U.S. patent application number 10/001360 was filed with the patent office on 2003-04-24 for cryoablation catheter for long lesion ablations.
Invention is credited to Heiner, Wilfred Peter, Korteling, Bart-Jan.
Application Number | 20030078570 10/001360 |
Document ID | / |
Family ID | 21695645 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030078570 |
Kind Code |
A1 |
Heiner, Wilfred Peter ; et
al. |
April 24, 2003 |
CRYOABLATION CATHETER FOR LONG LESION ABLATIONS
Abstract
The present invention relates to a cryoablation catheter,
comprising an outer tubular body with a closed distal end to form a
fluid cooling chamber and an inner tubular member having a proximal
end adapted to receive fluid suitable for cryoablation and a distal
end coupled to a fluid expansion nozzle wherein the inner tubular
member is movable in an axial direction to thereby change the
position of the nozzle within the fluid cooling chamber.
Inventors: |
Heiner, Wilfred Peter;
(Bakkeveen, NL) ; Korteling, Bart-Jan; (Mission
Viejo, CA) |
Correspondence
Address: |
AUDLEY A. CIAMPORCERO JR.
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
21695645 |
Appl. No.: |
10/001360 |
Filed: |
October 23, 2001 |
Current U.S.
Class: |
606/21 ;
606/23 |
Current CPC
Class: |
A61B 18/02 20130101;
A61B 2018/0262 20130101; A61B 2018/0212 20130101; A61B 2018/00196
20130101 |
Class at
Publication: |
606/21 ;
606/23 |
International
Class: |
A61B 018/02 |
Claims
That which is claimed is:
1. A cryoablation catheter system for creating linear lesions
comprising: an outer tubular member having a proximal end and a
distal end and being capable of insertion into the vessels of the
body; a sealing cap disposed at the distal end of the outer tubular
member for forming a cooling chamber at the distal end of the outer
tubular member; an inner tubular member slidably disposed within
the outer tubular member and having a proximal end and a distal
end, the proximal end of the inner tubular member being adapted to
receive a fluid which cools when expanded; a fluid expansion nozzle
disposed on the distal end of the inner tubular member; and, a
nozzle control system comprising an inner ring member formed of a
magnetic material fixedly mounted on the proximal end of the inner
tubular member, and an outer ring member formed of a magnetic
material slidably mounted on the outer tubular member which when
moved along the outer tubular member causes the inner magnetic ring
member to be pulled along with the outer magnetic ring member to
thereby cause the inner tubular member to be moved longitudinally
thereby causing the fluid expansion nozzle to be moved
longitudinally within the cooling chamber.
2. A cryoablation catheter system as defined in claim 1, wherein
the inner tubular member is disposed coaxially within the outer
tubular member so as to define a passageway between the inner
tubular member and the outer tubular member; and, a cylindrical
support member is disposed between the inner tubular member and the
outer tubular member, said support member having at least one
passageway which extends through the support member to permit fluid
to be returned through the passageway for removal from the catheter
system.
3. A cryoablation catheter system as defined in claim 2, wherein
the inner magnetic ring member is disposed coaxially within the
outer tubular member and extends in the passageway between the
inner tubular member and the outer tubular member; and, Said inner
magnetic ring member has at least one passageway which extends
through the inner magnetic ring member to permit fluid to be
returned through the passageway for removal from the catheter
system.
4. A cryoablation catheter system comprising a cryoablation
catheter including: an outer tubular member having a proximal end
and a distal end and being capable of insertion into the vessels of
the body; a sealing cap disposed at the distal end of the outer
tubular member for forming a cooling chamber at the distal end of
the catheter; an inner tubular member slidably disposed within the
outer tubular member and having a proximal end and a distal end; a
Joule-Thompson nozzle disposed on the distal end of the inner
tubular member; a nozzle control system comprising an inner ring
member formed of a magnetic material fixedly mounted on the
proximal end of the inner tubular member, and an outer ring member
formed of a magnetic material slidably mounted on the outer tubular
member which when moved along the outer tubular member causes the
inner magnetic ring member to be pulled along with the outer
magnetic ring member to thereby cause the inner tubular member to
be moved longitudinally thereby causing the Joule-Thompson nozzle
to be moved longitudinally within the cooling chamber; a source of
a high pressure gas coupled to the proximal end of the inner
tubular member; and, a control valve for varying the pressure of a
high pressure gas for varying the flow of gas to the Joule-Thompson
nozzle.
5. A cryoablation catheter system as defined in claim 4, wherein
the inner tubular member is disposed coaxially within the outer
tubular member so as to define a passageway between the inner
tubular member and the outer tubular member; and, a cylindrical
support member is disposed between the inner tubular member and the
outer tubular member, said support member having at least one
passageway which extends through the support member to permit fluid
to be returned through the passageway for removal from the
catheter.
6. A cryoablation catheter system as defined in claim 5, wherein
the inner magnetic ring member is disposed coaxially within the
outer tubular member and extends in the passageway between the
inner tubular member and the outer tubular member; and, said inner
magnetic ring member has at least one passageway which extends
through the inner ring magnetic member to permit fluid to be
returned through the passageway for removal from the catheter.
7. A cryoablation catheter system comprising: an outer tubular
member having a proximal end and a distal end and being capable of
insertion into the vessels of the body; a sealing cap disposed at
the distal end of the outer tubular member for forming a cooling
chamber at the distal end of the outer tubular member; an inner
tubular member slidably disposed within the outer tubular member
and having a proximal end and a distal end, the proximal end of the
inner tubular member being adapted to receive a fluid which when
expanded cools to an extremely low temperature; a Joule-Thompson
nozzle disposed on the distal end of the inner tubular member; and,
a nozzle control system comprising an inner ring member formed of a
magnetic material fixedly mounted on the proximal end of the inner
tubular member, and an outer ring member formed of a magnetic
material slidably mounted on the outer tubular member which when
moved along the outer tubular member causes the inner magnetic ring
member to be pulled along with the outer magnetic ring member to
thereby cause the inner tubular member to be moved longitudinally
thereby causing the Joule-Thompson nozzle to be moved
longitudinally within the cooling chamber.
8. A cryoablation catheter system as defined in claim 7, wherein
the inner tubular member is disposed coaxially within the outer
tubular member so as to define a passageway between the inner
tubular member and the outer tubular member; and, a cylindrical
support member is disposed between the inner tubular member and the
outer tubular member, said support member having at least one
passageway which extends through the support member to permit fluid
to be returned through the passageway for removal from the catheter
system.
9. A cryoablation catheter system as defined in claim 8, wherein
the inner magnetic ring member is disposed coaxially within the
outer tubular member and extends in the passageway between the
inner tubular member and the outer tubular member; and, said inner
magnetic ring member has at least one passageway which extends
through the inner ring member to permit fluid to be returned
through the passageway for removal from the catheter system.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a cryoablation catheter,
and more particularly to a cryoablation catheter for creating long
lesions.
[0003] 2. Description of the Prior Art
[0004] Many medical procedures are performed using minimally
invasive surgical techniques wherein one or more slender implements
are inserted through one or more small incisions into a patient's
body. With respect to ablation, the surgical implement may include
a rigid or flexible structure having an ablation device at or near
its distal end that is placed adjacent to the tissue to be ablated.
Radio frequency energy, microwave energy, laser energy, extreme
heat, and extreme cold may be provided by the ablation device to
destroy the tissue.
[0005] With respect to cardiac procedures, cardiac arrhythmia may
be treated through selective ablation of cardiac tissue to
eliminate the source of the arrhythmia. A popular minimally
invasive procedure, radio frequency (RF) catheter ablation,
includes a preliminary step of conventional mapping followed by the
creation of one or more ablated regions (lesions) in the cardiac
tissue using RF energy. Multiple lesions are frequently required.
Often, five lesions, and sometimes as many as twenty lesions may be
required before a successful result is attained. Sometimes only one
of the lesions is actually effective.
[0006] Deficiencies of radio frequency ablation devices and
techniques have been to some extent overcome by cryogenic mapping
and ablation. Such cryogenic mapping techniques are in U.S. Pat.
Nos. 5,423,807; 5,281,213 and 5,281,215. However, even though
combined cryogenic mapping and ablation devices often times permit
greater certainty and less tissue damage than RF devices and
techniques, both cryogenic and RF ablation devices are usually
configured for spot or circular tissue ablation.
[0007] Spot tissue ablation is acceptable for certain procedures.
However, other procedures may be more therapeutically effective if
multiple spot lesions are made along a predetermined line, or a
single elongate or linear lesion is created in a single ablative
step. Radio frequency ablation devices are known to be able to
create linear lesions by dragging the ablation tip along a line
while the ablation electrode is energized. U.S. patent application
Ser. No. 09/518,044 entitled, "Cryoablation Catheter For Long
Lesion Ablations," assigned to the same assignee as the present
invention disclosing the concept of "dragging" the ablation tip, or
the cooling tip, of a cryoablation catheter along a line in order
to create a long lesion. In order to accomplish this function, the
cryogenic cooling nozzle is moved longitudinally along the inside
of a cooling chamber to thereby cause the outer surface of the
cooling chamber to be cooled along a linear path which in turn
creates a linear lesion along the path.
SUMMARY OF THE INVENTION
[0008] In accordance with one aspect of the present invention there
is provided a cryoablation catheter system for creating linear
lesions which includes an outer tubular member capable of insertion
into the vessels of the body, a ceiling cap disposed at the distal
end of the outer tubular member for forming a cooling chamber at
the distal end of the tubular member, an inner tubular member
slidably disposed within the outer tubular member. The proximal end
of the inner tubular member is adapted to receive a fluid, such as
nitrous oxide. A fluid expansion nozzle, such as a Joule-Thompson
nozzle, is disposed on the distal end of the inner tubular member.
The catheter system also includes a nozzle control system which is
comprised of an inner ring member formed of a magnetic material
which is mounted on the proximal end of the inner tubular member,
and an outer ring member formed of magnetic material which is
slidably mounted on the outer tubular member. Because of the
magnetic attraction between these two magnetic members, when the
outer ring member is moved along the outer tubular member it
"pulls" or draws the inner magnetic ring member along with the
outer magnetic ring member to thereby cause the inner tubular
member to be moved longitudinally which in turn causes the fluid
expansion nozzle to be moved longitudinally within the cooling
chamber.
[0009] In accordance with another aspect of the present invention,
the inner tubular member is disposed coaxially within the outer
tubular member so as to define a passageway between the inner
tubular member and the outer tubular member, and a cylindrical
support member is disposed between the inner tubular member and the
outer tubular member for supporting the inner tubular member for
movement within the cooling chamber. The cylindrical support member
includes at least one passageway which extends through the support
member to permit fluid, such as, nitrous oxide, to be returned
through the passageway for removal from the catheter system. In
accordance with still another aspect of the present invention, the
inner magnetic ring member is disposed coaxially within the outer
tubular member and extends in the passageway between the inner
tubular member and the outer tubular member, and includes at least
one passageway which extends through the inner magnetic ring member
to permit fluid to be returned through the passageway for removal
from the catheter. In accordance with still another aspect of the
present invention, the fluid expansion nozzle takes the form of a
Joule-Thompson nozzle which is disposed on the distal end of the
inner tubular member.
[0010] With the nozzle control system of the present invention, it
is possible to provide a cryoablation catheter system for creating
linear lesions by moving the fluid expansion nozzle in a
longitudinal direction along the interior of the cooling chamber
while maintaining an entirely sealed catheter system. In other
words, by use of magnetic attraction which exists from an external
ring magnet and an internal ring magnet it is possible to "pull"
the fluid expansion nozzle along a longitudinal path within the
sealed cooling chamber while maintaining a hermetically sealed
catheter system.
[0011] These and other objects of the present invention will become
more apparent when considered in view of the following description
of a preferred embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Further properties, advantages and measures according to the
present invention will be explained in greater detail in the
description of a preferred embodiment, with reference to the
attached figures in which:
[0013] FIG. 1 is a schematic view of a system for cryoablation with
a catheter according to the present invention placed within a human
heart;
[0014] FIG. 2 illustrates in detail the distal tip of the
cryoablation catheter according to the present invention placed
within a human heart;
[0015] FIG. 3 illustrates in detail the proximal end of the
cryoablation catheter, the control handle and the coolant system
including the cooling nozzle control system in more detail; and
[0016] FIG. 3A illustrates in more detail a cross sectional view of
the cooling nozzle control system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] In FIG. 1 a cryoablation catheter system 1 according to the
present invention has been illustrated with a catheter 2. The
catheter 2 comprises an outer body 3, an inner body 6, a handle 4
and a deflection knob 5. The deflection knob 5 is connected with
the inner body 6 and the handle 4 with the outer body 3, whereby
the deflection knob 5 is movable in the axial direction of the
catheter 2 in relation to the handle 4 in such a way that the
distal tip of the inner body 6, where the inner body 6 opens out
into the lumen of the outer body 3, is movable in an axial
direction with respect to the distal tip of the catheter 2.
[0018] The deflection knob 5 is connected via a heat exchanger 25,
a connecting tube 27 through a control unit 24 and a valve 8 with a
gas cylinder 7, containing N.sub.2O. By way of an alternative, or
as an addition, also other substances than N.sub.2O may be used.
Preferably, a fluid is used of which the cooling effect only occurs
on expansion when it is ejected via the inner body 6 close to the
distal end of the catheter 2 into the lumen of the outer body 3.
This fluid will expand, as a result of which the cooling effect
will be achieved. N.sub.2O meets this requirement with satisfactory
results.
[0019] As illustrated in FIG. 1 the valve 8 constitutes the control
means with which the flow of N.sub.2O through the inner body 6, and
the pressure inside this inner body 6 is regulated. The pressure
depends on the intended effect of the cryoablation at the distal
tip of the catheter 2. In an embodiment of the present invention
not illustrated here, the catheter 2 has been provided near to the
distal end with measuring equipment, such as a thermocouple, which
also forms part of the control means, in which case the valve 8 is
activated on the basis of the measuring results obtained at the
thermocouple. In that case the measurement of the temperature is
set to a target value established in advance, in order to effect
the required degree of cryoablation.
[0020] The tip at the distal end of the catheter 2 may also be
provided with other measurement equipment to determine the position
of the nozzle 12 for instance. Examples of such measuring equipment
are marking rings which are recognizable when using imaging
techniques like MRI or when using x-ray radiation. Equipment to
determine whether the surrounding tissue also needs to be ablated
may be included here as well.
[0021] In the situation illustrated in FIG. 1, the distal end of
the catheter 2 has been introduced into a chamber of the heart 10
and advanced to a position where tissue 14 is located which is
suitable for ablation. It could however also concern here
applications in a vein or at any other location. The only thing
which is important, is that in the body cavity there is tissue,
like the tissue 14 illustrated here, which qualifies for
ablation.
[0022] FIG. 2 is a detailed and partly cross-sectional view of the
distal end of the catheter 2 in a position for use. The inner body
6 opens out into the internal lumen 16 of the outer body 3 close to
the distal end of the catheter. Through the inner body 6 a flow of
N.sub.2O coolant is supplied, which is ejected via a nozzle 12,
which preferably takes the form of a Joule-Thompson nozzle, so that
a cold zone 13 is created. In the immediate proximity of this cold
zone 13, at the nozzle 12 of the inner body 6, the coldness created
on the outside of the outer body 3 is such that ice 15 is formed
and the tissue 14 is ablated.
[0023] As has been described in connection with FIG. 1, the
deflection knob 5, which is connected with the inner body 6, is
movable in relation to the handle 4, which is connected with the
outer body 3. In this manner the nozzle 12 at the distal end of the
inner body 6 is moved in relation to the outer body 3. In the
situation illustrated here, the outer body 3 on the other hand has
in the meantime become stuck in the ice 15, and is consequently no
longer movable. The inner body 6 and, in particular in the
proximity of the nozzle 12 hereof, a sliding block 11 has been
arranged around the inner body 6 close to the nozzle 12, which
functions as a distancing body. The dimensions of the sliding block
11 correspond to those of the internal lumen 16 of the outer body
3, so that it can move freely up and down in the outer body 3 in
the direction indicated by arrow "A," in which changes can be made
in the position of the nozzle 20 12. The sliding block 11 also
includes passageways 11a which extend through the sliding block.
The sliding block 11 is provided with the passageways 11a to allow
the coolant fluid to flow back from the cooling chamber.
[0024] All components of the catheter illustrated here have
preferably been made of materials which do not shrink together due
to expansion or contraction of the materials.
[0025] In the embodiment illustrated here, the outer body 3 has
been closed off by means of a closure 17.
[0026] The catheter system illustrated in FIG. 3 includes a
catheter 2. The proximal end of the catheter 2 carries a handle 4,
with which the catheter has been received in the deflection knob 5.
A pressure line 23 extends from the proximal end of the catheter 2
to the distal end. The pressure line 23 supplies high pressure
refrigerant to the distal end of the catheter.
[0027] FIGS. 3 and 3A also illustrate in more detail the nozzle
positioning mechanism 5a which is comprised of an outer ring 40
formed of a magnetic material which is slidably mounted on a
cylindrical piston 42. The outer magnetic ring is hermetically
sealed within a polymer layer 44. An inner ring 46 extends around
and is fixedly attached to the inner body 6. The inner ring 46 is
also formed of a magnetic material. In addition, the inner magnetic
ring includes multiple passageways 47 which serve to permit the
cooled fluid to be removed from the catheter system 2. As
previously described, the cooling nozzle 12 is mounted on the
distal end of the inner body 6. Accordingly, as the outer magnetic
ring 40 is moved along the cylindrical piston 42, it causes the
inner magnetic ring 46 to be pulled along through magnetic
attraction. As the inner ring 46 is pulled along, it causes the
inner body to be moved which in turn draws the cooling nozzle 12
along a longitudinal path through the cooling chamber. Accordingly,
the wall of the cooling chamber is cooled along the path of travel
of the cooling nozzle 12. This path of travel creates a linear
lesion along the line of contact between the cooling chamber and
adjacent tissue.
[0028] The expanded gaseous fluid flows, via the discharge channel
formed by the internal lumen 16 in the catheter body and through
the passageways 11a back to the proximal end of the catheter. The
discharge channel of the catheter body is connected in a suitably
sealed-off manner with the line 32 in the deflection knob 5.
[0029] To achieve sufficient cooling effect in the tip of the
catheter 2, the refrigerant is pre-cooled in the heat exchanger 25,
before it is introduced into the catheter. The cooling means
illustrated schematically in FIG. 3 comprises an insulated cooling
chamber 26, through which a connecting pressure tube 27 extends in
a helical pattern. The pressure line 23 is connected with this
connection tube 27. The fluid under pressure is supplied to the
connection tube 27 from a refrigerant source illustrated here as a
gas cylinder 7. The required quantity is regulated by means of the
adjustable valve 29.
[0030] Preceding the valve 29 a line branches off from the
refrigerant line which, via a restriction 34, opens out into the
cooling chamber 26. The quantity of fluid supplied to the cooling
chamber 26 is regulated by the size and the dimensions of the
restriction 34 and the control valve 30. On passing the restriction
34 the refrigerant expands in the chamber 26 and removes heat from
the surroundings, that is to say from the refrigerant flowing
through the connecting tube 27 which is cooled as a result. The
expanded fluid is extracted from the chamber 26 through the line
31, so that a sufficient pressure difference is maintained across
the restriction.
[0031] As shown in FIG. 3, a temperature sensor 22 has been
arranged at the proximal end of the pressure line, which is
connected via a signal line 21 with a temperature measuring device.
In this way it is possible to check the temperature of the
refrigerant supplied to the proximal end of the pressure line 23.
The control valve 30 may be regulated on the basis of the
temperature measured. In another embodiment, the control valve 30
may be regulated by a control means on the basis of the temperature
measured with the sensor 22.
[0032] A temperature sensor (not shown) may also be placed at the
tip of the catheter 2. By means of this temperature sensor the
temperature at the tip of the catheter 2 may be monitored. The
value measured by this sensor may be used to adjust the adjustable
valve 29. Alternatively, the adjustable valve 29 may be regulated
automatically in response to the temperature measured at the
tip.
[0033] The catheter device according to the invention is for
instance used to ablate surface tissue inside the heart, when
treating certain cardiac arrhythmias.
[0034] Because of the relatively high heat resistance coefficient
of the material of which the pressure line 23 has been made, the
pre-cooled fluid will at the most absorb only little heat from the
surroundings. Inside the outer body 3 of the catheter 2 the
pressure line 23 forming the inner body 6 extends through the
central lumen. The expanded gas which is being removed from the tip
flows through this lumen. This expanded gas has initially a very
low temperature and is only heated to limited degree in the tip.
The gas flowing through the lumen 16 forming the discharge channel
consequently still has a low temperature, so that as a result none
or only little heating of the refrigerant supplied under pressure
will take place.
[0035] It should be noted that only a possible embodiment has been
illustrated. Other embodiments are possible as well. The heat
exchanger 25 for instance may be integrated into the deflection
knob 5. The pressure line 23 may in that case be surrounded along
more or less its entire length by expanded fluid which is being
discharged, so that the temperature of the pressure fluid may be
controlled accurately. Alternatively, the nozzle configuration may
be radially placed inside the distal end of the pressure tube, or
in other possible configurations.
[0036] These modifications would be apparent to those having
ordinary skill in the art to which this invention relates and are
intended to be within the scope of the claims which follow.
* * * * *