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Updated: Jul 2, 2025
Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction
Published on: October 14, 2016
Advanced technique of myocardial no-reflow quantification using indocyanine green
Dmitry Sonin1,2, Garry Papayan1,2, Maria Istomina1,3
1Institute of Experimental Medicine, Almazov National Medical Research Centre, 2 Akkuratova Str., 197341 Saint Petersburg, Russia.
Insights
Indocyanine green (ICG) can visualize myocardial no-reflow zones after ischemia-reperfusion injury. This novel method accurately identifies no-reflow areas, offering an alternative to traditional techniques.
Area of Science:
- Cardiovascular Research
- Experimental Myocardial Infarction Models
- Microvascular Physiology
Background:
- The no-reflow phenomenon, characterized by impaired blood flow post-reperfusion, affects over half of patients undergoing primary percutaneous coronary intervention (PCI).
- Current methods for assessing no-reflow, such as thioflavin S (ThS) staining, primarily estimate microvascular obstruction size.
Purpose of the Study:
- To investigate the potential of indocyanine green (ICG) for visualizing no-reflow zones in a rat model of myocardial ischemia-reperfusion injury.
- To evaluate ICG's ability to assess both microvascular obstruction and vascular permeability in myocardial infarction zones.
Main Methods:
- Utilized dual staining with ICG and ThS in a rat myocardium ischemia-reperfusion model.
- Employed a FLUM multispectral fluorescence organoscope for simultaneous fluorescence recording.
- Correlated ICG fluorescence patterns with ThS-identified no-reflow zones.
Main Results:
- Identified ICG-negative zones that directly correlated in size with ThS-detected no-reflow areas.
- Demonstrated that contrast changes between no-reflow and healthy myocardium reflect the severity of blood stasis.
- Confirmed ICG-negative zones represent no-reflow regions.
Conclusions:
- Indocyanine green (ICG) effectively visualizes no-reflow zones in experimental myocardial infarction.
- The ICG method provides a viable alternative or adjunct to traditional ThS staining for assessing no-reflow.
- ICG's retention in tissues with increased vascular permeability aids in evaluating infarction severity.
Abstract:
The post-ischemic no-reflow phenomenon after primary percutaneous coronary intervention (PCI) is observed in more than half of subjects and is defined as the absence or marked slowing of distal coronary blood flow despite removal of the arterial occlusion. To visualize no-reflow in experimental studies, the fluorescent dye thioflavin S (ThS) is often used, which allows for the estimation of the size of microvascular obstruction by staining the endothelial lining of vessels. Based on the ability of indocyanine green (ICG) to be retained in tissues with increased vascular permeability, we proposed the possibility of using it to assess not only the severity of microvascular obstruction but also the degree of vascular permeability in the zone of myocardial infarction. The aim of our study was to investigate the possibility of using ICG to visualize no-reflow zones after ischemia-reperfusion injury of rat myocardium. Using dual ICG and ThS staining and the FLUM multispectral fluorescence organoscope, we recorded ICG and ThS fluorescence within the zone of myocardial necrosis, identifying ICG-negative zones whose size correlated with the size of the no-reflow zones detected by ThS. It is also shown that the contrast change between the no-reflow zone and nonischemic myocardium reflects the severity of blood stasis, indicating that ICG-negative zones are no-reflow zones. The described method can be an addition or alternative to the traditional method of measuring the size of no-reflow zones in the experiment.
