Single cannula ventricular-assist method and apparatus

• US 6,511,413 B2
• Filed: 05/16/2001
• Issued: 01/28/2003
• Est. Priority Date: 05/16/2001
• Status: Expired due to Fees

• Current Assignee: Levram Medical Devices Limited
• Original Assignee: Levram Medical Devices Limited
• Inventors: Landesberg, Amir
• Primary Examiner(s): Evanisko, George R.
• Assistant Examiner(s): KHAN, OMAR A
• Application Number:
  US09/858,343
• Publication Number:
  US 20020173693A1
• Time in Patent Office: 622 Days
• Field of Search: 600/16-18, 623/3.28
• US Class Current: 600/17
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2210/125 Heart
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 2230/30 Blood pressure A61M2230/04 takes precedence
• 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 60/427 the force acting on the blood contacting member being hydraulic or pneumatic
• CPC Class Codes: A61M 60/441 generated by an electromotor
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• CPC Class Codes: A61M 60/523 using blood flow data, e.g. from blood flow transducers
• CPC Class Codes: A61M 60/531 using blood pressure data, e.g. from blood pressure sensors
• CPC Class Codes: A61M 60/546 of blood flow, e.g. by adapting rotor speed
• CPC Class Codes: A61M 60/869 Compliance chambers containing a gas or liquid other than blood to compensate volume variations of a blood chamber

Abstract

A system for assisting the failing ventricle, which utilizes a single blood displacement chamber and a single cannula. The cannula is inserted into the failing ventricle cavity and is connected to a blood displacement actuator. The device produces blood displacement at a critical time for a critical duration and with blood flow time course such that it improves the systolic function of the heart: augments the cardiac output and increases the generated pressure. The device also improves the diastolic function by increasing the ventricle compliance and imposing rapid relaxation of the ventricle wall. The device provides additional external work without deteriorating the mechanical function of the failing ventricular, moreover it decreases the energy consumption of the failing heart and improves the coronary perfusion. Consequently, the device improves the balance between the energy supply (coronary perfusion) to the ventricle wall and the mechanical demands, and allows recovery of the failing heart.

Claims

1. A ventricular assist method that comprises the steps of:

(a) inserting into at least one failing ventricular cavity of a failing heart through a wall thereof a respective cannula connected to a blood displacement chamber having a blood displacement actuator;

(b) in cadence with normal functioning of said failing heart, effecting blood inflow into the ventricle cavity from the displacement chamber, with each heart beat and commencing only after opening of an outlet valve of the respective ventricular cavity of the failing heart or only after detecting a shortening of a monitored region of a wall of the respective ventricular cavity of the failing heart and continuing during an ejection phase of the respective ventricular cavity, thereby augmenting ejection volume from the respective ventricular cavity by up to a maximum volume generated by the blood displacement actuator, per systolic phase;

(c) controlling a time course of blood inward displacement through the said cannula in step (b) thus reducing a shortening and thereby increasing a ventricle pressure in said ventricular cavity, but at the same time preventing stretching of a respective monitored ventricular wall region of the failing heart by comparison with ventricular wall shortening without an inflow from the chamber; and

(d) retracting blood from said failing ventricular cavity, through the cannula immediately upon closing of a respective outlet valve of the failing ventricular cavity.

2. The method defined in claim 1, further comprising the steps of:

measuring parameters of ventricular wall motion during systole, the parameters comprising one of regional wall motion parameters, and global cardiac function parameters; and

applying and controlling a profile of the blood inflow generated by the blood displacement actuator to decrease a measured ventricular wall motion, thereby obtaining an increase in pressure within the respective ventricular cavity and an increase in the cardiac output.

3. The method defined in claim 2 wherein said parameters include ventricular diameter.

4. The method defined in claim 2 wherein said global cardiac function parameters include ventricular volume.

5. The method defined in claim 2 wherein said regional wall motion parameters include ventricular wall strain.

6. The method defined in claim 2 wherein said global cardiac function parameters include ventricular flow.

7. The method defined in claim 2, further comprising inserting a respective cannula into each of the ventricles of the failing heart and connecting the respective cannula to a respective blood displacement chamber, blood flow in each of said cannulas being effected by respective actuators.

8. The method defined in claim 1, further comprising the steps of:

monitoring at least one parameter of ventricular wall shortening and at least one parameter of and ventricular output of said ventricular cavity during systole; and

in response to measurement of said parameters of ventricle wall shortening and cardiac output and selectively either in real time or by beat-by-beat computation, determining a desired blood volume and inflow time profile; and

controlling a rate and profile of blood inflow of the respective blood displacement actuator during step (b).

9. The method defined in claim 1, further comprising inserting said cannula into a failing ventricular cavity at the apex thereof or at another site of a respective wall affording access without interference with papillary muscle and ventricle valve apparatus or cardiac circulatory or conductive systems.