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
  • A61M60/50—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
  • A61M60/10—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
  • A61M60/135—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 inside a blood vessel, e.g. using grafting
  • A61M60/139—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 inside a blood vessel, e.g. using grafting inside the aorta, e.g. intra-aortic balloon 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
  • A61M60/20—Type thereof
  • A61M60/295—Balloon pumps for circulatory assistance
• • 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
  • A61M60/465—Details relating to driving for devices for mechanical circulatory actuation
  • A61M60/489—Details relating to driving for devices for mechanical circulatory actuation the force acting on the actuation means being magnetic
  • A61M60/495—Electromagnetic force
• • 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
• • 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
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/33—Controlling, regulating or measuring
• • 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
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/33—Controlling, regulating or measuring
  • A61M2205/3303—Using a biosensor
• • 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
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/33—Controlling, regulating or measuring
  • A61M2205/3331—Pressure; Flow
  • A61M2205/3334—Measuring or controlling the flow rate
• • 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

Definitions

• the invention relates to a circuit for controlling an implantable cardiac assist pump of the backpressure balloon type.
• the technique of intra-aortic balloon counter pressure is well known for providing effective hemodynamic assistance to the left Ven- Tricule in cases of congestive heart failure: the balloon inserted into the descending branch of the aorta, is inflated during the diastolic phase of the cycle cardiac and thereby injects an additional volume of blood into the arterial network upstream and downstream of its position. Deflated during the consecutive cardiac systole, it reduces the load on the left ventricle and thus increases blood flow.
• the hemodynamic balance is positive: increase in the ejection fraction, decrease in the telediastolic pressure.
• the balloon delivers the additional energy that the ventricle is no longer able to provide, and the patient's condition is very significantly improved.
• Implanted systems have already been proposed which make it possible to implement this technique completely independently, as described for example in US-A-5 222 980, or in French application 96 00 949 filed on January 26, 1996 belonging to the ti ⁇ s books and even as this application and entitled pump assistance car- implantable heart of the counterpressure balloon type.
• the subject of the present invention is a control circuit for such an implantable cardiac assist pump which ensures control of the device such that its behavior is as physiological as possible, that is to say which overcomes cardiac insufficiency without requiring excessive or unnatural effort from the weakened myocardium, and which generates throughout the cardiovascular system a blood flow having a characteristic, in particular of pressure wave, as close as possible that of a healthy organism.
• Another object of the invention is to provide an evolutionary control of the pump, adapted to the actual hemodynamic demand of the patient so as to, on the one hand, limit the energy consumption of the implanted device and, on the other hand and especially minimize disruption the natural homeostatic équili ⁇ ber and thus avoid possible organic long-term complications following implantation of the pump.
• the invention provides a control circuit for an implantable cardiac assistance pump of the counter balloon type of the aforementioned type, that is to say comprising variable volume means cooperating with a volume, separate, through which the blood to cyclically change in a controlled manner the volume through which the blood circuit, characterized in that it comprises at least some of the means from the group comprising: means for sensing data representative of the aortic pressure; means to collect a data representative of the venous oxygen concentration; means for collecting a data representative of the aortic oxygen concentration; means for collecting a data representative of the heart rate; and means for collecting data representative of myocardial contractility.
• the circuit includes cardiac assistance control means that for controlling variable volume means, these control means comprising at least some of the means of the group comprising: means for controlling the speed of variation of said volume during the phase systolic myocardium; means for controlling the speed of variation of said volume during the dias ⁇ tohque phase of the myocardium; means for controlling the instant of start of said variation in volume during the systolic phase; and means for controlling the start time of said variation in volume during the diastohque phase;
• - cardiac assistance can, in a first embodiment, be a predetermined assistance, operating from: (i) a set of programmed values at rest from reference parameters, these parameters comprising at least one parameters among the speed of variation of the volume during the systolic phase of the myocardium, the speed of variation of the volume during the diastolic phase of the myocardium, the instant of start of said variation in volume during the systolic phase and the instant of the start of said variation in volume during the diastolic phase; and (ii) an algorithm for correcting at least one of said parameters as a function of the heart rate;
• the circuit includes means for collecting a given reest ⁇ sentative metabolic needs and / or the patient's physical activity;
• - cardiac assistance can, in a second embodiment, be automatic assistance, operating from: (i) a set, developed in real time, of representative data collected comprising at least the aortic pressure, the venous oxygen concentration, aortic oxygen concentration, frequency cardiac and myocardial contractility; (ii) a set of reference homologous parameters; (iii) deviations determined between said set of representative data and said reference set, and (iv) an algorithm for implementing means with variable volume as a function of the deviations thus determined.
• the algorithm for implementing the variable volume means advantageously ensures monitoring of cardiac assistance, in particular by applying assistance by successive approaches; in addition, cardiac assistance can make a correction to the data set produced in real time or to the reference set.
• Figure 1 is a schematic view showing the pump of the invention, its control circuit and the environment in which the entire device is located.
• FIG. 2 illustrates a modeling of the operation of the pump of FIG. 1.
• FIG. 3 is a representation of the characteristic of the pressure wave as a function of time over a cardiac cycle, with and without assistance by the pump of the invention.
• FIG. 1 there is shown an implantable cardiac assist pump, of the type known per se (for example from US-A-5,222,980 or French application 96 00949 above), the element of which main 10 comprises a rigid body 12, typically in the shape of a cylinder of revolution, open at its two ends and inserted into the descending aorta 14, the axis of the aorta and the axis of the body 12 being confused and these two elements being substantially the same diameter.
• main 10 comprises a rigid body 12 typically in the shape of a cylinder of revolution, open at its two ends and inserted into the descending aorta 14, the axis of the aorta and the axis of the body 12 being confused and these two elements being substantially the same diameter.
• the rigid body 12 contains a flexible membrane 16.
• the membrane 16 has at rest a homolo- gue of that of the body 12, so as to substantially match the shape of the latter, to which it is secured at both ends over its entire periphery.
• the increase in volume of the space 18 results from the injection of a hydraulic fluid (typically a biocompatible aqueous saline solution, for example a physiological serum) at one or, preferably, several points connected via of a pipe 22 to a variable pressure source 24 controlled by electronic control 26. It is also advantageous to provide a reservoir of hydraulic fluid 28 in the form of a septum accessible by the cutaneous route by means of a hypodermic needle to allow the adjustment of the volume and / or the salinity of the fluid, or to drain it.
• a hydraulic fluid typically a biocompatible aqueous saline solution, for example a physiological serum
• the subject of the invention is more particularly the circuit 26 which operates the pressure source 24.
• the pump can be modeled as shown in figure 2 in the m-th for- a piston 25 whose displacement in one direction or the other, results in a variation in the aortic volume 20.
• This variation artifi ⁇ cial of the volume 20 in the aorta 14 is comparable to the natural dilation of a healthy artery resulting from the inherent elasticity of the arterial walls, and of greater amplitude. More precisely, during the cardiac systole, the contraction of the myocardium 29 successively causes the rise in pressure of the left ventri ⁇ cule 30, the opening of the aortic valve 32 and the ejection of blood into the aorta 14.
• the heartbeat being such that the systole has a substantially shorter duration than the cycle cardia- that the speed of systolic ejection is even higher.
• the elasticity of the arteries avoids correspondingly requesting an excessive power from the ventricle to overcome the opposite charge by the inertia and the resistance of the blood column which it must set in motion and thus allows, in a way, deliver energy at a lower instantaneous flow rate during diastole.
• Heart failure is characterized by the inability of the ventri ⁇ cule to deliver the quantity of blood necessary for the organism due to lack of power, whether or not there is hardening of the arteries (but the hardening of the arteries particularly worsens the pathology).
• the cardiac assistance pump plays a double role: firstly, it artificially brings a complementary elasticity to the aorta, as indicated above, with the same benefit as that procured by the natural elasticity of the arterial network; secondly - and according to an original aspect - the pump has the possibility of providing an additional energy supply to the circulatory system during dias ⁇ tole.
• ⁇ being the surface of the piston and u (t) being the speed, variable as a function of time, of displacement of the piston during all or part of the system
• This volume of blood, stored in the pump during systole, is then reinjected into the aorta during the diastole D which follows systole, by reverse movement of the piston at speed v (t), also variable as a function of time and during all or part of the diastole D (this speed v (t) being independent of u (t)).
• the pump takes energy E j during systole:
• E o P (t) .v (t) dt.
• E Q - E j P (t) .v (t) dt.
• the pump then behaves essentially as an additional elastance (elasticity factor), adding to that, natural, of the artery according to the operating diagram exposed above and with the same benefit.
• the heart alone supplies the energy demand. This can for example apply to a patient at rest.
• - positive in this case, the cardiac assistance is pushed further, the substantial increase in the volume of blood stored by the pump and the correlative decrease in the systolic pressure make it possible to significantly increase the volume of systolic ejection by means of heart energy less than or equal to what it was before this increase.
• the pump provides during the diastole the additional energy necessary to compensate for the deficit of the heart.
• the pump makes it possible to dose the cardiac assistance, cycle to cycle, according to the hemodynamic demand.
• the dosage can in particular be carried out so as to charge the heart to the maximum of its operational capacities in all circumstances, or to a portion of these at the doctor's choice, by means of adjustments and automatisms such as discussed below.
• the major advantage of a proportional dosage of this type is to reduce the energy consumption of the device as much as possible.
• the state of the cardiovascular system is characterized by the data available to the device through sensors.
• the list of data is as follows:
• minute ventilation MV and / or posture and / or other parameters can still be taken into account from the corresponding appropriate sensors (eg from accelerometers for posture and activity G).
• the data are obtained as follows: - P (t): by a specific sensor placed in the pump on the blood side or on the hydraulic fluid side.
• P0 - 2V and P0 - ⁇ 2 A B y ⁇ es ca Pt ors specific arranged one 34 in the right heart (P0 2 y), or elsewhere in the veins, and the other 36 in the aortic flow through the pump (PC * 2A ).
• the useful parameter is P0 2-v "P0 2V .
• the use of P0 2V only is possible to operate the system, but with a reduction in performance.
• - F via the electrocardiogram (ECG) or directly from the occasional frequency synthesizer, if necessary.
• ECG electrocardiogram
• the ECG is picked up by a ventricular endocavity electrode 38 in the right heart. It determines the moment of right ventricular depolarization, from which we can deduce the moment of depolarization of the left ventricle, and the heart rate F.
• the ECG can be picked up by an epicardial electrode placed on the left ventricle.
• - dP / dt this parameter is the average slope of the pressure in the left ventricle during the isovolumetric contraction of the latter, slope obtained from the pressure difference and the duration between the start of depolarization and the opening of the aortic valve, detected by the corresponding discontinuity of P (t).
• the data are deduced from the measurements carried out according to the use for which they are intended: a) during the previous cardiac cycle for rapid monitoring or an estimate of the trend, or b) from the weighted moving average on a determined number of previous cycles, in order to smooth and / or allow the effects to stabilize.
• the aortic pressure P (t) is sampled at predetermined intervals.
• the data are variable depending on state parameters such as physical activity, gastrointestinal, cerebral, posture, the environment or resulting from coexisting pathologies, impregnation of drugs, etc. They are also to a certain extent interdependent. Expression of need for cardiac assistance
• the need for heart assist is determined from a en ⁇ seem data and reference data combinations. This set is established taking into account the cardiovascular pathology and introduced into the device by programming.
• the reference set has its own dynamics depending on the state parameters: for example, the expression of normality at high effort is translated by values of P (t), PO 2A -PO 2V , dP / dt different from those which express normality at rest. It is the same for normalities with or without pharmaceutical impregnation, etc.
• the reference set will finally be determined by the data with two variables: P (t, F), P0 2A (F) -P0 2V (F), F, dP / dt (F) and / or the combination of those data.
• the assistance methods are defined by programming according to the nature, amplitude and speed of variation of the deviations.
• a follow-up program is launched in addition to the previous one, including for example the strengthening of sampling, start-up, pursuit, termination algorithms, etc., and reacting on the assistance management according to the evolution of the disturbance which is the cause and the response of the organism.
• Cardiac assistance is determined by the displacement speeds of the piston u (t) during systole and v (t) during diastole, respectively homologous to the volumes ⁇ .u (t) accumulated and ⁇ .v (t ) restored by the pump and from the instant the origin of these functions with respect to the cardiac cycle, t ⁇ for u (t) and t R for v (t). Determination of u ( t) and t A :
• the artificial increase in the aortic volume ⁇ .u (t) causes, as explained above, an increase in the systolic flow which re ⁇ tentit on the energy delivered by the left ventricle and on the energy return of this one.
• the effects are as beneficial as those of the softening of the arteries. It is also important that u (t) and t A are properly adapted to heart function.
• a preferred form of the profile of u (t) can, for example, be an exponential decrease, by analogy with the elastic behavior of the arteries, while t A can control the start of systole in advance in order to reduce the systolic pressure.
• the profile of u (t) and t A are adjusted according to the patient by programming and do not vary according to his activity.
• the amplitude of u (t), and therefore j s u (t) dt, constitutes the essential action parameter of cardiac assistance with regard to the artificial increase in aortic volume or in other words, the decrease in the afterload of the left ventricle.
• the amplitude of u (t), in particular the quantity Lu (t) dt homologous to the total volume stored by the pump ⁇ .J s u (t) dt, is determined as a function of the desired cardiac output. Given the response time of the cardiovascular system to the impulse given to it, the amplitu ⁇ of u (t) can be incremented progressively, each increment being defined as a function of the result of the previous one within a determined period, and limited by the response capacity of the heart and the prosthesis. Determination of vft) and t ⁇ :
• v (t) and t R determine, from the blood pressure at the start of the diastole and in cooperation with the arterial compliance, the instantaneous blood pressure and arterial flow during the diastole. At equilibrium, the total arterial flow during diastole, added to the arterial flow during systole, is naturally equal to the flow of the left ventricle.
• the cardiac assistance can be carried out at different degrees of intensity according to the dosage of the reduction of the afterload and of the energy supply of the prosthesis.
• 0 Cardiac assistance can be either predetermined or automatic.
• the predetermined assistance is obtained by programming at the pos of u (t), t A , v (t), t R and of the algorithm for correcting u (t) and of the pro ⁇ thread v (t) as well. as of t R as a function of heart rate F.
• Automatic assistance is obtained by programming the reference set, algorithms for correcting this set as a function of state parameters, which will be reduced in practice at the heart rate F, thresholds for triggering the assistance and the intensity thereof. 0 Programming includes the following operations:
• the programmed device does the following:
• FIG. 3 illustrates the shape of the pressure wave, that is to say the function P (t), aortic pressure as a function of time.
• the aorta which has been dilated by the reinjection, begins to discharge approximately exponentially in the downstream arterial network.
• the diastolic pressure at the end of the diasole will be greater than this same pressure at the end of the previous diastole.
• the cycle will not be balanced, and it will only become so a few cycles later.
• the difference between the solid line curve and the dashed curve is representative of the differences in capillary flow with and without assistance.
• the balance sheet (difference between the areas delimited by the curves before and after the moment of reinjection) represents feel the contribution due to the enslavement of cardiac output.
• the exact gain in cardiac output can be determined after stabilization of the pressure profile, to take into account the fact that the activation of the assistance will modify a certain number of physiological variables such as diastolic and systolic pressures, filling of the ventricle left, energy of the left ventricle, resistance R (which decreases), frequency F (which decreases), etc. with in particular better irrigation of the coronaries. Stabilization at the new equilibrium state will therefore not be immediate.
• the cardiac output represented by the area delimited by the curve during the duration of the cycle, is delivered by the left ventricle during systole. That is, the area relative to the systole represents the capillary flow during the systole, while the cardiac output stored by the dilation of the artery during the systole is represented by the area relating to the diastole.
• the pressure profile thus immediately informs about the part of the systolic ejection which is stored in the artery - and in the variable volume of the pump if the latter is activated - and the part which is perfused directly into the downstream arterial network (or in the capillaries, at dilation near the downstream arteries).

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

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Citations (6)

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• 1996
  • 1996-02-21 FR FR9602135A patent/FR2744923B1/fr not_active Expired - Fee Related
• 1997
  • 1997-02-19 JP JP9529846A patent/JP2000504611A/ja not_active Ceased
  • 1997-02-19 EP EP97906219A patent/EP0959911B1/fr not_active Expired - Lifetime
  • 1997-02-19 WO PCT/FR1997/000302 patent/WO1997030739A1/fr not_active Ceased
  • 1997-02-19 DE DE69731848T patent/DE69731848T2/de not_active Expired - Lifetime
  • 1997-02-19 AT AT97906219T patent/ATE283716T1/de not_active IP Right Cessation
  • 1997-02-19 US US09/125,650 patent/US6050932A/en not_active Expired - Lifetime

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