CAFC Partially Reverses Abiomed Patent Win, Revives Maquet Infringement Claims

The U.S. Court of Appeals for the Federal Circuit (CAFC) on Monday issued a decision that affirmed in part, vacated in part, and remanded a ruling from the U.S. District Court for the District of Massachusetts in a patent dispute between Maquet Cardiovascular LLC and Abiomed Inc. The Federal Circuit agreed with the lower court that certain claims of one Maquet patent were not infringed by Abiomed’s Impella heart pumps, but revived Maquet’s infringement allegations on five other patents after finding the district court had improperly construed key claim terms.

Abiomed originally filed the lawsuit in May 2016, seeking a court declaration that its Impella devices did not infringe six of Maquet’s patents and that the patents were invalid. The patents at issue, U.S. Patent Nos. 7,022,100, 8,888,728, 9,327,068, 9,545,468, 9,561,314, and 9,597,437 are directed to intravascular blood pump systems and methods for providing heart support. The technology involves placing a small pump within a patient’s circulatory system to assist the heart. Maquet responded to Abiomed’s suit with a counterclaim for patent infringement, seeking damages for the alleged unauthorized use of its patented technology.

In the district court proceedings, Judge F. Dennis Saylor, IV, held a Markman hearing and construed several disputed claim terms in September 2018. Following that order, Maquet narrowed its asserted claims to two claims of the ‘100 patent. In 2021, the district court granted summary judgment to Abiomed, finding no infringement of the ‘100 patent based on its claim construction. Later, the court entered a final judgment of non-infringement on all the asserted patents in September 2023, which prompted Maquet’s appeal to the Federal Circuit, arguing that the lower court had misinterpreted the patent claims.

The CAFC was persuaded by Maquet’s contention that the district court erred by limiting “an elongate lumen associated with the cannula” to merely mean a “lumen formed along the side of the cannula.” The district court had based its narrow construction on statements Maquet made in a related inter partes review (IPR) proceeding, applying the doctrine of prosecution disclaimer. The Federal Circuit, however, found that those statements were not both “clear and unmistakable” as required to invoke the doctrine of prosecution disclaimer. The opinion explained that Maquet’s statements were not “‘words or expressions of manifest exclusion or restriction’” and were a “far too slender a reed to support the judicial narrowing of a clear claim term.”

Moreover, the CAFC also found errors in the district court’s construction of the “purge fluid” limitations. The lower court had determined that the purge fluid “does not go through the rotor bearings and into the bloodstream,” again basing its conclusion on statements from an IPR. The Federal Circuit sided with Maquet, explaining that the district court had improperly imported a negative limitation into the claims. The opinion noted that the patent’s own specification contradicted this construction, explicitly describing that purge fluid can pass through bearing assemblies and into the bloodstream to prevent clotting. The court concluded that Maquet’s IPR statements, which described injecting bearing particles into a patient’s blood as a “bad idea,” were made in the specific context of distinguishing a prior art reference and did not amount to a clear, broad disavowal of claim scope.

However, the Federal Circuit affirmed the district court’s construction of the “guide mechanism” term in the ‘100 patent and agreed that the term was a means-plus-function limitation under 35 U.S.C. § 112, paragraph 6, because the term itself does not recite a sufficiently definite structure. The opinion explained that “mechanism” is a “nonce term”, such as “means,” and the modifier “guide” is purely functional. The court also agreed with the lower court’s identification of the corresponding structures disclosed in the patent’s specification, rejecting Maquet’s argument that additional structures should have been included.

Ultimately, the Federal Circuit upheld the summary judgment of non-infringement for the ‘100 patent. The court found that no reasonable jury could conclude that Abiomed’s Impella devices contained a “guide mechanism” equivalent to the structures disclosed in Maquet’s patent. The opinion noted that the pigtail on the Impella device is not “formed along” the cannula sidewall as the claim construction required, but is instead attached at the distal end. The court also dismissed Maquet’s expert testimony on equivalence as conclusory and insufficient to create a genuine dispute of material fact needed to survive summary judgment.

The Federal Circuit’s decision ultimately vacated the judgment concerning the ‘728, ‘068, ‘468, ‘314, and ‘437 patents and remanded the case to the District of Massachusetts for further proceedings under the corrected, broader claim constructions for “elongate lumen” and “purge fluid.” The non-infringement judgment on the ‘100 patent, however, was upheld, handing a partial victory to both sides.