Background: University of Wisconsin (intracellular) solution has been shown to offer some distinct benefits of myocardial preservation over Stanford (extracellular) solution, including a more rapid functional recovery, improved adenosine triphosphate preservation, and a tendency for less postoperative inotropic agents. However intracellular solutions with high potassium content have been reported to cause a functional if not structural endothelial injury in laboratory experiments.
Methods: Because of this information we retrospectively viewed our follow-up angiographic data for the development of the cardiac allograft vasculopathy in a consecutive series of 195 heart transplant recipients. These patients were treated in identical fashion, with the same immunosuppression regimen, except for the type of cardioplegia used--Stanford solution (group I n = 95) and University of Wisconsin solution (group II n = 100).
Results: With a mean follow-up of 24 months after transplantation, a significant difference was seen in the development of cardiac allograft vasculopathy in group II (22%) versus group I (14%, p < 0.03). Although significant differences were observed with univariate analysis with respect to donor age and ischemic time favoring group I and with multivariate statistical analysis with respect to overall rejections favoring group II, the only significant variable for the difference in the development of allograft vasculopathy was University of Wisconsin cardioplegic solution (p < 0.003). A subgroup of 30 patients previously randomized for a functional study comparing the two cardioplegic agents showed a tendency for statistical significance with a freedom from allograft vasculopathy of 93% in group I, as compared with 83% in group II, after 13 months follow-up (p = 0.09). The overall probability of being free of vasculopathy at 24 months was 86% for group I and 70% for group II.
Conclusions: The data support the conclusion that University of Wisconsin intracellular solution is associated with an increased incidence of vasculopathy versus Stanford solution and warrants investigation for modification of this preservation agent in heart transplantation.