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Reduction in reperfusion injury by blood-free reperfusion after experimental myocardial infarction
G L Schaer1, S P Karas, E C Santoian
1Division of Cardiology, Georgetown University Medical Center, Washington, D.C.
Insights
A novel blood-free reperfusion strategy using oxygenated perfluorochemicals significantly reduced myocardial reperfusion injury in dogs. This approach offers a promising method to mitigate heart attack damage by limiting blood-constituent-induced injury.
Area of Science:
- Cardiovascular Research
- Ischemia-Reperfusion Injury
- Myocardial Infarction
Background:
- Myocardial reperfusion injury is a significant complication following acute myocardial infarction.
- Blood constituents are implicated as contributors to reperfusion injury.
- Current therapeutic strategies aim to limit infarct size and preserve cardiac function.
Purpose of the Study:
- To evaluate the efficacy of transient, blood-free reperfusion using an oxygenated perfluorochemical emulsion in reducing myocardial reperfusion injury.
- To assess the impact of this intervention on infarct size and left ventricular function in a canine model.
Main Methods:
- A canine model of myocardial infarction was established using 90-minute left anterior descending coronary artery occlusion.
- The treated group received 15-minute reperfusion with acellular oxygenated perfluorochemical (Fluosol) before blood reperfusion.
- The control group underwent immediate blood reperfusion after occlusion.
- Infarct size and area at risk were quantified using histological and dye-staining methods.
- Left ventricular function was assessed via contrast ventriculography one week post-reperfusion.
Main Results:
- No significant differences were observed in major determinants of infarct size (rate-pressure product, area at risk, ischemia severity) between groups.
- The treated group showed a 47% reduction in infarct size relative to the area at risk (27.0% vs. 50.8%, p<0.01).
- Treated dogs exhibited improved global (57.5% vs. 51.0%, p<0.05) and regional (32.6% vs. 19.8%, p<0.05) ejection fractions one week after reperfusion.
Conclusions:
- Transient blood-free reperfusion with oxygenated perfluorochemicals effectively reduces myocardial reperfusion injury in a canine model.
- This strategy mitigates infarct expansion and preserves cardiac function.
- The findings suggest a potential therapeutic benefit of acellular oxygenated emulsions in managing myocardial infarction.
Abstract:
Because myocardial reperfusion injury may be caused by various blood constituents, a transient period of blood-free reperfusion was evaluated in closed chest dogs subjected to a 90 min angioplasty balloon occlusion of the left anterior descending coronary artery. In the treated group (n = 13), the balloon remained inflated for an additional 15 min while the infarct vessel was perfused with an acellular oxygenated perfluorochemical emulsion (Fluosol). The balloon was then deflated, permitting blood reperfusion. In the control group (n = 13), the balloon was deflated after 90 min of coronary occlusion. One week after infarction, the area at risk was defined in vivo by monastral blue dye staining, and the area of myocardial necrosis was assessed using triphenyltetrazolium chloride staining with histologic confirmation. Major determinants of infarct size, including rate-pressure product, area at risk and severity of myocardial ischemia (assessed by the extent of ST segment elevation during coronary occlusion), were not significantly different in the two groups. Treated dogs demonstrated a 47% reduction in infarct size expressed as a percent of the area at risk compared with control dogs (27.0 +/- 4.4% versus 50.8 +/- 4.4%, p less than 0.01). Treated dogs also demonstrated a superior global left ventricular ejection fraction (57.5 +/- 2.5% versus 51.0 +/- 2.2%, p less than 0.05) and anterolateral (regional) ejection fraction (32.6 +/- 3.6% versus 19.8 +/- 3.9%, p less than 0.05) compared with values in control dogs assessed by contrast ventriculography after 1 week of reperfusion. It is concluded that a transient period of blood-free reperfusion with an oxygenated perfluorochemical reduces reperfusion injury in a canine model of myocardial infarction.