Intermittent reperfusion extends myocardial preservation for transplantation

Area of Science:

• Cardiology
• Cardiovascular Surgery
• Organ Preservation

Background:

• Prolonged hypothermic storage is standard for heart preservation.
• Optimizing preservation techniques is crucial for reducing ischemia-reperfusion injury.
• Assessing myocardial viability and function post-preservation is essential.

Purpose of the Study:

• To compare continuous hypothermic heart storage with intermittent reperfusion.
• To evaluate the impact of intermittent reperfusion on myocardial adenosine triphosphate (ATP) levels.
• To assess left ventricular (LV) function after different preservation protocols.

Main Methods:

• Canine hearts were subjected to prolonged hypothermic storage (7.5 hours) or intermittent reperfusion (3 hours ischemia, 1.5 hours reperfusion, 3 hours ischemia, 1.5 hours reperfusion).
• Left ventricular (LV) function was measured by peak systolic pressure and +dP/dtmax.
• Myocardial adenosine triphosphate (ATP) levels were assayed before ischemia and after rewarming periods.

Main Results:

• Intermittent reperfusion maintained higher myocardial ATP levels compared to continuous storage (79.7% vs. 57.9% of baseline, p < .03).
• Left ventricular function parameters (peak pressure, +dP/dtmax) were higher in the intermittent reperfusion group, though not statistically significant.
• One heart in the continuous storage group could not be defibrillated, while all in the intermittent group completed the protocol.

Conclusions:

• Intermittent reperfusion during hypothermic heart preservation appears to enhance myocardial protection.
• Reperfusion may allow for substrate repletion, improving myocardial energy status and potentially function.
• This strategy warrants further investigation for clinical application in organ transplantation.