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Backtable heat-enhanced preconditioning: a simple and effective means of improving function of heart transplants
E Kevelaitis1, A P Patel, A Oubenaissa
1Department of Cardiovascular Surgery, Hĵpital Bichat, Paris, France.
Insights
A brief period of topical heating before cold storage significantly improves heart transplant recovery. This "backtable preconditioning" enhances functional recovery, offering a simple method to improve outcomes for donor hearts.
Area of Science:
- Cardiology
- Transplantation Biology
- Organ Preservation
Background:
- Cardiac transplant teams typically prioritize immediate cold storage of donor hearts.
- This study investigated the protective potential of a novel approach: heat-enhanced ischemic preconditioning before storage.
Purpose of the Study:
- To evaluate the efficacy of brief, topical heating of explanted donor hearts before cold storage.
- To determine if this
- backtable preconditioning
- improves functional recovery after transplantation.
Main Methods:
- Fifty-three isolated rat hearts were subjected to 4 hours of cold storage (4°C) in Celsior solution.
- Experimental groups received topical heating (22°C, 37°C, or 42.5°C) for 15 minutes prior to storage.
- Control hearts were immediately immersed in cold storage solution.
Main Results:
- Hearts heated to 37°C and 42.5°C showed significantly improved end-diastolic pressure and dP/dT during reperfusion compared to controls.
- No upregulation of HSP 72 was observed, suggesting a mechanism beyond heat shock protein induction.
- Inhibition of protein kinase C, tyrosine kinase, or mitochondrial K(ATP) channels abolished the protective effects at 42.5°C.
Conclusions:
- Brief postexplant ischemia with topical heating (
- backtable preconditioning
- ) is a simple and effective method.
- This technique can significantly improve the functional recovery of heart transplants.
Background:
Cardiac harvest teams are usually committed to immediately transfer the explanted donor heart into its cold storage solution. We tested the opposite hypothesis that a brief prestorage episode of heat-enhanced ischemic preconditioning could be protective.
Methods:
Fifty-three isolated isovolumic rat hearts underwent 4 hours of cold (4 degrees C) storage in the Celsior preservation solution and 2 hours of reperfusion. Control hearts were immediately immersed after arrest. In the 3 treated groups, 2 customized thermal probes were first applied onto the left ventricular free wall of the explanted heart at 22 degrees C, 37 degrees C or 42.5 degrees C for 15 minutes before immersion. Each of the selected temperatures were monitored at the probe-tissue interface by a thermocouple.
Results:
Whereas base line end-diastolic pressure was set at = 8 mm Hg in all groups, it increased during reperfusion (mean +/- SEM) to 28+/-3, 27+/-3, 17+/-1, and 18+/-2 mm Hg in control, 22 degrees C, 37 degrees C and 42.5 degrees C-heated hearts, respectively (37 degrees C and 42.5 degrees C: p < 0.05 versus controls and 22 degrees C). Slopes of pressure-volume curves featured similar patterns. Likewise, reperfusion dP/dT (mm Hg/s(-1)) was significantly lower in control and 22 degrees C hearts (1,119+/-114 and 1,076+/-125, respectively) than in those undergoing prestorage heating to 37 degrees C and 42.5 degrees C (1,545+/-109 and 1,719+/-111, p < 0.05 and p < 0.01 versus controls and 22 degrees C, respectively). Western blot analysis of LV samples did not demonstrate any upregulation of HSP 72 in either group. Conversely, the involvement of preconditioning was evidenced by the loss of protection in the 42.5 degrees C-heated hearts when, in 2 additional groups, the storage solution was supplemented with either the protein kinase C and tyrosine kinase inhibitors chelerythrine (5 micromol/L) and genistein (50 micromol/L) or the mitochondrial K(ATP) channel inhibitor 5-hydroxydecanoate (200 micromol/L).
Conclusions:
A brief period of postexplant ischemia with enhancement by topical heating ("backtable preconditioning") could be a simple and effective means of improving the functional recovery of heart transplants.