From the Guidelines
Type 1 and Type 2 NSTEMI differ primarily in their underlying mechanisms, with Type 1 resulting from spontaneous plaque rupture, erosion, or dissection in a coronary artery, and Type 2 occurring when myocardial oxygen demand exceeds supply due to conditions like severe anemia, hypotension, or tachyarrhythmias, without plaque disruption. The distinction between these two types is crucial, as it guides treatment strategies and outcomes. According to the 2017 AHA/ACC clinical performance and quality measures for adults with ST-elevation and non-ST-elevation myocardial infarction 1, Type 1 NSTEMI is an event related to atherosclerotic plaque disruption with superimposed thrombus formation in a coronary artery, resulting in acute reduction in myocardial blood supply and/or distal embolization with subsequent myonecrosis. On the other hand, Type 2 NSTEMI is myocardial injury caused by conditions other than coronary artery disease that results in an imbalance between myocardial oxygen supply and/or demand.
Key differences in treatment approaches between Type 1 and Type 2 NSTEMI include:
- Dual antiplatelet therapy, anticoagulation, and early invasive strategy with coronary angiography for Type 1 NSTEMI
- Treatment of the underlying cause, such as blood transfusion for anemia, rate control for tachyarrhythmias, or vasopressors for hypotension, for Type 2 NSTEMI
- Cardiac biomarker monitoring, ECG assessment, and risk stratification for both types
The 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes 1 also emphasizes the importance of distinguishing between Type 1 and Type 2 NSTEMI, as well as the need for evidence-based diagnostic and therapeutic strategies to improve outcomes for patients with NSTE-ACS. In summary, accurate diagnosis and differentiation between Type 1 and Type 2 NSTEMI are essential to guide treatment strategies and improve patient outcomes, with a focus on reducing morbidity, mortality, and improving quality of life 1.
From the Research
Difference between NSTEMI Type 1 and Type 2
- NSTEMI Type 1 is defined as an acute atherothrombotic event 2
- NSTEMI Type 2 is defined as a result of other causes of mismatch of myocardial oxygen supply and demand 2
- The main difference between the two types is the underlying cause of the myocardial infarction, with Type 1 being related to a blockage in the coronary arteries and Type 2 being related to other factors such as hypertension, hypotension, or tachycardia
- The management and treatment of NSTEMI Type 1 and Type 2 may differ, with Type 1 typically requiring more aggressive treatment with anticoagulants and antiplatelet agents 3
- The prognosis and outcomes of NSTEMI Type 1 and Type 2 may also differ, with Type 1 generally having a poorer prognosis due to the higher risk of recurrent myocardial infarction and death 2
Clinical Characteristics and Management
- NSTEMI patients should be initiated on anticoagulation and antiplatelet therapy as soon as possible after admission 3
- The use of an early invasive strategy, including coronary angiography and percutaneous coronary intervention (PCI), has been shown to improve outcomes in NSTEMI patients 4, 5, 6
- The timing of PCI is important, with early PCI (within 24 hours) associated with lower risk of recurrent myocardial infarction and death 4, 6
- The use of ticagrelor pretreatment has been shown to reduce periprocedural myocardial injury in NSTEMI patients undergoing PCI 5