Acute Biventricular Interaction in Pediatric Patients Implanted with Continuous Flow and Pulsatile Flow LVAD: A Simulation Study

Abstract

Left ventricular assist devices (LVADs) are used to bridge pediatric patients till transplantation. However, the LVADs effects on right ventricular (RV) function are controversial. This work aims at studying the ventricular interdependency in the presence of continuous (c-) and pulsatile (p-) flow LVAD in pediatric patients using a lumped parameter model including the representation of the septum. Five pediatric patients' data were used to simulate patients' baseline. The effects on LV and RV functions, energetics, preloads and afterloads of different c-LVAD speeds, p-LVAD rate, p-LVAD systole duration, p-LVAD filling and ejection pressures were simulated. c-LVAD and p-LVAD unload the LV decreasing the LV external work and improving the LV ventriculo-arterial coupling and these effects are more evident increasing the c-LVAD speed and the p-LVAD rate. Continuous-LVAD and p-LVAD decrease the RV afterload, increase the RV ejection fraction and improve the RV ventriculo-arterial coupling. The changes in RV function are inversely proportional to the degree of the interventricular septum leftward shift that increased by increasing the LVAD contribution. The study of the interventricular interaction could lead to the development of a dedicated algorithm to optimize LVAD setting in pediatric population.

The Use of Berlin Heart EXCOR VAD in Children Less than 10 kg: A Single Center Experience

“…Di Molfetta et al (2016) summarized with a simulation the effects of the LVAD implantation and the effects of the increased LVAD contribution using a lumped parameter model (Figure 1). Increasing the LVAD contribution a decrement of the LV preload and volumes and an increment of the arterial systemic mean pressure can be obtained together with an increment of the RV preload and RV volumes and a decrement of the pulmonary mean pressure.…”

Control of a Pediatric Pulsatile Ventricular Assist Device: A Hybrid Cardiovascular Model Study

“…(15,16) were used to set up the HCS and they were used as a basal condition with the aim of verifying three main issues: The patient's data are shown in the third column of Table 2. (15,16) were used to set up the HCS and they were used as a basal condition with the aim of verifying three main issues: The patient's data are shown in the third column of Table 2.…”

“…The results are therefore the output of the simulator, even if the model has been shown able to reproduce patient's data in different conditions (12,15), both in the case of pediatric and adult patients. The results are therefore the output of the simulator, even if the model has been shown able to reproduce patient's data in different conditions (12,15), both in the case of pediatric and adult patients.…”

“…Echocardiographic and hemodynamic data of one of the pediatric patients in Refs. (15,16) were used to set up the HCS and they were used as a basal condition with the aim of verifying three main issues: • whether for a given patient's HR, the choice of VAD rate (VADR) can influence left ventricular and right ventricular unloading/loading, and if so, how they depend on rates ratio (Rr) defined as VADR/HR; • whether the mutual interaction between the patient's HR and VADR can influence his hemodynamics; • whether different ventricular/circulatory conditions can influence the results.…”

“…The study was conducted on a model set up with a pediatric patient's basal condition at the onset of the assistance. The results are therefore the output of the simulator, even if the model has been shown able to reproduce patient's data in different conditions (12,15), both in the case of pediatric and adult patients. The main limiting hypothesis in these experiments is the assumption of constant and stable ventricular and circulatory conditions that might not be the case in a clinical environment.…”