scholarly journals Evaluation of the efficiency of a new pulsatile flow‑generating circulatory-assist system in rotary blood pumps. Research on a mathematical model

2021 ◽  
Vol 23 (4) ◽  
pp. 73-78
Author(s):  
G. P. Itkin ◽  
A. I. Syrbu ◽  
A. P. Kyleshov ◽  
A. S. Buchnev ◽  
A. A. Drobyshev
Keyword(s):  
Mathematical Model ◽  
Pulsatile Flow ◽  
Circulatory System ◽  
Left Ventricular ◽  
Left Ventricular Cavity ◽  
Pump Speed ◽  
Diastolic Phase ◽  
Flow Generation ◽  
Blood Inflow ◽  
Rotary Blood Pumps

Objective: to study the effect of a pulsatile flow-generation (PFG) device on the basic hemodynamic parameters of the circulatory system using a mathematical model.Results. Modelling and simulation showed that the use of PFG significantly (76%) increases aortic pulse pressure. The proposed mathematical model adequately describes the dynamics of the circulatory system and metabolism (oxygen debt) on physical activity in normal conditions and heart failure, and the use of non-pulsatile and pulsatile circulatory-assist systems. The mathematical model also shows that the use of PFG device blocks the development of rarefaction in the left ventricular cavity associated with a mismatch of blood inflow and outflow in diastolic phase when there is need to increase systemic blood flow by increasing the rotary pump speed.

scholarly journals A Novel Control Method for Rotary Blood Pumps as Left Ventricular Assist Device Utilizing Aortic Valve State Detection

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Dmitry Petukhov ◽  
Leonie Korn ◽  
Marian Walter ◽  
Dmitry Telyshev
Keyword(s):  
Heart Rate ◽  
Aortic Valve ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Control Method ◽  
Left Ventricular ◽  
Pump Speed ◽  
Pump Flow ◽  
Blood Pumps ◽  
Rotary Blood Pumps

A novel control method for rotary blood pumps is proposed relying on two different objectives: regulation of pump flow in accordance with desired value and the maintenance of partial support with an open aortic valve by the variation of pump speed. The estimation of pump flow and detection of aortic valve state was performed with mathematical models describing the first- and second generation of Sputnik rotary blood pumps. The control method was validated using a cardiovascular system model. The state of the aortic valve was detected with a mean accuracy of 91% for Sputnik 1 and 96.2% for Sputnik 2 when contractility, heart rate, and systemic vascular resistance was changed. In silico results for both pumps showed that the proposed control method can achieve the desired pump flow level and maintain the open state of the aortic valve by periodically switching between two objectives under contractility, heart rate, and systemic vascular resistance changes. The proposed method showed its potential for safe operation without adverse events and for the improvement of chances for myocardial recovery.

Restoring pulsatility and peakVO2 in the era of continuous flow, fixed pump speed, left ventricular assist devices: ‘A hypothesis of pump's or patient's speed?’

2019 ◽  
Vol 26 (17) ◽  
pp. 1806-1815 ◽  
Author(s):  
Ioannis D Laoutaris
Keyword(s):  
Pulsatile Flow ◽  
Continuous Flow ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Peak Oxygen Consumption ◽  
Current Evidence ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Pump Speed ◽  
Left Ventricular Assist

Despite significant improvement in survival and functional capacity after continuous flow left ventricular assist device implantation, the patient's quality of life may remain limited by complications such as aortic valve insufficiency, thromboembolic episodes and gastrointestinal bleeding attributed to high shear stress continuous flow with attenuated or absence of pulsatile flow and by a reduced peak oxygen consumption (peakVO2) primarily associated with a fixed pump speed operation. Revision of current evidence suggests that high technology pump speed algorithms, a ‘hypothesis of decreasing pump's speed’ to promote pulsatile flow and a ‘hypothesis of increasing pump's speed’ to increase peakVO2, may only partially reverse these barriers. A ‘hypothesis of increasing patient's speed’ is introduced, suggesting that exercise training may further contribute to the patient's recovery, enhancing peakVO2 and pulsatile flow by improving skeletal muscle oxidative capacity and strength, peripheral vasodilatory and ventilatory responses, favour changes in preload/afterload and facilitate native flow, formulating the rationale for further studies in the field.

A dreadful sign of aortic dissection: Aortic intimo-intimal intussusception with prominent intimal flap prolapsing into the left ventricular apex

VASA ◽  
2009 ◽  
Vol 38 (2) ◽  
pp. 181-184 ◽  
Author(s):  
Ozer ◽  
Davutoglu ◽  
Burma ◽  
Sucu ◽  
Sarı
Keyword(s):  
Aortic Dissection ◽  
Clinical Presentation ◽  
Left Ventricular ◽  
Left Ventricular Cavity ◽  
Acute Type ◽  
Clinical Form ◽  
Intimal Flap ◽  
Acute Type A Dissection ◽  
Type A Dissection ◽  
Intimal Intussusception

Intimo-intimal intussusception is an unusual clinical form of aortic dissection resulting from circumferential detachment of the intima. Clinical presentation varies according to the level of detached intima in the aorta. We present a case of acute type A dissection with prominent prolapse of the circumferential detachment intimal flap into the left ventricular cavity extended to the apex.

scholarly journals Can mechanical circulatory support be an effective treatment for HFpEF patients?

2021 ◽  
Author(s):  
Einar Gude ◽  
Arnt E. Fiane
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Mechanical Circulatory Support ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Cavity ◽  
Circulatory Support ◽  
Left Ventricular Assist Devices ◽  
Mechanical Pressure ◽  
Entry Points

AbstractHeart failure with preserved ejection fraction (HFpEF) is increasing in prevalence and represents approximately 50% of all heart failure (HF) patients. Patients with this complex clinical scenario, characterized by high filling pressures, and reduced cardiac output (CO) associated with progressive multi-organ involvement, have so far not experienced any significant improvement in quality of life or survival with traditional HF treatment. Left ventricular assist devices (LVAD) have offered a new treatment alternative in terminal heart failure patients with reduced ejection fraction (HFrEF), providing a unique combination of significant pressure and volume unloading together with an increase in CO. The small left ventricular cavity in HFpEF patients challenges left-sided pressure unloading, and new anatomical entry points need to be explored for mechanical pressure and volume unloading. Optimized and pressure/volume-adjusted mechanical circulatory support (MCS) devices for HFrEF patients may conceivably be customized for HFpEF anatomy and hemodynamics. We have developed a long-term MCS device for HFpEF patients with atrial unloading in a pulsed algorithm, leading to a significant reduction of filling pressure, maintenance of pulse pressure, and increase in CO demonstrated in animal testing. In this article, we will discuss HFpEF pathology, hemodynamics, and the principles behind our novel MCS device that may improve symptoms and prognosis in HFpEF patients. Data from mock-loop hemolysis studies, acute, and chronic animal studies will be presented.

Replication of left ventricular haemodynamics with a simple planar mitral valve model

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Anna Daub ◽  
Jochen Kriegseis ◽  
Bettina Frohnapfel
Keyword(s):  
Mitral Valve ◽  
Computational Models ◽  
Vortex Formation ◽  
Flow Characteristics ◽  
Left Ventricular ◽  
Computational Effort ◽  
Type Model ◽  
Diastolic Phase ◽  
Valve Model ◽  
Modelling Approach

AbstractTools for the numerical prediction of haemodynamics in multi-disciplinary integrated heart simulations have to be based on computational models that can be solved with low computational effort and still provide physiological flow characteristics. In this context the mitral valve model is important since it strongly influences the flow kinematics, especially during the diastolic phase. In contrast to a 3D valve, a vastly simplified valve model in form of a simple diode is known to be unable to reproduce the characteristic vortex formation and unable to promote a proper ventricular washout. In the present study, an adaptation of the widely used simplest modelling approach for the mitral valve is employed and compared to a physiologically inspired 3D valve within the same ventricular geometry. The adapted approach shows enhanced vortex formation and an improved ventricular washout in comparison to the diode type model. It further shows a high potential in reproducing the main flow characteristics and related particle residence times generated by a 3D valve.

scholarly journals Osteoprotegerin and RANKL-RANK-OPG-TRAIL signalling axis in heart failure and other cardiovascular diseases

2021 ◽  
Author(s):  
Mieczysław Dutka ◽  
Rafał Bobiński ◽  
Wojciech Wojakowski ◽  
Tomasz Francuz ◽  
Celina Pająk ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Cardiovascular Diseases ◽  
Vascular Endothelial Cells ◽  
Circulatory System ◽  
Prognostic Indicator ◽  
High Plasma ◽  
Mechanisms Of Action ◽  
Left Ventricular ◽  
High Ratio

AbstractOsteoprotegerin (OPG) is a glycoprotein involved in the regulation of bone remodelling. OPG regulates osteoclast activity by blocking the interaction between the receptor activator of nuclear factor kappa B (RANK) and its ligand (RANKL). More and more studies confirm the relationship between OPG and cardiovascular diseases. Numerous studies have confirmed that a high plasma concentration of OPG and a low concentration of tumour necrosis factor–related apoptosis inducing ligand (TRAIL) together with a high OPG/TRAIL ratio are predictors of poor prognosis in patients with myocardial infarction. A high plasma OPG concentration and a high ratio of OPG/TRAIL in the acute myocardial infarction are a prognostic indicator of adverse left ventricular remodelling and of the development of heart failure. Ever more data indicates the participation of OPG in the regulation of the function of vascular endothelial cells and the initiation of the atherosclerotic process in the arteries. Additionally, it has been shown that TRAIL has a protective effect on blood vessels and exerts an anti-atherosclerotic effect. The mechanisms of action of both OPG and TRAIL within the cells of the vascular wall are complex and remain largely unclear. However, these mechanisms of action as well as their interaction in the local vascular environment are of great interest to researchers. This article presents the current state of knowledge on the mechanisms of action of OPG and TRAIL in the circulatory system and their role in cardiovascular diseases. Understanding these mechanisms may allow their use as a therapeutic target in cardiovascular diseases in the future.

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