Preservation of pediatric donor hearts via subnormothermic machine perfusion: Comparison to cold storage

Ex-situ heart perfusion (ESHP) improves donor heart preservation via provision of a semi-physiologic, controlled environment. Optimizing preservation capacity through ESHP is of great interest to expand the donor pool and overcome logistical challenges. However, devices are currently untailored to pediatric donor hearts. We sought to evaluate subnormothermic ESHP (sESPH) in comparison to static cold storage (SCS).

Juvenile Yorkshire pig hearts (∼20 kg) were procured and subject to 10 hours of sESHP (n = 6) or 6 hours of SCS in modified Del Nido solution (n = 5), then transplanted orthotopically into weight-matched recipients. Following 2 hours of reperfusion, echocardiography was conducted before pigs were euthanized and samples of the ventricles were collected for analysis. Immunofluorescence staining for vascular inflammation markers VCAM-1, ICAM-1, and E-selectin was conducted. Hematoxylin and eosin staining of the ventricles was conducted and reviewed by a pathologist blinded to the experimental groups and scored for contraction bands, edema formation, inflammation, and hemorrhage.

By echocardiography, hearts from both groups regained acceptable biventricular functionality, with no difference in left ventricular ejection fraction and shortening fraction between groups (p > 0.05). No differences in histological damage scores were found between groups (p > 0.05). Immunofluorescence staining showed qualitatively lessened expression of all markers in the sESPH group.

sESPH appears to prolong out-of-body time of pediatric donor hearts, with non-inferior tissue and functional preservation compared to SCS. sESHP may lessen inflammatory burden over the course of the preservation period.