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Coronary microvascular dysfunction and cardiovascular outcomes (Multicenter FLOW-CMD Registry): a prospective,
Joo Myung Lee1, Seung Hun Lee2, Dong Hyun Gim1
1Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Insights
Coronary microvascular dysfunction is common in patients undergoing angiography and significantly increases the risk of adverse cardiovascular events, including death and heart failure. Early identification is crucial for better patient outcomes.
Area of Science:
- Cardiology
- Vascular Medicine
- Diagnostic Imaging
Background:
- Coronary microvascular dysfunction (CMD) frequently coexists with epicardial coronary artery disease (CAD).
- Limited data exist on the prevalence and prognostic impact of CMD in patients undergoing invasive coronary angiography.
- This study evaluated CMD in routine practice during invasive coronary angiography.
Purpose of the Study:
- To determine the prevalence of coronary microvascular dysfunction in patients undergoing invasive coronary angiography.
- To assess the prognostic significance of coronary microvascular dysfunction in this patient population.
- To investigate the association between CMD and major adverse cardiovascular events.
Main Methods:
- Prospective, multicentre cohort study in South Korea involving 1003 patients undergoing invasive coronary angiography.
- Coronary physiological assessment used to define obstructive epicardial CAD and coronary microvascular dysfunction (CFR < 2.0 and/or IMR ≥ 25).
- Primary endpoint: composite of all-cause death, myocardial infarction, repeat revascularisation, or heart failure hospitalization over a median follow-up of 1.9 years.
Main Results:
- Coronary microvascular dysfunction was present in 21.5% of patients with obstructive epicardial CAD and 9.3% without.
- Patients with CMD had a significantly higher risk of the primary composite endpoint (HR 1.91; p=0.0047).
- The 2-year event rate was 18.8% for patients with CMD versus 10.5% for those with preserved microvascular function.
Conclusions:
- Coronary microvascular dysfunction is a common finding in patients undergoing invasive coronary angiography for suspected ischaemic heart disease.
- CMD is independently associated with an increased risk of major adverse cardiovascular events.
- These findings highlight the importance of assessing microvascular function in clinical practice.
Background:
Coronary microvascular dysfunction often coexists with epicardial coronary artery disease. Data regarding its prevalence and prognosis in patients undergoing invasive coronary angiography are scarce. This study aimed to evaluate the prevalence and prognosis of coronary microvascular dysfunction in patients undergoing clinically indicated invasive coronary angiography in routine practice.
Methods:
In this prospective, multicentre cohort study done in seven tertiary medical hospitals in South Korea, consecutive patients aged 18 years and older who were referred for clinically indicated invasive coronary angiography were systematically screened and evaluated by coronary physiological assessment. Obstructive epicardial coronary artery disease was defined as an intermediate stenosis (40-90% diameter stenosis), with fractional flow reserve of 0·80 or less or severe stenosis (>90% of diameter stenosis) treated with revascularisation without fractional flow reserve measurement. Coronary microvascular dysfunction was identified as coronary flow reserve below 2·0 and index of microcirculatory resistance of ≥25. The primary endpoint was a composite of all-cause death, myocardial infarction, clinically driven repeat revascularisation, or hospitalisation for heart failure. The Multicenter FLOW-CMD Registry study is registered with ClinicalTrials.gov (NCT05369182).
Findings:
Between April 22, 2022, and Nov 19, 2024, 5764 patients were screened and 1003 patients were enrolled (756 men and 247 women). Among these patients, coronary microvascular dysfunction was observed in 123 (21·5%) of 573 patients with obstructive epicardial coronary artery disease and in 40 (9·3%) of 430 patients without obstructive epicardial coronary artery disease. At a median follow-up of 1·9 years, the primary endpoint occurred in 26 patients (2-year Kaplan-Meier estimate 18·8%) with coronary microvascular dysfunction and 70 patients (2-year Kaplan-Meier estimate 10·5%) with preserved microvascular function (hazard ratio 1·91 [95% CI 1·22-2·99]; p=0·0047).
Interpretation:
In patients with suspected ischaemic heart disease undergoing invasive coronary angiography, coronary microvascular dysfunction coexisted with epicardial coronary artery disease and was associated with a higher risk of the composite of all-cause death, myocardial infarction, clinically driven repeat revascularisation, or hospitalisation for heart failure.
Funding:
Abbott Vascular and Boston Scientific.
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