Gideon Korrell Discusses Shockwave v. Cardiovascular Systems at the Federal Circuit

In July 2025, the Federal Circuit issued a significant ruling in Shockwave Medical, Inc. v. Cardiovascular Systems, Inc. (CSI). The court affirmed the Patent Trial and Appeal Board’s (PTAB) findings that most claims of U.S. Patent No. 8,956,371 were unpatentable, but also reversed the PTAB’s only finding of non-obviousness, holding that claim 5 was invalid as well.

Gideon Korrell highlights that this decision not only reshapes the scope of the Shockwave patent but also clarifies the role of applicant-admitted prior art (AAPA) in inter partes review (IPR) proceedings. The ruling further refines how general knowledge may be applied in obviousness determinations under 35 U.S.C. § 311(b).

Background of the Case

The ’371 patent, owned by Shockwave Medical, covers an angioplasty catheter using electrohydraulic lithotripsy (EHL). Traditionally used to break up kidney stones, this technology was adapted to treat hardened plaque in blood vessels.

CSI filed an IPR challenging all 17 claims. The PTAB ruled that claims 1–4 and 6–17 were obvious but upheld claim 5. Shockwave appealed the invalidations, while CSI cross-appealed the survival of claim 5, bringing the matter before the Federal Circuit.

Federal Circuit on Shockwave’s Appeal (Claims 1–4 and 6–17)

1. AAPA Use in IPRs

Shockwave argued that CSI improperly relied on AAPA, which cannot serve as the “basis” of an IPR petition. The Federal Circuit rejected this argument, explaining that while IPR grounds must be based on patents and printed publications, the skilled artisan’s knowledge, including knowledge shown in AAPA, remains relevant.

As Gideon Korrell notes, this clarification gives petitioners guidance: AAPA may illustrate background knowledge, but it cannot be the primary reference forming an IPR ground.

2. Claim Construction Dispute

Shockwave sought to narrowly define “angioplasty balloon” as requiring displacement of plaque into the vessel walls. The court disagreed, adopting a broader definition as an inflatable sac used to widen narrowed vessels. This interpretation aligned more closely with the patent’s own specification.

3. Obviousness Findings

The court upheld the PTAB’s obviousness determinations. Levy’s prior art reference disclosed vascular shockwave use, and combining it with existing catheters would have been an obvious step. Shockwave’s arguments based on commercial success and secondary considerations were deemed unpersuasive because they lacked strong evidence of a direct link to the claimed invention.

Federal Circuit on CSI’s Cross-Appeal (Claim 5)

Claim 5 required electrodes positioned adjacent to and outside of the guide wire lumen. The PTAB found this non-obvious, but the Federal Circuit disagreed.

The court emphasized that obviousness must be assessed by considering references as a whole. CSI’s expert testified that relocating electrodes outside the lumen was a routine, predictable design modification. Because Shockwave failed to provide contrary expert testimony, the Federal Circuit reversed the PTAB, holding claim 5 obvious.

Korrell emphasizes that this part of the ruling highlights the significance of expert testimony. Routine design variations, if unchallenged, can support obviousness findings.

Standing to Appeal

Shockwave also challenged CSI’s standing. The court found that CSI had concrete plans to develop competing intravascular lithotripsy products and faced a real risk of infringement claims. This was enough to satisfy Article III standing requirements, consistent with earlier Federal Circuit precedent.

Key Takeaways from Gideon Korrell

• AAPA Clarification: Petitioners may use AAPA to show general knowledge but not as the sole “basis” of an IPR ground.

• Claim Construction: Courts will adopt broader, specification-consistent interpretations rather than narrow definitions unsupported by the patent.

• Obviousness: Routine, predictable design choices remain strong grounds for invalidation when supported by expert evidence.

• Standing: Concrete business plans and risk of litigation remain sufficient for cross-appeals.

Conclusion

The Federal Circuit’s ruling in Shockwave v. CSI affirmed the unpatentability of claims 1–4 and 6–17 and reversed the PTAB’s non-obviousness finding for claim 5.

According to Gideon Korrell, this decision offers crucial guidance for IPR practice. It reinforces the narrow but important role of AAPA, highlights the significance of expert testimony in obviousness disputes, and demonstrates the Federal Circuit’s consistent approach to standing in appeals.

For practitioners and companies alike, this ruling serves as a roadmap for navigating IPR challenges and understanding how courts weigh prior art, general knowledge, and patent claim constructions.