EP1129736A1
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EP
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Ventricular-assist method and apparatus
Assignee: Levram Medical Devices Ltd
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Filing: 2001-02-28
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Granted: —
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Expires: 2021-02-28
Abstract
Abstract A system for ventricular-assist of the normal heart action utilizes an intraventricular device (15) with a limited volume which is expanded at a critical time, for a critical duration and with a volume change course such that it assists the pumping action of the heart without inducing stretching of the ventricular wall (11).
Inventors
- 👤 Amir Landesberg
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 03:48
CPC Classifications
A; A61; A61M; A61M60/00; A61M60/10; A61M60/122; A61M60/165; A61M60/17; A61M60/40; A61M60/403; A61M60/408; A61M60/411; A61M60/178; A61M60/20; A61M60/295; A61M60/497; A61M60/50; A61M60/508; A61M60/515; A61M60/538; A61M60/126; A61M60/148; A61M60/247; A61M60/253; A61M60/268; A61M60/274; A61M60/424; A61M60/427; A61M60/432
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
203 words
A ventricular assist method which comprises the
steps of: (a) inserting into at least one failing ventricular
cavity of a failing heart through a wall thereof a respective
expandable intraventricular chamber having a maximum volume of 30
ml; (b) in cadence with normal functioning of said failing
heart, effecting expansion of said intraventricular 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 a detected 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 a maximum volume of the
intraventricular chamber per systolic phase; (c) controlling a course of expansion of each said
intraventricular chamber in step (b) to reduce a shortening and
at the same time to prevent stretching of a respective monitored
ventricular wall region of the failing heart by comparison with
ventricular wall shortening prior to insertion of the respective
intraventricular chamber; and (d) depressurizing and contracting each said
intraventricular chamber immediately upon closing of a respective
said outlet valve of the failing heart.
Claim 2
Dependent Claim
78 words
The method defined in claim 1, further comprising
the steps of: measuring parameters of ventricular wall motion during
systole and the expansion of a respective intraventricular
chamber in step (b) and parameters of global cardiac function;
and applying and controlling a profile of the expanding
intraventricular chamber in a course of expansion thereof to
decrease the measured ventricular wall motion thereby obtaining
an increase in pressure within the respective ventricular cavity
and an increase in the cardiac output.
Claim 3
Dependent Claim
95 words
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 ventricular output
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 shape of each said intraventricular chamber during
expansion thereof; and controlling the shape and a rate of expansion and a
rate of contraction of the respective intraventricular chamber
during step (b) to correspond to said desired shape.
Claim 4
Dependent Claim
12 words
The method defined in claim 3 wherein said
parameter is ventricular diameter.
Claim 5
Dependent Claim
12 words
The method defined in claim 3 wherein said
parameter is ventricular volume.
Claim 6
Dependent Claim
13 words
The method defined in claim 3 wherein said
parameter is ventricular wall strain.
Claim 7
Dependent Claim
12 words
The method defined in claim 3 wherein said
parameter is ventricular flow.
Claim 8
Dependent Claim
35 words
The method defined in claim 3 wherein each said
intraventricular chamber is a balloon and the expansion of each
said intraventricular chamber is effected by fluid expansion of
the respective balloon with a physiological solution.
Claim 9
Dependent Claim
46 words
The method defined in claim 8 wherein a said
balloon is implanted into the failing ventricle 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.
Claim 10
Dependent Claim
174 words
A ventricular assist apparatus comprising: an expandable intraventricular chamber insertable into
a ventricular cavity of a failing heart through a wall thereof
and having a maximum volume of 30 ml; means including a computer-controlled actuator
connected to said intraventricular chamber for effecting
expansion and contraction of said intraventricular chamber in
cadence with normal functioning of said failing heart and
commencing only after opening of an outlet valve of the
respective ventricular cavity of the failing heart or only after
a detected 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 of the
intraventricular chamber per systolic phase; and at least one sensor of wall shortening of said failing
ventricle connected to said computer-controlled actuator for
controlling a course of expansion of said intraventricular
chamber to decrease ventricular wall shortening by comparison to
wall shortening without expansion of said intraventricular
chamber.
Claim 11
Dependent Claim
51 words
The apparatus defined in claim 9 wherein said
means including said computer-controlled actuator includes means
for monitoring parameters of ventricle wall shortening and
cardiac output, and means for correcting an expansion function of
said intraventricular chamber based upon a difference between
desired and evaluated cardiac output using a feedback
amplification factor.
Claim 12
Dependent Claim
193 words
The apparatus defined in claim 10, further
comprising a computer receiving input from said sensor and
controlling said actuator with an output, said computer being
programmed for each heartbeat ( n ) to: (a) evaluate cardiac output and work at the n beat; (b) compare the evaluated cardiac output and work at
the n beat with a desired cardiac output to determine an
amplification factor (A F ) constituting a gain of a feedback loop
which determines a rate at which a function of intraventricular
chamber expansion will be corrected to achieve a desired cardiac
output; (c) multiplying the amplification factor (A F ) by a
weighting function (W(t)) to enable an operator to determine a
magnitude of feedback; (d) evaluate ventricle wall shortening (S n (t)) and
compare the evaluated wall shortening with a desired wall
shortening (Des(t)) to obtain an incremental correction profile Err n (t)=Des(t)-S n (t) ; (d) generate an expansion function EXP n+1 (t)=EXP n (t)+A F *W(t)*Err n (t); and (e) control expansion of the intraventricular chamber
at a next beat (n+ 1 ) with said expansion function EXP n+1 (t)=EXP n (t)+A F *W(t)*Err n (t)
Claim 13
Dependent Claim
59 words
The apparatus defined in claim 12 wherein said
computer is an implanted computer which controls the
intraventricular chamber at the next beat (n+1) with an
expansion/contraction function by regulating onset time of
expansion/contraction and a function of expansion, the
expansion/contraction function being calculated between
heartbeats before an onset of a next beat, the onset time-being
detected in real time.
Claim 14
Dependent Claim
40 words
The apparatus defined in claim 12 wherein said
weighting factor (W(t)) is a function of time determined by said
operator where O≤W (t) ≤1 when 0≤t≤T, and t=o is the onset of
expansion and t=T is the end of expansion.
Claim 15
Dependent Claim
186 words
The apparatus defined in claim 10, further
comprising a computer receiving input from said sensor and
controlling said actuator with an output, said computer being
programmed for each heartbeat ( n ) to: (a) evaluate cardiac output and work at the n beat; (b) compare the evaluated cardiac output and work at
the n beat with a desired cardiac output and determine an
amplification factor that will not cause wall stretch in part
based upon additional inputs; (c) evaluate ventricle wall shortening (S n (t)) at said
n beat and providing the ventricle wall shortening as one of said
additional inputs; (d) detect possible ventricle wall lengthening from the .
evaluation of the wall shortening in step (c) and providing
therewith another of said additional inputs, and triggering an
alarm upon ventricular wall lengthening (f) from the amplification factor and a desired profile
of expansion, determine a time course of expansion of the
intraventricular chamber; and (g) generate an expansion function representing the
time course of expansion control expansion of the
intraventricular chamber at a next beat ( n + 1 ) with said expansion
function.
Claim 16
Dependent Claim
36 words
The apparatus defined in claim 10 wherein said
computer is programmed to initiate expansion of said
intraventricular chamber upon detection of an outlet valve
opening or significant shortening of the monitored ventricle wall
in real time.
Claim 17
Dependent Claim
28 words
The apparatus defined in claim 10 wherein said
computer is programmed to initiate contraction of said
intraventricular chamber upon detection of an outlet valve
closure in real time.
Claim 18
Dependent Claim
38 words
The apparatus defined in claim 17 wherein said
computer is programmed to connect said intraventricular chamber
to intrathoracic pressure and said actuator including a
compressible extraventicular chamber and connection tubing
between said extraventricular chamber and said intraventricular
chamber.
Claim 19
Dependent Claim
76 words
The apparatus defined in claim 10, further
comprising means for detecting opening and closure of said outlet
valve and including at least one of the following: means for measuring intraventricular and aortic
pressure or a gradient between intraventricular and aortic
pressure; a Doppler or an ultrasonic or electromagnetic flowmeter
measuring ventricle outlet flow; ultrasound or electrical impedance means for measuring
intraventricular volume; strain gauge means for measuring ventricle wall
shortening; and means for detecting heart sounds.
Claim 20
Dependent Claim
75 words
The apparatus defined in claim 10, further
comprising means for monitoring timing and profile of
intraventricular chamber expansion based on regional ventricle
wall motion, to optimize the apparatus based on a preserved
functional region of the ventricle wall, said means for
monitoring including at least one of the following: means for measuring ventricle diameters or distances
between anatomical points on the ventricle wall; and means for measuring local changes in strain in the
ventricle wall.
Claim 21
Dependent Claim
31 words
The apparatus defined in claim 10 wherein said
actuator is selected from the group which consists of a syringe
pump, a bellows or a flexible membrane operated by an actuator
motor.
Claim 22
Dependent Claim
30 words
The apparatus defined in claim 21 wherein said
actuator motor is selected from the group which consists of an
electric motor, a transplanted heart and a patient's own skeletal
muscle.
Claim 23
Dependent Claim
23 words
The apparatus defined in claim 9 wherein said
sensor includes at least one sonomicrometer on said ventricle
wall or on the intraventricular chamber.
Claim 24
Dependent Claim
33 words
The apparatus defined in claim 22, further
comprising at least one sensor on said intraventricular chamber
for measuring a volume thereof and an additional sensor on said
intraventricular chamber for measuring ventricle pressure.
References Cited (Backward Citations)
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