Coronary microvascular dysfunction in patients with stable coronary artery disease: The CE-MARC 2 coronary physiology
David Corcoran1, Robin Young2, David Adlam3
1British Heart Foundation (BHF) Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, Scotland, UK; West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Glasgow, Scotland, UK.
Insights
Coronary microvascular dysfunction is prevalent in patients experiencing angina, irrespective of obstructive coronary artery disease. Invasive assessment of microvascular function aids clinical decision-making for these patients.
Area of Science:
- Cardiology
- Vascular Medicine
- Diagnostic Imaging
Background:
- No obstructive coronary artery disease (NOCAD) is frequently observed in patients with angina undergoing invasive management.
- Persistent angina post-percutaneous coronary intervention (PCI) suggests potential underlying coronary microvascular dysfunction.
- Assessing the prevalence of coronary microvascular dysfunction in patients with suspected coronary artery disease (CAD) is crucial.
Purpose of the Study:
- To determine the proportion of patients with suspected CAD who exhibit coronary microvascular dysfunction.
- To investigate the role of microvascular function assessment in patients with and without obstructive epicardial CAD.
Main Methods:
- Prospective multicenter randomized controlled trial (CE-MARC 2) involving functional imaging versus guideline-based management.
- Invasive coronary angiography with protocol-directed fractional flow reserve (FFR) measurements.
- Assessment of microvascular function parameters including coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and resistance reserve ratio (RRR) in epicardial coronary arteries.
Main Results:
- Of 63 patients with microvascular function assessed, 40% (25/63) had NOCAD, and 68% of these showed abnormal microvascular function.
- Obstructive epicardial CAD was present in 60% (38/63) of patients, with significant proportions exhibiting abnormal IMR (39%), CFR (53%), and RRR (32%).
- Abnormalities in IMR, CFR, and RRR were common in both NOCAD and obstructive epicardial CAD groups.
Conclusions:
- Coronary microvascular dysfunction is a common finding in patients presenting with angina.
- Invasive assessment of microvascular function provides valuable insights for managing patients with both NOCAD and obstructive epicardial CAD.
- Microvascular function assessment may guide treatment decisions and improve outcomes in patients with angina.
Background:
In patients with angina undergoing invasive management, no obstructive coronary artery disease (NOCAD) is a common finding, and angina may persist following percutaneous coronary intervention (PCI). Coronary microvascular dysfunction may be relevant. We aimed to assess the proportion of patients presenting with suspected CAD who had coronary microvascular dysfunction.
Methods:
Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease 2 (CE-MARC 2) was a prospective multicenter randomised controlled trial of functional imaging versus guideline-based management in patients with suspected CAD. Invasive coronary angiography was protocol-directed. Fractional flow reserve (FFR) and parameters of microvascular function (coronary flow reserve (CFR), index of microcirculatory resistance (IMR), resistance reserve ratio (RRR)) were measured in major epicardial coronary arteries with ≥40-≤90% diameter stenosis. An FFR value ≤0.80 indicated the presence of obstructive CAD.
Results:
267/1202 (22.2%) patients underwent angiography and 81 (30%) patients had FFR measured. 63 (78%) of these patients had microvascular function assessed in 85 arteries (mean age 58.5 ± 8.2 years; 47 (75%) male). 25/63 (40%) patients had NOCAD, and of these, 17 (68%) had an abnormality ≥1 parameter of microvascular function (abnormal IMR (≥25), abnormal CFR (<2.0), and abnormal RRR (<2.0) occurred in 10 (40%), 12 (48%), and 11 (44%), respectively). 38/63 (60%) patients had obstructive epicardial CAD. Of these patients, 15/38 (39%), 20/38 (53%), and 12/38 (32%) had an abnormal IMR, CFR and RRR, respectively.
Conclusions:
Coronary microvascular dysfunction is common in patients with angina. Invasive assessment of microvascular function may be informative and relevant for decision-making in patients with both NOCAD and obstructive epicardial CAD.
Clinical Trial Registration:
ClinicalTrials.gov Identifier: NCT01664858.
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