scholarly journals Optimization of Implantable Axial Pump to Increase Efficiency of Mechanical Circulatory Support

2017 ◽  
Vol 19 (2) ◽  
pp. 61-68
Author(s):  
S. V. Gautier ◽  
A. P. Kuleshov ◽  
A. E. Efimov ◽  
I. I. Agapov ◽  
G. P. Itkin
Keyword(s):  
Shear Stress ◽  
Mechanical Circulatory Support ◽  
Operation Mode ◽  
Flow Region ◽  
Point Of View ◽  
Circulatory Support ◽  
Hydraulic Efficiency ◽  
Pump Operation ◽  
Axial Pump ◽  
Increase Efficiency

Aim. To optimize implantable axial pump to increase hydraulic efficiency and reduce blood hemolysis. Materials and methods. In this article the basic geometric parameters of impeller’s geometry (the blade’s angle, the blade’s length and the twist angle’s ratio) were investigated and optimized using methods of computer hydrodynamics. The calculations were carried out for the optimum operation of the pump at the speed of 8000 rpm. Results. The main parameters of impeller’s geometric were determined which made it possible to increase efficiency of the pump by an average of 7.5% (depending on the pump operation mode) and pressure drop of 8% on average. The value of shear stress in the flow region obtained as a result of the calculations did not exceed 147 Pa admissible from the point of view of blood hemolysis.

scholarly journals 5065Platelet desialylation induced by high shear-stress mechanical circulatory support

2018 ◽  
Vol 39 (suppl_1) ◽  
Author(s):  
H Spillemaeker ◽  
A Dupont ◽  
A Kauskot ◽  
A Rauch ◽  
F Vincent ◽  
...  
Keyword(s):  
Shear Stress ◽  
Mechanical Circulatory Support ◽  
Circulatory Support ◽  
High Shear ◽  
High Shear Stress

scholarly journals Mechanical shear stress and leukocyte phenotype and function: Implications for ventricular assist device development and use

2018 ◽  
Vol 42 (3) ◽  
pp. 133-142 ◽  
Author(s):  
Gemma Radley ◽  
Sabrina Ali ◽  
Ina Laura Pieper ◽  
Catherine A Thornton
Keyword(s):  
Heart Failure ◽  
Shear Stress ◽  
Mechanical Circulatory Support ◽  
Circulatory Support ◽  
Modern World ◽  
Mechanical Trauma ◽  
Ventricular Assist ◽  
End Stage ◽  
And Function ◽  
The Impact

Heart failure remains a disease of ever increasing prevalence in the modern world. Patients with end-stage heart failure are being referred increasingly for mechanical circulatory support. Mechanical circulatory support can assist patients who are ineligible for transplant and stabilise eligible patients prior to transplantation. It is also used during cardiopulmonary bypass surgery to maintain circulation while operating on the heart. While mechanical circulatory support can stabilise heart failure and improve quality of life, complications such as infection and thrombosis remain a common risk. Leukocytes can contribute to both of these complications. Contact with foreign surfaces and the introduction of artificial mechanical shear stress can lead to the activation of leukocytes, reduced functionality and the release of pro-inflammatory and pro-thrombogenic microparticles. Assessing the impact of mechanical trauma to leukocytes is largely overlooked in comparison to red blood cells and platelets. This review provides an overview of the available literature on the effects of mechanical circulatory support systems on leukocyte phenotype and function. One purpose of this review is to emphasise the importance of studying mechanical trauma to leukocytes to better understand the occurrence of adverse events during mechanical circulatory support.

scholarly journals Haemolysis induced by mechanical circulatory support devices: unsolved problems

Perfusion ◽  
2020 ◽  
Vol 35 (6) ◽  
pp. 474-483
Author(s):  
Inge Köhne
Keyword(s):  
Shear Stress ◽  
Continuous Flow ◽  
Mechanical Circulatory Support ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Ventricular Assist ◽  
Theoretical Approaches ◽  
Blood Pumps ◽  
Mechanical Circulatory Support Devices ◽  
Support Devices

Since the use of continuous flow blood pumps as ventricular assist devices is standard, the problems with haemolysis have increased. It is mainly induced by shear stress affecting the erythrocyte membrane. There are many investigations about haemolysis in laminar and turbulent blood flow. The results defined as threshold levels for the damage of erythrocytes depend on the exposure time of the shear stress, but they are very different, depending on the used experimental methods or the calculation strategy. Here, the results are resumed and shown in curves. Different models for the calculation of the strengths of erythrocytes are discussed. There are few results reported about tests of haemolysis in blood pumps, but some theoretical approaches for the design of continuous flow blood pumps according to low haemolysis have been investigated within the last years.

scholarly journals Optimization of Axial Pump Characteristic Dimensions and Induced Hemolysis for Mechanical Circulatory Support Devices

ASAIO Journal ◽  
2018 ◽  
Vol 64 (6) ◽  
pp. 727-734 ◽  
Author(s):  
Theodosios Korakianitis ◽  
Mohammad Amin Rezaienia ◽  
Gordon Paul ◽  
Eldad Avital ◽  
Martin Rothman ◽  
...  
Keyword(s):  
Mechanical Circulatory Support ◽  
Circulatory Support ◽  
Axial Pump ◽  
Mechanical Circulatory Support Devices ◽  
Support Devices

scholarly journals Mechanical circulatory support in patients with cardiogenic shock not secondary to cardiotomy: a network meta-analysis

2021 ◽  
Author(s):  
Stefano Benenati ◽  
Matteo Toma ◽  
Claudia Canale ◽  
Rocco Vergallo ◽  
Roberta Della Bona ◽  
...  
Keyword(s):  
Mechanical Circulatory Support ◽  
Meta Analysis ◽  
Circulatory Support ◽  
Short Term ◽  
Randomized Controlled ◽  
Axial Pump ◽  
Short Term Mortality ◽  
Secondary Endpoints ◽  
Important Quality ◽  
Significant Publication Bias

Abstract To compare the efficacy and safety of different mechanical circulatory support (MCS) devices in CS. A total of 24 studies (7 randomized controlled trials—RCTs—and 17 non-RCTs) involving 11,117 patients were entered in a Bayesian network meta-analysis. The primary endpoint was 30-day mortality. Secondary endpoints were stroke and bleeding (requiring transfusion and/or intracranial and/or fatal). Compared with no MCS, extra-corporeal membrane oxygenation (ECMO) reduced 30-day mortality when used both alone (OR 0.37, 95% CrI 0.15–0.90) and together with the micro-axial pump Impella (OR 0.13, 95% CrI 0.02–0.80) or intra-aortic balloon pump (IABP) (OR 0.19, 95% CrI 0.05–0.63), although the relevant articles were affected by significant publication bias. Consistent results were obtained in a sensitivity analysis including only studies of CS due to myocardial infarction. After halving the weight of studies with a non-RCT design, only the benefit of ECMO + IABP on 30-day mortality was maintained (OR 0.22, 95% CI 0.057–0.76). The risk of bleeding was increased by TandemHeart (OR 13, 95% CrI 3.50–59), Impella (OR 5, 95% CrI 1.60–18), and IABP (OR 2.2, 95% CrI 1.10–4.4). No significant differences were found across MCS strategies regarding stroke. Although limited by important quality issues, the studies performed so far indicate that ECMO, especially if combined with Impella or IABP, reduces short-term mortality in CS. MCS increases the hazard of bleeding.

Design, Modeling, and Experimental Characterization of A Valveless Pulsatile Flow Mechanical Circulatory Support Device

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Mengtang Li ◽  
Ye Chen ◽  
Marvin J. Slepian ◽  
Joseph Howard ◽  
Seth Thomas ◽  
...  
Keyword(s):  
Shear Stress ◽  
Flow Rate ◽  
Pulsatile Flow ◽  
Mechanical Circulatory Support ◽  
Blood Flow Rate ◽  
Experimental Tests ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Bleeding Events ◽  
Prosthetic Valves

Abstract Mechanical circulatory support (MCS) devices, i.e., ventricular assist devices (VADs) and total artificial hearts (TAHs), while effective and vital in restoring hemodynamics in patients with circulatory compromise in advanced heart failure, remain limited by significant adverse thrombotic, embolic and bleeding events. Many of these complications relate to chronic exposure, via these devices, to nonpulsatile flow and the high shear stress created by current methods of blood propulsion or use of prosthetic valves. Here we propose a novel noncompressing single sliding vane MCS device to: 1) dramatically reduce pump operating speed thus potentially lowering the shear stress imparted to blood; 2) eliminate utilization of prosthetic valves thus diminishing potential shear stress generations; 3) allow direct flow rate control to generate physically desired blood flow rate include pulsatile flow; and 4) achieve compactness to fit into the majority of patients. The fundamental working principle and governing design equations are introduced first with multiple design and performance objectives presented. A first prototype was fabricated and experimental tests were conducted to validate the model with a 93.10% match between theoretical and experimental flow rate results. After model validation, the proposed MCS was tested to illustrate the ability of pulsatile flow generation. Finally, it was compared with some representative MCS pumps to discuss its potential of improving current MCS design. The presented work offers a novel MCS design and paves the way for next steps in device hemocompatibility testing.

scholarly journals Platelet Dysfunction During Mechanical Circulatory Support

2021 ◽  
Author(s):  
Yana Roka-Moiia ◽  
Samuel Miller-Gutierrez ◽  
Daniel E. Palomares ◽  
Joseph E. Italiano ◽  
Jawaad Sheriff ◽  
...  
Keyword(s):  
Shear Stress ◽  
Mechanical Circulatory Support ◽  
Platelet Adhesion ◽  
Surface Expression ◽  
Progressive Increase ◽  
Circulatory Support ◽  
Adhesion Receptors ◽  
Pulsatile Shear Stress ◽  
Functional Responsiveness

Objective: Mechanical circulatory support has emerged as lifesaving therapy for patients with advanced heart failure. However, mechanical circulatory support remains limited by a paradoxical coagulopathy accompanied by both thrombosis and bleeding. While mechanisms of mechanical circulatory support thrombosis are increasingly defined, mechanical circulatory support-related bleeding, as related to shear-mediated alteration of platelet function, remains poorly understood. We tested the hypothesis that platelet exposure to elevated shear stress, while a defined prothrombotic activator of platelets, coordinately induces downregulation of key platelet adhesion receptors GPIb (glycocalicin)-IX-V, α IIb β 3 , and P-selectin, thus decreasing platelet functional responsiveness to physiological stimuli. Approach and Results: Human gel-filtered platelets were exposed to continuous or pulsatile shear stress in vitro. Surface expression of platelet receptors and platelet-derived microparticle generation were quantified by flow cytometry. Shedding of receptor soluble forms were assessed via ELISA, and platelet aggregation was measured by optical aggregometry. We demonstrate that platelet exposure to elevated shear stress led to a downregulation of GPIb and α IIb β 3 receptors on platelets with a progressive increase in the generation of platelet-derived microparticles expressing elevated levels of α IIb β 3 and GPIb on their surface. No shear-mediated shedding of GPIb and β 3 subunit soluble fragments was detected. Soluble P-selectin was extensively shed from platelets, while surface expression of P-selectin on platelets and microparticles was not significantly altered by shear. Shear-mediated downregulation of GPIb, α IIb β 3 , and P-selectin on platelets was associated with an evident decrease of platelet aggregatory response induced by ADP and TRAP 6 (thrombin receptor activating peptide 6). Conclusions: Our data clearly indicate that accumulation of shear stress, consistent with supraphysiologic conditions characterizing device-supported circulation (1) induces adequate platelet degranulation, yet (2) causes downregulation of primary platelet adhesion receptors via ejection of receptor-enriched platelet-derived microparticles, thus mechanistically limiting platelet activation and the aggregatory response.

scholarly journals First experience in implantation of a mechanical circulatory support device based on a disk-type pump: an acute experiment

2020 ◽  
Vol 22 (2) ◽  
pp. 113-116
Author(s):  
M. O. Zhulkov ◽  
A. M. Golovin ◽  
E. O. Golovina ◽  
A. S. Grenaderov ◽  
A. V. Fomichev ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Blood Circulation ◽  
Venous Pressure ◽  
Operation Mode ◽  
Viscous Friction ◽  
Acute Experiment ◽  
Circulatory Support ◽  
Large Mammal ◽  
Pump Operation ◽  
Blood Clots

Objective: to carry out the implantation of an artificial left ventricle of the heart based on a disk-type pump in an acute experiment on a large mammal (mini-pig). Materials and methods. To test the surgical technique of implantation and assess the biocompatibility of the apparatus for mechanical support of blood circulation based on a viscous friction pump, an acute experiment was conducted on an animal. A large mammal (mini-pig weighing 90 kg) was used as an experimental model. The implantation of the pump was performed extracorporeally according to the scheme «the apex of the left ventricle – the descending thoracic aorta». During the experiment, invasive blood pressure, central venous pressure, cardiac arrhythmias, body temperature, blood gas composition, activated coagulation time were monitored. Under the control of transesophageal echocardiography, the pump operation mode was set with parameters – speed 2400–2600, productivity 4 ± 0.5 l/min, average IAD – 70–80 mm Hg. Results. In the course of the experiment, the fundamental possibility of using the developed disk-type pump as a device for supporting blood circulation was proved. For 4 hours, the pump provided adequate hemodynamic parameters with an average productivity of 4 ± 0.5 l/min and 2500 rpm. After 4 hours of operation of the pump in the conditions of inactivated heparin (AST – 114 sec), no blood clots were found between the pump disks. Conclusion The hemodynamics feature of the disk pump allows you to develop sufficient performance parameters to ensure adequate blood circulation. The mechanism of action of the «boundary layer» minimizes the risk of blood clots in the pump cavity. However, the topographic and anatomical features of the pig’s body do not allow experiments with a long observation period.

Long-term survival on mechanical circulatory support

2008 ◽  
Vol 7 ◽  
pp. 173-173
Author(s):  
A GKOUZIOUTA ◽  
E LEONTIADIS ◽  
S ADAMOPOULOS ◽  
A MANGINAS ◽  
G KARAVOLIAS ◽  
...  
Keyword(s):  
Mechanical Circulatory Support ◽  
Circulatory Support ◽  
Term Survival ◽  
Long Term Survival
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