A novel surgical procedure: scaffold-pulmonary autograft transplantation

Mitral valve-related operations are easy to perform and show good results, but to prevent severe thromboembolism or a high ratio of prosthetic valve destruction by tissue, lifetime anticoagulant therapy is essential after the operation. Thus, identifying a new type of surgical procedure and prosthetic valve to cure mitral valve diseases is necessary. Pulmonary valve autograft transplantation (Ross II) with the "top hat" transplantation technique was first reported by Ross DN to cure mitral disease. Because the "top hat" procedure has some shortcomings, we designed the scaffold-pulmonary autograft transplantation procedure and performed animal experiments to confirm the feasibility and effectiveness of the procedure. A total of 13 minipigs, weighing 20-25 kg, were employed as experimental animals to undergo scaffold-pulmonary autograft valve transplantation in our surgical animal lab. The surgical procedure was performed under hypothermic general anaesthesia and extracorporeal circulation (or cardiopulmonary bypass, CPB). Briefly, the chest cave was opened through the left intercostal, the pulmonary valve autograft was harvested during on-pump beating heart, and the pulmonary valve autograft was mounted in a self-made pulmonary valve scaffold and transferred to the mitral valve annulus without removing the mitral instruments. Finally, the outflow tract of the right ventricle was re-established with a pig pulmonary homograft. After finishing data collection, all animals were executed 1 hour after removal from the CPB. For the 13 minipigs that underwent the operation, the CPB time was 182.4 ± 23.4 min. Two of the thirteen cases died of bleeding during the operation and of a post-operative pulmonary embolism, and the remaining eleven survived for one hour. The pressure of the left atrium did not increase significantly (P = 1.00), and the ultrasonic cardiograph (UCG) showed good function of the new mitral valves, with mean ejection fraction (EF) values of 63.6%. The mitral valve orifice areas were 1.10 ± 0.13 cm(2) (pre-operation) and 1.01 ± 0.08 cm(2) (post-operation) (P = 0.013). The function and structure of the new mitral valves were normal. We preliminarily consider scaffold-pulmonary autograft valve transplantation to be a new alternative to cure mitral valve disease, but advanced chronic animal experiments will be needed to confirm the long-term results of the operation. The results showed it could be a new alternative to cure mitral valve disease.