In Trivascular, Inc., v. Samuels, [2015-1631) (February 5, 2015), the Federal Circuit affirmed a rare PTAB determination in an IPR that the claims of U.S. Patent No. 6,007,575 were not shown to be invalid. The claims were directed to stents with an inflatable cuff for securing the stent in a blood vessel.

TriVascular argued that the Board erred in construing “circumferential ridges” to mean a “raised strip disposed circumferentially about the outer surface of the inflatable cuff,” contending that it should have been construed to mean “an elevated part of the outer surface disposed about the inflatable cuff that can be either continuous or discontinuous.”  The Federal Circuit found that TriVascular’s proposed interpretation was unreasonably broad, and that find 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 further argued that the Board should have applied prosecution history disclaimer, and found that Samuels had disclaimed the narrower construction that the ridges must be continuous.  The Federal Circuit said that the same general tenets that apply to prosecution history estoppel apply to prosecution history disclaimer.  Both doctrines require that the claims of a patent be interpreted in light of the proceedings in the PTO during the application process.  As applied to a disclaimer analysis, “the prosecution history can often inform the meaning of the claim language by demonstrating how the inventor understood the invention.”   Disclaimer “ensures that claims are interpreted by reference to those that have been cancelled or rejected, but the party seeking to invoke prosecution history disclaimer bears the burden of proving the existence of a “clear and unmistakable” disclaimer that would have been evident to one skilled in the art.

TriVascular argued that the disclaimer arose when Samuels amended the claims to recite “continuously circumferential ridges,” but the claims that were later allowed did not have this requirement, but instead had other limitations defining over the prior art.  However the Federal Circuit did not find this sufficient to work a clear and unmistakable disclaimer.

Regarding obviousness, the Federal Circuit noted that Although the KSR test is flexible, the Board must still be careful not to allow hindsight reconstruction of references without any explanation as to how or why the references would be combined to produce the claimed invention.  The Federal Circuit found that the Board’s findings that a skilled artisan would neither have had the motivation to combine nor a reasonable likelihood of success in combining the references were supported by substantial evidence, and supported the Board’s conclusion on nonobviousness.

Finally the Federal Circuit rejected Trivascular’s complaint that the final written decision was inconsistent with the Board’s institution decision.  The Federal Circuit commented that this misguided theme pervaded TriVascular’s briefs, and said that contrary to TriVascular’s assertions:

 the Board is not bound by any findings made in its Institution Decision. At that point, the Board is considering the matter preliminarily without the benefit of a full record. The Board is free to change its view of the merits after further development of the record, and should do so if convinced its initial inclinations were wrong. To conclude otherwise would collapse these two very different analyses into one, which we decline to do.

The Federal Circuit added that TriVascular’s argument also fails to appreciate that there is a significant difference between a petitioner’s burden to establish a “reasonable likelihood of success” at institution, and actually proving invalidity by a preponderance of the evidence at trial.