PTAB

IPR2018-01549

Cardiovascular Systems Inc v. Cardio Flow Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Atherectomy Devices and Methods
  • Brief Description: The ’853 patent discloses a rotational atherectomy device for removing or reducing stenotic lesions in blood vessels. The system uses an elongated flexible drive shaft with an eccentric abrasive element and weighted stability elements, where the abrasive element’s center of mass is offset from the shaft's axis and the stability elements' center of mass is aligned with it, enabling stable rotation with an orbital path larger than the device's resting diameter.

3. Grounds for Unpatentability

Ground 1: Obviousness over Shturman ‘633, Kallok, and Additional Art - Claims 1-10 and 12-14 are obvious over Shturman ‘633 in view of Kallok and at least one of Narveson, Cambronne, Shturman ‘444, and Wulfman.

  • Prior Art Relied Upon: Shturman ‘633 (Application # 2012/0035633), Kallok (Patent 8,177,801), Narveson (Patent 8,628,550), Cambronne (Patent 9,289,230), Shturman ‘444 (Patent 6,132,444), and Wulfman (Patent 5,584,843).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the primary reference, Shturman ‘633, discloses the foundational rotational atherectomy system, including a flexible drive shaft, an eccentric abrasive element, and stability elements (termed "counterweights"). To meet the limitation of "at least three spherical abrasive elements" in claim 1, which Shturman ‘633 does not explicitly teach, Petitioner asserted it would be obvious to multiply the single abrasive element. This modification is taught by Narveson (multiple adjacent abrasive elements for flexibility and control), Cambronne (multiple spaced-apart eccentric heads), and Wulfman (multiple burrs to enlarge the cutting area). To meet the limitation that the stability element has a center of mass aligned with the longitudinal axis (i.e., is concentric), Petitioner combined Shturman ‘633 with Kallok, which explicitly discloses using concentric counterweights proximally and distally to an eccentric abrasive element to increase stability. Shturman ‘444 was also cited as teaching concentric metallic markers that serve a stability function. Arguments for dependent claims followed similar logic, incorporating features shown in the combination.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the teachings of Shturman ‘633 with Narveson, Cambronne, or Wulfman as a routine design choice to achieve the known benefits of enlarging the cutting area, enhancing flexibility, and improving control over orbital motion. A POSITA would combine Shturman ‘633 with Kallok or Shturman ‘444 to improve the stability and predictability of the device’s rotation, a well-understood principle for controlling an eccentric rotating mass.
    • Expectation of Success: Petitioner asserted a high expectation of success, as the principles of using multiple abrasive elements and balancing eccentric masses with concentric counterweights were well-known and produced predictable results. Narveson, for instance, explicitly discusses the mathematically predictable effects of such modifications.

Ground 2: Obviousness of Claim 11 (Perfusion Balloon Feature) - Claim 11 is obvious over the combination of Ground 1 in view of Liprie.

  • Prior Art Relied Upon: The combination for Ground 1, plus Liprie (Patent 5,556,389).
  • Core Argument for this Ground:
    • Prior Art Mapping: Claim 11 adds a balloon member with channel spaces configured to allow blood flow past the balloon when inflated. While Shturman ‘633 teaches an "occlusion balloon," it does not disclose a perfusion feature. Liprie was introduced to teach an angioplasty balloon with channels that allow blood to perfuse while the balloon is inflated.
    • Motivation to Combine: A POSITA would be motivated to modify the occlusion balloon of Shturman ‘633 with the perfusion feature taught by Liprie to improve patient safety by maintaining blood flow during the atherectomy procedure, thereby reducing the risk of myocardial infarction. This was argued to be an obvious improvement to address a known clinical need.
    • Expectation of Success: Combining a known perfusion balloon design with an atherectomy catheter was presented as a straightforward integration of known components for their intended and predictable functions.

Ground 3: Obviousness of Claim 15 (Variable Durometer Coating) - Claim 15 is obvious over the combination of Ground 1 in view of Campbell.

  • Prior Art Relied Upon: The combination for Ground 1, plus Campbell (Application # 2012/0178986).
  • Core Argument for this Ground:
    • Prior Art Mapping: Claim 15, which depends from claim 13, requires a flexible polymer coating on the drive shaft that has a "different durometer at different locations." The petition first established the obviousness of claim 13’s polymer coating by citing WO 2006/126076 (referenced in Shturman ‘633), which teaches a fluid-impermeable polymer membrane on a drive shaft. For the variable durometer limitation of claim 15, Petitioner relied on Campbell, which teaches a rotational drive shaft with a flexible polymer coating having different durometers at different locations.
    • Motivation to Combine: A POSITA would be motivated to incorporate a variable durometer coating, as taught by Campbell, onto the drive shaft of the primary combination to optimize the device's mechanical properties. This would provide greater stiffness for torque transmission in proximal sections while allowing greater flexibility in distal sections for navigating tortuous vessels, a common and well-understood design principle for catheters.

4. Key Claim Construction Positions

  • "spherical": Petitioner proposed the construction "relating to or having properties of a sphere," arguing it describes a shape for the abrasive element that is not strictly limited to a perfect sphere but includes sphere-like shapes.
  • "stability element": Petitioner proposed "a component of a device capable of exerting opposing force to provide a stable and predictable motion." This construction was argued to be synonymous with the term "counterweight" used in the prior art, such as Shturman ‘633 and Kallok.
  • "cylindrical": Petitioner proposed "relating to or having similarity to a cylinder," including shapes with generally straight parallel sides and a circular or ovular cross-section, not strictly limited to a perfect cylinder.

5. Relief Requested

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