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.
      

 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 

(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 

, 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; 

 col. 2, lines 52–54. Blood
 flows through valves in the heart from areas of relatively
 high pressure to areas of relatively low pressure. 

 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. 

 col. 1, lines 48–56; 

 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), 

 col. 5, lines 1–7; 

 col. 6, lines 62–64, shown in figures 1
 and 5.




 The leaflets (220) are formed from “a single, continuous,
 uncut layer” of material. 

 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. 

 col. 6, lines 57–67;
 

 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. 

 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. 

 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.
 

 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). 

 col. 11, lines
 48–51; 

 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. 

 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. 

 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). 

 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.” 

 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.
 

 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 

(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, 

, 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.” 

 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 

. 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.” 

. 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.” 

. The district court adopted the recom-
 mended claim construction. Order at 1, Colibri Heart
 Valve LLC v. Medtronic CoreValve LLC, No. 20-cv-00847,
 

, 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.” 

 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 

(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, 

 at
 41–53; (3) the denial of JMOL of no active inducement, 

 at 53–58; and (4) the denial of Medtronic’s motion for a new
 trial on damages, 

 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., 

 (Fed. Cir. 2019) (citing Wechsler v. Macke International
 Trade, Inc., 

 (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., 

 (Fed. Cir.
 2017) (quoting Harper v. City of Los Angeles, 

 (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., 

, 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, 

 (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 

 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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                              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, 

. 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., 

 (2002) (quoting Schriber-
 Schroth Co. v. Cleveland Trust Co., 

, 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, 

 (“Estoppel arises when an amend-
 ment is made to secure the patent and the amendment nar-
 rows the patent’s scope.” (emphasis added)); 

 (“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.” 

; see also 

 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). 

 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., 

, 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, 

(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. 

 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.” 

 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.” 

 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.” 

.
      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., 

 (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., 

, 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.” 

 (Fed. Cir. 2004) (non-precedential) (refer-
 ring to Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki
 Co., 

 (Fed. Cir. 2000) (en banc), which was va-
 cated in Festo, 

 (2002), which in turn was fol-
 lowed by Festo, 

 (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., 

 (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, 

). 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.” 

.
      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