Advances in Extracorporeal Support Technologies in Critically Ill Children

The field of pediatric heart failure is evolving, and the patient population is growing as survival after complex congenital heart surgeries is improving. Mechanical circulatory support and extracorporeal respiratory support in critically ill children has progressed to a mainstay rescue modality in pediatric intensive care medicine. The need for mechanical circulatory support is growing, since the number of organ donors does not meet the necessity. This article aims to review the current state of available mechanical circulatory and respiratory support systems in acute care pediatrics, with an emphasis on the literature discussing the challenges associated with these complex support modalities

Cumplimiento de los objetivos nutricionales durante el uso de Dispositivos de Asistencia Ventricular

Antecedentes: Los dispositivos de asistencia ventricular (VAD, sigla en inglés) se utilizan cada vez más para el manejo de la insuficiencia cardíaca descompensada en unidades de cuidados intensivos. El manejo nutricional es fundamental para la evolución clínica de estos pacientes. Objetivos: El objetivo fue evaluar en cuánto tiempo se puede alcanzar las necesidades nutricionales, utilizando distintas modalidades de apoyo nutricional, en pacientes que requirieron asistencia con VAD por insuficiencia cardíaca aguda en una clínica privada del país. Métodos: En una clínica privada se efectuó un estudio observacional retrospectivo analizando los datos clínicos relacionados al aporte nutricional de 12 pacientes que requirieron asistencia con VAD. Las vías de aporte nutricional evaluadas fueron la nutrición enteral (NE) y/o nutrición parenteral (NP). Se midió el tiempo de implementación del apoyo nutricional y su efecto se estimó por una valoración nutricional subjetiva y por la medición de indicadores de laboratorio. Además, se vigilaron las complicaciones asociadas al aporte nutricional. Resultados: El estudio incluyó a 12 pacientes. Los objetivos nutricionales se alcanzaron por completo en el 91% de los pacientes (n=11) en 3,7 ± 1 días después de iniciado el apoyo nutricional. En ese momento, 5 pacientes recibían NE exclusiva, 4 pacientes NP complementaria a la NE, 1 paciente NE complementaria a la alimentación oral y 1 paciente con vía oral. Al momento de alcanzar los requerimientos nutricionales ningún paciente tenía NP exclusiva. Conclusión: Concluimos que el apoyo nutricional precoz es factible y seguro en pacientes con VAD. Alcanzar los objetivos nutricionales es posible sin efectos adversos graves. Se necesitan estudios futuros para determinar el beneficio a largo plazo del apoyo nutricional agresivo para pacientes en estado crítico que requieren apoyo hemodinámico.

Background: Ventricular assist devices (VAD) are being used more frequently in patients with severe heart failure. Nutritional support is a critical factor for the outcome in these patients. Aim: to evaluate the time required and mode of nutritional support in patients with severe cardiac dysfunction being treated with VAD. Methods: 12 patients with VAD being treated in an intensive care unit were evaluated to determine the time and mode of support required to achieve adequate nutrition. Enteral and / or parenteral modes of nutritional support were used. The outcomes were evaluated by subjective appreciation, weight measurement and serum levels of albumin, pre-albumin and vitamin D. Results: Adequate nutritional support was achieved in 91% of patients a mean of 3 days after beginning of treatment (SD 1 day). At that time 5 patients were receiving only enteral nutrition, 4 patients enteral and parenteral nutrition, 1 patient enteral nutrition in addition to oral nutrition and 1 patients was receiving only oral nutrition. No patient was receiving only parenteral nutrition. Conclusion: early nutritional support is posible and safe in patients with an VAD. Further studies are needed to evaluate long term benefits of this strategy of nutritional support.

Effects of Left Ventricular Assist and Aortic Graft Angle on Aortic Valve: A Hemodynamic Study / 医用生物力学

Objective To investigate the effect of left ventricular assist device (LVAD) and aortic graft angle on hemodynamics of aortic valve. Methods Three models of aorta and aortic valve with 45°, 60° and 90° anastomosis angles between LVAD and aorta were constructed, and an in vitro pulsating table was built for in vitro experiments. Using particle image velocimetry (PIV) system, three moments in the cardiac cycle ( T1 systolic peak, T rapid closure, T3 diastolic peak), were selected to study the hemodynamic state of aortic valve. Results Velocity vector, vorticity and viscous shear stress were used to evaluate the effect of LVAD anastomosis angle on hemodynamics of aortic valve. During the period of rapid valve closure, with the increase of graft angle, the blood flow velocity near the valve wall, the average vorticity and the maximum viscous shear stress all increased. Conclusions When the graft angle is lower, the impact velocity of blood on the valve is smaller, and the shear force on the valve decreases, so that the valve is in a better hemodynamic environment. This study provides references for the selection of anastomotic angles in clinical operations.

Current status and progress of implantable left ventricular assist devices / 中国胸心血管外科临床杂志

@#Implantable left ventricular assist device (LVAD) has become an essential treatment for end-stage heart failure, and its effect has been continuously improved. In the world, magnetic levitation LVAD has become mainstream and is increasingly used as a destination treatment. China has also entered the era of ventricular assist device. The continuous improvement of the ventricular assist device will further improve the treatment effect. This article reviews the current situation and development trend of LVAD treatment in China and abroad.

A prospective multicenter clinical trial study of a domestic HeartCon third-generation magnetic and hydrodynamic levitation LVAD for the treatment of 50 cases of end-stage heart failure / 中华胸心血管外科杂志

Objective:To analyze and evaluate the safety and efficacy of a Chinese domestically manufactured Heart Con-type implantable third-generation magnetic and hydrodynamic levitation left ventricular assist device(LVAD) for the treatment of end-stage heart failure(ESHF), by reporting the results of eleven-center clinical trial on 50 cases.Methods:This study was a multicenter clinical trial, designed by means of prospective, multicenter and single-group target value. 50 subjects with ESHF were competitively enrolled and treated with HeartCon as the LVAD in eleven centers. The primary efficacy measure was survival, defined as either the subjects experiencing the transition to heart transplantation(HT) or myocardial recovery assisted by the device within 90 days, or as successfully assisted by the LVAD for full 90 days after implantation. The target survival rate was 60%, other observations included implantation success rate, mortality, pump failure needing replacement or emergency heart transplantation.Results:All enrolled 50 patients received LVAD implantation successfully, 46 survived with the pump for 90 days, 1 patient transitioned to heart transplantation, and 3 patients experienced pump thrombosis, within which 2 patients underwent pump replacement and continued to live with the pump for 90 days, and the other one received emergency heart transplantation. There were no dropout subjects. The survival rate at full 90 days after HeartCon implantation was 100%. The survival rates with pump in the full set analysis and the protocol set analysis were 96.00% and 95.92% respectively, which were higher than the target value of 60%. The differences were both statistically significant( P<0.05). Conclusion:The results of the multicenter clinical trial with the largest sample size in China using domestically manufactured third-generation LVAD has demonstrated that, HeartCon is a safe and effective LVAD to treat ESHF patients.

Current status and progress on the application of ventricular assist device / 器官移植

At present, heart transplantation is the most effective treatment for end-stage heart failure. Nevertheless, the shortage of donors is becoming an increasingly severe challenge. In recent years, rapid development of mechanical circulatory support technologies has provided multiple therapeutic options for patients with end-stage heart failure. As an important mechanical circulatory support device, ventricular assist device (VAD) are divided into durable VAD (dVAD) and temporary VAD (tVAD) according to the duration of assistance. dVAD shows application potential in bridging heart transplantation, destination therapy and bridge to decision. With technological progress and experience accumulation in clinical application, VAD is evolving towards the direction of more biocompatible, lighter, more bionic and intelligent. In this article, the development of VAD, application status at home and abroad and the overall application of VAD in our hospital were reviewed, aiming to provide reference for promoting the clinical application of VAD in China.

Progress and prospect of heart transplantation in children / 器官移植

Pediatric heart transplantation is the standard treatment for children complicated with refractory heart failure which is difficult to be treated by conventional surgery or drugs. At present, an increasing quantity of pediatric heart transplantation is being performed worldwide, whereas relevant experience is still lacking in China. In recent 10 years, significant progress has been achieved in pediatric heart transplantation. On one hand, the number of pediatric heart transplantation has been increased year by year. On the other hand, ABO-incompatible heart transplantation, application of ventricular assist device in children, and recipient-donor weight mismatch transplantation have been widely employed to resolve the shortage of donor heart in pediatric heart transplantation. However, relevant experience of pediatric heart transplantation is lacking in China, especially in understanding the indications of pediatric heart transplantation and the application of specific strategies for pediatric heart transplantation, etc. In this article, the development history, advances in therapeutic strategy and clinical prognosis of pediatric heart transplantation were reviewed.

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.

The ProtekDuo as Double Lumen Return Cannula in V?VP ECMO Configuration: A First?In?Man Method Description

We present a case of acute respiratory distress syndrome (ARDS) secondary to COVID?19 who required venovenous extracorporeal membrane oxygenation (V?V ECMO). Initially, a right ventricular assist device (RVAD), the ProtekDuo with an oxygenator, was placed in an outside heart center and the patient was transferred to us for ECMO management. Due to severe hypoxia, the configuration was later modified, and a 25 Fr femoral drainage cannula was inserted for venous drainage only. The arterial return tubing was spliced and using a Y?connector, arterialized blood was returned through both limbs of the ProtekDuo resulting in a significantly increased oxygenation and flow.

Role of transesophageal echocardiography in the intraoperative monitoring of left ventricular assist device implantation / 中华超声影像学杂志

Objective:To evaluate the clinical value of intraoperative transesophageal echocardiography (TEE) in monitoring left ventricular assist device (LVAD) implantation.Methods:Between March 2019 and November 2021, 23 consecutive patients from TEDA International Cardiovascular Hospital, including 21 cases with dilated cardiomyopathy, 1 case with myocardial noncompaction and 1 case with ischemic cardiomyopathy, underwent HeartCon blood pump, a type of third generation LVAD implantation for severe heart failure. TEE was preformed in all cases before and after cardiopulmonary bypass. The dimensions of left-sided and right-sided cardiac chamber, ventricular function, de-airing, interventricular septal position, inlet cannulae position and the function of device were observed and recorded during LVAD implantation. Paired t test was used for statistical analysis of left-sided and right-sided heart parameters in pre- and post-operative measurements. Results:The left heart was dilated significantly and coexistent with right heart enlargement in some degree before LVAD implantation in total 23 cases. More than moderate mitral regurgitation (MR) in 16 cases and less than moderate MR in 7 cases were present. Mild or trace aortic regurgitation (AR) existed in 13 cases. More than moderate tricuspid regurgitation (TR) in 4 cases and less than moderate TR in 16 cases were observed. Left atrial appendage thrombosis was detected in 2 cases. After LVAD implantation, TEE revealed that the left ventricular end-diastolic diameter reduced significantly (42 mm/m 2 vs 32.8 mm/m 2, P<0.05) and left ventricular ejection fraction increased accordingly (22.2% vs 34.0%, P<0.05). There were no significant differences in right ventricular diameter and fractional area change between pre- and post-operative findings(all P>0.05). The ratio of left ventricular inner diameter to right ventricular inner diameter (2.09 vs 1.69, P<0.05) decreased in total 23 cases after LVAD implantation.Interventricular septal position became neutral position instead of pre-oprative rightward position. The severity of MR decreased in varying degrees in total 23 cases after LVAD implantation. All patients underwent tricuspid valvuloplasty with residual mild regurgitation in 8 cases. Conclusions:HeartCon blood pump can effectively unload the left ventricle with sufficient cardiac output in patients with severe congestive heart failure. TEE plays a major role in the clinical decision making during LVAD implantation, which can evaluate pre-operative cardiac abnormalities, intra-operative air embolism, inlet cannulae position, cannulas patency and cardiac function, especially blood volume status and the balance between double ventricles, which is critical for optimal functioning of the device.

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.

Is pectoralis muscle index a risk factor for mortality in left ventricular assist device patients?

SUMMARY OBJECTIVE: We aimed to investigate whether sarcopenia measured from pectoralis muscles is a risk factor for long-term mortality in left ventricular assist device patients. METHODS: Patients aged >18 years implanted with a left ventricular assist device in a single center between 2013 and 2019 were retrospectively included. Patients without a thoracic computed tomography scan performed within 3 months of left ventricular assist device implantation and without computed tomography scans appropriate for pectoralis muscle measurement were excluded. Pectoralis muscle measurements were made on thoracic computed tomography slices, and pectoralis muscle indices were calculated for each patient. Sarcopenia was defined as being in the gender-specific lowest tertile of pectoralis muscle index. Survival was compared between patients with and without sarcopenia. RESULTS: The study was conducted on 64 left ventricular assist device patients who met the inclusion criteria. Notably, 21 (32.8%) of the study patients were sarcopenic. Diabetes mellitus and sarcopenia were more common in patients with 2-year mortality in our cohort. Patients with sarcopenia had a worse 2-year survival (p<0.001). Sarcopenia had an adjusted hazard ratio of 4.04 (95% confidence interval (CI) 1.36-12.02, p=0.012), while diabetes mellitus was associated with an adjusted hazard ratio of 3.14 (95%CI 1.17-8.39, p=0.023). CONCLUSION: Sarcopenia defined by low pectoralis muscle index increases the risk for 2-year mortality in left ventricular assist device patients.

Current status and progress of left ventricular assist device for end-stage heart failure / 中国胸心血管外科临床杂志

@#Although heart transplantation remains to be the optimal treatment for advanced heart failure, its use has been largely limited due to shortage of available donor organs. Over the past two decades, left ventricular assist device (LVAD) has been significantly modified in size, durability and hemocompatibility. In addition to the bridge to transplantation, LVAD has become an attractive alternative to heart transplantation for end-stage heart failure as destination therapy for unsuitable candidates. Although the performance of LVAD has been improving greatly in recent years, there are still great challenges in the management of device complications and low quality of life after implantation. This review will summarize the types of LVAD, indications for implantation, postoperative management and adverse events.

Effect of a delay mode of a ventricular assist device on hemodynamics of the cardiovascular system / 生物医学工程学杂志

The implantation of biventricular assist device (BiVAD) is more challenging than that of left ventricular assist device for the interaction in the process of multiple input and output. Besides, ventricular assist device (VAD) often runs in constant speed (CS) mode in clinical use and thus BiVAD also faces the problems of low pulsation and imbalance of blood volume between systemic circulation and pulmonary circulation. In this paper, a delay assist mode for a VAD by shortening the support time of VAD was put forward. Then, the effect of the delay mode on cardiac output, pulsation and the function of the aortic valve was observed by numerical method and the rules of hemodynamics were revealed. The research showed that compared with VAD supported in CS mode, the VAD using delay mode in systolic and diastolic period proposed in this paper could meet the demand of cardiac output perfusion and restore the function of the arterial valves. The open ratio of aortic valve (AV) and pulmonary valve (PV) increased with the time set in delay mode, and the blood through the AV/PV helped to balance the left and the right cardiac volume. Besides, delay mode also improved the pulsation index of arterial blood flow, which is conducive to the recovery of the ventricular pulse function of patients.

Short-term effect of HeartCon left ventricular assist device on the treatment of 20 adult patients with end-stage heart failure / 中华危重病急救医学

Objective:To investigate and evaluate the efficacy of HeartCon left ventricular assist device (LVAD) in the treatment of adult patients with end-stage heart failure (ESHF).Methods:A prospective and observational study was conducted. Patients with ESHF who underwent LVAD implantation in the department of cardiac surgery of Teda International Cardiovascular Hospital from September 2020 to August 2021 were selected. The left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) classification, N-terminal pro-B type natriuretic peptide (NT-proBNP), and six minute walk distance (6MWD) before operation and 90 days after operation were compared. The incidence of equipment failures and major adverse events within 90 days after operation were recorded.Results:A total of 20 patients with ESHF were included, with 15 males and 5 females. Patients' age ranged from 20 to 67 years old, with an average of (50.2±13.6) years old. The range of body weight was 49.8-106.1 kg, with an average of (67.9±15.5) kg, and the body surface area (BSA) was from 1.49 to 2.32 m 2, with an average of (17.6±0.22) m 2. The operation process of all the patients were successful. The length of hospital stay ranged from 33 to 90 days, and the average was 56.0 (42.8, 75.0) days. Complications within 90 days after operation as follows, 2 cases with pericardial tamponade (10%), 1 case with cerebral hemorrhage (5%), 1 case with mediastinum infection (5%), 3 cases with acute renal injury (AKI, 15%), 5 cases with gastrointestinal bleeding (25%). There were no mechanical failure of LVAD and hemolysis events, right ventricular failure (RVF), cerebral infarction and death occurred. Compared with preoperative, the LVEDD significantly decreased (mm: 67.50±13.98 vs. 77.40±9.73), LVEF significantly increased (%: 34.80±9.76 vs. 22.70±5.62), NT-proBNP significantly decreased (ng/L: 2 028.65±1 752.05 vs. 4 796.45±4 355.40), 6MWD significantly increased (m: 385.20±144.12 vs. 85.81±63.50) at 90 days after operation, and the differences were statistically significant (all P < 0.05). 18 cases (90%) of the 20 patients reached NYHA classification Ⅰ and 2 cases (10%) reached NYHA classification Ⅱ, which were significantly improved compared with those before surgery (all patients' NYHA classification were Ⅳ before surgery). Conclusion:HeartCon LVAD can effectively improve the life quality of patients with ESHF, which has been proved safe and effective in clinical trials, but its long-term effects and complications need further observation and study.

Flow Estimation Method of Centrifugal Left Ventricular Assist Device Based on Motor Parameters / 医用生物力学

Objective To study CH-VAD blood pump developed by CH Biomedical Inc., a method for estimating the real-time flow of blood pump was established by using the voltage, current, speed, duty cycle, and fluid viscosity as the input data. Methods The blood pump system was disassembled into two modules, the motor and the centrifugal pump. Firstly, the output torque of the motor was calculated according to the voltage, current, speed and duty cycle of the motor, then the relationship between flow and torque at different speeds and viscosities was tested through experiments, and a fitting model was established based on the experimental data. Results The fit goodness of Pump 1 and Pump 2 reached 0.982 6 and 0.982 9,respectively. The fitting parameters were used for verification. When the viscosity changed, the root mean square error for the estimated flow of Pump 1 and Pump 2 was 0.260 and 0.274 L/min, respectively. The fitting parameters and estimated results of the two blood pumps were in good agreement. The flow estimation method could follow the actual flow waveform in real time, and the accuracy of the estimated average flow was not affected by the pulsation. Conclusions The flow estimation method proposed in this paper is suitable for CH-VAD blood pumps. It can accurately estimate the flow of blood pumps in the range of speed 1 600-3 600 r/min, flow 0.4-8 L/min, viscosity 1.2-5 mPa·s, and can follow the flow waveform well under pulsating conditions.

Study on the synchronization of biventricular beats with the control mode of left ventricular assist device / 生物医学工程学杂志

Right ventricular (RV) failure has become a deadly complication of left ventricular assist device (LVAD) implantation, for which desynchrony in bi-ventricular pulse resulting from a LVAD is among the important factor. This paper investigated how different control modes affect the synchronization of pulse between LV (left ventricular) and RV by numerical method. The numerical results showed that the systolic duration between LV and RV did not significantly differ at baseline (LVAD off and cannula clamped) (48.52%

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.

Early outcomes of heart transplantation in critical patients: single center experience of Fuwai Hospital / 器官移植

Objective To analyze the early outcomes of heart transplantation in critical patients and its significance in donor allocation decision. Methods Clinical data of 449 recipients undergoing heart transplantation were retrospectively analyzed. According to preoperative status, all patients were divided into the critical status group (n=64) and general status group (n=385). The incidence of critical status was summarized. Clinical data of recipients were statistically compared between two groups. Postoperative survival and causes of death in recipients between two groups were analyzed. Perioperative results of critical recipients undergoing different mechanical circulation support as a bridge to heart transplantation were compared. Results Critical patients accounted for 14.3% of the total number of transplant recipients. The proportion of critical patients gradually increased in recent 5 years. Compared with the general status group, the recipients in critical status group had a lower proportion of smoking history, a higher proportion of cardiac surgery history, a higher serum level of creatinine, and a higher proportion of primary diseases of heart failure before heart transplantation(all P≤0.01). The proportion of undergoing mechanical circulation support was higher, the incidence of complications was higher, the stay time in intensive care unit (ICU) was longer and the in-hospital fatality was higher after heart transplantation in the critical status group (all P≤0.01). The 1-year survival rate of recipients in critical status group was significantly lower than that in general status group (83% vs. 95%, P < 0.01). The fatality of recipients due to infection and multiple organ failure in critical status group was higher than that in general status group. Among 64 critical recipients, 1 recipient received ventilator alone, and 63 recipients underwent mechanical circulation support devices as a bridge to heart transplantation. Among them, intra-aortic balloon pump (IABP) alone was applied in 49 cases (77%), 8 cases (13%) of extracorporeal membrane oxygenation (ECMO) combined with IABP, 4 cases (6%) of ECMO alone, and 2 cases (3%) of left ventricular assist device (LVAD) alone. Critical patients who received preoperative ECMO and ECMO combined with IABP bridging to heart transplantation have a higher proportion of postoperative complications, a longer ICU stay time, a longer mechanical ventilation time, and a higher proportion of hospital deaths. Conclusions The overall prognosis of critical patients undergoing heart transplantation is relatively poor. Effective preoperative management may reverse the high-risk status of critical patients in a certain extent. The limited quantity of donor heart should be allocated to the most urgent patients who can obtain the greatest benefit from heart transplantation.

Value of transthoracic echocardiography to monitor and evaluate aortic insufficiency after implantation of left ventricular assist device / 中国胸心血管外科临床杂志

@#Objective    To explore the value of transthoracic echocardiography (TTE) to monitor and evaluate aortic insufficiency (AI) within one year after the implantation of the left ventricular assist device (LVAD). Methods    We retrospectively collected and analyzed the TTE data of 12 patients who received LVAD implantation from 2018 to 2020 in our hospital. All patients were males, with an average age of 43.3±8.6 years. We analyzed temporal changes in the aortic annulus (AA), aortic sinus (AoS), ascending aorta (AAo), the severity of AI and the opening of aortic valve before operation and 1 month, 3 months, 6 months and 12 months after LVAD implantation. Results    All 12 patients survived within 1 year after LVAD implantation. One patient was bridged to heart transplantation 6 months after implantation, and two patients did not receive TTE after 3 and 6 months. Compared to pre-implantation, AoS increased at 1 month after implantation (31.58±5.09 mm vs. 33.83±4.69 mm). The inner diameters of AA, AoS and AAo increased at 3, 6 and 12 months after LVAD implantation compared to pre-implantation (P<0.05), but all were within the normal range except for one patient whose AoS slightly increased before operation. After LVAD pump speed was adjusted, the opening of aortic  valve improved. The severity of AI increased at 6 and 12 months after LVAD implantation compared to pre-implantation, and increased at 12 months compared to 6 months after LVAD implantation (P<0.05). Conclusion    TTE can evaluate aortic regurgitation before and after LVAD implantation and monitor the optimization and adjustment of LVAD pump function, which has a positive impact on the prognosis after LVAD implantation.