U.S. patent application number 10/622644 was filed with the patent office on 2004-02-05 for catheter system for performing intramyocardiac therapeutic treatment.
Invention is credited to Bombardini, Tonino, Marcelli, Emanuela, Plicchi, Gianni.
Application Number | 20040024371 10/622644 |
Document ID | / |
Family ID | 26330382 |
Filed Date | 2004-02-05 |
United States Patent
Application |
20040024371 |
Kind Code |
A1 |
Plicchi, Gianni ; et
al. |
February 5, 2004 |
Catheter system for performing intramyocardiac therapeutic
treatment
Abstract
The multilumen catheter (2) is provided at one end with a needle
system (9, 9') formed by two or more single-lumen needles which are
provided with respective discharge openings (110, 111) and which,
via their longitudinal lumina (10, 11), are connected to
corresponding lumina (3, 4) of the catheter for separate release of
a tracer fluid for external image diagnostics systems and
therapeutic fluids, for example DNA plasmids. The needles may be
both straight or both helical or one of these needles may be
straight and the other needle may be helical.
Inventors: |
Plicchi, Gianni; (Bologna,
IT) ; Bombardini, Tonino; (Imola, IT) ;
Marcelli, Emanuela; (Macerata, IT) |
Correspondence
Address: |
LARSON & TAYLOR, PLC
1199 NORTH FAIRFAX STREET
SUITE 900
ALEXANDRIA
VA
22314
US
|
Family ID: |
26330382 |
Appl. No.: |
10/622644 |
Filed: |
July 21, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10622644 |
Jul 21, 2003 |
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09831493 |
May 10, 2001 |
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6620139 |
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09831493 |
May 10, 2001 |
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PCT/EP99/08686 |
Nov 11, 1999 |
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Current U.S.
Class: |
604/264 ;
604/272; 604/44 |
Current CPC
Class: |
A61B 18/1477 20130101;
A61M 2025/0089 20130101; A61B 17/3478 20130101; A61B 2018/1435
20130101; A61N 1/0575 20130101; A61M 25/0084 20130101 |
Class at
Publication: |
604/264 ;
604/272; 604/44 |
International
Class: |
A61M 025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 1998 |
IT |
BO98A000691 |
Feb 5, 1999 |
IT |
BO99A000050 |
Claims
1. Catheter system for performing intramyocardiac therapeutic
treatment comprising: a catheter having a hollow catheter body
provided on its terminal end with a needle system for the injection
of fluids through said catheter; the body of the catheter having at
least two longitudinal lumina which are connected at one end to
external means for administering fluids; the needle system having
at least two longitudinal lumina connected to the corresponding
lumina of the catheter; wherein said longitudinal lumina are
provided with respective lateral discharge openings.
2. Catheter system according to claim 1, in which the terminal end
needle system of the catheter consists of a multilumen needle.
3. Catheter system according to claim 1, in which the at least one
of said longitudinal lumina of the needle system is obtained in a
needle of helical type.
4. Catheter system according to claim 2, in which the multilumen
needle is of the helical type.
5. Catheter system according to claim 1, in which the terminal end
needle system of the catheter is formed by at least two
single-lumen needles.
6. Catheter system according to claim 5, in which the needles which
form the needle system are of different lengths.
7. Catheter system according to claim 1, in which the discharge
openings of the lumina of the needle system are in different
longitudinal positions of the needle itself.
10. Catheter system according to claim 6, in which the shorter
needle is provided with several lateral discharge openings.
11. Catheter system according to claim 5, in which the needle
system is formed by two helical needles of different length which
are centered with respect to the axis of the catheter.
12. Catheter system according to claim 11, in which the helical
needles are arranged alongside each other and fixed with welds, the
tip of the shorter needle being integral with and connected to the
body of the longer needle.
13. Catheter system according to claim 12, in which the helical
needles have a cross section which is flattened and such that the
needle system formed by it has a substantially round cross
section.
14. Catheter system according to claim 12, in which the helical
needles enter into the catheter with straight sections arranged
along the axis of the said catheter.
16. Catheter system according to claim 1, in which the needle
system is formed by a straight needle aligned with the axis of the
catheter and by a helical needle arranged concentrically around
said central needle.
17. Catheter system according to claim 16, in which the central
straight needle is shorter than the helical needle.
18. Catheter system according to claim 16, in which the central
straight needle is longer than the helical needle so as to act as a
centering device and rotational pivot for said helical needle.
19. Catheter system according to claim 16, in which the helical
needle enters into the catheter with a section located alongside
the central needle.
20. Catheter system according to claim 16, in which the helical
needle enters into the catheter with a section distant from the
central needle so as to prevent the rotation of the catheter when
this section comes into contact with the wall of the
myocardium.
22. Catheter system according to claim 1, in which the needle
system is electrically conducting.
23. Catheter system according to claim 22, in which the
electrically conducting needle system is lined with a thin film of
electrically insulating material over nearly the whole of its
length, except for a suitable tip section which remains
electrically conducting.
24. Catheter system according to claim 23, in which the
electrically insulating material which partly lines the needle
system comprises material known as "Parylene".
25. Catheter system according to claim 22, in which the body of the
catheter comprises a first longitudinal electrical conductor
connected at one end to the needle system and designed for
connection at the external end to an external electrical
apparatus.
26. Catheter system according to claim 1, characterized in that the
body of the catheter has an internal longitudinal structure of
meshwork braiding, which allows a twisting torque to be applied to
the external end of the catheter and to ensure that this causes a
corresponding rotation of the multilumen needle system fixed onto
the terminal end of said catheter.
27. Catheter system according to claim, 25 in which the body of the
catheter is provided with a second longitudinal electrical
conductor which is electrically insulated from the conductor
connected to the needle system and designed for connection of the
external end to an external electrical apparatus and for connection
of its terminal end to an electrically conducting ring located on
the terminal end of the catheter and having the function of a
reference electrode for all the operations where the needle system
performs the function of a conductor of electrical impulses.
28. Catheter system according to claim 27, in which the said first
and second electrical conductors are seated, with suitable mutual
insulation, in at least one longitudinal secondary lumen in the
body of the catheter.
29. Catheter system according to claim 28, in which any one of the
said electrical conductors may be constituted by the said twisting
braiding if made of electrically conducting material.
30. Catheter system according to claim 25, in which the external
electrical apparatus comprises a source of electric energy and
electrical impulses.
31. Catheter system according to claim 25, in which the external
electrical apparatus comprises an apparatus for monitoring
electro-physiological signals.
32. Catheter system according to claim 25, in which the external
electrical apparatus comprises an apparatus for measuring the
electrical impedance.
33. Catheter system according to claim 1, in which the body of the
catheter comprises at least one filament-like, longitudinally
extending, flexible conductor of ultrasound energy which is
acoustically coupled to the needle system and designed for
connection at its external end to an external apparatus supplying
ultrasounds.
34. Catheter system according to claim 1, in which the body of the
catheter comprises on its terminal end, at the base of the needle
system, a stopping device of the retractable type, with an external
activating and deactivating control device, for limiting the
penetration of said needle system into the myocardium.
35. Catheter system according to claim 34, in which the stopping
system comprises a torus-shaped balloon which is made of flexible
and impermeable material and which, via a connection duct of its
internal chamber, is connected to the terminal end of a secondary
longitudinal lumen in the body of the catheter, the external end of
which is designed for connection to an external system for
supplying and drawing fluid into and from said balloon,
respectively so as to fill it and activate it for the end-of-travel
function which it must perform, or so as to neutralize it and
ensure that it remains in the retracted condition, which is useful
during insertion and extraction of the catheter.
36. Catheter system according to claim 35, in which the main lumina
in the body of the catheter are intended to convey the tracer
fluid, have the form of a circle segment and are arranged opposite
each other in specular fashion, these lumina having, arranged
between them in a symmetrical manner, a first axial secondary lumen
for receiving the spindle guiding the catheter during use and there
being provided, laterally with respect to this lumen, on the one
hand a second secondary lumen for conveying the fluid filling and
emptying the end-of-travel balloon (13) and, on the other hand, a
third secondary lumen for receiving the electrical conductors, the
ends of which are connected to the needle system and to the annular
reference electrode.
37. Catheter system according to claim 36, in which the lumina of
the catheter, except for the first axial lumen, are closed at the
external front end and the front section of the said catheter
having, mounted on it without the possibility of axial
displacement, a rotating distributor or header provided around the
said catheter with annular chambers which are isolated from each
other and with respect to the exterior by annular sealing gaskets
and into which chambers there lead, via respective radial holes,
the two main lumina which are connected to the base connecting
sections of the needle system and the secondary lumen leading to
the end-of-travel balloon, these chambers being provided with
respective hollow connectors for connection to flexible pipes and
to syringes containing respectively the fluid for filling and
emptying said balloon, the tracer fluid and the therapeutic
fluid.
38. Catheter system according to claim 37, in which the distributor
or header is made of electrically insulating material and is
provided with electrical conductors having brushes which allow an
external electrical apparatus to be connected to the electrical
conductors which are connected to the needle system and to the
annular reference electrode, the said brushes making contact with
electrically conducting rings which are fixed onto the body of the
catheter, arranged at a suitable distance from each other and
insulated and fixed to the terminals of the said electrical
conductors which emerge from the associated guide lumen through
lateral holes.
39. Catheter system according to claim 5, characterized in that, an
ultrasound generator is mounted on the terminal end of the
catheter, said ultrasound generator being integral with the base of
one or both the needles of the needle system and connected to an
electrical circuit which passes through a secondary lumen of the
catheter for connection to external power supply systems.
40. Catheter system according to claim 1, in which the body of the
catheter has, an external diameter of about 7 French, that is about
2.1 mm.
41. Catheter system according to claim 1, in which the diameter of
the helix of the needle system with at least one helical needle is
about 2 mm.
42. Catheter system according to claim 6, in which the length of
the projecting section of the longer needle of the needle system
does not exceed, 5 mm, while the length of the projecting section
of the shorter needle is about 2.5 mm.
43. Catheter system according to claim 5, in which the external
diameter of each of the needles which form the needle system is
about 0.30 mm.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional or of application Ser. No.
09/831,493, which is the National Stage of International
Application No. PCT/ep99/08686, filed Nov. 11, 1999.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a method and the associated
apparatus for performing intramyocardiac therapeutic treatment by
means of the controlled infusion, in this anatomical location, of
therapeutic fluids of varying nature and composition. With this
method and apparatus it is possible to treat patients who suffer
from cardiac ischaemia and who are not able to tolerate surgical
therapy involving a coronary bypass or coronary angioplasty using
catheters. At present there are many patients suffering from heart
disease which is advanced to the point where it can no longer be
treated using the solutions mentioned. Complete re-vascularization
is not possible in 20% of the patients who undergo bypass surgery.
The patients who cannot be treated with the abovementioned
solutions belong, for example, to the following categories:
patients with extensive heart disease affecting the distal vessels;
patients with symptomatic ischaemia resulting from a diseased
vessel which is too small to be bypassed; patients who do not have
adequate ducts for bypassing; patients with total chronic occlusion
and with distal vessels which are small and/or cannot be
viewed.
[0003] A new therapy which is currently becoming more widespread
for the treatment of this type of patient consists in the
percutaneous injection, into the cardiac muscle, of genic
substances, for example DNA plasmids, which induce the formation of
new blood vessels. At least six different carrier systems have been
used for genic transfer to the heart muscle cells, namely: DNA
devoid of viral or physical adjuvants which increase the genic
release; DNA encapsulated in modified liposomes; DNA complexed with
cationic liposomes; retroviral carriers; adeno-associated viral
carriers. This therapy is currently performed by making a small
incision in the chest in order to inject the abovementioned
plasmids into the myocardium, continuously monitoring the patient
by means of transoesophageal echocardiography in order to check the
movement of the cardiac wall during the percutaneous injection, in
order to prevent the plasmid being injected into the blood, inside
the cavity of the left-hand ventricle. The recent clinical
experiments involving injection of plasmids into the myocardium,
during surgical treatment or a mini-thoracotomy, are very
interesting, but are unable to solve many problems when this
procedure is used as the one and only therapy, in particular
problems relating to optimization of the most suitable site for
injection and the number and dosing of the intramyocardial
injections. It is also obvious that the surgical solution limits
very much the possibility of performing multiple treatment or
treatment which is repeated over time.
[0004] It was thought that a catheter system suitable for the
intramyocardiac injection of plasmids may be able to overcome the
limitations of the present surgical solution indicated above.
[0005] According to the publication "Percutaneous Transluminal Gene
Transfer into Canine Myocardium in Vivo by Replication-Defective
Adenovirus" Jian Jun Li et. al. (Cardiovascular Research 1995; 30:
97-105), previous experiments involving the percutaneous injection
of genes into the myocardium of dogs, by means of adenovirus, were
performed using an injection catheter composed of a catheter guide
and a guided catheter, with a needle at its terminal end, inserted
into the left-hand ventricle of the heart. Under a fluoroscope, the
needle was inserted into the myocardium and its correct position of
insertion was confirmed by suction of the blood. If the needle is
inserted into the wall of the cardiac muscle, its lumen is closed
by the muscle itself and therefore the suction of blood is
prevented.
[0006] Various injection catheters have been studied in order to
improve the injection of a drug into an area inside the human body.
Injection catheters have for example been produced by Wilson Cook
Medical Inc. (Cook Italia Srl), said catheters being specifically
designed for the sclerotherapeutic endoscopic treatment of
oesophageal varices. The Boston Scientific Corporation markets
needles for liquid injection therapy using a dedicated twin-lumen
catheter and associated extendable and retractable needle with an
ample washing lumen for ensuring vision with an endoscope in
bleeding conditions.
[0007] None of the catheters with injection needles proposed by the
current technology has been specifically developed and can neither
be adapted to solve the problem of percutaneous and transvascular
injection of plasmids into the human myocardium. With a needle
catheter of the known type it is difficult to maintain a fixed
position inside the moving wall of the myocardium and it is
therefore difficult to inject, in a reliable manner, plasmids into
the said wall. Similar difficulties have been encountered with the
catheters of pacemakers when they have to be positioned in a
different point of the apex of the right-hand ventricle, for
example in the interatrial or interventricular septum. In these
cases, a helical electrode screwed into the wall of the
endocardium, in order to ensure immediate stability of the implant
pending the growth of tissue thereon, is used. The use of a helical
and hollow electrode for the injection of liquids into the human
body has been described in U.S. Pat. No. 5,431,649 for a purpose
different from that of the present invention, namely for the
hyperthermic treatment of neoplasia of the prostate and for
treatment of myocardiac ablation by means of radiofrequency, using
a perfusion of saline solution through the cavity of the helical
electrode.
[0008] An important factor which prevents the use of the
abovementioned catheter perfusion systems for the function in
question is the fact that they are not able to provide a safe,
reproducible and recordable method for demonstrating that the
injection of the plasmids is performed in a selected area of the
myocardium and not in the blood stream; in fact the aforementioned
solution of confirming the position of the needle by suction is not
suitable for this purpose on account of the high risk of false
situations created by the closure of the needle lumen by blood
clots.
[0009] A recent publication "Transcatheter Subendocardial Infusion.
A Novel Technique for Mapping and Ablation of Ventricular
Myocardium", Andreas Goette et. al. (Circulation 1996; 94:
1149-1455) described an infusion catheter equipped with an
electrode corresponding to the injection needle located on the
distal end of said catheter and provided with a second ring
electrode in the vicinity of the same needle. Two lumina which are
formed inside the catheter and by means of which it is possible to
perform a sequential administration of fluid mixtures converge
towards this needle. A tracer substance is injected via a lumen of
the catheter in order to map, by means of fluoroscopy, the point of
injection of the needle into the myocardium of the left-hand
ventricle, while a fluid mixture with ethanol is subsequently
injected through the second lumen of the catheter in order to
perform a chemical ablation of a volume of the myocardium. By means
of this method, with the associated catheter, it is possible to
identify with reasonable certainty the area of the myocardium into
which the needle is inserted, but the problems, as described in the
abovementioned publication, resulting from the difficulty of
keeping a straight needle in the correct position in a beating
myocardium and preventing remixing between the fluids introduced
through the two catheter lumina, the latter intercommunicating via
the common lumen of the injection needle, cannot be solved. Owing
to the inherent elasticity of the material from which the lumina of
the catheter may be made and the notable curvature to which the
catheter itself is subject during insertion into the human body, it
cannot be ruled out that the pressure exerted on a fluid which is
to be injected may cause a partial transfer of this fluid from its
lumen under pressure to the other lumen which is at a lower
pressure, with the result of unexpected and constant mixing of the
two fluids and possible limitation of the volume of,the fluid
actually injected into the myocardium, since a part of this fluid,
instead of being discharged from the needle, flows back into the
lumen of the catheter which is at a pressure less than that of the
active lumen.
[0010] U.S. Pat. No. 5,354,279 ("Plural Needle Injection Catheter")
envisages a catheter provided at its terminal end with a plurality
of thin pre-formed metal needles emerging in a ray-like arrangement
and designed to release pharmaceutical substances onto the
arteries. The lumina of these needles communicate, however, with a
single lumen of the catheter so that this apparatus may not be used
for the purposes of the present invention, either.
[0011] Document U.S. Pat. No. 5,322,510 A (Lindner et al), which
constitutes the closest prior art, discloses a catheter system for
performing a therapeutic treatment, comprising
[0012] a hollow catheter body provided on its terminal end with a
needle system for the injection of fluids through the said
catheter,
[0013] said body of the catheter having at least two longitudinal
lumina which are connected at one end to external means for
administering fluids,
[0014] the needle system having at least two longitudinal lumina
connected to the corresponding lumina of the catheter.
[0015] By way of conclusion, the known art, with the procedures and
the devices described based on a catheter system with injection
needle, does not allow the practical realization of an apparatus
and a method for injecting plasmids solely using the
intramyocardiac method, owing to problems associated with the
movement of the endocardium and the impossibility of separating
completely injection of the therapeutic fluids from injection of
the tracer fluid.
SUMMARY OF THE INVENTION
[0016] The object of the invention is to solve these and other
problems of the already known art by means of a catheter provided
with two or more longitudinal lumina and provided at its terminal
end with a multilumen needle system, each lumen of this needle
system having its own discharge opening and being connected to a
corresponding lumen of the catheter. The lumina of the catheter are
connected to external systems for releasing separately tracer
fluids for external image diagnostics systems by means of which it
is possible to verify the correct position of the needle in the
cardium tissue and release therapeutic fluids, for example DNA
plasmids. The needle system in question may be formed by a
multilumen needle or by several single-lumen needles arranged
alongside each other and each connected to a corresponding lumen of
the catheter.
[0017] More particularly, the present invention relates to a
catheter system of the type as disclosed above with reference to
the cited document U.S. Pat. No. 5,322,510 A, further characterised
by the fact that the said longitudinal lumina are provided with
respective lateral discharge openings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Further characteristic features and advantages arising
therefrom will appear more clearly from the following description
of certain preferred embodiments thereof, illustrated purely by way
of a non-limiting example in the accompanying sheets of drawings,
in which:
[0019] FIG. 1 is an overall side view, with parts shown in cross
section, of the catheter system according to a preferred embodiment
of the invention;
[0020] FIG. 2 shows a cross section through the middle of the
catheter, along the line II-II of FIG. 1;
[0021] FIGS. 3 and 4 show further details of the end part of the
catheter with a multilumen needle, which is sectioned respectively
along the lines III-III and IV-IV of FIG. 2 and with parts being
visible;
[0022] FIG. 3a is a variation of embodiment of the straight
needle;
[0023] FIGS. 5 and 6 are cross sections through the multilumen
needle along the lines V-V and VI-VI of FIG. 3, respectively;
[0024] FIG. 7 shows, longitudinally sectioned, the end part of a
multilumen catheter, with the multilumen needle system being formed
by two single-lumen and straight needles arranged alongside each
other;
[0025] FIGS. 8 and 9 show possible cross sections through the
needles of the needle system according to FIG. 7, sectioned along
the line VIII-VIII;
[0026] FIG. 10 shows, cross sectioned and with parts visible, a
needle system formed by two straight and coaxial needles;
[0027] FIGS. 11 and 12 show details of the needle system according
to FIG. 10, sectioned along the lines XI-XI and XII-XII,
respectively;
[0028] FIG. 13 shows, cross sectioned and with parts visible, a
needle system formed by two helical needles arranged alongside each
other;
[0029] FIG. 14 shows, cross sectioned and with parts visible, a
needle system formed by two straight needles coaxial with each
other and of different length and with the projecting needle
portion having a helical shape;
[0030] FIGS. 15 and 16 show, cross sectioned and with parts
visible, further needle systems formed by a straight axial needle
circumscribed by a helical needle which may be, respectively,
projecting or retracted with respect to the said axial needle.
DETAILED DESCRIPTION OF THE INVENTION
[0031] In FIGS. 1 and 2 the numeral 1 designates schematically a
catheter guide of the known type which is pre-formed or steerable
and which is inserted into the blood circulation which leads to the
left ventricle of the heart and inside which the catheter system in
question is then inserted, said catheter system comprising a
catheter 2 which has a suitable length and cross section and is
made of any material suitable for this purpose, for example
Polyimide, and is provided internally with a meshwork braiding 102
and/or other suitable means (see also FIG. 3) which allow a
twisting torque to be applied to the said catheter, without the
latter being deformed, such that a rotation applied to the front
end of the catheter results in an identical rotation of the
terminal end of this catheter. The catheter 2 is provided
internally with several longitudinal lumina, for example a pair of
main and opposite lumina 3 and 4, for example having a cross
section in the form of a circle segment, and has between said
lumina, in a symmetrical arrangement, arranged alongside each other
and aligned along the diametral plane of the catheter, three
secondary lumina 5, 6 and 7, for example with a round cross
section, one of which is located preferably coaxially in the
catheter, for receiving the guide spindle 8 which is of the type
usually used for operating traditional pacing catheters.
[0032] A multilumen needle system is fixed onto the terminal end of
the catheter 2 by means of a special insert 12, in a position of
longitudinal alignment with the said catheter, said needle system
being formed by a needle which may be straight as indicated by 9'
in FIG. 3a or may preferably have a cylindrical helical shape, as
indicated for example by 9 in FIGS. 3 and 4. It is understood that
the scope of the invention also includes helical needles other than
that illustrated, for example which are of the straight type and
have one or more external helices, for example similar to wood
screws. From FIG. 5 it can be seen that the needle has two
longitudinal lumina 10 and 11 which are arranged closely alongside
each other and divided by a common wall 309 over the whole length
of the body of this needle. The base of the needle has a
fork-shaped configuration and the corresponding branches 109 and
209, which form a continuation of the respective lumina 10 and 11
of the said needle, are engaged in the corresponding lumina 3 and 4
of the catheter.
[0033] Both in the case of FIG. 3 and in the case of FIG. 3a, the
internal lumina of the needle are provided with respective lateral
discharge openings, one of which is indicated by 110 and is located
at a short distance from the needle tip, while the other one
indicated by 111 is located further upstream, in the middle part or
at the base of the said needle (see also FIG. 6).
[0034] The terminal end of the catheter is provided with a
retractable device, which is useful as an end-of-travel stop, for
stopping penetration of the needle 9 or 9' into the wall of the
myocardium which has to be treated. For this purpose it may be
possible to use a torus-shaped balloon 13 which is made of
impermeable and flexible material and which is fixed laterally onto
the terminal end of the catheter 2 and has at least one internal
duct 113 which passes through the insert 12 and is designed to
engage into one of the secondary lumina of the catheter, for
example into the lumen 6 (FIG. 2).
[0035] From FIG. 4 it can be seen that the end of an electrical
conductor 14 which runs along the whole length of the catheter and
is housed inside one of the secondary lumina, for example the lumen
7 in FIG. 2, is connected to the body of the needle 9 or 9',
together with an optional additional electrical conductor 15
connected to an optional ring 16 which is made of electrically
conducting material and is fixed on the outside of the terminal end
of the catheter and is useful as a reference electrode for the
various operations where the needle acts as a conductor of
electrical impulses. The conductors 14 and 15 are suitably
insulated from each other. If the braiding 102 of the catheter is
made of an electrically conducting material, it may replace either
one of the said electrical conductors 14 or 15. It is understood
that the function of reference electrode may be performed by means
other than the ring 16 mentioned above, for example using solutions
known in the sector of cardiac electro-stimulation.
[0036] From FIG. 1 it can be seen that the initial section of the
catheter passes through the body of a distributor 17 with respect
to which the said catheter may rotate, but not move axially, for
example owing to the presence of end stops 18 and 19. The knob 20
by means of which a rotation may be imparted to the said catheter
is fixed onto the front end of the catheter, whereas, with regard
to that stated above, the distributor 17 may remain at a
standstill. The front ends of the electrical conductors 14 and 15
are connected to small electrically conducting rings 21 and 22
which are fixed externally to different points of the catheter
body, are insulated with respect to each other and with which
brushes 23 and 24 of the distributor 17 co-operate, said brushes
being in turn connected via respective conductors to a composite,
external, fixed apparatus 25, which will be described in greater
detail below.
[0037] The lumina 3, 4 and 6 of the catheter are closed at the
outer front end and are provided along the section which passes
through the distributor 17 with respective radial openings which
are situated at mutually distant points of the catheter and lead
into respective annular chambers 26, 27 and 28 of said distributor
and which are insulated from each other and from the exterior by
annular sealing gaskets 29, 30, 31 and 32. These chambers lead to
cable connectors 33, 34 and 35 to which flexible pipes 36, 37, 38
may be connected, said flexible pipes being provided at the other
end with Luer connectors to which syringes 39, 40, 41 may be
connected, the first thereof being useful, for example, for
injecting or drawing liquid into/from the balloon 13, i.e. for
filling it and activating it as shown in FIG. 4 or for reducing it
into the collapsed condition as shown in FIG. 3, while the syringe
40 is useful for example for injecting tracer liquid which will
emerge, for example, from the opening 111 of the needle 9 or 9',
and the syringe 41 is used, for example, for injecting DNA plasmids
which for example will be discharged from the end opening 110 of
the said needle.
[0038] The catheter system as described functions and is used in
the following manner. After positioning the catheter guide 1 in the
patient, the catheter 2 is inserted inside said guide by means of
the special guide spindle 8. The end balloon 13 is in the collapsed
condition. After insertion of the catheter, the balloon 13 is
activated by means of the syringe 39 and, by means of the external
knob 20, the catheter itself is rotated in the direction for
screwing of the helical needle 9 into the myocardium, until this
needle has been completely screwed in. The correct position of the
needle may be verified from the outside by means of the apparatus
25 which detects, for example, a bioelectrical impedance and/or
ECG, using the electrical conductor 14 connected to the needle and
the conductor 15 connected to the annular reference electrode 16.
In order to improve the results of this test, the needle 9 or 9'
may be advantageously lined with a thin layer of electrically
insulating material, for example, Parylene, over practically the
whole length, as schematically indicated by the broken lines and by
45 in FIGS. 3a and 4, except for an appropriate tip portion which
remains electrically conducting.
[0039] Once screwing of the needle into the myocardium has been
performed, via the syringe 40, a correct quantity of tracer is
injected into this wall and, if the needle is correctly inserted,
remains for a relatively long period of time in the said wall and
may be easily detected by external image diagnostics systems of the
known type, in the form of a persistent spherical-shaped mark.
Should the needle not be correctly inserted into the myocardium,
the injected tracer would become dispersed in the blood stream. The
injected tracer may for example be of the type which is useful for
detection by means of X-rays or using ultrasound image or magnetic
nuclear resonance systems. If a dual-lumen needle as shown in FIGS.
3 and 3a is used, the tracer fluid is preferably discharged from
the orifice 111 of the needle itself since, if it is subsequently
established using the abovementioned procedure that the needle is
correctly inserted in the myocardium, there is the absolute
certainty that the other discharge orifice 110, intended for the
discharge of therapeutic fluid, is also correctly inserted into the
myocardium itself.
[0040] After verifying and documenting with appropriate means that
the needle has been correctly inserted, DNA plasmids are injected
into the myocardium via the syringe 41. In order to reinforce the
transfer of the abovementioned plasmids into the cells of the
cardiac tissue, the external apparatus 25 may be arranged so as to
transmit into the tissue itself, via the electrical circuit
connected to the needle 9, electrical impulses which have suitable
characteristics and are synchronized with the beat R of the
spontaneous activity of the heart. Again for this purpose, the
external apparatus 25 may be designed to generate ultrasounds which
are conveyed to the needle 9 and therefore to the perfused zone of
the myocardium, via a conductor with suitable characteristics,
which is indicated schematically in FIG. 1 by 42 and which is for
example connected to the needle via the axial lumen 5, after
removal of the guide spindle 8. It is understood that the catheter
may have a secondary lumen specifically designed to contain an
ultrasound conductor connected to the needle 9 or 9'.
[0041] With reference to FIGS. 7 to 16, variations of embodiment of
the needle system mounted on the catheter will now be described,
said catheter, unlike the one previously considered, being composed
of two single-lumen needles. The catheter 2 illustrated in FIG. 7
is identical to the multilumen catheter illustrated in FIG. 1 and
its lumina 3 and 4, which are respectively connected to the
external systems for injection of the therapeutic fluid and the
tracer fluid, are joined to the end sections 109, 209 of respective
straight and single-lumen needles 9'a and 9'b which are preferably
of different length, preferably arranged in axial alignment with
the catheter and preferably fixed together by means of welds 43, as
can be seen from FIG. 8. 10 and 11 indicate the lumina of the
needles which terminate in respective openings 110, 111 for
discharging the fluids conveyed by said lumina. The tip of the
shorter needle is preferably shaped in the manner of a flute
mouth-piece and is suitably connected to the side surface of the
adjacent needle in order to facilitate penetration, into the
myocardium, of the needle system 9' thus formed. FIG. 9 illustrates
a variation according to which the needles 9'a and 9'b have a
flattened--for example semi-circular--cross section so that the
needle system 9' formed by them can be made to assume a
substantially round cross section.
[0042] In the solution according to FIGS. 10, 11 and 12, again
relating to a needle system 9' of the straight type, the longer
needle 9'a is partly inside and coaxial with the shorter needle
9'b, the end part of which is closed, converging onto the needle
9'a, and may be provided with several lateral openings 111 for
discharging the tracer fluid. The needle 9'a emerges in a sealed
manner from the needle 9'b at the start of the bifurcation which
forms the end sections 109 and 209 for connection to the lumina 3
and 4 of the catheter.
[0043] The solution according to FIG. 13 is equivalent to that of
FIG. 7, but envisages a needle system 9 which is formed by two
helical needles 9a and 9b which are arranged alongside each other
and preferably fixed by means of welding and which extend around
the axis of the catheter 2. The comments made with reference to
FIGS. 8 and 9 for the solution of FIG. 7 are also applicable here.
The needles enter preferably into the catheter being closely
arranged around its axis and then diverge away from each other and
engage into the lumina 3, 4 with the end sections 109, 209. It is
understood that the scope of the invention also includes the
variant, not shown, whereby the helical needles 9a and 9b are
staggered and distant from each other, with the tip of the shorter
needle being distant from the body of the longer needle. In this
case the needles may enter into the catheter with sections which
are distant from the axis of the said catheter.
[0044] The solution according to FIG. 14 is derived from that of
FIG. 10 and envisages a needle system 9 formed by a short needle
9'b of the straight type from which a needle 9a terminating in a
helical shape projects coaxially.
[0045] The solution according to FIG. 15 illustrates a needle
system 9 formed by a straight short needle 9'b which is aligned
axially with the catheter and by a long helically shaped needle 9a
which extends concentrically around the said central needle
9'b.
[0046] The solution according to FIG. 16 is a variation of the
solution according to FIG. 15 and envisages a needle system 9
formed by a long straight central needle 9'a and by a helically
shaped external needle 9b which extends concentrically around the
said central needle. This solution could be preferred to that of
FIG. 15 since the straight central needle 9'a is inserted firstly
into the myocardium and acts as a centring element and a rotational
pivot for the helical needle 9b. In both solutions according to
FIGS. 15 and 16, the helical needle is able to enter into the
catheter with an arrangement close to the straight needle, as
illustrated by continuous lines, or is able to enter into the
catheter with an arrangement offset from the axis of the straight
central needle, as indicated by A and B, in order to favour, if
necessary, automatic stopping of the screwing action of the needle
system.
[0047] In FIGS. 7 to 16, 44 denotes in broken lines the location,
if necessary, on the terminal end, of the catheter, of an
ultrasound generator which is integral with the base of one or both
needles and connected to an electrical supply circuit, not shown,
which passes through a secondary longitudinal lumen of the catheter
for connection to an external power supply unit. With this solution
it is possible to transmit to the needle system, and therefore to
the perfused zone of the myocardium, the ultrasounds which are
necessary for reinforcing the transfer of the therapeutic fluid
into the cells of the myocardium tissue. It is understood that the
same comments made in respect of the preceding solutions are
applicable to the variations according to FIGS. 7 to 16, with
regard to the possibility of electrical connection of the needle
system to external apparatus and partial insulation of the said
needle system, except for a suitable section of its terminal part,
using electrical insulation material, for example based on
"Parylene". The catheter will also be provided on the terminal end
with the electrically conducting ring 16 having the function of a
reference electrode for all the operations which the needle system
performs as a conductor of electrical impulses. The catheter will
also be provided with the internal anti-twisting braiding 102 and
on the terminal end of the said catheter the already mentioned
retractable device 13, with external activation and deactivation
controls, for stopping penetration of the needle system into the
myocardium will be provided.
[0048] It is understood that the dimensions and the proportions
indicated in the drawings are purely exemplary and do not limit the
scope of the invention. Purely by way of a non-limiting example,
some dimensional characteristics for the construction of the
apparatus according to the invention are now described. The
catheter 2 may, for example, have an external diameter of about 7
French, that is to say about 2.1 mm, while the external diameter of
the helix of the needle system with at least one helical needle,
may for example be about 2 mm. The projecting part of the longer
needle must not, for example, exceed the length of about 5 mm,
while the projecting part of the shorter needle will have for
example a length of about 2.5-3 mm. The needles which form the
needle system may for example each have an external diameter of
about 0.30 mm.
* * * * *