CAFC Finds IPR Petitioner Did Not Rely on AAPA as Basis for Obviousness Grounds in Affirming PTAB Invalidation

On Monday, the U.S. Court of Appeals for the Federal Circuit issued a precedential decision in Shockwave Medical, Inc. v. Cardiovascular Systems, Inc. dismissing cardiovascular health company Shockwave Medical’s appeal arguing that the Patent Trial and Appeal Board (PTAB) erroneously relied on applicant admitted prior art (AAPA) in finding its patent claims obvious. The Federal Circuit found the PTAB’s ruling consistent with its own case law on AAPA, which provided general background knowledge for a person of ordinary skill in the art without serving as the sole basis for the PTAB’s obviousness finding.

In inter partes review (IPR) proceedings petitioned by Cardiovascular Systems (CSI), the PTAB invalidated all but claim 5 from Shockwave’s U.S. Patent No. 8956371, Shockwave Balloon Catheter System. The angioplasty catheter and system for breaking obstructions in bodily structures claimed by the ‘371 patent applies lithotripsy, a well-known technique using high-intensity sonic waves to break up kidney stones, to plaque deposits calcified in human patients as an angioplasty treatment. Along with a typical over-the-wire angioplasty and balloon catheter, the claimed device of the ‘371 patent includes electrodes to generate shockwaves in fluid-filled balloons attached to the pulse generator.

Whether AAPA is Basis for Grounds of Invalidity Depends on How IPR Petition is Fashioned

The Board agreed with CSI’s arguments that the challenged claims of the ‘371 patent were obvious in light of a European patent application (“Levy”) describing the use of laser-generated pulses to disintegrate plaque in blood vessels. CSI had contended that it would have been obvious to one of ordinary skill to modify Levy with the well-known angioplasty balloon catheter disclosed in AAPA submitted during prosecution of the ‘371 patent at the U.S. Patent and Trademark Office. The sole surviving claim of the ‘371 patent was claim 5, depending from claim 2’s angioplasty catheter with metallic electrodes and having the additional limitation that the electrodes are disposed adjacent to and outside of the guide wire lumen.

Tracing its case law on AAPA as outlined in recent decisions in patent appeals between Qualcomm and Apple from 2022 (Qualcomm I) and 2025 (Qualcomm II), the Federal Circuit reiterated that AAPA as evidence of general background knowledge of an ordinarily skilled artisan is appropriate if other patents or printed publications form the basis for the grounds of invalidity. In Qualcomm I, the Federal Circuit held that AAPA cannot be the basis for an invalidity ground in an IPR petition, a conclusion it reiterated in Qualcomm II when the appellate court found that the PTAB erred by expressly labeling the AAPA as part of its basis for the obviousness ground.

In contrast to Qualcomm II, the Federal Circuit found here that CSI only used Shockwave’s AAPA to show what the ‘371 patent itself acknowledged: that the claimed over-the-wire angioplasty balloon catheter was well-known, satisfying those express claim limitations. Shockwave contended that, because the PTAB listed its AAPA in a table under the title “Reference(s)/Basis,” the AAPA was clearly labelled as a basis for a ground of invalidity. However, for the purposes of 35 U.S.C. § 311(b)’s limitation on grounds for invalidity in IPR proceedings “on the basis of prior art consisting of patents or printed publications,” “what matters… is the grounds raised in the petition, and CSI’s petition never phrased the AAPA in terms of constituting a basis for its obviousness arguments.”

CAFC Reverses No Invalidity of Claim 5 for Failure to Consider Prior Art Holistically

Several other arguments advanced by Shockwave were similarly dismissed by the Federal Circuit. While Shockwave argued a narrower construction of “angioplasty balloon” limiting the definition to balloons displacing plaque into vessel walls, the appellate court noted that the ‘371 patent’s specification expressly disavowed any requirement that the balloon must exert pressure on artery walls to break plaque. The Federal Circuit also found that the Board properly outlined reasons for an ordinarily skilled artisan to combine Levy with the AAPA’s angioplasty catheter, including increasing the treatments Levy could perform, and that Levy’s specification disclosed the use of shockwaves in blood vessels and was not limited to cleaning tooth canals. As to secondary considerations, the Federal Circuit found that a declaration from Shockwave’s expert that “the Shockwave [intravascular lithotripsy] devices include each feature recited in the claims” did not sufficiently link the structure of Shockwave’s product to the claims of the ‘371 patent.

Moving on to CSI’s cross-appeal, the Federal Circuit found that CSI had Article III standing based on public statements made by Shockwave’s President that claim 5, which survived IPR proceedings, would be asserted against competitors in the intravascular lithotripsy (IVL) market. The Federal Circuit noted that, at the time of CSI’s cross-appeal, the company was close to initiating clinical trials of an IVL product reaching the design freeze phase.

Having found standing, the Federal Circuit left undisturbed the PTAB’s finding that a Japanese patent application (“Uchiyama”) did not meet claim 5’s limitation as to the positioning of the claimed electrodes. However, the appellate court faulted the PTAB for considering Uchiyama alone and not combined with the teachings of Levy and AAPA, which led the Board to improperly discount CSI’s argument that placing Uchiyama’s electrodes outside of the lumen would have been a routine design choice. Shockwave’s only argument in favor of claim 5’s validity, that placing electrodes too close to tissue would cause tissue damage, was elsewhere rejected by the PTAB, making reversal instead of vacatur appropriate.