Abstract: A rotary blood pump may include one or more motor stators overlying exterior surfaces of a wall defining a pumping chamber. A rotatable impeller within the pumping chamber may have a hydrodynamic thrust bearing surface adapted to constrain a position of the impeller along an axis of rotation relative to the wall when the impeller is rotating about the axis of rotation. The impeller position may then be constrained without requiring a constant polarity magnetic force to be applied in the axial direction from a fixed position of the housing.

Abstract: Provided are a magnetic coupling as an axial bearing including a driven magnet (11B3) that is a permanent magnet provided to a rotating body (11) inside a casing (12) and a drive magnet (23A) that is a permanent magnet placed face to face with the driven magnet in a radial direction of the rotating body outside the casing to be magnetically coupled with the driven magnet, a driving motor (22) that rotatably drives the drive magnet about an axis (P) of the rotating body, a radial bearing that is a dynamic bearing having annular bearing surfaces (12B1, 11B1) centering on the axis on an inner wall of the casing and the rotating body, each of the annular bearing surfaces being arranged with a gap between the drive magnet and the driven magnet in the radial direction of the rotating body, and a closed impeller (11A) including a front shroud (11A1) arranged on a front side in the axis direction in the rotating body, a rear shroud (11A2) arranged on a rear side in the axis direction of the front shroud, and a vane (

Abstract: A blood pump controller includes a microcontroller and a communication interface. The microcontroller is configured to communicate with various types of blood pump communication modules. The microcontroller is further configured to determine, based on communication with a particular type of blood pump communication module, the particular type of blood pump communication module communicated with. The microcontroller is further configured to select, based on the determination of the particular type of blood pump communication module, control logic used to control the particular type of blood pump communication module. The microcontroller is further configured to generate, based on the selected control logic, commands for controlling the blood pump communication module. The communication interface is configured to connect the microcontroller to the particular type of blood pump communication module.

Abstract: A method and apparatus for long-term assisting the left ventricle of a heart to pump blood is disclosed which includes at least one transluminally deliverable pump and a transluminally deliverable support structure which secures the at least one pump within the aorta for long-term use.

Abstract: An intravascular miniature stent pump comprising an intravascular stent for implantation at an implant site within a blood vessel and a miniature pump mounted on the stent, wherein the pump allows an adequate blood flow to prevent clotting within a lumen of the stent, and wherein the blood flow is equal to or greater than a blood flow at the implant site before implantation.

Abstract: A demand responsive physiological control system for use with a rotary blood pump; said system including a pump controller which is capable of controlling pump speed of said pump; said system further including a physiological controller, and wherein said physiological controller is adapted to analyse input data relating to physiological condition of a user of said pump; and wherein said physiological controller determines appropriate pumping speed and sends a speed control signal to said pump controller to adjust pump speed; said system further including a physiological state detector which provides said input data indicative of at least one physiological state of said user, in use, to said physiological controller.

Abstract: A total artificial heart having a rotor with an impeller, wherein the rotor is mounted within a pump housing on a hollow shaft. The rotor is magnetically driven to produce rotary motion of the impeller for pumping blood. The motor is disposed within the pump housing such that axial translation within the housing acts as a shuttle valve to alternate flow between pulmonary and systemic circulation.

Abstract: A method of estimating the blood flow rate of a heart ventricle assist device which is positioned externally of, or implanted in, a patient. The assist device comprises a blood pump having a rapidly rotating, electrically powered impeller, and comprises briefly interrupting power to the impeller to cause its rotation to slow. From this, blood viscosity can be estimated, which viscosity is used to obtain real time, estimated blood flow rates and pressure heads. Apparatus for accomplishing this is disclosed.

Abstract: The invention relates to a hard magnetic object and a method for adjusting a magnetic vector of a hard magnetic object. Therefore, the invention has the object, to provide a hard magnetic object and a method for its manufacture, which hard magnetic object has, without being influenced by an outside magnetic circuit, a desired resultant magnetic vector, which is in the frame of a predetermined tolerance range, and furthermore, that the hard magnetic object has a higher maximal energy density compared to the State of Art.

Abstract: An artificial heart pump system has a heart pump implanted in a patient. A pump control unit worn by a patient includes a programmable device for adapting a secure aspect of heart pump operation in response to pump operating commands. The pump control unit has a wired interface and a wireless interface. A clinical external unit is adapted to be connected to the wired interface for delivering a pump operating command to the pump control unit. An auxiliary external unit is adapted to be connected to the wireless interface for collecting patient and/or pump system performance-related data from the pump control unit. The wireless interface is unable to consummate a pump operating command.

Abstract: A pump assembly and estimation and control system therefor, the pump adapted for continuous flow pumping of blood. In a particular form, the pump is a centrifugal pump wherein the impeller is entirely sealed within the pump housing and is exclusively hydrodynamically suspended therein against movement in three translational and two rotational degrees of freedom as the impeller rotates within the fluid urged by electromagnetic means external to the pump cavity. Hydrodynamic suspension is assisted by the impeller having deformities therein such as blades with surfaces tapered from the leading edges to the trailing edges of bottom and top surfaces thereof.

Abstract: A pump (10) includes a housing, a stator (20) supported in the housing, and a rotor assembly (30). The rotor assembly (30) includes a rotor (32) supported in the housing for rotation relative to the stator (20) about an axis (12). The rotor assembly (30) also includes a first impeller (34) operatively coupled to a first axial end of the rotor (32) for rotation with the rotor about the axis (12). The rotor assembly further includes a second impeller (36) operatively coupled to a second axial end of the rotor (32), opposite the first axial end, for rotation with the rotor about the axis (12). The rotor assembly (30) is movable along the axis (12) relative to the housing to adjust hydraulic performance characteristics of the pump (10).

Abstract: Disclosed is an intracardiac blood pump with a flexible screen between which discharge ports are located. The pump parts are connected to the flexible screen which catches the axially discharged flow and deflects the same in an axial direction. The delivery rate of the pump is increased by preventing impact losses and swirls at the discharge ports.

Abstract: Highly miniaturized electromechanical medical implants for certain applications cannot be fit into the available anatomic space unless their diameter can be made small enough. With devices such as rotary blood pumps or linear actuators, using rotary or linear electric motors, a thin motor stator that provides sufficient power must be encased in a corrosion resistant hermetically sealed enclosure into which electric wires must pass. Hermetic feedthroughs of the prior art are not structurally suited to maximal miniaturization with optimal electrical properties because of the need for welding of ferrules or other support components. The sub-miniature medical implants having the robust feedthrough of the present invention integrate the feedthrough wires, insulators, and sealing within a radially extending flange that is part of the end wall of the motor enclosure. This permits the largest feedthrough wire and thickest insulator to be built into the limited available space.

Abstract: A pump (10) includes a housing, a stator (20) supported in the housing, and a rotor assembly (30). The rotor assembly (30) includes a rotor (32) supported in the housing for rotation relative to the stator (20) about an axis (12). The rotor assembly (30) also includes a first impeller (34) operatively coupled to a first axial end of the rotor (32) for rotation with the rotor about the axis (12). The rotor assembly further includes a second impeller (36) operatively coupled to a second axial end of the rotor (32), opposite the first axial end, for rotation with the rotor about the axis (12). The rotor assembly (30) is movable along the axis (12) relative to the housing to adjust hydraulic performance characteristics of the pump (10).

Abstract: A system and method for controlling extracorporeal blood flow in a patient. The system includes a blood pump having a rotor, a plurality of rollers carried by the rotor and a pump chamber extended in tension about the rollers. A sensor measures an operating parameter of the blood pump and a controller, coupled to the sensor, calculates the flow efficiency of the blood pump based on the measured operating parameter. The controller is further configured to display the flow efficiency on the display device, and the operation of the blood pump is adjusted based on the flow efficiency when necessary.

Abstract: A rotary pump including an impeller rotatable within a housing. A load is imposed on the impeller as it rotates, in a direction that is substantially parallel to the axis of rotation and wherein the load stabilises the motion of the impeller. The load may be achieved by magnetically biasing the impeller.

Abstract: An impeller 22 includes a rotating shaft 7 supported rotatably by an upper bearing 9 and a lower bearing 20 at upper and lower ends, a plurality of vanes 6, an arm 18 coupling an inner circumferential side of the vanes to the rotating shaft, an annular coupling portion 8 coupled to an outer circumferential side of each vane, and a driven magnet portion 12 placed in a lower portion of the annular coupling portion. A drive magnet portion 16 provided at a rotor 13 and a driven magnet portion 12 are opposed to each other with a bottom wall of the housing interposed therebetween, and rotation of the rotor is transmitted to the impeller through magnetic coupling. A blockade member 23 is placed below the vanes and blocks a space in a region spreading between the rotating shaft and the annular coupling portion while leaving an opening 14 at least around the rotating shaft.

Abstract: By inserting a protruding portion 8b, which is installed to a center position of a rear end surface 8x of a fixed body 8, into a hole 4a, which is provided to a center position of an end surface 4x on a side of a fixed body 8 of a fixed shaft 4 that is connected to a fixed body 3, the fixed bodies 3 and 8 and the fixed shaft 4 are connected. As a result, a sleeve 5 can be removed only by dismantling the fixed body 3.

Abstract: A method of estimating the blood flow rate of a heart ventricle assist device which is positioned externally of, or implanted in, a patient. The assist device comprises a blood pump having a rapidly rotating, electrically powered impeller, and comprises briefly interrupting power to the impeller to cause its rotation to slow. From this, blood viscosity can be estimated, which viscosity is used to obtain real time, estimated blood flow rates and pressure heads.

Abstract: A rotary blood pump may include one or more motor stators overlying exterior surfaces of a wall defining a pumping chamber. A rotatable impeller within the pumping chamber may have a hydrodynamic thrust bearing surface adapted to constrain a position of the impeller along an axis of rotation relative to the wall when the impeller is rotating about the axis of rotation. The impeller position may then be constrained without requiring a constant polarity magnetic force to be applied in the axial direction from a fixed position of the housing.

Abstract: A magnetic impeller for a blood pump such as a magnetically driven, rotary ventricular assist device for pumping blood of a patient, the impeller comprising a magnetic alloy including platinum, cobalt, and boron.

Abstract: A heart assist device comprising a rotary pump housing having a cylindrical bore, a pumping chamber and a motor stator including an electrically conductive coil located within the housing and surrounding a portion of the cylindrical bore. A rotor has a cylindrical shaft, at least one impeller appended to one end of the shaft, and a plurality of magnets located within the shaft. The rotor shaft is positioned within the housing bore with the magnets opposite the motor stator, and the impeller is positioned within the pumping chamber. The housing bore is closely fitted to the outer surface of the shaft forming a hydrodynamic journal bearing, with the pumping chamber and journal bearing connected by a leak path of blood flow between the pumping chamber and the journal bearing. A backiron of the motor stator attracts the rotor magnets to resist longitudinal displacement of the rotor within the housing during operation.

Abstract: A blood pump is temporarily operated at a low rotational speed lying below a design rotational speed. This involves a risk of thrombogenesis since flow detachments may occur at blades of an impeller of the rotary blood pump. For eliminating deposits at said impeller, the rotational speed of said pump is temporarily increased to the design rotational speed. Alternatively, said pump alternately operates at said design rotational speed and a low rotational speed, and this pulsed operation is synchronized with the heart rate.

Abstract: In a flow rate estimation method of a blood pump, a general flow rate estimation formula which includes a correction term is formed based on a plurality of blood pumps. Measured data obtained from an objective blood pump implanted inside a patient is substituted into the correction term, thus forming a flow rate estimation formula of the objective blood pump. The flow rate Q of the objective blood pump is estimated based on the flow rate estimation formula and the values of the rotational speed N and the consumption current I of the motor of the objective blood pump, and the attribute data Z of the blood of the patient.

Abstract: According to the invention the rotary pump consists of an external gear (13) with internal teeth (16) in the form of a squirrel cage, and an internal gear (9), housed in an off-centre manner in the interior of said external gear (13) and fitted with external teeth (9D) intermeshing with said internal teeth (16) and consisting of a number of inferior teeth of a unit with the number of teeth of the later. The rotation means of said external teeth (13) comprise at least a bearing (11, 12) centrally laid out in a flange end (14,15) of said aforementioned external gear (13) and the aforementioned external gear (13) is at least partly dismantled in order to introduce said internal gear (9).

Abstract: One aspect of an intravascular ventricular assist device is an implantable blood pump where the pump includes a housing defining a bore having an axis, one or more rotors disposed within the bore, each rotor including a plurality of magnetic poles, and one or more stators surrounding the bore for providing a magnetic field within the bore to induce rotation of each of the one or more rotors. Another aspect of the invention includes methods of providing cardiac assistance to a mammalian subject as, for example, a human. Further aspects of the invention include rotor bodies having helical channels formed longitudinally along the length of the body of the rotor where each helical channel is formed between peripheral support surface areas facing radially outwardly and extending generally in circumferential directions around the rotational axis of the rotor.

Abstract: An apparatus, system, and method for assisting a heart in circulating blood that has been damaged, for example, by a myocardial infarction. In at least one aspect, an apparatus, system, and method are used for inserting a single cannula assembly comprising at least an inner and outer cannula into the left ventricle, advancing the inner cannula portion of the cannula assembly past the aortic valve, and into the aorta without requiring a secondary cannula insertion through an external portion of the aorta. In another aspect, an intraventricular assistant device (IVAD) having a motor and impeller can be inserted directly into the heart, such as in the left ventricle. The IVAD uniquely provides a pump within the heart through a single insertion that can reduce thrombosis and lessen the complexities typically associated with such efforts.

Abstract: Rotary hydrodynamic blood pumps have been used to treat over a thousand patients. The Jarvik 2000 has supported a patient for seven years and uses blood immersed bearings washed by high flow to avoid excessive thrombus formation. This permits the pump to be very simple and small. Nonetheless, the present Jarvik 2000 bearings and all other mechanical blood immersed bearings of the prior art have a supporting structure that predisposes to thrombus adjacent to the bearings. The present invention provides a bearing structure that eliminates this predilection site for thrombus formation, and may provide indefinite thrombus free operation. The rotor of the preferred embodiment includes a tapered hub fabricated of wear resistant material supported by three posts at each end of the rotor, upon which the rotor rotates. Blood washes the unobstructed spaces between the posts to prevent the accumulation of a torus of thrombus that could enlarge excessively.

Abstract: A blood pump including a ultrasonic sensor mounted in or on a blood contacting surface of said blood pump. The ultrasonic sensor measures blood velocity and reports information to a blood pump controller and wherein the ultrasonic sensor is directed to measure blood velocity in an inflow cannula connected to the blood pump.

Abstract: The invention relates to a device for axially conveying body fluids. The aim of the invention is to embody the inflow and outflow area of an axial pump in such a way that the flow is not separated even when it is diverted, thereby maintaining a substantially non-disrupted flow profile.

Abstract: A foldable intravascularly insertable blood pump comprises a rotatable impeller provided with vanes, a flexible shaft extending through a catheter and adapted to drive said impeller, and an envelope enclosing said impeller. For simplifying the technical setup of the blood pump and enhancing its robustness, the impeller comprises radially delivering vanes. The envelope comprises an annular bulge in the region of the impeller, wherein between the radially outer ends of the vanes and the envelope an annular deflection channel is defined. The impeller and the envelope are adapted to be folded by relative displacement of the shaft and the catheter.

Abstract: Since disruptive forces can be continuously exerted upon a rotor during a pulsatile flow through a pump with a magnetically mounted rotor (permanent magnets and addition control current coils), it is necessary to adjust position i.e. modify axial rotor position very quickly. The control current should only result in small amounts of losses. According to the invention, the current is pulse-width modulated by the control current coils by means of a set value predetermined by a controller which is arranged downstream from a position sensing system. If the set value is high, it is switched to a higher voltage level and the real value of the position sensing system is stored for a defined period of time, respectively beginning with the switching flank of the control current, and the position sensing system is disconnected during said period of time.

Abstract: A blood pump has an impeller rotatably disposed and magnetically suspended within a cavity of a stator by a plurality of magnetic bearings (passive permanent and active electromagnetic) having impeller magnets on the impeller and stator magnets or coils/poles on the stator. A motor includes impeller magnets on the impeller and coils/poles associated with the stator. A single, annular blood flow path extends axially through the cavity between the impeller and the stator, and between the impeller magnets on the impeller and the stator magnets or the coils/poles on the stator.

Abstract: In a centrifugal flow blood pump, usable in left ventricular assist applications, blood is pumped from an inlet (16) to an outlet (22) by a primary impeller (18). A portion of the blood that enters the pump follows a secondary channel (24) where a secondary impeller (70) routes the blood to lubricate a bearing between an impeller assembly (14) and a post formed by a component of the pump housing. The unique shape of the secondary impeller (70) prevents blood stagnation and provides for a well-washed fluid bearing.

Abstract: A minimal intrusive cardiac support apparatus is disclosed which requires only one incision into a main blood vessel or heart chamber. The apparatus includes a pair of generally coaxial and slideably arranged cannulae (one inner and one outer) communicatively coupled to a blood pump for providing right-heart and/or left-heart cardiac support during cardiac surgery. Optional balloons may be mounted on the outside of the inner and outer conduits which can be selectively inflated to seal off the sides surrounding vessel or to deliver cooling fluid or medication to the surrounding tissue. Using the apparatus, a method of pumping blood through the body is also disclosed.

Abstract: A blood pump system includes a housing having an inlet port and an outlet port, a rotor rotated in the housing for pumping blood, and a motor for rotating the rotor. The blood pump system includes a motor current measuring function, and a backflow detecting function for detecting a backflow of blood by use of the motor current value continuously measured by the motor current measuring function.

Abstract: An inflatable circulation assist device is disclosed consisting of an inflatable stator housing an impeller with inflatable blades of varying shapes and sizes. The invention is introduced into the patient percutaneously. The circulation assist device is a small pump packaged into a compact form that is attached to a long flexible driveshaft. The pump is inserted along a guidewire to a target location, and then the pump is inflated. The circulation assist device's exterior is designed to expand only so much as to closely fit whatever cardiovascular system element in which it is placed for operation. The vascular assist device can be expanded either by inflation with a fluid. The driveshaft, which connects to the circulation assist device's impeller and extends outside the patient's body, is rotated by an external motor. After the circulation assist device is no longer needed, it is collapsed into a compact form and removed from the patient percutaneously.

Abstract: A surgical pump suitable for bodily fluids, normally blood, usable in the course of surgical interventions as an alternative to the traditional CPB (cardio pulmonary bypass) making use of external blood pumps. It consists of an intake cannula (20) which is inserted with its first (distal) end in a first vessel, an outflow cannula (30) coaxial for some length with, and larger than the first cannula, which is inserted with its first (distal) end in a second vessel, both second ends of the coaxial cannulas being connected with a pump housing (52) having an inlet (62) for the inner cannula and outflow windows (64) for the outer cannula, a rotor impeller (70) housed in the housing and connected with an electric motor (80) rotating coaxially below the pump housing, the housing having inner (56) and outer (59) passageways which allow inflow, change of flow direction (reversal) and outflow of the fluid, thus producing two coaxial counter flowing flows in the coaxial cannulas.

Abstract: The present invention relates to systems and methods for transporting fluid between different locations within a body cavity and, in one particular application, systems and methods for transporting fluids to maintain at least partial blood flow through a protected blood flow path within the right and/or left side of the heart during surgery. The protected blood flow path may be established by positioning one or more conduits within at least a portion of the right and/or left sides(s) of the heart. At least partial blood flow may be maintained through the protected blood flow path by the pumping action of a blood pump disposed within the conduit.

Abstract: A minimal intrusive cardiac support apparatus is disclosed which requires only one incision into a main blood vessel or heart chamber. The apparatus includes a pair of generally coaxial and slideably arranged cannulae (one inner and one outer) communicatively coupled to a blood pump for providing right-heart and/or left-heart cardiac support during cardiac surgery. Optional balloons may be mounted on the outside of the inner and outer conduits which can be selectively inflated to seal off the sides surrounding vessel or to deliver cooling fluid or medication to the surrounding tissue. Using the apparatus, a method of pumping blood through the body is also disclosed.

Abstract: The invention provides a device for the axial delivery of fluidal mediums, which outer diameter is not or only insignificantly larger than the diameter of the fluid carrying pipe, which reduces to a large extent a shearing and vortexing of the fluid. A device for the axial delivery of fluidal mediums, having a tubular hollow body arrangement, in which delivery area, an impeller (9) with a blading, which can be rotated, is arranged and also has a fluid directional means. A motor (2), at least one impeller (9) which can be rotated, and at least one motor mounting (14) are arranged in a tubular hollow body (1) of the hollow body arrangement. The impeller (9) is connected axially force-fittingly and/or form-fittingly to the motor (2).

Abstract: A magnetic bearing wherein axially spaced combinations of permanent magnets on a rotor and stator are polarized to levitate the rotor and positioned with the rotor magnets offset axially outwardly (or inwardly) of the stator magnets to allow a force balance to be achievable to bear axial thrust. An electrically energizable coil modulates magnetic flux between the respective stator and rotor magnets for each combination. A first electrical circuit regulates electrical energy to the coils for maintaining a reference position of the rotor. A second electrical circuit compares feed-back of electrical energy to at least one of the coils with a reference electrical energy of about zero amps or volts and integrates the differences until the difference is about zero to provide a signal to modify the reference position, whereby to attain a zero force balance position wherein the current which must be supplied to the coils may be reduced to near zero.

Abstract: A blood pump having a pump housing and an impeller disposed in the housing and driven by an electric drive includes at least two connection devices directly disposed at the housing for connection to an artery outside the heart such as for example a suture ring or a vascular prosthesis and configured in such a manner to realize a direct connection of the artery to the pump housing, and wherein a pump conduit can be implanted into the aorta ascendens for relieving the left ventricle and in the truncus pulmonalis or into the pulmonalis furcation for reliving the right cardiac ventricle and other blood vessels for improving the blood circulation or elevating the pressure in a certain vascular section.

Abstract: A bioreactor with a reaction container (1, 1a, 1b, 1c) for a substance (C) to be acted upon with a medium has a pump (5, 5a, 5b, 5c, 5d) for conveying the medium. The pump is designed as an expendable pump or, respectively, parts (53d, 54d, 55d) of the pump are designed as expendable parts.

Abstract: An intravascular miniature stent pump comprising an intravascular stent for implantation at an implant site within a blood vessel and a miniature pump mounted on the stent, wherein the pump allows an adequate blood flow to prevent clotting within a lumen of the stent, and wherein the blood flow is equal to or greater than a blood flow at the implant site before implantation.

Abstract: An artificial heart has a driving section, a nozzle section, a pump section for insertion into a ventricle of a human heart, and a sealing section forming a seal for a driving shaft extending from the driving section for driving the pump section. A sealing liquid chamber filled with a sealing liquid is formed around the driving shaft between the sealing mechanism and the driving section. The sealing liquid in the sealing liquid chamber maintains the sealing mechanism in a liquid-tight state and lubricates the sealing mechanism, whereby blood is prevented from entering the driving section. Even if blood happens to enter the driving section, the blood is mixed with the sealing liquid and does not coagulate. Thus, the operation of the artificial heart is not suppressed.

Abstract: Pump and cannula systems inserted through the right side and/or left side of the heart provide protection against collapse of the heart chambers and veins and arteries and provide supplemental blood flow through same to enable beating heart bypass surgery on all vessels of the heart, including lateral and posterior vessels. The invention eliminates the use of cardiopulmonary bypass (CPB) machines. The invention further provides stents adapted for protecting from vein, artery, atrium and/or ventricle collapse during beating heart bypass surgery.

Abstract: An artificial heart has a driving section, a nozzle section, a pump section for insertion into a ventricle of a human heart, and a sealing section forming a seal for a driving shaft extending from the driving section for driving the pump section. A sealing liquid chamber filled with a sealing liquid is formed around the driving shaft between the sealing mechanism and the driving section. The sealing liquid in the sealing liquid chamber maintains the sealing mechanism in a liquid-tight state and lubricates the sealing mechanism, whereby blood is prevented from entering the driving section. Even if blood happens to enter the driving section, the blood is mixed with the sealing liquid and does not coagulate. Thus, the operation of the artificial heart is not suppressed.

Abstract: A blood pump for assisting a heart is provided having a stator and a rotor. The rotor is magnetically radially supported creating a suspension gap between the stator and the rotor. The rotor can be supported axially by a Lorentz force bearing and can be magnetically rotated. The stator can have a single or double volute pump chamber and the rotor can have an impeller portion for pumping blood. The rotor can have a center bore as a primary blood flowpath. The suspension gap can be a secondary blood flowpath. The blood pump can also have an axial position controller and a flow rate controller. The axial position controller can cause the axial bearing to adjust the position of the rotor. The flow rate controller can have a member for measuring a dimension of a heart ventricle to control the flow rate to avoid overly distending or contracting the ventricle. A method of operating the flow rate controller to create a pulsatile flow rate is also provided.