Shockwave Med., Inc. v. Cardiovascular Sys
Authored by: Jeremy J. Gustrowsky
In the recent case of Shockwave Medical, Inc. v. Cardiovascular Systems, Inc., the Federal Circuit addressed how “Applicant Admitted Prior Art” (AAPA) can be used in patent challenges before the Patent Trial and Appeal Board (PTAB). The dispute centered on U.S. Patent No. 8,956,371, which covers a special type of balloon catheter for breaking up hardened plaque in blood vessels using shockwaves—a technique known as intravascular lithotripsy (IVL). Cardiovascular Systems, Inc. (CSI) challenged all 17 claims of this patent, arguing they were obvious in light of prior art, including AAPA and several published patents.
A key issue was whether AAPA—statements in a patent about what was already known—could be used as the main basis for invalidating a patent in an inter partes review (IPR). The court clarified that while AAPA cannot be the “basis” of an IPR petition under the law, it can be used as evidence of what was generally known in the field to help fill in missing pieces of the puzzle. In this case, CSI used AAPA only to show that certain types of balloon catheters were already well-known, which the court found acceptable.
The court also looked at whether the PTAB correctly interpreted the term “angioplasty balloon” and whether there was enough evidence to support its findings on obviousness. The Federal Circuit agreed with the PTAB’s construction, stating that nothing in the patent required the balloon to press plaque into the vessel wall. It also found that the PTAB had substantial evidence for most of its obviousness findings. However, the court reversed the PTAB’s decision on claim 5, finding that the Board failed to consider the combined teachings of the prior art and improperly dismissed the argument that the placement of electrodes was a routine design choice.
Ultimately, the Federal Circuit affirmed the PTAB’s decision that claims 1-4 and 6-17 were unpatentable but reversed its decision on claim 5, ruling that it too was obvious. This case is important for applicants as it highlights risks in including discussions about prior art in one’s own application. The case also gives further insight for litigants on how AAPA can be used and underscores the need for the PTAB to consider all relevant prior art as a whole.