Patent EP0836834A2 successfully refreshed from Google Patents.
EP0836834A2
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EP
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Non-synchronous laser-assisted myocardial revascularization
Assignee: Artivion Inc
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Filing: 1997-10-15
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Granted: —
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Expires: 2017-10-15
Abstract
Abstract A method of selecting laser parameters for performing laser-assisted myocardial revascularization to avoid inducing undesired cardiac arrhythmia without synchronization of delivery of laser energy and the patient's cardiac cycle, the method comprising the steps of minimizing the power level of laser energy used, thereby decreasing the overall trauma to the heart, selecting a pulse frequency as great as possible while avoiding adverse summation effects, selecting a pulse width as wide as possible to prevent excessively high peak powers per pulse and not so wide as to cause undesired thermal damage, selecting an energy flux rate, shaping the front end of each pulse of laser energy to provide efficient, non-explosive TMR channeling, and correcting the selected power level, pulse width, pulse frequency and energy flux rate for mechanical events, including method of access to the heart, position of selected portions of myocardium in the heart, temporal duration of the procedure, natural movement of the heart, specific heart geometry, pre-existing heart arrhythmia and other factors causing a predisposition to heart arrhythmia. A method for performing laser-assisted transmyocardial revascularization (TMR) and percutaneous transluminal myocardial revascularization (PTMR) using such laser energy with parameters selected to avoid inducing undesired cardiac arrhythmia, the method comprising the steps of generating laser energy having a predetermined non-square wave shape, a predetermined wavelength, a predetermined energy flux and a predetermined power level, and delivering the laser energy in a plurality of pulses, the plurality of pulses having a predetermined pulse frequency and a predetermined pulse width, to selected portions of myocardium to form TMR and PTMR channels without synchronizing delivery of the laser beam with the cardiac cycle.
Inventors
- 👤 Douglas Murphy-Chutorian
- 👤 Richard L. Mueller
- 👤 Mark Roush
- 👤 Stuart D. Harman
- 👤 Jeffrey J. Giba
- 👤 Fred G. Kinley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 15:02
CPC Classifications
A; A61; A61B; A61B18/00; A61B18/18; A61B18/20; A61B18/22; A61B18/24; A61B17/00; A61B17/00234; A61B2017/00238; A61B2017/00243; A61B2017/00247; A61B2017/00681; A61B2017/00694; A61B2017/00703; A61B2018/00315; A61B2018/00345; A61B2018/00351; A61B2018/00392
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
133 words
A method of setting up an apparatus for
performing transmyocardial revascularization (TMR) or
percutaneous transluminal myocardial revascularization
(PTMR) with laser energy having parameters selected to
avoid cardiac arrhythmia, the method comprising the
following steps, in combination: determining a wavelength of the laser energy from a
laser selected to perform transmyocardial
revascularization; using the wavelength determination to select
parameters for the laser energy to produce a non-square
wave shape; and generating the laser energy at the determined
wavelength with the selected parameters to produce the
non-square wave shape; whereby the apparatus is adapted
to deliver the generated laser energy in one or more
pulses to selected portions of heart tissue to perform
transmyocardial revascularization or PTMR in myocardium
without inducing cardiac arrhythmia and without
synchronizing delivery of the laser energy to a cardiac
cycle.
Claim 2
Dependent Claim
19 words
The method of Claim 1 wherein the selected
parameters are power level, energy flux, pulse width, and
pulse frequency.
Claim 3
Dependent Claim
83 words
The method of Claim 2 wherein the laser energy
has a wavelength of between about 1.8 and about 2.2
microns, an energy flux of about 1.78 J/square millimeter
and a power level of at least about 6 watts, the laser
energy being delivered with a pulse frequency of at least
about 5 Hertz and a pulse width of between about 150 and
about 350 millisecond, the laser energy as delivered
causing about 5 millimeters or less lateral necrosis
surrounding a transmyocardial treatment site.
Claim 4
Dependent Claim
15 words
The method of Claim 3 wherein the laser energy
is generated by a Holmium:YAG laser.
Claim 5
Dependent Claim
77 words
The method of Claim 2 wherein the laser energy
has a wavelength of about 0.308 microns, a power level
of about 2 watts and an energy flux of between about 2
and about 8 J/square millimeter, and is delivered with a
pulse frequency of between about 5 and about 25 Hertz and
a pulse width of about between about 10 and about 200
microseconds, and causes about 5 microns lateral necrosis
surrounding the TMR channel produced thereby.
Claim 6
Dependent Claim
16 words
The method of Claim 5 wherein the laser energy
is generated by a Xe:Cl excimer laser.
Claim 7
Dependent Claim
64 words
The method of. Claim 2 wherein the laser energy
has a wavelength of about 10.6 microns, an energy flux of
about 51 J/square millimeter and a power level at least
about 800 watts, is delivered in a single pulse about of
0.03 seconds and can be gated, and causes between about
0.05 to about 0.2 millimeters lateral necrosis
surrounding a TMR channel produced thereby.
Claim 8
Dependent Claim
16 words
The method of claim 7 wherein the laser energy
is generated by a CO 2 laser.
Claim 9
Dependent Claim
64 words
The method of Claim 2 wherein the laser energy
has a wavelength of between about 0.488 and about 0.514
microns, an energy flux of between about 1.3 and about
12.74 J/square millimeter and a power level at least
between about 1 and about 10 watts, is delivered in a
single pulse, and causes approximately 4 millimeters
lateral necrosis surrounding a TMR channel produced
thereby.
Claim 10
Dependent Claim
15 words
The method of Claim 9 wherein the laser energy
is generated by an Argon laser.
Claim 11
Dependent Claim
78 words
The method of Claim 2 wherein the laser energy
has a wavelength of about 1.06 microns, an energy flux of
between about 9.5 and about 13 J/square centimeter and a
power level at least between about 2 and about 100 watts,
is delivered with a pulse frequency of between about 1
and about 10 Hertz and a pulse width of about 10
nanoseconds, and causes at least about 15 millimeters
lateral necrosis surrounding a TMR channel produced
thereby.
Claim 12
Dependent Claim
15 words
The method of Claim 11 wherein the laser energy
is generated by an Nd:YAG laser.
Claim 13
Dependent Claim
67 words
The method of Claim 2 wherein the laser energy
has a wavelength of about 2.94 microns, an energy flux of
between about 50 and about 500 J/square millimeter, is
delivered with a pulse frequency of between about 1 and
about 15 Hertz and a pulse width of between about 1 and
about 250 microseconds, and causes about 0.1 millimeters
lateral necrosis surrounding a TMR channel produced
thereby.
Claim 14
Dependent Claim
15 words
The method of Claim 13 wherein the laser energy
is generated by an Er:YAG laser.
Claim 15
Independent Claim
26 words
An apparatus for performing transmyocardial
revascularization (TMR) or percutaneous transluminal
myocardial revascularization (PTMR) as set up by the
method of any one of the preceding claims.
Claim 16
Dependent Claim
14 words
An apparatus according to claim 15 comprising a
catheter apparatus and laser delivery means.
Claim 17
Independent Claim
96 words
An apparatus for percutaneous transluminal
myocardial revascularization of a patient's myocardium
for relieving angina and avoiding cardiac arrhythmia, the
apparatus comprising a guidable elongated flexible lasing apparatus
encompassing an optical fiber and insertable into a
patient's vasculature, the distal end of the lasing
apparatus being guidable to an area within the patient's
heart, and directable to an area within the heart to be
revascularized; and a Holmium:YAG laser source operating at around 5
Hz with a laser pulse width between 100-250 milliseconds,
and approximately 0.7-0.9 Joules/mm 2 emitted from the
distal end of the lasing apparatus.
Claim 18
Dependent Claim
28 words
The apparatus of claim 17 wherein the lasing
apparatus includes an optical fiber that is between 600-1100
microns in diameter and the average laser power is
3.5 watts.
Claim 19
Independent Claim
114 words
An apparatus for percutaneous transluminal
myocardial revascularization of a patient for relief from
angina while avoiding cardiac arrhythmia during the
procedure, the apparatus comprising: a guidable elongated flexible lasing apparatus
encompassing an optical fiber insertable into the
patient's vasculature, the optical fiber having a
diameter between 600 and 1100 microns, the distal end of the lasing apparatus being
guidable to an area within the patient's heart, and
directable to an area within the heart to be
revascularised; and a Holmium:YAG laser source arranged to provide a
single pulse of laser energy with a laser pulse width
between 100-250 milliseconds and approximately 1.8
Joules/mm 2 emitted from the optical fiber's end of the
lasing apparatus.
Claim 20
Independent Claim
142 words
An apparatus for percutaneous transluminal
myocardial revascularization of a patient's heart for
relieving angina and avoiding cardiac arrhythmia, the
apparatus comprising a) a guidable elongated flexible lasing apparatus
encompassing an optical fiber with a distal end and
insertable into a patient's vasculature, the distal end
of the lasing apparatus being guidable to an area within
the patient's heart, and directable at an area within the
heart to be revascularised; b) means for controlling a distance the lasing
apparatus may be advanced into heart tissue; c) a Holmium:YAG laser source operating at around 5
Hz with a laser pulse width between 100-250 milliseconds; d) means for selecting a laser power level emitted
from the distal end dependent upon a controlled distance
of the distal end of the laser apparatus; e) means for selecting a number of laser pulses
based upon the controlled distance.
Claim 21
Dependent Claim
33 words
An apparatus according to claim 20 wherein the
apparatus further includes an ultrasound device for
determining a position of the distal end with respect to
a ventricle wall prior to each laser pulse.
Claim 22
Independent Claim
162 words
An apparatus for percutaneous transluminal
myocardial revascularization of a patient's heart for
relieving angina and avoiding cardiac arrhythmia, the
apparatus comprising: a) a guidable elongated flexible lasing apparatus
encompassing an optical fiber with optical distal end and
insertable into the patient's vasculature,the distal end
of the lasing apparatus being guidable to an area within
the patient's heart, and the distal end of the lasing
apparatus being directable to an area within the heart to
be revascularized; b) means for controlling a distance the distal end
may be advanced into heart tissue; c) an excimer laser source operating at around 15 Hz
with a laser pulse width where the distal end can emit
radiation of at least about 50 mJ/mm 2 , d) means for selecting a laser power level emitted
from the distal end of the lasing apparatus dependent
upon a controlled distance of the laser apparatus; and e) means for selecting a number of laser pulses
based upon the controlled distance.
Claim 23
Independent Claim
150 words
A method of selecting laser parameters for
performing laser-assisted percutaneous transluminal
revascularization (PTMR) to avoid cardiac arrhythmia and
without synchronization of delivery of laser energy to a
patient's cardiac cycle, the method comprising the
following steps, in combination: selecting a minimum power level of laser energy to
be used, the minimum power level being sufficient to
ablate heart tissue; setting a pulse frequency as great as possible and
selected to avoid summation effects; setting a pulse width as long as possible and
selected to prevent excessively high peak power without
causing undesired levels of thermal damage during PTMR; shaping a front end of each pulse of laser energy to
provide non-linear pulses to avoid cardiac arrhythmia
during PTMR; and correcting the selected power level, pulse width,
pulse frequency, and shaping for limiting the depth of a
formed channel to no more than half the wall thickness of
a patient's myocardium.
References Cited (Backward Citations)
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