Case: 23-2153 Document: 59 Page: 1 Filed: 07/18/2025

United States Court of Appeals

for the Federal Circuit
______________________

COLIBRI HEART VALVE LLC,

Plaintiff-Appellee

v.

MEDTRONIC COREVALVE, LLC,

Defendant-Appellant
______________________

2023-2153
______________________

Appeal from the United States District Court for the

Central District of California in No. 8:20-cv-00847-DOC-
JDE, Judge David O. Carter.
______________________

Decided: July 18, 2025

______________________

JEFFREY A. LAMKEN, MoloLamken LLP, Washington,

DC, argued for plaintiff-appellee. Also represented by
WALTER H. HAWES, IV, MICHAEL GREGORY PATTILLO, JR.;
CATHERINE MARTINEZ, New York, NY; STEVEN DERRINGER,
MEG E. FASULO, MATTHEW R. FORD, KATHERINE E.
RHOADES, Bartlit Beck LLP, Chicago, IL; JOHN HUGHES,
TAYLOR JAMES KELSON, Denver, CO.

GREGORY A. CASTANIAS, Jones Day, Washington, DC,

argued for defendant-appellant. Also represented by
JENNIFER L. SWIZE; JOSEPH FARLEY, Columbus, OH; KELLY
HOLT RODRIGUEZ, New York, NY; MARK D. FOWLER, DLA
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2 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

Piper LLP (US), Palo Alto, CA; STANLEY JOSEPH

PANIKOWSKI, III, San Diego, CA.
______________________

Before TARANTO, HUGHES, and STOLL, Circuit Judges.

TARANTO, Circuit Judge.
U.S. Patent No. 8,900,294, owned by Colibri Heart
Valve LLC, claims a method, for use in trying to implant
an artificial heart valve to replace a defective valve, that
furnishes a do-over opportunity to the installer to get the
positioning right. In the claimed method, the replacement
valve is only partially deployed from the delivery appa-
ratus but recaptured within the delivery apparatus before
full deployment if it looks like the positioning will be off.
Colibri sued Medtronic CoreValve, LLC, a manufacturer of
replacement heart valves, for infringement—alleging, as
now relevant, that Medtronic was inducing surgeons to
perform the claimed method with Medtronic’s products.
See 35 U.S.C. § 271(b).
The ’294 patent, at the outset of prosecution, included
two independent claims reciting the opportunity-for-do-
over method of partial deployment: one claimed pushing
out the valve from an outer sheath of the delivery appa-
ratus, and one claimed retracting the outer sheath to ex-
pose the valve. During prosecution, the examiner rejected
the latter claim for lack of written description, see 35 U.S.C.
§ 112, and Colibri cancelled it. The patent issued with an
independent claim reciting partial deployment by pushing,
and no claims expressly reciting partial deployment by re-
tracting.
In the district court, Medtronic contended that the ac-
cused use of its product involved partial deployment by re-
tracting, not pushing. At trial, Colibri dropped its
assertion of literal infringement, relying solely on the doc-
trine of equivalents to establish infringement by accused
direct infringers using the accused method with
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 3

Medtronic’s products. The jury, besides rejecting Med-

tronic’s invalidity challenge, found that Medtronic had in-
duced infringement and awarded more than $106 million
in damages to Colibri. Before and after the verdict, Med-
tronic sought judgment as a matter of law (JMOL) on the
ground, among others, that Colibri’s equivalents claim was
barred by prosecution history estoppel, but the district
court denied the motions.
On appeal, Medtronic argues, among other things, that
the district court erred in denying JMOL of noninfringe-
ment. We now conclude that prosecution history estoppel,
based on Colibri’s cancelling of a claim to “retraction” for
partial deployment of the replacement valve and Colibri’s
own recognition of the close linkage of the subject matter
of the cancelled and retained claims, bars application of the
doctrine of equivalents. We therefore reverse the district
court’s denial of JMOL of noninfringement. That is all we
need decide to resolve this dispute over the now-expired pa-
tent.
I
A
The ’294 patent, which expired in January 2022 and is
titled “Method of Controlled Release of a Percutaneous Re-
placement Heart Valve,” relates to artificial heart valves
used to replace diseased or otherwise defective heart
valves. ’294 patent, title; id., col. 2, lines 52–54. Blood
flows through valves in the heart from areas of relatively
high pressure to areas of relatively low pressure. Id., col.
1, lines 31–33, 46–48. Each valve includes “leaflets” (some-
times called “cusps”) spanning the passageway through
which blood flows, with the opening and closing of the leaf-
lets allowing blood to flow only in the proper direction
through the circulatory system. Id., col. 1, lines 48–56; id.,
col. 2, lines 1–28.
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4 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

The ’294 patent describes a replacement heart valve

(200) formed by folding biologically compatible material to
form a tubular portion (210) and a leaflet portion (220), id.,
col. 5, lines 1–7; id., col. 6, lines 62–64, shown in figures 1
and 5.

The leaflets (220) are formed from “a single, continuous,

uncut layer” of material. Id., col. 8, lines 54–60. The tub-
ular portion (210) of the valve (200) is sutured to the inte-
rior of a cylindrical, self-expanding metal stent member
(100), which provides a “semi-rigid” channel through the
diseased valve upon implantation. Id., col. 6, lines 57–67;
id., col. 7, lines 9–11, 27–29, 65–67.
The patent further describes a method of making the
valve and, of key importance here, a method for use in im-
planting a replacement heart valve in which the valve is
partially released and can be recovered if it looks like the
positioning will be incorrect. Id., col. 11, lines 51–62. Fig-
ure 8 depicts an implantation system used in the claimed
method, with the distal end at the bottom and proximal end
at the top, and with the components shown in an expanded
view simply for display purposes. Id., col. 11, lines 40–51.
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 5

A flexible, hollow catheter (400) carrying the stent (100)—

to which the replacement heart valve (200), not shown, is
sutured—is inserted into a blood vessel of the patient, e.g.,
the femoral artery, and advanced through the circulatory
system to the location of the valve that is to be replaced.
Id., col. 11, lines 3–7, 40–48. The catheter (400) includes a
pusher member (420), and, in some embodiments, a move-
able sheath (460) that covers the stent (100) and valve
(shown pulled down for display purposes). Id., col. 11, lines
48–51; id., col. 12, lines 11–14.

Once the catheter is in what seems the desired posi-

tion, the pusher member (420) pushes the stent (100) and
valve (200) towards the distal end of the catheter (410) such
that the stent (100) only partially expands. Id., col. 11,
lines 51–55. At that stage, if the positioning seems incor-
rect, the valve can be “recaptured” (i.e., recovered and re-
turned to its original position within the catheter, with the
stent re-squeezed) and re-deployed once the catheter’s
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6 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

overall location is adjusted. Id., col. 11, lines 55–59. If no

recapture is necessary, the catheter (400) is retracted
slightly, and the pusher member (420) fully pushes out the
stent (100) and valve from the catheter (400). Id., col. 11,
lines 59–62. In embodiments with a moveable sheath
(460), the stent (100) and valve are released by pulling the
moveable sheath towards the proximal end (440) of the
catheter (400), “allowing the self-expending stent to
achieve its full expansion.” Id., col. 12, lines 11–14, 24–27.
Claim 1 is representative and recites as follows:
1. A method of controlled release of a percutaneous
replacement heart valve at a location of a native
heart valve in a patient, the method comprising:
obtaining a replacement heart valve device and a
delivery and implantation system:
the replacement heart valve device including:
a stent member that is collapsible, expand-
able and configured for percutaneous deliv-
ery; and
a valve residing entirely within an inner
channel of the stent member and attached
to a proximal portion of the stent member,
the valve including two to four individual
leaflets made of fixed pericardial tissue;
the delivery and implantation system including:
a pusher member and a moveable sheath,
wherein the pusher member includes a
guide wire lumen, and wherein the movea-
ble sheath includes a lumen configured for
receiving the pusher member;
after the obtaining step, loading the replacement
heart valve device into the lumen of the moveable
sheath such that the replacement heart valve
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 7

device is collapsed onto the pusher member to re-

side in a collapsed configuration on the pusher
member and is restrained in the collapsed configu-
ration by the moveable sheath;
after the loading step, advancing the delivery and
implantation system transluminally over a guide
wire within the patient to position the replacement
heart valve device for deployment within the pa-
tient at the location of the native heart valve;
after the advancing step, partially deploying
a distal portion of the replacement heart
valve device within the patient by pushing
out the pusher member from the moveable
sheath to expose the distal portion of the re-
placement heart valve device;
after the partially deploying step, restraining the
replacement heart valve device so that it does not
pop out and is held for controlled release, with a
potential that the replacement heart valve device
can be recovered if there is a problem with position-
ing; and
after the restraining step, recovering the distal por-
tion of the replacement heart valve device within
the moveable sheath that was exposed in order to
address a problem with the position of the replace-
ment heart valve device within the patient.
Id., col. 13, line 38 through col. 14, line 37 (emphasis
added).
B
Medtronic sells replacement heart valves, broadly re-
ferred to as the “Evolut” line of products. The Evolut prod-
ucts include a self-expanding metal stent and a
replacement heart valve with three leaflets sutured to a cy-
lindrical “inner skirt.” J.A. 26579, 26676, 28875.
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8 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

Importantly here, the Evolut products can be “recaptured”

during implantation, if necessary. See, e.g., J.A. 26514–15
(describing recapture process).
The implantation of the Evolut products involves ad-
vancing a catheter containing the replacement heart valve
through the patient’s circulatory system. J.A. 26580–81.
The catheter includes an inner member disposed inside the
replacement heart valve and stent, and a moveable sheath
(also called a capsule) that covers the replacement heart
valve and stent. J.A. 22866–68. It is illustrated in the rec-
ord as follows (with the distal end to the left):

J.A. 27612. A deployment knob (located on a portion of the

catheter outside the patient’s body) controls the position of
the moveable sheath relative to the replacement heart
valve and stent: Rotating the deployment knob in one di-
rection retracts the moveable sheath and uncovers (i.e.,
partially or fully deploys) the replacement heart valve and
stent, while rotating in the other direction re-covers (i.e.,
recaptures) the replacement heart valve and stent. J.A.
22867–68; see also J.A. 21133, line 1 through J.A. 21135,
line 7 (Colibri’s witness discussing deployment mecha-
nism).
II
A
In May 2020, Colibri sued Medtronic for infringement
of the ’294 patent in the United States District Court for
the Central District of California. Complaint at 16–21,
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 9

Colibri Heart Valve LLC v. Medtronic CoreValve LLC, No.

20-cv-00847 (C.D. Cal. May 4, 2020), ECF No. 1 (Com-
plaint); see also First Amended Complaint at 16–22, Colibri
Heart Valve LLC v. Medtronic CoreValve LLC, No. 20-cv-
00847 (C.D. Cal. June 12, 2020), ECF No. 30 (First
Amended Complaint). 1 Colibri asserted direct infringe-
ment (literally and under the doctrine of equivalents) un-
der 35 U.S.C. § 271(a), contributory infringement under
§ 271(c), and inducement of infringement under § 271(b).
Complaint at 18–19; First Amended Complaint at 18–19.
Colibri later abandoned its allegations of direct and con-
tributory infringement, proceeding only with its allega-
tions of inducement of infringement. Medtronic raised
affirmative defenses of invalidity and prosecution history
estoppel in its answer. Answer at 10, Colibri Heart Valve
LLC v. Medtronic CoreValve LLC, No. 20-cv-00847 (C.D.
Cal. Apr. 13, 2021), ECF No. 114.
A special master appointed by the district court, after
conducting claim-construction proceedings, issued a recom-
mendation to the court on February 11, 2021. Report and
Recommendation on Claim Construction at 1, Colibri
Heart Valve LLC v. Medtronic CoreValve LLC, No. 20-cv-
00847, 2021 WL 4437737, at *1 (C.D. Cal. Feb. 11, 2021),
ECF No. 97 (Claim Construction). The parties disputed the
construction of one term relevant here: “pushing out the
pusher member from the moveable sheath.” Id. at *20–22.
Colibri proposed that the phrase meant a “pushing force is
applied to the pushing member in a direction outwards
from the moveable sheath,” and Medtronic proposed the
phrase meant “pressing against the pusher member with a

1 Colibri also asserted infringement of U.S. Patent

No. 9,124,739. Complaint at 16–17; First Amended Com-
plaint at 16–18. The district court granted summary judg-
ment of noninfringement of the ’739 patent, and Colibri did
not cross-appeal.
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10 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

force that moves the pusher member out of the moveable

sheath.” Id. at *20. The special master recommended that
the district court adopt Medtronic’s proposed construction,
reasoning that the claimed “pushing out” limitation is not
just a matter of the force’s direction but “requires move-
ment of the pusher member such that the replacement
heart valve moves outward from the sheath to at least some
degree.” Id. at *26. The district court adopted the recom-
mended claim construction. Order at 1, Colibri Heart
Valve LLC v. Medtronic CoreValve LLC, No. 20-cv-00847,
2021 WL 4439091, at *1–2 (C.D. Cal. May 19, 2021), ECF
No. 119.
B
After claim construction, both parties moved for sum-
mary judgment: Colibri for partial summary judgment of
no invalidity, and Medtronic for summary judgment of in-
validity and noninfringement. Medtronic argued, among
other things, that Colibri’s assertion of infringement of
claim 1 under the doctrine of equivalents was barred by
prosecution history estoppel. In particular, it argued that
Colibri’s cancelling during prosecution of then-claim 39—
while retaining then-claim 34 (which issued as claim 1)—
“precludes Colibri from asserting that, under the [doctrine
of equivalents], partial deployment and recovery of the
valve is performed by retracting the sheath.” J.A. 3164
(emphasis added). Cancelled claim 39 recited:
A method of controlled release of a percutaneous
replacement heart valve in a patient where a bio-
prosthetic heart valve is indicated, comprising:
providing a replacement heart valve device and a
delivery and implantation system;
the replacement heart valve device including:
a stent member that is collapsible, expand-
able and configured for percutaneous deliv-
ery; and
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 11

a valve attached to the stent member. the

valve including two to four individual leaf-
lets;
the delivery and implantation system including:
a pusher member and a moveable sheath,
wherein the pusher member includes a lu-
men for receiving a guide wire, wherein the
moveable sheath includes a lumen config-
ured for receiving the pusher member, and
wherein the replacement heart valve de-
vice is collapsed onto the pusher member to
reside in a collapsed configuration on the
pusher member and is restrained in a col-
lapsed configuration by the moveable
sheath;
after the providing step, advancing the delivery
and implantation system over the guide wire
within the patient to position the replacement
heart valve device for deployment within the pa-
tient;
after the advancing step, partially deploying
the replacement heart valve device within
the patient by retracting the moveable
sheath to expose a portion of the replacement
heart valve device; and
after the partially deploying step, recovering the
portion of the replacement heart valve device
within the moveable sheath that was exposed in or-
der to address a problem with the position of the
replacement heart valve device within the patient.
J.A. 23140–41 (emphasis added).
The special master recommended that the court reject
Medtronic’s prosecution-history-estoppel argument. Re-
port and Recommendation on Summary Judgment at 33–
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12 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

38, Colibri Heart Valve LLC v. Medtronic CoreValve LLC,

No. 20-cv-00847 (C.D. Cal. July 26, 2021), ECF No. 202; see
also Redacted Report and Recommendation at 33–38,
Colibri Heart Valve LLC v. Medtronic CoreValve LLC, No.
20-cv-00847 (C.D. Cal. Aug. 10, 2021), ECF No. 220-1
(Summary Judgment Recommendation). The special mas-
ter reasoned that cancelled claim 39 “was an independent
claim separate from” retained claim 34 (issued claim 1) and
Medtronic “d[id] not show that . . . [Colibri] cancelled claim
39 in favor of purs[u]ing a limitation that already appeared
in [claim 1] . . . or that [Colibri] added or amended any
claims directed to this limitation.” Summary Judgment
Recommendation at 37. In other words, cancelled claim 39
and retained claim 34 (issued claim 1) were clearly differ-
ent, i.e., separate and distinct. The special master also dis-
tinguished Colibri’s “asserted equivalent” as “not merely
retraction” but instead a combination of pushing and re-
tracting, so “[t]he asserted equivalent . . . differs from what
was set forth in the cancelled claim.” Id. at 37–38. The
district court adopted the special master’s recommendation
regarding the “pushing out” limitation and denied sum-
mary judgment. Order at 12–13, Colibri Heart Valve LLC
v. Medtronic CoreValve LLC, No. 20-cv-00847 (C.D. Cal.
Nov. 15, 2021), ECF No. 275.
C
A jury trial on the issues of invalidity and infringement
began on January 31, 2023. Mid-trial, Colibri abandoned
its theory that Medtronic literally infringed the ’294 pa-
tent, arguing instead that, under the doctrine of equiva-
lents, Medtronic’s partial-deployment method (applying a
force to hold the stent in place while retracting the movea-
ble sheath) is equivalent to the claimed partial-deployment
method (applying a force to push the stent out of the move-
able sheath). During the jury trial, Medtronic filed two mo-
tions for JMOL, see Fed. R. Civ. Pro. 50(a), seeking, among
other things, judgment of no equivalents infringement on
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 13

the ground of prosecution history estoppel. The district

court did not rule on the Rule 50(a) motions.
The jury found that Medtronic induced infringement of
claims 1–3 of the ’294 patent and that Medtronic had not
proven that those claims were invalid, and it awarded more
than $106 million in damages to Colibri. J.A. 20–23. After
the jury issued its verdict, Medtronic filed a renewed mo-
tion for judgment as a matter of law under Fed. R. Civ. P.
50(b) and a motion for new trial under Fed. R. Civ. P. 59.
The district court denied the motions on June 8, 2023, re-
jecting Medtronic’s prosecution history estoppel argument
“for the same reasons set forth by the Court during sum-
mary judgment proceedings.” J.A. 4.
The district court entered final judgment on June 16,
2023, J.A. 16–17, and Medtronic timely appealed, J.A. 205.
We have jurisdiction under 28 U.S.C. § 1295(a)(1).
III
Medtronic challenges four rulings of the district court:
(1) the denial of JMOL of invalidity, Medtronic Opening Br.
at 30–40; (2) the denial of JMOL of noninfringement, id. at
41–53; (3) the denial of JMOL of no active inducement, id.
at 53–58; and (4) the denial of Medtronic’s motion for a new
trial on damages, id. at 59–71. It is undisputed that, if we
reverse the denial of JMOL of noninfringement, we need
not reach Medtronic’s other challenges, including the inva-
lidity challenge to this expired patent. Oral Arg. at 2:23–
2:45, https://oralarguments.cafc.uscourts.gov/default.aspx
?fl=23-2153_05052025.mp3.
We follow the Ninth Circuit’s de novo standard for re-
view of the district court’s JMOL decision. See TEK Global,
S.R.L. v Sealant Systems International, Inc., 920 F.3d 777,
783 (Fed. Cir. 2019) (citing Wechsler v. Macke International
Trade, Inc., 486 F.3d 1286, 1290 (Fed. Cir. 2007)). The
JMOL standard itself, regarding fact issues, requires def-
erence to the factfinder: JMOL is not to be granted unless
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14 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

“the evidence, construed in the light most favorable to the

nonmoving party, permits only one reasonable conclusion,
and that conclusion is contrary to the jury’s verdict.”
TVIIM, LLC v. McAfee, Inc., 851 F.3d 1356, 1362 (Fed. Cir.
2017) (quoting Harper v. City of Los Angeles, 533 F.3d 1010,
1021 (9th Cir. 2008)). Prosecution history estoppel, how-
ever, is a matter of law, not of fact, and it is decided de novo
on appeal under our own circuit’s law on this patent-law
issue. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki
Co., 344 F.3d 1359, 1367–68 (Fed. Cir. 2003) (en banc).
Although Medtronic challenged the district court’s de-
nial of JMOL of noninfringement on several grounds, we
address and decide only on one of those grounds—prosecu-
tion history estoppel. We conclude that Colibri’s cancella-
tion during prosecution of claim 39, which recited
“retracting the moveable sheath,” bars Colibri from assert-
ing infringement under the doctrine of equivalents under
the theory that a combination of applying a pushing force
to the pusher member while retracting the moveable
sheath (what Medtronic’s device does) is equivalent to, i.e.,
not substantially different from, “pressing against the
pusher member with a force that moves the pusher mem-
ber outward from the moveable sheath” (what claim 1 re-
quires). Medtronic Opening Br. at 46–51; see Claim
Construction at *26; see also Colibri Response Br. at 47
(discussing equivalence theory). That conclusion suffices
for reversal.
A
As an initial matter, we reject Colibri’s assertion that
we should not consider Medtronic’s prosecution-history-es-
toppel argument because Medtronic waived it before the
district court. Colibri Response Br. at 45. Colibri’s waiver
argument rests on Medtronic’s statement in a pre-trial
memorandum filed on January 3, 2022, under the heading
“Abandonment of Issues,” that “Medtronic is not pursuing
the Fifth Affirmative Defense of Prosecution History
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 15

Estoppel.” J.A. 13659. Medtronic filed this pre-trial mem-

orandum in accordance with Local Rule 16-4.6 of the Cen-
tral District of California, which requires that the parties
“identify any pleaded claims or affirmative defenses which
have been abandoned.” In the circumstances of this case,
we do not deem Medtronic to have waived the JMOL argu-
ment based on prosecution history estoppel, an argument
the district court itself reached on the merits in denying
JMOL without suggesting that there was a waiver.
First, Medtronic’s statement, though poorly worded,
can reasonably be understood to be saying only what it was
not pursuing at trial, i.e., that Medtronic would not repeat
its prosecution-history-estoppel argument before the jury,
as this argument had already been rejected at summary
judgment and involved a question of law on which no facts
needed to be proved at trial. Indeed, Medtronic in the same
pre-trial memorandum disclaimed waiver, stating: “The
[c]ontentions below are based on Medtronic’s current un-
derstanding of the parties’ claims in light of the Technical
Special Master’s Reports and Recommendations on Sum-
mary Judgment . . . . Medtronic’s inclusion of the [c]onten-
tions below does not constitute a waiver or concession of
any aspect of Medtronic’s objections or arguments made in
connection with those orders, not does it constitute a
waiver of Medtronic’s right to appeal the same.” J.A.
13637. Medtronic made a similar disclaimer in its trial
brief. J.A. 18581–82.
Second, when Medtronic later made a Rule 50(a) mo-
tion for JMOL during trial, Medtronic explicitly made its
prosecution-history-estoppel argument. J.A. 18727. And
Colibri, responding, did not assert that Medtronic had
abandoned the argument, instead urging the court to reject
the argument solely on the merits. J.A. 18751. That re-
sponse by Colibri comes within the principle that a waiver
argument may be forfeited “by addressing the claim on the
merits without also making a waiver argument.” Norwood
v. Vance, 591 F.3d 1062, 1068 (9th Cir. 2010).
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16 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

Third, Colibri asserted waiver for the first time in its

opposition to Medtronic’s Rule 50(b) motion, even though it
had the opportunity to do so when responding to Med-
tronic’s Rule 50(a) motions. Colibri’s Opposition to Med-
tronic’s Renewed Motion for Judgment as a Matter of Law
at 8, Colibri Heart Valve LLC v. Medtronic CoreValve LLC,
No. 20-cv-00847 (C.D. Cal. May 11, 2023), ECF No. 479
(“The Court should hold Medtronic to its voluntary aban-
donment of its prosecution history estoppel defense and
find this issue waived.”). But even then, Colibri did not
establish any prejudice from the pretrial statement fol-
lowed by the raising of this issue of law in seeking JMOL.
And the district court, in then ruling on the Rule 50(b) mo-
tion, did not agree with Colibri’s waiver contention. In-
stead, it directly addressed the merits, with no suggestion
that the estoppel argument had been waived. See J.A. 4.
Whether that course reflected the district court’s reading
of the pre-trial statement, reliance on Colibri’s failure to
raise waiver in opposing the Rule 50(a) motion, or exercise
of any available discretion to reach the merits in the ab-
sence of any prejudice in these circumstances, we see no
justification for us now to reject Medtronic’s prosecution-
history-estoppel argument as waived by its pre-trial state-
ment.
B
On the merits of prosecution history estoppel, Med-
tronic argues that the district court erred by concluding
that Colibri’s asserted equivalent is quite distinct and sep-
arate from what was recited in cancelled claim 39 and that
Colibri’s cancellation of claim 39 was not a narrowing
amendment. Medtronic Opening Br. at 47–48. We agree
with Medtronic on those two related points, relying on
Colibri’s own recognition, in its affirmative case for finding
equivalents, of the substantive linkage between the can-
celled and retained claims. And because Colibri makes no
argument against prosecution history estoppel except that
the presumption of estoppel is inapplicable at the
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 17

threshold, i.e., it makes no argument that this case comes

within an exception when the presumption of estoppel ap-
plies or that the scope of particular narrowing does not jus-
tify estoppel, we hold that estoppel bars equivalents
infringement here.
1
We begin with the district court’s conclusion that the
asserted equivalent (i.e., the implantation method of Med-
tronic’s Evolut system) differs distinctly from what was re-
cited in cancelled claim 39. Colibri asserts that claim 39
did not require pushing the inner member—only retracting
the moveable sheath—whereas Medtronic’s Evolut devices
require both pushing and retracting. Colibri Response Br.
at 47; see also id. at 47–48 (“Pushing while retracting is not
‘precisely what was recited in claim 39.’ Pushing appears
nowhere in claim 39.”). The district court agreed with
Colibri that, because Colibri’s “asserted equivalent is not
merely retraction,” the “asserted equivalent . . . differs from
what was set forth in the cancelled claim.” Summary Judg-
ment Recommendation at 37–38 (emphasis added).
Colibri’s own affirmative theory of equivalence, how-
ever, hinges on what Colibri calls “simple physics,” Colibri
Response Br. at 11, 38, and “basic physics,” id. at 56, re-
quiring that opposing forces (i.e., pushing and retracting)
be applied to deploy the valve and stent from the moveable
sheath. Colibri repeatedly asserted, before both this court
and the district court, that the relevant artisan would un-
derstand that pushing necessarily accompanies retracting:
“[B]ecause of the radial force the stent exerts on the inside
of the sheath, there’s ‘[a]bsolutely’ no way to deploy the re-
placement heart valve without ‘applying opposing forces.’” 2

2 We do not rely on Medtronic’s argument based on

the “comprising” language of cancelled claim 39. See Med-
tronic Opening Br. at 47–48.
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18 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

Id. at 59 (second alteration in original) (quoting J.A. 21292,

lines 20–24); see also J.A. 21077, lines 3–18 (Colibri’s wit-
ness explaining that, because the stent is self-expanding,
“we have to have something that’s going to contact and take
hold of that stent so that we can move it”).
Claim language present in both retained claim 34 (is-
sued claim 1) and cancelled claim 39 further indicates that
the relevant artisan would know that pushing necessarily
accompanies retraction—that, in Colibri’s words, “basic
physics require pushing.” See Colibri Response Br. at 56.
Both claims recite that “the replacement heart valve device
. . . is restrained in the collapsed configuration by the
moveable sheath.” ’294 patent, col. 14, lines 12–15 (claim
1); J.A. 23140 (claim 39). This language indicates that the
stent is held in place by the moveable sheath and will move
with the moveable sheath in the absence of a pushing force
on the stent (or something holding the stent, like the
pusher member).
We conclude, accordingly, that the district court and
special master were incorrect that Colibri’s asserted equiv-
alent distinctly “differs from what was set forth in” claim
39 such that the substance dropped when cancelling claim
39 is quite separate from the substance of retained claim
34 (issued claim 1). Summary Judgment Recommendation
at 38. Colibri’s assertions before this court and the district
court, coupled with the surrounding claim language, make
clear that pure retraction of the moveable sheath would re-
sult in retraction of the stent and valve as well—the only
way to deploy (i.e., separate) the stent and valve from the
moveable sheath is to simultaneously exert a pushing force
on the inner member holding the stent and valve. A coun-
tervailing pushing force is therefore necessary to both
Colibri’s asserted equivalent and the deployment method
described by claim 39.
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 19

2
We similarly agree with Medtronic’s second argument,
which is closely related to the first—that Colibri’s cancel-
ling of claim 39 in favor of pursuing limitations that al-
ready appeared in retained claim 34 (issued claim 1) was a
narrowing amendment giving rise to prosecution history
estoppel. Medtronic Opening Br. at 47–48. Narrowing is
a prerequisite to prosecution history estoppel: “If the
amendment was not narrowing, then prosecution history
estoppel does not apply.” Festo, 344 F.3d at 1366. But the
required narrowing is not a purely formal matter of alter-
ing a single claim’s terms; it can exist, and we conclude
here does exist, as a substantive matter based on cancelling
a closely related claim involving such intertwined termi-
nology that cancelling one claim necessarily communicated
that the scope of the other claim had narrowed.
As just explained, Colibri cancelled claim 39, which re-
cited partial deployment by retracting and necessarily in-
volved applying a pushing force to the inner member in
order to achieve that retraction. That cancellation bears
on what can be covered under the doctrine of equivalents
by claim 1 because a relevant artisan would understand
the close basic-physics relationship of the cancelled and re-
tained claims. The portions of the two claims that recite
the partial-deployment step in question are substantially
similar—both recite exposing the valve, the only difference
is that then-claim 34 (issued claim 1) recites doing so by
“pushing” while claim 39 recites “retracting”:
after the advancing step, partially deploying a dis-
tal portion of the replacement heart valve device
within the patient by pushing out the pusher
member from the moveable sheath to expose the
distal portion of the replacement heart valve device
’294 patent, col. 14, lines 21–25 (emphasis added) (claim 1);
see J.A. 23140 (then-claim 34).
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20 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

after the advancing step, partially deploying the re-

placement heart valve device within the patient by
retracting the moveable sheath to expose a por-
tion of the replacement heart valve device;
J.A. 23141 (emphasis added) (claim 39).
The district court’s reasons for rejecting such a rela-
tionship between the cancelled subject matter and claim 1
rely on formalities: that then-claim 34 (issued claim 1) and
then-claim 39 were separate independent claims, and that
Colibri did not “add[] or amend[] any claims directed to” the
pushing limitation. Summary Judgment Recommendation
at 37. That rationale, however, makes an entirely formal
point, requiring a formal claim relationship between the
cancelled and allowed claims (e.g., independent and de-
pendent). If formalities are not determinative, however,
the rationale does not justify denying estoppel here. As al-
ready indicated, the relevant artisan would understand
that claim 1 (reciting only pushing) and claim 39 (reciting
only retracting) are not unrelated to each other but, in fact,
are closely related as a substantive matter, so giving up one
communicates a narrowing message about the one re-
tained.
Governing law precludes making formalities determi-
native, to the exclusion of substantive relationships that
would be understood by relevant readers. “Estoppel is a
‘rule of patent construction’ that ensures that claims are
interpreted by reference to those ‘that have been cancelled
or rejected.’” Festo Corp. v. Shoketsu Kinzoku Kogyo Ka-
bushiki Co., 535 U.S. 722, 733 (2002) (quoting Schriber-
Schroth Co. v. Cleveland Trust Co., 311 U.S. 211, 220–21
(1940)). That principle by its terms does not limit estoppel
to situations in which the issued, asserted claim itself was
amended, though the claim in Festo itself had been
amended. See Festo, 344 F.3d at 1371–72 (discussing pa-
tentee’s narrowing by adding limitations). And the Court
in Festo used additional language not strictly limiting
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 21

estoppel to the amendment of a particular claim, but in-

stead tailoring the inquiry to the scope of the claims of the
patent as a whole, pre- and post-amendment. See, e.g.,
Festo, 535 U.S. at 736 (“Estoppel arises when an amend-
ment is made to secure the patent and the amendment nar-
rows the patent’s scope.” (emphasis added)); id. at 740
(“Where the original application once embraced the pur-
ported equivalent but the patentee narrowed his claims to
obtain the patent or to protect its validity, the patentee
cannot assert that he lacked the words to describe the sub-
ject matter in question.” (emphasis added)). 3

3 The Supreme Court in Festo relied on the reasoning

of Schriber-Schroth, which explained the underlying ra-
tionale of prosecution history estoppel in a validity context
not directly involving that doctrine. For example, the
Court in Schriber-Schroth said: “Where the patentee in the
course of his application in the patent office has, by amend-
ment, cancelled or surrendered claims, those which are al-
lowed are to be read in the light of those abandoned and an
abandoned claim cannot be revived and restored to the pa-
tent by reading it by construction into the claims which are
allowed.” 311 U.S. at 218; see also id. at 220–21 (“It is a
rule of patent construction consistently observed that a
claim in a patent as allowed must be read and interpreted
with reference to claims that have been cancelled or re-
jected and the claims allowed cannot by construction be
read to cover what was thus eliminated from the patent.”
(citation omitted)). In Schriber-Schroth, the patentee had
cancelled claims reciting a “flexible web” feature and sub-
sequently argued that claims not reciting the feature
should be construed to include it (to escape invalidation by
prior art). Id. at 219–20. The Supreme Court rejected the
patentee’s argument and explained that “the patentee,
having acquiesced in the[] rejection [of claims reciting the
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22 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

We rejected a formalistic approach to the narrowing in-

quiry in Honeywell International Inc. v. Hamilton
Sundstrand Corp., 370 F.3d 1131, 1141–44 (Fed. Cir. 2004)
(en banc). In that case, following the patent office’s rejec-
tion of the original independent claims for obviousness, the
patentee cancelled those independent claims and simply
rewrote two dependent claims into independent form. Id.
at 1141. The rewritten claims were subsequently allowed.
Id. at 1137–38, 1141. Honeywell later asserted infringe-
ment under the doctrine of equivalents of the rewritten
claims. Id. at 1138.
Honeywell argued that rewriting a dependent claim
into independent form does not give rise to the presump-
tion of prosecution history estoppel “because the scope of
the rewritten claims themselves has not been narrowed.”
Id. at 1141. After all, the original dependent claims, by
statutory directive, already contained all the independent
claims’ elements, 35 U.S.C. § 112(d) (“A claim in dependent
form shall be construed to incorporate by reference all the
limitations of the claim to which it refers.”); the rewritten
claims simply made the incorporation express, changing
nothing of substance. But we rejected that argument, rea-
soning that the Supreme Court had already rejected it in
Festo. Id. at 1141–42. In particular, we observed that the
Supreme Court had explained in Festo that this type of ar-
gument “conflates the patentee’s reason for making the
amendment with the impact the amendment has on the
subject matter.” Id. at 1141–42 & n.7 (citing Festo, 535
U.S. at 736–37). “[T]he fact that the scope of the rewritten
claim has remained unchanged will not preclude the appli-
cation of prosecution history estoppel if, by canceling the
original independent claim and rewriting the dependent

flexible web feature], is no longer free to gain the supposed

advantage of the rejected claims by a construction of the
allowed claims as equivalent to them.” Id. at 221–22.
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 23

claims into independent form, the scope of subject matter

claimed in the independent claim has been narrowed to se-
cure the patent.” Id. at 1142.
The focus in Honeywell on the scope of what was aban-
doned, even when a particular claim was not altered in
scope, is reflected in other decisions of this court as well.
See Glaxo Wellcome, Inc. v. Impax Laboratories, Inc., 356
F.3d 1348, 1356 (Fed. Cir. 2004) (“[S]ubject matter surren-
dered via claim amendments during prosecution is also re-
linquished for other claims containing the same limitation.”
(emphasis added)); Deering Precision Instruments, L.L.C.
v. Vector Distribution System, Inc., 347 F.3d 1314, 1325–26
(Fed. Cir. 2003) (applying presumption of prosecution his-
tory estoppel to “all claims containing the [cancelled limi-
tation], regardless of whether the claim was, or was not,
amended during prosecution”). In our non-precedential de-
cision in Mycogen Plant Science, Inc. v. Monsanto Co., we
summarized a key aspect of governing law: “Among the
rules from the original Festo en banc decision that were un-
changed by the Supreme Court and reaffirmed by this
court . . . was our holding that cancellation of claims for
reasons related to patentability in favor of claims with a
narrower literal scope has the same presumptive effect on
claim limitations as amending the claims directly.” 91 F.
Appx. 666, 668 (Fed. Cir. 2004) (non-precedential) (refer-
ring to Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki
Co., 234 F.3d 558 (Fed. Cir. 2000) (en banc), which was va-
cated in Festo, 535 U.S. 722 (2002), which in turn was fol-
lowed by Festo, 344 F.3d 1359 (Fed. Cir. 2003) (en banc))).
When evaluating prosecution history estoppel, we do
not address each claim in isolation, considering only
whether that asserted claim was amended. If that were
the proper approach, this court in Honeywell, for example,
would have rejected the application of prosecution history
estoppel when dependent claims were amended to be put
in independent form, because the scope of those particular
claims did not change by amendment. Instead, this court
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24 COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC

concluded that the cancellation of a prior, broader inde-

pendent claim may give rise to prosecution history estoppel
in relation to a narrower claim, depending on the relation-
ship between the scopes of those claims. Honeywell, 370
F.3d at 1144.
This court in Honeywell also cited favorably to Keith v.
Charles E. Hires Co., 116 F.2d 46 (2d Cir. 1940), in which
the Second Circuit held that prosecution history estoppel
applied where, as with the claims at issue here, the pa-
tentee filed two independent claims and cancelled one after
its rejection. Honeywell, 370 F.3d at 1142 n.8 (discussing
Keith, 116 F.2d at 48). The Second Circuit rejected the
proposition that, for estoppel to apply, the patentee must
have amended the claim that ultimately issued. Keith, 116
F.2d at 47–48. Because the patentee “ha[d] already filed a
claim which contains the necessary differentia” from the
rejected subject matter, maintaining that claim while can-
celling another, broader claim abandoned coverage of “the
element by which that claim differs from the cancelled
claim.” Id. at 48.
For those reasons, we reject Colibri’s contention that
claim 1 itself had to be amended for prosecution history es-
toppel to apply. The close substantive relationship be-
tween the cancelled and retained claims, by Colibri’s own
basic-physics logic for its affirmative assertion of equiva-
lence, is enough to cross the estoppel threshold. A skilled
artisan reading the prosecution history would understand
that some narrowing had occurred through cancelling
claim 39. In that situation, in the absence of further argu-
ments about the scope of narrowing or exceptions to the
presumption of estoppel, the doctrine of equivalents be-
came unavailable to Colibri for the issued claim 1. If
Colibri wished to capture territory involving retraction
that was outside the literal scope of claim 1, it could have
filed a continuation application (and there sought to show
written-description support). Within the confines of the
’294 patent, the public-notice function of prosecution
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COLIBRI HEART VALVE LLC v. MEDTRONIC COREVALVE, LLC 25

history estoppel is served by barring infringement under

the doctrine of equivalents.
IV
Having determined that Medtronic was entitled to
judgment as a matter of law of noninfringement of the ’294
patent, we reverse the district court’s denial of such a judg-
ment. That reversal moots the remaining aspects of Med-
tronic’s appeal (i.e., those relating to invalidity, the
remaining noninfringement arguments, and damages).
The parties shall bear their own costs.
REVERSED