Swansea, United Kingdom
Swansea, United Kingdom

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Chan C.H.H.,University of Swansea | Chan C.H.H.,Calon Cardio Technology Ltd | Hilton A.,Calon Cardio Technology Ltd | Foster G.,Calon Cardio Technology Ltd | Hawkins K.,University of Swansea
Artificial Organs | Year: 2012

The Harboe spectrophotometric assay is regarded as one of the safest and most reproducible methods for measuring plasma free hemoglobin (pfHb). However, there is still some ambiguity in the application of the assay when assessing the hemolytic performance of ventricular assist devices (VADs). The purpose of this study was to reexamine and compare values of pfHb obtained using different concentrations of plasma diluent (Na2CO3) as cited by various studies such that a standard practice may be recommended for the application of the Harboe assay in the hemolytic evaluation of VADs, allowing reliable comparisons to be made between laboratories. As a means to examine the Harboe assay, a BioMedicus BPX-80 was tested using both whole blood and a washed suspension of red blood cells (RBCs). Results show that for whole blood, the pfHb may be underestimated by 13-23%, dependent upon the concentration of Na2CO3 diluent solution. This trend was not observed for the washed suspension of RBCs. Furthermore, it is shown that the concentration of diluent influences the stability of a sample. The results of this study show that the problems associated with the incongruity of pfHb readings are a direct result of the precipitation of proteins from the plasma under alkaline conditions; as the molarity of the diluent controls pH, it becomes essential to use the appropriate concentration of Na2CO3 diluent in order to avoid turbidity of the solution and the consequent misrepresentation of pfHb values. Such standardization is pertinent when measuring the very low levels of pfHb observed during the in vivo testing of modern ventricular assist devices. © 2012, the Authors. Artificial Organs © 2012, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.


Leslie L.J.,Aston University | Marshall L.J.,Aston University | Devitt A.,Aston University | Hilton A.,Calon Cardio Technology Ltd | Tansley G.D.,Griffith University
Artificial Organs | Year: 2013

Cell exclusion is the phenomenon whereby the hematocrit and viscosity of blood decrease in areas of high stress. While this is well known in naturally occurring Poiseuille flow in the human body, it has never previously been shown in Couette flow, which occurs in implantable devices including blood pumps. The high-shear stresses that occur in the gap between the boundaries in Couette flow are known to cause hemolysis in erythrocytes. We propose to mitigate this damage by initiating cell exclusion through the use of a spiral-groove bearing (SGB) that will provide escape routes by which the cells may separate themselves from the plasma and the high stresses in the gap. The force between two bearings (one being the SGB) in Couette flow was measured. Stained erythrocytes, along with silver spheres of similar diameter to erythrocytes, were visualized across a transparent SGB at various gap heights. A reduction in the force across the bearing for human blood, compared with fluids of comparable viscosity, was found. This indicates a reduction in the viscosity of the fluid across the bearing due to a lowered hematocrit because of cell exclusion. The corresponding images clearly show both cells and spheres being excluded from the gap by entering the grooves. This is the first time the phenomenon of cell exclusion has been shown in Couette flow. It not only furthers our understanding of how blood responds to different flows but could also lead to improvements in the future design of medical devices. © 2013, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.


Trademark
Calon Cardio Technology Ltd | Date: 2012-06-05

Surgical and medical apparatus and instruments for use in cardiac surgery and parts and fittings sold therewith; cardiac implant devices and heart pumps made of artificial materials and parts and fittings sold therewith; cannulae; catheters.


Trademark
Calon Cardio Technology Ltd | Date: 2012-06-05

Surgical and medical apparatus and instruments for use in cardiac surgery and parts and fittings sold therewith; cardiac implant devices and heart pumps made of artificial materials and parts and fittings sold therewith; cannulae; catheters.


Grant
Agency: GTR | Branch: Innovate UK | Program: | Phase: Collaborative Research & Development | Award Amount: 1.67M | Year: 2013

Advanced heart failure is a large and growing healthcare challenge not adequately met by traditional medical management, cardiac resynchronisation or transplantation. Ventricular assist devices (VADs) can address this need and have shown very promising clinical results. However, existing VADs are expensive, have high utilisation costs due to significant complications and require extensive invasive surgery for implantation. Calon’s MiniVAD addresses these problems with a smaller pump, reduced blood damage and significantly improved health economics. This project proposes the development of novel blood damage assays and the subsequent detailed in-vitro and in-vivo evaluation of the MiniVAD to provide the performance and safety data necessary to support a regulatory application to begin human clinical studies


Patent
Calon Cardio Technology Ltd | Date: 2010-04-19

The pump is of an axial flow rotary pump, suitable for implantation into the human heart or vascular system, and comprises an elongate tubular casing (1,2) defining an inlet (4) for blood, an outlet (5) for blood longitudinally spaced from the inlet, and a primary substantially axial blood flow path (6) along the interior of the casing from the inlet to the outlet, the casing including an electric motor stator (7). There is an elongate rotatable element (3) arranged to fit within the casing with spacing between an outer surface of the rotatable element and an inner surface of the casing. The tubular rotatable element comprises an electric motor rotor portion (10) arranged to be driven by the electric motor stator and a rotary impeller (11) for impelling blood along the blood flow path. The casing is formed as an upstream tubular member (2) having an open front end, and a downstream tubular member (1) having open front and rear ends, the upstream tubular member including the stator, and the downstream tubular member, which encircles the impeller, having a rear end fitted to the upstream tubular member in fluid tight manner.


Patent
Calon Cardio Technology Ltd | Date: 2013-10-17

The pump, which is for implantation into a human heart, has a flow path through a housing (1), a rotatable pump member (21) within the housing for causing fluid to flow along the flow path, the pump member being rotatably coupled to the housing about an upstream bearing (32) and a downstream bearing (33). The downstream bearing comprises a bearing member (34) on the pump member and a complementary bearing formation (35) on the housing, The pump has a mechanical adjuster (42) for fine adjustment of the position of the bearing formation (35) along an axis (A) of the pump member; the mecahnical adjuster being preferably one or more screws (42) for adjustable movement of a boss (40) along the axis (A), the adjustable movement being permitted by flexure of a plate member (41) integral with the boss.


Patent
Calon Cardio Technology Ltd | Date: 2012-07-18

The cardiac pump, which is suitable for implantation into a ventricle of a human heart, has a primary blood flow path through a housing, a rotatable pump member disposed within the housing for causing blood to flow along the primary flow path, the pump member being rotatably coupled to the housing about an upstream bearing and a downstream bearing. The pump member includes an impeller shroud defining a secondary flow path in fluid communication with the primary flow path. The downstream bearing comprises a rotational bearing member and a stationary bearing seat for the bearing member, there being a circumferential transition between the bearing seat and the bearing member, the circumferential transition being disposed in the secondary flow path and arranged to be washed by blood passing along the secondary flow path.


Patent
Calon Cardio Technology Ltd. | Date: 2014-05-21

A plain bearing assembly for a cardiac pump, the plain bearing assembly comprising; a rotational portion which, in use, rotates with a cardiac pump rotor, the rotational portion configured to engage a stationary portion of a cardiac pump housing, the stationary portion comprising one or more first bearing surfaces and the rotational portion comprising one or more second bearing surfaces, the one or more second bearing surfaces configured so as to be in contact with the one or more first bearing surfaces, therein defining a bearing interface between the one or more first bearing surfaces and the one or more second bearing surfaces during rotation of the rotational portion, wherein the rotational portion comprises one or more first flow channels configured to interrupt the bearing interface and permit blood to flow between an outside of the plain bearing assembly and a center of the plain bearing assembly.


PubMed | Calon Cardio Technology Ltd
Type: | Journal: Artificial organs | Year: 2016

Small affordable automated hematology analyzers that produce rapid and accurate complete blood cell counts are a valuable tool to researchers developing blood-handling medical devices, such as ventricular assist devices, for in vitro safety assessments. In such studies, it is common to use the blood of large animals such as cattle and sheep. However, the commercially available instruments have not been evaluated for their ability to measure the blood counts of these animals. In this study, we compare, for the first time, four veterinary analyzers for blood counts on bovine and ovine blood samples. We look at ease of use, repeatability and agreement with a view to inform researchers of the benefits of these instruments in routine measurement of ovine and bovine bloods during in vitro testing. Complete blood cell counts and a three-part differential (granulocytes, monocytes, and lymphocytes) were measured by each of the instruments, and the results compared to those obtained from two additional analyzers used in a reference laboratory. Repeatability and agreement were evaluated using the Bland-Altman method; bias and 95% limits of agreement between the instruments, and between the instruments and two reference instruments, were used to evaluate instrument performance. In summary, there are advantages and disadvantages with all instruments. Of the four instruments tested, the repeatability and agreement was fairly similar for all instruments except one instrument which cannot be recommended for bovine or ovine blood counts.

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