U.S. patent application number 10/082074 was filed with the patent office on 2003-08-28 for retrograde cannula having manually retractable sealing member.
Invention is credited to Gershowitz, Arthur D..
Application Number | 20030163114 10/082074 |
Document ID | / |
Family ID | 27753028 |
Filed Date | 2003-08-28 |
United States Patent
Application |
20030163114 |
Kind Code |
A1 |
Gershowitz, Arthur D. |
August 28, 2003 |
Retrograde cannula having manually retractable sealing member
Abstract
A retrograde cannula includes coaxial inner and outer bodies,
wherein a least of the portion of the inner body is axially
slidable within the outer body. The inner body forms an infusion
lumen for conducting CPG. A sealing member is mounted adjacent a
distal end of the outer body and is expandable into sealing
relationship with a wall of a patient's heart. The sealing member
includes proximal and distal ends that are moved away from one
another to collapse the sealing member in response to axial sliding
of the inner body within the outer body to reduce a profile of the
cannula, and thereby facilitate movement of the cannula through a
patient's body.
Inventors: |
Gershowitz, Arthur D.; (Ann
Arbor, MI) |
Correspondence
Address: |
Platon N. Mandros, Esq.
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
27753028 |
Appl. No.: |
10/082074 |
Filed: |
February 26, 2002 |
Current U.S.
Class: |
604/509 ;
604/96.01 |
Current CPC
Class: |
A61M 2025/0004 20130101;
A61M 2025/1052 20130101; A61M 25/10 20130101 |
Class at
Publication: |
604/509 ;
604/96.01 |
International
Class: |
A61M 031/00 |
Claims
What is claimed is:
1. A retrograde cannula for delivering fluid to a patient's vessel,
the cannula comprising: a body arrangement defining a longitudinal
axis and including coaxial inner and outer bodies, at least a
portion of the inner body being axially slidable within the outer
body, the inner body forming an infusion lumen extending between
proximal and distal ends of the inner body for conducting fluid,
the infusion lumen including at least one outlet adjacent the
distal end of the inner body thereof for discharging the fluid; and
a sealing member disposed on the body arrangement adjacent a distal
end of the outer body and being expandible into sealing
relationship with the vessel, the sealing member including proximal
and distal ends that are moved away from another to collapse the
sealing member in response to axial sliding of the inner body
within the outer body to reduce a profile of the cannula.
2. The cannula according to claim 1 wherein the proximal end of the
sealing member is connected to the outer body, the distal end of
the sealing member arranged to be displaced forwardly by the inner
body in response to axial sliding of the inner body within the
outer body.
3. The cannula according to claim 2 wherein the distal end of the
sealing member is affixed to the inner body.
4. The cannula according to claim 3 wherein the sealing member
comprises an inflatable balloon, the inner body including
communication passages for communicating the infusion lumen with
the interior of the balloon.
5. The cannula according to claim 2 wherein the outer body includes
a bulbous portion defined by convexly projecting ribs spaced
circumferentially apart; the sealing member arranged to surround
the bulbous portion; the proximal and distal ends of the sealing
member affixed to the outer body with the enlargement disposed
between the proximal and distal ends of the sealing member; a
distal portion of the inner body affixed to a distal portion of the
outer body at a location distally of the bulbous portion; the ribs
being collapsible to a smaller profile in response to axial sliding
of the inner body and simultaneous axial displacement of the distal
portion of the outer body.
6. The cannula according to claim 5 wherein the sealing member
comprises an inflatable balloon, the infusion lumen communicating
with an interior of the balloon through spaces formed between
adjacent ribs.
7. The cannula according to claim 2 wherein the sealing member is
elastic and normally assumes an expanded state; an interior of the
sealing member communicating with the infusion lumen for receiving
fluid therefrom; the sealing member including holes for discharging
fluid received from the infusion lumen; the inner body being
engageable with the distal end of the sealing member in response to
axial sliding of the inner body within the outer body to collapse
the sealing member to a smaller profile.
8. The cannula according to claim 1 further including holding means
for holding the inner and outer bodies in selected longitudinal
relationship.
9. The cannula according to claim 8 wherein the holding means
comprises a pin-and-slot connection between the inner and outer
bodies, the slot including notches for receiving the pin.
10. A method of inserting a retrograde cannula into a vessel of a
patient's body, the cannula comprising a body arrangement including
coaxial inner and outer bodies, the inner body being axially
slidable within the outer body, the inner body forming an infusion
lumen extending between proximal and distal ends of the inner body
for conducting pressurized fluid, the inner body including an
outlet adjacent the distal end thereof for discharging the fluid,
and a sealing member disposed on the body arrangement adjacent a
distal end of the outer body and being expandible into sealing
relationship with the vessel, the sealing member having proximal
and distal ends that are moved away from one another to collapse
the sealing member in response to axial sliding of the inner body
within the outer body to reduce a profile of the cannula, the
method comprising the steps of: A) axially sliding the inner body
within the outer body in a first direction to move the proximal and
distal ends of the sealing member away from one another for
collapsing the sealing member to a smaller profile; B) inserting
the reduced-profile cannula into the vessel; and C) axially sliding
the inner body within the outer body in a second direction to move
the proximal and distal ends of the sealing member toward one
another for permitting the sealing member to expand outwardly.
11. The method according to claim 10 wherein the proximal end of
the sealing member is affixed to the outer body, the distal portion
of the sealing member being affixed to the inner body, wherein
axially forward sliding of the inner body moves the distal end of
the balloon forwardly relative to the proximal end thereof.
12. The method according to claim 11 wherein the sealing member
comprises an inflatable balloon, and further comprising the step of
conducting fluid through the infusion lumen for inflating the
balloon subsequent to step C.
13. The method according to claim 10 wherein the outer body
includes a collapsible bulbous portion disposed axially between the
proximal and distal ends of the sealing member; the inner and outer
bodies being affixed together at a location distally of the bulbous
portion; wherein step A comprises displacing distal portions of the
inner and outer bodies together relative to a proximal portion of
the outer body for collapsing the bulbous portion.
14. The method according to claim 10 wherein the proximal end of
the sealing member is affixed to the outer body, step A comprising
moving the inner body into contact with a distal end of the sealing
member to collapse the sealing member.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to retrograde cannulas, and in
particular to retrograde cannulas used in the delivery of
cardioplegia and having automatically expandable sealing
members.
[0002] Retrograde cannulas are commonly employed during certain
cardiac surgical procedures, in order to deliver cardioplegia into
coronary veins to effect cardiac arrest by depolarizing cell
membranes.
[0003] In order to occlude the coronary sinus, the distal end of
the cannula includes a sealing member such as an expandible balloon
adapted to seal against a wall of the coronary sinus. Balloons may
be of the manual-inflating or auto-inflating type. In the
auto-inflating type (also referred to as self-inflating), the
balloon is in fluid communication with the CPG being delivered to
the blood stream and is inflated thereby.
[0004] In manual-inflating cannulas, fluid for inflating the
balloon is added or withdrawn by means of a syringe. When the
balloon of a manual-inflating cannula is deflated, it is common for
the balloon to retract snugly against the cannula body when not
inflated, whereby the cannula has a reduced profile to facilitate
insertion and removal into the body.
[0005] In contrast, auto-inflate retrograde catheters typically
include a balloon having a relatively permanent shape which varies
little between the inflated and deflated states. The inflation of
the balloon mainly serves to make the balloon more rigid or turgid,
i.e., more less pliant. Thus, the profile of the cannula is not
appreciably reduced when the balloon is deflated. This can lead to
problems when attempting to insert the cannula into a patient's
vessel.
[0006] It has previously been proposed in U.S. Pat. No. 5,197,952
to stretch a cannula prior to insertion thereof into a patient.
That involves the fixing of a plug within the infusion lumen in the
area of the balloon. The plug forms a barrier against which a
stylet can be pushed in order to stretch the cannula. The balloon
is provided with a fluid inlet disposed proximally of the plug and
a fluid outlet disposed distally of the plug, in order to enable
fluid (e.g., CPG) to flow through the balloon (and around the plug)
after the cannula has been installed. It will be appreciated that
the need to install a plug complicates the manufacture and use of
the cannula.
[0007] It would be desirable to provide an auto-inflate cannula
with the ability to significantly reduce its profile and thereby
facilitate insertion and removal of the cannula. It would be
advantageous to accomplish this without the need to provide a
barrier within the cannula body and/or without having to provide an
appreciable restriction to the flow of infusion liquid.
SUMMARY OF THE INVENTION
[0008] The present invention relates to a retrograde cannula for
delivering fluid to a patient's vessel. The cannula comprises a
body arrangement which defines a longitudinal axis. The body
arrangement includes coaxial inner and outer bodies. At least a
portion of the inner body is axially slidable within the outer
body. The inner body forms an infusion lumen extending between
proximal and distal ends of the inner body for conducting fluid.
The infusion lumen includes an outlet adjacent the distal end of
the inner body for discharging the fluid. The cannula also includes
a sealing member disposed on the body arrangement adjacent a distal
end of the outer body. The sealing member is expandable into
sealing relationship with the vessel. The sealing member includes
proximal and distal ends that are moved away from one other to
collapse the sealing member in response to axial sliding of the
inner body within the outer body to reduce a profile of the
cannula.
[0009] The present invention also relates to a method of inserting
the retrograde cannula into a vessel of a patient's body. The
method comprises the steps of:
[0010] A) axially sliding the inner body within the outer body in a
first direction to move the proximal and distal ends of the sealing
member in opposite directions for collapsing the sealing member to
a smaller profile;
[0011] B) inserting the reduced-profile cannula into the vessel;
and
[0012] C) axially sliding the inner body within the outer body in a
second direction to move the proximal and distal ends of the
sealing member toward one another for permitting the sealing member
to extend outwardly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The objects and advantages of the invention will become
apparent from the following detailed description of preferred
embodiments thereof in connection with the accompanying drawings in
which like numerals designate like elements and in which:
[0014] FIG. 1 is a longitudinal sectional view taken through a
cannula according to a first embodiment of the invention, with a
sealing element thereof in a non-collapsed state.
[0015] FIG. 2 is a view similar to FIG. 1 with the sealing member
in a collapsed state.
[0016] FIG. 3 is a fragmentary side elevational view of a portion
of the cannula depicted in FIG. 1, with the sealing element
removed.
[0017] FIG. 4 is a sectional view taken along the line 4-4 in FIG.
3.
[0018] FIG. 5 is a fragmentary view of a proximal portion of the
cannula depicting a mechanism for holding inner and outer bodies of
the cannula in selected positions.
[0019] FIG. 6 is a longitudinal sectional view taken through a
cannula according to a second embodiment of the invention, with a
sealing element thereof in a non-collapsed state.
[0020] FIG. 7 is a view similar to FIG. 6 with the sealing member
in a collapsed state.
[0021] FIG. 8 is a longitudinal sectional view taken through a
cannula according to a third embodiment of the invention, with a
sealing element thereof in a non-collapsed state.
[0022] FIG. 9 is a view similar to FIG. 8 with the sealing member
in a collapsed state.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0023] Depicted in FIGS. 1-5 is a first preferred embodiment of an
auto-inflate retrograde cannula 10 according to the present
invention. The cannula 10 comprises an outer body 12 and a coaxial
inner body 14. The outer and inner bodies are formed of a plastic
material suitable for insertion into a human body, such as PVC,
urethane, or silicone for example. The outer body 12 is of
cylindrical configuration except for a ribbed portion 16 disposed
adjacent a distal end 18 of the outer body. The ribbed portion is
of generally bulbous shape and includes slits 20 of any suitable
number extending generally in the longitudinal direction of the
cannula (see FIG. 3). The slits 20 cause longitudinal ribs 22 to be
formed in the ribbed portion that are separated from one another by
the slits 20. Each rib 22 is supported solely at longitudinally
spaced ends thereof and is of curved shape such that the outer
surface 24 thereof is convex, and the inner surface 26 is
concave.
[0024] The inner body 14 is of cylindrical shape and includes an
infusion lumen 28 and a pressure monitoring lumen 30 adjacent
thereto. The infusion lumen 28 serves to conduct fluid to the
patient's vessel, e.g. to conduct cardioplegia to the heart, and
the pressure monitoring lumen 30 enables pressure to be monitored
at the distal end of the cannula. Thus, the proximal end of the
cannula can be connected to a conventional pressure indicating
device (not shown).
[0025] The lumens 28, 30 extend from the distal end to the proximal
end of the cannula and are open at their distal ends 28a, 30a.
[0026] A distal portion 32 of the inner body 14 is affixed to a
distal portion 34 of the outer portion, which distal portions 32,
34 are defined as being disposed distally of the ribbed portion 16.
The rest of the inner body 14 is slidable relative to the outer
body. Thus, by sliding the inner body 14 forwardly while holding
the outer body 12 stationary, the ribs 22 can be collapsed, or
flattened out, as shown in FIG. 2, to reduce the profile (i.e., to
reduce the maximum cross-sectional size) of the cannula.
[0027] Affixed to the outer body is an expandable sealing member 40
in the form of a balloon which encompasses the ribbed portion 16.
The balloon 40 includes distal and proximal edges 42, 44 affixed to
the outer body 12 adjacent respective sides of the ribbed portion
16.
[0028] The inner body 14 includes inflation holes 46 which
communicate the infusion lumen 28 with the balloon interior. Thus,
when fluid, such as cardioplegia, is conducted through the infusion
lumen 28 and discharged through one or more outlets at the distal
end 28a, the fluid also inflates the balloon, whereby the balloon
is inflated, i.e., becomes turgid.
[0029] In operation of the FIG. 1-5 embodiment, the cannula is
inserted into the body in the low-profile shape shown in FIG. 2,
i.e., with the inner body 14 having been slid forwardly relative to
the outer body 12 to collapse, i.e., generally flatten, the ribs 22
and the balloon 40 to a smaller profile. The term "collapse" as
used herein does not require a complete collapsing of the ribs, and
the balloon, but rather is intended to be broad enough to include a
partial collapse. Once the cannula has been inserted into a vessel
of the body, e.g. the coronary sinus, the inner body 14 is slid
rearwardly, whereby the ribs 22 assume the enlarged profile state
of FIG. 1. Preferably in this state, the ribs are able to bear
against a wall of the coronary sinus with the non-inflated balloon
sandwiched therebetween.
[0030] When fluid, such as cardioplegia, is delivered through the
infusion lumen 28, the cardioplegia flows through the inflation
holes 46 to inflate and stiffen the balloon 40 against the wall of
the coronary sinus to seal off any areas not previously sealed. The
cardioplegia is thus able to enter the heart vessel.
[0031] After an initial charge of cardioplegia has been delivered
the flow is halted. Thereupon, the balloon becomes deflated, but
the distal end of the cannula remains deployed in the coronary
sinus, because the ribs 22 continue to be pressured against a wall
of the coronary sinus. Thus, when a subsequent charge of
cardioplegia is delivered through the infusion lumen, the distal
end of the catheter is still deployed in a desired position.
[0032] To remove the cannula from the body, the inner body 14 is
slid forwardly to deform (flatten) the ribs 22 and the balloon for
reducing the profile of the cannula.
[0033] It may be desirable to provide means for holding the inner
body 14 in its various longitudinal positions, which can be done in
any of numerous ways. For example, as shown in FIG. 5, the outer
body 12 can be provided with a slot 41 having a plurality of
notches 43a, 43b, 43c, the number of notches corresponding to
respective positions of the inner body 14 relative to the outer
body 12, as desired.
[0034] The inner body 14 includes a pin 48 received in the slot.
Once the inner body 14 is moved axially to a desired position, it
can be rotated to position the pin in a respective notch to retain
the inner body in position.
[0035] Another embodiment of the invention is depicted in FIGS. 6
and 7. In That embodiment, a cannula 50 includes outer and inner
bodies 52, 54, with the entire body slidable longitudinally without
being relative to the outer body, i.e., no part of the inner body
54 is fixed to the outer body 52. The inner body 54 includes an
infusion lumen 56 and a pressure lumen 58. A balloon 60 has a
distal end 62 attached to the inner body 54 and a proximal end 64
attached to the outer body 52. Inflation holes 64 are formed in the
inner body 54 to communicate the infusion lumen 56 with the
interior of the balloon 60.
[0036] Similarly to the earlier-described embodiment, the balloon
60 can be flattened to reduce the profile of the cannula by sliding
the inner body 54 forwardly relative to the outer body 52, as shown
in FIG. 7.
[0037] The cannula 50 is inserted and removed relative to a
patient's body with the inner body 54 slid forwardly relative to
the outer body 52, i.e., with the cannula in a reduced-profile
state (see FIG. 7). Cardioplegia is delivered after the distal end
of, the cannula has been inserted into the coronary sinus and the
inner body 54 has been slid rearwardly. Thus, the balloon 60 is
able to be inflated into firm contact with the wall of the coronary
sinus by the cardioplegia being delivered.
[0038] It will be appreciated that the embodiment according to
FIGS. 6 and 7 enables the profile of the cannula to be reduced,
like the embodiment according to FIGS. 1-4. If desired, a
pin-and-slot arrangement 41, 48 similar to that of FIG. 5 can be
employed in order to retain the inner and outer bodies 54, 52 in
their relative longitudinal positions.
[0039] A third embodiment of the invention is depicted in FIGS. 8
and 9. Depicted therein is a cannula 70 having outer and inner
bodies 72, 74. The inner body 74 is longitudinally slidable
relative to the outer body 72, and no part of the inner body 74 is
fixed to the outer body. The inner body 74 includes a infusion
lumen 76 and a pressure lumen 78. Attached to a distal end of the
outer body 72 is the proximal end of a flexible (preferably
elastic) expandable sealing member 80 which is not in the form of
an inflatable balloon, but rather has a permanent relaxed (normal)
shape shown in FIG. 8. The sealing member includes holes 82
adjacent a distal end for discharging cardioplegia, as will be
explained. When inserting or removing the cannula 70 relative to a
patient's body, the profile of the cannula is reduced by
longitudinally extending the inner body 74 forwardly relative to
the outer body 72 and into contact with the sealing member 80 to
longitudinally extend and collapse the sealing member 80 as shown
in FIG. 9. During installation into the patient's body, once the
sealing member has reached the desired location in the coronary
sinus, the inner body 74 is retracted (i.e., moved to the right in
FIGS. 8-9), to return the sealing member 80 to its normal (i.e.,
expanded) shape and into sealing relationship with the wall of the
coronary sinus. Cardioplegia can then be conducted through the
infusion lumen 76 and into the sealing member. The cardioplegia
exits the sealing member through the holes 82 formed in the sealing
member.
[0040] It will be appreciated that due to the presence of the holes
82 in the sealing member, the pressurized cardioplegia does not
function to inflate the sealing member 80. Rather, the sealing
member 80 remains in expanded sealing relationship with the wall of
the coronary sinus whenever the inner body 74 is retracted away
from the sealing member.
[0041] Advantageously, it is possibly to administer an antegrade
cardioplegia through an antegrade cannula (not shown) with the
sealing member 80 of the retrograde cannula disposed in sealing
relationship with the wall of the coronary sinus. In that regard,
the outer body 72 is provided with holes 90 that are normally
blocked by the inner body 74. However, by retracting the inner body
(i.e., to the right in FIGS. 8-9) sufficiently for to expose the
holes 90, wherein the distal end of the inner body travels to the
right of the holes 90, the holes will be exposed, so that the
antegrade cardioplegia can flow through the retrograde cannula from
left-to-right by entering the sealing member 80 via its holes 82,
and then flowing through the outer body 72 and finally exiting
through the holes 90.
[0042] It will be appreciated that the present invention provides a
retrograde cannula whose profile can be appreciably reduced in
order to facilitate the insertion and removal of the cannula,
without having to install a plug within the infusion lumen.
[0043] Although the present invention has been described in
connection with a preferred embodiments thereof, it will be
appreciated by those skilled in the art that additions, deletions,
modifications, and substitutions not specifically described may be
made without departing from the spirit and scope of the invention
as defined in the appended claims.
* * * * *