Abstract 17780: Does Prolonged Post-mortem Cold Ischemic Harvest Time Influence Cryopreserved Pulmonary Allograft Tissue Integrity?
BACKGROUND: Cryopreserved pulmonary allografts (CPAs) remain the “ideal” conduit for reconstruction of the right ventricular outflow tract. This study investigated CPA structural integrity after prolonged cold ischemic harvest times in the juvenile sheep model.
MATERIAL/METHODS: Three groups with different post-mortem cold ischemic harvest times were studied. Group 1 (24h, n=10); Group 2 (48h, n=10); Group 3 (72h, n=10). In each group, 5 CPAs were studied in vitro after processing and thawing, and the other 5 CPAs were implanted in juvenile sheep for a minimum of 150 days.
Tensile strength tests (TS), Young’s Modulus (YM), Thermal Denaturation (Td), histological evaluation (H&E), scanning electron microscopy (SEM) and microbiological examinations were performed on all samples.
In the implant groups serology samples were obtained and echocardiography was performed before euthanasia. In addition von Kossa, Picoserius red, α-actin, immunohistochemistry (vWF, CD4, CD31 and CD34) and calcium content analyses were performed on the explanted CPAs.
RESULTS: The in vitro and in vivo studies failed to demonstrate any decrease in TS, YM and Td results. These results were also similar and constant between all CPAs in both the in vitro and in vivo groups.
SEM demonstrated a reduction of endothelial cells (50% at 24h, 60.9% at 48h and 40.9% at 72h), but H&E could not demonstrate autolysis in any CPA in vitro. All cultures were negative.
There were no differences in highly sensitive CRP and IgG. Echocardiography demonstrated normal function in all groups. Tissue integrity was confirmed by H&E and Picoserius red staining. Interstitial cells (α-actin) were present in 3/5 CPAs of Group 1, 1/5 CPAs of Group 2 and 3/5 CPAs of Group 3. Leaflet calcification was found in one CPA in Group 3. A monolayer of endothelial cells in all explanted valves was confirmed by vWF, CD31 and CD34 staning. CD4-positive cells were absent. SEM demonstrated confluence of endothelium of 88% in Group 1 and 60% in Groups 2 and 3. No statistical difference could be demonstrated in calcium content between explanted pulmonary leaflets.
CONCLUSION: This experimental study supports the concept of prolonged cold ischemic harvesting time of cryopreserved allograft to reduce allograft shortage.
- © 2013 by American Heart Association, Inc.