Numerical Study of Blood Flow at the End-to-Side Anastomosis of a Left Ventricular Assist Device for Adult Patients

2008 ◽  
Author(s):  
Ning Yang ◽  
Steven Deutsch ◽  
Eric G. Paterson ◽  
Keefe B. Manning
Keyword(s):  
Blood Flow ◽  
Left Ventricular ◽  
Operating Conditions ◽  
Adult Patients ◽  
Ventricular Assist Devices ◽  
Shear Stresses ◽  
Ventricular Assist ◽  
Outflow Cannula ◽  
The Impact ◽  
Secondary Vessels

Ventricular assist devices (VADs) have been used for years in adult patients with end-stage heart failure, during bridge-to-transplant, and they have recently shown promise in aiding in myocardial recovery [1]. While the fluid mechanics within VADs has been studied extensively [2], an area which must be more adequately addressed is the outflow cannula attached as an end-to-side anastomosis to the aorta. This attachment may lead to unnaturally high and low shear stresses, turbulence, flow separation, and stagnant flows. As a result, platelet activation and thrombus formation may occur. May-Newman et al. [3] developed a laminar, continuous, computational fluid dynamics (CFD) model to study how different outflow cannula anastomoses affect flow patterns in an adult aortic model. Turbulent flows, however, were not considered. The effects of the anastomosis on the flows in the secondary vessels were neglected as well. There is a lack of detailed description of the flow field across the cannulated adult aorta based on different VAD outflow cannula configurations and operating conditions. As a result, we have developed a comprehensive model to simulate turbulent blood flow in three-dimensional models of the cannulated adult aorta under continuous flow conditions and to study the impact of the secondary vessels on the aortic arch.

scholarly journals Impact of Obesity on Heart Transplantation Outcomes

2021 ◽  
Vol 10 (23) ◽  
Author(s):  
Fouad Chouairi ◽  
Aidan Milner ◽  
Sounok Sen ◽  
Avirup Guha ◽  
James Stewart ◽  
...  
Keyword(s):  
Heart Transplantation ◽  
Organ Procurement ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Allocation System ◽  
Increased Risk ◽  
The Impact ◽  
Transplantation Outcomes

Background Patients with obesity and advanced heart failure face unique challenges on the path to heart transplantation. There are limited data on waitlist and transplantation outcomes in this population. We aimed to evaluate the impact of obesity on heart transplantation outcomes, and to investigate the effects of the new organ procurement and transplantation network allocation system in this population. Methods and Results This cohort study of adult patients listed for heart transplant used the United Network for Organ Sharing database from January 2006 to June 2020. Patients were stratified by body mass index (BMI) (18.5–24.9, 25–29.9, 30–34.9, 35–39.9, and 40–55 kg/m 2 ). Recipient characteristics and donor characteristics were analyzed. Outcomes analyzed included transplantation, waitlist death, and posttransplant death. BMI 18.5 to 24.9 kg/m 2 was used as the reference compared with progressive BMI categories. There were 46 645 patients listed for transplantation. Patients in higher BMI categories were less likely to be transplanted. The lowest likelihood of transplantation was in the highest BMI category, 40 to 55 kg/m 2 (hazard ratio [HR], 0.19 [0.05–0.76]; P =0.02). Patients within the 2 highest BMI categories had higher risk of posttransplantation death (HR, 1.29; P <0.001 and HR, 1.65; P <0.001, respectively). Left ventricular assist devices among patients in obese BMI categories decreased after the allocation system change ( P <0.001, all). After the change, patients with obesity were more likely to undergo transplantation (BMI 30–35 kg/m 2 : HR, 1.31 [1.18–1.46], P <0.001; BMI 35–55 kg/m 2 : HR, 1.29 [1.06–1.58]; P =0.01). Conclusions There was an inverse relationship between BMI and likelihood of heart transplantation. Higher BMI was associated with increased risk of posttransplant mortality. Patients with obesity were more likely to undergo transplantation under the revised allocation system.

scholarly journals Analysis of Operating Modes for Left Ventricle Assist Devices via Integrated Models of Blood Circulation

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1331 ◽  
Author(s):  
Sergey Simakov ◽  
Alexander Timofeev ◽  
Timur Gamilov ◽  
Philip Kopylov ◽  
Dmitry Telyshev ◽  
...  
Keyword(s):  
Left Ventricular ◽  
Operating Conditions ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Lumped Model ◽  
Assist Devices ◽  
Operating Modes ◽  
Mock Circulation

Left ventricular assist devices provide circulatory support to patients with end-stage heart failure. The standard operating conditions of the pump imply limitations on the rotation speed of the rotor. In this work we validate a model for three pumps (Sputnik 1, Sputnik 2, Sputnik D) using a mock circulation facility and known data for the pump HeartMate II. We combine this model with a 1D model of haemodynamics in the aorta and a lumped model of the left heart with valves dynamics. The model without pump is validated with known data in normal conditions. Simulations of left ventricular dilated cardiomyopathy show that none of the pumps are capable of reproducing the normal stroke volume in their operating ranges while complying with all criteria of physiologically feasible operation. We also observe that the paediatric pump Sputnik D can operate in the conditions of adult circulation with the same efficiency as the adult LVADs.

scholarly journals Corrigendum to “Effects of Sevoflurane and Propofol on Organ Blood Flow in Left Ventricular Assist Devices in Pigs”

2016 ◽  
Vol 2016 ◽  
pp. 1-1 ◽  
Author(s):  
Paloma Morillas-Sendín ◽  
Emilio Delgado-Baeza ◽  
María Jesús Delgado-Martos ◽  
Mónica Barranco ◽  
Juan Francisco Del Cañizo ◽  
...  
Keyword(s):  
Blood Flow ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Organ Blood Flow ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist

Endothelial Function in Patients With Continuous-Flow Left Ventricular Assist Devices

Angiology ◽  
2020 ◽  
Vol 72 (1) ◽  
pp. 9-15
Author(s):  
Pavel Poredos ◽  
Mateja K. Jezovnik ◽  
Rajko Radovancevic ◽  
Igor D. Gregoric
Keyword(s):  
Heart Failure ◽  
Blood Flow ◽  
Shear Stress ◽  
Continuous Flow ◽  
Tissue Perfusion ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Left Ventricular Assist

The endothelium plays a crucial role in maintaining cardiovascular homeostasis. Shear stress generated by flowing blood regulates the release of substances that provide adequate tissue perfusion. The extent of damage to endothelial cells depends on locally disturbed shear stress caused by the deteriorated flow. Patients with heart failure have reduced cardiac output, which results in reduced blood flow and negative shear stress. Reduced shear stress also affects microcirculation and reduces tissue perfusion. Consequently, the production of free oxygen radicals is increased and bioavailability of nitric oxide is additionally decreased. Therefore, endothelial dysfunction is involved in the progression of heart failure and cardiovascular events. Left ventricular assist devices (LVAD) are used for the treatment of patients with advanced heart failure. Older pulsatile flow LVADs were mostly substituted by continuous-flow LVADs (cf-LVADs). Despite the advantages of the cf-LVADs, the loss of pulsatility leads to different complications on the micro- and macrovascular levels. One of the pathogenetic mechanisms of cardiovascular complications with cf-LVADs may be endothelial dysfunction, which after the implantation of the device does not improve and may even deteriorate. In contrast, the pulsatile pattern of LVADs on blood flow could preserve endothelial function.

Myocardial recovery: a focus on the impact of left ventricular assist devices

2014 ◽  
Vol 12 (5) ◽  
pp. 589-600 ◽  
Author(s):  
M Scott Halbreiner ◽  
Vincent Cruz ◽  
Randall Starling ◽  
Edward Soltesz ◽  
Nicholas Smedira ◽  
...  
Keyword(s):  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Myocardial Recovery ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist ◽  
The Impact

Impact of Previous Sternotomy on Outcome after Left Ventricular Assist Device Implantation

2019 ◽  
Vol 67 (03) ◽  
pp. 183-190 ◽  
Author(s):  
Konstantin Zhigalov ◽  
Marcin Szczechowicz ◽  
Ahmed Mashhour ◽  
Sabreen Mkalaluh ◽  
Maxim Isaev ◽  
...  
Keyword(s):  
Ventricular Assist Device ◽  
Study Groups ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Assist Device ◽  
Ventricular Assist ◽  
Mortality And Morbidity ◽  
Left Ventricular Assist ◽  
The Impact

Background The main purpose of this article is to investigate the impact of previous sternotomy (PS) on the outcome of three different left ventricular assist devices (LVAD). Methods Between June 2007 and February 2018, a total of 121 patients received HeartMate II (60.3%), HeartWare (12.4%), or HeartMate III (27.3%), with or without previous sternotomy (PS and non-PS groups, respectively). Propensity matching resulted in 44 patient pairs. The primary end point was overall survival at 30 days, 1 year, 2, and 5 years, postoperatively. Secondary end points were adverse events. Results The overall cumulative survival rates for the two study groups were significantly different (77, 63, 54, and 38% for non-PS group vs 64, 39, 27, and 24% for PS group, p = 0.036). In the PS group, there was a higher need for intraoperative implantation of short-term right ventricular assist device (22.7 vs 6.8%, p = 0.034) and a higher incidence of hepatic dysfunction (20.5 vs 4.5%, p = 0.025) and acute kidney dysfunction (40.9 vs 20.5%, p = 0.032). Conclusion PS is a reliable predictor of mortality and morbidity after LVAD implantation.

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