benefits of an early invasive strategy with coronary angiography followed by revascularization if appropriate 1 NSTEMI requires prompt medical attention as it indicates significant coronary artery disease and carries risks of progression to complete blockage, heart failure, arrhythmias, and death if not properly managed. The most recent and highest quality study, the 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes, provides a comprehensive approach to the diagnosis and management of NSTEMI 1.
From the FDA Drug Label
For 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, USP have been shown to decrease the rate of a combined endpoint of cardiovascular death, myocardial infarction (MI), or stroke as well as the rate of a combined endpoint of cardiovascular death, MI, stroke, or refractory ischemia. Non-ST-Elevation Myocardial Infarction (NSTEMI) is defined as a type of acute coronary syndrome (ACS) without ST-elevation, characterized by elevated cardiac enzymes or troponin I or T to at least twice the upper limit of normal, and ECG changes compatible with new ischemia (without ST-elevation) 2.
- Key characteristics of NSTEMI include:
- Elevated cardiac enzymes or troponin levels
- ECG changes consistent with ischemia without ST-elevation
- Absence of ST-elevation on electrocardiogram (ECG) The diagnosis of NSTEMI is typically made based on a combination of clinical presentation, ECG findings, and laboratory results, including troponin levels 2.
From the Research
Definition of NSTEMI
- Non-ST-Elevation Myocardial Infarction (NSTEMI) is defined as elevated cardiac biomarkers of necrosis in the absence of persistent ST-segment elevation in the setting of anginal symptoms or other acute event 3.
- It may result from an acute atherothrombotic event ('Type 1') or as the result of other causes of mismatch of myocardial oxygen supply and demand ('Type 2') 3.
Key Characteristics of NSTEMI
- NSTEMI carries a poorer prognosis than most ST-segment elevation events, owing to the typical comorbidity burden of the older NSTEMI patients as well as diverse etiologies that add complexity to therapeutic decision-making 3.
- Patients with NSTEMI are at high risk for atherothrombotic recurrences 4.
- Heart failure is a common and meaningful situation in NSTEMI, which warrants careful management and further investigation to reach stronger evidence for clinical recommendations 5.
Treatment and Management of NSTEMI
- Dual antiplatelet therapy (DAPT) with aspirin and the P2Y12 receptor inhibitor clopidogrel significantly reduces the ischemic events in NSTEMI patients 4.
- Beta-blocker therapy has proven benefit to patients with Killip class II in observational studies and small trials 5.
- Early use of beta-blockers is a quality indicator for the treatment of patients with NSTEMI, and is associated with lower in-hospital mortality and improved clinical outcomes 6.
- Reduced-dose enoxaparin combined with dual-antiplatelet therapy followed by triple-antiplatelet therapy alone (without additional anticoagulation) during subsequent PCI appears safe and may prove efficacious 7.