Application of ECMO in pediatric heart transplantation / 器官移植

Extracorporeal membrane oxygenation (ECMO) could pump the blood from human veins to the outside of the body, oxygenate the red blood cells in an artificial environment and then return them back into the body. ECMO could replace the heart and lungs to complete gas exchange and systemic blood perfusion in patients with severe cardiopulmonary insufficiency, which also plays an important role in the field of heart transplantation. Besides circulatory support treatment after heart transplantation, ECMO may also be used to prolong the waiting time for heart transplantation in patients with respiratory and circulatory failure before operation, as a bridging therapy for heart transplantation. However, at present, the application of ECMO in pediatric heart transplantation still exist challenges, such as high perioperative mortality and difficulty in determining the timing of treatment, etc. In this article, the development history of ECMO application in pediatric heart transplantation, use of ECMO before and after pediatric heart transplantation, ECMO-related complications in children, and application of ventricular assist device (VAD) in pediatric heart transplantation were briefly reviewed, aiming to provide reference for promoting the application of ECMO in pediatric heart transplantation.

Simulation Experimental Study on Mock Circulation System / 医用生物力学

Objective To study the mock circulation system (MCS) which can accurately reproduce the human hemodynamic environment for in vitro test in the development of artificial organs such as ventricular assist devices (VAD) and artificial heart-lung machine.Methods A double-heart MCS including the systemic and pulmonary circulation was established, which basically covered the main physiological characteristics and functions of the cardiovascular system. The simulation of valves and arteries were proposed with a new way made of silicone material. The MCS could simulate a variety of physiological environments such as normal human body, heart failure, valvular diseases, arteriosclerosis and peripheral obstruction changes by adjusting the control system parameters or structural parameters.The sensor and control system were used to realize the real-time display, control and data preservation of pressure and flow.Results The MCS could simulate the hemodynamic environment of normal human body and a variety of diseases, which were basically consistent with the actual human condition. The new valve and artery model reduced pressure fluctuations in a much better way. The HeartCon VAD of RocketHeart was connected to the experimental platform under simulated state of heart failure, and the hemodynamic environment (aortic pressure, left atrial pressure, cardiac output, etc.) could all be recovered to the normal range.Conclusions The MCS can accurately reproduce the hemodynamic environment of body and pulmonary circulation under a variety of physiological states, and provide an effective experimental platform for the performance test and control strategy design of artificial organs such as VAD. At the same time, the simulation method of making valves and arteries with silicone material can also be further improved in MCS.

Evaluation on Mechanical Damage of vWF Induced by Shear Stress in BPX-80 Centrifugal Blood Pump / 医用生物力学

Objective To evaluate the damage of von Willebrand factor (vWF) induced by shear stress in BPX-80 centrifugal blood pump, and determine whether it can be used as a reference pump for vWF damage research. Methods An in vitro hemolysis test platform was established according to the ASTM standards. The BPX-80 centrifugal blood pump was tested for 8 hours by using fresh porcine blood. The hemolysis level and vWF damage of hourly blood samples were then evaluated and compared with the static control group. ResultsThe hemolysis index of BPX-80 was stable and low during the test; vWF polymer with high molecular weight had a small amount of degradation, and showed no significant difference compared with the static control group; there was no significant change in the concentration of vWF antigen, which was basically consistent with the trend of the static control group. Conclusions BPX-80 centrifugal blood pump has good blood compatibility and can be used as the reference pump for vWF damage and hemolysis evaluation, thereby providing guidance for the design and optimization of new blood pumps.

A Review on Mock Circulatory Systems for in vitro Hemodynamic Performance Evaluation of Ventricular Assist Devices / 医用生物力学

Mock circulatory system (MCS) is an experimental platform for simulating hemodynamic performance of human circulatory system, and has been widely used in in-vitro hemodynamic performance evaluation of passive devices such as ventricular assist devices (VADs), artificial valves, as well as hemodynamic responses of mock circulation loop. MCSs are capable of simulating various physiological conditions, including health, exercise, and heart failure, by adjusting drive element of heart simulator and lumped-parameter element of vasculature components. Since 1 960 s, the research and development target of MSCs has evolved from meeting the basic performance evaluation requirement of VADs and mechanical valve to mimicking local hemodynamic characteristics in vital organs. This review summarizes the design principles, system construction of MCSs as well as its research progress and future prospects.

In vitro simulation experimental study of a fully magnetically levitated ventricular assist device based on mock circulatory system / 医用生物力学

Objective To investigate the circulatory supporting effect of the third generation fully magnetically levitated China Heart ventricular assist device (CH-VAD) under heart failure (HF) condition.Methods An in vitro mock circulatory system (MCS) was developed.This system could simulate a healthy adult under resting state and a patient with heart failure,and incorporate the CH-VAD to evaluate the assisting performance under continuous flow mode.Furthermore,CH-VAD was equipped with a pulsatile flow controller and its initial performance was accessed.The pulsatile mode was obtained by using sinusoidal velocity waveform of the pump which synchronized the CH-VAD with the ventricle simulator of the MCS.Results CH-VAD under continuous flow mode could recover the hemodynamic parameters (arterial pressure and cardiac output) under HF condition to normal range.Preliminary pulsatile test results showed that amplitude of current pulse speed had a minor influence on the hemodynamic performance.CH-VAD under continuous flow and pulsatile flow mode could obtain comparable mean arterial pressure,systolic arterial pressure,diastolic arterial pressure and mean flow.Conclusions CH-VAD can generate a certain degree of speed pulse via appropriate pulsatility control,so as to provide sufficient support on ventricular function.Further optimization on pulsatile controller of CH-VAD is required to conform to natural physiology.The developed MCS can be utilized as an effective and controllable in vitro platform for design,optimization and verification of VADs or other mechanical circulatory support devices.

In vitro simulation experimental study of a fully magnetically levitated ventricular assist device based on mock circulatory system / 医用生物力学

Objective To investigate the circulatory supporting effect of the third generation fully magnetically levitated China Heart ventricular assist device (CH-VAD) under heart failure (HF) condition.Methods An in vitro mock circulatory system (MCS) was developed.This system could simulate a healthy adult under resting state and a patient with heart failure,and incorporate the CH-VAD to evaluate the assisting performance under continuous flow mode.Furthermore,CH-VAD was equipped with a pulsatile flow controller and its initial performance was accessed.The pulsatile mode was obtained by using sinusoidal velocity waveform of the pump which synchronized the CH-VAD with the ventricle simulator of the MCS.Results CH-VAD under continuous flow mode could recover the hemodynamic parameters (arterial pressure and cardiac output) under HF condition to normal range.Preliminary pulsatile test results showed that amplitude of current pulse speed had a minor influence on the hemodynamic performance.CH-VAD under continuous flow and pulsatile flow mode could obtain comparable mean arterial pressure,systolic arterial pressure,diastolic arterial pressure and mean flow.Conclusions CH-VAD can generate a certain degree of speed pulse via appropriate pulsatility control,so as to provide sufficient support on ventricular function.Further optimization on pulsatile controller of CH-VAD is required to conform to natural physiology.The developed MCS can be utilized as an effective and controllable in vitro platform for design,optimization and verification of VADs or other mechanical circulatory support devices.

In vitro simulation experimental study of a fully magnetically levitated ventricular assist device based on mock circulatory system / 医用生物力学

Objective To investigate the circulatory supporting effect of the third generation fully magnetically levitated China Heart ventricular assist device (CH-VAD) under heart failure (HF) condition.Methods An in vitro mock circulatory system (MCS) was developed.This system could simulate a healthy adult under resting state and a patient with heart failure,and incorporate the CH-VAD to evaluate the assisting performance under continuous flow mode.Furthermore,CH-VAD was equipped with a pulsatile flow controller and its initial performance was accessed.The pulsatile mode was obtained by using sinusoidal velocity waveform of the pump which synchronized the CH-VAD with the ventricle simulator of the MCS.Results CH-VAD under continuous flow mode could recover the hemodynamic parameters (arterial pressure and cardiac output) under HF condition to normal range.Preliminary pulsatile test results showed that amplitude of current pulse speed had a minor influence on the hemodynamic performance.CH-VAD under continuous flow and pulsatile flow mode could obtain comparable mean arterial pressure,systolic arterial pressure,diastolic arterial pressure and mean flow.Conclusions CH-VAD can generate a certain degree of speed pulse via appropriate pulsatility control,so as to provide sufficient support on ventricular function.Further optimization on pulsatile controller of CH-VAD is required to conform to natural physiology.The developed MCS can be utilized as an effective and controllable in vitro platform for design,optimization and verification of VADs or other mechanical circulatory support devices.

In vitro simulation experimental study of a fully magnetically levitated ventricular assist device based on mock circulatory system / 医用生物力学

Objective To investigate the circulatory supporting effect of the third generation fully magnetically levitated China Heart ventricular assist device (CH-VAD) under heart failure (HF) condition. Methods An in vitro mock circulatory system (MCS) was developed. This system could simulate a healthy adult under resting state and a patient with heart failure, and incorporate the CH-VAD to evaluate the assisting performance under continuous flow mode. Furthermore, CH-VAD was equipped with a pulsatile flow controller and its initial performance was accessed. The pulsatile mode was obtained by using sinusoidal velocity waveform of the pump which synchronized the CH-VAD with the ventricle simulator of the MCS. Results CH-VAD under continuous flow mode could recover the hemodynamic parameters (arterial pressure and cardiac output) under HF condition to normal range. Preliminary pulsatile test results showed that amplitude of current pulse speed had a minor influence on the hemodynamic performance. CH-VAD under continuous flow and pulsatile flow mode could obtain comparable mean arterial pressure, systolic arterial pressure, diastolic arterial pressure and mean flow. Conclusions CH-VAD can generate a certain degree of speed pulse via appropriate pulsatility control, so as to provide sufficient support on ventricular function. Further optimization on pulsatile controller of CH-VAD is required to conform to natural physiology. The developed MCS can be utilized as an effective and controllable in vitro platform for design, optimization and verification of VADs or other mechanical circulatory support devices.

Mechanical Circulatory Support for Advanced Heart Failure / 대한내과학회지

Patients with end-stage heart failure or cardiogenic shock experience unacceptably high mortality despite advances in treatment made over the past 50 years. The effects of vasoactive drugs used to manage cardiogenic shock may be limited, being highly dependent on "remaining" heart function. Mechanical circulatory support improves cardiac output independent of heart function. Intra-aortic balloon pumps (IABPs) and extracorporeal membrane oxygenation (ECMO) are the devices most commonly used in Korea. Despite frequent use, the utility of IABPs in acute myocardial patients remains controversial, whereas ECMO affords sufficient systemic perfusion pressure to reverse end-organ dysfunction. Both can only be used as acute treatments, thus as a bridge-to-recovery or a bridge-to-transplantation. Percutaneous left ventricular assist devices (LVADs) such as TandemHeart(R) and Impella are not in use in Korea. Implanted LVADs improve long-term outcomes and may also serve as destination therapies. In the present manuscript, we briefly review percutaneous and implantable devices currently used in Korea for the management of advanced heart failure.

Infecciones asociadas a dispositivos de soporte circulatorio mecánico / Ventricular assist device-related infections

El dispositivo de asistencia ventricular asistida (DAV) se utiliza como terapéutica final o puente al trasplante cardíaco. La tasa de complicaciones infecciosas asociada a este dispositivo es elevada. La experiencia con este tipo de complicación en pediatría es escasa. Objetivo: conocer las características clínicas, microbiológicas y de evolución de pacientes con DAV. Material y métodos: pacientes internados en el Hospital Garrahan desde marzo del 2006 a marzo 2014 con DAV. Estudio retrospectivo, descriptivo. Se analizaron: edad, sexo, tipo de enfermedad de base, características clínicas, microbiológicas y de evolución de los pacientes con DAV. Resultados: se incluyeron 33 pacientes. La mediana de edad fue 79 meses (rango:13-133). La indicación de colocación del DAV fue miocardiopatía dilatada en el 81.8% (27). Los días acumulados de uso del DAV fue de 4.638 días. Diecisiete pacientes (51.5%) presentaron 23 episodios de infección. La infección pericánula se presentó 10 casos (43.4%), bacteriemias primarias en 4 (17.4%), bacteriemia asociada a catéter de corta permanencia 5 (21.7%), mediastinitis 3 (13%) y un caso de sepsis (4.3%). Los microorganismos prevalentes fueron los cocos gram positivos. Fallecieron 12 pacientes en DAV a la espera del trasplante, uno de ellos con sepsis y mediastinitis por S. aureus meticilino sensible. Conclusiones: La infección asociada a DAV fue frecuente en nuestros pacientes y dentro de ellas la infección pericánula fue la más común. Los cocos gran positivos fueron los microorganismos predominantes. Los pacientes con mayor tiempo de permanencia del DAV presentaron varios episodios de infección. Las infecciones asociadas al DAV no impidieron el éxito del trasplante cardíaco (AU)