Developement of pediatric size ventricular assist device for therapeutic use in profound heart failure after open heart surgery.

在儿童和成人中，有许多患者在心脏直视手术后发生严重的心力衰竭。由于IABP和静脉-动脉搭桥术并不有效和复杂，因此需要更有效和更安全的心脏辅助。为此，我们研制了儿童用气动隔膜式脑室辅助装置(VAD)。它的冲程容量为20毫升，由嵌段聚醚聚氨酯(TOYOBO TM系列)制成，包含两个#21比约克-希利阀。管道由聚氯乙烯制成，内表面涂有TM-3。进、出口导管内径分别为6 mm和8 mm。控制驱动装置与本中心成人使用的控制驱动装置相同。体外性能表明，该泵能产生足够的流量，并具有良好的跟随心动过速的能力。对幼年山羊(体重：9-17公斤)进行的慢性动物实验结果表明，儿童VAD在几个方面都具有优异的体内性能。这些特点包括易于植入、足够的循环支持能力、良好的抗血栓形成能力、高耐久性以及对幼年和未成熟动物的血液化学没有损害。他是一名3岁男孩，因室间隔缺损接受了手术。术后不能脱离体外循环，因此应用了VAD，全循环维持良好，术后3天因心脏恢复而脱离VAD，是治疗小儿术后严重心力衰竭的一种安全有效的方法。

In children as in adults, there are many patients who develop profound heart failure after open heart surgery. Since IABP and veno-arterial bypass are not effective and complicated, more effective and safer cardiac assistance is needed. So we have developed pediatric size air-driven and diaphragm type ventricular assist device(VAD) for children. Its stroke volume is 20 ml and it is made of segmented polyether polyurethane(TOYOBO TM-series) and contains two #21 Bjork-Shiley valves. The conduits are made of polyvinylchloride and their inner surface is coated with TM-3. The IDs of inlet and outlet conduet are 6 and 8 mm. The control drive unit is the same as that developed for adult use in our center.In vitro performance demonstrated that the pump could yield sufficient flow and had a good ability to follow tachycardia.The results of the chronic animal experiments using young goats(body weight: 9-17 kg) indicated that VAD for children had excellent in vivo performance in several aspects. These included ease of implantation, sufficient capability for circulrtory support, good antithrombogenicity, high durability and no harm on the blood chemistry of young and immature animals.And we had one clinical case. He was 3 year-old boy and operation was done for ventricular septal defect. After that he could not be weaned from extracorporeal circulation, so this VAD was applied.The entire circulation was well maintained and he was weaned from VAD after 3 days pumping because of his heart recovery.So we believe this VAD can be an effective and safe approach for treating the child with postoperative profound heart failure.