Cryopreserved Veins in Myocardial Revascularization: Possible Mechanism for Their Increased Failure

Background. Cryopreserved veins are used as conduits for myocardial revascularization. However, a high failure rate associated with their use has been reported anecdotally. Methods. To find an explanation for the poor performance of cryopreserved vein grafts, we conducted a retrospective 5-year study on all patients at a single institution in whom cryopreserved vein grafts were used. We further performed in vitro studies measuring cell adhesion, nitric oxide production, and contractile capacity of saphenous vein, internal thoracic artery, and cryopreserved veins. Results. Forty-one patients were identified in whom one or more cryopreserved veins were used as a last resort. Sixteen had events (death or recatheterization). Seven deaths occurred (17%). Event-free survival was 50% at 12 months. Activated granulocyte/monocyte endothelial adherence could be lowered in internal thoracic arteries and saphenous veins with morphine incubation (50% and 57%, respectively), but not in cryopreserved veins. Simultaneous increases in nitric oxide release were also found in internal thoracic arteries and saphenous veins, but not cryopreserved veins. In addition, cryopreserved veins showed a diminished contractile capacity under experimental conditions. Conclusions. In this highly select group of patients, cryopreserved veins had a high early failure rate, which may be partially due to the inability of the endothelium to participate in immunovascular processes.