Twelve patients, nine with cardiac failure and three with respiratory failure, were treated with assisted cardiopulmonary bypass. One patient survived but the others died. Causes of death were cardiac failure in four patients, renal failure in four, cerebral damage in two, and bleeding in one. A new roller pump of 275mm in diameter was made for the assisted bypass and a closed bypass circuit was used. At present the assisted c-p bypass may be applied to the acute cardiac and pulmonary failure without any complications. In cases of severe cardiopulmonary failure the assisted bypass with high flow perfusion is required to improve the total tissue circulation. The blood damage mainly caused by pumping and the hemorrhagic tendency by heparin administration are the inevitable faults of the long time perfusion, and the minimization of these influences may lead to good results in cases of severe cardiopulmonary failure.
Sound spectroanalyses were carried out for diagnosis of malfunctioning prosthetic heart valves in 50 patients. Types of prostheses used in this series were Starr-Edwards silicone ball, metal ball and disc valves, Kay-Shiley valves, Smeloff-Cutter valves and Björk-Shiley valve. The system used in this study consisted of a moving coil microphone, a preamplifier, filter (160/24 db/octave) and a sound spectrograph (Rion Co. S. G. 07). Contour sound spectrograms were drawn and peak frequency, wave pattern and frequency-intensity curves were investigated as characteristics of implanted valvular function. Peak frequency of valvular opening and closing sounds were recorded between 1, 800 to 5, 000Hz and differed according to the types of prostheses. In mitral+aortic valve replacements, valvular sounds of each prosthesis were clearly separated and this findings were very useful to determine the malfunctioning prostheses. Decrease in peak frequency of valvular sounds or abnormal wave pattern in contour soundspectrograms was observed in 9 cases. Of the 9 cases, 4 cases underwent re-replacement and two cases died of congestive heart failure. Operative or autopsy findings of these 6 cases gave proof of the findings in sound spectroanalysis.
This study represents the experimental efforts directed to the development of vascular suture material which possesses the thromboresistant qualities. For this purpose, we prepared the nylon suture material immobilized urokinase by linking the urokinase to 7-0 nylon fiber. The procedure of immobilization was shown in Figure 1. Urokinase was linked to nylon through the grafted copolymer such as polyethyleneimine and gantrez (malefic anhydride/methylvinyl ether copolymer) by peptide linking. The fibrinolytic activity of this material was measured by the standard fibrin plate. These results were as follows: 1. This material was stable on storage at 4°C for over six months. 2. This material lost about 50% of initial fibrinolytic activity following a few repeated fibrinolysis test but retained 30-20% activity. 3. This material was influenced in fibrinolytic activity by added serum. 4. This material kept the favorable fibrinolytic activity after the procedure of disinfection. 5. This material showed the favorable antithrombotic action in the experiment of rabbit. The nylon suture material immobilized urokinase might be able to put to the practical utility in vascular surgery.
This study was designed to study the healing mechanism of vein prostheses. The morphological features of the inner capsules of prostheses implanted in dogs were examined by means of light and scanning electron microscopy. Expanded polytetrafluoroethylene vascular prostheses were implanted into the superior vena cava of dogs. The animals were sacrificed at 4 hours, 24 hours, 2 days, 3 days, 4 days, one week, two weeks, 6 weeks, 8 weeks and 10 weeks after implantation and the pellicle preparation then underwent gross examination, as well as light and scanning electron microscopic studies of the inner surface. At 24 hours after implantation, isolated neo-endothelial-like cells (spindle shaped) on fibrin mats were seen. Organization of thin thrombi was observed in localized regions adjacent to both suture lines and the fibrin mats were covered by neoendothelial cells at the proxymal anastomotic only one week after implantation. At two weeks after implantation, the organization of the inner capsule progressed more widely and there were neo-endothelial cells not only inwards from the ends but also in the central area. The spindle-like neo-endothelial cells were arranged along the line of blood flow. They then tended to become flatter and spread out. Numbers of isolated neo-endothelial cells were incorporated in the continuous sheets of new endothelium adjacent to the suture lines. By 10 weeks the entire inner surface of the graft was covered by neo-endothelial cells.
A new vertical type membrane oxygenator witht microporous film (Gelgard) was made at The Heart Institute of Japan, Tokyo, Japan. This microporous. membrane film made of non-wettable or wettablesubstances such as polypropylene is perforated with multiple small holes (mean size 0.1μ), which permits gas transfer very well. Main ideas were thought out in manufacturing the new vertical type membrane oxygenator as follows; 1. simple design. 2. small priming volume. 3. low resistance pressure. 4. sufficient gas transfer. The membrane oxygenator showed satisfactory results over these essential conditions.