Background: During free internal mammary artery grafting, cardioplegia administration can be performed through the internal mammary artery. The present study examined whether cardioplegic solutions produce arterial graft constriction and functional endothelial damage.
Methods: Forty internal mammary artery segments from 10 patients were incubated in Krebs solution (n=10), University of Wisconsin solution (n=10), Broussais Hospital solution (n=10), or blood cardioplegia (n=10).
Results: There was a significant difference in sensitivity to norepinephrine between segments in Krebs solution and those in University of Wisconsin solution or Broussais Hospital solution but not segments in blood cardioplegia. There was a significant difference in relaxation to acetylcholine between segments in Krebs solution and those in the three other cardioplegic solutions and between those in blood cardioplegia and segments in University of Wisconsin solution or Broussais Hospital solution. There was no significant difference in relaxation to sodium nitroprusside between segments in any of the solutions.
Conclusions: These experiments suggest that storage in the different cardioplegic solutions studied does not preserve the initial vasoreactivity of the internal mammary artery. However, blood cardioplegia appears to be less deleterious in regard to endothelial and myogenic vascular function.