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Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
Vascular endothelial dysfunction is associated with reversible myocardial perfusion defects in the absence of
Prem Soman1, Devang M Dave, James E Udelson
1Division of Cardiology, Tufts-New England Medical Center, Boston, Mass, USA. somanp@upmc.edu.
Insights
Endothelial dysfunction, not obstructive coronary artery disease, predicts abnormal myocardial perfusion imaging (MPI) in patients with chest pain. This suggests vascular pathology, not false positives, may cause these MPI defects.
Area of Science:
- Cardiology
- Vascular Biology
- Diagnostic Imaging
Background:
- Abnormal myocardial perfusion imaging (MPI) in patients without obstructive coronary artery disease (CAD) is poorly understood.
- Reversible MPI defects in non-obstructive CAD may indicate underlying vascular pathology or be false positives.
- Coronary endothelial dysfunction is a potential contributor to these MPI abnormalities.
Purpose of the Study:
- To investigate the role of endothelial dysfunction in abnormal MPI findings among patients without obstructive CAD.
- To determine if reversible MPI defects in the absence of obstructive CAD are linked to vascular pathology.
Main Methods:
- Prospective study of 36 patients with chest discomfort and reversible MPI defects but non-obstructive CAD.
- Control group (n=55) with chest discomfort and normal MPI.
- Assessment of brachial artery flow-mediated dilation (FMD) via ultrasound to evaluate endothelial function.
Main Results:
- Patients with abnormal MPI and non-obstructive CAD showed significantly lower FMD (9.0% ± 7.2%) compared to controls (12% ± 5.2%) (P = .03).
- Endothelial dysfunction, indicated by reduced FMD, was identified in patients with abnormal MPI.
- Endothelium-independent vasodilation and brachial artery size were similar between groups.
- Multivariate analysis revealed endothelial dysfunction as the sole predictor of reversible MPI defects.
Conclusions:
- Patients with chest pain, reversible MPI defects, and no obstructive CAD exhibit impaired endothelial function (lower FMD).
- Findings suggest a potential causal link between endothelial dysfunction and reversible MPI defects in this population.
- Further research is warranted to explore the relationship between endothelial dysfunction and MPI findings.
Background:
The purpose of this study was to investigate whether endothelial dysfunction contributes to abnormal myocardial perfusion imaging (MPI) observed in patients without obstructive coronary artery disease (CAD). It is unclear whether reversible MPI defects detected in the absence of obstructive CAD represent underlying vascular pathology or are false-positive MPI results. Recent evidence suggests that coronary endothelial dysfunction might play a role in the pathogenesis of these defects.
Methods And Results:
We prospectively recruited 36 patients with chest discomfort, reversible abnormalities on MPI, and nonobstructive or absent CAD (stenosis <50% on coronary angiography). The control group (n = 55) consisted of patients with chest discomfort and similar cardiac risk factors but with normal MPI findings. Vascular endothelial function was assessed in the brachial artery by ultrasound as the response to hyperemia and reported as percent flow-mediated dilation (FMD). Response to sublingual nitroglycerin was used as an indicator of endothelium-independent vasodilation. The patients with abnormal MPI findings and nonobstructive CAD had a significantly lower FMD (9.0% +/- 7.2%), indicating endothelial dysfunction, compared with those with similar risk factors and normal MPI findings (12% +/- 5.2%) (P = .03). Baseline brachial artery size and endothelium-independent dilation were similar between groups. On multivariate analysis, only endothelial dysfunction was predictive of reversible MPI defects.
Conclusions:
Patients with chest pain and reversible MPI defects but without obstructive CAD have lower FMD indicative of endothelial dysfunction, as compared with similar patients with normal MPI findings. The possibility of a causal link between reversible MPI defects and endothelial dysfunction needs further exploration.
