Platelet Activity State in Human, Bovine, and Ovine Species Under Constant Shear Stress: A Comparative Study

2013 ◽  
Author(s):  
Phat L. Tran ◽  
Valerie M. Merkle ◽  
Tracy DeCook ◽  
Marcus Hutchinson ◽  
Jawaad Sheriff ◽  
...  
Keyword(s):  
Shear Stress ◽  
Blood Compatibility ◽  
Platelet Reactivity ◽  
Total Artificial Heart ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Large Animal ◽  
Platelet Activity ◽  
Bridge To Transplant ◽  
Large Animal Models

Mechanical circulatory support (MCS) devices, such as the total artificial heart and ventricular assist devices, are employed as bridge-to-transplant or destination therapies for advanced heart failure.[1] Recipients of these life-saving MCS devices have to endure life-long antiplatelet regimens to counteract thromboembolic events resulting from exposure of platelets to high shear stress. Often, large animal models, i.e. bovine and ovine, have been utilized to evaluate the performance and blood compatibility of these cardiovascular devices. Therefore, understanding and correlating the interspecies differences of platelet reactivity is crucial in optimizing the design of MCS devices.

Dynamic Shear Stress Induced Platelet Activation in Blood Recirculation Devices: Implications for Thrombogenicity Minimization

2009 ◽  
Author(s):  
Gaurav Girdhar ◽  
Jawaad Sheriff ◽  
Michalis Xenos ◽  
Yared Alemu ◽  
Thomas Claiborne ◽  
...  
Keyword(s):  
Shear Stress ◽  
Platelet Activation ◽  
Heart Valves ◽  
Total Artificial Heart ◽  
Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Bridge To Transplant ◽  
End Stage ◽  
Effective Design

Implantable blood recirculation devices such as ventricular assist devices (VADs) and more recently the temporary total artificial heart (TAH-t) are promising bridge-to-transplant (BTT) solutions for patients with end-stage cardiovascular disease. However, blood flow in and around certain non-physiological geometries, mostly associated with pathological flow around mechanical heart valves (MHVs) of these devices, enhances shear stress-induced platelet activation, thereby significantly promoting flow induced thrombogenicity and subsequent complications such as stroke, despite a regimen of post-implant antithrombotic agents. Careful characterization of such localized high shear stress trajectories in these devices by numerical techniques and corresponding experimental measurements of their accentuated effects on platelet activation and sensitization, is therefore critical for effective design optimization of these devices (reducing the occurrence of pathological flow patterns formation) for minimizing thrombogenicity [1].

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 Driveline Infection in Ventricular Assist Devices and Its Implication in the Present Era of Destination Therapy

2017 ◽  
Vol 9 ◽  
pp. 117906521771421 ◽  
Author(s):  
Gabriel A Hernandez ◽  
Jonatan D Nunez Breton ◽  
Sandra V Chaparro
Keyword(s):  
Treatment Options ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Destination Therapy ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Bridge To Transplant ◽  
Innovative Therapy

Advances in mechanical circulatory support devices provided the technology to develop long-term, implantable left ventricular assist devices as bridge to transplant, destination therapy, and in a lesser group of patients, as bridge to recovery. Despite the benefits from this innovative therapy, with their increased use, many complications have been encountered, one of the most common being infections. With the driveline acting as a portal to the exterior environment, an infection involving this structure is the most frequent one. Because patients with destination therapy are expected to receive circulatory support for a longer period of time, we will focus this review on the risk factors, prevention, and treatment options for driveline infections.

Design Optimization of Rotary Blood Pumps: Alternatives to Anticoagulation Therapy

2011 ◽  
Author(s):  
Gaurav Girdhar ◽  
Michalis Xenos ◽  
Wei-Che Chiu ◽  
Yared Alemu ◽  
Bryan Lynch ◽  
...  
Keyword(s):  
Heart Valves ◽  
Anticoagulation Therapy ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Shear Stresses ◽  
Ventricular Assist ◽  
Bridge To Transplant ◽  
Life Saving ◽  
Optimization Methodology ◽  
Rotary Blood Pumps

Mechanical circulatory support (MCS) devices such as the ventricular assist devices (VADs) provide life saving short-term bridge-to-transplant solutions (1) to a large proportion of patients who suffer from chronic heart failure. Although hemodynamically efficient, such devices are burdened with high incidence of thromboembolic events due to non-physiological flow past constricted geometries where platelets (the principal cellular clotting elements in blood) are exposed to elevated shear stresses and exposure times (2) — requiring mandatory anticoagulation. We recently developed an optimization methodology — Device Thrombogenicity Emulator (DTE)(3) — that integrates device specific hemodynamic stresses (from numerical simulations) with experimental measurements of platelet activation. The DTE was successfully applied by our group to measure / optimize the thromboresistance of mechanical heart valves (MHV) (3, 4).

scholarly journals Success of Thrombectomy in Management of Ischemic Stroke in Two Patients with SynCardia Total Artificial Heart in Bridge-to-Transplantation

2021 ◽  
Vol 8 (9) ◽  
pp. 126
Author(s):  
Brendan Le Picault ◽  
Charles-Henri David ◽  
Pierre-Louis Alexandre ◽  
Cédric Lenoble ◽  
Philippe Bizouarn ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Case Report ◽  
Artificial Heart ◽  
Mechanical Thrombectomy ◽  
Total Artificial Heart ◽  
Neurological Deficits ◽  
Circulatory Support ◽  
Hemorrhagic Complication ◽  
Bridge To Transplant ◽  
End Stage

Introduction: Circulatory assistance from a SynCardia Total Artificial Heart (SynCardia-TAH) is a reliable bridge-to-transplant solution for patients with end-stage biventricular heart failure. Ischemic strokes affect about 10% of patients with a SynCardia-TAH. We report for the first time in the literature two successful thrombectomies to treat the acute phase of ischemic stroke in two patients treated with a SynCardia-TAH in the bridge-to-transplant (BTT). Case report: We follow two patients with circulatory support from a SynCardia-TAH in the bridge-to-transplant for terminal biventricular cardiac failure with ischemic stroke during the support period. An early in-hospital diagnosis enables the completion of a mechanical thrombectomy within the first 6 h of the onset of symptoms. There was no intracranial hemorrhagic complication during or after the procedure and the patients fully recovered from neurological deficits, allowing a successful heart transplant. Conclusion: This case report describes the possibility of treating ischemic strokes under a SynCardia-TAH by mechanical thrombectomy following the same recommendations as for the general population with excellent results and without any hemorrhagic complication during or after the procedure.

In-Vitro Thrombogenicity Assessment of Mechanical Circulatory Support Devices and Prosthetic Heart Valves

2010 ◽  
Author(s):  
Thomas E. Claiborne ◽  
Gaurav Girdhar ◽  
Jawaad Sheriff ◽  
Jolyon Jesty ◽  
Marvin J. Slepian ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Mechanical Circulatory Support ◽  
Heart Valves ◽  
Anticoagulation Therapy ◽  
Ventricular Assist Devices ◽  
Patient Specific ◽  
Circulatory Support ◽  
Prosthetic Heart Valves ◽  
Bridge To Transplant ◽  
Uncontrolled Bleeding

Mechanical circulatory support (MCS) devices developed for end-stage heart failure or as a bridge-to-transplant include total artificial hearts (TAH) and ventricular assist devices (VAD) and utilize prosthetic heart valves (PHV) or rotary impellers to control blood recirculation [1]. These devices are currently not optimized to reduce the incidence of pathological flow patterns that cause elevated stresses leading to platelet activation and thrombosis. Although the latter is partially mitigated by lifelong anticoagulation therapy, it dramatically increases the risk of uncontrolled bleeding. For instance thromboembolic stroke-related complications (∼2%) were relatively less with the TAH-t compared to uncontrolled bleeding due to anticoagulation use (∼20%) [2]. Platelet activation should therefore be quantified and optimized based on patient-specific cardiac outputs in device prototypes before clinical use.

Percutaneous Endoscopic Gastrostomy Tube in a Syncardia™ Total Artificial Heart

2016 ◽  
Vol 19 (1) ◽  
pp. 014
Author(s):  
Amit Prasad ◽  
Kai Singbartl ◽  
Jacqueline Boone ◽  
Behzad Soleimani ◽  
Mohamad Zeriouh ◽  
...  
Keyword(s):  
Percutaneous Endoscopic Gastrostomy ◽  
Nutritional Support ◽  
Artificial Heart ◽  
Left Ventricular ◽  
Total Artificial Heart ◽  
Ventricular Assist Devices ◽  
Percutaneous Endoscopic Gastrostomy Tube ◽  
Left Ventricular Assist Devices ◽  
Bridge To Transplant ◽  
Endoscopic Gastrostomy

As a bridge to transplant, the Syncardia™ total artificial heart (TAH) is an option for patients who are not candidates for left ventricular assist devices (LVAD) due to right ventricular failure. The need for nutritional support in these patients is essential for a favorable outcome. Low body mass indexes and albumin levels have been associated with increased morbidity and mortality in cardiac surgery patients [Alverdy 2003]. It is not uncommon for postoperative patients to have difficulty in consuming enough calories after surgery, which is further complicated by a hypermetabolic demand due to surgical stress. Enteral nutrition has typically been favored for gut mucosal integrity and bacterial flora [Alverdy 2003] [Engleman 1999]. We describe the need for prolonged enteral nutritional support in a TAH patient that was accomplished with a percutaneous endoscopic gastrostomy (PEG) tube.

scholarly journals Bovine Model of Doxorubicin-Induced Cardiomyopathy

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Carlo R. Bartoli ◽  
Kenneth R. Brittian ◽  
Guruprasad A. Giridharan ◽  
Steven C. Koenig ◽  
Tariq Hamid ◽  
...  
Keyword(s):  
Interstitial Fibrosis ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Plasma Norepinephrine ◽  
Large Animal ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Large Animal Models ◽  
Lv Dysfunction ◽  
Sequential Administration

Left ventricular assist devices (LVADs) constitute a recent advance in heart failure (HF) therapeutics. As the rigorous experimental assessment of LVADs in HF requires large animal models, our objective was to develop a bovine model of cardiomyopathy. Male calves (n=8) were used. Four animals received 1.2 mg/kg intravenous doxorubicin weekly for seven weeks and four separate animals were studied as controls. Doxorubicin-treated animals were followed with weekly echocardiography. Target LV dysfunction was defined as an ejection fraction ≤35%. Sixty days after initiating doxorubicin, a terminal study was performed to determine hemodynamic, histological, biochemical, and molecular parameters. All four doxorubicin-treated animals exhibited significant (P<0.05) contractile dysfunction, with target LV dysfunction achieved in three animals. Doxorubicin-treated hearts exhibited significantly reduced coronary blood flow and interstitial fibrosis and significantly increased apoptosis and myocyte size. Gene expression of atrial natriuretic factor increased more than 3-fold. Plasma norepinephrine and epinephrine levels were significantly increased early and late during the development of cardiomyopathy, respectively. We conclude that sequential administration of intravenous doxorubicin in calves induces a cardiomyopathy with many phenotypic hallmarks of the failing human heart. This clinically-relevant model may be useful for testing pathophysiologic responses to LVADs in the context of HF.

Blood Interaction with a Bioline Heparin Coated HIA-VAD: A Study on Calves

1997 ◽  
Vol 20 (1) ◽  
pp. 43-50 ◽  
Author(s):  
K.W.H.J. Van Der Kamp ◽  
C.P.E. Magielse ◽  
J.M. Elstrodt ◽  
J. Van Der Meer ◽  
W. Van Oeveren ◽  
...  
Keyword(s):  
Blood Cell ◽  
Degradation Products ◽  
Blood Compatibility ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Mechanical Trauma ◽  
Control Group ◽  
Implantation Procedure

The blood compatibility of ventricular assist devices developed by the Helmholtz Institute Aachen (HA-VAD's) was tested on calves. Seven calves received a non-coated HIA-VAD (control) and three a Bioline heparin coated device. The circulatory support of these HIA-VAD's lasted one week. Mechanical blood cell trauma estimated by hematocrit (Hct), hemoglobin (total Hb) and free plasma hemoglobin (free Hb) levels did not differ in either group. All HIA-VAD's in the control group remained thrombus free, except on one occasion when an inflow cannula was obstructed by a thrombus located in the tip. After circulatory support, the animals in this group seemed clinically healthy. However, thrombus formation was observed in the three heparin coated HIA-VAD's. One animal in this group died from complications after re-operation for pneumothorax on the fifth day of support, whereas the other two animals seemed clinically healthy. In these three animals, a stronge decrease in platelet numbers was measured even after 24 hours of support which recovered after 72 hours. This decrease in platelet numbers was associated with a lower degree of platelet aggregation ability stimulated by ADP (p<0.05). Fibrin(ogen) degradation products (FDP) increased significantly immediately after the implantation procedure (p<0.05). Fibrinogen levels initially decreased during the implantation procedure, but increased thereafter in both groups. The FDP levels remained high in this group, although the FDP levels in both groups were decreased after the implantation procedure. The ex vivo measured circulating heparin levels were lower in the heparin coated HIV-VAD group despite the equally administrated heparin doses in both animal groups. No differences were measured in either group with regard to white blood cell (WBC) numbers and complement hemolytic activity (CH50). Despite these hemostatic changes, no mechanical trauma could be demonstrated after seven days of circulatory support.

scholarly journals Acquired von Willebrand Syndrome and Platelet Function Defects during Extracorporeal Life Support (Mechanical Circulatory Support)

2020 ◽  
Vol 40 (02) ◽  
pp. 221-225
Author(s):  
Axel Schlagenhauf ◽  
Johannes Kalbhenn ◽  
Ulrich Geisen ◽  
Friedhelm Beyersdorf ◽  
Barbara Zieger
Keyword(s):  
Shear Stress ◽  
Life Support ◽  
Bleeding Risk ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Recurrent Bleeding ◽  
Mechanical Destruction ◽  
Acquired Von Willebrand Syndrome ◽  
Increased Risk ◽  
Von Willebrand

AbstractPatients with ventricular assist devices (VADs) and extracorporeal membrane oxygenation (ECMO) suffer from an increased risk for thromboembolic events as well as for hemorrhages. High shear stress in the mechanical device results in acquired von Willebrand syndrome (AVWS), characterized by a loss of high-molecular-weight multimers of von Willebrand factor (VWF) leading to an increased bleeding risk. Onset of AVWS occurs within hours, persists during the whole period of mechanical support, and subsides rapidly after explantation. Patients with the older HeartMate II exhibit more severe AVWS than those with the newer HeartMate III, thanks to lower shear stress in the latter. All ECMO and VAD patients exhibit thrombocytopathia and often thrombocytopenia which further increases the bleeding risk. Etiological models for AVWS are increased cleavage by the metalloproteinase ADAMSTS13, mechanical destruction of VWF, and shear-induced VWF binding to platelets. Platelet secretion defects may be caused by transient platelet activation leading to degranulation. AVWS can be diagnosed by detection of VWF multimers using gel-electrophoresis and functional assays of varying sensitivity (VWF ristocetin cofactor activity, VWF activity, VWF collagen binding). Platelet dysfunction is monitored using light transmission aggregometry and secretion defects are detectable using flow cytometry. Modest use of anticoagulants and a target-controlled therapy based on VWF parameters and other coagulation and platelet parameters are shown to be beneficial in this patient group. Persistent hemorrhages may be controlled with tranexamic acid and platelet concentrates. Prompt weaning from the device, when indicated, is the best therapeutic option to prevent recurrent bleeding.

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