In a precedential decision, the U.S. Court of Appeals for the Federal Circuit recently breathed new life into a set of medical device patents previously deemed invalid. The case, Vascular Solutions LLC v. Medtronic, Inc., centers on guide extension catheters—slender tubes used in heart procedures to help deliver stents and other devices to hard-to-reach areas of coronary arteries.
At the heart of the dispute was the interpretation of a particular phrase used in the patents at issue: “substantially rigid portion.” What began as a technical disagreement over the rigidity of catheter segments broadened into a dispute about how patent claims should be construed and whether different claims within the same patent family can describe the same invention in varying ways. The Federal Circuit’s ruling, issued on September 16, 2024, not only revives the patents in question but also provides crucial guidance on patent claim interpretation.
Procedural History
In this case, Vascular Solutions, along with related Teleflex companies (collectively with Vascular Solutions, “Teleflex”), initially sued Medtronic for patent infringement in the U.S. District Court for the District of Minnesota. The dispute focused on Medtronic’s guide-extension-catheter product, Telescope, which Teleflex claimed infringed several of its patents.
The case took a complex path through the legal system. After the initial filing, Medtronic challenged the patents at the Patent Trial and Appeal Board (PTAB). The PTAB instituted 15 inter partes reviews (IPRs) but ultimately found that Medtronic had failed to prove unpatentability for all the asserted claims. Following these IPR decisions, the case returned to the district court.
As the case progressed, the district court rejected Teleflex’s second preliminary injunction request and questioned Teleflex’s claim construction. The court grouped the claims into two categories:
- Group One: Claims that described the side opening as part of the substantially rigid portion.
- Group Two: Claims that described the side opening as separate from and distal to the substantially rigid portion.
In denying Teleflex’s request for preliminary injunction, the district court questioned “the soundness of construing the claims in a way that would allow Teleflex to successfully assert Group One and Group Two claims against the same accused product.”
The district court then proceeded to claim construction. After rejecting both parties’ constructions, the court appointed former USPTO Director Andrei Iancu as an independent expert to analyze the issue. Iancu rejected both proposed constructions of the term “substantially rigid portion/segment” in the claims. Teleflex had urged Iancu to adopt a construction that would split the claims into two groups: one where the side opening is included in the substantially rigid portion, and another where it is not. Medtronic, on the other hand, urged Iancu to find the claims indefinite. Iancu did not find the claims to be indefinite. However, he also “shared the [district court’s] skepticism at Teleflex’s efforts to secure a construction that would allow it to map ‘two mutually exclusive limitations’ onto the same accused product,”
The district court ultimately agreed with Medtronic and concluded that the patent claims were indefinite—that is, too vague for a person skilled in the field to understand their scope with reasonable certainty. The decision hinged on the district court’s view that different claims within the same patent family appeared to be “mutually exclusive” in how they described the rigid portion of the catheter. Since all asserted claims included the term “substantially rigid portion/segment,” the parties stipulated to final judgment.
Teleflex appealed the decision to the U.S. Court of Appeals for the Federal Circuit.
Key Issues and the Federal Circuit’s Analysis
The Federal Circuit’s review centered on two critical issues with important implications:
1. The concept of “mutual exclusivity” in patent claims: The Federal Circuit held that the district court erred when it determined the asserted claims were “mutually exclusive” and indefinite. The Federal Circuit rejected the notion that claims in a patent cannot vary in how they describe the disclosed subject matter or that independent claims must be totally consistent with other independent claims.
The Federal Circuit stated: “The district court’s conclusion, in effect, means that (1) claims in a patent cannot vary in the way they claim the disclosed subject matter, and (2) independent claims must be totally consistent with other independent claims. Claiming is not restricted in this way.” It emphasized that the art of patent claiming often involves drafting claims in various ways to encompass different aspects of the disclosed subject matter, as long as each claim informs those skilled in the art about the scope of the invention with reasonable certainty.
The Federal Circuit instructed the district court to “conduct claim construction on a claim-by-claim basis with the understanding that, at the claim construction stage, the claims are not necessarily ‘mutually exclusive’ since each independent claim is a different ordered combination of limitations.”
- Interpretation of “substantially rigid portion/segment”: The Federal Circuit held that the boundary of the “substantially rigid portion/segment” does not have to be consistent across claims. In doing so, it adopted a functional approach to interpreting this term, explaining that it is a functional limitation defined by its ability to perform a certain function.
The Federal Circuit explained: “The ‘substantially rigid portion/segment’ limitation is a functional limitation, meaning the substantially rigid portion is a portion of the catheter that is substantially rigid enough to achieve some function.” This functional interpretation allows for flexibility in how the term is applied across different claims.
While explaining that claim terms should generally be construed consistently across related patents, the Federal Circuit clarified that this doesn’t mean the physical boundaries of a component must be identical in every claim: “This decision clarifies that the term ‘substantially rigid portion’ be construed the same way across the patents, but that construction can be a functional construction that does not specify the boundary of the ‘substantially rigid portion.'”
Finally, the Federal Circuit rejected Medtronic’s argument that this interpretation might confuse a person skilled in the field, noting that the claims themselves indicate how to measure the boundary on a claim-by-claim basis, and also found Medtronic’s concerns about infringement premature at the claim construction stage.
The Federal Circuit vacated the district court’s judgment and remanded the case for further proceedings.
Conclusion
The Federal Circuit’s analysis reflects a nuanced, less restrictive approach to claim construction. By focusing on the functional aspects of claim limitations and allowing for flexibility in how inventions are described across multiple claims, the court’s reasoning provides a framework for interpreting claims that balances the need for clarity with the need for flexibility during the patent drafting stage.
