Partial heart transplant valves demonstrate growth in piglets despite prolonged cold storage.

Background: Traditional heart valve replacement options lack growth potential, limiting their long-term effectiveness in pediatric patients. Partial heart transplantation (PHT) is an emerging approach that offers growth-capable valves by transplanting only the valve-containing segment of the heart. Here, we report on the effects of extended cold storage on the viability and growth potential of PHT grafts.

Methods: Pulmonary and aortic conduits were harvested from piglets and human donors and stored at 4°C in cold-storage solution, with some samples supplemented with apoptosis inhibitors, membrane stabilizers and antibiotics to optimize cellular viability. Viability was assessed in vitro over seven days using the MTS assay. A piglet model of pulmonary valve replacement was utilized to assess in vivo growth potential following one week of cold storage.

Results: In vitro analysis showed a gradual decline in metabolic activity over seven days, with approximately 50% viability retained in both porcine and human valves. Supplementation with apoptosis inhibitors and membrane stabilizers did not significantly enhance viability. In vivo, transplanted conduits demonstrated robust leaflet and annular growth without significant stenosis or regurgitation, confirming the maintenance of growth potential despite reduced viability.

Conclusions: PHT grafts can be preserved in cold storage for up to one week without significantly compromising in vivo growth potential. These findings support the feasibility of PHT as a viable growth-capable valve replacement option for children and suggest that optimized cold storage protocols could facilitate broader access to this technique.