Department of Cardiovascular Surgery, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77225-0345, USA.
J Heart Lung Transplant. 2010 Jun;29(6):687-91. doi: 10.1016/j.healun.2009.12.017. Epub 2010 Feb 4.
In this study, we describe the potential advantages of a continuous-flow total artificial heart (CFTAH) comprising two small, non-pulsatile pumps with optimized responsiveness to the pressure gradient.
We modified a MicroMed DeBakey axial-flow pump by increasing its inducer-impeller inlet angle, thereby increasing its pressure responsivity. We obtained the in vitro pressure gradient response and compared it with those of the clinically used, unmodified MicroMed DeBakey pump, Jarvik 2000 FlowMaker and HeartMate II.
The modified pump showed an increased response to changes in the pressure gradient at pump flow rates of between 2 and 4 liters/min. The maximum pressure responsivity of the modified pump was 2.5 liters/min/mm Hg; the corresponding maximum responsivities of the Jarvik 2000, HeartMate II and MicroMed DeBakey ventricular assist devices (VADs) were 0.12, 0.09 and 0.38 liters/min/mm Hg, respectively.
Because of the inherent properties of non-pulsatile pumps, the CFTAH may potentially respond to changes in inflow and outflow pressures while maintaining physiologic flow rates sufficient for normal daily activity. In addition, the hemodynamic interplay between the two optimized pumps should allow a physiologic response to normal flow imbalances between the pulmonary and systemic circulations. Improved responsiveness to inflow pressure may further simplify and improve the CFTAH and affect its potential clinical use as a meaningful therapy for terminal heart failure.
在这项研究中，我们描述了一种由两个小型非搏动泵组成的连续流全人工心脏（CFTAH）的潜在优势，这两个泵具有优化的压力梯度响应能力。
我们通过增加微医德贝基轴流泵的诱导叶轮入口角度来修改该泵，从而提高其压力响应性。我们获得了体外压力梯度响应，并将其与临床使用的未修改的微医德贝基泵、Jarvik 2000 FlowMaker 和 HeartMate II 进行了比较。
在 2 至 4 升/分钟的泵流量下，改良后的泵对压力梯度的变化表现出更高的响应。改良后的泵的最大压力响应性为 2.5 升/分钟/毫米汞柱；相应的 Jarvik 2000、HeartMate II 和微医德贝基心室辅助装置（VAD）的最大响应性分别为 0.12、0.09 和 0.38 升/分钟/毫米汞柱。
由于非搏动泵的固有特性，CFTAH 可能能够在维持足够满足正常日常活动的生理流量的同时，对流入和流出压力的变化做出反应。此外，两个优化泵之间的血液动力学相互作用应该允许对肺循环和体循环之间正常流量失衡做出生理反应。对流入压力的响应性提高可能进一步简化和改进 CFTAH，并影响其作为终末期心力衰竭的有意义治疗方法的潜在临床应用。
