scholarly journals Stochastic Modeling and Dynamic Analysis of the Cardiovascular System with Rotary Left Ventricular Assist Devices

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Jeongeun Son ◽  
Dongping Du ◽  
Yuncheng Du
Keyword(s):  
Heart Failure ◽  
Cardiac Output ◽  
Pump Power ◽  
Aortic Valve ◽  
Cardiovascular System ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Left Ventricular Assist

Left ventricular assist devices (LVADs) have been used for end-stage heart failure patients as a therapeutic option. The aortic valve plays a critical role in heart failure and its treatment with a LVAD. The cardiovascular-LVAD model is often used to investigate the physiological demands required by patients and predict the hemodynamic of the native heart supported with a LVAD. As it is a “bridge-to-recovery” treatment, it is important to maintain appropriate and active dynamics of the aortic valve and the cardiac output of the native heart, which requires that the LVAD pump be adjusted so that a proper balance between the blood contributed through the aortic valve and the pump is maintained. In this paper, we investigate how the pump power of the LVAD pump can affect the dynamic behaviors of the aortic valve for different levels of activity and different severities of heart failure. Our objective is to identify a critical value of the pump power (i.e., breakpoint) to ensure that the LVAD pump does not take over the pumping function in the cardiovascular-pump system and share the ejected blood with the left ventricle to help the heart to recover. In addition, the hemodynamic often involves variability due to patients’ heterogeneity and the stochastic nature of the cardiovascular system. The variability poses significant challenges to understanding dynamic behaviors of the aortic valve and cardiac output. A generalized polynomial chaos (gPC) expansion is used in this work to develop a stochastic cardiovascular-pump model for efficient uncertainty propagation, from which it is possible to rapidly calculate the variance in the aortic valve opening duration and the cardiac output in the presence of variability. The simulation results show that the gPC-based cardiovascular-pump model is a reliable platform that can provide useful information to understand the effect of the LVAD pump on the hemodynamic of the heart.

scholarly journals Advances in Hemodynamic Analysis in Cardiovascular Diseases Investigation of Energetic Characteristics of Adult and Pediatric Sputnik Left Ventricular Assist Devices during Mock Circulation Support

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Alexander A. Pugovkin ◽  
Aleksandr G. Markov ◽  
Sergey V. Selishchev ◽  
Leonie Korn ◽  
Marian Walter ◽  
...  
Keyword(s):  
Heart Failure ◽  
Aortic Valve ◽  
Left Ventricular ◽  
Operating Conditions ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Mock Circulation ◽  
Left Ventricular Assist

The need to simulate the operating conditions of the human body is a key factor in every study and engineering process of a bioengineering device developed for implantation. In the present paper, we describe in detail the interaction between the left ventricle (LV) and our Sputnik left ventricular assist devices (LVADs). This research aims to evaluate the influence of different rotary blood pumps (RBPs) on the LV depending on the degree of heart failure (HF), in order to investigate energetic characteristics of the LV-LVAD interaction and to estimate main parameters of left ventricular unloading. We investigate energetic characteristics of adult Sputnik 1 and Sputnik 2 LVADs connected to a hybrid adult mock circulation (HAMC) and also for the Sputnik pediatric rotary blood pump (PRBP) connected to a pediatric mock circulation (PMC). A major improvement of the LV unloading is observed during all simulations for each particular heart failure state when connected to the LVAD, with sequential pump speed increased within 5000–10000 rpm for adult LVADs and 6000–13000 rpm for PRBP with 200 rpm step. Additionally, it was found that depending on the degree of heart failure, LVADs influence the LV in different ways and a significant support level cannot be achieved without the aortic valve closure. Furthermore, this study expands the information on LV-LVAD interaction, which leads to the optimization of the RBP speed rate control in clinics for adult and pediatric patients suffering from heart failure. Finally, we show that the implementation of control algorithms using the modulation of the RBP speed in order to open the aortic valve and unload the LV more efficiently is necessary and will be content of further research.

Abstract 225: Frequency and Assessment of Poor Global Outcome in Patients with Left Ventricular Assist Devices

2015 ◽  
Vol 8 (suppl_2) ◽  
Author(s):  
Timothy J Fendler ◽  
Michael E Nassif ◽  
Kevin F Kennedy ◽  
John A Spertus ◽  
Shane J LaRue ◽  
...  
Keyword(s):  
Heart Failure ◽  
Nyha Class ◽  
Left Ventricular ◽  
Advanced Heart Failure ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Bridge To Transplant ◽  
Patient Reported ◽  
Left Ventricular Assist

Background: Left ventricular assist device (LVAD) therapy can improve survival and quality of life in advanced heart failure (HF), but some patients may still do poorly after LVAD. Understanding the likelihood of experiencing poorer outcomes after LVAD can better inform patients and calibrate their expectations. Methods: We analyzed patients receiving LVAD therapy from January 2012 to October 2013 at a single, high-volume, high-acuity center. We defined a poor global outcome at 1 year after LVAD as the occurrence of death, disabling stroke (precluding transplant), poor patient-reported health status (most recent KCCQ at 3, 6, or 12 months < 45, corresponding to NYHA class IV), or recurrent HF (≥2 HF readmissions post-implant). We compared characteristics of those with and without poor global outcome. Results: Among 164 LVAD recipients who had 1-year outcomes data, mean age was 56, 76.7% were white, 20.9% were female, and 85.9% were INTERMACS Profile 1 or 2 (cardiogenic shock or declining despite inotropes). Poor global outcome occurred in 58 (35.4%) patients at 1 year, of whom 37 (63.8%) died, 17 (29.3%) had a most recent KCCQ score < 45, 3 (5.2%) had ≥2 HF readmissions, and 1 (1.7%) had a disabling stroke (Figure). Eight of the patients who died also experienced one of the three other poor outcomes prior to death. Patients who experienced a poor global outcome were more likely to be designated for destination therapy (46.4% vs. 23.6%, p=0.01) than bridge to transplant, have longer index admissions (median [IQR]: 39 [24, 57] days vs. 25 [18, 35] days, p=0.003), and have major GI bleeding (44.2% vs. 27.7%, p=0.056), and were less likely to undergo LVAD exchange (0% vs. 12.3%, p=0.004). Conclusion: In this large, single-center study assessing global outcome after LVAD implantation, we found that about a third of all patients had experienced a poor global outcome at 1 year. While LVAD therapy remains life-saving and the standard of care for many patients with advanced heart failure, these findings could help guide discussions with eligible patients and families. Future work should compare patients’ pre-LVAD expectations with likely outcomes and create risk models to estimate the probability of poorer outcomes for individual patients using pre-procedural factors.

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