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Disclaimer in Specification Restricts Claim Scope

March 14, 2001
Burns, Robert

Decision icon Decision

Last Month at the Federal Circuit - April 2001

Judges: Bryson (author), Plager, and Dyk (concurring)

In SciMed Life Systems, Inc. v. Advanced Cardiovascular Systems, Inc., No. 99-1499 (Fed. Cir. Mar. 14, 2001), the Federal Circuit affirmed a district court’s claim construction and grant of SJ of noninfringement based on disclosure in the specifications of the patents at issue disclaiming embodiments like those now accused of infringing.

SciMed Life Systems, Inc. (“SciMed”) owns three U.S. patents drawn to features of balloon dilatation catheters. SciMed filed suit against Advanced Cardiovascular Systems, Inc. (“ACS”) in the United States District Court for the Northern District of California, charging ACS with infringing each of the three patents. On ACS’s motion for SJ, the district court ruled that ACS had not infringed the disputed patents.

SciMed argued on appeal that the district court had improperly read an element (coaxial lumens) from the written description into the claims, where the claims themselves contained no such limitation. The Federal Circuit disagreed. The Court found that at various points in the common specification(including in the abstracts) of the three patents, the disclosed invention uses coaxial rather than side-byside lumens, i.e., the guide wire lumen is contained within the inflation lumen and the inflation lumen is annular. According to the Court, when read together, the common portions of the specification lead to the inescapable conclusion that the references in the asserted claims to an inflation lumen “separate from” the guide wire lumen must be understood as referring to coaxial lumens and, thus, that the asserted claims read only on catheters having coaxial lumens.

The Court explained that one purpose for examining the specification is to determine if the patentee has limited the scope of the claims. Where the specification makes clear that the invention does not include a particular feature, that feature is deemed to be outside the reach of the claims of the
patent, even though the language of the claims, read without reference to the specification, might be considered broad enough to encompass the feature in question. Moreover, when the preferred embodiment is described as the invention itself, the patent claims are not entitled to a broader scope than that embodiment. Because ACS’s device utilized a dual-lumen configuration, the Court affirmed SJ of no literal infringement.

The Federal Circuit also agreed that infringement could not exist under the DOE because the common specification criticized and distinguished prior art catheters using dual-lumen configurations. Accordingly, SciMed was prohibited from invoking the DOE to embrace a structure that was excluded from the claims.

In a concurring opinion, Judge Dyk explained that while he agreed with the result reached by the majority, he cautioned that the decisions of the Federal Circuit failed to provide adequate guidance as to when it is appropriate to look to the specification to narrow the claim by interpretation and when it is not appropriate to do so.