Hypothermic Myocardial Preservation: The Freezing Debate

Area of Science:

• Cardiology
• Transplantation Medicine
• Cryobiology

Background:

• Heart preservation for transplantation is crucial.
• Ice storage (0°C) may cause graft dysfunction due to freeze injury.
• Investigating myocardial damage at different storage temperatures is necessary.

Purpose of the Study:

• To assess myocardial damage and function in rat hearts stored at 0°C, 4°C, and 8°C for 4 hours.
• To determine if 0°C storage causes freeze injury.
• To compare graft function after storage at different temperatures.

Main Methods:

• Rat hearts were stored in University of Wisconsin solution at 0°C, 4°C, or 8°C for 4 hours.
• Hearts were re-perfused and functional parameters (left ventricle pressure) were measured.
• Infarct size, ultrastructural, and biochemical changes were analyzed.

Main Results:

• No freeze injury was observed in hearts stored at 0°C via histologic or biochemical analysis.
• Infarct size was similar between hearts stored at 0°C and 4°C.
• Cardiac troponin I levels and left ventricle developed pressure were comparable across all storage groups (0°C, 4°C, 8°C).

Conclusions:

• Storage of hearts at 0°C for 4 hours does not induce freeze injury.
• Heart function is preserved similarly at 0°C, 4°C, and 8°C after 4-hour storage.
• 0°C appears to be a safe temperature for short-term heart preservation without compromising graft function.