Is internal thoracic artery resistant to reperfusion injury? Evaluation of the storage of free internal thoracic artery grafts.

OBJECTIVES

The in situ internal thoracic artery (ITA) is recognized as the best conduit for coronary artery bypass surgery. The ITA-if it is used as an in situ graft-has a much higher late patency rate than any other arterial graft, including a free ITA graft. We sought to determine if the use of the ITA as an in situ/free graft and its storage in preservation solutions, have an effect on endothelial function.

METHODS

The ITA was harvested as either a free or in situ graft in a porcine model. Free grafts were stored in different preservation solutions (saline, Custodiol and Tiprotec [both Köhler Chemie GmbH, Bensheim, Germany]). The ITA was anastomosed off pump to the left anterior descending artery (as in situ/free graft). Freshly harvested ITA served as a control. After 2 hours of reperfusion, the implanted grafts were harvested. The assessment of endothelial function, histopathological analysis, and gene expression were performed.

RESULTS

Endothelial function and integrity were severely impaired after reperfusion in the free ITA groups, however, it was partially preserved in the Tiprotec group. Reperfusion injury resulted in increased nitro-oxidative stress, DNA breakage, vascular cell adhesion protein 1, intercellular adhesion molecule-1, and caspase-3 scores, and a decreased endothelial nitric oxide synthase score in the free ITA groups. The in situ ITA graft showed no signs of injury. mRNA levels were significantly altered among the groups.

CONCLUSIONS

An early, severe endothelial dysfunction of the stored, free ITA as described, could be completely prevented by the use of an in situ ITA graft. Tiprotec might be a feasible option for storage of free arterial grafts during coronary artery bypass grafting.