Court Opinion

ID: 3175130
Source: CourtListenerOpinion
Date Created: 2016-02-05 16:03:30.179504+00
Date Added: 2024-06-11T14:49:43.802554
License: Public Domain

United States Court of Appeals
      for the Federal Circuit
               ______________________

               TRIVASCULAR, INC.,
                    Appellant

                          v.

              SHAUN L. W. SAMUELS,
                      Appellee
               ______________________

                     2015-1631
               ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2013-
00493.
                 ______________________

              Decided: February 5, 2016
               ______________________

     DAVID K.S. CORNWELL, Sterne Kessler Goldstein &
Fox, PLLC, Washington, DC, argued for appellant. Also
represented by PAULINE PELLETIER, RICHARD D. COLLER,
III.

   JAMES D. PETRUZZI, Petruzzi Law Firm, Houston, TX,
argued for appellee. Also represented by EVERETT G.
DIEDERIKS, JR., NICHOLAS SPENCER WHITELAW, Diederiks
& Whitelaw PC, Woodbridge, VA.
                 ______________________

Before MOORE, O’MALLEY, and WALLACH, Circuit Judges.
2                             TRIVASCULAR, INC.   v. SAMUELS

O’MALLEY, Circuit Judge.
    TriVascular, Inc. (“TriVascular”) appeals the judg-
ment of the Patent Trial and Appeal Board (“the Board”)
holding that TriVascular failed to satisfy its burden of
proving that the challenged claims of U.S. Patent No.
6,007,575 (“the ’575 patent”) are invalid as obvious. For
the reasons below, we affirm.
                       BACKGROUND
    The ’575 patent claims inventions in the field of in-
traluminal stent technology. One type of intraluminal
stent is a vascular stent. Vascular stents are used to
treat medical conditions wherein a vascular wall is undu-
ly constricted, as in the case of vascular stenosis, or
unduly enlarged, as in the case of aneurysm. Either of
these medical conditions poses an unacceptable risk of
insufficient blood flow or vascular rupture.
                    The Patent in Suit
     The ’575 patent was filed on June 6, 1997, and lists a
sole inventor, Dr. Shaun L.W. Samuels. The ’575 patent
generally claims intraluminal stents that can be affixed to
a vascular wall via the use of “an inflatable and deflatable
cuff” without penetrating the vessel wall. ’575 patent,
col. 6 ll. 47-67. These “inflatable and deflatable cuffs” are
depicted by the number 17 in Figure 1 of the ’575 patent
below, and can be inflated by introduction of a fluid into
each of the “circumferential ridges” 25.
TRIVASCULAR, INC.   v. SAMUELS                                3

Id. at fig. 1.
    Claim 1 of the ’575 patent is illustrative and recites:
    1. An inflatable intraluminal stent adapted to be
    secured to the interior of a tubular structure with-
    in the human body comprising:
    a) an inflatable and deflatable cuff of generally
    hollow cylindrical continuation having a collapsi-
    ble lumen, an inner surface, an inlet, an outlet
    and a friction enhancing outer surface, said fric-
    tion-enhancing outer surface featuring inflatable
    protrusion(s) including at least one circumferential
    ridge disposed about the inflatable cuff, said fric-
    tion-enhancing outer surface engaging the interior
    of the tubular structure without penetration to
    prevent the cuff from moving in a longitudinal di-
    rection with respect to the tubular structure when
    said cuff is in a fully inflated condition;
    b) means for injecting an inflation material into
    said cuff to inflate it; and
    c) a valve integral with the inflatable cuff for per-
    mitting entry of the inflation material from the
    means for injecting and thereafter sealing said
    cuff to prevent deflation.
Id. at col. 6 ll. 47-67 (emphasis added). TriVascular
disputes the Board’s construction of the claim term “cir-
cumferential ridge,” which appears in part (a) of the
claim.
                    Procedural Background
    In 2013, Dr. Samuels sued TriVascular alleging in-
fringement of the ’575 patent. Samuels v. TriVascular
Corp., Case No. 3:13-cv-02261 (N.D. Cal. May 17, 2013).
TriVascular filed a petition for inter partes review (“IPR”)
on August 5, 2013. The Board instituted review on Feb-
ruary 4, 2014. Joint Appendix (“JA”) 168. In its Institu-
4                             TRIVASCULAR, INC.   v. SAMUELS

tion Decision, the Board explained that it was instituting
IPR on the following two grounds: (1) obviousness over
Samuel’s U.S. Patent No. 5,423,851 (“Samuels ’851”) and
U.S. Patent No. 5,423,745 to Todd et al. (“Todd”); and (2)
obviousness over U.S. Patent No. 5,693,088 to Lazarus et
al. (“Lazarus”) and Todd. JA 184. In its Institution
Decision, the Board construed the phrase “circumferential
ridge disposed about the inflatable cuff” to mean “raised
strip disposed circumferentially about the outer surface of
the inflatable cuff.” JA 175-76. Applying its claim con-
struction, the Board then found that “on the present
record,” Samuels had not demonstrated that the Samuels
’851 reference teaches away from the substitution of the
penetrating anchoring barbs taught in the reference, nor
did Samuels establish that removing the barbs would
destroy the objective of the reference. JA 183. According-
ly, the Board explained that TriVascular had established
a reasonable likelihood of success on two potential
grounds.
     The parties subsequently introduced their respective
expert reports regarding the instituted grounds. The IPR
proceeded to trial, and the Board issued a final decision
on December 13, 2014, holding that TriVascular failed to
meet its burden of demonstrating that the challenged
claims were unpatentable over the applied art. JA 24. In
its Final Written Decision, the Board adopted Samuels’
construction of “inflatable protrusions,” as “protrusions
that are themselves inflatable, i.e., expandable by being
filled with fluid.” JA 10. The Board found that, inter alia,
the ’575 patent’s “inflatable protrusions” were not dis-
closed by the prior art, nor would a skilled artisan have
been motivated to combine the prior art in a manner that
would read on the claims of the ’575 patent. The Board
also found that the prior art did not teach the “circumfer-
ential ridges” taught in the ’575 patent at issue, based on
its claim construction at institution, which did not permit
the “circumferential ridges” to be made up of a series of
TRIVASCULAR, INC.   v. SAMUELS                           5

discontinuous inflatable protrusions formed circumferen-
tially about the cuff. JA 18-19.
   After issuance of the Final Written Decision, Tri-
Vascular filed a petition for rehearing, which the Board
denied. JA 34.
   TriVascular timely appealed.       We have jurisdiction
under 28 U.S.C. § 1295(a)(4)(A).
                         DISCUSSION
    TriVascular argues that the Board erred in its con-
struction of the term “circumferential ridges,” and in its
holding that TriVascular failed to demonstrate that the
challenged claims of the ’575 patent are invalid as obvi-
ous. Because we find no reversible error in the Board’s
holdings, we affirm.
                    A. Standard of Review
    When reviewing claim construction by the Board,
“[w]e review underlying factual determinations concern-
ing extrinsic evidence for substantial evidence and the
ultimate construction of the claim de novo.” In re Cuozzo
Speed Techs., LLC, 793 F.3d 1268, 1280 (Fed. Cir. 2015),
cert. granted sub nom., Cuozzo Speed Techs., LLC v. Lee,
No. 15-446, 2016 WL 205946 (U.S. January 15, 2015).
    Obviousness is a question of law based on underlying
facts. In re Gartside, 203 F.3d 1305, 1316 (Fed. Cir.
2000). The Board’s legal conclusion of obviousness is
reviewed de novo; its factual findings concerning extrinsic
evidence are reviewed for substantial evidence. Cuozzo,
793 F.3d at 1280.
    Substantial evidence “means such relevant evidence
as a reasonable mind might accept as adequate to support
a conclusion.” Consol. Edison Co. v. NLRB, 305 U.S. 197,
229 (1938); see In re Morsa, 713 F.3d 104, 109 (Fed. Cir.
2002).
6                            TRIVASCULAR, INC.   v. SAMUELS

                 B. Claim Construction
    TriVascular argues that the Board erred in its claim
construction requiring the term “circumferential ridges”
to mean a “raised strip disposed circumferentially about
the outer surface of the inflatable cuff.” Instead, Tri-
Vascular contends that the Board should have construed
the term to mean “an elevated part of the outer surface
disposed about the inflatable cuff that can be either con-
tinuous or discontinuous.” Appellant’s Br. 3 (emphasis
added). TriVascular argues that the Board’s construction
is inconsistent with the plain meaning of the term “cir-
cumferential ridges.” TriVascular further contends that
the Board erred in failing to apply prosecution history
disclaimer to bar Samuels from arguing for a narrower
construction.
    Samuels responds that the Board correctly interpret-
ed “circumferential ridges” because the plain language
and specification support the construction of continuous
raised ridges disposed radially around the inflatable cuff.
Samuels further asserts that the Board did not err in
rejecting TriVascular’s interpretation of the prosecution
history in construing the term. For the reasons below, we
agree with Samuels.
    1. Broadest Reasonable Interpretation Standard
    In construing claim terms, the Board must determine
the scope of the claims by giving them their broadest
reasonable construction in light of the specification as
they would be interpreted by one of ordinary skill in the
art. Cuozzo, 793 F.3d at 1279-80; compare Phillips v.
AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en
banc). Under a broadest reasonable interpretation, words
of the claim must be given their plain meaning, unless
such meaning is inconsistent with the specification and
prosecution history. Straight Path IP Grp., Inc. v. Sipnet
EU S.R.O., 806 F.3d 1356, 1362 (Fed. Cir. 2015).
TRIVASCULAR, INC.   v. SAMUELS                             7

    While the broadest reasonable interpretation stand-
ard is broad, it does not give the Board an unfettered
license to interpret the words in a claim without regard
for the full claim language and the written description.
In re Suitco Surface, Inc., 603 F.3d 1255, 1260 (Fed. Cir.
2010); see In re Abbott Diabetes Care, Inc., 696 F.3d 1142,
1148-50 (Fed. Cir. 2012) (finding the Patent Office’s
construction unreasonably broad because it was “unrea-
sonable and inconsistent with the language of the claims
and the specification”). Construing individual words of a
claim without considering the context in which those
words appear is simply not “reasonable.” Instead, it is the
“use of the words in the context of the written description
and customarily by those of skill in the relevant art that
accurately reflects both the ‘ordinary’ and ‘customary’
meaning of the terms in the claims.” Ferguson Beaure-
gard/Logic Controls, Div. of Dover Res., Inc. v. Mega Sys.,
LLC, 350 F.3d 1327, 1338 (Fed. Cir. 2003).
            2. The Board’s Claim Construction
     The Board determined that the plain meaning of “cir-
cumferential ridges” under the broadest reasonable
interpretation standard does not encompass discontinu-
ous points arranged in a circular pattern on the surface of
a stent. The Board found support for its construction in
the written description, noting that it described a circum-
ferential ridge as a raised strip “disposed about [the]
circumference of outer surface 23 of inflatable cuff 17.”
JA 175-76 (citing ’575 patent, fig. 1). The Board also
relied on a general purpose dictionary, finding the defini-
tion of “ridge” as “a raised strip (as of plowed ground)” to
be in accord with the specification’s description of a raised
strip. JA 176. Finally, the Board found that TriVascu-
lar’s proposed construction of “circumferential” that would
encompass discontinuous raised sections “does not inform
the meaning of the term ‘circumferential ridge.’” JA 30.
8                            TRIVASCULAR, INC.   v. SAMUELS

    TriVascular alleges that the Board’s construction is
contrary to the plain meaning of the claim term. In
support of its argument, TriVascular asserts that the
Board’s construction is unreasonably narrow in light of
the common definition of a topological “ridge.” TriVascu-
lar points to the Blue Ridge Mountains in the Appalachi-
an Mountain Range, which TriVascular alleges constitute
“discontinuous” protrusions that collectively form the
mountain ridge. Appellant’s Br. 31-32. We find Tri-
Vascular’s arguments to be unpersuasive. First, we note
that TriVascular does not explain why the Board should
have resorted to a topological or cartographical definition
of “ridge,” over a general dictionary definition that is
consistent with both the specification’s teachings and the
remaining claim limitations. And, even resorting to the
topological definition of ridge, TriVascular has failed to
explain why such a topological definition would encom-
pass discontinuous peaks in a mountain range, when
mountain ranges typically consist of adjacent, continuous
mountain peaks. 1 To adopt TriVascular’s definition and
construe “circumferential” to include discontinuous points
would be to adopt an unreasonably broad construction.

    1    TriVascular’s utilization of the Blue Ridge Moun-
tains as an exemplary mountain ridge is particularly
unsupportive of their position. In fact, the National Park
Service has noted that the Blue Ridge Mountains were so
named because “hydrocarbons released into the atmos-
phere by the forest contribute to the characteristic haze
on these mountains and to their distinctive color.” Na-
tional Park Service, Blue Ridge Mountains, Frequently
Asked Questions, at http://www.nps.gov/blri/faqs.htm
(last visited January 8, 2016). The eponymous blue haze
of the mountain range constitutes a continuous ridge
bridging the range’s mountain peaks. Thus the word
“Blue” modifies the term “Ridge”; the term “Ridge” is not
intended to modify the word “Mountains.”
TRIVASCULAR, INC.   v. SAMUELS                            9

See Microsoft Corp. v. Proxyconn, Inc., 789 F.3d 1292,
1300 (Fed. Cir. 2015) (finding that the Board’s construc-
tion of key claim terms was unreasonably broad in light of
the broadest reasonable interpretation standard, and on
that basis vacating and remanding the Board’s finding of
unpatentability). We find the Board’s reliance on the
dictionary definition of ridge when considered in the
context of the written description and plain language of
the claims was proper. 2
            3. Prosecution History Disclaimer
     TriVascular’s other alleged basis of error was that the
Board should have applied prosecution history disclaimer
to prohibit a construction of “circumferential ridges” that
is limited to continuous ridges. Appellant’s Br. 33.
    The same general tenets that apply to prosecution
history estoppel apply to prosecution history disclaimer.
Regents of Univ. of Minnesota v. AGA Med. Corp., 717
F.3d 929, 942 (Fed. Cir. 2013) (drawing a parallel between
prosecution history estoppel barring an equivalence
argument under the doctrine of equivalents and prosecu-
tion history disclaimer barring a position on claim con-
struction under § 112, ¶ 6 that is inconsistent with one
taken before the PTO, and noting that “prosecution histo-

   2    Because TriVascular argues for a broader con-
struction than the one the Board employed rather than a
narrower one, the Supreme Court’s grant of certiorari to
consider the propriety of the broadest reasonable inter-
pretation standard in IPRs will not impact our decision to
affirm the Board’s claim construction and non-
obviousness conclusion here. Cuozzo, 793 F.3d 1268, cert.
granted, Cuozzo Speed Techs., LLC v. Lee, No. 15-446,
2016 WL 205946 (U.S. Jan. 15, 2016). Accordingly, we
need not delay deciding this case pending the Supreme
Court decision in Cuozzo.
10                            TRIVASCULAR, INC.   v. SAMUELS

ry disclaimer may limit the range of equivalent structures
that fall within the scope of a means-plus-function limita-
tion.”). Both doctrines require that the claims of a patent
be interpreted in light of the proceedings in the PTO
during the application process. See Festo Corp. v. Sho-
ketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 733
(2002). As applied to a disclaimer analysis, “the prosecu-
tion history can often inform the meaning of the claim
language by demonstrating how the inventor understood
the invention.” Phillips, 415 F.3d at 1317. “Any explana-
tion, elaboration, or qualification presented by the inven-
tor during patent examination is relevant, for the role of
claim construction is to ‘capture the scope of the actual
invention’ that is disclosed, described, and patented.”
Fenner Invs., Ltd. v. Cellco P’ship, 778 F.3d 1320, 1323
(Fed. Cir. 2015) (citing Retractable Techs., Inc. v. Becton,
Dickinson & Co., 653 F.3d 1296, 1305 (Fed. Cir. 2011)).
Accordingly, disclaimer “ensures that claims are inter-
preted by reference to those ‘that have been cancelled or
rejected.’” Festo Corp., 535 U.S. at 733 (citing Schriber-
Schroth Co. v. Cleveland Trust Co., 311 U.S. 211, 220
(1940)). The party seeking to invoke prosecution history
disclaimer bears the burden of proving the existence of a
“clear and unmistakable” disclaimer that would have been
evident to one skilled in the art. See Elbex Video, Ltd. v.
Sensormatic Elecs. Corp., 508 F.3d 1366, 1371 (Fed. Cir.
2007).
    TriVascular’s argument on prosecution history dis-
claimer proceeds in several steps. First, TriVascular
notes that the examiner initially rejected the claims at
issue by interpreting Samuels ’851 as having “inflatable
protrusions” that form a “circumferential ridge.” Appel-
lant’s Br. 34. Second, TriVascular observes that Samuels
responded to this rejection by (a) stating that Samuels
’851 did not disclose “continuous” circumferential ridges
and (b) introducing an “Amendment B” adding the word
“continuously” to the claim phrase “at least one circum-
TRIVASCULAR, INC.   v. SAMUELS                           11

ferential ridge continuously disposed about said inflatable
cuff.” JA 707. Third and finally, TriVascular notes that
Samuels did not expressly include the term “continuous”
in the final issued claims. TriVascular argues that this
series of events triggers prosecution history disclaimer
that bars Samuels from now arguing for a construction
limited to “continuous” circumferential ridges, which was
not claimed in the final issued claims. Appellant’s Br. 34.
     The Board rejected TriVascular’s prosecution history
disclaimer argument, explaining in relevant part as
follows:
   TriVascular’s arguments focus on the patent ap-
   plicant’s “Amendment B” in isolation, and are un-
   persuasive in view of the subsequent prosecution
   history, which shows that the positions of the Ex-
   aminer and the patent applicant changed follow-
   ing a telephone interview. . . . Ultimately, an
   Examiner’s Amendment was entered deleting
   claim 26 [introduced in Amendment B] and sub-
   stituting a new claim (which issued as patent
   claim 23) and included the limitation “at least one
   circumferential ridge disposed about the inflatable
   cuff” and omitted the “continuously” language of
   Amendment B.
JA 30-31. The Board found it significant that other
amendments were made to the relevant claim, which
apparently convinced the examiner of the patentability of
the claimed invention over the prior art, without regard to
the proposed addition of the word “continuously” to the
claims.
    We find no error in the Board’s conclusion that Tri-
Vascular has failed to meet its burden of demonstrating
the existence of a “clear and unmistakable” disclaimer
that would have been evident to one skilled in the
art. Elbex Video, 508 F.3d at 1371. Though Samuels
offered the “continuously circumferential ridges” limita-
12                            TRIVASCULAR, INC.   v. SAMUELS

tion as one of several possible bases for distinguishing the
prior art, the Examiner never adopted Samuels’ proposed
amendment as a reason for allowing the claims over the
prior art. Since the Examiner ultimately allowed the
claims over the prior art without the proposed amend-
ment, it is difficult to see how a skilled artisan could
interpret the proposed amendment as a disclaimer re-
quired for patentability. Indeed, Samuels offered several
other amendments as possible bases for distinguishing
the prior art: (1) a requirement that the stent use “inflat-
able protrusion(s) without rigid components”; (2) a re-
quirement that the cuff of the stent have “a collapsible
lumen”; and (3) a requirement that the cuff contain a
friction-enhancing outer surface preventing “movement of
the cuff in a longitudinal direction with respect to the
tubular structure.” JA 707-08 (italics added to show
proposed amendments to claims).
    Following the proposed amendment, Samuels and the
Examiner engaged in an interview. Subsequently, Samu-
els submitted new claims “[i]n accordance with the Exam-
iner’s instructions provided during [the] telephone
interview,” and further noted that “the appropriate claims
have been canceled to omit redundancy.” JA 721. The
examiner then allowed the final submitted claims to
issue, over the prior art, without the “continuously cir-
cumferential ridges” limitation. JA 722. During the IPR,
the Board found that this subsequent prosecution history
“shows that the positions of the Examiner and the patent
applicant changed following a telephone interview,”
regarding the allowability of the claims without the
“continuously” limitation. We find no error in the Board’s
finding that the examiner was convinced by these alter-
nate claim amendments rather than the “continuously”
circumferential ridges amendment. This finding is sup-
ported in the record, which shows that the Examiner
entered the alternate amendments, while omitting the
TRIVASCULAR, INC.   v. SAMUELS                           13

“continuously” amendment. JA 721-22. Thus, the Board
did not err in finding that no disclaimer applied.
     TriVascular nonetheless argues that there must be
“written evidence” to contradict an applicant’s concessions
made in an amendment, and that “[w]here the record is
devoid of any written documentation, no inferences can be
made as to what the examiner relied upon or understood.”
Appellant’s Br. 36. TriVascular contends that this propo-
sition flows from three cases, Litton Systems, Inc. v.
Whirlpool Corp., 728 F.2d 1423 (Fed. Cir. 1984), Genzyme
Corp. v. Transkaryotic Therapies, Inc., 346 F.3d 1094
(Fed. Cir. 2003), and Rohm & Haas Co. v. Crystal Chemi-
cal Co., 722 F.2d 1556 (Fed. Cir. 1983). TriVascular’s
reliance on these cases is misplaced.
    First, TriVascular argues that this court explained in
Litton that failure to document the results of an interview
with the examiner estopped the applicant from later
contending that the “prosecution record is not true.”
Appellant’s Br. 37 (citing Litton, 728 F.2d at 1439). Litton
involved a case where an applicant elected to continue
prosecution by filing a continuation application. Litton
then had an examiner interview, the results of which
were not documented. After the examiner interview,
Litton filed an amendment clarifying that the continua-
tion application was a continuation in part (“CIP”).
Subsequently in litigation, Litton attempted to argue
that, in the undocumented examiner interview, the exam-
iner accepted Litton’s explanation that the continuation
application did not contain new matter, and therefore
should be entitled to the continuation application’s filing
date. A review of the prosecution history in each case is
necessarily context-specific. Unlike the present case, the
examiner in Litton accepted Litton’s written filing, which
characterized the application as a CIP. Furthermore, this
court considered the prosecution history as a whole to find
that Litton should be estopped from arguing that the
record was “not true.” In contrast, here the examiner
14                           TRIVASCULAR, INC.   v. SAMUELS

never required the claim amendment upon which Tri-
Vascular hinges its prosecution history disclaimer argu-
ment. Accordingly, Litton does not control the facts of
this case.
    Genzyme is similarly distinguishable. In Genzyme,
the issue was whether an applicant’s attempted last-
minute amendment could omit a limitation that had been
repeatedly emphasized throughout the prosecution histo-
ry. In particular, “the deposit requirement, the specifica-
tion, the applicant’s arguments to distinguish prior art,
the examiner’s responses, and [applicant’s expert’s]
declaration repeatedly stressed that the invention envi-
sioned” inclusion of the claim limitation at issue. Gen-
zyme, 346 F.3d at 1103. This court held that “[a]
clarifying amendment at the last moment could not
negate th[e] extensive public record” in which the appli-
cant had repeatedly argued that a limitation was neces-
sary to distinguish the claimed invention from the prior
art. Id. Similarly, Genzyme supports the Board’s rejec-
tion of prosecution history disclaimer in the present case,
in which the Board considered the proper claim construc-
tion in view of “the complete prosecution history.” JA 31.
    Finally, unlike the present case, Rohm involved a
claim of inequitable conduct based on a patent applicant’s
intentional misrepresentations in certain affidavits.
Rohm, 722 F.2d at 1557. The central issue was whether
the applicant was able to show that it had “cured” its
prior misrepresentations during an examiner interview.
Id. at 1572-73. In Rohm, the applicant provided “lengthy
interview summaries” of the examiner interview, but the
summaries failed to note whether the applicant informed
the PTO “that any misrepresentations had been made or
precisely where they had been made.” Id. We held that
“[s]uch express disclosure was necessary to meet [the
applicant]’s duty, and would have alerted the PTO to the
necessity of reconsidering rejections which had been
withdrawn as a result of those submissions.” Id. Rohm
TRIVASCULAR, INC.   v. SAMUELS                            15

clearly does not control or even inform the question of
prosecution history disclaimer we consider in this case.
    For the above reasons, we find no error in the Board’s
construction of the “circumferential ridges” claim limita-
tion requiring the ridges to be continuous.
                       C. Obviousness
     TriVascular next argues that the Board should have
found the ’575 patent’s claims invalid under the instituted
ground of obviousness over Samuels ’851 in view of Todd.
As explained above, we find no error in the Board’s claim
construction of “circumferential ridges.” For the reasons
below, the Board did not err in finding that TriVascular
failed to satisfy its burden of proving that the challenged
claims of the ’575 patent are invalid as obvious.
     A patent is invalid “if the differences between the sub-
ject matter sought to be patented and the prior art are
such that the subject matter as a whole would have been
obvious at the time the invention was made to a person
having ordinary skill in the art to which said subject
matter pertains.” 35 U.S.C. § 103(a) (2012); see generally
Graham v. John Deere Co., 383 U.S. 1, 17-18 (1966).
Thus, a patent may be found invalid as obvious if “there
are a finite number of identified, predictable solutions,
[and] a person of ordinary skill has good reason to pursue
the known options within his or her technical grasp.”
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007).
Although the KSR test is flexible, the Board “must still be
careful not to allow hindsight reconstruction of references
. . . without any explanation as to how or why the refer-
ences would be combined to produce the claimed inven-
tion.” Kinetic Concepts, Inc. v. Smith & Nephew, Inc., 688
F.3d 1342, 1368 (Fed. Cir. 2012) (emphases added) (inter-
nal quotations omitted).
    The prior art forming the ground of the Board’s deci-
sion being appealed are Samuels ’851 in view of Todd, two
16                           TRIVASCULAR, INC.   v. SAMUELS

references directed at stent technology. Samuels ’851
taught the use of inflatable protrusions containing pene-
trating spikes capable of securing the stent within the
vessel wall. Figures 3 and 4 of Samuels ’851 show the
disclosed protrusions in both inflated and deflated form:

JA 512, Samuels ’851, figs. 3 & 4.
    Todd taught the use of non-penetrating “gripping pro-
tuberances” on the outer surface of the stent. The “grip-
ping protuberances” disclosed in Todd are solid, however,
in contrast to the hollow inflatable ridges taught in the
’575 patent at issue.
TRIVASCULAR, INC.   v. SAMUELS                           17

JA 581, Todd, fig. 7.
    Thus, a key point of distinction between the ’575 pa-
tent and the prior art is that the ’575 patent teaches the
use of inflatable, circumferential ridges that do not pene-
trate the vessel wall.
    TriVascular argues that the Board’s conclusion on
nonobviousness was erroneous because the Board improp-
erly required the references to be physically “bodily incor-
porated” into each other, and because the Board ignored
the state of the art and its predictability. TriVascular
also argues that, contrary to the Board’s findings, a
skilled artisan would have been motivated to combine
Samuels ’851 and Todd by replacing the barbs of Samuels
’851 with the gripping protuberances of Todd to obtain the
desirable result of non-penetrating stent fixation. Thus,
TriVascular argues, it would have been obvious for a
skilled artisan to substitute the inflatable, penetrating
barbs of Samuels ’851 with the noninflatable, nonpene-
trating protuberances of Todd. Appellant’s Br. 45.
     Samuels responds that the Board did not err in con-
cluding that TriVascular failed to carry its burden of
proving invalidity based on the combination of Samuels
’851 and Todd. Samuels contends that TriVascular’s
arguments on obviousness are misguided because the
Board did not require that TriVascular explain how Todd
must be bodily incorporated into Samuels ’851. Samuels
further notes that the Board’s findings that a skilled
artisan would neither have had the motivation to combine
nor a reasonable likelihood of success in combining Samu-
els ’851 with Todd further supports the Board’s conclusion
on nonobviousness. We agree with Samuels that the
Board’s findings are supported by substantial evidence.
     We find no error in the Board’s rejection of TriVascu-
lar’s argument that it would have been obvious to substi-
tute the recessed barbs of Samuels ’851 with the
protuberances of Todd, since TriVascular’s proposed
18                            TRIVASCULAR, INC.   v. SAMUELS

substitution would destroy the basic objective of the
barbs, which is to penetrate surrounding tissue. See JA 18
(Board finding that the “recesses 12 of Samuels ’851
function to project barbs 18 into surrounding tissue when
inflatable balloon cuff 10 is filled fully with fluid.”).
Moreover, in order to meet the claimed limitations, not
only the barbs but also the underlying recesses in Samu-
els ’851 would need to be replaced with inflatable non-
penetrating protrusions. And, it would not have been
obvious to substitute the inflatable barbed recesses with
the non-penetrating protuberances of Todd because the
protuberances taught in Todd were not inflatable, as
recited in the asserted claims. JA 15-17 (“TriVascular,
however, has not provided a declaration, or any other
evidence, to establish that a person of ordinary skill in the
art would understand Todd to disclose protuberances that
are hollow, and themselves inflatable.”).        Thus, the
Board’s findings regarding the lack of a motivation to
combine are supported by substantial evidence.
    TriVascular next contends that the Board’s conclusion
of nonobviousness is inconsistent with the Board’s find-
ings in its Institution Decision, since the Board found that
TriVascular had initially demonstrated a reasonable
expectation of success in demonstrating obviousness.
TriVascular argues that the Board should not have
changed its view of the patent’s validity without clearly
explaining why it had done so. In fact, this misguided
theme pervades TriVascular’s briefs. Contrary to Tri-
Vascular’s assertions, the Board is not bound by any
findings made in its Institution Decision. At that point,
the Board is considering the matter preliminarily without
the benefit of a full record. The Board is free to change its
view of the merits after further development of the record,
and should do so if convinced its initial inclinations were
wrong. To conclude otherwise would collapse these two
very different analyses into one, which we decline to do.
If those determinations were somehow binding with
TRIVASCULAR, INC.   v. SAMUELS                           19

respect to the Board’s final decision, as TriVascular urges,
the patentee’s appeal rights as to that second determina-
tion would be close to illusory. TriVascular’s argument
also fails to appreciate that there is a significant differ-
ence between a petitioner’s burden to establish a “reason-
able likelihood of success” at institution, and actually
proving invalidity by a preponderance of the evidence at
trial. Compare 35 U.S.C. § 314(a) (standard for institu-
tion of inter partes review), with 35 U.S.C. § 316(e) (bur-
den of proving invalidity during inter partes review). The
Board’s findings in its Final Written Decision were thus
not inconsistent with those in its Institution Decision;
they were made under a qualitatively different standard.
    After considering Samuels’ expert’s testimony, the
Board found that, while a skilled artisan might have had
a reasonable expectation of success in replacing the entire
recesses of Samuels ’851 with the protuberances of Todd,
there was an insufficient motivation to substitute just the
barbs of Samuels ’851 with the protuberances of Todd.
The Board’s reasoning is supported by the teachings of
Samuels ’851 and Todd regarding the underlying purpos-
es of the inventions claimed in each reference. First,
Samuels ’851 taught away from substituting only the
barbs, since the barbs were the primary objective of the
reference, allowing the stent to be anchored to the vessel.
Second, replacing just the barbs of Samuels ’851 would
not have satisfied the “circumferential ridge” limitation,
since the barbs were individual, discontinuous points,
rather than a continuous circumferential ridge. Third,
the gripping protuberances of Todd, even if substituted,
would not satisfy the “inflatable protrusions” limitations
of the challenged claims. JA 19-20. TriVascular has not
met its burden of showing that the Board’s findings are
not supported by substantial evidence.
    Though TriVascular asserts that the Board required it
to prove how the references could be physically “bodily
incorporated” within each other, we see no evidence
20                            TRIVASCULAR, INC.   v. SAMUELS

supporting TriVascular’s assertion. Instead, the Board
merely requested that TriVascular explain why it would
have been obvious to replace just the barbs of Samuels
’851 with the circumferential ridges of Todd, in view of
the Board’s findings regarding the stated purposes of each
prior art reference. JA 440-41, Trial Transcript. Accord-
ingly, we find TriVascular’s assertions to be without
merit.
    As discussed above, the Board’s findings regarding
the lack of a sufficient motivation to combine and the lack
of a reasonable expectation of success in combining the
prior art are supported by substantial evidence. In view
of these findings, we see no error in the Board’s conclusion
that TriVascular failed to satisfy its burden of proving
that the challenged claims are invalid.
                       CONCLUSION
     For the above reasons, we find no error in the Board’s
claim construction or its judgment that TriVascular has
failed to meet its burden of demonstrating that the as-
serted claims are invalid as obvious. Accordingly, we
affirm.
                       AFFIRMED