Aortocoronary Bypass Grafting with Hydrophilic Small Caliber Vascular Grafts

Previous work showed that the authors' vascular graft had satisfactory antithrombogenicity because of high hydrophilicity. The authors developed a small-caliber xenograft using new technology and evaluated the potential application for aortocoronary bypass grafting. Fresh sheep carotid artery with an internal diameter of 3 mm was obtained, and cross-linked with hydrophilic polyepoxy compounds. A 6 cm segment of the graft was then used between the aorta and the left circumflex coronary artery without cardiopulmonary bypass in 17 dogs. Sodium heparin was given during the surgery, but no anticoagulant was used thereafter. After the surgery, the dogs were randomly assigned to two groups according to the observation period. In 11 animals (Group 1), the observation period was up to 24 hr, at which time the grafts were evaluated; the patency rate was 72.7%. The patent grafts were clean and without thrombi. At the distal anastomotic lines of the occluded grafts, a thrombus was observed and a technical error was highly suspected. In six dogs (Group 2), angiography was performed to confirm graft patency between 2 and 3 weeks. The patency rate was 50% during the mean observation period of 17.5 days. One graft was evaluated at postoperative day 23. It was patent and soft, and the inner surface was shiny and smooth. Microscopic observation showed nice healing characteristics. These results indicate that it is possible for this new graft to be used for aortocoronary bypass grafting.