Regurgitation is an abnormal condition happens when left ventricular assist devices (LVADs) operated at a low speed, which causes LVAD to fail to assist natural blood-pumping by heart and thus affects patients’ health. According to the degree of regurgitation, three LVAD’s regurgitation states were identified in this paper: no regurgitation, slight regurgitation and severe regurgitation. Regurgitation index (RI), which is presented based on the theory of dynamic closed cavity, is used to grade the regurgitation of LVAD. Numerical results showed that when patients are in exercising, resting and sleeping state, the critical speed between slight regurgitation and no regurgitation are 6 650 r/min, 7 000 r/min and 7 250 r/min, respectively, with corresponding RI of 0.401, 0.300 and 0.238, respectively. And the critical speed between slight regurgitation and severe regurgitation are 5 500 r/min, 6 000 r/min and 6 450 r/min, with corresponding RI of 0.488, 0.359 and 0.284 respectively. In addition, there is a negative relation correction between RI and rotational speed, so that grading the LVAD’s regurgitation can be achieved by determining the corresponding critical speed. Therefore, the detective parameter RI based on the signal of flow is proved to be able to grade LVAD’s regurgitation states effectively and contribute to the detection of LVAD’s regurgitation, which provides theoretical basis and technology support for developing a LVADs controlling system with high reliability.
Objective To optimize the hemodynamics of a disk blood pump in children. Method We used the computational fluid dynamics technology to simulate the flow in a pediatric blood pump numerically, and finally analyzed the results for deep study about the thrombosis and hemolysis produced in it, to improve the design according to the results of the flow field analysis. Results We calculated results between the flow rate and the pressure elevation at different rotational speed: 2 500 rpm, 3 000 rpm, and 4 000 rpm, respectively. Under each rotational speed, it was selected five different discharge outlet boundary conditions. The simulation results conformed to the experimental data. The increased pressure of the blood pump was effective. But the phenomenon of flow separation was increased the at blade surface in the low speed region. The maximum wall shear stress was maintained within 100 Pa. Conclusion The design of disc blood pump has a good fluid dynamic performance. And the flow line is fluent, the probability of thrombosis and hemolysis occurred is in the range of control. But the phenomenon of flow separation is appeared. There is a room to improve.
The implantation of a left ventricular assist device (LVAD) is an important therapeutic tool for patients with end-stage heart failure, which can either help patients transit to the heart transplantation stage or serve as destination therapy until the end of their lives. In recent years, the third generation of LVAD has evolved rapidly and several brands have been marketed both domestically and internationally. The number of LVAD implantations has been increasing and the long-term survival rate of implanted patients has improved, so this device has a broad development perspective. This article summarizes the current status, usage standards and precautions, and common complications after implantation of LVAD, as well as looks forward to the future development of LVAD, hoping to be helpful for researchers who are new to this field.
The implantation of left ventricular assist device (LVAD) has significantly improved the quality of life for patients with end-stage heart failure. However, it is associated with the risk of complications, with unplanned readmissions gaining increasing attention. This article reviews the influencing factors, prediction methods and models, and intervention measures for unplanned readmissions in LVAD patients, aiming to provide scientific guidance for clinical practice, assist healthcare professionals in accurately assessing patients' conditions, and develop rational care plans.
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.
Ventricular assist device can provide the heart with a nonload circumstance and improve hemodynamics and energy metabolism of ischemic myocardium.With ventricular assistance,not only multiple organ failure is improved but also cardiac function and myocardial injury are resumed. In recent years, studies found that ventricular assistance have an impact on the myocardial interstitium on its structural protein-typeⅠ,Ⅲcollagens and their metabolism conditioning systems.It reverse adverse myocardial remodeling and improve cardiac function by changing myocardial collagen content and distribution.
Objective To compare the early outcomes of domestic third-generation magnetically levitated left ventricular assist device (LVAD) with or without concomitant mitral valvuloplasty (MVP). Methods The clinical data of 17 end-stage heart failure patients who underwent LVAD implantation combined with preoperative moderate to severe mitral regurgitation in Fuwai Central China Cardiovascular Hospital from May 2018 to March 2023 were retrospectively analyzed. The patients were divided into a LVAD group and a LVAD+MVP group based on whether MVP was performed simultaneously, and early outcomes were compared between the two groups. Results There were 4 patients in the LVAD group, all males, aged (43.5±5.9) years, and 13 patients in the LVAD+MVP group, including 10 males and 3 females, aged (46.8±16.7) years. All the patients were successful in concomitant MVP without mitral reguragitation occurrence. Compared with the LVAD group, the LVAD+MVP group had a lower pulmonary artery systolic pressure and pulmonary artery mean pressure 72 h after operation, but the difference was not statistically different (P>0.05). Pulmonary artery systolic pressure was significantly lower 1 week after operation, as well as pulmonary artery systolic blood pressure and pulmonary artery mean pressure at 1 month after operation (P<0.01). There was no statistically significant difference in blood loss, operation time, cardiopulmonary bypass time, aortic cross-clamping time, mechanical ventilation time, or ICU stay time between the two groups (P>0.05). The differences in 1-month postoperative mortality, acute kidney injury, reoperation, gastrointestinal bleeding, and thrombosis and other complications between the two groups were not statistically significant (P>0.05). Conclusion Concomitant MVP with implantation of domestic third-generation magnetically levitated LVAD is safe and feasible, and concomitant MVP may improve postoperative hemodynamics without significantly increasing perioperative mortality and complication rates.
In China, more than half of heart failure patients are ischemic heart failure patients. And a large proportion of left ventricular assist device implantation patients are also ischemic heart failure patients. However, left ventricular assist device implantation in ischemic heart failure patients is facing with problems such as patient screening, coronary artery disease, small left ventricle, mitral insufficiency, and ventricular aneurysm. There are only a few retrospective studies with small sample sizes abroad trying to provide solutions to these problems. While there is a lack of systematic understanding of this issue in China. Therefore, we provide an overview of the application and progress of left ventricular assist devices in ischemic heart failure patients, aiming to help clinicians have a comprehensive understanding of this issue and provide some guidance.