Ex Parte Gregorich

Board of Patent Appeals and Interferences

Sep 21, 2011

10864665 (B.P.A.I. Sep. 21, 2011)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
10/864,665 06/09/2004 Daniel Gregorich S63.2-11096-US01 6571
490 7590 09/21/2011
VIDAS, ARRETT & STEINKRAUS, P.A.
SUITE 400, 6640 SHADY OAK ROAD
EDEN PRAIRIE, MN 55344
EXAMINER
SEVERSON, RYAN J
ART UNIT PAPER NUMBER
3731
MAIL DATE DELIVERY MODE
09/21/2011 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte Daniel Gregorich
__________

Appeal 2009-010172
Application 10/864,665
Technology Center 3700
___________

Before: RICHARD E. SCHAFER, SALLY G. LANE, and MICHAEL P. TIERNEY,
Administrative Patent Judges.

SCHAFER, Administrative Patent Judge.

DECISION ON APPEAL

Applicant appeals from the Final Rejection of Claims 1-4, 11-20, 33-39, and
42-45. 35 U.S.C. §§ 6 and 134(a). We affirm.
The Claimed Subject Matter
The claimed subject matter relates to MRI compatible tubular stents such as
those used to prevent or correct flow-preventing constrictions in bodily structures
such as blood vessels. The claimed stents are made of two parts, one arranged
inside the other. Both parts must be free of closed electrically conductive loops
that encircle the longitudinal axis of the stent. Additionally, the contact points
between the inner and outer parts must be “substantially non-conductive” and
“comprise ceramic.”
The absence of electrically conductive loops is said to avoid the
development of electrical eddy currents that develop when a patient having an
implanted insert undergoes an MRI examination. The eddy currents result in
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distortion of the MRI image. Written Description, 1:7-20. While certain known
stent designs, such as helical stents, are said to avoid conductive loops, those stents
are said to be unsatisfactory for other reasons. They provide less compression
resistance and may provide inadequate scaffolding or side branch access compared
to stents having circumferential bands. Written Description, 1:21-29. Applicant’s
two-part design is said to provide a stent that is both MRI compatible and has
“excellent scaffolding, compression resistance and side branch access.” Written
Description, 1: 30-32
Some of Applicant’s claims are directed to the methods of (1) making the
stent and (2) preparing the stent for insertion. The method of making the stent
(Claim 33) requires the steps of providing the two parts, disposing one within the
other and connecting the parts using a non-electrically conductive connection. The
method of preparing the insert for insertion (Claim 42) includes essentially these
same steps and adds the step of placing the device around a catheter.
Representative Claims 1 and 42 are reproduced below (italics added):
1. A tubular insert for a bodily vessel comprising an
unexpanded inner stent engaged to an unexpanded outer stent,
at least a portion of the inner stent disposed within the outer
stent, the outer stent having a longitudinal axis and constructed
so as to be free of any closed loops which are
1) electrically conductive; and
2) disposed about the longitudinal axis such that the
longitudinal axis passes through the closed loop;
the inner stent having a longitudinal axis and constructed so as
to be free of any closed loops which are
1) electrically conductive; and
2) disposed about the longitudinal axis such that the
longitudinal axis passes through the closed loop;
wherein the inner stent is engaged to the outer stent by a
substantially electrically nonconductive connection, the
connection being positioned at a point of overlap between the
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inner stent and the outer stent, the electrically non-conductive
connection comprising ceramic.

42. A method of preparing a tubular medical device for
insertion into a bodily vessel, the method comprising:
a) providing a first stent, the first stent having a
longitudinal axis and constructed so as to be free of any closed
loops which are 1) electrically conductive; and 2) disposed
about the longitudinal axis such that the longitudinal axis passes
through the closed loop;
b) providing a second stent, the second stent having a
longitudinal axis and constructed so as to be free of any closed
loops which are 1) electrically conductive; and 2) disposed
about the longitudinal axis such that the longitudinal axis passes
through the closed loop;
wherein the first stent is engaged to the second stent by a
substantially electrically nonconductive connection, the
connection being positioned at a point of overlap between the
first stent and the second stent;
c) forming the tubular medical device outside the body
vessel by arranging the first and second stents such that at least
a portion of the second stent is disposed within the first stent
and connected to the first stent via a connection which is
substantially electrically non-conductive and such that there
are no closed, substantially electrically conductive loops in the
tubular medical device; and
d) subsequent to the forming step, disposing the tubular
medical device about a catheter.
The Rejections
The examiner entered four rejections relying on a total of five references.1
Each rejection relied upon the combined teachings of the McQuiston and Pacetti

1 The examiner entered the following rejections:
1. Claims 1, 2, 12, 13, 16, 18-20, 33, 37, 39, and 42 under 35 U.S.C. §
103(a) over the combined teachings of McQuiston (U.S. Publication
2003/0114919) and Pacetti (U.S. Patent No. 6,712,844);
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references. The other references are relied upon to teach claimed features which
Applicant has not asserted patentably distinguish the claimed subject matter. Thus,
we limit our discussion of the prior art to McQuiston and Pacetti.
McQuiston
McQuiston describes stents having a polymeric tube and a plurality of
expandable cylindrical metal rings attached to the outside of the tube. McQuiston,
1: ¶ 7. The polymeric tubes
can be made from polyurethanes, polyolefins, polyesters, polyamides,
flouropolymers and their co-polymers, polyetherurethanes,
polyesterurethanes, silicone, thermoplastic elastomer (e.g., C-flex),
polyether-amide thermoplastic elastomer (e.g., Pebax),
fluoroelastomers, fluorosilicone elastomer, styrene-butadiene-styrene
rubber, styrene-isoprene-styrene rubber, polyisoprene, neoprene
(polychloroprene), ploybutadiene [sic], ethylene-propylene elastomer,
chlorosulfonated polyethylene elastomer, butyl rubber, polysulfide
elastomer, polyacrylate elastomer, nitrile rubber, a family of
elastomers composed of styrene, ethylene, propylene, aliphatic
polyearbonate polyurethane, polymers augmented with antioxidents,
polymers augmented with image enhancing materials, polymers
having a proton (H+) core, polymers augmented with protons (H+),
butadiene and isoprene (e.g., Kraton) and polyesterthermoplastic
elastomer (e.g., Hytrel).

2. Claims 3, 4, 11, 14, 34, and 43-45 under 35 U.S.C. § 103(a) over the
combined teachings of McQuiston, Pacetti, and Schmitt (U.S.
Publication 2004/0034403);
3. Claims 15, 35, and 36 under 35 U.S.C. § 103(a) over the combined
teachings of McQuiston, Pacetti, and Summers (U.S. Patent 5,607,445);
and
4. Claims 17 and 38 under 35 U.S.C. § 103(a) over the combined teachings
of McQuiston, Pacetti, and Davidson (U.S. Patent 5,690,670).
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McQuiston, ¶ 48. We take Official notice that such polymers would be considered
to be non-electrically conductive.2 McQuiston’s inner polymeric tube would
therefore be free of any closed loops which are electrically conductive.
McQuiston’s cylindrical outer rings have a longitudinal axis that aligns with
the longitudinal axis of the polymeric tube. McQuiston, Abstract (The stent
includes “cylindrical rings generally aligned on a common axis and disposed
around a polymeric tube”); ¶ 28 (“The stent generally comprises a plurality of
radially expandable cylindrical rings 12 disposed generally coaxially and bonded
to the polymeric tube 13”); Figure 10, item 12 The rings may be made from metal
including stainless steel, titanium, tantalum, nickel titanium, cobalt-chromium,
gold, palladium, platinum and iridium. McQuiston, ¶, 50. We take official notice
that these metals would be understood to be electrically conductive. McQuiston’s
outer metal rings would not be free of any closed loops which are electrically
conductive. However, the overlap or connections between the outer rings and the
inner polymeric tube would be electrically non-conductive due to the
nonconductivity of the polymeric inner tube.
McQuiston also teaches that the outer rings may be secured to the polymer
tube by a variety of techniques including using an adhesive. McQuiston, ¶ 67.
The Differences between McQuiston and the Claimed Subject Matter
Applicant argues that the following limitation, appearing in all claims except
Claim 42, patentably distinguishes the invention over the art:
wherein the inner stent is engaged to the outer stent by a
substantially electrically non-conductive connection, the

2 In this regard we note that McQuiston teaches that the polymeric tube may
also be made from the polymer that has been modified to incorporate a material,
for example, that “generates a magnetic susceptibility artifact of the stent.”
McQuiston, ¶ 48 last sentence.
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connection being positioned at a point of overlap between the
inner stent and the outer stent, the electrically non-conductive
connection comprising ceramic.
App. Br., p. 10. The corresponding limitation, argued with respect to Claim 42, is
somewhat broader in that it does not require that the electrically non-conductive
connection include a ceramic.3
Pacetti
Pacetti relates to MRI compatible stents. Pacetti, Title. Pacetti notes that
stents typically have metal ring elements that create enclosed metal loops. These
loops create electrically conductive paths that interfere with MRI imagery. Pacetti,
3: 10-21. Pacetti says that the currents induced in rings around the circumference
of the stent are the most problematic for MRI imaging. Pacetti, 6:31-35.
Pacetti solves the electrical loop problem by incorporating a non-conductive
material into the ring eliminating the continuous electrically conductive loops.
Pacetti, 3:54-56. Pacetti explains:
The MRI induced oscillating magnetic fields are prevented
from inducing electrical current in the continuous electrical
paths of the stent by the use of non-conducting materials. These
materials are placed in breaks, or electrical discontinuities, in
the stent where they act as electrical insulators.
Pacetti, 4: 42-47. Suitable non-conductive materials are said to be polymers,
adhesives, ceramics and composites, including nitrides, oxides, silicides and
carbides. Pacetti, 7: 37-43.

3 Claim 42 recites in relevant part:
wherein the first stent is engaged to the second stent by a
substantially electrically nonconductive connection, the
connection being positioned at a point of overlap between the
first stent and the second stent; ….
App. Br. 23.
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ANALYSIS
Applicant relies on the differences quoted above to patentably distinguish
these claims. Applicant does not argue any other limitations. We select Claims 1
and 42 as representative. Claims 2-4, 11 -20, 33-39, and 43-45 stand or fall with
Claim 1. 37 CFR § 41.37(c)(1)(vii).
Claims 1-4, 11-20, 33-39, and 43-45
The problem of poor MRI imaging as a result of electrically conductive
closed loops formed in stents during MRI imaging was recognized in the art.
Pacetti, 3: 10-21. Pacetti notes that the problem was particularly acute with respect
to currents induced in rings around the circumference of the stent. Pacetti, 6:31-
35. Pacetti teaches improving MRI imaging by incorporating non-conductive
portions in the stent at locations that will eliminate the conductive loops. One
having ordinary skill in this art would have recognized that that the MRI imaging
of a patient having an implanted stent of the type taught by McQuiston would
suffer image degradation due to the generation of the loop currents in McQuiston’s
metal rings. In light of Pacetti’s teachings, it would have been obvious to
eliminate the conductive loops by introducing electrical discontinuities of non-
conductive material into McQuiston’s metal loops. Pacetti teaches a variety of
non-conductive materials, including ceramics, are suitable for this purpose. It
would also have been obvious to use any of those materials, including the
ceramics, to provide the electrical discontinuities. One having ordinary skill in the
art would have recognized that the discontinuities should be located at places that
would be effective to eliminate current loops. The determination of the appropriate
location for the electrical discontinuities is a straight forward application of the
concept, taught by Pacetti, of using non-conducting regions to eliminate the image
degrading electrical current loops. The determination of the particular locations is,
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therefore, within the skill of the art. It would have been obvious to locate the
discontinuities at any point effective to eliminate current loops.
Applicant argues that the references fail to teach the use of a non-conductive
connection at the point of overlap between the inner and outer part of the stent. To
the extent that a current loop includes the point of overlap between the inner and
outer parts of the stent, it would have been obvious to place an electrically
insulating material at the point of overlap to eliminate the loop. Absent some
showing of criticality in the placement of the discontinuities or a showing of some
particular difficulty in determining the appropriate location, placing the
discontinuity at the point of overlap between the inner and outer stents would have
been obvious.
We affirm the rejections of Claim 1 and Claims 2-4, 11 -20, 33-39, and 43-
45
Claim 42
With respect to this claim, Applicant asserts that the limitation “wherein the
first stent is engaged to the second stent by a substantially electrically non-
conductive connection, the connection being positioned at a point of overlap
between the first stent and the second stent.” App. Br., pp. 13-14. This limitation
is broader than the limitation relied upon with respect to the other claims in that it
does not require that the non-conductive connection include a ceramic material.
Applicant argues that the limitation renders Claim 42 non-obvious for the same
reason as the similar limitation in Claim 1 makes the subject matter of that claim
patentable. App. Br. 13-14. We discussed above why the narrower limitation in
Claim 1 did not render the Claim 1 subject matter non-obvious. For the reasons we
stated above with respect to Claim 1, it would have been obvious to include a non-
conductive connection at any appropriate point necessary to eliminate the electrical
current loops, including the point of overlap of the inner and outer stents.
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We affirm the rejection of Claim 42.
DECISIONS
We affirm the rejections of Claims 1-4, 11-20, 33-39, and 42-45 under 35
U.S.C. § 103(a).
AFFIRMED

KMF