Wurzel D, Kolff J, Missfeldt W, Wildevuur W, Hansen G, Brownstein L, Riebman J, De Paulis R, Kolff W J
Cardiac Systems, Inc., Conshohocken, PA 19428.
Artif Organs. 1988 Oct;12(5):410-22. doi: 10.1111/j.1525-1594.1988.tb02796.x.
A new pneumatic artificial heart system has been developed. The design criteria have been to produce an integrated series of blood pumps and drive systems that would reduce blood trauma and reactivity, while incorporating industrial, mass-production techniques. The system attempts to reproduce the natural heart's pressure and flow waveforms and allows the prosthetic valves to be installed in a manner consistent with their design. The system's ventricles are constructed entirely of polyurethane by a combination of vacuum-forming and solution-casting techniques. The atrial cuffs and arterial grafts are permanently attached to the pumps and do not incorporate a quick connect system. The prosthetic valves are sewn into the inflow and outflow tracts using their clinical sewing rings. Besides eliminating the crevices normally found in quick connect systems, this method mounts the valves in an extremely compliant housing to increase shock absorption. The drive system produces a systolic air flow with a variable pressure rise (dP/dt) to reduce mitral valve closing velocity. This system has been implanted into 25 calves to date, of which 17 were chronic experiments. In 14 animals, St. Jude bileaflet valves were used and these animals had a mean survival of 39 days. Six of these animals survived over 30 days, with the longest being 129 days. All of the animals showed the characteristic postoperative drop in red blood cell count and hematocrit that returned to near preoperative values in about 3 weeks. The plasma free hemoglobin values generally remained below 5 mg/dl. The necropsies performed on several of the earlier animals revealed renal infarcts. However, in two of the later experiments, no kidney damage was found. The blood contacting surfaces of the atrial cuffs from the animals surviving over 100 days were covered with a fibroproliferative pseudoneointimal growth that extended from the sewing rings to the natural atrial tissue. Grossly, this appears to be the same type of tissue response seen when only a valve is implanted in a natural calf heart.
一种新型的气动人工心脏系统已被研发出来。其设计标准是制造一系列集成的血泵和驱动系统，既能减少血液损伤和反应性，又能融入工业大规模生产技术。该系统试图重现自然心脏的压力和血流波形，并允许以与其设计一致的方式安装人工瓣膜。该系统的心室完全由聚氨酯通过真空成型和溶液浇铸技术组合制成。心房袖带和动脉移植物永久性地连接到泵上，不采用快速连接系统。人工瓣膜使用其临床缝合环缝入流入道和流出道。除了消除快速连接系统中常见的缝隙外，这种方法还将瓣膜安装在一个极其柔顺的外壳中以增加减震效果。驱动系统产生具有可变压力上升（dP/dt）的收缩期气流，以降低二尖瓣关闭速度。到目前为止，该系统已植入25头小牛体内，其中17例为慢性实验。在14只动物中使用了圣犹达双叶瓣膜，这些动物的平均存活时间为39天。其中6只动物存活超过30天，最长的为129天。所有动物术后均出现红细胞计数和血细胞比容特征性下降，约3周后恢复至术前值附近。血浆游离血红蛋白值一般保持在5mg/dl以下。对几只早期动物进行的尸检显示有肾梗死。然而，在后来的两个实验中，未发现肾脏损伤。存活超过100天的动物心房袖带的血液接触表面覆盖着从缝合环延伸至天然心房组织的纤维增生性假内膜生长。总体而言，这似乎与仅在天然小牛心脏中植入瓣膜时观察到的组织反应类型相同。
