Optimized pulsatile-flow ventricular-assist device and total artificial heart

• US 6,632,169 B2
• Filed: 03/13/2001
• Issued: 10/14/2003
• Est. Priority Date: 03/13/2001
• Status: Expired due to Fees

• Current Assignee: LTK Enterprises LLC
• Original Assignee: LTK Enterprises LLC
• Inventors: Grandia, Lonn, Korakianitis, Theodosios
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US09/805,523
• Publication Number:
  US 20030032853A1
• Time in Patent Office: 945 Days
• Field of Search: 600/16-18, 128/898
• US Class Current: 600/16
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/178 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
• CPC Class Codes: A61M 60/183 drawing blood from both ventricles, e.g. bi-ventricular assist devices [BiVAD]
• CPC Class Codes: A61M 60/196 replacing the entire heart, e.g. total artificial hearts [TAH]
• CPC Class Codes: A61M 60/432 with diastole or systole switching by stopping or reversing the blood pump operating at a much higher cyclical speed than the heart beat
• CPC Class Codes: A61M 60/462 Electromagnetic force
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• CPC Class Codes: A61M 60/531 using blood pressure data, e.g. from blood pressure sensors
• CPC Class Codes: A61M 60/569 synchronous with the native heart beat
• CPC Class Codes: A61M 60/892 Active valves, i.e. actuated by an external force
• CPC Class Codes: A61M 60/894 Passive valves, i.e. valves actuated by the blood
• CPC Class Codes: A61M 60/896 having flexible or resilient parts, e.g. flap valves

Abstract

A method of optimizing a mechanical cardiac pumping device includes modeling the circulatory system of the patient who will receive the mechanical cardiac pumping device and identifying an operating condition of the native heart to which the device will respond. The model is used to determine the required blood volume to be ejected from the device and an initial estimate of the power required to be provided to the mechanical cardiac pumping device is provided in order to provide the required ejected blood volume. The resultant ejected blood volume is evaluated with data obtained from the model and the estimate of the power requirement is then updated. The above steps are iteratively performed until the power required to obtain the necessary ejected blood volume is identified. Possible variations of power and pumping rate that allow the mechanical cardiac pumping device to provide the required volume are determined and the variation that best matches the physiological constraints of the patient and minimizes the power required by the mechanical cardiac pumping device is selected. The steps are iteratively performed until the mechanical cardiac pumping device is optimized to respond to each desired operating condition of the native heart.

Claims

1. A method of optimizing a mechanical cardiac pumping device wherein unsteady fluid mechanics are used to optimize the forcing function imposed by the mechanical cardiac pumping device such that the power required by the mechanical cardiac pumping device is the minimum power required to complement the cardiac output of the diseased native heart, said method comprising the steps of:

a. modeling the dynamic response of the diseased native heart and of the mechanical cardiac pumping device with experimental data;

b. using the instantaneous non-linear mass, [M], damping, [C], and stiffness, [K] matrices of the dynamic model, and corresponding elemental displacements {x} and its derivatives {{umlaut over (x)}} and {{dot over (x)}}, as inputs into an equation which sums these matrices to calculate the forcing function, F{t}, of the dynamic system;

c. calculating the forcing function of the diseased native heart, F_nh{t};

d. calculating the required forcing function of the mechanical cardiac pumping device, F_vad{t};

e. inputing the value of F_vad{t} from step d, above, into a controller; and

f. connecting operatively the controller to a mechanical cardiac pumping device, such that the controller is able to direct to the mechanical cardiac pumping device the minimum power required to achieve F_vad{t}.

2. A method of optimizing a mechanical cardiac pumping device wherein unsteady fluid mechanics are used to optimize the forcing function imposed by the mechanical cardiac pumping device such that the power required by the mechanical cardiac pumping device is the minimum power required to complement the cardiac output of the diseased native heart, said method comprising the steps of:

a. modeling the dynamic response of the diseased native heart and of the mechanical cardiac pumping device with experimental data;

b. using the instantaneous non-linear mass, [M], damping, [C], and stiffness, [K] matrices of the dynamic model, and corresponding elemental displacements {x} and its derivatives {{umlaut over (x)}} and {{dot over (x)}}, as inputs into an equation of the form;

3. A method of optimizing a mechanical cardiac pumping device wherein unsteady fluid mechanics are used to optimize the forcing function imposed by the mechanical cardiac pumping device such that the power required by the mechanical cardiac pumping device is the minimum power required to complement the cardiac output of the diseased native heart, said method comprising the steps of:

a. modeling the dynamic response of the diseased native heart and of the mechanical cardiac pumping device with experimental data;

b. using the instantaneous non-linear mass, [M], damping, [C], and stiffness, [K] matrices of the dynamic model, and corresponding elemental displacements {x} and its derivatives {{umlaut over (x)}} and {{dot over (x)}}, as inputs into an equation of the form;