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Inflammation and microvascular dysfunction in cardiac syndrome X patients without conventional risk factors for
Alejandro Recio-Mayoral1, Ornella E Rimoldi, Paolo G Camici
1Medical Research Council Clinical Sciences Centre and National Heart and Lung Institute, Imperial College School of Medicine, London, United Kingdom.
Insights
Inflammation, indicated by elevated C-reactive protein (CRP), is linked to coronary microvascular dysfunction (CMD) in cardiac syndrome X (CSX). Higher CRP levels correlate with reduced coronary flow reserve (CFR) in CSX patients.
Area of Science:
- Cardiology
- Vascular Biology
- Inflammation Research
Background:
- Cardiac Syndrome X (CSX) is characterized by angina and ischemia despite normal coronary arteries.
- Coronary microvascular dysfunction (CMD) is a potential cause of CSX.
- Inflammation is hypothesized to contribute to myocardial ischemia in CSX.
Purpose of the Study:
- To investigate the relationship between coronary microvascular dysfunction (CMD) and inflammation in patients with Cardiac Syndrome X (CSX).
- To determine if inflammatory markers correlate with the severity of microvascular impairment in CSX.
Main Methods:
- Assessed 21 CSX patients and 21 controls using positron emission tomography to measure myocardial blood flow (MBF) and coronary flow reserve (CFR).
- Measured high-sensitivity C-reactive protein (CRP) to quantify inflammation.
- Subdivided patients based on CRP levels (≤3 mg/l vs. >3 mg/l).
Main Results:
- CSX patients showed a mildly reduced coronary flow reserve (CFR) compared to controls.
- Patients with CRP >3 mg/l exhibited significantly more impaired CFR and ischemic ECG changes.
- A negative correlation was found between CRP levels and CFR in CSX patients (r = -0.49, p = 0.02).
Conclusions:
- Elevated CRP levels in CSX patients are associated with significantly reduced CFR, indicating CMD.
- Inflammation appears to play a role in modulating coronary microvascular responses in CSX.
Objectives:
The aim of this study was to ascertain whether coronary microvascular dysfunction (CMD) and inflammation are related in cardiac syndrome X (CSX).
Background:
CMD can lead to CSX, defined as typical angina and transient myocardial ischemia despite normal coronary arteriograms. Inflammation has been suggested to play a role in the pathogenesis of myocardial ischemia in CSX.
Methods:
We assessed 21 CSX patients (age 52 ± 10 years; 17 women) without traditional cardiovascular risk factors and 21 matched apparently healthy control subjects. Positron emission tomography was used to measure myocardial blood flow (MBF) and coronary flow reserve (CFR) in response to intravenous adenosine, whereas high-sensitivity C-reactive protein (CRP) was measured to assess inflammation. Patients were subdivided a priori into 2 groups according to CRP concentrations at study entry (i.e., ≤3 or >3 mg/l).
Results:
There were no differences in resting (1.20 ± 0.23 ml/min/g vs. 1.14 ± 0.20 ml/min/g; p = 0.32) or hyperemic MBF (3.28 ± 1.02 ml/min/g vs. 3.68 ± 0.89 ml/min/g; p = 0.18) between CSX patients and the control group, whereas CFR was mildly reduced in CSX patients compared with the control group (2.77 ± 0.80 vs. 3.38 ± 0.80; p = 0.02). Patients with CRP >3 mg/l had more severe impairment of CFR (2.14 ± 0.33 vs. 3.16 ± 0.76; p = 0.001) and more ischemic electrocardiographic changes during adenosine administration than patients with lower CRP, and a negative correlation between CRP levels and CFR (r = -0.49, p = 0.02) was found in CSX patients.
Conclusions:
CSX patients with elevated CRP levels had a significantly reduced CFR compared with the control group, which is indicative of CMD. Our study thus suggests a role for inflammation in the modulation of coronary microvascular responses in patients with CSX.
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