Left heart bypass was performed with Bio Medicus Co.-made Bio-pump, a representative centrifugal pump. A vinyl chloride tube for the usual cardio-pulmonary bypass not treated with antithrombogenic material. was used in the bypass circuit. In the experiment, the mongreal adult dogs were divided into the systemic heparinized group and non-heparinized group and the bypass was performed for 6 hours. As a result, coagulation and fibrinolysis were more activated in the non-heparinized group than the other group. So, when this method is used clinically, a small quantity of heparin should be administered. Clinically, this approach was used as an adjunct in operation for 7 cases of thoracic aortic aneurysm. During left heart bypass, a small quantity of heparin (0.5-1.0mg/kg) was administered. A rise in FPA and FDP considered attributable to autotransfusion during the operation was noted. Distal perfusion could be performed fully and the amount of bleeding during and after operation was small, but 1 case each of acute renal failure and paraplegia as postoperative complication was encountered. Neither was considered due to left heart bypass; and, changes in respiratory system and hepato-renal function were considered within the tolerable range. These results have led us to believe that left heart bypass using Bio-pump is safe and useful as an adjunct in operation for thoracic aortic aneurysm and should be used positively in the future.

We have examined the role of readmission of oxygen in the initiation of reperfusion-induced arrhythmias by separating readmission flow from readmission of oxygen on a temporal basis. Isolated rat hearts (n=12/group) were subjected to 10 minutes of global ischemia and reperfusion. In controls reperfused with aerobic perfusion medium, 100% of hearts developed ventricular tachycardia 1.48±0.78 seconds after reperfusion, and ventricular fibrillation occurred 13.47±2.91 seconds after reperfusion. Also in hearts reperfused with anoxic perfusion medium, 100% of hearts developed ventricular tachycardia 1.98±0.96 seconds after reperfusion, and ventricular fibrillation occurred 27.01±18.52 seconds after reperfusion. But the duration of the time from reperfusion to the onset of ventricular fibrillation were statistically differrent in these two groups (p<0.05). In conclusion anoxic reperfusion delayed ventricular fibrillation but prevent neither ventricular fibrillation nor ventricular tachycardia. This implies that oxygen-derived free radicals may play an important role in the initiation of reperfusion-induced arrhythmias, but are unneccessary for arrhythmogenesis.

This study was designed to evaluate the myocardial protection with observation of the monophasic action potential (MAP) which was recorded by suction electrode. Using the isolated working rabbit hearts, amplitude, duration of MAP at 50% repolarization level (MAPD₅₀), aortic flow and heart rate were measured after reperfusion. The comparative study obtained for all five groups under the following various conditions of the aortic cross clamping are stated as follows. Myocardial temperature were maintained at 20°C during aortic cross clamping. Group I was treated with St. Thomas' Hospital cardioplegic solution. The cardioplegic solution was infused every 20min during ischemia and kept at 20°C. The hearts of group I was divided into four sub-groups, all of which were infused with different concentration of diltiazem (D) in cardioplegia: group Ia D=0μg/ml (n=10), group Ib D=1μg/ml (n=5), group Ic D=5μg/ml (n=5). group Id D=10μg/ml (n=5), and in group II cardioplegic solution was not used. The amplitude of MAP following 30min working mode of reperfusion in group I showed a significantly higher recovery compared to those in group II. The MAPD₅₀ of MAP following 30min working mode of reperfusion in group I showed a significantly lower recovery compared to those in group II, and 10min Langendorff mode in group I a showed a significantly higher recovery compared to those in group Ib, group Ic and group Id. 20min working mode in group Ia and group Ib showed a significantly higher recovery compared to those in group Ic and group Id. The heart rate following 30min working mode of reperfusion in group Ia and group Ib showed a significantly higher recovery compared to those in group Ic and group Id. The aortic flow following 30min working mode of reperfusion in group Ia and group Ib showed a significantly higher recovery compared to those in group Ic, group Id and group II. We would like to conclude that the permeability of large amount of calcium across myocardial cell membrane seems to be depressed by diltiazem added to cardioplegia. But when the concentrations of diltiazem in cardioplegia was over 5μg/ml, it showed negative inotropic action and negative chronotropic action.

We have recently experienced a case of impending ruptured aneurysm of the common iliac artery associated with a gelatinous substance in the retroperitoneal space. A 69 year-old male had been diagnosed as a left common iliac aneurysm at another hospital by CTscan during the examination of lower abdominal pain. At the midnight of the day he admitted, the severity of pain gradually intensified. But there was no sign of anemia nor hypotension. Next morning CTscan showed low density left retroperitoneal mass. The patient underwent emergency laparotomy. The further inspection revealed about 600cm³ of gelatinous substance in left retroperitoneal space without the sign of aneurysmal rupture. A bifurcated graft replacement was performed. The low density mass was not recognized by CTscan done 42 days postoperatively. Electrolyte study of the gelatinous substance indicated its serous leakage through the impending ruptured aneurysm. Our present report constitutes a completely distinct variety of common iliac aneurysm, associated with a gelatinous substance in retroperitoneal space without a major rent of the aneurysmal wall.

Twenty six adult patients who underwent prosthetic heart valve replacement and treated anti-thrombogenic therapy, were divided into 2 groups. One was administered Warfarin alone, another was administered Warfarin plus Aspirin (162mg/day) as antiplatelet therapy. Trapidil (300mg/day) was administered to all of the patients. Platelet aggregation, plasma level of TXB₂ (stable metabolite of thromboxane A₂), and 6-keto-PGF₁ (stable metabolite of PGI₂) were measured before and 1, 3, 6 months after Trapidil therapy. Platelet aggregability suppressed in both 2 groups. Plasma TXB₂ level, and TXB₂/6-keto-PGF₁ ratio showed a tendensy to decrease (p<0.05) 6 months after administration. In the Aspirin plus Trapidil group, platelet aggregability, serum TXB₂ level, and TXB₂/6-keto-PGF₁ ratio are significantly lower than that in the Trapidil only. These results suggest that Trapidil is clinically useful for antiplatelet agent, but the combined Aspirin plus Trapidil therapy is more efficacious than the Aspirin or Trapidil single therapy.