Ex Parte Boulais

Board of Patent Appeals and Interferences

Sep 5, 2008

10421812 (B.P.A.I. Sep. 5, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte DENNIS R. BOULAIS,
Appellant
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Appeal 2008-4290
Application 10/421,8121
Technology Center 1700
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Decided: September 05, 2008
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Before TERRY J. OWENS, CATHERINE Q. TIMM, and
MARK NAGUMO, Administrative Patent Judges.

NAGUMO, Administrative Patent Judge.
DECISION ON APPEAL

1 Application 10/421,812, Expandable Mask Stent Coating Method, filed
24 April 2003. The specification is referred to as the “812 Specification,”
and cited as “Spec.” The real party in interest is listed as Boston Scientific
Scimed, Inc. (Second Amended Appeal Brief, filed 7 December 2007
(“Br.”), 1.)

Appeal 2008-4290
Application 10/421,812

A. Introduction
Dennis R. Boulais (“Boulais”) timely appeals from the final rejection
of claims 1-6, 8-10, and 13. Claims 14-18, the only other pending claims,
have been withdrawn from consideration by the Examiner and are not before
us. We REVERSE.
The claimed subject matter relates to methods of coating selected
areas of stents. Stents are described by the 812 Specification as cylinders
typically having thin walls formed from a non-reactive metal lattice.
(Spec. 5:[10].) According to the 812 Specification, it is often desired to coat
the stents with polymers that can absorb drugs and then release the drugs
when implanted in the body. (Spec. 1[3]-5:[9].) Various processes of
applying the coating are known and these methods are said typically to coat
all surfaces of the stent. (Spec. 6:[12]-[13]. Because the drug-containing
coating may be expensive, and because the coating may interfere with
delivering the stent to the implant site, it is said to be desirable to coat, e.g.,
only the outside of the stent. (Spec. 6:[14]-[15].)
Independent claim 10, which is representative of the issues necessary
to resolve this appeal, is reproduced on the following page from the Claims
Appendix to Boulais’s principal brief on appeal.
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Application 10/421,812

Claim 10:
A method for applying a coating to a selected area of a stent,
comprising the steps of:
[i] placing an expandable masking apparatus comprising
an inflatable balloon and
a coating repelling sleeve
inside the stent,
[ii] inflating the balloon until an outer surface of the
expandable masking apparatus contacts an inner surface
of the stent;
[iii] applying a coating to the stent while the balloon is
inflated; and
[iv] deflating the balloon and removing the expandable
masking apparatus from the stent.
(Claims App., Br. 19; square bracketed labels and indentation added.)
Claim 1 is similar, but includes further limitations on the coating
repelling sleeve. In particular, claim 1 requires that
[ia] the coating repelling sleeve comprises a sheet of material
with the ends of the coating repelling sleeve overlapping
such that the coating repelling sleeve surrounds the
inflatable balloon;
and that, when the balloon is inflated,
[iia] the coating repelling sleeve has sufficient length in the
circumferential direction that its ends remain overlapping
when the balloon is inflated,
wherein limitations [ia] and [iia] are further limitations on the respective
placing [i] and inflating [ii] steps recited in claim 10.
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Appeal 2008-4290
Application 10/421,812

The Rejection
The Examiner has maintained the following rejection:
Claims 1-6, 8-10, and 13 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Sirhan,2 Hillstead,3 and Jung.4
Boulais argues claims 1-6, 8, and 9 as a group that stands or falls
together, and claims 10 and 13 as a second group that stands or falls
together. (Br. 5.) The difference between the two groups relates to the
additional limitations in claim 1 that require the sleeve to be a sheet having
overlapping ends that are long enough to overlap even when the balloon is
inflated. (Br. 15-16; Reply Brief filed 7 March 2008 (“Reply Br.”), 7.)
B. Findings of Fact
Findings of fact (FF) throughout this Decision are supported by a
preponderance of the evidence of record.
The 812 Specification
1. Figure 2, reproduced on the following page, shows an unclaimed
version of the invention:

2 Motasim Sirhan and John Yan, Apparatus and Methods for Variably
Controlled Substance Delivery from Implanted Prostheses, U.S. Patent
Application Publication US 2003/0083646 A1 (1 May 2003), based on
application 10/017,500 filed 14 December 2001.
3 Richard A. Hillstead, Dilatation Balloon within an Elastic Sleeve, U.S.
Patent 5,116,318 (1992).
4 Eugene Jung and Kazuo Sasamine, Balloon Protector, U.S. Patent
5,352,236 (1994).
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Appeal 2008-4290
Application 10/421,812

{812 Specification Figure 2}5

{Figure 2 is said to show a stent and an expandable masking
apparatus}
2. Figure 2 shows a stent 1 into which a balloon 6 has been inserted and
inflated via port 7. (Spec. 8-9:[24].)
3. A summary of the claimed inventions is provided in paragraphs [30]
and [31] of the 812 Specification.
4. Paragraph [30] reads in relevant part:
An additional embodiment of the present method
employs the same balloon expansion step as the forgoing
embodiments, with the addition of an expandable sleeve (not
illustrated) between the outer surface of the balloon and the
inner surface of the stent. Such a sleeve may be formed from a
thin, flat sheet of material such as [[[insert materials:]]]
__________ and ________ that is curled into a cylindrical
shape with overlapping ends [ia], . . . When the balloon is

5 The text in curly braces before and after the Figures is provided to ensure
compliance with section 508 of the U.S. Rehabilitation Act for publication
of this Decision on the USPTO website pursuant to the Freedom of
Information Act. It is not part of the Decision.
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Appeal 2008-4290
Application 10/421,812

expanded in the inflating step, its outer surface presses radially
outward on the sleeve, causing the sleeve diameter to increase
as its overlapping ends slide over one another. The sleeve
continues to expand until its outside surface contacts and masks
the inner surface of the stent. When the deflating and removing
step is performed, the sleeve ends slide over one another to
permit the sleeve diameter to decrease and disengage from the
coated stent. In order to ensure the entire inner surface of the
stent is masked by the sleeve, it should be of sufficient length in
the circumferential direction that its ends remain overlapping
when expanded to its maximum diameter within the stent [iia]
(Spec: 10:[30]; square bracketed editorial instructions original; square
bracketed labels added, showing correspondence with the corresponding
limitations recited in the claims.)
5. According to paragraph [31] of the 812 Specification:
it is preferred that the balloon or the sleeve discourage the
adherence of the coating to their surfaces, both to discourage
the formation of coating ‘bridging’ between the stent lattice
openings and to minimize the amount of costly stent coating
material lost to application on surfaces other than the stent
lattice. The repelling of coating material from the balloon or
sleeve surfaces may be enhanced with materials that discourage
the formation of films.
(Spec:10:[31].)
Sirhan
6. Sirhan describes methods of coating stents with, e.g., drug delivery
materials, wherein the inner “luminal” surface of the stent is shielded from
the coating material by a mandrel (Sirhan 16:[158]) or an expansible balloon
(id. at 16:[160]).
7. Use of the balloon is said to allow easier removal from the stent after
coating. (Sirhan 16:[160].)
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Appeal 2008-4290
Application 10/421,812

8. Sirhan does not describe the use of a sleeve in conjunction with the
balloon.
Hillstead
9. Hillstead describes a dilatation balloon assembly that is used to
implant an endoprosthesis device, such as a stent within a blood vessel.
(Hillstead 1:7-10.)
10. According to Hillstead, a common problem is “the inability of the
deflated balloon to disengage from the stent after the stent has been
expanded.” (Hillstead 2:14-18.)
11. Apparently, on deflation, the balloons can produce flat or ‘wing-like’
configurations that exceed the inflated diameter of the balloon, and thus the
diameter of the expanded stent. (Hillstead 2:18-25.)
12. In addition to the disengagement problem, Hillstead indicates that the
projections can also damage blood vessels. (Hillstead 2:25-30.)
13. Hillstead solves these problems by providing an elastic sleeve around
the conventional balloon assembly. (Hillstead 2:31-34.)
14. According to Hillstead, the balloon expands within the sleeve, and
when the balloon collapses, the elastic sleeve collapses around the collapsed
balloon “forcing it to a small diameter or small lateral extent eliminating the
creation of a ‘blade-like’ or ‘wing-like’ shape in the deflated balloon.”
(Hillstead 2:37-41.)
15. Hillstead does not describe whether the elastic sheets are “coating
repellant.”
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Appeal 2008-4290
Application 10/421,812

Jung
16. Jung teaches elastomeric balloon protectors for a “balloon catheter
comprising an elastomeric sleeve adapted to circumscribe the balloon of a
balloon catheter, the sleeve having an inner diameter smaller than the outer
diameter of the balloon so it exerts continuous compressive force on the
balloon.” (Jung 3:13-18.)
17. In Jung’s words, “[t]he preferred balloon protector 1 has a lubricious
inner surface which permits easy insertion of the balloon into the protector
during manufacture and easy removal before the catheter is used.”
(Jung 4:36-39.)
18. In a particular embodiment, Jung describes a lubricious inner surface
formed from a Teflon™ tube. (Jung 4:45-46.)
19. According to Jung, because Teflon™ is not sufficiently elastomeric,
the tube is slit longitudinally, which allows the tube to be rolled into a
smaller tube that can be easily inserted into an elastomeric sleeve during
manufacture. (Jung 4:46-51.)
20. In Jung’s words, referring to Figure 4, which is reproduced below,

{Jung Figure 4 is said to show a slit Teflon™ tube.}
“[o]nce slit, the two ends 18 and 20 of the Teflon™ tube tend to slide over
each other while the balloon protector is in place.” (Jung 4:51-53.)
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Appeal 2008-4290
Application 10/421,812

The Examiner’s Arguments
The Examiner finds that Sirhan teaches a variety of stent structures
including an open lattice structure on which a deflated balloon might easily
catch. (Ans. 4, citing Sirhan 16:[159].) The Examiner finds further that
Hillstead teaches the use of protective sleeves “to promote ease of
disengagement.” (Id.) The Examiner also finds that Jung teaches that a
protective sleeve of elastomeric material may be lined with a lubricious
material such as silicone or PTFE [polytetrafluoroethylene, sold under the
trademark “Teflon™” by DuPont]. (Id.) In particular, the Examiner finds
that Jung teaches a protective sleeve made from PTFE “that has overlapping
ends that function in the fashion claimed by the applicant.” (Id.) The
Examiner concludes that “it would have been obvious to one skilled in the
art to modify the process of Sirhan so as to employ the protective sleeve of
Jung with the expectation of facilitating disengagement of the balloon from
the stent surface as suggested by Hillstead.” (Id.)
Boulais’s Rebuttal Arguments
Broadly, Boulais argues that Sirhan, Hillstead, and Jung relate to
solving such different problems that the combination requires picking and
choosing features based on hindsight reconstruction using the claimed
subject matter as a road map. (Br. 12.) Thus, according to Boulais, a person
carrying out the Sirhan process of coating stents, which does not occur
within a blood vessel, would not look to Hillstead’s solution to the problem
of avoiding injury to patient blood vessels in which stents are implanted.
(Br. 12-13.)
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Application 10/421,812

Similarly, Boulais argues that “the Examiner provides absolutely no
basis as to why a person of ordinary skill in the art would, after modifying
Sirhan with Hillstead, then turn to Jung.” (Br. 13.) “Under the Examiner’s
rejection,” Boulais continues, “that person has already solved the problem of
removing the balloon from the coated stent in the Sirhan process . . . ” (Id.)
Moreover, Boulais argues, adding only a Teflon™ tube, as taught by Jung,
would contradict Jung, which teaches that the Teflon™ tube is part of
protector sleeve 5, and it is protector sleeve 5 that provides the compressive
force on the balloon that is required by Jung, because the Teflon™ is,
according to Jung, not elastic enough by itself (Br. 14.) Additionally,
according to Boulais, adding only the Teflon™ tube of Jung to Hillstead to
facilitate disengagement of the balloon from the stent would contradict
Hillstead. (Id.) Hillstead, according to Boulais, requires an elastic sleeve,
which the Teflon™ tube described by Jung would not provide. (Id.)
C. Discussion
A prima facie case of obviousness is established only when the
Examiner shows that the combined teachings of the references teach or
suggest all of the limitations of the claimed subject matter. Moreover,
although the substitution of equivalent functional structures is typically
prima facie obvious, the fact finding of functional equivalence and the fact
finding that the person having ordinary skill in the relevant arts would have
recognized a functional equivalence must be supported by probative
evidence in the record.
In the present appeal, with respect to claim 1 and the claims
dependent on claim 1, the critical question is whether, as the Examiner
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Appeal 2008-4290
Application 10/421,812

concluded, it would have been obvious to surround a balloon with the
PTFE6 sleeve taught by Jung, place the PTFE-sheet wrapped balloon inside
a stent, then inflate the balloon until the PTFE sheet contacted the inner
surface of the stent while still completely encompassing the balloon, coating
the stent, and then deflating and removing the balloon and the sheet.
The first problem with the Examiner’s rejection of claim 1 is that the
Examiner’s finding that Jung teaches a “protective sleeve made of PTFE . . .
having overlapping ends that function in the fashion claimed by the
applicant” (Ans. 4) is not sufficient to meet the requirements of claim 1.
Limitation [iia] of claim 1 requires that the sheet be long enough that the
ends of the sleeve surround the inflatable balloon even when the balloon is
inflated. The function of the slit PTFE tube in Jung is not to accommodate
an inflated balloon, but to protect an uninflated balloon. The Examiner has
not directed our attention to any teaching in Jung or Hillstead that supports
the use of a sheet having this property. The next problem concerns the
Examiner’s determination that “[i]t would have been obvious to one skilled
in the art to modify the process of Sirhan so as to employ the protective
sleeve of Jung with the expectation of facilitating disengagement of the
balloon from the stent surface as suggested by Hillstead” (Ans. 4). This
determination is further disconnected from the references because the sleeve
taught by Hillstead must be sufficiently elastic that it can readily expand as
the balloon is inflated, and also squeeze down on the balloon as the balloon
is deflated. (Hillstead 2:37-41; FF14; see also Hillstead 4:36-47, 52-53, and
58-60, describing the elasticity of the sleeve in more detail.) Jung slits the

6 We shall use the generic term, “PTFE,” for the material, except when
quoting the record.
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Application 10/421,812

PTFE tube because it is not sufficiently elastic. (Jung 4:46-51: FF 19.)
Thus, Jung does not provide, with its slit PTFE tube, a functionally
equivalent alternative structure for the elastic sleeve taught by Hillstead.
We conclude that the rejection of claim 1 and claims dependent on
claim 1 must be REVERSED.
The situation regarding claim 10 is similar. The Examiner has not
relied on any disclosure in Jung that provides a reason to use the disclosed
slit PTFE tube as an alternative to the sleeve taught by Hillstead.
Therefore, the combination with Jung is fatal to the obviousness
rejection.
D. Summary
In view of the record and the foregoing considerations, it is:
ORDERED that the rejection of claims 1-6, 8-10, and 13 under
35 U.S.C. § 103(a) in view of the combined teachings of Sirhan, Hillstead,
and Jung is REVERSED.
REVERSED

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Application 10/421,812

MAT

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