Related Experiment Video
Updated: Jan 31, 2026
Rodent Working Heart Model for the Study of Myocardial Performance and Oxygen Consumption
Published on: August 16, 2016
Cardiovascular risk is associated with a transmural gradient of myocardial oxygenation during adenosine infusion
Judy M Luu1, Anna Schmidt2, Jacqueline Flewitt2
1Division of Cardiology, Department of Medicine, University of Manitoba, 409 Tache Avenue, Winnipeg, Manitoba, Canada.
Insights
Oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) reveals transmural oxygenation gradients in patients with coronary artery disease (CAD) and those at risk. This gradient, even without overt CAD, may serve as a non-invasive marker for cardiovascular risk.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- Coronary artery disease (CAD) often presents with transmural gradients in myocardial perfusion, particularly affecting the subendocardial layer.
- Oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) enables in vivo monitoring of myocardial oxygenation changes across the transmural depth.
Purpose of the Study:
- To investigate the hypothesis that OS-CMR can identify a transmural oxygenation gradient as a disease marker in patients at risk for CAD.
- To assess the utility of OS-CMR in detecting myocardial oxygenation abnormalities in patients with known CAD and those with cardiovascular risk factors.
Main Methods:
- 34 patients with CAD, 28 subjects with coronary risk factors, and 11 healthy volunteers were assessed using OS-CMR at 1.5 T.
- A T2*-weighted cine steady-state free precession sequence was applied at baseline and during adenosine infusion.
- Relative changes in myocardial oxygenation (ΔSI%) were quantified in the entire myocardium, subepicardial, and subendocardial layers, blinded to patient data.
Main Results:
- Healthy subjects exhibited homogenous signal intensity (SI) changes, while both patient groups showed significantly reduced ΔSI% in the subendocardial layer compared to the subepicardial layer.
- Both patient groups displayed an overall decreased ΔSI% across all myocardial layers compared to healthy subjects (P < 0.05).
- A transmural gradient of myocardial oxygenation response to adenosine was observed even in subjects with risk factors but no overt CAD.
Conclusions:
- Cardiovascular risk factors, even without overt CAD, are associated with a transmural gradient in myocardial oxygenation response to adenosine, detectable by OS-CMR.
- An inducible transmural oxygenation gradient identified by OS-CMR may function as a non-invasive biomarker for cardiovascular risk assessment.
Aims:
In patients with coronary artery disease (CAD), a transmural gradient of myocardial perfusion has been repeatedly observed, with the subendocardial layer showing more pronounced perfusion deficits. Oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) allows for monitoring transmural changes of myocardial oxygenation in vivo. We hypothesized that OS-CMR could help identify a transmural oxygenation gradient as a disease marker in patients at risk for CAD.
Methods And Results:
We assessed 34 patients with known CAD and 28 subjects with coronary risk factors but no evidence of significant CAD. Results were compared with 11 healthy volunteers. OS-CMR was performed at 1.5 T, applying a T2*-weighted cine steady state free precession sequence at baseline and during infusion of adenosine. A reader blinded to patient data quantified the relative change of myocardial oxygenation in OS-CMR, defined by the change of signal intensity (ΔSI%) between baseline and during adenosine infusion in the entire myocardium, the subepicardial layer, and the subendocardial layer. SI changes were homogenous throughout the myocardium in healthy subjects, whereas both, patients with risk factors only and patients with CAD, had a significantly smaller ΔSI% in the subendocardial layer than in the subendocardial layer. Both patient groups had an overall decreased ΔSI% across all layers when compared with healthy subjects (P < 0.05).
Conclusion:
Even in the absence of overt CAD, cardiovascular risk factors are associated with a transmural gradient of the myocardial oxygenation response to adenosine as assessed by OS-CMR. An inducible transmural oxygenation gradient may serve as a non-invasive marker for cardiovascular risk.
Related Concept Videos
01:26What is an Electrochemical Gradient?
The chemical gradient relies on differences in the abundance of a substance on the outside versus the inside of a cell and flows from areas of high to low ion concentration. In contrast, the electrical gradient revolves around an...
01:12Relative Risk
01:14Overview of the Cardiovascular System
Heart
The heart is the central pump of the cardiovascular system that circulates blood throughout the body. It comprises two atria receiving the blood and two ventricles pumping blood out of the heart. Their rhythmic contractions, called heartbeats, ensure that blood flow remains continuous.
Blood Vessels
Blood...
01:27Regulation of the Cardiovascular System
The regulation of the cardiovascular system involves the autonomic nervous system (ANS), baroreceptors, and chemoreceptors, ensuring that heart rate and blood pressure are appropriately modulated in response to varying physiological demands.
The ANS comprises two main divisions: the sympathetic and parasympathetic nervous systems. The sympathetic nervous system enhances...
01:26Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
01:27Energy Line and Hydraulic Gradient Line