From the Guidelines
INOCA (Ischemia with No Obstructive Coronary Arteries) and MINOCA (Myocardial Infarction with Non-Obstructive Coronary Arteries) are distinct cardiac conditions characterized by symptoms of heart disease despite relatively clear coronary arteries, with INOCA referring to patients with symptoms of chest pain and evidence of myocardial ischemia without significant blockages, and MINOCA describing patients who have had a heart attack with elevated cardiac biomarkers and non-obstructive coronary arteries. According to the most recent guidelines, including those from the European Society of Cardiology 1, these conditions are more common in women and younger patients than traditional obstructive coronary artery disease. The underlying mechanisms of INOCA and MINOCA include:
- Coronary microvascular dysfunction
- Coronary vasospasm
- Thromboembolism
- Spontaneous coronary artery dissection
- Other non-cardiac causes
Diagnosis and Treatment
The diagnosis of INOCA and MINOCA requires a comprehensive evaluation beyond just coronary angiography, incorporating invasive coronary function testing (CFT) to identify underlying mechanisms of angina 1. Treatment typically involves medications to improve microvascular function and prevent vasospasm, such as:
- Calcium channel blockers
- Nitrates
- Statins Along with traditional risk factor modification, these conditions highlight that not all cardiac ischemia is caused by visible coronary blockages. The 2024 ESC CCS guidelines provide a new vision for the diagnosis and management of ANOCA/INOCA, with an expanded role for invasive CFT and targeted medical therapy to improve symptoms and quality of life in patients with angina 1. The most effective approach to managing INOCA and MINOCA involves a personalized treatment plan based on the underlying mechanisms identified through comprehensive diagnostic evaluation.
From the Research
Definition of INOCA and MINOCA
- INOCA (Ischemia with No Obstructive Coronary Artery disease) is defined as patients with angiographic evidence of ischemia but no obstructive coronary artery disease (CAD) at coronary angiography 2, 3.
- MINOCA (Myocardial Infarction with No Obstructive Coronary Artery disease) is defined by the evidence of spontaneous acute myocardial infarction (MI) and angiographic exclusion of coronary stenoses ≥50% in any potential infarct-related artery, after having ruled out other clinically overt causes for the acute presentation 4, 5.
Characteristics of INOCA and MINOCA
- INOCA is estimated to be prevalent in 3-4 million individuals with a female predominance 3.
- MINOCA accounts for 5-8% of acute coronary syndrome (ACS) presentations 5.
- The predominant pathophysiologic mechanisms of MINOCA include both coronary (epicardial vasospasm, coronary microvascular disorder, spontaneous coronary artery dissection, coronary thrombus/embolism) and noncoronary (Takotsubo cardiomyopathy, myocarditis) pathologies 5.
- INOCA is composed of different endotypes including: microvascular dysfunction, vasospasm, and a combination of the two 3.
Diagnosis and Management of INOCA and MINOCA
- Diagnosis of INOCA requires either non-invasive or invasive techniques aimed at assessing coronary flow reserve (CFR), Index of Microcirculatory Resistance (IMR), and spasm secondary to acetylcholine injection 3.
- Treatment of INOCA remains elusive with current therapeutics tailored towards the specific endotype and ongoing clinical trials looking to assess the efficacy of traditional CAD medications 3.
- Management of MINOCA involves a comprehensive diagnostic evaluation and a high index of suspicion for early recognition and successful management 5.