July 30, 2025

In Shockwave Medical, Inc. v. Cardiovascular Systems, Inc., Appeal Nos.  2023-1864, 2023-1940, ---F.4th---, 2025 WL 1922023 (Fed. Cir. July 14, 2025), we see the Court building on prior decisions like Qualcomm Inc. v. Apple Inc., 24 F.4th 1367 (Fed. Cir. 2022) (“Qualcomm I”), and Qualcomm Inc. v. Apple Inc., 134 F.4th 1355 (Fed. Cir. 2025) (“Qualcomm II”), to provide further guideposts on use of AAPA in IPRs. 

The challenged patent is directed to a method for treating atherosclerosis through electrohydraulic lithotripsy. 2025 WL 1922023, at *1-2.  The claimed device uses a typical over-the-wire angioplasty balloon catheter and adds electrodes and a pulse generator. Id.  The primary reference Cardiovascular Systems (“CSI”) relied on is a published European application (“Levy”) that describes using laser-generated pulses to disintegrate plaque in blood vessels. Id. at *2.  CSI also cited the challenged patent’s disclosure of typical prior art over-the-wire angioplasty balloon catheters “[that] are usually noncompliant with a fixed maximum dimension when expanded with a fluid such as saline.” Id.  CSI argued it would have been obvious to modify Levy with the well-known angioplasty balloon catheter disclosed by AAPA. Id.  The PTAB initially said the AAPA qualified as prior art consisting of patents or printed applications and found all claims but one unpatentable for obviousness. Id.  The PTO issued binding guidance shortly thereafter that AAPA is not prior art consisting of patents or printed publications under § 311(b) and the PTAB initiated a rehearing to allow the panel to consider and follow this guidance. Id.  The PTAB issued a final decision on rehearing in which it relied on AAPA only as evidence of the background knowledge in the art as to typical over-the-wire balloon catheters and again found all claims but one were shown to be obvious. Id.  Shockwave appealed and CSI cross appealed. Id. at *2-3.  The prior art combinations at issue involved “Levy as modified by AAPA” in combination with other prior art references. Id.

Responding to Shockwave’s claim that the petition and PTAB improperly relied on AAPA, the Court noted that Qualcomm I and Qualcomm II “require that only patents and printed publications form the basis of an IPR petition’s unpatentability grounds.” Id. at *4.  It explained that “AAPA can be important evidence of general background knowledge, and general knowledge can be used to supply a missing claim limitation.” Id. (noting precedent has “long recognized numerous permissible uses for general background knowledge in an IPR,” such as providing a motivation to combine or supplying a missing claim limitation, and that the Court in Qualcomm II reiterated that AAPA can be used to show the general knowledge of a person of ordinary skill in the art).  The Court then distinguished the case from Qualcomm II, where the petitioner expressly labeled AAPA as “the basis” for its unpatentability grounds. Id.  Unlike in Qualcomm II, the Court found CSI used AAPA only to show, as Shockwave’s patent itself acknowledges, what was well known in the prior art and that this general background knowledge satisfied certain limitations of the challenged claims. Id.  It found this consistent with precedent that permits general knowledge (or use of AAPA as general knowledge) to supply a missing claim limitation. Id. (quoting and citing Koninklijke Philips N.V. v. Google LLC, 948 F.3d 1330 (Fed. Cir. 2020), Qualcomm I, and Qualcomm II).  It rejected Shockwave’s argument that the case is like Qualcomm II because the FWD used the word “basis” in a table listing the prior art, which included AAPA. Id. (noting the table header is captioned “Reference(s)/Basis”).  The Court said that in Qualcomm II it relied on statements from tables in the petitions that clearly designated AAPA as included in the “basis” of a ground and that its reasoning was predicated on the notion that a petitioner, not the PTAB, “should be held to the phrasing of its petition because [it] is the master of its own petition.” Id.  The Court stated, “What matters for … § 311(b) is the grounds raised in the petition.” Id.  Here, CSI's petition never phrased the AAPA in terms of constituting a basis for its obviousness arguments. Id.  The Court found that, in any event, the “reference(s)/basis” language in the table suggested it encompassed the use of AAPA as a “reference” to establish well-known general knowledge. Id.

The Court also rejected Shockwave’s argument that even if CSI did not label its use of AAPA as a “basis,” in substance AAPA was used to form the basis of the petition. Id.  The Court noted it has not previously decided whether AAPA improperly forms the basis for a petition when used to show that a claim limitation (characterized by the patent as not disclosed in the prior art) would have been obvious over the prior art. Id.  This was not the case here as “CSI properly relied on general background knowledge to supply missing claim limitations (which Shockwave does not argue were novel to the invention) and used AAPA as evidence of that general background knowledge.” Id.  The Court held CSI’s petition did not violate § 311(b) and went on to address other issues Shockwave raised on appeal, as well as CSI’s cross appeal. Id. at *4-9.  Ultimately, the Court affirmed the FWD on unpatentability and reversed as to the one claim not shown unpatentable. Id. at *9.