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Patent Practice and Procedure
IPSE '98
Final Exam

INSTRUCTIONS: This is an open book examination. You may use the MPEP, your class materials, and other materials you think might be helpful. Your exam number and Section Teacher's name should be placed on your blue book. Section I consists of a claim drafting and written response exercise and Section II consists of 15 True/False questions and 5 short answer questions.

After completing IPSE, you are hired as a patent agent at a prestigious New York City law firm. Anxious to be a successful rainmaker from the start, you have joined all of the local inventor clubs and met your very first client Mrs. Patricia Onback. Mrs. Onback was quite upset that the U.S. Patent Office (USPTO) had rejected a patent application she had filed pro se. She asserts that her invention is a breakthrough in psychological development. Despite her initial determination to obtain the patent without the help of an attorney, she has retained your services to assist her in responding to the first Office action.

The application was assigned Serial No. 01/111,111 and is being examined by Examiner Pierce in Group Art Unit 372. On April 16, 1998, Examiner Pierce mailed a first Office action and set a three month shortened statutory period for response. The Examiner's Office Action includes the following rejections:

Claims Rejections - 35 USC S 112, 2d para.

1. Claims 1 and 2 are rejected under 35 USC § 112, 2nd paragraph as being indefinite for failing to particularly point out and distinctly claim what applicant regards to be the invention. Claim 1 is overly broad and does not recite exactly how the simulated hand applies a pat to the users back. Claim 2 merely recites an aggregation of elements with no interrelationships. Also, in claim 2, "said simulated hand" lacks antecedent basis.

Claims Rejections - 35 USC § 102

2. Claim 1 is rejected under 35 USC § 102 as being anticipated by the admitted prior art in the background of the invention. The well known back scratching or massaging apparatus admitted by the inventor to be prior art includes a

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"simulated" hand and inherently applies a pat to a users back. The psychological state of mind of the user is given no patentable weight.

Allowable Subject Matter

3. Claim 2 would be allowable if rewritten or amended to overcome the rejection under 35 U.S.C. 112 set forth in this Office action.

The following is a copy of the originally filed specification, claims and drawings:

PAT ON THE BACK APPARATUS

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to an apparatus which is useful for providing a self-administered pat-on-the-back or a congratulatory gesture. More particularly, this invention relates to an easily disassembled, portable and body mounted device which may be used for amusement or for a needed psychological lift.

(2) Description of the Prior Art

It is well known in the art and practice of self-administered positive reinforcement activity that various techniques can be successfully employed to extol the virtues of one's actions and thoughts. Historically, much of the material available to the individual has been in the form of written material which must be read or studied as part of a course of self-improvement. More recently such technical advances as recorded media has made available voice and visual recordings in which one may engage in the development of a positive mental attitude (PMA).

Most frequently, one who is in need of congratulations or encouragement often tells friends or work associates of his or her feelings and solicits a needed-pat-on-the-back. In the absence of other persons or of persons either friendly or sensitive to one's needs the individual must resort to raising their arm and hand high into the air overhead and bending the arm at the elbow to allow the hand to gently strike the upper portion of the back. This places one in a somewhat uncomfortable posture and additionally lacks the placement of a pat in the most desired middle portion of the back. Accordingly, the subject invention is directed toward an apparatus useful for providing a self-administered pat-on-the-back.

Various prior mechanical devices are known which use an arrangement of mechanical elements to apply force of contact with a person's back without the aid of another person. Such arrangements generally comprise a complicated assembly of levers, rods, axles and components to apply medicaments or special massage to the back of the user.

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Another type of back contact device consists mainly of implements with which the user may reach certain parts of the back such as for relieving an annoyance, for example, an itch. Such back scratching devices are usually of a rod type shape sometimes with fingers extending from the end for applying a back and forth motion to the skin of the user's back. Still other known designs of self-administered physical contact include such devices that impart a negative behavioral attitude and tend to reduce self esteem. One such device uses a boot to kick the user in the buttocks.

In this regard, the subject invention is directed toward a back patting device providing for specific uses in the area of amusement and self-congratulation and makes available to the user self-administered pats such as are not available with the devices in the heretofore known prior art.

BRIEF SUMMARY OF THE PREFERRED EMBODIMENT OF THE INVENTION

A pat-on-the back apparatus that applies a congratulatory pat with a simulated hand to a users back when the user needs a psychological lift.

THE DRAWINGS

The objects and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawings where:

FIG. 1 is a pictorial view of a manually operated self-congratulatory apparatus of the type to advantageously utilize the subject invention; and

FIG. 2 is an exploded view showing the essential and optional component parts and their relationship to each other in the subject inventive pat-on-the-back device.

DETAILED DESCRIPTION

The self-congratulatory apparatus indicated in FIG. 1 generally at 10 is supported primarily during use by resting the extending support member 12 on the shoulder. Shoulder block 16 acts to receive the extending support 12 and to distribute the weight of the mechanism evenly over a broad area. A guide rod 18 shown being grasped by the right hand of the user allows a desired tilting of the device to establish the proper angular positioning of the extending support member so as to allow the arm 20 and attached simulated hand 24 to fall freely by force of gravity to a retracted position away from the users back. A-long the length of the arm, an attachment 26 fixes a flexible connector 28 such as a fancy rope or ribbon to the arm for grasping in the free hand of the user. By exerting a pull or tug on the flexible connector or rope 28 the user urges the hand into contact with the back to effect a much needed pat-on-the-back for amusement or for a psychological lift for a job well done, a goal completed or to magnify a feeling of well being.

To operate the device of the present invention, the user simply places the apparatus on either shoulder, holds the guide rod or handle 18 in one hand and tilts the handle so that the support member 12 assumes the proper angular relationship with the back. The user then grasps the rope or ribbon connection 28 with the free hand and gives the rope a gentle pull until the back receives a gentle pat with simulated hand 24 or a more firm pat should that be desirable. Then by either releasing the rope or by moving the hand

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holding the rope so the rope slackens, the hand and arm retract by force of gravity to assume a ready position for a succeeding stroke.

Turning now to the remaining drawing, FIG. 2, there will be seen an illustrative embodiment of the subject inventive self-congratulatory apparatus wherein an exploded view of the arrangement of the component parts is presented.

It should be noted that the extending support member 12 which is shown as a rod may be made from a wooden dowel rod about 1/2 inch in diameter and about 12 inches long. An arm 20 is pivotally joined to the extending support member at a pivot 22 located at the ends of the support member and the arm. Here two pivot support blocks 32 and 34 residing at the ends of the support member 12 and the arm 20 respectively are provided with mutually aligned bore holes 54 for receiving a long screw connector 36 having an expanded head 40 and receives a cap nut retainer 38. Located at the opposite end of the arm which is also conveniently made of 1/2 inch dowel rod about 16 inches long is a flat planar simulated hand 24 which may be cut with a jig saw from a blank of 2/4 inch stock and provided with digits 56 of a shape so as to call to mind the fingers on a human hand. The hand 24 may be conveniently provided with a blind bore 42 in the palm termination edge for fittingly receiving the rod 20 forming the arm. A flexible connector 28 such as fancy rope, cord string or ribbon is attached to the arm 20 by tying a simple knot around the cylindrical shaft 20 or by an attachment 26 which may comprise a through bored hole in the rod to locate the connector at a fixed point on the rod or by a screw-in eyelet for tying or otherwise fixing the connector to the arm.

A shoulder block 16 having a contoured lower surface 30 for comfortable placement onto a human shoulder is provided with a blind bore 44 on the upper surface 56 opposite the contour 30 and the bore is angled at about 135 degrees with the upper surface 58 to give the necessary rise and run relationship to the upwardly extending support member 12. A second blind bore (not shown on the drawing) is provided in the front face of the shoulder block for receiving a guide rod 18 useful in steadying the apparatus when in use. Here the bore is angled with regard to the upper surface 58 so as to allow the guide rod to extend in a downward manner making it easy to grasp with the user's hand. The shoulder block is made of stock material about 1 1/2 inches thick and all edges are preferably rounded.

With the exception of the metal screw connection 36 and associated capnut retainer 38 all parts of the rigid structure may be made of soft wood materials. The rods and bores are preferably sized such that a slight interference fit is produced so as to make assembly and disassembly practical yet produce a rigid structure that remains structurally integral during use. of course, the connector shown as screw 36 may be simply a wooden peg with split and expanded ends or another attachment configuration of the type known to those skilled in the art. It is of course also practical to consider other materials for manufacture for the entire apparatus such as modern polymer plastics. Also within the metes and bounds of the present invention is a permanent attachment of the structural elements. In another variation the support member 12 and the arm 20 may be directly connected without the aid of pivot block 32 for the support member and the pivot block 34 for the arm. In this arrangement the ends of the dowel rods are simply bored or drilled with matching, aligned holes for attachment by means of a connector such as a screw 36 used with a retainer such as a capnut 38.

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The pivot blocks 32 and 34 are conveniently made from wooden blocks which are 1 inch by 1 inch by two inches. In an optional arrangement shown in FIG. 2, a circular torsion spring 46 resides between the two blocks 32 and 34 and has a retaining hook 60 formed on each of the free ends of the spring. The retaining hook 60 is received into corresponding torsion spring retaining holes 48 (only one shown) residing in the facing surfaces of the pivot blocks 32 and 34. This spring resiliently biases the pivot blocks and the support member and arm to cause them to tend to separate toward a right angle.

In still another optional arrangement, a modified flexible connection 28 attaches to both the swing arm 20 and to the extended support member 12. Here a small circular loop 50 resides on a second rope or cord 52 being of short length. The loop 50 encircles the rod member 12 and the secondary connector cord 52 is joined to the primary rope connector 28. Such an arrangement provides a tensioner for the torsion spring arrangement and the length of the secondary cord is selected such that the arm is restrained from straightening out yet sufficient slack is available to satisfactorily operate the arm to cause contact of the hand with the back of the user.

In each of the foregoing embodiments it can be seen that a simple yet entertaining and amusing arrangement of readily available components has been assembled into an inventive combination of useful proportion. Further, such an apparatus is easy to operate to provide a needed pat-on-the-back for a job well done or a psychological lift to allow a person to overcome some of the "valleys" of emotional life in a highly technicalized society that often postpones the level of immediate personal approval desirable for continued accomplishment.

The inventive unit is easily disassembled and reassembled both for transport and for concealment from early discovery until ready for use. This adds to the amusement value. The light weight and attractive assemblage of rods and contoured, soft edged elements contribute to ease of use.

In describing the invention, reference has been made to a preferred embodiment and illustrative advantages of the invention. Those skilled in the art, however, and familiar with the instant disclosure of the subject invention, may recognize additions, deletion, modifications, substitutions and/or other changes which will fall within the purview of the subject invention and claims.

What is claimed is:

1. A pat-on-the back apparatus that applies a congratulatory pat with a simulated hand to a user's back when said user needs a psychological lift.

2. The pat-on-the back apparatus comprising said simulated hand, an a support member, a flexible connector, a shoulder rest, and a rod.

5

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SECTION 1 (30 Points)

Prepare a timely and complete response to the above Office Action including an amendment that will overcome the examiner's rejections under 35 U.S.C. 112, 2nd paragraph and 35 U.S.C, 102 and that will clearly place the application into condition for allowance. After the amendment, 2 claims should be pending in the application - 1 independent claim (15 points) and 1 dependent claim (5 points). A timely and complete response should comply with 37 CFR 1.111 (5 points) and the amendments should comply with 37 CFR 1.121 (5 points).

In the claims, you must use terminology having support in the original disclosure as filed. No credit will be given for a Jepson type claim. Points will be deducted for: claiming subject matter not within the scope of the original disclosure, means plus function claim language; using claim language which is vague and indefinite; using claim language which does not have antecedent basis; failing to positively recite elements and interrelate elements in the article claim; claiming unnecessary limitations in the independent claim; presenting a claim that defines an inoperative invention or is anticipated by the prior art; misspelled words and poor grammar; and failing to follow these directions.

SECTION 11 (30 Points)

TRUE/FALSE (1 point each)

1. In the above Office action, the proper grounds for rejecting claim 1 as being overly broad should be under 35 USC Section 112, First Paragraph, NOT under 35 USC Section 112, Second Paragraph.

2. In the above Office action, the rejection of claim 1 under 35 USC Section 102 over admitted prior art described in the Background of the Invention is improper because the examiner is improperly using hindsight reasoning by using the applicant's own disclosure.

3. The reason for the definiteness requirement of 35 USC Section 112, Second Paragraph, is to enable one of ordinary skill in the art to make the best mode of the invention.

4. The transition phrase "consisting of" is an open-ended transition that should be used in mechanical claims to broaden the claim.

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5. For claim 1 to be anticipated under the principles of inherency, the prior art back scratching apparatus must necessarily provide a "'pat" on the back during its normal and intended operation.

6. If a complete response is not filed in the above case by October 16, 1998, the application will be abandoned unless the response is filed using the Express Mail procedure of 37 CFR 1.10.

7. Means plus function language is interpreted by the examiner to cover all means capable of performing the stated function.

8. If Mrs. Onback improved on this apparatus by adding a motor that causes the hand to pat the back, this feature could be added to the pending application if a new declaration were filed together with the amendment,

9. Intentional designing around patent claims is one of the ways in which the patent system works to the advantage of the public in promoting progress in the useful arts, its constitutional purpose.

10. If the claim includes unnecessary limitations, the examiner will likely reject the claim as being too narrow in scope.

11. If an information disclosure statement in accordance with 37 CFR 1.98 is filed after a patent application is filed but before the mailing date of a first Office action on the merits, the information disclosure statement will be considered by the patent office without having to pay an additional fee.

12. An affidavit under 37 CFR 1.132 presenting evidence of commercial success is an effective way to overcome an anticipation rejection under 35 U.S.C. 102 provided there is a nexus between the commercial success and the claimed invention.

13. If a continuation-in-part application claims the benefit of an earlier filing date in the U.S. under 35 U.S.C. 120, the 20 year patent term is measured from the earlier filing even for the new subject matter added to the continuation-in-part application.

14. If an amendment is made in the above application to Mrs. Onback and the examiner rejects the amended claims over a newly discovered prior art patent, the examiner is entitled to make the second rejection final if it was necessitated by the amendment.

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15. If an amendment to the claims results in a new matter rejection under 35 U.S.C. 112, 1st paragraph, the applicant cannot rely on the drawings as support for the new matter because the drawings are not a "'written description" under 35 U.S.C. 112, 1st paragraph.

SHORT ANSWER (3 points each)

16. Which required section of the above patent application is missing and what is its purpose?

17. What must the examiner show to require a restriction? What must the applicant do to respond to a restriction requirement?

18. What must the examiner show to make out a prima facie case of obviousness?

19. 35 U.S.C. 103 states that "'A patent may not be obtained... if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious..." Name three ways in which an applicant might argue that the subject matter as a whole would not have been obvious.

20. A patent application was filed in the U.S. on May 22, 1998 identifying John Smith as the sole inventor. Under what sections of 35 U.S.C. 102 do the following references qualify as prior art?

a) A U.S. patent issued on June 1, 1998 to inventors William Jones and John Smith (the same individual in the patent application) having a filing date of May 21, 1997.

b) A European patent application published by the European Patent Office on April 1, 1997 identifying John Smith (the same individual in the patent application) as the sole inventor.

c) An international application under the Patent Cooperation Treaty (PCT) published on June 1, 1997 and identifying William Jones and John Smith (the same individual in the patent application) as joint inventors.

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Patent Practice and Procedure

IPSE '98 Final Claim Drafting Assignment

INSTRUCTIONS:

Please identify your Section Teacher and include EXAM NUMBERS ONLY on the assignment. The assignment is to be turned in to the registrars Office by 4 p.m. on Thursday July 9. You are allowed to use the MPEP, any course materials, and other resources on patent claim drafting. You are NOT allowed to do any patent searching! Doing so will be a violation of the honor code.

You have recently been hired as in-house patent counsel for International Medical Products (IMP), Inc., a company that Stents are devices implanted within pioneered coronary stents. an artery of a patient to open a blockage within the artery. To encourage innovation, the company offers a monetary bonus of $500 to employees with new inventions related to stents and stent delivery systems. The inventors are asked to record their inventions and other relevant information on an Invention Record Form. After the Invention Record is prepared, a patent search firm conducts a preliminary patentability search. If the results of the search appear favorable, the Invention Record is given to one of the in-house patent attorneys to prepare a patent application.

The senior patent counsel has given you an Invention Record prepared by two of the engineers at the company. The senior counsel has instructed you to prepare claims that will distinguish over any prior art discussed by the inventors or discovered in the preliminary search and provide the broadest possible scope of protection. The senior counsel has specifically asked for a total of 10-15 claims (at least 2 independent claims) including both apparatus claims and method claims. However, no additional filing fees are to be incurred beyond the base fee. The senior counsel encourages you to be your own lexicographer if necessary to define the invention but is opposed to means plus function language. Where new terms or phrases are used, the senior counsel has asked that you briefly define those terms in reference to the elements described and shown in the Invention Record. The senior counsel has also stated that all new attorneys are expected to draft claims that have proper structure and format and that are free from antecedent basis problems and other indefinite language.

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Patent Practice and Procedure

IPSE '98

INVENTION RECORD

TITLE OF INVENTION Stent Delivery System

INVENTOR (S) :

Maxwell J. Baker
William C. Markush

DESCRIPTION OF INVENTION:

DESCRIPTION AND PURPOSE OF INVENTION
(INCLUDE DRAWINGS IF NECESSARY)

Refer to the attached Figures 1-7.

Fig. 1 shows the new stent delivery system. The catheter 10 has a tubular body 12 with a distal end 14 and proximal end 16. The catheter carries a pair of longitudinally displaced polyethylene balloons 18, 20. The balloon 18 closest to the distal end 14 is used to dilate a narrowed section 19 in an artery 17 (Fig. 2). The narrowed section 19 is typically caused by a blockage commonly referred to as a stenosis. The other balloon 20 is used to expand and implant the wire mesh stent 21 against the narrowed section 19 of the artery.

The tubular body consists of an outer tube 22 and an inner tube 24 having a lumen 26 (Fig. 2) connected at the proximal end 16 to a coupling 28. The lumen 26 conveys a pressurized gaseous medium from the coupling 28 to the balloon 18 for expanding the balloon. Another lumen 30 formed between the inner tube 24 and the cuter tube 22 is coupled to a coupling 32 at the proximal end and conveys a gaseous medium to the balloon 20 to expand the balloon 20. To introduce the catheter 10 into a patient, a conventional guide wire 40 extends through a lumen 42, which extends from an end hole 44 to a wall hole 46 in the catheter 10. Figure 2 shows the tubes 22, 24 and lumens 26, 30, 42 in cross-section.

As shown in detail in Figure 3, wider sections 111, 112 are provided on both sides of the stent balloon 20. The compressed wire mesh stent 21 is arranged around the balloon 20 in between the wider sections 111, 112, such that the stent 21 is prevented from sliding off of the balloon 20. Rings 114, 115 received inside the balloon 20 form the wider sections, 111 and 112. The ring 114 is arranged around the inner tube 24 and the ring

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Patent Practice and Procedure
IPSE 198

115 is arranged around an end 118 of the outer tube 22. By arranging the rings 114, 115 inside the balloon, they do not interfere with the unfolding of the balloon 20 and the balloon forms a smooth "skin" over the rings 114, 115. The rings 114, 115 can be made of a material that is visible when subjected to X-rays so that the position of the rings 114, 115 can be used to position the stent 21.

The method of using the stent delivery system is illustrated in Figures 4-7. The distal end 14 of the catheter 10 is introduced into an artery 17 until the first balloon 18 is positioned at the stenosis 19 to be dilated. The gaseous medium under pressure is supplied via the coupling 28 through the lumen 26 of the inner tube 24. Via the opening 29 in the wall of the inner tube 24, the pressurized gas flows into the balloon 18 and expands the balloon 18 to dilate the stenosis section 19 of the artery (Fig. 4).

Next, the pressure inside the balloon 18 is reduced and the balloon 18 resumes its original shape. The catheter 10 is advanced further into the vessel so that the balloon 20 will be situated at the now dilated section 19 of the blood vessel. Pressurized gas is supplied to the balloon 20 via coupling 32 and the annular interspace 30 connected to the inside of the balloon -'0 (Fig. -5). The pressurized gas expands the balloon 20

and the stent 21, implanting the stent against the dilated section 19. The balloon 20 is then deflated to its original shape, and the catheter 10 is withdrawn (Fig. 6). The stent 21 remains behind in the stenosis section 19 (Fig. 7)

FORMER APPROACHES AND DISADVANTAGES The former approach was to use two different catheters. First, a catheter having a relatively small dilation balloon was inserted to the stenosis in the artery to expand or dilate the stenosis. Then, after the stenosis has been dilated, the small dilation balloon is withdrawn and another catheter having a larger balloon carrying the stent is inserted to the stenosis. The disadvantage is that two catheters are needed. Also, the dilated stenosis may recollapse before the second catheter with the stent can be inserted. The only other multiple balloon catheters available are used only for dilating the stenosis and are not used for stent deployment.

Also, in the existing catheters used to deploy stents, the stent will often slide off of the balloon. In some systems, a guiding catheter or sheath must be positioned over the stent as the catheter is moved through the artery to the lesion to prevent the stent from sliding off. When the stent is properly positioned, the sheath is retracted and the balloon is expanded to deploy the stent.

FEATURES BELIEVED TO BE NOVEL >

A double balloon stent delivery system used to both dilate the stenosis in an artery and deploy a wire mesh stent to the stenosis.

ADVANTAGES OF INVENTION OVER FORMER APPROACHES

Only one catheter is needed to dilate the blockage in the artery and to expand and deploy the stent to keep the blockage open. This single catheter procedure would require less time and prevent the dilated stenosis from re-collapsing before the stent is implanted. This procedure would also be less invasive, reducing the risk of infection in the patient. Further, the guide catheter or sheath used with other stent catheters is not necessary.

ALTERNATIVES OR IMPROVEMENTS PRESENT OR PLANNED

Any type of conventional stent can be used in addition to a wire mesh stent, and any number of balloons can be used. Alternative arrangements for the tubes and lumens can be used to provide the pressurized gaseous medium separately to each of the balloons. Another planned improvement is to have the dilation balloon made of a more pliable material to provide a more uniform load on the wall of the artery or vessel. Having the stent balloon made of a less pliable material provides a uniform expansion of the stent. Alternatively, the balloons can also be made of the same material with the dilation balloon being made more pliable by reducing the balloon's wall thickness.

COMMERCIAL APPLICATIONS

In hospital surgical units.

INVENTORS SIGNATURE(S):
	DATE:
	DATE:

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Patent Practice and Procedure
IPSE '98

Patent Searching, Inc.
1 Jefferson Davis Hwy.
Arlington, VA

Senior Patent Counsel IMP, Inc. White St. Concord, NH 03301

Re: Preliminary Patentability Search
Your reference: Stent-98001

Dear sir:

We have completed our preliminary patentability search for the stent delivery system disclosed to us in your Invention Record. Our search included class 604, subclass 96. Examiner Jones in art unit 322 was also consulted. The only relevant patent discovered in our search is U.S. Patent No. 5,261,878 issued to Galindo on a DOUBLE BALLOON PEDIATRIC DUCTUS ARTERIOSUS STENT CATHETER AND METHOD OF USING THE SAME.

Very Truly Yours,

Pat N. Searcher

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United States Patent [19]
Galindo

US005261878A
[11] Patent Number:
5,261,878
[45] Date of Patent: Nov. 16, 1993

[54]	DOUBLE BALLOON PEDIATRIC DUCTUS ARTERIOSUS STENT CATHETER AND METHOD OF USING THE SAME
[75]	Inventor: Alvaro Galindo, Tarzana, Calif.
[73]	Assignee: The Regents of the University of California, Oakland, Calif.
[21]	Appl. No.: 885,946
[22]	Filed: May 19, 1992

[51]Int. Cl.5 A61M 29/00
[52]U.S. CT . 604/96, 606/194
[58] Field of Search ..............604/96-101,
6D4/53, 54, 55; 606/194
[56]
References Cited U.S. PATENT DOCUMENTS

4,456,011 6/1984 Warnecke 604/101
4,741,328 5/1988 Gabbay 604/99
4.771,765 9/1988 Choy et al . 604/101 X
4,794,928 1/1989 Kletschke 604/101 X
4,976,692 12/1990 Atad 604/101

OTHER PUBLICATIONS
Transluminally-Placed Endarterial Crafts-Dotter-Investigative Radiology Sep.-Oct. 1967 vol. 4, pp. 329-332.
Intravascular Stents and Transluminal Angioplasty-Sigwan et al.-New England Journal of Medicine, Mar. 19, 1987, pp. 701-706.
Expandable Intraluminal Graft: A Preliminary Study-Palmaz et al.-Radiology Jul. 1985, pp. 73-77. Atherosclerotic Rabbit Aortas: Expandable Intraluminal Grafting-Palmaz et al.-Radiology 1986; 160:723-726.
Expandable Intraluminal Vascular Graft: A Feasibility Study-Palmaz et al.-Surgery Feb. 1986, pp. 199-205. Expandable Intrahepatic Portacaval Shunt Stents:

Early Experience in the Dog-Palmaz et al-AJR 145:921-825, Oct. 1985.
Balloon-Expandable Intravascular Stent-Palmaz et al.-AJR 150.1263-1269, Jun. 1988.
Use of Endovascular Stents in Congenital Heart Disease-O'L.aughlin et al.-Circulation 1991;83:1923-1939. A Novel Method to Maintain Ductus Arteriosus Patency-Coe et al.-J Am Coll Cardiol 1991;18:837-841.
Use of Intravascular Endoprothesis . . . -Moore et al.-JACC vol. 17. No. 2, Feb. 1091:19A.
Redilating Ductal Stents in Newborn Lambs-Coe et al.-Abstracts From the 64 Scientific Sessions, 11-545. Introduction to Intravascular Stents-Richard A. Schatz-Cardiology Clinics--vol. 6, No. 3, Aug. 1988.
Primary Examiner-John D. Yasko Attorney. Agent, or Firm-Daniel L. Dawes

[57] ABSTRACT

A cardiac catheter for use in maintaining the patency of the ductus arteriosus in infants is provided with two inflatable balloons, a distal end balloon and a stent balloon. Each balloon is independently inflatable. The stent is carried temporarily on the stent balloon and is delivered by the catheter to the site of the ductus arteriosus. Expansion of the stent balloon expands the stent and places it at the target site. The stent balloon is confidently and reliably placed in the ductus arteriosus by first inflating the distal end balloon and withdrawing the catheter until abuts the opening of the ductus arteriosus through which it has been previously disposed. When this abutment is realized, the stent balloon is necessarily positioned appropriately within the ductus arteriosus. While maintaining the inflation of the distal end balloon, the stent balloon is inflated and the stent placed. After placement, both the distal end balloon and stent balloon are deflated and the catheter withdrawn.

20 Claims, 2 Drawing Sheets

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5,261,878

1

DOUBLE BALLOON PEDIATRIC DUCTUS
ARTERIOSUS STENT CATHETER AND METHOD
OF USING THE SAME

BACKGROUND OF THE INVENTION

I. Field of the Invention

The invention relates to the field of cardiac catheters and in particular to catheters used to place stents in infants and the methods by which such catheters may be used for pediatric stent placement.
2. Description of the Prior Art

Work began as early as 1969 using nonexpandable stainless steel coils in combination with angioplasty catheter techniques for the placement of stents in dog Is femoral arteries C. T. Dotter, "Transluminally placed coil spring endarterial tube grafts: Long term patency in canine popliteal artery Invest. Radial 4:329-331 (1969). Following Dotter, several different types of stent designs were devised, but each of these designs suffer from limitations which prevented their success in clinical application. These limitations included bulky configurations that made delivery to target lesions difficult, unpredictable expansion of the device, migration due to stent-vessel mismatch, abrupt thrombosis, or gradual restenosis from intimal hyperplasia.

Evolving from these early efforts are three basic designs which include a spring-loaded stent, usually made of stainless steel and constrained to a small diameter on a delivery catheter. The stent is allowed to spring open to a predetermined diameter when the constraint is removed. See Sigwart et a]. "Intravascular stents to prevent occlusion and restenosis after transluminal angioplasty," N. Engl. 1. Med. 316:701-706 (1987).

A second type of stent relies upon thermal expansion. Stents made of nitinol are initially configured as small diameter wires or coils and expand to predetermined shapes with the application of body heat.

A third type of stent is introduced with a balloon catheter. Stents of this type rely on plastic deformation 40
of the metal caused by mechanical expansion when driven by a balloon. Woven stainless steel wire stents are crimped over conventional balloon catheters and then expanded after being positioned at the target site. When the balloon is inflated, the stent is embedded in the vessel wall. Following balloon deflation and removal, the stent remains in place, holding the vessel open if properly placed initially, Palmaz et al., "Expandable intraluminal graft: Preliminary study" Radiology 156:73-77 (1985); Palmaz et al. "Expandable intraluminal grafting," Radiology 160:723-726 (1996); Palmaz et al. "Expandable intraluminal vascular graft: A feasibility study," Surgery 99:199-205 (1986); Palmaz et al. "Expandable intraheparic portacaval shunt stents Early experience in the dog", AJR 145:821-925 (1985), 55 See also generally, Schatz, "Introduction to intravascular stents," Interventional Cardiology Clinics Vol. 6 No. 3 pp 357-372 (1988); Palmaz, 14 Balloon-expandable intravascular stent," AJR 150:1263-1269 (1988); O'Laughlin, "Use of Endovascular Stents in Congenital Heart Disease," Circulation Vol. 83, 1923-39 (1991). However, each of these prior art catheters for delivering stents did so by means of a single balloon angioplasty catheter.

In a variety of congential pediatric heart defects, there is a need for augmented pulmonary blood flow due to pulmonary atresia or stenosis. These defects include Tetralogy of Fallot tricuspid atresia and complex forms of pulmonic stenosis It is advantageous in

2

these applications to maintain a patent ductus arteriosus. In other words, when blood circulation through an infant's heart is blocked or substantially restricted, blood flow from the heart to the lungs is diverted through the ductus arteriosus which is open in the infant's heart only for a relatively short period of time after birth. As the ductus arteriosus closes, as a result of normal heart development, no alternative path then remains to allow for adequate pulmonary circulation in the defective bean. In the worst casts, the infant will eventually become cyanotic and suffocate.

Conventional treatment includes drug treatments by infusions of prostaglandin which inhibits the closing of the ductus arteriosus. This treatment has a disadvantage that the infant must be kept on constant intravenous infusions of the drug until it his become large enough to survive cardiac surgery.

Ultimately, a pulmonary shunt, either through an artificial prosthetic, diversion by a Blalock-Taussig shunt, or central shunt must be performed. These latter procedures involve surgical intervention with inherent anesthesia and perioperative risks.

Therefore, it is desirable to evaluate perfected cardiac catheterization techniques to establish a systematic pulmonary artery communication. What has been attempted in the prior art is the placement of stents in the ductal arteriosus, using conventional angioplasty catheters. See Coe, "Redilating Ductal Stents in Newborn Lambs," 2163 Abstracts from 64th Scientific Sessions 11-543; Moore et al., "Use of an Intravascular Endoprosthesis (stent) to Establish and Maintain Short Term Potency of the Ductus Arteriosus in Newborn Lambs," JACC Vol. 17 No. 2 (1991); and Coe et al., "A Novel Method to Maintain Ductal Potency,'' JACC Vol. 17 No. 2 (1991).

In Coe's study in newborn lambs, catheters were introduced via a cut down in the neck under general anesthesia. A stainless steel stent which was securely mounted on a coronary angioplasty catheter, was introduced into the external jugular vein and manipulated through the right heart under fluoroscopy to place the balloon carefully in the ductus arteriosus. The position of the ductus was previously determined angiographically. 'Me balloon on the catheter was inflated to release the stent in the ductus arteriosus without embolisatiork.

The difficulty with this technique, however, is proper placement in the ductus arteriostis which is a very small and short tubular shunt in the infant's cardiac circulation system near the bean. The stent, although made of stainless steel, is very thin and can be seen only with difficulty under fluoroscopy, which is the only means for determining when and if the stent is properly placed. Improper placement within the ductus arteriosus could result either in failure of the stent to maintain the ductus arteriosus open and/or possible creation of clotting site with resulting complications from embolism.

The inclusion of radiographic markers, either on the stent or the delivery catheter, helps determination of the location of the stent, but provides no assistance in determining whether or not the stent is properly placed with ductus.

Therefore, what is needed is an apparatus and method which can be used in combination with conventional fluoroscopy to allow accurate and secure placement of a stent in the ductus arteriosus of an infant.

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BRIEF SUMMARY OF THE INVENTION

A cardiac catheter for use in maintaining the patency of the ductus arteriosus in infants is provided with two inflatable balloons, a distal end balloon and a stent balloon. Each balloon is independently inflatable. The stent is carried temporarily on the stent balloon and is delivered by the catheter to the site of the ductus arteriosus. Expansion of the stent balloon expands the stent and places it at the target site. The stent balloon is confidently and reliably placed in the ductus arteriosus by first inflating the distal end balloon and withdrawing the catheter until abuts the opening of the ductus Arteriosus through which it has been previously disposed. When this abutment is realized, the stent balloon is necessarily positioned appropriately within the ductus arteriosus While maintaining the inflation of the distal end balloon, the stent balloon is inflated and the stent placed. After placement, both the distal end balloon and stent balloon are deflated and the catheter withdrawn.

More precisely the invention is a catheter for use in maintaining patency of the ductus arteriosus with a stent comprising a catheter body having a proximal end and a distal end. An inflatable distal end balloon is disposed on the distal end of the catheter body. An inflatable stent balloon is disposed near the distal end of the catheter body proximate to the distal end balloon. A mechanism is provided for selectively inflating the distal end balloon and stent balloon. As a result, the stent disposed on the stent balloon is reliably and confidently positioned within the ductus arteriosus and installed therein.

In the illustrated embodiment the distal end balloon is generally spherical when inflated. Whatever shape is chosen for the distal end balloon, it has a shape and size such that, when the distal balloon is inflated, it cannot be withdrawn through the ductus arteriosus.

The stent balloon is generally cylindrical in shape when inflated. The stent balloon has a longitudinal length along the axis of the cylindrical shape approximately equal to the stent.

The stent balloon may further comprise a radiographic opaque marker at one end of the stent balloon, or a pair of radiopaque markers, one marker at each end of the stent balloon.

The mechanism for selectively inflating the distal end balloon and the stent balloon comprises a corresponding plurality of ports communicated through the catheter body. The ports are disposed at the proximal end of the catheter body and communicated through the So catheter body to the distal end balloon and stent balloon at or near the distal end of the catheter body.

The catheter may further include an element for communicating with the distal end of the catheter body from the proximal end of the catheter body. The element for communicating comprises a Pon disposed at the proximal end of the catheter body. A lumen is disposed through the catheter body and a distal end port is defined at the distal end of the catheter body.

The invention is also a method of delivering a stent to the ductus arteriosus of in infant comprises the steps of providing a catheter having a catheter body with a proximal and distal end. The distal end is provided with an inflatable distal end balloon and proximate thereto an inflatable stent balloon. A stent is disposed on the stent balloon so that the stent is temporarily secured to the catheter. The distal end is disposed com-

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pletely through the ductus arteriosus of the infant. The distal end is disposed completely through the ductus arteriosus into an adjacent artery. The distal end balloon is then inflated. The distal end of the catheter is then withdrawn through the ductus arteriosus until the distal end balloon abuts the opening of the ductus arteriosus to thereby prevent further withdrawal. The stent balloon is inflated while maintaining the distal end balloon in an inflated condition and in abutment to the opening of the ductus arteriosus. The inflating stent balloon disposes the stent in the ductus arteriosus. The stent balloon and the distal balloon are then deflated. The catheter is finally removed from the ductus arteriosus. As a result, the stent is confidently and reliably delivered and disposed to the ductus arteriosus.

The method further comprises the steps of providing the stent balloon with at least one radiographic opaque marker to delineate an end of the stent - balloon, and observing the radiographic opaque marker under fluoroscopy to corroborate disposition of the stent within the ductus arteriosus.

The step of providing the stent balloon with a radiographic opaque marker comprises the step of providing the stent balloon with separate radiographic opaque markers at each end of the stent balloon.

The step of inflating the distal end balloon inflates the distal end balloon to a size and shape which prevents its withdrawal through the ductus arteriosus.

The step of inflating the distal end balloon and the stent balloon inflates the balloons through ports provided at the proximal end of the catheter.

Now it can be understood that in general terms the invention is a catheter for maintaining the patency of the ductus arteriosus with a stent in an infant comprising a positioning element for physically determining the position of the catheter within the ductus arteriosus of the infant. A delivery element disposes the stent in the ductus arteriosus to maintain its patency. As a result, the stent is confidently and reliably disposed in the ductus arteriosus without regard to fluoroscopic visibility.

The positioning element comprises a selectively actuatable element configurable into a uniquely determined position relative to position to the ductus arteriosus.

The selectively activatable element is disposed on a distal end of the catheter and is selectively activated when the distal end is disposed through and beyond the ductus arteriosus. The element then is configured after activation to the uniquely determined position relative to the ductus arteriosus.

The delivery element is independently operable from the positioning element. The delivery element comprises a stent for disposition within the ductus arteriosus The stent is temporarily fixed to the delivery element and is selectively disposed within the ductus arteriosus by activation of the delivery element.

The invention may better visualized by now turning to the following drawings wherein like elements are referenced by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. I is a side view of a delivery catheter of the invention used for placement of stents within the ductus arteriosus of in infant.
FIG. 2 is a side view of the distal end of the catheter of FIG. 1 shown in enlarged scale with the stent balloon in an inflated condition.
FIG. 3 is a side view of the distal end of the catheter as shown in FIG. 2 but with the distal end balloon inflated instead of the stent balloon.

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FIG. 4a is a simplified cross-sectional view of an infant's heart showing the catheter of FIGS. 1-3 inserted through the ductus arteriosus and with the distal balloon inflated prior to delivery of the stent.

FIG. 4b is a simplified cross-sectional view of FIG. 5 4a showing the distal end properly positioned in the ductus arteriosus and with the stent balloon inflated to deliver the stent.

The invention and its various embodiments may now be better understood by turning to the following detailed description.

DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS

First the various major elements of the catheter of the 15 invention will be briefly identified. Cardiac catheter 10, as shown in side view of FIG. 1 in the illustrated embodiment, illustrates that the proximal end 12 is fitted with three ports 14, 16 and 18. Ports 14, 16 and 19 are merged into a catheter body 20 through conventional 20 techniques and are coupled to elements at the distal end 22 of catheter 10 described below.

Distal end 12 of catheter 10 has a distal end balloon 24 and behind balloon 24 is a stent balloon 26. Distal balloon 24 when Mated as shown in FIG. 3 in the illustrated embodiment has a diameter of approximately 10 millimeters and is generally spherical or oblate.

Stent balloon 26 in the illustrated embodiment has a length of 7-10 millimeters to form a generally cylindrical balloon of 3-4 millimeters in diameter. Stent balloon 30 26 in one embodiment includes radiographic markers 28 at each end of stent balloon 26 to enhance its fluoroscopic visibility. FIG. 2 shows in enlarged view stent balloon 26 in an inflated condition with distal balloon 24 deflated. FIG. 3 shows the opposite configuration 35 namely stent balloon 26 deflated and distal balloon inflated.

Returning to FIG. 1, catheter 10, which in the preferred embodiment is approximately 60 centimeters in length, communicates port 14 with distal balloon 24. 40 Port 18 is communicated with stent balloon 26. The central port 16 is optionally provided with a hemostasis valve for an end port 30 through distal end 22 of catheter 10 to allow infusions to be injected and specimens to be withdrawn, if desired. In addition, central port 16 45 may provide access for a guidewire to assist in positioning distal tip 22 within the ductus arteriosus

The number of lumens within catheter 10 may cause catheter 10 to be relatively flexible. In such an event, the use of a conventional catheter guide tube (not 50 shown) may be telescopically disposed around catheter 10 and used to &de catheter 10 toward its proper target site. Alternatively, the central lumen and corresponding port 16 may be eliminated along with end port 30 to provide for a stiffer catheter, which may be manipulated without the use of a catheter guide tube.

Distal balloon 24 and stent balloon 26 are inflated through ports 14 and 18 respectively by conventional means, namely inflation by air or by fluid through a syringe or pump.

Turn now to FIGS. 4a and 4b which illustrate the placement of catheter 10 within the ductus arteriosus 32 of an infant's heart 34. Catheter 10 is inserted in the illustrated embodiment through a femoral incision point in femoral artery 36. Using conventional techniques 65 under fluoroscopy, the distal end 22 is guided into ductus arteriosus 32 with both balloons 24 and 26 in a noninflated configuration. While radiopaque markers 28

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assist in the ease of identification of a stent 38, which has been placed over stent balloon 26 and manually crimped thereon to temporarily secure it, the, exact placement of stent 38 relative to ductus arteriosus 32 cannot be accurately and confidently determined under fluoroscopy. Its disposition through the ductus arteriosus is confidently known, but whether it has the correct longitudinal placement within the ductus arteriosus does not show up with reliability under fluoroscopic techniques notwithstanding the existence of radiographic markers 28.

With distal end 22 confidently placed into ductus arteriosus 32, it is inserted well into and through the ductus arteriosus 32 to a point where the surgeon is also confident that distal end 22 has been extended into artery 40 as shown in FIG. 4a

At this point, distal end balloon 24 is inflated through port 14 and while the inflation is retained, catheter 10 is withdrawn until end balloon 24 abuts the opening 42 to ductus arteriosus 32 as shown in FIG. 4b. At the point of abutment, distal balloon 24 prevents further withdrawal of distal end 22 of catheter 10 through ductus artenosus 32. Inasmuch as stent balloon 26 is only one to three millimeters behind the attachment of distal balloon 24 to distal end 22 of catheter 10, appropriate placement of stent 38 within ductus arteriosus 32 is physically guaranteed regardless of what may or may not be visually observable under standard fluoroscopy.

Once the surgeon then feels abutment of distal balloon 24 within ductus arteriosus 32, stent balloon 26 is then inflated, expanding stent 38 in ductus arteriosus 32. After the appropriate expansion of stent 38 has been achieved, both balloons 24 and 26 are then deflated and catheter 10 removed. In some cases, if it is later determined that ductus arteriosus has not been opened sufficiently by stent 38 or becomes subject to constriction for any reason, catheter 10 may be reinserted and confidently repositioned as described above with reinflation of stent balloon 26 to reexpand or clear ductus arteriosus 32.

An example of the use of the invention will help to illustrate its methodology. An experimental animal study was performed using neonatal lambs which were less than 48 hours old. The lambs were sedated, anesthetized and prepared for catheterization, The jugular vein or femoral artery were cannulated percutaneously or via cutdown. Prostaglandin (PGE) was infused to maintain the ductus arteriosus patent. Both right and left heart catheterization was performed using sterile techniques under fluoroscopic guidance. Radiopaque contrast was injected into the aorta to demonstrate the ductus arteriosus.

The stent delivery catheter of the invention was advanced from the femoral artery to the ductus arteriosus. The distal latex balloon was expanded within the pulmonary artery. The catheter was then drawn back through the ductus arteriosus. Because the expanded distal latex balloon cannot be drawn into the smaller ductus arteriosus, it prevented the catheter from being withdrawn any further. At that point, the adjacent, proximal angioplasty stent balloon was inflated to five atmospheres pressure to expand the stent and lodge it within the ductus arteriosus. Both balloons were then rapidly deflated and the catheter withdrawn. The aortagram, right and left bean catheterizations, were then repeated. The catheters were all removed with skin incisions sutured.

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Precautions were taken to prevent dislodgment of the stent from the delivery catheter prematurely by advancing the entire catheter-stent assembly through a sheath to the side of ductus arteriosus or alternatively by crimping the stent onto the balloon.

Subsequent observation of the lambs was made for growth, signs and symptoms of heart failure. Periodic echocardiographic: evaluation of the patency of the stented ductus arteriosus was performed. In each case, successful stent placement without deleterious effects was observed. Subsequent dissection was made to allow growth inspection and microscopy for a thrombus formation, obstruction, endothelialzation, evidence of damage to the aorta, pulmonary artery and ductus arteriosus as well as evaluation of the accuracy of the stent placement. Again no deleterious effects were found and placement was found to be reliable and accurate in each occasion.

Catheterization was repeated prior to dissection to evaluate hemodynamics including relative pulmonary to systematic flow and pulmonary pressures, Again, expected in normal hemodynamics was observed.

Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiment has been set forth only for the purposes of example and that it should not be taken as limiting the invention as defined by the following claims. The following claims are, therefore, to be read to include not only the combination of elements which are literally set forth, but all equivalent elements for performing substantially the same function in substantially the same way to obtain substantially the same result. The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptially equivalent, and also what essentially incorporates the germ of the invention.

I claim:

1. A catheter for use in maintaining patency of the 40 ductus arteriosus comprising:

a catheter body having a proximal end and a distal end;
an inflatable distal end balloon disposed on said distal end of said catheter body;
an inflatable stent balloon disposed near said distal end of said catheter body proximate to said distal end balloon;
means for selectively inflating said distal end balloon and stent balloon; and
an expandable and permanently implantable stent disposed on said stent balloon, said expandable stent assuming a permanent expanded configuration upon inflation of said stent balloon,
whereby said &tent disposed on said stent balloon is 55 adapted to be reliably and confidently positioned within said ductus arteriosus and installed therein.

2. The catheter of claim I wherein said distal end balloon is generally spherical when inflated.

3. The catheter of claim I wherein said distal balloon 60 has a shape and size such that, when said distal balloon is inflated, it assumes a predetermined size, said predetermined size being greater than said ductus arteriosus.

4. The catheter of claim I wherein said stent balloon is generally cylindrical in shape when inflated.

5. The catheter of claim 4 wherein said stent balloon has a longitudinal length along the axis of said cylindrical shape approximately equal to said stent.

6. The catheter of claim I wherein said stent balloon further comprises a radiographic opaque marker at one end of said stent balloon.

7. The catheter of claim 6 wherein said stent balloon has a pair of radiopaque markers, one marker at each end of said stent balloon.

8. The catheter of claim I wherein said means for selectively inflating said distal end balloon and said stent balloon comprises a corresponding plurality of ports communicated through said catheter body, said ports being disposed at said proximal end of said catheter body and communicated through said catheter body to said distal end balloon and stent balloon at or near said distal end of said catheter body.

9. The catheter of claim I further comprising means for communicating with said distal end of said catheter body from said proximal end of said catheter body.

10. The catheter of claim 9 wherein said means for communicating comprises a port disposed at said proxi trial end of said catheter body, a lumen being disposed through said catheter body and a distal end port being defined at said distal end of said catheter body.

11. A method of delivering a stent to the ductus arteriosus of an infant comprising the steps of:

providing a catheter having a catheter body with a proximal and distal end, said distal end being pro vided with in inflatable distal end balloon and proximate thereto an inflatable stent balloon;
disposing a stent on said stent balloon so that said stent is temporarily secured to said catheter;
disposing said distal end through said ductus arteri ousus of said infant, said distal end being disposed completely through said ductus arteriosus into an adjacent artery;
inflating said distal end balloon;
withdrawing said distal end of said catheter through said ductus arteriosus until said distal end balloon abuts the opening of said ductus arteriosus to thereby prevent further withdrawal;
inflating said stent balloon while maintaining said distal end balloon in an inflated condition and in abutment to said opening of said ductus arteriosus, said inflating stent balloon disposing said stent in said ductus arteriosus;
deflating said stent balloon and said distal balloon;
and removing said catheter from said ductus arteriosus,
whereby said stent is confidently and reliably deliv ered and disposed to said ductus arteriosus.

12. The method of claim 11 further comprising the steps of providing said stent balloon with at least one radiographic opaque marker to delineate an end of said stent balloon, and observing said radiographic opaque marker under fluoroscopy to corroborate disposition of said stent within said ductus arteriosus.

13. The method of claim 12 wherein said step of pro viding said stent balloon with a radiographic opaque marker comprises the step of providing said stent balloon with separate radiographic opaque markers at each end of said stent balloon.

14. The method of claim 11 where said step of inflat ing said distal end balloon inflates said distal end balloon to a size and shape which prevents its withdrawal through said ductus arteriosus.

15. The method of claim 11 where in said step of inflating said distal end balloon and said stent balloon, said balloons are inflated through ports provided at said proximal end of said catheter.

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16. A catheter for maintaining the patency of the ductus arteriosus in an infant comprising:

positioning means for physically determining the position of said catheter, said positioning means being adapted to determine said position of said catheter within said ductus arteriosus, of said infant;
an expandable and implantable stent capable of assuming a permanent expanded configuration; and
delivery means for disposing and configuring said stent in said ductus arteriosus to permanently maintain its patency,
whereby said stent is adapted to be confidently and 15 reliably disposed in said ductus arteriosus without regard to fluoroscopic visibility.

17. The catheter of claim 16 wherein said positioning means comprises a selectively actuatable element con-

10

figurable into a uniquely determined position relative to position to said ductus arteriosus.

18. The catheter of claim 17 wherein said selectively activatable element is disposed on a disks end of said catheter and is selectively activated when said distal end is disposed through and beyond said ductus arteriosus, said element then being configured after activation to said uniquely determined position relative to said ductus arteriosus.

19. The catheter of claim 16 wherein said delivery means is independently operable from said positioning means.

20. The catheter of claim 16 wherein said delivery means comprises a stent adapted for disposition within said ductus arteriosus, said stent being temporarily fixed to said delivery means and adapted to be selectively disposed within said ductus arteriosus by activation of said delivery means.

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Patent Practice and Procedure
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Inventors' Comments on Prior Art

Patent No. 5,261,878 has a second balloon at the end; however, the balloon at the end is used to abut the opening of the ductus arteriosus so that the stent is properly positioned. The balloon at the end in this patent is not used to pre-dilate prior to delivering the stent. This catheter also has a very limited use - in the ductus arteriosus in infants. Our catheter can be used in any type of lumen or vessel in a body of any size.