CA1160128A - Therapeutic method of use for miniature detachable balloon catheter - Google Patents

Abstract

THERAPEUTIC METHOD OF USE FOR MINIATURE
DETACHABLE BALLOON CATHETER

ABSTRACT OF THE DISCLOSURE
A therapeutic medical procedure utilizing a miniature balloon catheter of the type including a resilient cannula adapted for attachment to a source of fluid in having a small outer diameter for insertion into small vessels containing fluid and an inflatable balloon having a mouth at the proximal end thereof. The balloon is attachably mounted on the end of the cannula in fluid communication therewith and the balloon is designed to seal when the cannula is attached therefrom.
The medical technique includes inserting the balloon catheter into a small vessel and permitting the catheter to advance to a desired location in the vessel. The balloon catheter is attached to a source of fluid having an osmolarity substantially the same as the fluid in the vessel and the balloon is inflated to the volume limits of the balloon with fluid from the fluid source through the cannula until the balloon is fixed in position in the vessel. The cannula is then detached from the balloon and removed from the vessel. The mouth of the inflated balloon is self-sealed with the fluid from the fluid source therein to maintain the balloon in inflated position for an extended period of time thereby creating a vessel occlusion.

Description

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Il ,, ~I THERAPEUTIC METHOD OF USE FOR MINIATURE DETACHABLE
BALLOON CATHETER
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; BACKGROUND OF THE INVENTION
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I The development of m~ure balloon catheters for use ¦in small tortuous locations such as neurological blood vessels lis an extremely active and dynamic field. The development can ,~be traced through the work of Dr. Serbinenko of Russia ¦ as published in the Journal of Neurosurgery, Volume 41, August 1974, pages 125-1~5 and entitled Balloon Catherization and Occlusion of Major Cerebral Vessels. An exa~ple of more recent work in the area is present in U. S. Patent No. 4,085,757 issued to Dr. Paul H. Pevsner on April 25, 1978.
I¦ The rapid development of the art is readily apparent ¦! and the visible field of use becomes greater as experimental iiwork continues within the medical profession. A variety of jimproved designs for miniature balloon catheters for detachment, perfusion and other purposes are being developed at rapid rate jwith improvements being conceived constantly. Naturally llproceeding hand-in-hand with the improved devices is a sequence lof improved techniques in ~he use of balloon catheters both for Ineurological purposes and for use in other boay vessels and icavities.

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¦ Original developments in the use of detachable perfusio~, I balloons were primarily directed toward the diagnosis and treat- !
¦¦ ment of neurological diseases; In certain instances larger ¦ non-detachable balloons have been utilized for emergency pre-i ope~ative control of hemmorrhage in the abdominal circulation, but most efforts have centered about therapeutic embolization ¦ with a variety of materials.
One particular area open for development is in the use of the detachable balloon occlusion as offering a method for jprecise and possibly long-term occlusion without the dangers of inadvertent embolization associated with the injection of particulate matter through a catheter. There is very little data available describing the possible variables influencing balloon occlusion.
ISU~MARY OF THE INVENTION
I With the above background in mind, it is among the ~primary objectives of the present invention to present a technique for use of detachable balloons fox thexapeutic emboliza-tion. The objective is accomplished by the consideration of the osmolarity of radiopaque media used to fill the balloon~ A
description of the development of the present invention appears in Radiology, Volume 126, No. 2, pages 521-523, published in February 1978 and entitled Therapeutic Embolization With ~Detachable Balloons.
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I As pointed out in the ab~ve publication dealing with the jsubject matter of the present invention, osmolarity pf the d~s~
tending con_rast media is an important variable influencing

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the permanency of ~alloon occlusion, particularly where the balloon is of a semi-permeable material sych as a silicone membrane commonly known as SILASTIC rubber. It is an objective to ~lse a fluid to produce the desired conditions ~or long term embolizations.
In utilizing a semi-permeable membrane material such as a silicone material for the expandable balloon, for example a SIL~ IC rubber balloon, the following compounds have been found effecti~e to produce the desired osmolarity condltions ~particular-ly for radiopaque contrast media. A first is R-60 manufactured by Squibb, Inc., Princeton, New Jersey 08540 containing 60~ Na-meglamine diatriæoate diluted to a 30 percent iodine con-centration and identified as R-30. A second is METRIZAMIDE, a non-ionic, fluid contrast medium manufactured by Sterling-Winthrop Research Institute of Rensselaer, New ~ork 12144. A
third is Iodipamide Meglumine manufactured by Squibb, Inc., Princeton, New Jersey 08540 currently available for intro-vascular use and nearly iso-osmotic ~hen diluted by 30% with 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 detachable ba~loon.
In order to prevent premature or undue swelling and rupturing as well as loss of radiopacacity of the balloon implant , a ra~iopaqu~ filler of similar osmolarity to blood is used. As * Trade Marks 116UlZ~3 ~

a result, the longevity of the balloon is increased and a more effective and better therapeutic embolization is achieved.
In summary, a therapeutic medical procedure is provided utilizing a miniature balloon catheter of the type including a resilient cannula adapted for attachmen~ to a source of fluid and having a small outer diameter 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 the catheter to close the mouth of the balloon when the cannula is detached therefrom. The procedure involves inserting the balloon cathetex into a small vessel. The catheter is advanced in the vessel to the desired location. The balloon catheter is attached to a source of fluid having an osmolarity substantially the 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 vessel. The cannula is then detached from the ~alloon and removed from the vessel. The sealing means seals the mouth of the inflated balloon with the fluid therein to ma~n tain the balloon in inflated position for an éxtended period oE
time to create a vessel occlusion.
In another embo~iment, the invention pr~ des ~ balloon-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 adapted for connection to a source of external fluid, said cannula having an outer diameter adapted for insertion into said fluid-containin~
vessel;

~60~Z8 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 vessel 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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I BRIEF DESCRIPTION OF THE DRAWINGS
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: ¦ In The Dr_wings~
¦ Figure 1 is a fragmentary sectional view of the I catheter utilized in performing the medical procedure of the . ¦ inv~ntion;
¦ ~ ~igure 2 is a fragmentary sectional view of the ¦ catheter inserted into a small vessel and partially expanded by introduction of fluid so that the catheter is floated . along with the liquia in the vessel to the desired location;
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 therefrom and the balloon sealed;
Figure 6 is a fragmentary sectional view thereof with the cannula having been removed from the balloon and the balloon being retained in sealed expanded position in the vessel with flui~ therein to create a vessel occlusion.
DETAILE:D DESCRIPTION OF THE PREFERRED EMBODIMENTS
The miniature balloon catheter assembly 2D adaptable 2~ for use in the medical technique of the present invention is shown in the drawings.

~ Z8 It inclu~les 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 p~rtion 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 ~4 mounted in the open end portion 36 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 as 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 located on the exterior surface thereof i5 an elastic band 46 of plastic or rubber material which assists in . ' ~l~iOlZB

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 removed 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 facilitate withdrawal of the cannula and pin therefrom during detachment.
The self-sealing plug 34 can be formed of any commonly used 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-troducing catheter until it is positioned within the vessel 50 as shown in Figure 2. The vessel 50 is filled with a fluid such as blood 52 traveling in the direction shown by the arrow in Figure 2. Radiopa~ue 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 accordingly through the passageway 30 ~OlZ~ ~

¦ in the pin 26 and into the hollow chamber 44 of balloon 38.
¦ Sufficient fluid 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 5 - ¦ location.
¦ When the desired location is reached, as shown in ¦ Figure 3, further fluid from the fluid source is introduced ¦ preferably under pressure as before through the catheter ¦ assembly to further expand balloon 38 until the balloon seals ¦ against the inner wall 54 of Yessel 50.
¦ When a satisfactory seal has occurred, detachment is ¦ then initiated in the manner depicted in Figure 4. Further ¦ fluid from the.fluid source is introduced through the cannula ¦ and thepin and bacX 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 ~rictional engagement with expanded end portion 28 OL the cannula. This permits the cannula and frictionally held 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 with the interior wall 54 of .

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the vessel will retain the balloon in position while the, cannula 22 and pin 26 are withdrawn therefrom. The arrow in Figure 4 shows the direction of withdrawal of the cannula and connected pin.
~s pin 26 is withdrawn from self-sealing member 34, the self-sealing member 34 in cooperation with the surrou~ding elastomeric string 46 will close and seal the open end of balloon 38 in expanded condition with the fluid 51 therein, as shown in Figure 5. The nature of the balloon filler fluid ~0 is such that with a semi-permeable membr`ane formed of a material such as S~STIC r~r for the balloon, ex*ra cellular fluid ba~ng the balloon, does not accummulate within the balloon because there is no significant osmotic gradient. The chosen fluid provides adequate opacification and prolonged occlusion is possible, particularly if the balloons are not over-inflated at . 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 le~t carotid artery cut-down and catherization,- balloons were detached into the hepatic, gastrosplenic, renal, internal iliac and profunda femoral arteries. ~ninflated balloons--l mm in outside diameter ~0.040 inches) were mounted on a 0.6 mm (0.023 inches) polyurethane 1 ~16012B

catheter and introduced thr~ugh a five French polyethylene catheter. The balloon catheter was injected through the introducing catheter after coiling the former in a fifty ml.
syringe filled with fiushing solution. Once the balloon cathete3 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-meglumine diatrozoate (R-60) in the amount of 0.15 to 0.2 ml.
was utilized 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.
. ~ollow;ng 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 ~ariable influencing the permanency of SILASTIC rubber balloon occlusion.
Sod~um-meglumate diatrozoate, in the concentrations utilized, has osmolaritieS Of 1511 and 680 mOsm/l, which are significantly higher than blood (27~-2g0 mOsm/11.
Silastic r~bber app~d to behave like any semi-p~able ~rane.
Extra cellular bathing the balloon crossed the Silastic r~

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membrane thereby reducing the osmotic gradient. These effects were mu~h le-~s app~rent 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 i5 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 ~rinceton, 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 radiopacity as Metri~amide at an osmolality which is just slightly over that of blood. A series of ~n vitro measurements of changes in osmolality were made after using dilute Cholografin 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 osmolarity of the filling substance within the volume limits of detachable balloons. Detachable balloons f~lled with hyperosmotic contrast agents swell and lose radiopacity. In testing with two contrast agents, one * Trade Marks ~ 60128 of1500 millisomoles/liter and the other with 691 milliosmoles/
,~ liter resulted in confirmation in vivo that balloon s~elling occurred and there was decreased radiopacification on serial radiographs. It was also determined that balloons filled with the hypoersmotic contrast agents would rupture 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 rletrizamide 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 aa~s.
This confirmed 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 membrane which would, account for early rupture of balloons.
It was also observed that balloons filled with hyperosmotic , 20 contrast agents would increase in size.
'Thus the several aforenoted objects and advantages are most effecti~ely attained. Although several somewhat preferred embodiments hav'e been disclosed and, described in detail herein, it should be understood that this invention is in no sense ~5 limited thereby and its scope is to be determined by that of the appended claims.

Claims (4)

CLAIMS:

1. An inflated balloon device implanted in a fluid-containing vessel and producing an embolization thereof comprising:
a fluid-tight balloon member of semi-permeable material expanded against the walls of said fluid-containing vessel in fixed engagement therewith; and a fluid sealed inside said balloon member in sufficient quantity to effectuate the expansion of said balloon member, said expansion fluid having an osmolarity property substantially the same as the osmolarity of the fluid in the vessel and being a contrast agent.

2. The assembly of Claim 1, wherein said semi-permeable material is silicone rubber.

3. The assembly of Claim 1, wherein said expansion fluid has an osmolarity property substantially the same as the osmolarity of blood.

4. An inflated balloon device implanted in a blood vessel and producing an embolization thereof comprising:
a fluid-tight balloon member of semi-permeable material expanded against the walls of said blood vessel in fixed engagement therewith; and a fluid sealed inside said ballon member in sufficient quanti-ty to effectuate the expansion of said balloon member, said expansion fluid having an osmolarity property substantially the same as the osmolarity of blood and being a contrast agent.