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Updated: Sep 20, 2025
Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
[Coronary microvascular dysfunction: mechanisms and clinical outcome]
Ciro Indolfi1, Italo Porto2, Saverio Muscoli3
1Istituto di Cardiologia, Dipartimento di Scienze Mediche e Chirurgiche, Università degli Studi "Magna Graecia", Catanzaro.
Insights
Microvascular angina affects many patients without coronary artery blockages. Current treatments for microvascular dysfunction show limited success, necessitating further research into multifactorial mechanisms.
Area of Science:
- Cardiology
- Cardiovascular Research
- Microvascular Function
Background:
- A significant proportion of patients presenting with typical chest pain and undergoing coronary angiography lack obstructive coronary artery disease.
- Many of these patients exhibit microvascular myocardial disease, often co-occurring with conditions like left ventricular hypertrophy, cardiomyopathies, or valve disease.
Purpose of the Study:
- To detail the definition, underlying mechanisms, and diagnostic approaches for microvascular angina.
- To review the current understanding of microvascular dysfunction in patients without significant coronary stenosis.
Main Methods:
- Defining microvascular angina based on ischemic symptoms, absence of obstructive coronary artery disease, objective ischemia evidence, and pathological microcirculation indices.
- Utilizing intracoronary vasoreactivity tests to assess microcirculatory resistance and coronary flow reserve.
- Reviewing diagnostic tests for microvascular dysfunction.
Main Results:
- Microvascular angina is characterized by ischemic symptoms without significant coronary stenosis, confirmed by objective ischemia and impaired microcirculatory function.
- Diagnostic criteria include specific thresholds for index of microcirculatory resistance and coronary flow reserve.
- The multifactorial nature of microvascular dysfunction presents challenges in improving clinical outcomes.
Conclusions:
- Microvascular dysfunction plays a critical role in the prognosis of patients with chest pain and non-obstructive coronary artery disease.
- Current therapeutic strategies have yielded limited success, underscoring the complexity of the condition.
- Further research is essential to develop effective treatments for microvascular myocardial disease.
Abstract:
A large percentage of patients, predominantly female, who undergo coronary angiography for typical chest pain do not have significant coronary stenosis. Many of these patients with microvascular myocardial disease have left ventricular hypertrophy, cardiomyopathies, valve disease, or other clinical conditions. The definition of microvascular angina is based on (i) symptoms of myocardial ischemia, (ii) absence of obstructive coronary artery disease (<50% stenosis on coronary angiography or coronary computed tomography scan), (iii) objective evidence of myocardial ischemia (ischemic electrocardiographic abnormalities during episodes of chest pain and/or myocardial perfusion defects or regional contractility abnormalities), and (iv) pathological indices of microcirculation (index of microcirculatory resistance >25, coronary flow reserve <2.0) and/or microvascular spasm (TIMI flow <2) during intracoronary vasoreactivity tests. The basic mechanisms and the diagnostic tests of microvascular dysfunction are reported in detail.From a clinical standpoint, while the crucial role of microcirculation in determining short- and long-term prognosis is evident, efforts to date to improve clinical outcomes in patients with microvascular obstruction have had limited success, most likely because microvascular dysfunction is a multifactorial process with several interdependent underlying pathophysiological mechanisms. Therefore, further studies are needed to develop effective therapeutic strategies for microvascular myocardial disease.
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