Cytotoxicity of cardioplegic solutions: evaluation by tissue culture

Numerous cardioplegic solutions have been proposed for myocardial protection during open heart surgery. Their effectiveness has been evaluated by hemodynamic, enzymatic and histologic studies, but the cytotoxicity of these solutions has never been assessed. Human fibroblasts and endothelial cells in tissue culture were incubated for 3 hours at 19 degrees C in 12 of the most commonly used cardioplegic solutions. The solutions were then removed and replaced by tissue culture medium at 37 degrees C. The cytotoxicity of the solution was evaluated by staining the cells with trypan blue after 3 hours and 24 hours. The percentage of dead cells varied from 2--21%. Temperature and addition of blood to the various solutions significantly influenced cytotoxicity. Cardioplegic solutions appear to have different toxicity levels when tested in tissue culture.