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WO2001091828A2 - Regulation du debit gauche-droite dans une prothese cardiaque a deux chambres - Google Patents

Regulation du debit gauche-droite dans une prothese cardiaque a deux chambres Download PDF

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Publication number
WO2001091828A2
WO2001091828A2 PCT/US2001/017247 US0117247W WO0191828A2 WO 2001091828 A2 WO2001091828 A2 WO 2001091828A2 US 0117247 W US0117247 W US 0117247W WO 0191828 A2 WO0191828 A2 WO 0191828A2
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WO
WIPO (PCT)
Prior art keywords
hydraulic
pressure
pumping
patient
flow
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2001/017247
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English (en)
Other versions
WO2001091828A3 (fr
Inventor
Robert W. Fasciano
Farhad Zarinetchi
Robert T. V. Kung
Sourav K. Bhunia
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Abiomed Inc
Original Assignee
Abiomed Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/687,040 external-priority patent/US6527698B1/en
Priority claimed from US09/689,935 external-priority patent/US6540658B1/en
Application filed by Abiomed Inc filed Critical Abiomed Inc
Priority to AU2001263482A priority Critical patent/AU2001263482A1/en
Publication of WO2001091828A2 publication Critical patent/WO2001091828A2/fr
Publication of WO2001091828A3 publication Critical patent/WO2001091828A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/80—Constructional details other than related to driving
    • A61M60/855—Constructional details other than related to driving of implantable pumps or pumping devices
    • A61M60/869—Compliance chambers containing a gas or liquid other than blood to compensate volume variations of a blood chamber
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/10—Location thereof with respect to the patient's body
    • A61M60/122—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
    • A61M60/165—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart
    • A61M60/178—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
    • A61M60/183—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices drawing blood from both ventricles, e.g. bi-ventricular assist devices [BiVAD]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/20—Type thereof
    • A61M60/205—Non-positive displacement blood pumps
    • A61M60/216—Non-positive displacement blood pumps including a rotating member acting on the blood, e.g. impeller
    • A61M60/226—Non-positive displacement blood pumps including a rotating member acting on the blood, e.g. impeller the blood flow through the rotating member having mainly radial components
    • A61M60/232—Centrifugal pumps
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/40—Details relating to driving
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/40—Details relating to driving
    • A61M60/403—Details relating to driving for non-positive displacement blood pumps
    • A61M60/408—Details relating to driving for non-positive displacement blood pumps the force acting on the blood contacting member being mechanical, e.g. transmitted by a shaft or cable
    • A61M60/411—Details relating to driving for non-positive displacement blood pumps the force acting on the blood contacting member being mechanical, e.g. transmitted by a shaft or cable generated by an electromotor
    • A61M60/416—Details relating to driving for non-positive displacement blood pumps the force acting on the blood contacting member being mechanical, e.g. transmitted by a shaft or cable generated by an electromotor transmitted directly by the motor rotor drive shaft
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/50—Details relating to control
    • A61M60/508—Electronic control means, e.g. for feedback regulation
    • A61M60/515—Regulation using real-time patient data
    • A61M60/531—Regulation using real-time patient data using blood pressure data, e.g. from blood pressure sensors
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/80—Constructional details other than related to driving
    • A61M60/802—Constructional details other than related to driving of non-positive displacement blood pumps
    • A61M60/833—Occluders for preventing backflow
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/10—Location thereof with respect to the patient's body
    • A61M60/122—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/10—Location thereof with respect to the patient's body
    • A61M60/122—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
    • A61M60/126—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable via, into, inside, in line, branching on, or around a blood vessel
    • A61M60/148—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable via, into, inside, in line, branching on, or around a blood vessel in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/20—Type thereof
    • A61M60/247—Positive displacement blood pumps
    • A61M60/253—Positive displacement blood pumps including a displacement member directly acting on the blood
    • A61M60/268—Positive displacement blood pumps including a displacement member directly acting on the blood the displacement member being flexible, e.g. membranes, diaphragms or bladders
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/40—Details relating to driving
    • A61M60/424—Details relating to driving for positive displacement blood pumps
    • A61M60/427—Details relating to driving for positive displacement blood pumps the force acting on the blood contacting member being hydraulic or pneumatic
    • A61M60/432—Details relating to driving for positive displacement blood pumps the force acting on the blood contacting member being hydraulic or pneumatic with diastole or systole switching by stopping or reversing the blood pump operating at a much higher cyclical speed than the heart beat
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/50—Details relating to control

Definitions

  • This invention relates in general to artificial hearts and more particularly to an artificial heart system that will respond to varying physiological demand and includes mechanisms accommodating the actual flow imbalance between pulmonary and systemic circulations.
  • the volume of blood flow pumped by the left side of the heart is higher than that pumped by the right side of the heart.
  • This difference is largely attributable to a circulatory pathway known as the bronchial shunt.
  • This flow originates in the left arterial system, passes through the bronchial tissue and then returns directly to the left atrium. This difference typically appears to be up to about ten percent of cardiac output with the left side flow always greater than the right side flow.
  • Artificial heart systems must account for this inherent physiological circulatory imbalance.
  • sources of flow imbalance can be man-made. For example, differences in regurgitation through artificial valves provided on the left and right sides can introduce a flow imbalance. Artificial heart systems must account for these types of circulating imbalances as well.
  • RAP right atrial pressure
  • RVP right atrial pressure
  • RVP right atrial pressure
  • LAP left atrial pressure
  • a biventricular cardiac prosthesis controlling LAP within a physiologic range is important. If LAP is consistently high, not only can the atrium itself be damaged, but the high pressure can, in extreme cases, result in pulmonary edema or excessive fluid retention of the lungs. Also, when LAP is too low, atrial damage, air emboli and in-flow limitations can result.
  • Kung provides a biventricular cardiac prosthesis having left and right side hydraulic chambers and left and right side blood pumping chambers which replace the natural ventricles in a patient with a failing heart. Also included is a reciprocating hydraulic pump that pumps hydraulic fluid back and forth between the right and left hydraulic chambers to drive right and left systole.
  • Kung further provides a hydraulic compliance chamber having a flexible membrane coupled to the left atrial blood.
  • hydraulic fluid is at least partially shunted to the hydraulic flow of the right pump, thus reducing the stroke volume and output of the right side.
  • the Kung device relies on pressure in the hydraulic pumpmg chambers for pressure representative of respective atrial pressures. While this approximation of atrial pressure is sufficient to improve flow balance under a variety of conditions, the approximation can be less accurate under high blood flow conditions.
  • the invention provides a biventricular cardiac prosthesis having a flow control system for maintaining left atrial pressure within physiologic bounds. That is, the prosthesis flow control is responsive to left atrial pressure to maintain that pressure within physiologic bounds.
  • a method for controlling a biventricular cardiac prosthesis measures a patient's left atrial pressure, determines whether the left atrial pressure is outside of a desired tolerance about a desired left atrial pressure value, and derates right side blood flow to maintain left atrial pressure within the tolerance.
  • An apparatus of this aspect of the invention includes left and right pumping sections, a right pumping section pumping volume derating element, and a control element controlling the derating of right side flow to maintain a patient's left atrial pressure within physiologic bounds. The measurement of left atrial pressure may be taken directly, or indirectly as described hereinbelow.
  • the invention provides a method and apparatus for balancing flow by derating right side flow to hold a patient's left atrial pressure close to the patient's right atrial pressure, that is, the difference between left atrial pressure and right atrial pressure is close to zero.
  • An apparatus of this aspect is a cardiac prosthesis that includes left and right hydraulic pumping chambers and a reciprocating hydraulic pump for alternately driving left and right systole.
  • a control signal can be derived from the difference in pressure between the left and right hydraulic pumping chambers, and the control signal is applied to adjust the flow of the right hydraulic pumping chamber to maintain the control signal close to zero.
  • the invention provides a system and method for measuring the difference between right and left atrial pressures in a patient having a biventricular prosthesis.
  • This system includes a prosthesis selected so as to have similar flow or pressure drop characteristics for blood inflow on its left and right sides and has one or more pressure transducers for measuring average diastolic pressures in its left and right pumping chambers. The difference between left and right atrial pressure in a patient having the prosthesis installed can then be determined from the difference in pressure between the left and right pumping chambers.
  • an energy converter having a hydraulic pump and a fluid switch drives left and right systole in the prosthesis.
  • a single pressure transducer is provided in the hydraulic pump inlet to measure both left and right diastolic pressures. In this embodiment of the invention, the use of a single transducer to measure both pressures and then taking the difference between the two signals results in the desired measurement signal while eliminating any inaccuracies due to "drift" that may occur in the transducer over time.
  • the hydraulic pump is stopped for a short period of time to allow the hydraulic pressure in the left and right pumping chambers to equilibrate. Separate transducers measuring left and right hydraulic pressures are then polled and a difference is taken as an offset. This offset is then applied to difference measurements taken during operation of the prosthesis as a representation of transducer drift over time.
  • the speed of the hydraulic pump is varied according to a profile rather than stopped at the end of systole.
  • a total artificial heart with controlled left and right flow has left and right pumping sections, each having a blood pumping chamber connectable to a patient's atrium for blood inflow, and a hydraulic pumping section.
  • a reciprocating pump causes hydraulic fluid to flow back and forth between the right and left hydraulic pumping sections.
  • a hydraulic balance chamber responsive to the patient's left atrial pressure is in hydraulic communication with the right hydraulic pumping section by means of a hydraulic coupling with flow through the coupling between the right hydraulic pumping section and the hydraulic balance chamber affecting the stroke volume of the right hydraulic pumping section.
  • the hydraulic coupling has a variable flow resistance that is adjustable to maintain a desired control of flow between the right and left pumping sections.
  • the resistance to flow in the coupling is adjusted by adjusting an occluder that effectively restricts a cross-sectional dimension of the coupling to increase resistance to flow, or alternatively increases a cross- sectional dimension to reduce resistance to flow.
  • the total artificial heart is designed as described above so that the difference between left and right pumping section pressure is representative of the difference between left and right atrial pressure in a patient having the total artificial heart implanted.
  • a signal representing the difference between left and right hydraulic pumping section pressures can then be used to automatically adjust the occluder to modify the right hydraulic section stroke volume to maintain the patient's left atrial pressure close to the patient's right atrial pressure, and thus within physiologic bounds.
  • a total artificial heart has left and right pumping sections, with a hydraulic balance chamber hydraulically coupled to a hydraulic pumping section of the right side.
  • the hydraulic coupling includes a variable flow resistance that is adjustable to maintain balanced flow between the right and left pumping sections.
  • the variable flow resistance can be provided by a variable orifice having a movable flow restrictor.
  • the movable flow restrictor has a first side coupled to a pressure source representative of left atrial pressure and a second opposed side coupled to a pressure source representative of right atrial pressure so that the movable flow restrictor moves in response to differences between the two atrial pressures.
  • the hydraulic balance chamber is coupled to a patient's left atrium to serve as a source representative of left atrial pressure, and the right hydraulic section serves as a source representative of right atrial pressure.
  • Figure 1 illustrates diagrammatically a biventricular cardiac prosthesis of the invention during right side systole
  • Figure 1A illustrates diagrammatically the prosthesis of Figure 1 during left side systole
  • Figure 2 illustrates an energy converter useful with the prosthesis of Figure 1
  • FIG 3 illustrates an atrial blood flow conduit and hydraulic balance chamber useful with the prosthesis of Figure 1;
  • Figure 4 illustrates an adjustable occluder useful with the prosthesis of Figure l
  • FIGS 5 and 5A illustrate pressure sensor embodiments useful with the prosthesis of the invention
  • Figures 6 and 6A illustrate energy converters useful with the prosthesis of Figure 1 having two and one pressure transducers, respectively;
  • Figure 7 is a representation of a pressure reading produced by a pressure sensor in the prosthesis of the invention;
  • Figure 8 is a diagrammatic view of a passively controlled occluder useful with the prosthesis of the invention.
  • Figure 9 is an exploded view of an embodiment of the occluder of FIG. 8;
  • Figure 10 is a cross sectional view of the occluder of FIG. 9;
  • Figure 11 is a cross sectional view of an additional passively controlled occluder embodiment useful with the invention.
  • Figure 12 is a chart showing improved flow in a prosthesis of the invention.
  • Figure 13 is a chart showing improved pressure characteristics in a prosthesis of the invention.
  • FIGS. 1 show the system during right side systole
  • 1A shows the system during left side systole
  • left blood pump 10 and right blood pump 20 are hydraulically connected to an energy converter 32 which includes both a fluid switch and a hydraulic pump as will be further described below.
  • the left side pump 10 includes a blood flow pumping chamber 11 having a blood input section 18 from the left atrium and a blood output port 14 to the aorta.
  • blood input sections are constructed as atrial cuffs, which can be made, for example, from velour, and more particularly, from Dacron ® , that connect the blood pumping chamber to the patient's atrium.
  • Blood valves 40 and 41 such as trileaflet valves, have the normal valving function for the blood flow into and out of the blood pumping chamber 11.
  • Pump 10 also includes a hydraulic pumping section 16 which is fluidically coupled to the hydraulic pump 32.
  • Right side pump 20 is constructed similarly to left side pump 10, having a blood pumping chamber 21 coupled between the right atrium at its blood input port 22 and the pulmonary artery at its blood output port 24 by means of blood valves 45 and 43.
  • This pump also includes a hydraulic pumping section 26 fluidically coupled to the energy converter 32.
  • an exemplary energy converter 32 includes a hydraulic pump 46 which is coupled through a fluid switch 48a, 48b to the hydraulic sections 16 and 26.
  • the fluid switch and hydraulic pump in energy converter 32 are controlled by a controller 34 which receives electrical power from a battery 15 and control signals from sensors 36.
  • the . hydraulic pump 46 is a centrifugal flow pump with a sleeve valve 48a, 48b which can be electrically switched.
  • the energy converter 32 is drawing hydraulic fluid from right hydraulic section 26 and directing it to left hydraulic section 16.
  • energy converter 32 includes an inlet port 47 from the right hydraulic section 26 and an outlet port 49 to the left hydraulic section 16.
  • the hydraulic pump 46 a centrifugal pump driven by motor 51, draws hydraulic fluid into the energy converter 32 through inlet port 47 from the right hydraulic section 26, and expels the hydraulic fluid out through outlet port 49 to the left hydraulic section 16.
  • Energy converter 32 also includes and inlet 53 from the left hydraulic section 16 and an outlet 55 to the right hydraulic section 26, but these ports are blocked by an inlet blocking portion 48a and an outlet blocking section 48b of the fluid switch.
  • the position of the blocking sections 48a, 48b of the fluid switch are reversed so that inlet blocking portion 48a blocks the inlet 47 from the right hydraulic section 26 and the outlet blocking portion 48b blocks the outlet 49 to the left hydraulic section 16.
  • this switching may be accomplished by rotating the fluid switch 48a, 48b 180°.
  • the system of the invention illustrated in FIGS. 1 and 1A also includes a balance chamber 28 responsive to left atrial pressure.
  • Hydraulic balance chamber 28 is associated with the atrial blood input 18 of the left pump 10 and is fluidically coupled through conduit 30 to the right side hydraulic section 26.
  • the volume of hydraulic balance chamber 28 is small compared to the volume of hydraulic sections 16 and 26 (typically a 1:5 ratio).
  • Construction of an exemplary hydraulic balance chamber 28 is illustrated in FIG. 3.
  • a blood conducting conduit 59 connects atrial blood flow from the left atrium, via blood input 18 constructed as an atrial cuff for suturing to a patient's left atrium, and left side blood pumping section 11.
  • conduit 59 it is preferable for conduit 59 to have low resistance to flow so that the blood pressure in conduit 59 is effectively equal to left atrial blood pressure. Under these conditions, diaphragm 60 is effectively responsive to blood pressure within the atrium.
  • Hydraulic balance chamber 28 is separated from the patient's blood flow by diaphragm 60 and is hydraulically coupled to the right side hydraulic chamber 26 through conduit 30.
  • the position of the diaphragm 60, and thus the volume of the hydraulic balance chamber 28, varies in response to the difference between the left atrial blood pressure and the right hydraulic section 26 pressure.
  • construction of hydraulic chamber 28 may vary from the illustrated embodiment in keeping with the spirit of the invention.
  • hydraulic balance chamber 28 could be integral with the atrial cuff at blood input 18.
  • An occluder 35 (FIGs. 1 and 1A) is coupled to conduit 30 to vary the resistance to flow (R) between the right side hydraulic chamber 26 and the hydraulic balance chamber 28.
  • An exemplary occluder 35 is illustrated in FIG. 4.
  • Occluder 35 is located in line with conduit 30 into the right hydraulic chamber 26 and is mounted to a translation motor 52 that moves the occluder 35 in a direction at least partially transverse to the flow path of conduit 30.
  • the occluder 35 can be moved back and forth by translation motor 52 to vary the effective diameter of conduit 30, and thus affect hydraulic shunt flow resistance (R) through the conduit.
  • transaction motor 52 has a rotating shaft 54 connected to a drive screw component 56 having external threads 58.
  • An occluding member 60 is threadedly engaged with the drive screw 56 so as to translate in a direction at least partially transverse to the flow path of conduit 30 upon rotation of the drive screw 56 in response to translation motor 52.
  • occluder devices could be used consistent with the spirit of the invention.
  • the location of the occluder along the length of the conduit could be changed, the occluder could be driven by a solenoid rather than a translation motor, the occluder could comprise an inflatable constrictor for varying the effective diameter of the conduit, or other means for varying resistance to flow could be employed.
  • the pumping cycle is as follows.
  • energy converter 32 is directing hydraulic fluid to left side hydraulic chamber 16, causing diaphragm 17 to move so as to expand the left hydraulic section 16.
  • the moving of diaphragm 17 increases the pressure of the blood in the left side blood pumping chamber 11, causing valve 40 to close, valve 41 to open, and blood from the pumping chamber 11 to be expelled into the aorta.
  • the right side blood chamber 21 is filled from the right atrium. If the blood volume filling the right pump from the right atrium is less than the volume ejected from the left side blood chamber the hydraulic balance chamber 28 adjusts its volume in response to increased left atrial pressure to accommodate this volume difference by virtue of hydraulic fluid flowing from the compensating hydraulic balance chamber 28 into the right hydraulic section 26.
  • the shunt flow (SF) of hydraulic fluid between the hydraulic balance chamber 28 and the right side hydraulic chamber 26 thus depends on the difference between left atrial pressure and right hydraulic pressure (LAP-RHP).
  • flow control is based on a control signal representing left atrial pressure (LAP) directly.
  • LAP left atrial pressure
  • a pressure transducer is implanted with the prosthesis so as to be responsive to LAP.
  • a pressure sensing system 70 is applied to the left atrium so that the transducer does not contact blood, or so that only a blood safe portion of the system contacts blood.
  • a housing 71 having a blood safe coating 72, such as a blood safe epoxy is implanted so as to contact blood in the left atrium.
  • a hole in the coating is filled with a blood safe filler material 74 that allows pressure to be transmitted through to a pressure transducer 76 mounted within the housing 71.
  • the filler material 74 must be non-toxic and non- thrombogenic, as well as supple enough to allow pressure to be transmitted to the transducer below.
  • One such material is ANGIOFLEXTM, available from ABIOMED, Inc. of Danvers, Massachusetts.
  • Transducer 76 then provides an electronic control signal representative of LAP which can be used to control flow to maintain LAP within physiologic bounds.
  • a second LAP sensor system 80 is illustrated in FIG. 5 A.
  • a housing 82 is covered by a blood contacting membrane 84.
  • a filler material 86 is provided in a hole in the housing 82 to transmit pressure to transducer 88.
  • a thin membrane 84 of non-toxic, non-thrombogenic material such as ANGIOFLEXTM can then be coated over the housing 82 and filler material 86.
  • a feedback control algorithm can be employed to control the system of FIG. 1 to maintain LAP within physiologic bounds.
  • the algorithm determines once in each adjustment interval period, for example every 25 beats, whether action needs to be taken to open or close the occluder 35 based on the patient's left atrial pressure. If LAP is within some tolerance around the desired LAP, no action need be taken. If LAP is out of tolerance with the desired LAP, then the occluder is adjusted until LAP is back within tolerance.
  • the occluder 35 is opened by a large step size, for example, by 6% . If the LAP is lower than a minimum setting, the occluder 35 is closed by a large step size. Alternatively, if LAP is larger than the desired value plus the tolerance but below the maximum, the occluder 35 is opened by a small step size, for example, by 2% . If LAP is lower than the desired value minus the tolerance, but is larger than the minimum, then the occluder 35 is closed by a small step size.
  • control algorithms could, for example, vary the step size proportionally with the distance of LAP from the desired value, or from the desired value plus or minus the tolerance.
  • open loop gain of the feedback loop can be increased by reducing the time interval for corrections and increasing the step sizes for adjusting the occluder.
  • the control circuitry may include a communications interface with an external control unit for the purpose of performing diagnostics, downloading historical performance data, or uploading new parameters for use in the control algorithm.
  • a pressure sensor or sensors can be placed within the cardiac prosthesis itself to generate a signal that accurately represents the difference between LAP and RAP. This signal can then be used in a feedback control algorithm to control the left-right flow in the prosthesis to maintain LAP within physiologic bounds.
  • sensors 66 FIG. 6
  • sensors 66 FIG. 6
  • a single pressure sensor 68 FIG. 6A
  • a control signal that can be used to maintain LAP within physiologic bounds.
  • This hydraulic shunt flow is sensitive to the difference between LAP and the right chamber hydraulic pressure during right diastole (RHP; as used herein, RHP and LHP (left hydraulic pressure) refer to the hydraulic chamber pressures during diastole).
  • RHP right chamber hydraulic pressure during right diastole
  • RAP represents the right atrial pressure. If RAP-RHP is close to zero, a properly designed low flow resistance ("R" is a low value) will result in a broad range of hydraulic shunt flow (between about 0 to 10% of the cardiac output) over a typical span of cardiac output flows (3 to 10 L/min) while mamtaining LAP to within about 5 mmHg of the RAP.
  • LAP- RAP SFx R- (RAP- RHP).
  • Adjustable occluder 35 is therefore used to vary the flow resistance R, and thus the value of SFxR in Equation (3).
  • a closed loop control system for adjusting R to maintain LAP approximately equal to RAP would involve measuring both LAP and RAP, with subsequent adjustment of R by either opening or closing the occluder to keep LAP - RAP ⁇ 5 mmHg.
  • two hydraulic pressure sensors 66 can be provided to continuously measure the left and right hydraulic pressure in chambers 26 and 16.
  • a difference between atrial pressure and pump pressure on each respective side of the heart develops in high flow conditions due to pressure drops through the valves and blood flow conduits.
  • These pressure drops can be estimated using well known "head loss" relationships for fluid flow through a system where, for a given fluid, the pressure drop is approximately proportional to the square of the fluid flow rate through the system.
  • RAP- RHP b(Q- SF) m
  • Equation 4 and 5 where Q is the total blood flow through the heart, n and m are exponents that are approximately equal to 2.
  • a and b are loss coefficients, which by component characteristics selection (flow lengths and diameters, valve characteristics, etc.) can be made nearly equal to each other.
  • LAP- RAP LHP- RHP+ (a- b)Q 2 + 2b SF Q- b SF 2
  • the measurement of LHP and RHP is preferably performed during the respective diastolic phase of the left and right pumping chambers.
  • averaging over an appropriate time duration 64 of diastolic pressure provides a good measure of the hydraulic pressures in the right and left side hydraulic chambers during diastole for application of Equation (6).
  • the size of averaging window 64 is selected to yield the best measurements. Noise in the pressure signal which may be present during switching from left to right pumping and vice versa can be eliminated by proper window selection. Normally, between 30% to 80% of diastole is used for averaging.
  • beat rate (BR) change rate of switching in the fluid switch of energy converter 32
  • ⁇ speed of the hydraulic pump of energy converter 32
  • One approach is to use one transducer 68 for the measurement of both sides of the diastolic pressure as illustrated in the energy converter 32 of FIG. 6A. This can be implemented by hydraulically connecting the single transducer to the inflow region 69 of the energy converter 32.
  • transducer 68 Because the fluid switch of the energy converter 32 directs hydraulic fluid from whichever hydraulic pumping chamber is currently in diastole, only diastolic pressures are measured by transducer 68. Transducer 68 can then be polled during left and right diastole at separate times, and a difference between the values representing left and right hydraulic pumping chamber diastole could be taken to provide a control signal for the system. Such a one transducer system would completely bypass the sensor drift problem, since only differences in pressures are used and the sensor drift would be the same for both measurements because the same transducer is used.
  • a real time calibration approach can be implemented in this situation.
  • An alternate real time calibration approach which requires no hydraulic pump
  • the 46 stoppage is to vary the motor 51 speed according to a predetermined profile, and record the pressure differences from each transducer.
  • the speed of motor 51 can stepwise slowed down at the end of systole when there is effectively no flow through the hydraulic pump 46.
  • the motor 1 speed step down can be in steps, for example, a few hundred RPMs in time steps of few tens of milliseconds. With no flow, the pressure difference ( ⁇ P) is proportional to the square of the motor speed ( ⁇ ):
  • the residual ⁇ P is the relative transducer offset.
  • the signals from the transducer or transducers representing left and right hydraulic pressure can be compared either digitally where the controller includes a microprocessor or other digital circuitry appropriate for this purpose, or in analog fashion, for example, using a comparator circuit to compare pressure signals from two transducers to result in a pressure difference control signal.
  • this control signal is representative of the difference between right and left atrial pressures.
  • the control signal can therefore be used to adjust occluder 35 to maintain the control signal at zero, resulting in difference between right and left atrial pressures that is less than 5 mmHg, thus maintaining LAP within physiologic bounds.
  • a cardiac prosthesis and occluder can also be configured to keep LAP close to RAP, and thus within physiologic bounds, by using a "passive" occluder.
  • a passive occluder refers to a device for changing the flow resistance of a hydraulic coupling based directly on the atrial pressures, rather than through an active controller that acts on an electronic signal representing the pressures.
  • Such a passive occluder which may be used in place of occluder 35 in the system of FIG. 1, is illustrated diagrammatically in FIG. 8, with a specific embodiment in an exploded view in FIG. 9 and in cross section in FIG. 10, and with a further specific embodiment illustrated in FIG. 11.
  • a passive occluder 110 includes a port 112 to the hydraulic balance chamber 28, and a port 114 to the right hydraulic chamber 26.
  • a piston 116 having a piston aperture 118 slides back and forth in a direction at least partially transverse to hydraulic fluid flow through the coupling 30 within a piston housing 120 that includes a piston housing aperture 122.
  • the piston 116 is positioned within the piston housing 120 so that the overlap between the piston aperture 118 and the piston housing aperture 122 defines an occluder orifice region 124 having a length dimension "d".
  • the orifice size is sensitive to the difference between the right and left atrial pressures.
  • the position of the piston 116 is in part governed by a spring 126 having a spring constant K providing a bias on one side of the piston, and a fluidic coupling 130 providing a pressure equal to the pressure in the hydraulic balance chamber (P HB ) on the opposite side of the piston.
  • a port 128 is also provided in fluid communication with the right hydraulic chamber, providing a pressure P HR on this side of the piston also.
  • a check valve 132 (illustrated as a ball valve in FIGs. 9 and 10) can also be provided proximate to hydraulic balance chamber port 130. Check valve 132 can mitigate the effects of right side systole on the motion of piston 132.
  • a solenoid can be added to further control the motion of piston 116.
  • a solenoid coil and piston can be configured so that upon energization of the solenoid coil, piston 116 moves so as to close and stop the flow of fluid through occluder 110.
  • the solenoid can be controlled by controller 34 (FIG. 1) so as to energize at appropriate times, such as, for example, when LAP (or LHP-RHP) is at the lower end of a target range.
  • A is the cross sectional area of the piston 116.
  • a second boundary condition can be defined for the upper pressure limit for LAP, where the orifice should be entirely open to maximize flow of hydraulic fluid to the hydraulic balance chamber and the derating of right side blood flow.
  • P HB is a good approximation of LAP
  • the orifice will be fully open when LAP equals or exceeds RAP by a predetermined amount corresponding to the difference between the desired LAP upper limit and average RAP, and the orifice will be fully closed when LAP is less than or equal to zero.
  • Flow of hydraulic fluid through the orifice can be described by:
  • w is the width of the orifice and wd is the area of the flow through the orifice.
  • the discharge coefficient is assumed to be unity.
  • Equation 15 and for d 0 or P ⁇ P HR ⁇ -P a :
  • the spring constant for the spring can be calculated from Equation (10).
  • the piston should not pulse significantly during a beat. Pulsing can be avoided if the movement of the piston is limited to less than 1 % of d 0 during half a beat. At 120 BPM, this time interval ⁇ t ⁇ 0.25 sec. To achieve this, the gap ( ⁇ ) between the variable orifice piston and its housing should be governed by:
  • Occluder 150 includes a port 152 to the hydraulic balance chamber 28, and a port 154 to the right hydraulic chamber 26.
  • piston 156 Rather than carrying an orifice that is in-line with the flow of hydraulic fluid through the occluder, piston 156 carries a check valve member 158 that is generally transverse to the flow of hydraulic fluid in the coupling 162. The location of piston 156 depends on the constant of spring 160 and the right hydraulic pressure on one side of the check valve member 158, and the hydraulic balance chamber pressure on the opposite side of the check valve member to set flow resistance through the device.
  • an occluder system 150 may include a parallel path for filling the hydraulic balance chamber without resistance during right systole by providing a balance chamber filling port 180 having a check valve 182.
  • Check valve 182 allows resistance free filling of the hydraulic balance chamber, but forces the balance chamber to be emptied through the variable orifice through a resistance that is responsive to LAP-RAP.
  • This parallel path can be provided as part of the occluder system as illustrated in FIG. 11, or it can be a separate, parallel fluid coupling.
  • One advantage of this embodiment is that the effects of right systole on piston 156 and check valve member 158 need not be compensated for. That is, during right systole, right hydraulic chamber pressure will cause check valve member 158 to close fluid coupling 162 to the hydraulic balance chamber. In the embodiment of FIG. 9, this reaction to right side systole is checked by ball valve 132 and by the piston damping characteristics. In the embodiment of FIG. 11, however, because filling check valve 182 permits filling of the hydraulic balance chamber during right side systole even when check valve member 158 is closed, check valve member 158 can be allowed to open and close freely during the beating of the cardiac prosthesis.
  • a fail safe mechanism can also be incorporated into an occluder system of the invention by adding a small fixed orifice between the hydraulic balance chamber and the right hydraulic chamber with a fixed resistance of 40 mmHg/L/min so that if the movable piston jams, a mean flow of up to 0.2 to 0.3 L/min could be provided within physiologic pressures.
  • Scenario (c) is a case without variable orifice control. The figure shows a much broader range of flows through the orifice in response to changing LAP in the variable orifice scenarios (a) and (b), as compared to scenario (c) which does not employ variable orifice control.
  • FIG. 13 shows the variation of LAP-RAP for varying bronchial shunt flow rates with the variable orifice occluder (V.O.) compared to an adjustable occluder set to three different fixed openings, namely, full open, 15% open, and fully closed.
  • V.O. variable orifice occluder
  • FIG. 13 shows that the variable orifice occluder keeps LAP-RAP much closer to zero than the compared situations.

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  • Health & Medical Sciences (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Cardiology (AREA)
  • Hematology (AREA)
  • Mechanical Engineering (AREA)
  • Anesthesiology (AREA)
  • Biomedical Technology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Vascular Medicine (AREA)
  • Medical Informatics (AREA)
  • Prostheses (AREA)
  • External Artificial Organs (AREA)

Abstract

L'invention concerne une prothèse cardiaque biventriculaire comportant un système de régulation de l'équilibre du débit permettant d'équilibrer le débit sanguin à travers les côtés gauche et droit de la prothèse pour maintenir la pression atriale gauche d'un patient dans les limites physiologiques. Ladite prothèse peut être conçue de manière qu'elle présente des caractéristiques de débit selon lesquelles un signal représentant la différence entre des pressions de pompage hydraulique sur les côtés gauche et droit de la prothèse représente la différence entre les pressions atriales gauche et droite d'un patient porteur de ladite prothèse. Ledit signal peut servir de signal de commande permettant de commander la prothèse de façon que la pression atriale gauche soit à peu près égale à la pression atriale droite, dans les limites physiologiques. Une prothèse spécifique comporte des parties de pompage gauche et droite, comprenant chacune une chambre de pompage, une chambre pour fluide hydraulique, tandis qu'une pompe hydraulique alternative amène les systoles alternativement sur les côtés droit et gauche. Une chambre d'équilibrage hydraulique est couplée hydrauliquement avec la chambre pour fluide hydraulique droite et un obturateur réglable varie la résistance de débit à travers le couplage hydraulique. Ledit obturateur peut être réglé, soit sur la base du signal de commande afin de réduire le débit sanguin du côté droit et de parvenir à l'équilibre de pression souhaité, soit, sur la base de la communication fluidique, sur des sources de pression situées dans la prothèse, qui représentent les pressions atriales droite et gauche.
PCT/US2001/017247 2000-05-30 2001-05-25 Regulation du debit gauche-droite dans une prothese cardiaque a deux chambres Ceased WO2001091828A2 (fr)

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US20781600P 2000-05-30 2000-05-30
US60/207,816 2000-05-30
US68760300A 2000-10-12 2000-10-12
US09/687,040 US6527698B1 (en) 2000-05-30 2000-10-12 Active left-right flow control in a two chamber cardiac prosthesis
US09/689,935 2000-10-12
US09/687,603 2000-10-12
US09/687,040 2000-10-12
US09/689,935 US6540658B1 (en) 2000-05-30 2000-10-12 Left-right flow control algorithm in a two chamber cardiac prosthesis

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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6582375B2 (en) 2001-10-11 2003-06-24 University Of Cincinnati System for study of global uni-or bi-ventricular function of an explanted, reperfused heart
EP2078533A1 (fr) 2008-01-14 2009-07-15 Carmat Prothèse cardiaque monobloc implantable
CN114096205A (zh) * 2019-05-20 2022-02-25 V-波有限责任公司 用于产生房间分流管的系统和方法
CN114288013A (zh) * 2021-12-24 2022-04-08 杭州堃博生物科技有限公司 射频消融的控制方法、装置与射频消融组件
US12005214B2 (en) 2009-05-04 2024-06-11 V-Wave Ltd. Device and method for regulating pressure in a heart chamber
US12115328B2 (en) 2020-05-04 2024-10-15 V-Wave Ltd. Devices with dimensions that can be reduced and increased in vivo, and methods of making and using the same
US12186176B2 (en) 2009-05-04 2025-01-07 V-Wave Ltd. Shunt for redistributing atrial blood volume
US12186510B2 (en) 2015-05-07 2025-01-07 The Medical Research, Infrastructure And Health Services Fund Of The Tel-Aviv Medical Center Temporary interatrial shunts
US12226602B2 (en) 2019-04-03 2025-02-18 V-Wave Ltd. Systems for delivering implantable devices across an atrial septum
US12296122B2 (en) 2023-10-18 2025-05-13 V-Wave Ltd. Hybrid devices with dimensions that can be adjusted in vivo and methods of manufacturing thereof
US12303390B2 (en) 2004-02-03 2025-05-20 V-Wave Ltd. Device and method for controlling in-vivo pressure
US12311134B2 (en) 2017-03-03 2025-05-27 V-Wave Ltd. Asymmetric shunt for redistributing atrial blood volume
US12349912B2 (en) 2018-01-20 2025-07-08 V-Wave Ltd. Devices and methods for providing passage between heart chambers
US12369918B2 (en) 2020-11-13 2025-07-29 V-Wave Ltd. Interatrial shunt having physiologic sensor
US12453626B2 (en) 2009-05-04 2025-10-28 V-Wave Ltd. Shunt for redistributing atrial blood volume
US12465485B2 (en) 2011-07-28 2025-11-11 V-Wave Ltd. Interatrial shunts having biodegradable material, and methods of making and using same

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4369530A (en) * 1981-05-19 1983-01-25 Foxcroft Associates Hydraulically actuated cardiac prosthesis and method of actuation
US4888011A (en) * 1988-07-07 1989-12-19 Abiomed, Inc. Artificial heart

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6582375B2 (en) 2001-10-11 2003-06-24 University Of Cincinnati System for study of global uni-or bi-ventricular function of an explanted, reperfused heart
US12465488B2 (en) 2004-02-03 2025-11-11 V-Wave Ltd. Device and method for controlling in-vivo pressure
US12303390B2 (en) 2004-02-03 2025-05-20 V-Wave Ltd. Device and method for controlling in-vivo pressure
WO2009112662A3 (fr) * 2008-01-11 2009-11-05 Carmat Prothèse cardiaque monobloc implantable
EP2078533A1 (fr) 2008-01-14 2009-07-15 Carmat Prothèse cardiaque monobloc implantable
FR2926223A1 (fr) * 2008-01-14 2009-07-17 Carpentier Matra Carmat Prothese cardiaque monobloc implantable
US8702793B2 (en) 2008-01-14 2014-04-22 Carmat Implantable one-piece heart prosthesis
US12186176B2 (en) 2009-05-04 2025-01-07 V-Wave Ltd. Shunt for redistributing atrial blood volume
US12453626B2 (en) 2009-05-04 2025-10-28 V-Wave Ltd. Shunt for redistributing atrial blood volume
US12005214B2 (en) 2009-05-04 2024-06-11 V-Wave Ltd. Device and method for regulating pressure in a heart chamber
US12465485B2 (en) 2011-07-28 2025-11-11 V-Wave Ltd. Interatrial shunts having biodegradable material, and methods of making and using same
US12186510B2 (en) 2015-05-07 2025-01-07 The Medical Research, Infrastructure And Health Services Fund Of The Tel-Aviv Medical Center Temporary interatrial shunts
US12311134B2 (en) 2017-03-03 2025-05-27 V-Wave Ltd. Asymmetric shunt for redistributing atrial blood volume
US12349912B2 (en) 2018-01-20 2025-07-08 V-Wave Ltd. Devices and methods for providing passage between heart chambers
US12226602B2 (en) 2019-04-03 2025-02-18 V-Wave Ltd. Systems for delivering implantable devices across an atrial septum
CN114096205B (zh) * 2019-05-20 2024-05-24 V-波有限责任公司 用于产生房间分流管的系统和方法
CN114096205A (zh) * 2019-05-20 2022-02-25 V-波有限责任公司 用于产生房间分流管的系统和方法
US12251529B2 (en) 2020-05-04 2025-03-18 V-Wave Ltd. Devices with dimensions that can be reduced and increased in vivo, and methods of making and using the same
US12115328B2 (en) 2020-05-04 2024-10-15 V-Wave Ltd. Devices with dimensions that can be reduced and increased in vivo, and methods of making and using the same
US12369918B2 (en) 2020-11-13 2025-07-29 V-Wave Ltd. Interatrial shunt having physiologic sensor
CN114288013A (zh) * 2021-12-24 2022-04-08 杭州堃博生物科技有限公司 射频消融的控制方法、装置与射频消融组件
US12296122B2 (en) 2023-10-18 2025-05-13 V-Wave Ltd. Hybrid devices with dimensions that can be adjusted in vivo and methods of manufacturing thereof

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