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At present, only the autogenous saphenous vein is acceptable in aorta-coronary bypass grafting. We developed a small-caliber vascular graft and evaluated the potential application for aorta-coronary bypass grafting. Canine carotid arteries were cross-linked with polyepoxy compounds, such as polyglycerol polyglycidyl ether, which is a new cross-linking reagent, and then heparinized by our own method. The polyepoxy compound-cross-linked graft can keep the natural vessel compliance and is stronger than the glutaraldehyde-cross-linked graft; thus, it provides excellent suturability and compliance match. Heparin was gradually released from the graft wall, and thrombus formation was completely prevented during the period before development of the endothelial lining. As a pilot study, the grafts, 2 to 3 mm in internal diameter and 5 to 7 cm in length, were evaluated as bilateral carotid replacements in five dogs. All grafts were patent at intervals of 14 to 177 days. Histologic examinations showed excellent antithrombogenic and healing characteristics, although the endothelialization was delayed by heparin, which inhibits cell adhesion and fibrin deposition. The 3 mm internal diameter graft was evaluated as an aorta-coronary bypass grafting model in eight dogs. Flow within grafts to the right coronary artery ranged from 25 to 35 ml/min, and flow in the circumflex or left anterior descending grafts ranged from 75 to 100 ml/min. Cineangiography was performed to confirm graft patency. Three dogs died of viral infection and one was killed. At necropsy, the grafts remained patent without thrombi along the graft length. Four dogs were allowed to survive for long-term evaluation. All grafts were patent at time intervals to 21 to 113 days with 100% patency. These results led us to conclude that our newly developed small-caliber vascular graft shows great promise in application for aorta-coronary bypass grafting.

This study was undertaken to evaluate the optimal myocardial temperature during a 4-hour ischemia induced by blood potassium cardioplegia (PC). Heart-lung preparations with work load circuit were used as experimental model. 24 mongrel dogs were divided into four groups and two myocardial temperatures (moderate hypothermia, deep hypothermia) and two perfusates (PC with blood, PC without blood) were tested. Parameters used to evaluate the myocardial protection include the coronary sinus blood pH of the initial reperfusion and left ventricular stroke work after resuscitation. In blood PC at moderate hypothermia, deleterious acid metabolites were minimally produced as evidenced by the coronary sinus blood pH (7.221 +/- 0.122) at initial reperfusion, and cardiac function was best recovered in this group. Blood PC at moderate hypothermia allows the heart to tolerate 4 h ischemia without an excessively elevated coronary perfusion pressure during cardioplegic infusion.

Arterial and venous catheterization is a very useful procedure in the diagnosis of heart diseases. However, some complications with thrombogenesis have been reported. Two kinds of Mikaelson-type non-heparin-coated angiographic catheters (with 6.5 Fr. and 80 cm length) were used for the experiments. One was of polyurethane (PUC) and the other of polyethelene (PEC). Eight experimental dogs were used for each group. The catheter was inserted into the ascending aorta through the femoral artery. No antithrombogenic drugs were given to the animal. One hour later, sodium heparin (100 U/kg) was administered intravenously. The animal was sacrificed by acute exanguination. The aorta was opened longitudinally. The position of the thrombi on the aortic wall was macroscopically observed and the weight of the thrombi attached to the catheters were measured. A piece of the aorta at each level was excised for light and scanning electron microscopic observations. Mural thrombi of various lengths still remained on the aortic wall of every dog after the removal of the catheters. Microscopic observation revealed that the mural thrombus was formed on the aortic wall, where the endothelial cells had peeled off and the internal elastic membrane was partially destroyed. SEM observation also showed that fibrin network on the aortic wall where the endotherial cells were peeled off. Microscopic observation of aortic wall also revealed intimal tears, inner elastic membrane injury and bleeding in the elastic membrane. This damage could worsen leading to dissection of the aorta, thrombosis of the abdominal organs. The injury is considered due to mechanical irriation by the catheter.(ABSTRACT TRUNCATED AT 250 WORDS)