The artificial esophagus, with which relatively short segment of the esophagus is replaced, was reviewed. When using free biological tissues such as aortic homograft, heterograft or autogenous free skin graft, the grafted tissue showed scarring or contractile changes for a long time and therefore the result was greatly depending on the dilation method. The result was generally unsteady, though some survived for longer than 5 years, as devising the stentt of lumen. When using a connective tissue tube generating around the replaced esophagus and a regenerated epithelium of the lumen as neo-esophagus, rather constant results longer than 3 years were reported by using the dilation me thod. Such technique may be prospero us to be applied practically, when divising the stent of lumen. When using the remaining tube prosthesis as an artificial esophagus, there were obtained results of observation for about 2 years, which may be further prolonged by devising the materials to be used and the method of replacement of the prosthesis. An artificial esophagus utilizing the organization of mesh gave a good result for up to about 1 year ; a geat advance of materials is required to get a good result for longer time according to this method.
We established a 17 days survival with an implaned total artificial heart in a calf. The blood contact surface was made of aldehyde treated bovine pericardium and the outer surface was reinforced with specially treated natural rubber. The artificial heart could pump more than 11l/min of water in vitro and 8l/min of blood in the experimental animal and was able to maintain hemodynamics within normal ranges for 17 days without difficulty. Though, to keep hematological parameters within normal ranges was relatively difficult, thromboembolism and disseminated coagulopathy characterized by bleeding were not large troubles at all. The main cause of death was breakage of the heart terminated in air embolism in the cerebral arteries.
It has been known that hemolysis would take place in the artificial circulation. The causes and mechanisms of hemolysis have been studied by many investigators. However, there were few papers which described the mechanism of hemolysis from the standpoint of energy metabolism of erythrocytes. In order to elucidate the energy metabolism of erythrocytes in the claves implanted with the biolized hearts, adenine nucleotides, such as ATP, ADP and AM P were analysed by the enzymatic method, together with routine hematological investigations. 4 claves were subjected to this study. Their survival was 41 to 408 hours. During the post-operative course ATP was decreasing, ADP increasing. This phenomenon strongely suggested the derrangement of feed back mechanism in the glycolytic pathways of calves erythrocytes. Crenocytes were found in greater percentage towards the end of experiments. Close relationship between ATP, ADP and % crenocytes was found. From these results it is considered that decrease of ATP contents would cause some morphological abnor mality of the erythrocytes during the artificial heart pumping. These crenocytes would be captured in the reticulo-endothelial system, and easily destroyed, which led to the extra-vascular homolysis. Appearance of crenocytes is one of the major factors of hemolysis. In addition to this other biological and mechanical factors concerning hemolysis should be taken into account.
This study has been undertaken to examine the possibility that permeability of dialysis membrane may be improved by adding CDP-cholin and antibiotics to dialysate. One liter of ultrafiltrate obtained from uremic patients is used as blood and recirculated at a flow rate of 200 ml/min and 1 liter of commercial dialysate is used as dialysate and recirculated at 500ml/min. Twenty-six grams of activated charcoal, 500mg of of baramycin, lg of streptomycin, 100mg of enramycin and 500mg of CDP-cholin are added to the dialysate and dialysances for urea, creatinine and others are obtained. Urea dialysance is 80ml/min without any additives. Urea dialysance is 83ml/min when activated charcoal is added and it increases to 95ml/min by adding ac ivated charcoal and baramycin. With activated charcoal and streptomycin, -dialysance increase to 100ml/min, and to 110ml/min when activated charcoal and enramycin are added. When CDP-cholin is added, it increases to 125 ml/min. Creatinine dialysance is 64ml/min whithout any additives, but is 68ml/min with activated charcoal, 73 ml/min with activated charcoal and baramycin, 77ml/ min with activated charcoal and streptomycin, 80ml/min with activated charcoal and enramycin, and 85ml/min with CDP-cholin. There is a possibility that actiavted charcoal CDP-cholin and some antibiotics might enhance transportation of substances through dialysis membrane and dialysance for various substances are increased.
The following conclusions were obtained from the study made to determine dose of heparin in periodically performed long term hemodialysis. Although the minimal requirement of heparin to prevent extracorporeal clotting during dialysis varies considerably from case to case, this remains within narrow range in individual case of repeated dialysis, if unaccompanied with complications. The initial heparin dose can be calculated from our formula given below. Initial dose of heparin (unit) =0.1×40/A ×circulatory blood volume×1.4 A: Clotting time of 1ml of blood from the patient, mixed in vitro with 0.1 unit of heparin. On the other hand, the maintenance dose of heparin per hour, which is in the range of 70-140% of initial dose, can be determined during dialysis. The dose should also be considered on the basis of the dialyser in use. Coil type dialiser requires the prolongation of clotting time to 3-4 times as that before the starting of dialysis (L. W. 40-50min.).
Antithrombogenicity of some graft copolymers was examined. For graft copolymerization, Teflon or Dacron vascular graft was irradiated in the monomer solution. The canine s;iperior or inf rarenal inferior vena cava was replaced with thQ irradiated graft. Internal surface 3f the graft was examined by autopsy or venography from one day to 26 months following replacement. Excellent thromboresistent property was recognized in Teflon-methyl-methacrylate and Dacron-2-hydroxyethy-lmethacrylate.
After replacement of heart valves, it is desirable to evaluate the movement of prosthetic valves. Echocardiography has been found to be useful for this purpose in the either mitral or aortic position. 59 consecutive cases of prosthetic valve replacement were examined with this method. In 22 cases of the mitral ball valve prosthesis, the movement of the ball and the cage, opening and closing velocities, poppet excursion and the ball diameter were measured. Average opening and closing velocities were 60mm/sec and 42mm/sec. Much difference in the velocities of ball movement was observed in individual patient. Moreover, it changed greatly from one heart beat to another especially in cases with arrhythmia. The Echocardiographic pattern of a normally functioning mitral ball valve prosthesis demonstrated great similarity to that of severe mitral stenosis. There were many kinds of Echocardiographic patterns in mitral Björk-Shiley disc valves. It seemed to be because of difficulty to keep the same angle between the direction of the ultra sonic beams and the movement of the tilting disc of the Björk-Shiley valve. Although the movement of the aortic valve prosthesis were detectable on Echocardiography, detailed analysis has not been completed in our study. An 8 year-old inl had developed signs and symptoms of malfunction of a Björk-Shiley disc valve (No. 25) and showed changes of Echocardiographic patterns of restricted disc movement in serial postoperative studies. At re-operation and valve replacement, we discovered thrombi encroaching on both sides of the valve orifice. The other patient was a 41 year-old male who had had both mitral and aortic value replacement a month ago. In spite of clinical findings of malfunction of the prosthesis, Echocardiography revealed pericardial effusion instead of a pattern of malfunction. It is effective and mandatory to perform serial postoperative studies on all patients with prosthetic valves.
The ultrastructure of pseudointima on the inner surface of the new vascular prostheses which are made up of polyester fabrics binding with Regitex-M, has been observed by the scanning electron microscope. In the initial stage, a network of fibrin appears on the luminal surface of the prosthesis and platelets scattered on the sheet of fibrin stretch out their pseudopods combining each other and firmly themselves with the underlying sheet of fibrin network. Then fusion of some flattened platelets is seen forming thin layer with rather smooth surface. Those deformities of platelets are considered as “vis-cousmetamorphosis”. Those thin smooth layers by viscous metamorphosis prevent further adhesion of platelets and other blood corpsucles but neo-endothelial cells grow over this smooth pavement. Irregulary shaped endothelial cells seen at advanced margin of the newly formed intima show many linear pseudopods binding each other. These linear pseudopods increase their width filling up the intercellular spaces. And the endothelial cell units to adjacent cells at their bordering rim showing some elevations or fingerlike projections just as be seen at normal intercellular junctions. These figures of pseudointima have been always seen, whether the prosthesis has high porosity or not. As endothelial cells are seen on the surface of a isolated intravascular non-woven cloth, the possibility of alteration to endothelial cells from some blood cells might be not denied.
1) Experience concerning checking the implanted 65 pacemaker generators with oscilloscope has been reviewed. The pulse shape is affected by not only a decrease in battery voltage and breakage of electrode but also other factors such as displacement of implanted generator, respiratory movement and direction of electrical stimulus. 2) The effect of those factors vary individually. Therefore, during implantation measurements of pulse shape with varying resistance and battery voltage using power supply and variable resister which was connected to the same model pacemaker as new one should be recorded as the control for later checking. 3) At the same time paring threshold could be measured. 4) The results of tests on 4 cases were reported to demonstrate typical findings such as battery exhaustion, electrode breakage, catheter displacement and unusual prolongation of pulse duration. 5) The data obtained before implantion can be useful in the detection of defects in the insuation of pacemaker electrode and the prediction of battery exhaustion. 6) The method discribed above for the control of implanted pacemaker generators justifies a longer use of them than is routine today. 7) So, it is our conclusion that a apparatus with variable resister and power supply to check the variation of pulse shape and the type of data should be supplied by manufacturer when a new model pacemaker is developed. 8) We think that more studies sh uld be made to investigate the factors varying pacemaker pulse shape to limit the number of sudden failures and to achieve maximum use of equipment.
It has been pointed out that myocardial infarction and severe combined valvular disease with intractable heart failure might be treated by instituting some kind of artificial circulatory system. Preparation or manipulation of the failing heart often results in ventricular fibrillation or standstill until bypass system has Established. Of all the artificial circulatory systems that have been evaluated for this purpose, the left heart bypass is to be preferred. This holds specially true, since Dennis et al. constructed a cannula with which this bypass could be accomplished without thoracotomy, but its clinical use has diminished for the risk of a ‘fausse-route’. Looking for the possibility of the suitable support system especially during and after open heart surgery for biventricular failure, we modified Dennis's cannula, making side openings which enable to drainage from both atria. The technique of placement of the transseptal cannula is rather easy and even in the reoperative case, smallest preparation of the right atrial wall allows easy insertion of this new cannula which enables to decompress whole heart directly and completely.
One hundred and five implantation of permanent cardiac pacemakers with transvenous endocardial electrodes or myocardial electrodes have been performed in 73 patients at the 1st Department of Surgery, University Hospital of Nagoya, from March, 1965, to January, 1974. Complications of implantable pacemaker have not been so minimal. In this series, two patients died with no relation to pacemaker implantation. One of them was lost with uncontrollable cardiac insufficiency after aortic and mitral valve replacement, and the other died of intracerebral hemorrhage. Myocardial electrodes were used in 42 cases and endocardial electrodes used in 31 cases. Incidence of dislodgement of catheter electrode was approximately 20% and wire fractures of myocardial electrode occurred 8 times in 6 patients, 20% in our series. As myocardial electrode is improved at the present time, this kind of trouble has not been experienced since last year. A characteristic finding on ECG was seen in all cases of wire fracture. Concerning the operative procedure, it is easier to implant the endocardial electrode, but many unsolved problems remain for its fixation in the ventricular cavity. As the greater part of dislodgement of transvenous endocardial electrode is not only due to the morphological factor of the heart b t also due to tention, flexibility and hardness of inserted electrode in the ventricular cavity, this complication is likely to be unavoidable. Fixation of myocardial electrode, however, is satisfactory and with this respect, in our clinic, myocardial electrode implantation is treatment of choice rather than endocardial electrode implantation. In the future, cases of implantation of pacemaker will be increased day by day and many kinds of pacemaker trouble will be supposed to occur far from medical center. Therefore, author insists that aftercare system of pacemaker is necessary to be organized throughout our country.