This case addresses whether the district court correctly applied prosecution disclaimer to (i) import a negative limitation into a child patent claim based on prosecution of a related parent patent with materially different claim language, and (ii) read a further negative limitation about a guide wire’s path into two claims based largely on examiner statements and applicant conduct in an ancestor patent’s prosecution and later IPR-related briefing.
Background
Maquet Cardiovascular LLC owns U.S. Patent No. 10,238,783 (the “’783 patent”), which relates to intravascular blood pump systems used to deploy a pump to a desired location in a patient’s circulatory system. The patent describes difficulties with prior-art systems that required separate “supplemental guiding mechanisms” (e.g., large guide catheters) that could be hard to maneuver in patients. To address this problem, the ’783 patent focuses on integrated guide mechanisms on the pump system itself, including examples described as “over-the-wire” configurations with a central lumen, “side-rigger/rapid exchange” configurations with a side lumen, and a guide-catheter-type conduit assembly.
Maquet sued Abiomed in the District of Massachusetts asserting infringement of claims of U.S. Patent No. 9,789,238 (the ’238 patent) and later added claims of the ’783 patent (a divisional of the ’238 patent).
The primary issues on appeal centered on the proper claim construction of certain limitations in claim 1 and claim 24 of the ’783 patent. Claim 1 recites a “guide mechanism comprising a lumen” and further recites that the guide mechanism is configured to allow a guide wire to “slideably advance therealong.” Claim 24 recites (among other limitations) that “the guide wire does not pass through the rotor hub or the catheter.”
In 2022, the district court’s claim construction order adopted constructions that based substantially on Abiomed’s prosecution disclaimer theories. The district court accepted Abiomed’s argument that prosecution of certain claims in the ’238 patent warranted importing an additional negative limitation that the guidewire lumen is “not distal to the cannula” in claim 1. The district court also accepted Abiomed’s argument that prosecution history from an ancestor patent supported narrowing both claim 1 and claim 24 by including a limitation that the guide wire does not extend through the free space between rotor blades, relying heavily on the examiner’s reasoning in a notice of allowance distinguishing prior art and the court’s view that Maquet had “adopted” that position.
After those constructions, the parties stipulated to non-infringement under the district court’s constructions, and final judgment entered. This appeal followed.
Issue(s)
The appeal presented three principal questions:
- Whether the district court erred by importing into ’783 claim 1 a negative limitation that the guidewire lumen “is not distal to the cannula” based on prosecution of different claims in the parent ’238 patent.
- Whether the district court properly applied prosecution disclaimer to construe claim 1 as requiring that the guide wire does not extend through the free space between rotor blades.
- Whether the district court properly applied prosecution disclaimer to construe claim 24 as also requiring that the guide wire does not pass through the free space between rotor blades (in addition to the claim’s express “rotor hub or catheter” language).
Holding(s)
The Federal Circuit held the district court erred in importing the “not distal to the cannula” negative limitation into claim 1, because the relied-upon ’238 prosecution involved materially different claim language and limitations and therefore did not support disclaimer for the ’783 claim term at issue.
The Federal Circuit further held the district court erred in construing claim 1 to require that the guide wire does not run through the free space between rotor blades, because the record did not show a clear and unmistakable disavowal.
The Federal Circuit further held the district court erred in importing the same “rotor-blade free space” limitation into claim 24, because the ancestor prosecution did not address a sufficiently common limitation and, in any event, did not reflect a clear and unmistakable disavowal.
The Court vacated and remanded the non-infringement judgment as to the ’783 patent and left undisturbed the judgment as to the ’238 patent.
Reasoning
The Federal Circuit reiterated that related-patent prosecution history can be relevant where it addresses a limitation in common with the patent-in-suit, but rejected the argument that “common subject matter” alone is enough. Here, the district court erroneously relied on a prosecution history that involved then-pending ’238 claims directed to an “entire elongate lumen” positioned “distal to” particular components. The Federal Circuit found that these limitations differed meaningfully from the ’783 claim 1 language “guide mechanism comprising a lumen,” and therefore did not impose the same positional/extent requirements. Because the limitations were not sufficiently similar, the Court held it was error to import the negative limitation “not distal to the cannula” into ’783 claim 1.
As to the “guide wire” term in claim 1, the Federal Circuit agreed the ancestor prosecution history was relevant because the guide-wire limitation was essentially identical. But relevance alone did not establish disclaimer. The Court emphasized that a prosecution disclaimer has a high bar: disclaimer requires a disavowal that is clear and unmistakable. The district court found disclaimer based on the examiner’s allowance discussion distinguishing prior art (which threaded a guide wire through rotor blades and lacked a separate guide lumen) and the view that Maquet “adopted” the examiner’s position. The Federal Circuit disagreed, explaining that an applicant’s silence in response to an examiner’s notice of allowance generally does not rise to a clear and unmistakable disavowal. The Court also rejected Abiomed’s attempt to rely on later IPR-related statements, finding them too generalized and not a clear surrender of the disputed guide-wire path.
The Court additionally rejected the argument that excluding a lumen from the rotor-blade free space necessarily excludes the guide wire itself, noting the specification’s disclosure consistent with a removable guide wire (which could pass through an area during placement and then be removed before pump operation).
Finally, the Federal Circuit concluded that the ancestor prosecution history could not be used to import the “rotor-blade free space” limitation into ’783 claim 24 because the limitations were not sufficiently aligned. Claim 24 does not recite the same guide mechanism/lumen configuration and includes an express restriction that the guide wire does not pass through the rotor hub—a limitation not at issue in the ancestor claim or its prosecution. Lacking a sufficiently common limitation to anchor disclaimer, the district court’s construction could not stand, and the Federal Circuit reiterated that the record lacked a clear and unmistakable disavowal.
This case is a useful reminder that prosecution disclaimer remains a narrow doctrine: courts should not import negative limitations across related patents absent close alignment in the claim language, and alleged surrender must be clear and unmistakable—not inferred from examiner commentary or applicant silence. The decision also highlights the importance, for both litigants and prosecutors, of tying any disclaimer arguments to the specific claim limitations at issue, rather than broader “family” narratives.