From the Guidelines
Type 2 NSTEMI is defined as myocardial necrosis caused by an imbalance between myocardial oxygen supply and demand due to conditions other than coronary plaque instability, such as hypotension, hypertension, tachyarrhythmias, and anaemia. This condition is characterized by an imbalance between the heart's oxygen supply and demand, leading to myocardial necrosis 1. The mechanisms underlying Type 2 MI include various factors that disrupt the balance between oxygen supply and demand, such as:
- Hypotension
- Hypertension
- Tachyarrhythmias
- Bradyarrhythmias
- Anaemia
- Hypoxaemia
- Coronary artery spasm
- Spontaneous coronary artery dissection (SCAD)
- Coronary embolism
- Coronary microvascular dysfunction 1.
The management of Type 2 NSTEMI focuses on addressing the underlying condition causing the supply-demand mismatch, rather than solely treating the cardiac event itself. This may involve:
- Controlling heart rate
- Correcting anaemia with blood transfusions
- Treating infections with appropriate antibiotics
- Addressing hypotension with fluids or vasopressors as needed The prognosis for Type 2 NSTEMI patients often depends on the severity of the underlying condition, and these patients may still require cardiac monitoring and benefit from cardiology consultation to evaluate for any underlying coronary disease 1.
From the Research
Definition of Type 2 NSTEMI
- Type 2 myocardial infarction (MI) is defined as myocardial necrosis due to an imbalance in supply and demand with clinical evidence of ischemia 2, 3, 4, 5
- This condition occurs when there is a mismatch between myocardial oxygen supply and demand, without atherothrombosis or plaque disruption 6, 4
- Type 2 MI is often associated with non-cardiac conditions such as sepsis, anemia, tachyarrhythmia, hypotension, respiratory failure, and severe hypertension 2
Clinical Scenarios and Diagnosis
- Clinical scenarios that predispose to type 2 MI include non-cardiac surgery, anemia or bleeding requiring transfusion, sepsis, tachyarrhythmia, hypotension, respiratory failure, and severe hypertension 2
- Diagnosis of type 2 MI can be challenging due to discrepancies in definitions, frequency of screening, diagnostic approaches, and methods of adjudication 3
- There is no consensus on the diagnostic criteria for type 2 MI, and further investigation is urgently needed 3, 5
Management and Outcomes
- Management of type 2 MI remains poorly characterized, and there are no clear guidelines for the optimal management of these patients 2, 3, 5
- Inpatient mortality for type 2 MI is significant, with a reported rate of 5% 2
- Antiplatelet and statin prescriptions are often infrequent at discharge, reflecting physician uncertainty about the role of secondary prevention in these patients 2