Gideon Korrell on Federal Circuit’s Ruling in Shockwave vs. Cardiovascular Systems

Gideon Korrell
1 day ago
3 min read

On July 14, 2025, the Federal Circuit issued an important ruling in Shockwave Medical, Inc. v. Cardiovascular Systems, Inc. This case centered on U.S. Patent No. 8,956,371, which relates to angioplasty catheters using electrohydraulic lithotripsy (EHL) for treating hardened plaque in blood vessels. The court affirmed that most claims were invalid as obvious and reversed the Patent Trial and Appeal Board’s (PTAB) only finding of non-obviousness, holding that claim 5 was also unpatentable.

Gideon Korrell notes that this decision is significant because it clarifies the role of applicant admitted prior art (AAPA) in inter partes review (IPR) and provides guidance on how obviousness should be evaluated under U.S. patent law.

Background of the Case

Shockwave Medical owns the ’371 patent, which adapts shockwave technology—traditionally used in kidney stone treatment—for angioplasty catheters. The catheter uses electrodes in a balloon to create shockwaves, breaking calcified plaque without needing high balloon pressure.

Cardiovascular Systems, Inc. (CSI) challenged all 17 claims of the patent in an IPR. The PTAB found claims 1–4 and 6–17 invalid but upheld claim 5. Shockwave appealed the invalidated claims, while CSI cross-appealed on claim 5.

Federal Circuit’s Ruling on Direct Appeal

The Federal Circuit upheld the PTAB’s invalidation of claims 1–4 and 6–17.

1. Use of AAPA in IPRs

Shockwave argued that CSI improperly used AAPA as a “basis” for its obviousness arguments, which would violate 35 U.S.C. § 311(b). The court disagreed, clarifying that:

Only patents and printed publications can be “bases” in IPRs.
AAPA can still be used as background knowledge to show what a skilled artisan would understand.
This distinction helps petitioners know how far they can rely on AAPA without crossing statutory limits.

2. Claim Construction of “Angioplasty Balloon”

Shockwave tried to narrow the meaning of “angioplasty balloon” to require plaque displacement. The court rejected this, adopting CSI’s broader definition of “an inflatable sac…to widen blood vessels.” The specification itself supported this broader reading.

3. Obviousness Over Prior Art

The court found substantial evidence that:

Levy’s shockwave technique could be applied to angioplasty catheters.
The combination of Levy and general knowledge made the invention predictable.
Shockwave’s claims of commercial success were not strongly tied to the invention.

Cross-Appeal: Claim 5 Is Also Obvious

Claim 5 required electrodes placed adjacent to and outside the guidewire lumen. The PTAB had found this feature non-obvious, but the Federal Circuit reversed.

CSI’s expert explained that moving electrodes outside the lumen was a routine design choice for better coverage.
The court stressed that obviousness must be assessed by considering prior art references together, not in isolation.
Relying on KSR v. Teleflex, the court held that electrode placement was among predictable alternatives available to a skilled artisan.

Thus, claim 5 was also found invalid.

Standing on Appeal

Shockwave argued that CSI lacked standing to cross-appeal. The court rejected this, noting that CSI had concrete plans to commercialize a competing product and faced real risk of litigation from Shockwave. Prior rulings like Adidas v. Nike supported this reasoning.

Key Takeaways from the Decision

The Federal Circuit’s decision provides several lessons for patent practitioners:

AAPA can be used as background knowledge, but not as the “basis” of an IPR ground.
Claim construction matters—courts will look to the specification for guidance.
Obviousness analysis requires viewing prior art combinations as a whole, not piece by piece.
Routine design modifications may render a claim obvious if supported by expert testimony.
Secondary considerations like commercial success must be strongly tied to the claimed invention to carry weight.

Conclusion

In summary, the Federal Circuit:

Affirmed invalidation of claims 1–4 and 6–17,
Reversed the PTAB’s ruling on claim 5,
Confirmed CSI’s standing to cross-appeal.

Gideon Korrell highlights that this case is a roadmap for navigating IPR strategy. It reinforces the careful balance between statutory limits on IPR grounds and the practical use of a skilled artisan’s general knowledge. For patentees, it’s a reminder that overly narrow claim constructions and weak secondary arguments may not survive scrutiny at the appellate level.