| August 13, 2025
Shocking-Applicant Admitted Prior Art Sinks Own Patent
Case Name: SHOCKWAVE MEDICAL, INC. v. CARDIOVASCULAR SYSTEMS, INC.
Decided: July 14, 2025
Before: LOURIE, DYK, and CUNNINGHAM, opinion by DYK
Background
Shockwave owns US patent no. 8,956,371 directed to treatment of atherosclerosis through intravascular lithotripsy. Lithotripsy is a technique used to break up kidney stones by using shockwaves induced by plasma. Atherosclerosis is a buildup of fatty deposits in blood vessels. Balloon angioplasty is a method of treating atherosclerosis by guiding a balloon catheter to the location of a blood vessel containing calcified plaque buildup.
Shockwave’s claimed device uses a typical over-the-wire angioplasty balloon catheter and adds electrodes within a fluid-filled balloon with a pulse generator to generate shockwaves to break up calcified plaque deposits. Claims 1 and 5 state:
1. An angioplasty catheter comprising: an elongated carrier sized to fit within a blood vessel,
said carrier having a guide wire lumen extending there through;
an angioplasty balloon located near a distal end of the carrier with a distal end of the balloon being sealed to the carrier near the distal end of the carrier and with a proximal end of the balloon defining an annular channel arranged to receive a fluid therein that inflates the balloon; and
an arc generator including a pair of electrodes, said electrodes being positioned within and in non-touching relation to the balloon,
said arc generator generating a high voltage pulse sufficient to create a plasma arc between the electrodes resulting in a mechanical shock wave within the balloon that is conducted through the fluid and through the balloon and wherein the balloon is arranged to remain intact during the formation of the shockwave.
5. The catheter of claim 2, wherein the pair of electrodes is disposed adjacent to and outside of the guide wire lumen.
Claim 2 requires that the “pair of electrodes” include a “pair of metallic electrodes.
CSI filed an inter partes review (IPR) petition challenging all claims of Shockwave’s ‘371 patent as obvious over EP 0571306 to Levy. The EP patent describes using laser-generated pulses to disintegrate plaque in blood vessels. CSI’s petition pointed to Shockwave’s ‘371 patent disclosure discussing “typical prior art over-the-wire angioplasty balloon catheter[s] … [that] are usually non-compliant with a fixed maximum dimension when expanded with a fluid such as saline.” The petition argued that it would have been obvious to modify Levy with the well-known angioplasty balloon catheter disclosed by the applicant admitted prior art (AAPA). (Keep in mind that a rejection in an IPR petition can only be based on patents and printed publications).
The Patent Trian and Appeal Board (PTAB) issued a final decision finding claims 1-4 and 6-17 were unpatentable as obvious. The PTAB stated that AAPA qualified as “prior art consisting of patents or printed publications.” After the decision, the USPTO issued “AAPA Guidance” stating that AAPA is not “prior art consisting of patents or printed publications.” The PTAB thereafter initiated rehearing, relying on AAPA only as evidence of the background knowledge in the art to typical over-the-wire balloon catheters. The PTAB then again concluded that claims 1-4 and 6-17 had been shown to be unpatentable as obvious.
Shockwave appealed the finding of unpatentability while CSI appealed the finding that claim 5 was not unpatentable.
Discussion
AAPA as a basis vs. evidence in an IPR petition
Shockwave argued that both CSI and the PTAB improperly relied on AAPA as a basis for the IPR petition. As set forth in 35 U.S.C. 311(b), a petitioner in an inter partes review may request to cancel as unpatentable 1 or more claims of a patent only on a ground that could be raised under section 102 or 103 and only on the basis of prior art consisting of patents and printed publications. The Federal Circuit has explained that “[a]lthough the prior art that can be considered in [IPRs] is limited to patents and printed publications, it does not follow that we ignore the skilled artisan’s knowledge when determining whether it would have been obvious to modify the prior art.” Koninklijke Philips N.V. v. Google LLC, 948 F.3d 1330, 1337 (Fed. Cir. 2020). This is because the obviousness analysis “requires an assessment of the . . . ‘background knowledge possessed by a person having ordinary skill in the art.’” Dow Jones & Co. v. Ablaise Ltd., 606 F.3d 1338, 1349 (Fed. Cir. 2010) (quoting KSR Int’l Co. v. Teleflex, Inc., 550 U.S. 398, 401 (2007)).
As set forth in Qualcomm Incorporated v. Apple Inc., 24 F.4th 1367 (Fed. Cir. 2022) (“Qualcomm I”), AAPA can be used as evidence of background knowledge of an ordinarily skilled artisan, but that AAPA cannot be the “basis” of a ground in an IPR petition. Shockwave had noted that the PTAB’s written decision included a table with a column labeled Relevance/Basis to assert that the AAPA was the basis of the ground of rejection. The CAFC, however, distinguished the reference to “basis” by noting that it is an IPR petitioner, not the PTAB, that must comply with what defines the metes and bounds of an IPR. Here, CSI properly relied on general background knowledge to supply missing claim limitations and used AAPA as evidence of that general background in the IPR petition. As such, the IPR petition did not violate section 311(b).
Claim construction of “angioplasty balloon”
Shockwave argues that the Board erred in denying its construction for “angioplasty balloon” as “a balloon that displaces the plaque into the vessel wall to expand the lumen of the vessel” and adopting CSI’s construction of the term as “an inflatable sac that is configured to be inserted into a blood vessel for use in a medical procedure to widen narrowed or obstructed blood vessels.” This argument was dismissed because there is nothing in the language of the claims or specification which supports requiring that an angioplasty balloon press plaque into the vessel wall.
Challenge to Fact Findings
Shockwave challenges three of the PTAB’s fact findings: (1) that an ordinarily skilled artisan would have been motivated to incorporate Levy’s shockwave system into the over-the-wire balloon catheter, (2) that Levy discloses shockwaves, and (3) that Shockwave’s secondary considerations evidence did not outweigh CSI’s obviousness showing. The standard of review for fact findings is substantial evidence. The CAFC found that substantial evidence supports each of the findings.
CSI’s Cross-Appeal
CSI cross-appeals the PTAB’s conclusion that claim 5 had not been shown to be unpatentable as obvious over Levy implemented in an over-the-wire balloon catheter in view of Uchiyama. The PTAB found that the prior art combination did not disclose claim 5’s limitation relating to the placement of electrodes.
Initially, Shockwave argued that CSI lacks Article III standing. As we have discussed in other decisions related to Article III standing, a party does not need Article III standing to receive a PTAB decision, but does need Article III standing to seek review of a PTAB decision. Parties seeking relief before the CAFC have the burden of establishing the existence of an Article III case or controversy. Regarding this, when a party challenging an IPR decision “relies on potential infringement liability as a basis for injury in fact, but is not currently engaging in infringing activity, it must establish that it has concrete plans for future activity that creates a substantial risk of future infringement or would likely cause the patentee to assert a claim of infringement.” Gen. Elec. Co. v. Raytheon Techs. Corp., 983 F.3d 1334, 1341 (Fed. Cir. 2020) (quoting JTEKT Corp. v. GKN Auto, LTD., 898 F.3d 1217, 1221 (Fed. Cir. 2018)).
CSI says it has standing because it has developed an intravascular lithotripsy (IVL) device, and Shockwave’s President publicly commented that the company would aggressively assert claim 5:
We are very pleased that the [Board] validated claim 5 of our ’371 patent, which protects the broad embodiment of our IVL technologies. Specifically, claim 5 describes a device that is delivered over a guidewire and generates shockwaves with electrodes inside of a balloon catheter. We believe that any viable, much less commercially viable, IVL device must contain these elements[.] . . . We believe that our robust portfolio of 40 issued U.S. patents and 50 issued foreign patents captures and protects the truly unique and sophisticated IVL technology[.]
The CAFC found that CSI’s circumstances had constituted sufficiently concrete plans coupled with a substantial likelihood of a suit of infringement of claim 5. Shockwave’s President’s statement reflected the company’s view of claim 5 as reading broadly on IVL technology, and that CSI had sufficiently shown that it was engaging in activity that creates a substantial risk of future infringement to likely cause the patentee to assert infringement.
Regarding obviousness of claim 5, the CAFC found that the PTAB’s analysis was predicated on the teaching of a prior art reference Uchiyama alone as not disclosing electrodes positioned adjacent to and outside of the guidewire lumen. The standard of obviousness requires consideration of the prior art combination as a whole (that is, the combination of Levy with Uchiyama). CSI’s expert had testified that it would have been obvious to implement the features of Uchiyama as a routine design choice. Shockwave did not present contrary evidence. Since there was no evidence in the record supporting the finding as to claim 5, the PTAB is reversed.
Takeaways
- Avoid having an admission of prior art in your specification. If there is prior art disclosing a certain aspect that serves as a background of the invention, refer to that prior art itself instead of creating an admission.
- AAPA cannot be used as a basis of an IPR petition, but can be used as evidence of the state of art.
- Advise your clients to refrain from making statements following a PTAB decision. The President’s statement allowed CSI to establish standing to file the cross appeal which ultimately struck down the last standing claim.
- Expert testimony is important in any IPR petition. CSI had expert testimony regarding obviousness of claim 5 which was not refuted by testimony from Shockwave.
