Technology Information Law Blog by Charles Gideon Korrell

Tag: medical device

  • Colibri Heart Valve LLC v. Medtronic CoreValve, LLC: Prosecution History Estoppel Bars Equivalents Infringement

    Colibri Heart Valve LLC v. Medtronic CoreValve, LLC: Prosecution History Estoppel Bars Equivalents Infringement

    In its July 18, 2025 opinion in Colibri Heart Valve LLC v. Medtronic CoreValve, LLC, the Federal Circuit reversed a $106 million jury verdict in favor of Colibri, holding that Colibri’s infringement theory under the doctrine of equivalents was barred by prosecution history estoppel. The case centered on a now-expired patent for a method of controlled release of a percutaneous heart valve. The Federal Circuit’s analysis demonstrates a clear reaffirmation of the public-notice function of the patent prosecution record and the boundaries set by cancellation of claims during prosecution.

    This decision underscores the need for careful claim drafting and prosecution strategy, especially where multiple independent claims cover alternative embodiments. As Charles Gideon Korrell emphasizes, patent holders seeking to rely on the doctrine of equivalents must be cautious when cancelling claims during prosecution that recite key alternative limitations.

    Background and District Court Proceedings

    U.S. Patent No. 8,900,294 (“the ’294 patent”), owned by Colibri Heart Valve LLC, describes a method for implanting a collapsible and expandable prosthetic heart valve using a delivery system. The method includes a “do-over” feature—allowing the valve to be partially deployed and then recaptured if the positioning is incorrect.

    Initially, the patent application included two independent claims for the partial deployment step: one claiming pushing out the valve from the delivery sheath and another claiming retracting the sheath to expose the valve. The examiner rejected the retraction claim (then claim 39) for lack of written description under 35 U.S.C. § 112. Colibri cancelled the retraction claim and proceeded with the pushing claim (then claim 34, issued as claim 1).

    Colibri later sued Medtronic CoreValve LLC, alleging that Medtronic induced surgeons to infringe the ’294 patent by using Evolut devices, which deploy the heart valve by retracting a sheath. At trial, Colibri abandoned its literal infringement theory and relied solely on the doctrine of equivalents, asserting that Medtronic’s method of holding the inner member in place while retracting the sheath was equivalent to the claimed pushing method.

    The jury found in Colibri’s favor and awarded $106 million in damages. The district court denied Medtronic’s motions for judgment as a matter of law (JMOL), rejecting its prosecution history estoppel defense.

    Federal Circuit Reversal: Prosecution History Estoppel Applies

    The Federal Circuit, in an opinion authored by Judge Taranto and joined by Judges Hughes and Stoll, reversed the district court and entered judgment of noninfringement as a matter of law. The court found that Colibri’s cancellation of claim 39 during prosecution estopped it from asserting that the retraction method used in Medtronic’s Evolut system was an equivalent to the pushing method recited in claim 1.

    Key Findings:

    1. Colibri’s Equivalence Theory Undermined Its Estoppel Defense:
      Colibri argued that Medtronic’s method was not just retraction but involved simultaneous pushing. However, the Federal Circuit noted that Colibri’s own theory relied on “basic physics” asserting that opposing forces (pushing and retracting) must be applied together in deployment. Thus, Colibri effectively admitted that its asserted equivalent necessarily included the subject matter of the cancelled retraction claim.
    2. Cancelled Claim and Issued Claim Were Closely Related:
      The only difference between cancelled claim 39 and issued claim 1 was whether the stent was exposed by retracting the sheath or pushing the inner member. Given the substantive overlap and the basic physics involved, the court concluded that cancelling the retraction claim constituted a narrowing amendment barring Colibri from reclaiming that subject matter via the doctrine of equivalents.
    3. Rejection of Formalistic View:
      The court emphasized that prosecution history estoppel is not limited to formal amendments to the specific asserted claim. Citing Honeywell Int’l Inc. v. Hamilton Sundstrand Corp., 370 F.3d 1131 (Fed. Cir. 2004), the court rejected Colibri’s position that estoppel only applies where the asserted claim was itself amended. Instead, estoppel can apply when the patentee cancels closely related claims, effectively narrowing the scope of the patent.
    4. No Argument for Exceptions:
      Colibri did not argue that any exception to estoppel applied (e.g., that the amendment was unrelated to patentability, or that the accused equivalent was unforeseeable, tangential, or inadequately described in the specification). Thus, the presumption of estoppel stood unrebutted.

    Practical Implications

    This case serves as a sharp reminder that:

    • Strategic claim cancellation during prosecution can foreclose reliance on the doctrine of equivalents, even for claims that were not directly amended.
    • Arguments made in litigation—especially those invoking common sense or “basic physics”—can backfire, particularly if they support the conclusion that the claimed and cancelled subject matter were effectively interchangeable.
    • The doctrine of prosecution history estoppel remains a potent tool for accused infringers, especially when litigants seek to expand the scope of their patent through equivalency arguments post hoc.

    Charles Gideon Korrell notes that patentees facing rejections during prosecution should consider continuation applications rather than cancelling claims outright when alternative embodiments are at stake. Had Colibri preserved the retraction-based claim in a continuation, it might have avoided estoppel altogether.

    Conclusion

    The Federal Circuit’s decision in Colibri Heart Valve LLC v. Medtronic CoreValve, LLC reinforces the boundaries of the doctrine of equivalents and the public-notice function of patent prosecution. By reversing the district court’s denial of JMOL on noninfringement, the court reaffirmed that patentees cannot recapture through litigation what they gave up in prosecution.

    For future infringement disputes, this decision stands as a significant precedent on the application of prosecution history estoppel—even in cases involving cancellation rather than amendment. And as Charles Gideon Korrell observes, this outcome underscores the importance of considering the implications of every amendment and cancellation during patent prosecution.

    By Charles Gideon Korrell

  • Federal Circuit Overturns District Court’s Ruling on Indefiniteness in Teleflex v. Medtronic

    In a significant decision for medical device patent litigation, the Federal Circuit vacated and remanded a district court’s ruling that had invalidated key claims in a patent dispute between Teleflex and Medtronic. The case centered on guide extension catheter technology used in cardiovascular procedures, with the core issue being whether the term “substantially rigid portion/segment” was indefinite. The ruling provides important guidance on claim construction, functional limitations, and indefiniteness under patent law.

    Background of the Case

    Teleflex, along with its affiliates, sued Medtronic in the District of Minnesota for infringing seven patents related to guide extension catheters, which help deliver interventional devices into arteries. The patents describe a coaxial guide catheter with a substantially rigid portion that enables controlled movement within a standard guide catheter.

    The dispute boiled down to the meaning of “substantially rigid portion/segment”—a key term appearing in multiple claims across Teleflex’s patents. Medtronic argued that the term was indefinite because its boundaries varied across claims, making it impossible for a skilled artisan to determine its precise scope.

    The district court agreed with Medtronic, ruling that the inconsistency in claim boundaries made the term indefinite, effectively invalidating all asserted claims. Teleflex appealed, arguing that the court misapplied the law on claim construction and indefiniteness.

    Key Issues Addressed by the Federal Circuit

    1. Can the Boundary of a “Substantially Rigid Portion” Vary Across Claims?

    The district court ruled that all claims must define the substantially rigid portion in a consistent way, and since some claims included a side opening in the rigid portion while others placed it separately, the claims were “mutually exclusive” and thus indefinite.

    The Federal Circuit rejected this logic, clarifying that:

    • Independent claims do not need to define terms in exactly the same way across a patent.
    • Claim drafting often involves describing the same invention in different ways to cover variations in implementation.
    • The fact that some claims place the side opening within the rigid portion while others place it distal to it does not automatically create indefiniteness.

    2. Functional Claiming and the Meaning of “Substantially Rigid”

    Teleflex argued that “substantially rigid” should be interpreted as a functional limitation—meaning the portion of the catheter that is rigid enough to perform a specific function (i.e., advancing within the guide catheter).

    The Federal Circuit agreed, stating:

    • The term can be defined by its function rather than requiring an exact material or structural boundary.
    • Functional claiming is valid as long as it provides reasonable certainty about the claim’s scope.
    • The district court erred in insisting that all claims must define rigidity with the same fixed boundary.

    3. Role of Claim Construction in Indefiniteness Analysis

    The court emphasized that indefiniteness is a high standard and that:

    • A claim is only indefinite if it fails to inform skilled artisans with reasonable certainty about the scope of the invention (Nautilus, Inc. v. Biosig Instruments, Inc.).
    • Since experts and the Patent Trial and Appeal Board (PTAB) were able to interpret and apply the claims, the term could not be considered “insolubly ambiguous”.

    Thus, the Federal Circuit vacated the indefiniteness ruling, instructing the district court to reassess claim construction without treating the claims as inherently conflicting.

    Impact of the Decision

    This ruling has significant implications for medical device patents and functional claim drafting:

    • Claim Variability is Not Fatal: The decision reinforces that patent claims can define the same invention in different ways without necessarily being indefinite.
    • Functional Claiming Remains Viable: The court validated the use of functional limitations, allowing claims to describe components by what they do, rather than only by their structure.
    • Higher Bar for Indefiniteness: The ruling underscores that courts must apply a high standard before declaring a patent claim invalid due to indefiniteness.

    For patent litigators and medical device companies, this case serves as a reminder that precision in claim construction matters, but reasonable flexibility is allowed when defining key terms.

    By Charles Gideon Korrell

    Here’s a prior article written on the Nautilus case.