Cardiovascular Systems, Inc. v. Cardio Flow, Inc.

1. Case Identification

• Patent #: 9,788,853
• Filed: August 17, 2018
• Petitioner(s): Cardiovascular Systems, Inc.
• Patent Owner(s): Cardio Flow, Inc.
• Challenged Claims: 1-15

2. Patent Overview

• Title: Atherectomy Devices and Methods
• Brief Description: The '853 patent describes a rotational atherectomy system for removing stenotic lesions from blood vessels. The system features an elongated drive shaft with an eccentric abrasive element designed to create a large orbital path during high-speed rotation, combined with weighted stability elements intended to ensure the motion is stable and predictable.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claims 1-10 and 12-14

• Legal Basis: Claims 1-10 and 12-14 are obvious under 35 U.S.C. §103 over Shturman ’633 in view of Kallok and at least one of Narveson, Cambronne, Shturman ’444, and Wulfman.
• Prior Art Relied Upon: Shturman (Application # 2012/0035633, the ’633 application), Kallok (Patent 8,177,801), Narveson (Patent 8,628,550), Cambronne (Patent 9,289,230), Shturman (Patent 6,132,444, the ’444 patent), and Wulfman (Patent 5,584,843).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Shturman ’633 discloses the foundational system: a rotational atherectomy device with a drive shaft, an eccentric abrasive element, and stability elements. The secondary references were used to supply features for a complete mapping to the claims. Kallok was cited for its teaching of using concentric stability elements (or counterweights) to stabilize the rotation of an eccentric abrasive element. Narveson, Cambronne, and Wulfman were cited to show that using multiple, spaced-apart abrasive elements was a known technique to enlarge the cutting area and improve flexibility. Petitioner contended that modifying Shturman ’633 to have multiple abrasive elements was a mere duplication of parts.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these known elements to achieve predictable improvements. A POSITA would modify Shturman ’633’s device with Kallok’s concentric stability elements to improve rotational stability, a known goal in the field. Likewise, a POSITA would incorporate the teachings of Narveson, Cambronne, or Wulfman to use multiple abrasive heads to increase the abrasive surface and enhance shaft flexibility, which were recognized advantages.
  • Expectation of Success: Petitioner asserted a high expectation of success, as the combination relied on applying well-understood principles of rotational mechanics. The effects of mass, eccentricity, and counterweights on orbital motion were known and mathematically predictable, ensuring the combined device would function as expected.

Ground 2: Obviousness of Claim 11

• Legal Basis: Claim 11 is obvious over the combination for Ground 1, further in view of Liprie.
• Prior Art Relied Upon: The references from Ground 1, plus Liprie (Patent 5,556,389).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the arguments for claim 1. Claim 11 adds a balloon member with channel spaces configured to allow blood flow past the balloon when inflated. While Shturman ’633 discloses an occlusion balloon, Petitioner argued it does not explicitly teach perfusion channels. Liprie taught an angioplasty balloon with precisely such channels, designed to allow blood flow during inflation.
  • Motivation to Combine: A POSITA would be motivated to modify the balloon in Shturman ’633 with the perfusion feature from Liprie to improve patient safety. Allowing blood to flow past the device during an atherectomy procedure was a known method to reduce the risk of ischemia or myocardial infarction.

Ground 3: Obviousness of Claim 15

• Legal Basis: Claim 15 is obvious over the combination for Ground 1, further in view of Campbell.
• Prior Art Relied Upon: The references from Ground 1, plus Campbell (Application # 2012/0178986).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the arguments for claims 1 and 13 (which adds a polymer coating). Claim 15 specifies that the flexible polymer coating has a different durometer at different locations on the drive shaft. Campbell was cited for teaching a percutaneous medical device with a rotational drive shaft covered by a flexible polymer coating with exactly this feature—a variable durometer.
  • Motivation to Combine: A POSITA would find it obvious to incorporate Campbell's variable durometer coating onto the device of the primary combination. This modification represented a routine design choice to optimize the drive shaft's physical properties, providing greater stiffness where needed and more flexibility in other areas to better navigate tortuous blood vessels.

4. Key Claim Construction Positions

• Petitioner proposed constructions for several key terms to align them with the disclosures in the prior art.
• • "Stability element": Argued to be synonymous with "counterweight," a term used in references like Kallok, to directly link the claim language to the prior art's stabilizing components.
• • "Spherical": Construed broadly to mean "relating to or having properties of a sphere," not requiring a perfect geometric shape. This construction was intended to encompass the sphere-like abrasive elements disclosed in the prior art.
• • "Cylindrical": Similarly construed broadly as "relating to or having similarity to a cylinder" to avoid a narrow interpretation that would exclude prior art components that were not perfect cylinders.

5. Key Technical Contentions (Beyond Claim Construction)

• The petition’s central technical contention was that the ’853 patent claims routine combinations of known elements from a finite set of predictable solutions in the field of atherectomy device design.
• Petitioner consistently argued that the principles governing orbital motion—specifically, using an eccentric mass (abrasive element) balanced by concentric masses (stability elements) to create a stable, enlarged cutting path—were well-established and produced mathematically predictable effects, rendering the claimed combinations obvious to a POSITA.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-15 of the '853 patent as unpatentable under 35 U.S.C. §103.