PTAB

IPR2018-01658

Cardiovascular Systems Inc v. Cardio Flow Inc

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Rotational Atherectomy Device with Eccentric Abrasive Element and Method of Use
  • Brief Description: The ’362 patent discloses a method and system for treating arterial stenosis. The system utilizes a rotational atherectomy device featuring an eccentric abrasive element mounted on a flexible drive shaft, which is flanked by proximal and distal stability elements intended to control the device's orbital motion during high-speed rotation within a blood vessel.

3. Grounds for Unpatentability

Ground 1: Obviousness over Carbo in view of Kallok or Prudnikov - Claims 1-4 and 7-11 are obvious over Carbo in view of Kallok or, alternatively, Prudnikov.

  • Prior Art Relied Upon: Carbo (Patent 5,250,060), Kallok (Patent 8,177,801), and Prudnikov (Patent 8,348,965).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Carbo taught the foundational method for treating an iliac artery, including positioning an elongate catheter with two lumens and an inflatable balloon member to seal off a vessel section. Carbo further disclosed rotating a drive cable within the catheter to perform atherectomy. Petitioner contended, however, that Carbo did not explicitly teach the specific configuration of the atherectomy device claimed in the ’362 patent. This missing configuration—an eccentric abrasive element mounted on the drive shaft between a pair of proximal and distal stability elements, with the drive shaft extending beyond the distal stability element—was expressly taught by both Kallok and Prudnikov.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the teachings by substituting the rotational cutter in Carbo’s system with the more advanced eccentric abrasive element and stability element system taught by Kallok or Prudnikov. The motivation for this modification was the known and predictable result of achieving a larger effective working diameter than the resting diameter of the device, thereby enabling more efficient removal of occlusions.
    • Expectation of Success: Petitioner asserted success would be expected because the combination involved the simple substitution of one known rotational removal mechanism for another to achieve a well-understood and predictable improvement in performance.

Ground 2: Obviousness over Shturman ’458 in view of Kallok or Prudnikov - Claims 1-4 and 7-11 are obvious over Shturman ’458 in view of Kallok or, alternatively, Prudnikov.

  • Prior Art Relied Upon: Shturman ’458 (UK Publication No. GB 2,426,458), Kallok (Patent 8,177,801), and Prudnikov (Patent 8,348,965).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner presented Shturman ’458 as a stronger primary reference that disclosed nearly all elements of the challenged claims in a single device. Shturman ’458 taught a method of rotational atherectomy using a device with an eccentric abrasive element and a pair of stability elements (termed “counterweights”) fixed proximally and distally to the abrasive element. To the extent that Shturman ’458 did not explicitly disclose the drive shaft extending distally beyond the second stability element—a feature added during prosecution of the ’362 patent to secure allowance—Petitioner argued this feature was clearly taught by both Kallok and Prudnikov.
    • Motivation to Combine: A POSITA would be motivated to modify the device in Shturman ’458 to include the distally extending drive shaft portion shown in Kallok or Prudnikov. This modification would have been recognized as an obvious design choice to improve the device’s function. The extended, flexible portion of the drive shaft would act as a lead guide over a pre-positioned guidewire, improving navigation through tortuous vasculature and enhancing the stability of the abrasive element during high-speed rotation.
    • Expectation of Success: Success was expected because incorporating a known guiding and stabilizing feature (the extended drive shaft) from one atherectomy device (Kallok/Prudnikov) into a very similar device (Shturman ’458) was a straightforward design modification with predictable benefits.

  • Additional Grounds: Petitioner asserted further obviousness challenges for claims 5 and 6. For claim 5, the combination of either Carbo or Shturman ’458 with Kallok/Prudnikov was combined with Rydell (Patent 4,784,636) to teach the step of deflating and repositioning the device. For claim 6, the same base combinations were combined with Maschke (Application # 2007/0066888) to teach the use of an intravascular ultrasound imaging catheter to acquire cross-sectional images of the lesion.

4. Key Claim Construction Positions

  • “stability element”: Petitioner argued a POSITA would understand this term to mean “a component of a device capable of exerting opposing force to provide a stable and predictable motion.” Crucially, Petitioner contended that this term was interchangeable with the term “counterweight” used throughout the ’362 patent’s specification and in prior art references like Prudnikov. This interchangeability was central to mapping the prior art, as the term “stability element” was not used in the original specification and was only introduced during prosecution.
  • “abrasive element”: Petitioner proposed this term be construed as “a component of a device capable of removing material by grinding or rubbing.” This construction aligns the claimed element with the “abrasive burr” described in the specification and disclosed in the prior art.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-11 of the ’362 patent as unpatentable under 35 U.S.C. §103.