Coronary occlusion using bi-directionally stretched elastic sutures during off-pump coronary artery bypass grafting

Off-pump coronary artery bypass grafting may be partly invasive, particularly to the coronary endothelium that is snared. Efficacy of a simple technique to occlude a coronary artery with elastic sutures bi-directionally stretched just beneath the artery was evaluated.

Test subjects were eighteen adult mongrel dogs weighing 20-30 kg. After systemic heparinization (150 U/kg), the mid-left anterior descending artery (mid-LAD) was exposed with a stabilizer applied and snared using non-elastic sutures (n = 6) or elastic sutures (n = 6), or occluded with elastic sutures bi-directionally stretched (n = 6). The left internal thoracic artery (LITA) was anastomosed to the mid-LAD with humidified gas insufflation. After completion of the anastomosis, the mid-LAD was observed endoscopically through the LITA. The coronary endothelium was also observed by a scanning electron microscope (SEM) after perfusion fixation.

Bleeding at the anastomotic site with the coronary artery occluded by bi-directionally stretched elastic sutures was observed. However, all anastomoses were done successfully with the aid of humidified gas insufflation. Coronary endoscope showed that the lumens snared with non-elastic sutures were collapsed with folds and often with clots. Coronary arteries snared with elastic sutures appeared similar to the arteries snared with non-elastic sutures endoscopically, but with less clots. In the case of coronary occlusion with bi-directionally stretched elastic sutures, the lumens were occluded in a flattened linear fashion without clots. SEM showed endothelial injuries with blood cells deposited when non-elastic sutures were used. When elastic sutures were used for snaring, endothelial injuries were ameliorated with less blood cells deposited, which were further decreased when elastic sutures were bi-directionally stretched.

The coronary artery can be effectively occluded by bi-directionally stretched elastic sutures with minimal endothelial damage.