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Symptom phenotypes and coronary microvascular function in non-obstructive coronary artery disease: Insights beyond
Kotaro Matsumoto1, Kenichiro Otsuka1, Shunsuke Kagawa1
1Department of Cardiovascular Medicine, Osaka Metropolitan University Graduate School of Medicine, 1-4-3 Asahicho, Abenoku, Osaka, 545-8585, Japan.
Insights
Coronary microvascular dysfunction (CMD) varies with chest pain symptoms in non-obstructive coronary artery disease (NOCA). Objective physiological testing is crucial for accurate CMD assessment, as symptoms alone are unreliable.
Area of Science:
- Cardiology
- Vascular Medicine
- Diagnostic Imaging
Background:
- Non-obstructive coronary artery disease (NOCA) affects a significant patient population.
- Coronary microvascular dysfunction (CMD) is increasingly recognized as a cause of angina in NOCA.
- Current diagnostic approaches often rely on symptom presentation, which may not accurately reflect underlying physiology.
Purpose of the Study:
- To investigate the relationship between coronary microvascular dysfunction (CMD) indices and chest pain presentation in patients with NOCA.
- To assess the diagnostic performance of symptom-based evaluation for detecting CMD.
- To determine if objective physiological measures correlate with symptom severity in NOCA patients.
Main Methods:
- Retrospective observational study of 59 patients with intermediate LAD stenosis and preserved FFR.
- Invasive assessment of coronary microvascular function using coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and myocardial resistance reserve (MRR).
- Analysis of associations between symptom phenotypes (typical angina, atypical, asymptomatic) and physiological indices.
Main Results:
- Coronary flow reserve (CFR) and myocardial resistance reserve (MRR) significantly differed across symptom phenotypes (p < 0.001), with typical angina patients showing the lowest values.
- Index of microcirculatory resistance (IMR) did not differ significantly between groups.
- Symptom severity inversely correlated with CFR and MRR (p < 0.005), and symptom-based assessment demonstrated higher specificity than sensitivity for CMD detection.
Conclusions:
- Coronary microvascular vasodilatory reserve varies significantly based on symptom presentation in NOCA patients.
- Symptom assessment alone is unreliable for diagnosing CMD in NOCA.
- Objective physiological evaluation is essential for accurate characterization and management of CMD in NOCA.
Study Objective:
To examine the relationship between coronary microvascular dysfunction (CMD) indices and chest pain presentation in patients with non-obstructive coronary artery disease (NOCA).
Design And Setting:
Retrospective, single-center observational study.
Participants:
Patients with angiographically intermediate left anterior descending artery (LAD) stenosis and preserved epicardial physiology (fraction flow reserve, FFR >0.80), with no significant stenosis in vessels other than the LAD.
Interventions:
Invasive CMD assessment using coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and myocardial resistance reserve (MRR).
Main Outcome Measures:
Associations between symptom phenotypes and physiological indices, and the diagnostic performance of symptom-based assessment for detecting CMD.
Results:
Among 59 patients (mean age 69.2 years; 71 % male), CFR and MRR differed significantly across symptom phenotypes (both p < 0.001), whereas IMR did not. Patients with typical angina exhibited the lowest CFR and MRR, indicating impaired microvascular vasodilatory reserve despite preserved epicardial physiology. Conversely, patients with atypical symptoms had the highest CFR and MRR, whereas asymptomatic patients had intermediate values. FFR was comparable across groups (median 0.89, p = 0.21). In age-adjusted analyses, symptom severity was inversely associated with CFR (β = -1.085, p = 0.004) and MRR (β = -1.062, p = 0.003), but not with IMR. Symptom-based assessment showed higher specificity than sensitivity across CMD definitions and performed best for impaired MRR (sensitivity 60.9 %, specificity 80.6 %). Functional CMD was observed even in asymptomatic patients.
Conclusion:
In patients with NOCA, coronary microvascular vasodilatory reserve varies according to symptom phenotype, highlighting the limited reliability of symptom assessment alone and underscoring the importance of objective physiological evaluation for characterizing CMD.
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