A Patent Survives an IPR

Stephen G. Adrian | February 10, 2016

Trivascular, Inc. v. Shaun L. W. Samuels

February 5, 2016

Before: Moore, O’Malley, and Wallach.  Opinion by O’Malley


This decision provides a good summary of issues which a patent practitioner may face when prosecuting a patent application or an inter partes review (IPR). In particular, the decision provides insight on claim construction from the viewpoints of “broadest reasonable interpretation” and prosecution history disclaimer. Furthermore, the decision provides insight on making an obviousness analysis when arguing that a reference teaches away or that a combination of references would destroy the objective of the reference.


In 2013, Dr. Samuels sued TriVascular alleging infringement of U.S. patent No. 6,007,575 (the ’575 patent). TriVascular subsequently filed a petition for inter partes review (“IPR”) on August 5, 2013. The Board instituted review on February 4, 2014, based on two obviousness grounds over (1) Samuels ‘851 and Todd, and (2) Lazarus and Todd. In the Institution Decision, the Board construed the phrase “circumferential ridge disposed about the inflatable cuff” to mean “raised strip disposed circumferentially about the outer surface of the inflatable cuff.” Although Samuels had presented arguments in response to the petition that the Samuels reference teaches away and that the combination of references would destroy the objective of the reference, the Board found that TriVascular had established a reasonable likelihood of success based “on the present record.”

The IPR continued whereby each side introduced respective expert reports. The Board issued a final decision on December 13, 2014, holding that TriVascular failed to meet its burden of establishing that the challenged claims were unpatentable.


Claim 1 of the ‘575 patent recites:

1.  An inflatable intraluminal stent adapted to be secured to the interior of a tubular structure within the human body comprising:

a)  an inflatable and deflatable cuff of generally hollow cylindrical continuation having a collapsible lumen, an inner surface, an inlet, an outlet and a friction enhancing outer surface, said friction-enhancing outer surface featuring inflatable protrusion(s) including at least one circumferential ridge disposed about the inflatable cuff, said friction-enhancing outer surface engaging the interior of the tubular structure without penetration to prevent the cuff from moving in a longitudinal direction with respect to the tubular structure when said cuff is in a fully inflated condition;

b) means for injecting an inflation material into said cuff to inflate it; and

c) a valve integral with the inflatable cuff for permitting entry of the inflation material from the means for injecting and thereafter sealing said cuff to prevent deflation.

The ‘575 patent provides a stent having an inflatable and deflatable cuff 17 which can be inflated by introducing fluid into each of the circumferential ridges 25 illustrated below:






The prior art of Samuels ‘851 taught use of inflatable protrusions containing penetrating spikes capable of securing the stent within the vessel wall:





Todd taught use of non-penetrating “gripping protuberances” which are solid as opposed to hollow inflatable ridges:








Claim Construction

TriVascular argued that the Board erred in its claim construction by requiring “circumferential ridges” to mean a “raised strip disposed circumferentially about the outer surface of the inflatable cuff” but instead should have construed the term to include either continuous or discontinuous elevated parts (so as to read on Samuels ‘851). TriVascular argued that the Board’s construction would be inconsistent with the plain meaning of the term, and that prosecution history disclaimer should bar Samuels from arguing a narrower construction. TriVascular asserted that the construction is unreasonably narrow because discontinuous protrusions would collectively form a mountain ridge similar to the Blue Ridge Mountains.

The Board, however, determined that the plain meaning of “circumferential ridges” under the broadest reasonable interpretation would not encompass discontinuous points arranged in a circular pattern on the surface of a stent. The CAFC found that the Board’s reliance on the dictionary definition of ridge when considered in the context of the written description and plain language of the claims was proper. TriVascular failed to explain why a topological definition would encompass discontinuous peaks when mountain ranges typically consist of adjacent, continuous mountain peaks. Therefore, such a definition would be unreasonably broad.

TriVascular also asserted that prosecution history disclaimer should prohibit a construction that “circumferential ridges” is limited to continuous ridges. TriVascular pointed out that (1) the examiner initially rejected the claims by interpreting Samuels ‘851 as having inflatable protrusions that form a circumferential ridge, (2) Samuels responded that Samuels ‘851 did not disclose continuous circumferential ridges and introduced an amendment adding the word “continuously” and (3) the finally issued claims did not contain “continuously.” The CAFC agreed with the Board’s finding that TriVascular focused on the amendment in isolation and that the positions of the Examiner and patent applicant had changed such that patentability relied on other amendments instead of “continuously.” That is, the Examiner never adopted Samuel’s proposed amendment as a reason for allowing the claims over the prior art.


A key distinction between the ‘575 patent and the prior art resides in use of inflatable, circumferential ridges that do not penetrate the vessel wall. TriVascular had argued that a skilled artisan would have been motivated to combine Samuels and Todd by replacing the barbs of Samuels with the gripping protuberances of Todd to obtain the desirable result of non-penetrating stent fixation. Such a modification, however, would destroy the basic objective of the barbs to penetrate surrounding tissue. Furthermore, not only the barbs would need to be replaced, but also the underlying recesses in Samuels ‘851 would need to be replaced. Still further, it would not have been obvious to substitute inflatable barbed recesses with non-penetrating protuberances because the protuberances of Todd are not inflatable.

Lastly, TriVascular contended that the Board’s ultimate conclusion of nonobviousness is inconsistent with its findings in the Institution Decision. This argument fails for a number of reasons, including (1) the Board is not bound by any findings in its Institution Decision as the Board is considering the matter preliminarily without the benefit of a full record; (2) there is a significant difference between a petitioner’s burden to establish a reasonable likelihood of success at institution and actually proving invalidity by the preponderance of the evidence at trial; and (3) although a skilled artisan may have had a reasonable expectation of success in replacing the entire recesses of Samuels with the protuberances of Todd, there was insufficient motivation to substitute just the barbs of Samuels ‘851 with the protuberances of Todd. Samuels ‘851 taught away from substituting only the barbs as the barbs were the primary objective of anchoring, and replacing just the barbs of Samuels ‘851 would not have satisfied the “circumferential ridge” limitation since barbs were individual, discontinuous points.


1.  Expert reports are critical in an IPR. Patent practitioners may want to consider use of similar declarations during ex parte prosecution.

2.  Define what is meant by terms in your specification, particularly if the terms are not to be given their ordinary meaning.

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