McCarthy P M, Fukamachi K, Fukumura F, Muramoto K, Golding L A, Harasaki H
Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic Foundation, Ohio 44195.
J Thorac Cardiovasc Surg. 1994 Sep;108(3):420-8.
In vitro function of the Cleveland Clinic-Nimbus electrohydraulic total artificial heart met National Heart, Lung, and Blood Institute hemodynamic guidelines for such devices. In a series of in vivo experiments, we implanted the total artificial heart in eight calves (mean weight 87 kg), one for a short-term experiment and seven for long-term experiments. The mean blood flow during support was 7.7 +/- 1.6 L/min with left atrial pressure 13 +/- 6 mm Hg, right atrial pressure 13 +/- 4 mm Hg, and aortic pressure 97 +/- 9 mm hg. Maximum pump flow (9.6 L/min) occurred after 4 days of support as a result of the high resting cardiac output of the animals. A 10% to 15% right pump stroke-volume limit effectively balanced atrial pressures, and afterload insensitivity was confirmed by the in vivo studies. Calves tolerated treadmill exercise studies well, with an average duration of 22 minutes and an average top speed of 2.1 mph. The experiments were terminated after 1 day to 120 days of support (mean 32 days). Most experiments were terminated as a result of correctable mechanical problems. In a separate study of six adult human patients undergoing orthotopic cardiac transplantation, five showed an excellent fit for the Cleveland Clinic-Nimbus total artificial heart. Further studies using chest roentgenograms, chest measurements, and transesophageal echocardiography should help predict fit of the total artificial heart in potential candidates. Initial candidates for a "vented-electric" version of the Cleveland Clinic-Nimbus total artificial heart are patients for whom univentricular (left ventricular assist device) support is not appropriate, but who require mechanical support as a bridge to cardiac transplantation.
克利夫兰诊所-宁布斯电动液压全人工心脏的体外功能符合美国国立心肺血液研究所针对此类设备的血流动力学指南。在一系列体内实验中，我们将全人工心脏植入八头小牛（平均体重87千克）体内，一头用于短期实验，七头用于长期实验。支持期间的平均血流量为7.7±1.6升/分钟，左心房压力为13±6毫米汞柱，右心房压力为13±4毫米汞柱，主动脉压力为97±9毫米汞柱。由于动物静息心输出量较高，支持4天后出现最大泵流量（9.6升/分钟）。右泵冲程容积限制在10%至15%时可有效平衡心房压力，体内研究证实了后负荷不敏感性。小牛对跑步机运动研究耐受良好，平均持续时间为22分钟，平均最高速度为2.1英里/小时。支持1天至120天后（平均32天）实验终止。大多数实验因可纠正的机械问题而终止。在另一项对六名接受原位心脏移植的成年患者的研究中，五名患者显示克利夫兰诊所-宁布斯全人工心脏非常合适。使用胸部X光片、胸部测量和经食管超声心动图的进一步研究应有助于预测潜在候选者中全人工心脏的适配情况。克利夫兰诊所-宁布斯全人工心脏“通气式电动”版本的初始候选者是那些不适合单心室（左心室辅助装置）支持，但需要机械支持作为心脏移植桥梁的患者。
