Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Div. II~
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~l T~ERAPEUTIC METHOD OF USE FOR MINIATURE DETACHABI.E
-j' BALLOON CATHETER _
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,,BACKGROUND OF T~E IMVENTION
¦, The development of niniature balloon catheters for use
l¦in small tortuous locations such as neurological blood ~essels
liis an extremely active and dynamic field. The development can
! be traced through the work of Dr. Serbinenko of Russia
I as published in the Journal of ~eurosurgery, Volume 41, August
¦ 1974, pages 1~5-1~5 and entitled Balloon Catherization and
¦!Occlusion of Ma~or Cerebral Vessels. An example of more
¦ recent work in the area is present in U. S. Patent ~lo. 4/085,757
issued to Dr. Paul H. Pevsner on April ~5, 1978.
i The rapid development of the art is readily apparent
~land t~e visible ield of use becomes greater as experimental
';work continues within the medical profession. A variety of
improved designs for miniature balloon catheters ~or detachment,
~erfusion and Other purposes are being developed at rapia rate
¦with improvements ~eing conceived constantly. ~aturally
!proceeding hand-in-hand with the improved aevices is a sequence
lof improved technigues in the use of balloon catheters both for
¦neurological purposes and for use in other body vessels and
¦lcavities.
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Original developments in the use of detachable perfusio~,
I balloons were primarily directed toward the aiagnosis and treat- !
¦! ment of neurological diseases; In certain instances larger
¦ non-detachable balloons ha~e been utilized for emergency pre-
! operative control of hemmorrhage in the abdominal circulation,
¦¦ ~ut most ef~orts have centered aoout therapeutic embolization
¦l with a variety of materials.
¦¦ . One particular area open for development is in the use
j of the detachable balloon occlusion as offering a method for
Iprecise and possibly long-term occlusion without ~he dangers
I of inadvertent embolization associated with the injection of
¦particulate matter through a catheter. There is very little
data available-describing the possible ~ariables influencing
¦balloon occlusion. .
IiS~RY OF THE INVENTION
With the above background in mind, it is among the
;'primary objective~ of the present invention to present a
¦technique for use of detachable balloons for therapeutic emboliza-
tion. The objective is accomplished by the consideration of the
osmolarity of radiopaque media used to fill the balloon. ~
escription of the development of the present invent;on ~ppears
in Radiology, Volume 126, No. 2, pages 521-523, publi~hed ~n
!February 1978 and entitled Therapeutic Em~olization With
¦1 ~etachabl Da1;L~o=s.
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Thus this divisional application provides a
balloon catheter comprising; a l-esi'ient cannula adapted
for attachment to a first fluid source and insertable
into a vessel containing a second fluid, an inflatable
balloon detachably mounted on the end of the cannula in
fluid communication therewith, detachment means to separate
the balloon from the cannula after the balloon has been
inflated by fluid from the first fluid source to fix the
balloon in position in the vessel with the first fluid
having an osmolarity substantially the same as the second
fluid in the vessel and being a contrast agent, and sealing
means to seal the inflated balloon after the cannula is
detached to retain the balloon in inflated condition in the
vessel for an extended period of time to create a vessel
occlusion.
In another embodiment the present invention
provides an inflatable balloon adapted to be inserted
in a fluid containing vessel to create a vessel occlusion
for an extended period of time comprising a balloon member
having a sealable opening therein through which a second
fluid from a fluid source can be introduced to inflate the
balloon to fix the balloon in position in a vessel
whereupon sealing of the sealable opening in the balloon
will retain the balloon in inflated condition in the vessel,
the second fluid from the fluid source having an osmolarity
substantially the same as the fluid in the vessel and being
a contrast agent to create a vessel occlusion for an extended
period of time.
As pointed out in the above publication dealing with the
sub~ect matter of the present invention, osmolarity of the dis-
tending contrast media is an important variable influencing
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the permanency of balloon occlusion, particularly where the
balloon is of a semi-permeable material such as a silicone
membrane commonly known as SILASTIC rubber. It is an objective to ~se
a fluid to produce the desired conditions for long term
embolizations.
- In utilizing a semi-permeable membrane material such as a
silicone material for the expandable balloon, for example a
STL~ IC rubber balloon, the following compounds have been found
effective to produce the desired osmolarity conditions particular-
ly for radiopaque contrast media. A first is R-60 manufactured
by Squibb, Inc., Princeton, New Jersey 08540 containing 60% Na-
meglamine diatrizoate dilu,ed to a 30 percent iodine con-
centration and identified as R-30. A second is METRIZAMIDE, a
non-ionic, fluid contrast medium manufactu-ed by Sterling-
Winthrop Research Institute of Rensselaer, New York 12144. A
third is Iodipamide Meglumine manufactured by Squibb, Inc.,
l Princeton, New ~ersey 08540 currently available for intro-
¦ vascular use and nearly iso-osmotic ~hen diluted by 30% with
l sterile water.
¦ It is contemplated that in dealing with a silicone
¦ balloon as the detachable member, it acts as a semi-permeable
¦ membrane and permanency of the detached balloon inflation is
¦ dependent on the osmolarity of the filling substance within the
¦ volume limits of the aetachable balloon.
¦ In order to prevent premature or undue swelling and
¦ rupturing as well as loss of radiopacacity of the ball~on implant ,
¦ a radiopaque filler of similar osmolarity to blood is used. As
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a result, the longevity ~f the balloon is increased and a more
effective and better the'ra~eutic embolization is achieved.
In summary, a therapeutic medical procedure is provided
utilizin~ a miniature balloon c:atheter of the type including a
resilient cannula adapted for attachment to a source of fluid
and having a small outer diamet:er for insertion into small
vessels containing fluid. An inflatable balloon having a mouth
at the proximal end thereof is detachably mounted on the end of
the cannula in fluid communication therewith. Sealing means is
on t'he catheter to close the mouth of the balloon when the
cannula is ~etached therefrom. ~he procedure involves inserting
the balloon catheter into a small vessel. The catheter is
advanced in the vessel to the desired location. The balloon
Qtheter is attached to a source of fluid having an osmolarity substantially
tne same as the fluid in the vessel and being a contrast agent, and the
balloon is inflated with the fluid from the fluid source
traveling through the cannula until the balloon is fixed in
position in the vesselO The cannula is then detachel from the
b'alloon and removed from the vessel. The sealing means seals
the mouth of the inflated balloon with the fluid therein to main-
tain the balloon in inflated position for an extended period of
time to create a vessel ~ccluslon. I
In another embodiment, the invent;on pr~vi~des A ba11Oon
catheter assembly for use in a medical procedure which produces
embolization of a fluid-containing vessel comprising:
a resilient cannula having a proximal po~tion adaptecl for
connection to a source of external fluid, said cannula having an
outer diameter adapted for insertion into said fluid~containing
vessel;
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an inflatable balloon member detachably connected by a
fluid-tight sealing arrangement to a distal portion of said
cannula, the interior of said balloon being in fluid
communication with said cannula for the reception of said
external fluid therein for inflating said balloon member
inside said vessel, said balloon member including an
- inflatable portion made of an expandable semi-permeable
material;
a source of external fluid in sufficient quantity to
inflate said balloon member inside said vessel to cause
embolization of said vessel, said external fluid having its
osmolarity property substantially the same as the osmolarrity
of the fluid in the vessel and being a contrast agent; and
means for delivering said external fluid to said balloon
member to effectuate its inflation, whereby after said balloon
member is detached inside said vess~l it is adapted to remain
inflated for long-term embolization of said vessel.
With the above objectives among others in mind,
reference is made to the attached drawings.
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BRIEF DESCRIPTION OF THE l)RAl~INGS
In The Drawings.
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Figure 1 is a fragmentary sectional view of the
. catheter utilized in performing the medical procedure of the
5 . invention;
. Figure ~ is a fragmentary sectional view of the
. catheter inserted into a small ve~sel and partially expan~ed
by introduction of fluid so that the catheter is floated
. along with the liquid in the vessel to the desired location;
lD Figure 3 is a fragmentary sectional view thereof -
with the balloon having been expanded to seal against the
walls of the vessel;
Figure 4 is a fragmentary sectional view thereof
with fluid being introduced to detach the balloon from the
cannula;
Figure 5 is a fragmentary sectional view thereof with
' the cannula detached from,the balloon and being removed
therefro~ and the balloon sealed;
, . , Figure 6 is a fragmentary sectional view thereof with
t,he cannula having been removed from the balloon and the
balloon being retained in sealed expanded position in the
vessel with fluid therein to create a vessel occlusion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The miniature balloon catheter assembly 20 adaptable
for use in the medical technique of the present invention ~s
. shown in the dra~7ings.
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. It includes a hollow cannula 22 of polyurethane material
. or any conventional substitute therefor. One end of cannula 22
is adapted to be connected to a source of fluid in a conventional
. manner. Mounted in the other end of cannula 22 is an enlarged
end 24 of a pin 26. The enlarged end 24 expands the end portion
28 of the cannula so that a frictional fit is presented there-
between. The pin has a passageway 30 therethrough and a side .
opening 32 adjacent the wider diameter portion 24. The smaller
. end of the pin 30 is positioned within a self-sealing plug 34
mounted in the open end portion 3fi of an expandable balloon 38.
The balloon 38 can be formed of a conventional material such
as a semi-permeable membrane of silicone commonly known ~s
SILASTIC rubber. The end portion 36 of balloon 38 terminates in an
. open mouth 40. The mouth 40 is expanded to frictionally seat
- on the outer surface of expanded end portion 28 of cannula 22.
The end of pin 30 extends through plug 34 so that the opening 42
~at its forward end is in communication with the hollow interior
44 of the balloon 38. The passageway 30 through the pin 26
communicates with the hollow interior of cannula 22 and with the
interior of balloon 44 thereby providing a passageway for fluid
. into the balloon.
Surrounding the portion of the balloon where the plug
34 is locatecl on the exterior surface thereof is an elastic
band 46 of plastic or rubber ~aterial which assists in
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retaining the pin in the self-sealing plug and is utilized
to assist with the self-sealing plug in sealing the open
end of the balloon when the cannula and pin combination
is r~moved therefrom during detachment. A secondary small
chamber 48 between the end of the cannula 22 and the self-
sealing plug 34 communicates with side opening 32 and provides
the area for additional fluid utilized to expand end portion
36 of the balloon and facilitzte withdrawal of the cannula and
pin therefrom during detachment.
The self-sealing plug 34 can be formed of any commonly
~sed self-sealing plastic or natural or synthetic rubber material.
Similarly, the pin 26 can be formed of a rigid plastic or a
metal substitute therefor.
In the steps of use, the catheter 20 is introduced
to the vessel. An introductory catheter is inserted
through the body into the vessel to provide a passageway for
catheter 20 and then the catheter is passed through the in-
troduciny catheter until it is positioned within the vessel 50
as shown in Figure 2. The vessel 50 is ~illed with 2 fluid such
as blood 52 traveling in the direction shown by the arrow in
Figure 2. Radiopaque contrast media in the form of a fluid
having an osmolarity substantially the same as blood is then
introduced from a conventional fluid source into the hollow
interior of cannula 22 and accordinyly thxough the passageway 30
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¦ in the pin 26 and into the hollow chamber 44 of ballo~n 38.
¦ Sufficient fluia is introduced to partially expand the balloon
~ and facilitate its natural flotation as it is directed by the
¦ flowing blood, for example, in the vessel to the desired
¦ location.
¦ ~len the desired local:ion is reached, as sho-.~m in
¦ Figure 3, further fluid ~rom the fluid source is introduced
preferably under pressure as before through the catheter
I assembly to further expand balloon 38 until the balloon seals
¦ against the inner wall 54 of vessel 50~
¦ When a satisfactory seal has occurred, detachment is
¦ then ~nit;ated in the manner depicted in Figure 4. ~urther
¦ fluid from the.fluid source is introduced through the cannula
¦ and thepin and back pressure forces the fluid to exit through
¦ side opening 32 in the pin into small chamber 48. Expansion
¦ of the balloon portion surrounding small chamber 48 causes the
¦ mouth portion 40 of the balloon to expand and detach from
¦ frictionai ensagement with ex~anded end portion 28 o the
¦ cannula. This permits the cannula and frictionally hela
20 - ¦ pin to withdraw from the balloon 38. Materials are chosen so
¦ that the frictional engagement between the cannula and the pin
¦ is greater than the frictional engagement between the self-
¦ sealing plug 34 and thepin. Thus the pin will withdraw from
¦ plug 34 and will detach with the cannula from the balloon 38~
2~ ¦ Naturally the balloon engagement wi$h the interior wall 54 of
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the vessel will retain the balloon in p~sition while the,
can~ula 22 and pin 26 are withdrawn therefrom The arrow in
Figure 4 shows the direction of withdrawal of the cannula and
connectea pin.
As pin 26 is withdrawn from self-sealing member 34, the
self-sealing member 34 in cooperation with the surrounding
elastomeric string 46 will close and seal the open end of
balloon 3~ in expanded condition with the fluid 51 therein,
as shown in Figure 5. The nature of the balloon filler fluid
is such that with a semi-Dermeable ~emb~ane formed of a material
such as S~TIC r~r for the balloon, extra cellular fluid bathing
¦ the balloon, does not accummulate within the balloon because
¦ there is no significant osmotic gradient. The chosen fluid
¦ proviaes adequate opacification and prolonsed occlusion is
1~ ¦ possible, par~icularly if the balloons are not over-inflated at
. I the time of embolization. The result is an effective vessel
¦ occlusion with the use of a detachable balloon, as shown in
Figure 6.
Successful examples of the above procedure were carried
out wIth a number of catheter assemblies of the above discussed
type. Under local anesthesia via left carotid artery cut-down
and catherization, balloons were detached into the hepatic,
gastrosplenic, renal, internal iliac and ~rofunda femoral
arteries. Uninflated balloons-l mm in outside diameter (0.040
inches) were mounted on a 0.6 mm (0.023 inches) polyurethane
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¦ catheter and introduced through a five French polyethylene
¦ catheter. The balloon catheter ~as injected through the
introducing catheter after coiling the former in a fifty ml.
. syringe filled with fiushing solution Once the balloon cathete
.5 emerged from the introducing catheter ~slight distention of the
balloon with radiopaque contrast media allowed flow direction of
the balloon to the final site of embolization.
In a number of balloon catheters introduced in the above
manner, a radiopaque contrast media of 60 percent sodium-.
10 meglumine diatrozoate (R-60) in the amount of 0.15 to 0.2 ml.
was util;zed to render the balloons radiopaque. In a further
. selected number of balloons, R-60 was diluted to a 30 percent
ioaine concentration (R-30) with the addition of sterile water.
. Following balloon detachment in the above described manner,
post-occlusion angiography was performed via the introducing
catheter. The results were observed by serial radiographs
obtained over an extended period to demonstrate that, among
other factors, that the osmolarity of the distending contrast
. media is an important variable influencing the permanency of
SILASTIC rubber balloon occlusion. .
. Sodium-meglumate diatrozoate, in the concentrations .
utilized, has osmolaritieS of 1511 and 680 mOsm/l, ~hich
are significantly higher than blood (270-290 mOsm/l).
. Silastic r~bber appeared to bbhave like any s~-p~able nembrane.
Extra cellular bathing the balloon crossed the Silastic r~r
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membrane thereby reducing the osmotic gradient. These effects
were much less apparent with R-30 than with R-60 solutions.
The tests also show that care should be taken not to over-
inflate the balloons at the time of embolization. The results
show that prolonged occlusion is possible with the technique
as described above.
It is suggested that contrast agents be employed
with osmolarities near that of blood. With this in mind,
another effective contrast agent is cholografin Meglumine
manufactured by Squibb, Inc., of Princeton, New Jersey 08540~
The undiluted 52 percent Ioditamide Meglumine solution has an
iodine concentration of 260 mg. of iodine/ml and an
osmolality of ~30 milliosmoles~liter. This means that this
material can be diluted by one-third and achieve the same
radiopac;ty as Metri~amide at an osmolality which is just
slightly over that of blood. A series of ~n ~itro measurements
of changes in osmolality were made after using dilute
Cholog~afin with balloons of the above type, showing essentially
no change in osmolality five days after the balloons were
placed in saline.
In summary, silicone behaves like a semi-permeable
membrane and permanency of detachable balloon inflation is
dependent on the osmolar~ty of the filling substance within
the volume limits of detachable balloons. Detachable balloons
f;lled with hyperosmotis contrast agents swell and lose
radiopacity. In testing with two contrast agents, one
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of1500 millisomoles/liter and the other with 691 milliosmoles/
'~ - liter resulted in confirmation in vivo that balloon swelling
occurred and there was decreased radiopacification on serial
radiographs. It was also detlermined that balloons filled
with ~he ~ypoersmotic contrast agents would ru~ture before
those filled with less osmotically active radio opaque filler.
Further confirmation of the importance of osmolarity
was determined by using ~etrizamide, an iso-osmotic contrast
agent. None of the experiments employing the Metrizamide
balloons ruptured after five months of observation. Testing
also confirmed in vitro that silicone is a semi-permeable
membrane. This was accomplished by placing balloons filled
with contrast agents of different os~olarity in saline and
measurIng percent changes of 12 hours, 36 hours and 5 days.
This confirme~ conclusively in vitro that the osmolarities
fell in the balloons filled with hyperosmotic contrast agents.
Thus, there was transfer of fluid across the semi-permeable
mem~rane which would account for early rupture of balloons.
It was also observed that balloons filled with hyperosmotic
contrast agents would increase in size.
Thus the several aforenoted ~bjects and advantages are
most effectively attained. Although several somewhat preferred
embodiments have been disclosed and described in detail herein,
it should be understood that this invention is in no sense
limited thereby and its scope is to be determined by that of the
appendea claims.
