The surface-coated vascular stent of shape memory alloy was made for use of occlusion of pseudo-lumen of the dissecting aneurysm of the aorta, as the usage of shape memory alloy in angioplasty, and the metal flexible delivery catheter was also made for the introduction of the stent. In the present study, antithrombogenicity of the vascular stent was much improved by surface-coating with EPTFE and segmented polyurethane. The long-term usage of the stent was confirmed by radiological, macroscopic, and electron microscopic examinations. Moreover, the metal flexible delivery catheter was demonstrated to be of much benefit for the introduction of the surface-coated vascular stent of shape memory alloy.

In order to reduce the blood transfusion volume in open heart surgery, the new blood autotransfusion technique using cardiotomy reservoir unit BCR 3538, which was configured to serve also as a receptacle for postoperative mediastrinal drainage, was introduced. To investigate the utility and the problem in this system, every clotting factor, platelets' function and the extent of the hemolysis were measured serially both in patients' arterial blood and the shed mediastinal blood. The bank blood transfusion was significantly reduced to 250ml±330ml by this system compared to the 1080ml±820ml in the cases of usual system (p<0.01). Every clotting factor recovered well in patients' arterial blood after cardiopulmonary bypass (CPB). In the reservoir blood, the clotting factor IX, XI, XII were extremely suppressed at 1h CPB, and 3h after the CPB, every clotting factor except fibrinogen (42±28mg/dl) showed the quite higher activity, such as factor VIII 400%, IX 365%, XI 72%, XII 267%. Namely, the anticoagulability of the reservoir blood was maintained due to the effect of the residual heparin at 1h after the CPB, and due to the contact defibrinogation of the shed mediastinal blood at 3h after CPB. The free hemoglobin level was extremely high on the reservoir blood at 3h after CPB. In 6 cases, the autologous blood retransfusion was abandoned by clott formation in the unit because of the contamination of the intraoperatively used fibrin glue. From this study, the autologous blood transfusion using cardiotomy reservoir BCR 3538 was useful not only for saving the transfusion of the bank blood but also the hemostasis after CPB. But to reduce the hemolysis in this system, and to establish the safety against the other clotting material such as fibrin glue were the problems which should be resolved in future. I appreciate the kind support of Alexander von Humboldt Foundation for this study.

An emergency percutaneous cardiopulmonary support system (PCPS) was employed 11 arrest victims (5 males, 6 females; mean age 59.3 years) refractory to conventional resuscitation measures. Cardiac operation was subsequently performed in two patients and coronary angioplasty in two. The 7 other patients continued on cardiopulmonary support by PCPS after successful resuscitation. Duration of support was 10.5±9.1 (mean±S. D.) hours, the flow rate was 2.5±0.7l/min, and PCPS was applied 5-70min (mean, 24.9min) following the onset of cardiac arrest. The entire intraluminal surface of PCPS device had been heparin coated, activated coagulation time was maintained about 150 seconds, with or without minimal systemically administered heparin. Seven of 11 patients (63.6%) were successfully weaned from the PCPS. The early survival (<30 days) was 6 patients (54.5%), and late survival was 4 patients (36.4%). We conclude that PCPS can improve survival in patient unresponsive to conventional resuscitation when instituted soon after cardiac arrest.

Between December of 1989 and May of 1993, 7 of 338 patients (2.1%) who underwent median sternotomy for cardiac operations developed mediastinitis. All of these infections caused by Staphylococcus species. Six of seven patients with mediastinitis were successfully treated with debridement, irrigation and omental transposition into the mediastinum. Between December of 1989 and May of 1992, sterile bone wax was used as a hemostatic agent in 233 of these patients. Between June of 1992 and May of 1993 an argon beam coagulator was used in place of bone wax in 105 patients. The incidence of mediastinitis significantly differed in relation to whether patients received bone wax or not (7 of 233 patients who did (3.0%) versus none in 105 patients who did not (0%) p<0.01). We conclude from this study that bone wax may be a promoting agent in postoperative mediastinitis, so the routine use of bone wax should be reconsidered.

Fifteen consecutive patients with true or dissecting aneurysms of the thoracic descending aorta, and thoraco-abdominal aorta were operated upon under left thoracotomy with the support of partial cardiopulmonary bypass, equipment composed of a membrane oxygenator, centrifugal pump, and percutaneous thin wall cannulae which were all coated with covalently bonded heparin. The polyvinyl tube was coated with Biomate. The administration of systemic heparin was determined by an ACT of around 200 seconds. One perioperative death in a case treated by emergency operation for a ruptured descending aortic aneurysm occurred due to acute myocardial infarction. Other patients tolerated their operation well and are alive. No thromboembolic accident, bleeding tendency, nor organ failure were observed postoperatively in any other patients. In conclusion, the cardiopulmonary bypass using an antithrombotic circuit is safe and recommendable for thoracic descending or thoraco-abdominal aneurysm operations.