U.S. patent application number 09/797125 was filed with the patent office on 2001-07-12 for apparatus and method for contemporaneous treatment and fluoroscopic mapping of body tissue.
Invention is credited to MacKin, Robert A..
Application Number | 20010007937 09/797125 |
Document ID | / |
Family ID | 22796474 |
Filed Date | 2001-07-12 |
United States Patent
Application |
20010007937 |
Kind Code |
A1 |
MacKin, Robert A. |
July 12, 2001 |
Apparatus and method for contemporaneous treatment and fluoroscopic
mapping of body tissue
Abstract
An apparatus for contemporaneously treating a sequence of
treatment sites in an internal organ and creating a viewable map of
the treated sites includes a first catheter having a proximal end
and a distal end for insertion through a body passage to tissue
needing treatment. A needle assembly is attached to the distal end
of the first catheter to permit injection of fluid into treatments
sites of the tissue. A fluid injection assembly is connected to the
proximal end of the first catheter and containing predetermined
amounts of radiographic contrast agent and treatment agent for
injection into the various treatment sites. A radiographic
visualizing apparatus is aimed at the treatment sites, including a
display screen for displaying the extent of migration of
radiographic contrast agent around each treatment site after
injection, so that a radiographic marking appears on the display
screen for a predetermined amount of time after each injection,
showing which treatment sites have been treated. In another
embodiment a second catheter having a distal end with a treatment
element attached to its distal end and a control apparatus attached
to its proximal end is used to perform treatment of the tissue
contemporaneously with injection of radiographic contrast agent
into the tissue.
Inventors: |
MacKin, Robert A.;
(Flagstaff, AZ) |
Correspondence
Address: |
Charles R. Hoffman
CAHILL, SUTTON & THOMAS P.L.C.
Ste. 155
2141 East Highland Avenue
Phoenix
AZ
85016
US
|
Family ID: |
22796474 |
Appl. No.: |
09/797125 |
Filed: |
February 27, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09797125 |
Feb 27, 2001 |
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09213778 |
Dec 17, 1998 |
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6193763 |
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Current U.S.
Class: |
604/508 ; 604/20;
604/510 |
Current CPC
Class: |
A61B 18/24 20130101;
A61B 2017/22074 20130101; A61B 17/3478 20130101; A61B 2090/3933
20160201; A61B 2017/22069 20130101; A61B 90/361 20160201; A61B
2018/00392 20130101; A61B 2017/00247 20130101 |
Class at
Publication: |
604/508 ;
604/510; 604/20 |
International
Class: |
A61N 001/30; A61M
031/00 |
Claims
What is claimed is:
1. An apparatus for contemporaneously treating a sequence of
treatment sites in an internal organ and creating a viewable map of
the treated sites, comprising: (a) a first catheter having a
proximal end and a distal end for insertion through a body passage
to tissue needing treatment; (b) a needle attached to the distal
end of the first catheter to permit injection of fluid into
treatment sites of the tissue; (c) a fluid injection assembly
connected in fluid communication with the proximal end of the first
catheter and containing radiographic contrast agent and treatment
substance for contemporaneous injection of the radiographic
contrast agent and treatment substance into the various treatment
sites; and (d) radiographic visualization apparatus aimed at the
treatment sites, including a display screen for displaying the
extent of migration radiographic contrast agent around each
treatment site after injection, whereby radiographic marking
appears on the display screen for at least a predetermined amount
of time after each injection, indicating where treatment has been
performed.
2. The apparatus of claim 1 including an outer catheter extending
through the body passage to effectuate introducing the first
catheter through the body passage to the injection site.
3. The apparatus of claim 2 including a working well balloon
affixed to a distal end of the outer catheter for abutting a wall
of the tissue.
4. The apparatus of claim 2 wherein the first catheter is included
in a needle catheter assembly including a sheath and an element
connected to the proximal end of the first catheter to retract and
advance the first catheter in the sheath.
5. The apparatus of claim 1 wherein the fluid injection assembly
includes a first syringe containing the radiographic contrast
agent.
6. The apparatus of claim 5 wherein the fluid injection assembly
includes a second syringe containing the treatment substance and a
manifold fed by the first and second syringes, the manifold
including an outlet port connected in fluid communication with the
proximal end of the first catheter.
7. The apparatus of claim 5 wherein the first syringe also contains
the treatment substance.
8. An apparatus for contemporaneously treating a sequence of
treatment sites in an internal organ and creating a viewable map of
the treated sites, comprising: (a) a first catheter having a
proximal end and a distal end for insertion through a guiding
catheter extending through a body passage to tissue needing
treatment; (b) a needle attached to the distal end of the first
catheter to permit injection of fluid into treatment sites of the
tissue; (c) a fluid injection assembly connected in fluid
communication with the proximal end of the first catheter and
containing radiographic contrast agent for injection of the
radiographic contrast agent into the various treatment sites; (d)
radiographic visualization apparatus aimed at the treatment sites,
including a display screen for displaying the extent of migration
radiographic contrast agent around each treatment site after
injection, wherein radiographic marking appears on the display
screen for at least a predetermined amount of time after each
injection, indicating which treatment sites have been treated; and
(e) a treatment device extending through the guiding catheter to a
treatment site and a control apparatus coupled to a proximal end of
the treatment device for controlling treatment of the tissue
contemporaneously with injection of radiographic contrast agent
into the tissue.
9. The apparatus of claim 8 wherein the treatment element includes
one of a laser fiber.
10. An apparatus for contemporaneously treating a plurality of
treatment sites in an internal organ and creating a viewable map of
the treated sites, comprising: (a) a first catheter, having a
proximal end and a distal end, for insertion through a body passage
to tissue of the organ needing treatment; (b) a needle attached to
the distal end of the first catheter to permit injection of fluid
into treatment sites of the tissue; (c) a fluid injection assembly
connected in fluid communication with the proximal end of the first
catheter and receiving both radiographic contrast agent and
treatment substance for contemporaneous injection of the
radiographic contrast agent and the treatment substance into the
various treatment sites; and (d) radiographic visualization
apparatus aimed at the treatment sites, including a display screen
for displaying the extent of migration radiographic contrast agent
around each treatment site after injection, wherein radiographic
marking appears on the display screen for at least a predetermined
amount of time after each injection, indicating which treatment
sites have been treated.
11. A method for contemporaneously treating a sequence of treatment
sites in an internal organ and creating a viewable map of the
treated sites, comprising: (a) advancing a first catheter, having a
proximal end and a distal end and a needle attached to the distal
end to permit injection of fluid through a guiding catheter,
through a body passage and inserting the needle into tissue needing
treatment; (b) injecting radiographic contrast agent through the
first catheter and the needle into a treatment site of the tissue;
(c) injecting treatment substance through the first catheter and
the needle into the treatment site; (d) aiming a radiographic
visualization apparatus at the treatment site, and displaying the
extent of migration radiographic contrast agent around the
treatment site after injection on a display screen associated with
the radiographic visualization apparatus; and (e) repeating steps
(b) through (d) for a plurality of different treatment sites,
whereby radiographic marking appears on the display screen for at
least a predetermined amount of time after each injection,
indicating where treatment has been performed.
12. The method of claim 11 wherein step (b) is performed before
step (c).
13. The method of claim 11 wherein steps (b) and (c) are performed
simultaneously.
14. A method for contemporaneously treating a sequence of treatment
sites in an internal organ and creating a viewable map of the
treated sites, comprising: (a) advancing a first catheter, having a
proximal end and a distal end and a needle attached to the distal
end, through a guiding catheter through a body passage and
inserting the needle into tissue needing treatment; (b) advancing a
treatment device through the guiding catheter to the tissue; (c)
injecting radiographic contrast agent through the first catheter
and the needle into a treatment site of the tissue; (d) operating
the treatment device by means of a control apparatus coupled to a
proximal end of the treatment device; (e) aiming a radiographic
visualization apparatus at the treatment site, and displaying the
extent of migration radiographic contrast agent around the
treatment site after injection on a display screen associated with
the radiographic visualization apparatus; and (f) repeating steps
(c) through (e) for a plurality of different treatment sites,
whereby radiographic marking appears on the display screen for at
least a predetermined amount of time after each injection,
indicating where treatment has been performed.
15. The method of claim 14 wherein steps (a) and (b) are performed
simultaneously.
16. The method of claim 14 wherein step (c) is performed before
step (d).
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to an apparatus and technique for
treatment and fluoroscopic mapping of treated tissue by injection
of radiographic contrast agent into the tissue and contemporaneous
treatment of the same tissue to provide a radiographic visual map
of treated locations. The invention also relates to use of such
apparatus and technique to promote revascularization of heart
muscle/tissue.
[0002] Recent research and investigation suggests that part of the
process of healing wounds in human tissue is dependent on blood
vessel growth, which is believed to be in turn dependent on release
of angiogenesis or blood vessel growth factors by the ischemic (or
injured) tissue. It has been suggested at a recent conference on
angiogenesis and direct myocardial revascularization that any
method, i.e., laser, radio frequency electromagnetic signals, or
other technique that results in myocardial tissue ischemia (or
injury) may result in release of angiogenesis growth factors and
development of blood vessel growth and blood flow to the
ischemic/injured area. (As used herein, the term "ischemic" is
intended to refer to reversible tissue damage and the term "injury"
is intended to refer to irreversible tissue damage.)
[0003] While there are publications of references that disclose
dyeing tissue of the heart during direct open heart surgery to mark
lased or otherwise treated sites thereof, and although there are
prior references disclosing introduction of radiographic contrast
agent into various organs such as the chambers of the heart or
coronary arteries for the purpose of radiographic imaging of the
contractions of the heart, the prior art does not disclose use of
needles or other means installed on distal ends of catheters to
inject radiographic contrast agents into heart muscle or other
tissue. In fact, in prior practice injection of radiographic
contrast agent directly into tissue is deliberately avoided.
However, angiogenesis factors alone have been injected into heart
muscle tissue.
[0004] My patent U.S. Pat. No. 4,976,710 entitled "WORKING WELL
BALLOON METHOD", issued Dec. 11, 1990, incorporated herein by
reference, discloses a working well balloon catheter and method for
visualizing and performing procedures on the inner myocardial
wall.
[0005] There is an unmet need for an improved apparatus and
technique for performing medical procedures on tissue within the
body, especially within the heart, and repetitively
radiographically marking contemporaneously treated sites so the
physician can avoid multiple treatments of the same areas, to avoid
complications such as perforation of the heart, to facilitate
completion of a procedure to decrease radiation exposure of the
patients, and to reduce overall costs by providing a more efficient
method of treatment. In contrast, conventional radiography does not
provide a way to determine if an internal area already has been
subjected to contemporaneous treatment.
SUMMARY OF THE INVENTION
[0006] Accordingly, it is an object of the invention to provide an
apparatus and technique for repetitively effectively treating and
effectively marking treated sites within an internal organ.
[0007] It is another object of the invention to provide an
apparatus and technique to promote safe, rapid and effective
marking and revascularization of internal organs such as the
heart.
[0008] It is another object of the invention to provide an
apparatus and technique to contemporaneously mark and reduce
harmful vascularization in tumorous tissue.
[0009] It is another object of the invention to provide an
apparatus and technique for reducing or avoiding the need to
perform bypass surgery.
[0010] It is another object of the invention to provide an
apparatus and method for reducing or avoiding the need to perform
an angioplasty procedure.
[0011] Briefly described, and in accordance with one embodiment
thereof, the invention provides an apparatus for contemporaneously
treating a sequence of treatment sites in an internal organ and
creating a viewable map of the treated sites, including a first
catheter having a proximal end and a distal end for insertion
through a body passage to tissue needing treatment. A needle
assembly is attached to the distal end of the first catheter to
permit injection of fluid into treatments sites of the tissue. A
fluid injection assembly is connected to the proximal end of the
first catheter and containing a predetermined fluid mixture of
radiographic contrast agent and treatment substance for injection
into the various treatment sites. A fluoroscopic visualization
apparatus -is aimed at the treatment sites, including a display
screen for displaying the extent of radiographic contrast agent
around each treatment site after injection. Radiographic markings
appear on the display screen for a predetermined amount of time
after each injection showing which treatment sites have been
treated. In one embodiment a guide wire is introduced to extend
through the body passage to effectuate introducing an outer or
sheath catheter through which the first catheter then is passed to
the desired treatment site. In one embodiment, a working well
balloon is affixed to the distal end of a sheath catheter to abut a
wall of the tissue. A second catheter having a distal end with a
treatment element, such as a needle, laser lens, biopsy forceps,
etc. attached to its distal end and a control apparatus attached to
its proximal end can be used for controlling treatment of the
tissue contemporaneously with injection of radiographic contrast
agent into the tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a partial section view diagram of a working well
balloon catheter pressed against the myocardial wall within a
heart, with a needle for injection of radiographic contrast agent
into the myocardial tissue.
[0013] FIG. 2 is a partial section view similar to that of FIG. 1,
with an additional catheter for performing a lasing, biopsy, or
other medical procedure, with the other catheter being used to
contemporaneously inject contrast agent into the myocardial tissue
at the treatment site to thereby provide a fluoroscopic treatment
map.
[0014] FIG. 3A is a diagram of an embodiment of the invention in
which a contrast agent and a treatment substance both are
introduced through a catheter positioned in an artery and extending
into the interior of the heart, and injected through a needle on
the distal end of the catheter into the heart muscle.
[0015] FIG. 3B is a diagram of a catheter in which radiographic
contrast agent is introduced from the proximal end of a catheter
extending through an artery and into the interior of the heart, and
injected by a distal needle into the heart muscle and the injection
site is contemporaneously treated by a laser beam advanced through
a fiber within the catheter from a proximal laser source.
[0016] FIG. 3C is a diagram of the needle catheter assembly 11
shown in FIG. 3A.
[0017] FIG. 4 is a diagram of a machine for fluoroscopically
visualizing the spots at injection sites in the heart using the
apparatus of FIG. 1 or FIG. 2.
[0018] FIG. 5 is a diagram illustrating injection from a needle
catheter introduced through the aorta to introduce the tip of a
needle on the distal end of the needle catheter through the heart
muscle and into the pericardial sac for the purpose of draining the
pericardial sac and/or introducing therapeutic substance such as
angiogenesis factor or anti-arrhythmic substance into the
pericardial sac.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring to FIG. 1, a catheter 101 is inserted through an
outer catheter 6 having a working well balloon 7 of the type
described in my above referenced patent U.S. Pat. No. 4,976,710.
Working well balloon 7 is pressed against the interior of
myocardial wall or heart muscle 28. The working well balloon
assembly 6,7 may be introduced through a major artery such as the
femoral artery or aorta, as indicated in FIG. 8 of above referenced
patent U.S. Pat. No. 4,976,710.
[0020] In accordance with one embodiment of the present invention,
a needle assembly 102 is provided on the distal end of catheter
101, and a certain amount of radiographic contrast agent is
injected into the heart muscle 28. The radiographic contrast agent
can, for example, be ISOVIEW or OMNIPAQUE. The amount can be in the
range from a fraction of a cc (cubic centimeter) to several cc. The
injected contrast agent forms a mark 103 which has the appearance
of a large asterisk and remains visible during conventional
radiography. After the marking 103 has been formed and the
proximate tissue has been contemporaneously treated in some manner,
the working well balloon 7 is moved to an adjacent location. (The
term "contemporaneous" as used herein is intended to refer to acts
which occur at the same time or approximately the same time. For
example, acts which occur within a few seconds to a few minutes of
each other are considered to be contemporaneous.) The procedure is
repeated, and another radiographically viewable marking 103 is
produced in the myocardial muscle tissue 28 by injecting the
radiographic contrast agent. This process is repeated to create a
map of treated tissue locations which are radiographically viewed
during the entire procedure. (The term "radiographic" procedure as
used herein is intended to include but not limited to common
fluoroscopy.)
[0021] The portion of the heart marked in this manner could be a
portion of the heart muscle that is not receiving adequate blood
supply and nourishment such as oxygen because of a plaque blockage
in an artery. In that case it is assumed that the patient may be in
need of conventional coronary bypass surgery or a conventional
angioplasty procedure, which includes insertion of a suitable blood
vessel extending from the aorta beyond the plaque blockage to a
segment of the blood vessel beyond the blockage to provide
nourishment to myocardial tissue that is being starved as a result
of the blockage.
[0022] In accordance with one embodiment of the present invention,
the amount of radiographic contrast agent injected at each
treatment site may be sufficient to cause ischemia/injury in the
tissue proximate to each stain spot 103. The ischemia/injury
actually can constitute part or all of the contemporaneous
treatment, because the ischemia/injury may cause release of
angiogenesis factors. Angiogenesis factors or blood vessel growth
factors have been shown to induce the development of blood flow
within a few days of the healing process. Within just a few weeks,
the previously blood-starved myocardial tissue can become
re-vascularized with a network of blood vessels that adequately
nourish it, making the coronary bypass operation or an angioplasty
procedure unnecessary.
[0023] FIG. 2 shows a diagram similar to FIG. 1, except that an
additional catheter 110 is introduced through the main channel of
catheter 6 of the working well balloon assembly. The second
catheter 110 can be utilized to perform lasing, chemical injection
treatment, biopsy tissue removal, or any of the other treatment
procedures mentioned in the above-identified U.S. Pat. No.
4,976,710 patent. Each time such treatment is performed by means of
catheter 110, catheter 101 and needle 102 also are used to inject
enough radiographic contrast agent to produce a radiographically
observable marking 103 at the location of the treatment
contemporaneously accomplished by means of the other catheter 110.
A map of radiographic markings of the treated areas of the heart is
thereby created and observed during the treatment procedure to
ensure that all desired portions of the heart tissue are treated,
and also to ensure that no portion of the heart tissue is treated
more than is necessary.
[0024] In accordance with another broader aspect of the method of
the present invention, instead of injecting enough of the
radiographic contrast agent to cause physical injury of tissue
around the point of injection, the injected fluid contains a
mixture of (1) a sufficient amount of the radiographic contrast
agent to adequately mark the injection site and thereby allow
radiographic imaging thereof for a desired period of time, and (2)
a suitable amount of a treatment substance. The treatment substance
could include angiogenesis factor, or other suitable therapeutic
substance. For example, if the tissue being stained is tumorous or
cancerous tissue, angiogenesis blocking factors or other caustic or
tissue-destructive substances can be injected contemporaneously
with the radiographic contrast agent to retard, rather than promote
vascularization.
[0025] The most basic technique of the invention does not have to
be used in conjunction with the working well balloon as described
above with reference to FIGS. 1 and 2. In its broadest aspect, the
invention simply constitutes (1) use of a catheter and associated
distal needle to achieve radiographic marking of selected tissue
site by radiographic contrast agent anywhere in the human body, and
(2) contemporaneous physical or chemical treatment of the same
tissue sites, using the same catheter and/or a different catheter
and/or a laser fiber.
[0026] Referring to FIG. 3A, a catheter assembly 10 includes a
needle catheter assembly 11 introduced, typically through a femoral
artery and through the aorta, into a chamber of the heart, for
example the left ventricle. Needle catheter assembly 11
(subsequently described with reference to FIG. 3C) normally would
be introduced through an outer guide catheter of which is indicated
by dashed line 6A. Guide catheter 6A usually would be introduced
earlier with aid of a guide wire (not shown) which then is removed.
Needle catheter assembly 11 has a retractable needle 13 on its
distal end.
[0027] Referring to FIG. 3C, needle catheter assembly 11 includes
an outer catheter or sheath 22 and a needle catheter 23. Needle
catheter 23 includes a catheter tube 23A extending through sheath
22. A locking hub 12 connected to the proximal end of sheath 22
performs the function of locking needle catheter 23 to sheath 22
with needle 13 retracted during introduction of needle catheter
assembly 11 through guiding catheter 6A (FIG. 3A). An injection
needle 13 is rigidly attached to the distal end of catheter tube
23A. The proximal end of catheter 23A extends through locking hub
12 beyond the proximal end of sheath 22, and opens into the outlet
port of subsequently described manifold 14 to receive a flow 21 of
fluid being injected from one or both of syringes 15 and 19. The
proximal end of catheter tube 23 is engaged by a handpiece 24
having finger eyelets 25 to allow needle catheter 23 to be
retracted to a retracted configuration as shown in FIG. 3C and
locked to sheath 22 as needle catheter assembly 11 is advanced to
the desired site. Then locking hub can be loosened, and handpiece
24 is manipulated to advance needle 13 beyond the distal end 22A of
sheath 22 as shown in FIG. 3A into heart muscle or other tissue so
that radiographic contrast agent and/or treatment substance can be
injected therein. (Needle 13 needs to be retracted during
introduction of needle catheter assembly 11 through guide catheter
6A (FIG. 3A) to prevent damage to guiding catheter 6A.)
[0028] The proximal end of catheter tube 23A of needle catheter
assembly 11 is connected to the outlet port of three port manifold
14. A syringe 15 is in fluid communication with the interior of
manifold 14. Syringe 15 contains radiographic contrast agent by
means of which the physician can inject radiographic contrast agent
through a needle catheter assembly 11 and needle 13 thereof into
heart muscle or other tissue of an internal organ.
[0029] A second syringe 19 includes treatment substance, for
example angiogenesis growth factor, which can be injected through
manifold 14 into catheter port 12 contemporaneously with the
introduction of the radiographic contrast agent in syringe 15.
Usually it would be best to inject the radiographic contrast agent
into the heart muscle at the injection site first, and then
radiographically visualize the site to be certain that the needle
was properly inserted therein, and then introduce the treatment
substance from syringe 19 into the injection site, to avoid wasting
treatment substance. If the organ or tissue at the injection site
were cancerous, the treatment substance could be a growth-blocking
substance.
[0030] Alternatively, radiographic contrast agent could be mixed
with treatment substance and the mixture could be loaded into a
single catheter which could then introduce the mixture into the
needle catheter assembly 11.
[0031] FIG. 3B shows another embodiment of the invention, in which
catheter assembly 11A includes both a channel by means of which
radiographic contrast agent from a syringe 15A is introduced
through a needle 13 of a needle catheter assembly into heart muscle
tissue at the injection site. Catheter assembly 11A also includes a
second channel through which a laser fiber (or other treatment
device) 32 having a distal end adjacent to needle 13 passes from
port 12A of catheter assembly 11A, through a catheter 34 and a
laser fiber port 33, and through a laser fiber 35 to a laser source
(or other control device) 36. The injection of the radiographic
contrast agent from syringe 15A can be simultaneous with or
contemporaneous with the laser treatment (or other treatment).
(Alternatively, block 36 could contain a mechanism for control of a
radio frequency energy delivery device, a biopsy forceps catheter,
or other device introduced through ports 33 and 12A into catheter
11A, to allow treatment of tissue at the injection site.)
[0032] FIG. 4 illustrates a common fluoroscopy system 45, which
includes a horizontal platform 46 on which a patient 48 lies. A
C-shaped support arm 49 positions a conventional upper X-ray system
component 50 and a corresponding conventional lower X-ray system
component 51 above and below patient 48. A suitable monitor system
53 coupled by a cable 54 to the X-ray system 50,51 provides
continuous monitoring of an image of the radiographic (in this
case, fluoroscopic) agent injected into the heart muscle
tissue.
[0033] FIG. 5 illustrates an alternate embodiment of the invention
in which the tip of needle 13 has been passed all the way through
the heart wall 55 into the pericardial space 57 bounded by
pericardial membrane 56 and the heart wall 55. (Membrane 57 and
space 57 between heart wall 55 constitute the pericardial sac.)
[0034] Typically, the treatment substance or apparatus will be
introduced to each region of the tissue to be treated through a
common outer or sheath catheter, which may or may not have a
working well balloon attached to its distal end. In any case,
radiographic marking of the treated regions is contemporaneously
made with the physical treatment of the tissue thereof, and is
radiographically observed as needed so that the physician can
readily see which regions of the tissue have been treated and which
have not.
[0035] In accordance with the present invention, myocardial
injection of radiographic contrast agent to create radiographic
myocardial marking was performed on three mature swine. A guiding
catheter was introduced through a leg artery and its distal tip was
positioned in the left ventricle. A small gauge needle catheter was
introduced through a guiding catheter into the heart and was used
to inject varying amounts of radiographic contrast agent, from 0.1
cubic centimeters to 2 cubic centimeters, directly into the heart
muscle at various depths. The needle catheter also was allowed to
perforate the heart to inject contrast agent into the pericardium
surrounding the heart. Myocardial staining was performed using hand
pressure injection of radiographic contrast agent. The catheter
then was moved to various sites and the foregoing procedure was
repeated at each site, thus creating a radiographic contrast map.
The swine were monitored for approximately one hour with
intermittent radiography to assess the "time of wash out" of the
marked areas.
[0036] Also during this procedure, coronary angiography was
performed. Radiographic contrast agent was injected into the
coronary arteries to visualize the arterial tree in order to
compare this with subsequent angiography images to determine if any
blood vessels could be visualized. After one month, the swine were
returned to the catheterization laboratory. A catheter was
introduced through the femoral artery. Coronary angiography again
was performed. There was no apparent gross radiographic evidence of
blood vessel growth to the previously treated areas. The hearts
then were sent for microscopic analysis for evidence of blood
vessel growth. Unfortunately, in the preparation process the swine
hearts were mishandled and could not be analyzed.
[0037] However, my visualization during the sequence of site
injections showed that the radiopaque contrast agent remained
radiographically viewable by the system of FIG. 3 for durations
from one to fifteen minutes, depending on the type and amount of
contrast agent used. This appears to be enough time to allow
treatment and associated marking of the entire heart, at injection
sites located approximately one to two centimeters apart, in
approximately fifteen minutes. However, other contrast agents may
allow for longer periods, e.g., for an hour. It is noted that the
above procedure was performed on normal swine hearts. It is quite
possible that if the hearts had been ischemic this "wash-out"
period of the contrast agent would have been longer due to reduced
blood flow.
[0038] Normally, the extent of the treatment around an injection
site would extend roughly one to two centimeters radially outward
from the injection site. In diseased hearts the myocardial marking
may extend outward a different distance from the injection
site.
[0039] An expected benefit of using radiographic contrast agent to
create ischemia/injury is that the degree of injury and the extent
thereof may be estimated by the ability to radiographically image
the extent of myocardial marking in the in vitro intact heart.
[0040] Apart from creation of myocardial ischemia/injury, the
technique of the present invention includes injecting a small
amount of radiographic contrast agent to "mark" sites of the
myocardium of the intact heart to provide a radiographic map for
various contemporaneous catheter-based myocardial revascularization
techniques, including delivery of laser energy, rf (radio
frequency) electromagnetic energy, etc. The radiographic contrast
marking of the myocardium of the intact heart provides the operator
the opportunity to achieve more effective revascularization of
heart muscle tissue by providing a continuous contemporaneous
marking of the treated regions, thereby avoiding potential
complications such as myocardial perforation by avoiding an already
treated region.
[0041] While the invention has been described with reference to
several particular embodiments thereof, those skilled in the art
will be able to make the various modifications to the described
embodiments of the invention without departing from the true spirit
and scope of the invention. It is intended that all elements or
steps which are insubstantially different or perform substantially
the same function in substantially the same way to achieve the same
result as what is claimed are within the scope of the
invention.
* * * * *