U.S. patent application number 10/349535 was filed with the patent office on 2003-06-26 for deflectable tip guide in guide system.
This patent application is currently assigned to Scimed Life Systems, Inc.. Invention is credited to Mickley, Timothy J..
Application Number | 20030120259 10/349535 |
Document ID | / |
Family ID | 24793362 |
Filed Date | 2003-06-26 |
United States Patent
Application |
20030120259 |
Kind Code |
A1 |
Mickley, Timothy J. |
June 26, 2003 |
Deflectable tip guide in guide system
Abstract
Guide catheters which can be used in percutaneous myocardial
revascularization (PMR) to deliver therapeutic catheters to
difficult to reach heart chamber wall regions. Some guide catheters
include distal regions which can be bent under control from the
proximal region of the catheter. One steerable guide catheter has a
flexible distal region, a more proximal, less flexible intermediate
region, a first lumen for receiving a therapeutic catheter, and an
elongate manipulation member slidably disposed in a second, blind
lumen. The elongate manipulation member can be secured off-center
near the distal end of the flexible distal region. The distal
region can be bent by retracting the manipulation member and
straightened by pushing the manipulation member. Controllably
bendable guide catheters according to the present invention can be
nested inside other, similar guide catheters. The invention also
includes means for resisting free rotation of guide catheters
relative to other adjacent catheters or tubes.
Inventors: |
Mickley, Timothy J.; (Elk
River, MN) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE
SUITE 2800
SEATTLE
WA
98101-2347
US
|
Assignee: |
Scimed Life Systems, Inc.
|
Family ID: |
24793362 |
Appl. No.: |
10/349535 |
Filed: |
January 21, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10349535 |
Jan 21, 2003 |
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09695525 |
Oct 24, 2000 |
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6530914 |
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Current U.S.
Class: |
604/528 |
Current CPC
Class: |
A61M 2025/0161 20130101;
A61M 2025/0063 20130101; A61M 25/0147 20130101; A61M 25/0662
20130101 |
Class at
Publication: |
604/528 |
International
Class: |
A61M 025/01 |
Claims
What is claimed is:
1. A system for performing myocardial revascularization comprising:
a first elongate tube having a distal region, a distal end, a
proximal region, a first lumen therethrough, means for bending said
distal region, and means for controlling said distal region bending
from said proximal region; and a therapeutic catheter having a
distal end slidably disposed within said first tube lumen.
2. A system for performing myocardial revascularization as recited
in claim 1, wherein said therapeutic catheter distal end has a
distal tip having a first position extending distally from said
first tube distal end, a second position retracted proximally
within said first tube distal end, and means for urging said
therapeutic catheter distal end between said first and second
positions.
3. A system for performing myocardial revascularization as recited
in claim 1, wherein said therapeutic catheter distal end includes
means for penetrating said myocardium.
4. A system for performing myocardial revascularization as recited
in claim 1, wherein said first tube has an intermediate region
proximal of said distal region and said distal region is more
flexible than said intermediate region.
5. A system for performing myocardial revascularization as recited
in claim 1, wherein said first tube distal region has a
longitudinal center axis and an off-center location disposed off
said center axis, and said means for bending includes means for
pulling and pushing on said off-center location.
6. A system for performing myocardial revascularization as recited
in claim 5, wherein said means for pushing and pulling includes an
elongate manipulation member operably coupled to said off-center
location and extending proximally at least to said proximal
region.
7. A system for performing myocardial revascularization as recited
in claim 6, wherein said first tube has a second lumen therein and
said elongate manipulation member is disposed in said second
lumen.
8. A system for performing myocardial revascularization as recited
in claim 1, further comprising a second tube having a distal
region, a proximal region, a distal end, and a second lumen
therethrough, said second tube having said therapeutic catheter
disposed within said second lumen, said second tube being disposed
within said first tube first lumen.
9. A system for performing myocardial revascularization as recited
in claim 8, wherein said second tube has means for bending said
second tube distal region and means for extending said second tube
distal region distally from said first tube distal end.
10. A system for performing myocardial revascularization as recited
in claim 9, wherein said second tube further comprises means for
controlling said second tube distal region bending from said second
tube proximal region.
11. A system for performing myocardial revascularization as recited
in claim 10, wherein said second tube means for controlling bending
includes a second elongate manipulation member disposed within said
second tube.
12. A guiding catheter system for performing myocardial
revascularization comprising: a first guide tube having a proximal
region and a first lumen therethrough, said first lumen having an
inside surface; a second guide tube having a proximal region and a
second lumen therethrough, said second guide tube being disposed at
least partially in said first tube first lumen and having an outer
surface opposing said first tube inside surface; and means for
resisting free rotation between said first and second tubes.
13. A guiding catheter system for performing myocardial
revascularization as recited in claim 12, wherein said means for
resisting free rotation is-disposed on said opposing surfaces.
14. A guiding catheter system for performing myocardial
revascularization as recited in claim 13, wherein said means for
resisting free rotation includes a plurality of teeth disposed on
at least one of said opposing surfaces and at least one tooth on
the other said opposing surfaces for engaging said plurality of
teeth.
15. A guiding catheter system for performing myocardial
revascularization as recited in claim 14, wherein said plurality of
teeth is disposed on said first tube outer surface and said at
least one tooth is disposed on said second tube inner surface.
16. A guide catheter for performing myocardial revascularization
comprising: an elongate tube having a distal region, a distal end,
a proximal region, a first lumen therethrough, and a longitudinal
center axis; a second lumen extending from said proximal region to
at least said distal region; and an elongate manipulation member
disposed in said second lumen, being accessible from said proximal
region, and being operably secured to said tube distal region at a
location off-center from said tube longitudinal center axis, such
that said-tube distal region can be bent by proximally pulling on
said manipulation member.
17. A guide catheter for performing myocardial revascularization as
recited in claim 16, wherein said tube has an intermediate region
proximally near said distal region, and said distal region is more
flexible than said intermediate region.
Description
FIELD OF THE INVENTION
[0001] The present invention is related generally to medical
devices. More specifically, the present invention is related to
catheters for performing percutaneous myocardial revascularization
(PMR) which is also referred to as transmyocardial
revascularization (TMR). The present invention includes guide
catheters having proximally controllable distally disposed bendable
regions.
BACKGROUND OF THE INVENTION
[0002] A number of techniques are available for treating
cardiovascular disease such as cardiovascular by-pass surgery,
coronary angioplasty, coronary atherectomy, and stent placement.
These techniques are generally applied to by-pass or open lesions
in coronary vessels to restore patency and increase blood flow to
the heart muscle. In some patients, the number of lesions is so
great, or the location so remote in the coronary vasculature, that
restoring coronary artery blood flow to the heart is difficult.
Transmyocardial revascularization (TMR), also known as percutaneous
myocardial revascularization (PMR), has been developed as an
alternative to these techniques which are directed to bypassing or
removing lesions.
[0003] Heart muscle may be classified as healthy, hibernating, and
"dead." Dead tissue is not dead but is scarred, no longer
contracting, and no longer capable of contracting even if
adequately supplied with blood. Hibernating tissue is not
contracting muscle tissue but is capable of contracting, provided
it is again adequately supplied with blood. PMR is performed by
wounding the myocardium of the heart, often forming and leaving
patent holes, and sometimes injecting angiogenic substances in the
process.
[0004] PMR was inspired in part by observations that reptilian
hearts are supplied in large part by blood supplied directly from
within the heart chambers. In contrast, mammalian hearts are
supplied by blood pumped from the heart, through the aorta, and
back into the heart muscle through the coronary arteries. Positive
results have been observed in some patients receiving PMR
treatments. The positive results may be due in part to blood being
perfused into the myocardium from the heart chambers through holes
into the myocardium which remain open. The positive results are
believed to be due in part to a wound healing response of the
myocardium which includes formation of new blood vessels in the
heart wall, which are believed to connect with the heart chamber
interior and/or other coronary blood vessels. The PMR procedure can
include cutting into the myocardium with therapeutic cutting tips,
burning holes with therapeutic tips having laser or radio frequency
current burning tips. The PMR therapeutic tip can also be used to
inject angiogenic substances, such as growth factors or genes
selected to cause angiogenesis.
[0005] The PMR procedure generally involves insertion of a
therapeutic tip, such as sharp cutting tip, into the heart chamber
or chambers selected for treatment. The cutting tip and associated
inner shaft can be guided into the chamber through a guide
catheter, which may have been inserted into the vasculature a long
distance from the heart. After the inner shaft exits the guide
catheter, the cutting tip is preferably steered to several
positions for forming of several holes in a pattern across the
endocardium. In order to steer the inner shaft and cutting tip, an
outer shaft or tube is sometimes disposed coaxially about the inner
shaft and within the guide catheter. The outer tube can have
structural features at the distal end for bending to various angles
to reach various locations in the heart wall. The outer tube and
inner shaft can be advanced to bring the cutting tip into contact
with the heart wall.
[0006] It may be desirable to revascularize regions of the
endocardium that are difficult to reach using conventional guide
catheters. For example, it may be important to reach areas of
hibernating tissue in superior locations of the left ventricle.
Conventional guide catheters may have difficulty bending
sufficiently to reach some regions.
[0007] What would be desirable is an improved guide device for
steering inner shaft cutting tips into position within the heart
myocardium. What would be desirable is a catheter having greater
reach and maneuverability in the chambers of the heart.
SUMMARY OF THE INVENTION
[0008] The present invention includes guide catheters which can be
used for performing percutaneous myocardial revascularization
(PMR). Guide catheters incorporating the present invention can
provide distal regions that can be bent through varying angles. The
distal region bending is preferably controlled at a proximal region
or proximal end of the guide catheter. One controllably bendable
guide catheter has a first lumen for receiving and delivering a
therapeutic catheter to the guide catheter distal end and beyond.
The guide catheter can also have an elongate manipulation member
extending from the proximal region of the guide catheter to near
the distal end of the guide catheter. The member is preferably
secured to a location off-center from the central longitudinal axis
of the catheter. In one embodiment, the distal end of the member is
bonded to the body of the guide catheter at the distal end of a
second, blind lumen near the guide catheter distal end.
[0009] The manipulation member is a pull wire in some embodiments.
The manipulation member in one embodiment is a flat metallic
ribbon. In some embodiments, the manipulation member is a pull wire
which may be formed from metal. In one embodiment, the member is
capable of both pushing on the distal region to straighten the
distal region and pulling on the distal region through the
off-center attachment point to impart a curve or bend to the distal
region. In another embodiment, the manipulation member is
sufficiently strong only in tension, with a straightening bias in
the distal region used to straighten the distal region when tension
is released. The guide catheter distal region is-preferably formed
of a more flexible material than the more proximal intermediate
guide catheter region.
[0010] A controllably bendable guide catheter, according to the
present invention, can be inserted through a conventional guide
catheter in one PMR system. In another PMR system, the bendable
guide catheter is nested within a second controllably bendable
guide catheter. This can provide for great flexibility in reaching
otherwise hard to reach sites in the endocardium.
[0011] Another aspect of the present invention provides for
inhibiting free rotation between nested, rotating tubes such as the
nested guide catheter tubes. The rotation inhibitor can include
internal and external teeth on opposing external and internal
opposing surfaces, respectively. The teeth can engage each other
and resist rotation between the inner and outer tubes. When the
applied rotational force exceeds a threshold, elastic deformation
of the teeth can allow slippage between the opposed teeth and the
two tubes. Providing resistance to free rotation between the tubes
can lessen the rotation of the two tubes relative to one another in
the case where torque has been applied to one tube, but has not
been translated to rotational motion at the distal end. The applied
torque may have been stored in the intermediate portion of the tube
and can cause unwanted rotation of either tube at the proximal end.
A ratcheting mechanism can be provided which urges the tubes to
stay in position after the treating physician's hands are removed
from the device
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective, cutaway view of a heart having a
PMR therapeutic catheter disposed within a steerable or
controllably bendable guide catheter disposed within a guide
catheter;
[0013] FIG. 2 is a fragmentary, perspective, cutaway view of a
controllably bendable guide tube having a bendable distal region
and an elongate manipulation member;
[0014] FIG. 3 is a fragmentary, perspective view of a steerable
inner guide catheter disposed within an outer guide catheter;
[0015] FIG. 4 is a fragmentary, perspective view of a steerable
inner guide catheter disposed within an outer steerable guide
catheter;
[0016] FIG. 5 is a fragmentary, perspective view of a PMR
therapeutic catheter disposed within a steerable guide catheter
disposed within a guide catheter;
[0017] FIG. 6 is a fragmentary, perspective view of a PMR
therapeutic catheter disposed within a steerable inner guide
catheter disposed within an outer steerable guide catheter disposed
within a guide catheter;
[0018] FIG. 7 is a longitudinal cross-sectional view of a
rotatable, steerable guide catheter disposed within a rotatable
guide catheter disposed within a proximal hub;
[0019] FIG. 8 is a transverse cross-sectional view of the catheter
of FIG. 7 taken through place 8-8, illustrating external teeth on
the rotatable, steerable guide catheter engaged with an internal
tooth on the rotatable guide catheter for inhibiting free rotation
between the two;
[0020] FIG. 9 is a transverse cross-sectional view somewhat similar
to that of FIG. 8, wherein the steerable guide catheter has
external teeth engaged with an internal tooth of the rotatable
guide catheter; and
[0021] FIG. 10 is a detailed view of the inset portion of FIG.
9.
DETAILED DESCRIPTION OF THE INVENTION
[0022] FIG. 1 illustrates a human heart 20 having a left ventricle
22, an inner layer to a heart chamber wall or endocardium 24, a
heart chamber wall or myocardium 26, and an aortic arch 28.
Disposed through the aortic arch is a percutaneous myocardial
revascularization (PMR) device 30, extending into left ventricle 22
and having an outer guide tube 32, an inner guide tube 34, and a
therapeutic catheter therapeutic tip 36 near endocardium 24. As can
be seen from inspection of FIG. 1, left ventricle 22 includes upper
or superior regions that may require a bend in PMR device 30 in
order to reach the superior regions of the myocardium. In the
embodiment illustrated, inner guide catheter 34 includes a bent
distal region for orienting therapeutic catheter tip 36 toward a
target location in the myocardium.
[0023] Referring now to FIG. 2, one embodiment of a steerable or
bendable guide catheter 40 is illustrated in more detail. Guide
catheter 40 includes a distal region 42, an intermediate region 44
disposed proximal of the distal region, and a distal end 46. A
longitudinal center axis 48 is illustrated near distal end 46, as
is an off-center axis 50 disposed laterally offset from center axis
48. Guide catheter 40 includes a lumen 52 for receiving a
therapeutic catheter, or, in some embodiments, another guide
catheter. A second lumen 54 is illustrated, having an elongate
manipulation member 56 disposed within. Second lumen 54 need not
extend through to distal end 46 in most embodiments. In the
embodiment illustrated, elongate manipulation member 56 is secured
to the body of catheter 40 at an off-center attachment point 58
which is located along off-center axis 50. By pulling on
manipulation member 56 which is attached off-center to guide
catheter 40, distal region 42 can be made to bend or deflect. In
one embodiment, manipulation member 56 is sufficiently strong in
tension to pull distal region 42 to bend the region, and
sufficiently strong in compression to push distal region 42 to
straighten the region. In one embodiment, manipulation member 56 is
a flat wire. In one embodiment, manipulation member 56 is a pull
wire strong enough in tension to bend distal region 42 but
insufficiently strong in compression to straighten distal region
42, with distal region 42 being biased to a straight position and
resuming that position when the tension of manipulation member 56
is released.
[0024] Guide catheter 40 distal region 42 is preferably formed of a
more flexible material than intermediate region 44. In the
embodiment illustrated, distal region 42 is bonded to intermediate
region 44 along a plane as illustrated at 60. In one embodiment,
distal region 42 and intermediate region 44 are formed of materials
such as polyether ester elastomer (for example, ARNITEL.RTM.,
available from DSM Engineering Plastics), a polyester elastomer
(for example, HYTREL.RTM., available from DuPont Corporation), a
polyether block amide (for example, PEBAX.RTM.), or Nylon. The two
regions can be bonded together using a method well known to those
skilled in the art, such as adhesive application or heat bonding.
In one embodiment, intermediate region 44 is formed from the same
polymer as distal region 42, but having a higher durometer
value.
[0025] Referring now to FIG. 3, steerable guide catheter 40 having
bendable distal region 42 is shown disposed within a second guide
catheter 62 having a bent distal region 64. In some embodiments,
distal bent region 64 is relatively fixed in the degree of bend,
and the bend may be used in part to gain entry to the left
ventricle. The length of guide catheter 40 that extends from second
guide catheter 62 can be varied to reach varying locations of the
endocardium in the heart chambers such as the left ventricle. The
distal bend of guide catheter 40 can be used to point a therapeutic
catheter to various locations in the heart wall. Guide catheter
distal region 42 is illustrated in a first bend position "A" and a
second, straighter bend position "B". In the embodiment
illustrated, movement between positions A and B is accomplished
through the longitudinal movement of elongate manipulation member
56.
[0026] Referring now to FIG. 4, guide catheter 40 is shown disposed
within a steerable second guide catheter 66 having a distal bend
region 68. Guide catheter 40 is shown in two positions, "C" and
"D", while second steerable guide catheter 62 is illustrated in two
positions, "E" and "F." Second steerable guide catheter 66 controls
the bend of distal region 68 through a slidable elongate
manipulation member 64. As shown in FIG. 4, the combination of two
independently controlled degrees of bending allows a large degree
of control over where in the heart chamber a carried therapeutic
catheter tip is to be delivered.
[0027] FIG. 5 illustrates a therapeutic cutting tip catheter 80
disposed within a bent, steerable guide catheter 82 slidably and
rotatably disposed within an outer guide catheter 84. FIG. 5
illustrates the range of motion possible through rotation and axial
movement, with rotation indicated at 88 and axial movement
indicated at 86. These ranges of movement are also possible in
addition to the illustrated controlled bending illustrated in FIGS.
3 and 4, but difficult to show on the same figure.
[0028] FIG. 6 illustrates yet another embodiment, illustrating
therapeutic cutting tip catheter 80 slidably disposed within a
first bendable guide catheter 90 which is slidably and rotatably
disposed within a second bendable guide catheter 92, which is in
turn slidably and rotatably disposed within a third, more
conventional guide catheter 94. The range of motion of guide
catheter 90 is indicated by rotation at 96, axial movement at 104,
and bending at 106. Similarly, the range of motion of guide
catheter 92 is indicated by rotation at 102, axial movement at 98,
and bending at 100.
[0029] In one embodiment, guide catheters 90 and 92 are controlled
with an elongate manipulation member similar to guide catheters 40
and 66 of FIG. 4. FIG. 6 thus illustrates how bendable, steerable
guide catheters can be nested within each other to multiple levels
to achieve a large range of motion. With reference to FIGS. 1, 5
and 6, it may be seen that the bendable distal region of the guide
catheters can bring a large portion of the left ventricle
endocardium into range of the catheter therapeutic tip, giving the
ability to treat a large portion of the left ventricle
myocardium.
[0030] Referring now to FIG. 7, another aspect of the present
invention is illustrated. Inspection of FIGS. 4 through 6
illustrates guide tubes disposed within guide tubes. As explicitly
indicated in FIG. 5 at 88 and in FIG. 6 at 96 and 102, rotation of
tubes within tubes is possible. In order to provide the largest
tubular lumens while providing small outer diameters, the nested
guide catheters may be closely matched in size, with little wasted
space in between the outside wall of an inner tube and the inside
wall of an outer tube. In some embodiments, the catheters allow for
more space in between the tubes, but can have one wall lying more
closely to one wall than another, as the nested guide catheters are
curved around tortuous vessels turns which can force the inner
catheter off-center to lie more closely to one inside surface of
the outer catheter.
[0031] The closeness of one or both walls of the inner and outer
catheters can thus inhibit rotation of one tube relative to another
tube. In particular, applied rotational force may not be completely
translated into rotational movement at the far distal end of the
inner catheter. This can result in some applied torque being stored
as torsional energy in the inner catheter. When the treating
physician releases the inner catheter proximal end after applied
torque to the inner catheter, the proximal end of the inner
catheter may spring back. If the outer catheter was being held and
then released, the outer tube may spring in the same direction as
the applied force to the inner tube. Thus, it is possible for one
tube to freely rotate even in the absence of currently applied
force to that tube by the treating physician.
[0032] FIGS. 7 and 8 illustrate a catheter system 120 having
structures for inhibiting the undesirable rotational movement of
one catheter when no torque is being applied at the proximal end by
the treating physician. The structures can prevent the guide
catheters from undesirably rotating one within the other. Catheter
system 120 includes a proximal region 123, and a proximal hub 122
having a lumen 124 therein for receiving a first guide catheter
126, which is disposed about a second guide catheter 128. In the
embodiment illustrated, first guide catheter 126 has a distal
region 127 having a bend and second catheter 128 also has a distal
region 129 having a bend. In one embodiment, second catheter distal
region 129 can be bent, with the bending being controlled from a
more proximal region of the catheter. Second catheter 128 can be
rotated relative to first catheter 126, and first catheter 126 can
be rotated relative to enclosing hub 122.
[0033] FIG. 8 illustrates an aspect of the invention which can
inhibit free rotation of first catheter 126 relative to hub 122.
Hub 122 has an internal tooth 130 and first catheter 126 has
several outwardly extending teeth 132 in proximal hub region 123.
When first catheter 126 is rotated relative to hub 122 and/or
second catheter 128 is rotated relative to first catheter 126,
rotational energy may later cause first catheter 126 to rotate. To
inhibit this free rotation, tooth 130 engages teeth 132 and
inhibits this free rotation. When sufficient force is applied, the
teeth can be forced to move over each other, allowing for rotation.
In one embodiment, this movement is possible due to the elastic
deformation of at least one of the pairs of opposing teeth. In one
embodiment, the outer tooth is replaced by multiple teeth. The
inner and outer teeth may be formed of materials such as
DELRIN.RTM. (an acetal plastic available from DuPont Chemical
Company), PEBAX.RTM. (polyether block amide), polyesters,
polycarbonate, ABS (acrylonitrile butadiene styrene), acrylic, or
ULTEM.RTM. (a polyetherimide available from General Electric
Corporation).
[0034] FIG. 9 illustrates another embodiment having teeth on both
an inner and an outer guide catheter. An inner guide catheter 140
is disposed within an outer guide catheter 144, which is in turn
disposed within hub 122. In the embodiment illustrated, inner guide
catheter 140 has several outer teeth 142 which engage a single
inwardly oriented tooth 146 of outer guide catheter 144. In this
embodiment, the free rotation of inner catheter 140 relative to
outer guide catheter 144 is inhibited. FIG. 10 illustrates outer
guide catheter 144 with inwardly disposed tooth 146 in greater
detail. FIGS. 8, 9, and 10 illustrate embodiments of the invention
capable of resisting stored torsional energy from causing free
rotation of the guide catheter when the applied torque is
removed.
[0035] In use, a guide catheter according to the present invention
can be advanced to a target site. In some methods, this is
accomplished by first introducing a guide wire through the
vasculature and into a heart chamber to be treated, such as the
left ventricle. For example, a guide wire can be introduced into
the femoral artery near the groin, and advanced over the aortic
arch and into a chamber of the heart. A guide catheter can then be
advanced over the guide wire. The first guide catheter can be
followed by a second guide catheter, either over the first guide
catheter or over the guide wire within the first guide catheter.
The guide wire can be retracted and a therapeutic catheter advanced
through the inner most guide catheter. Multiple guide catheters can
thus be advanced to position.
[0036] In some applications of the present invention, a steerable
guide catheter having a controllably bendable distal region is
disposed within a conventional guide catheter. The conventional
guide catheter can terminate distally in either a straight distal
region or a curved distal region, depending on the application. In
other applications, a first guide catheter having a controllably
bendable distal region is disposed within a second guide catheter
having a controllably bendable guide catheter. In either case, the
guide catheter or catheters can be advanced into the heart chamber
with the therapeutic catheter tip disposed within the inner most
guide catheter.
[0037] The innermost guide catheter can be extended toward a target
site of interest with the longitudinal extension and radial
rotation of the catheter proximally controlled by the treating
physician. The bending of the guide catheter distal region can also
be controlled by the treating physician. In preferred embodiments,
at least a portion of the therapeutic catheter or therapeutic tip
is radiopaque to make the tip location visible under fluoroscopy.
The extension, rotation, and bending can be observed under
fluoroscopy, with the extension, rotation, and manipulation of
bending controlled in response to the image seen under fluoroscopy.
In some methods, one or two of the movements, extension, rotation,
or bending, may be controlled while the other one or two movements
are varied in order to cover a pattern of the heart wall. For
example, the rotation may be held constant, and the bend may be
varied, with the longitudinal extension being varied sufficiently
to reach the heart wall. For example, the bend may be held
constant, and the rotation may be varied, to cover a circular
pattern over a portion of the heart wall. In use, various
therapeutic tips may be delivered to the endocardium, including
cutting tips, burning tips, and angiogenic substance injecting
tips.
[0038] Numerous advantages of the invention covered by this
document have been set forth in the foregoing description. It will
be understood, however, that this disclosure is, in many respects,
only illustrative. Changes may be made in details, particularly in
matters of shape, size, and arrangement of parts without exceeding
the scope of the invention. The invention's scope is, of course,
defined in the language in which the appended claims are
expressed.
* * * * *