Comparison of Functional and Metabolic Assessments in Preservation Techniques for Heart Transplantation

Abstract

The present study compares simple hypothermic storage and hypothermic perfusion in a swine model of heart transplantation using metabolic and functional assessments. In both groups the hearts were initially protected with iso-osmolar potassium Tyers cardioplegia. The donor hearts of group A were placed in simple hypothermic storage for 5 h. The donor hearts of group B were placed onto a perfusion apparatus for 5 h with perfusion pressure maintained at 28 cm of H₂O and a myocardial temperature of 8–10 °C. The perfustate consisted of Tyers' solution with the addition of 2 mg/L of mannitol, 12.5 mg/L of glucose, 5 units/L of insulin, and 95% oxygen. The ischemic interval within both groups was 6 h, including orthotoipic transplantation. Investigation was conducted at three time periods: prepreservation (T₁) in the donor, and postpreservation (T₂) and immediately after loading (T₃) in the recipient. Following volume loading for the hypothermic perfusion group there was significant improvement of myocardial function (cardiac index, p <. 05; stroke index, p <. 05) with no significant change in systemic vascular resistance, systemic blood pressure, and heart rate. There was also significant improvement in myocardial performance (p <. 05) for the hypothermic perfusion group following volume loading. Results of fatty acid turnover using 15-p-iodo (¹²³I)-phenylpentodecanoic acid indicate significantly greater increase in metabolic rale for the perfusion group than for the hypothermic storage group, (p <. 05) This indicates improved metabolic status of the heart treated with the hypothermic perfusion technique. We conclude that a combination of functional and metabolic assessments is a good method for deduction of ischemic-reperfusion injury. He also conclude that hypothermic perfusion is superior to hypothermic storage for in vitro preservation of hearts for heart transplantation.

Key Words:

• Preservation techniques
• heart transplantation
• hypothermic storage
• hypothermic perfusion