Self-Sensing Physiologic Control of a Rotary Mag Lev LVAD

旋转磁悬浮 LVAD 的自感知生理控制

• 批准号: 7923133
• 负责人: James Farley Walton
• 金额: $ 37.38万
• 依托单位: MOHAWK INNOVATIVE TECHNOLOGY, INC.
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7923133
• 关键词: Acute; Adult; Algorithms; American; American Heart Association; Analog Computers; Animal Testing; Animals; Architecture; Assisted Circulation; Back; Biological Models; Cardiac Output; Cardiovascular Diseases; Cardiovascular system; Cause of Death; Chronic; Communities; Computer Simulation; Congestive Heart Failure; Coronary Arteriosclerosis; Data; Data Sources; Destinations; Development; Device Designs; Devices; Evaluation; Event; Funding; Generations; Goals; Grant; Heart; Heart Diseases; Heart Transplantation; Heart failure; Heart-Assist Devices; Human; Hypertension; In Vitro; Investigation; Journals; Left; Left ventricular structure; Magnetism; Measures; Mechanics; Medical center; Modeling; Modification; Morbidity - disease rate; Motion; Motor; National Heart, Lung, and Blood Institute; Output; Patients; Performance; Phase; Physiological; Publishing; Pump; Rotation; Running; Scheme; Signal Transduction; Simulate; Small Business Innovation Research Grant; Speed; Suction; System; Testing; United States; United States National Institutes of Health; Update; Variant; analog; design; digital; hemodynamics; improved; in vitro testing; in vivo; innovation; mathematical model; meetings; mortality; novel; novel strategies; pressure; programs; prototype; public health relevance; response; sensor; simulation; simulation software; success; symposium; ventricular assist device

DESCRIPTION (provided by applicant): Heart failure is the number one cause of death in the United States and presents an increasing public burden of morbidity and mortality even as the mortality from coronary artery disease and hypertension is decreasing. While an estimated 40,000 congestive heart failure patients are candidates for heart transplantation, only 2,200 donor hearts are made available each year highlighting the need for mechanical circulatory support. In its efforts to develop new treatments of cardiovascular diseases, the NIH NHLBI has funded development of pulsatile and nonpulsatile mechanical circulatory assist devices (MCADs). While, current use of MCADs is increasing, many more patients would benefit if fully implantable and wearable devices with physiologic control systems were available. MiTi's ultimate goal is an implantable rotary Left Ventricular Assist Device (LVAD) with physiologic controller for destination therapy in adult heart failure patients. Key and novel features of the proposed self sensing physiologic controller are its ability to use motor and magnetic bearing signals to adjust LVAD output in response to cardiac output changes through the use of differential pressure and flow estimators all while avoiding suction. The specific goals of this project are to design, implement and demonstrate physiologic control of the MiTiHeart(R) LVAD output through computer simulations, in vitro and in vivo tests. Specifically, MiTi(R)'s Mock Circulator System (MCS) will be modified to more accurately model left ventricle hemodynamics, the physiologic control algorithms having differential pressure, flow and suction avoidance objective functions will be implemented in the MiTiHeart(R) LVAD controller and evaluated in the MCS. Electric analog computer simulations of the MCS and LVAD will be updated and tuned to match the measured data so that evaluations of additional control algorithms and system physical changes can be simulated including replacing the MCS model with a human cardiovascular system model. Finally, in vivo acute animal studies will be completed at Penn State Hershey Medical Center to demonstrate the ability of the physiologic controller to adjust LVAD output without entering suction. The following Specific Aims are planned: (1) Design and implement modifications to the MiTi(R) MCS to more accurately model left ventricle hemodynamics by incorporating improved simulation of left ventricle (LV) ejection flow and pressure. (2) Modify the mathematical model of the MCS developed in Phase I to accept an enhanced LVAD performance model including the physiologic control algorithm. Tune the integrated mathematical model to reflect the measured performance in the MCS. Use the optimized model to assess the ability of the LVAD and controller to respond to simulated changes first in the MCS model and then with a human cardiovascular system (CVS) model. Simulations with both MCS and CVS models will then be performed using the enhanced models to assess performance of the LVAD and physiologic control system under a wide variety of conditions to verify the ability of the controller to vary output with changing physiologic demand while also avoiding suction. (3) Evaluate the physiologic control system performance, suction avoidance and pump differential pressure and flow estimations via in vitro testing in the updated MCS. The physiologic control algorithms and architecture developed under Phase I will be implemented in a dSpace digital control hardware system. The control system will then be used with the MiTiHeart LVAD to characterize and verify the proposed control system in the updated MCS. MCS testing under different simulated heart conditions that encourage suction events will be conducted. (4) Conduct three in vivo acute animal studies to validate performance of the physiologic controller including estimating differential pressure and flow as well as detecting and avoiding suction where the animal heart CO will be pharmacologically modified. PUBLIC HEALTH RELEVANCE: According to the American Heart Association [1], approximately one million Americans die each year from heart disease and almost 4.7 million Americans have congestive heart failure (CHF), a chronic condition in which at least one chamber of the heart is not pumping well enough to meet the body's need. With more than half a million new cases of CHF and only 2,200 donor hearts available for almost 40,000 heart transplantation candidates every year, there is a pressing need for new treatment options such as mechanical circulatory assist devices or heart assist pumps [2]. The success of early developments has resulted in the use of circulatory assistance for short durations [2, 3, 4], however new developments are needed to make long duration use of these heart assist devices possible.

描述（由申请人提供）：心力衰竭是美国的头号死亡原因，尽管冠状动脉疾病和高血压的死亡率正在下降，但心力衰竭的发病率和死亡率仍在增加，这是公众负担。虽然估计有40,000名充血性心力衰竭患者是心脏移植的候选者，但每年只有2,200名供体心脏可供使用，这突出了对机械循环支持的需求。为了开发心血管疾病的新疗法，NIH NHLBI资助了脉动式和非脉动式机械循环辅助装置（mcad）的开发。虽然目前mcad的使用正在增加，但如果具有生理控制系统的完全植入式和可穿戴设备可用，更多的患者将受益。MiTi的最终目标是为成人心力衰竭患者提供具有生理控制器的可植入式旋转左心室辅助装置（LVAD）。所提出的自传感生理控制器的关键和新颖之处在于，它能够在避免吸力的同时，通过使用差压和流量估计器，利用电机和磁轴承信号来调节LVAD输出，以响应心输出量的变化。该项目的具体目标是通过计算机模拟、体外和体内测试来设计、实施和演示MiTiHeart(R) LVAD输出的生理控制。具体来说，MiTi(R)的模拟循环系统（MCS）将被修改，以更准确地模拟左心室血流动力学，具有压差、流量和吸力回避目标函数的生理控制算法将在MiTiHeart(R) LVAD控制器中实现，并在MCS中进行评估。MCS和LVAD的电子模拟计算机模拟将进行更新和调整，以匹配测量数据，从而可以模拟额外控制算法和系统物理变化的评估，包括用人类心血管系统模型代替MCS模型。最后，将在宾夕法尼亚州立好时医学中心完成体内急性动物研究，以证明生理控制器在不进入抽吸的情况下调节LVAD输出的能力。计划以下具体目标：(1)设计并实现对MiTi(R) MCS的修改，通过改进左心室（LV）射血流量和压力的模拟，更准确地模拟左心室血流动力学。(2)修改第一阶段开发的MCS的数学模型，以接受包括生理控制算法在内的增强的LVAD性能模型。调整集成数学模型以反映MCS中测量的性能。使用优化模型评估LVAD和控制器对模拟变化的响应能力，首先在MCS模型中，然后在人类心血管系统（CVS）模型中。然后，将使用增强模型对MCS和CVS模型进行仿真，以评估LVAD和生理控制系统在各种条件下的性能，以验证控制器随着生理需求的变化而改变输出的能力，同时避免吸力。(3)在更新后的MCS中，通过体外测试评估生理控制系统性能、吸阻和泵压差和流量估计。在第一阶段开发的生理控制算法和架构将在dSpace数字控制硬件系统中实现。然后，控制系统将与MiTiHeart LVAD一起使用，在更新的MCS中表征和验证拟议的控制系统。将在不同的模拟心脏条件下进行MCS测试，以鼓励抽吸事件。(4)进行三次体内急性动物研究，以验证生理控制器的性能，包括估计压差和流量，以及检测和避免将对动物心脏CO进行药理学修饰的抽吸。公共卫生相关性：根据美国心脏协会b[1]的数据，每年大约有100万美国人死于心脏病，近470万美国人患有充血性心力衰竭（CHF），这是一种慢性疾病，至少有一个心脏腔不能很好地满足身体的需要。每年有50多万新发瑞士法郎病例，而近4万名心脏移植候选人只能获得2200颗供体心脏，因此迫切需要新的治疗选择，如机械循环辅助装置或心脏辅助泵[2]。早期发展的成功已经导致使用循环辅助短时间[2,3,4]，但需要新的发展，使这些心脏辅助装置的长时间使用成为可能。