PTAB

IPR2019-00409

Cardiovascular Systems Inc v. Shockwave Medical Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Shockwave Catheter System With Energy Control
  • Brief Description: The ’091 patent discloses a catheter system for treating calcified lesions in blood vessels. The system uses a pair of electrodes within a fluid-filled balloon to generate an electrical arc, creating a shockwave that disrupts the lesion. The invention focuses on a control system that monitors the current between the electrodes and terminates the voltage pulse when the current reaches a predetermined threshold to control the energy delivered.

3. Grounds for Unpatentability

Ground 1: Claims 1-14 are obvious over Hawkins in view of Li

  • Prior Art Relied Upon: Hawkins (2009/0312768) and Li (2006/0221528).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hawkins teaches all elements of the challenged claims except for an explicit current sensor that terminates voltage pulses. Hawkins discloses a shockwave balloon catheter for treating calcified lesions but relies on reflected energy for feedback. Li, a reference from the field of pulsed power supplies, discloses an over-current protection circuit that senses when current exceeds a predetermined threshold and terminates (or narrows) the voltage pulse on a pulse-by-pulse basis to prevent damage.
    • Motivation to Combine: A POSITA would combine Li's known over-current protection circuit with Hawkins's electrohydraulic lithotripsy (EHL) catheter to improve safety and reliability. This combination would prevent excessive current from damaging the device or causing trauma to the patient, representing a predictable application of a known safety solution to a known problem in pulsed-power devices.
    • Expectation of Success: A POSITA would have a high expectation of success, as incorporating a standard current-limiting feedback loop into a pulsed power system like Hawkins’s involves applying well-understood electrical engineering principles.

Ground 2: Claims 1-3 and 10 are obvious over Hawkins in view of Chernenko

  • Prior Art Relied Upon: Hawkins (2009/0312768) and Chernenko (2003/0176873).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Chernenko, a reference disclosing an EHL device for treating arterial calculi, remedies the deficiencies of Hawkins by explicitly teaching a feedback control system with a current sensor. Chernenko's system terminates the voltage supply as soon as a current threshold indicating spark formation ("dielectric breakdown") is detected for an individual pulse. Petitioner contended that during the original prosecution, the Examiner misunderstood Chernenko’s teachings due to misleading arguments from the Patent Owner.
    • Motivation to Combine: A POSITA would be motivated to incorporate Chernenko's specific current-sensing control into the Hawkins catheter to achieve more precise control over the shockwave generation. The stated benefits in Chernenko—including increased patient safety, control of calcified fragments, and reduced trauma from excess energy—would provide a strong reason to apply its pulse-by-pulse termination logic to a similar EHL device like Hawkins.
    • Expectation of Success: Both references operate in the same technical field of EHL devices, making the integration of Chernenko’s control system into Hawkins’s device straightforward and predictable.

Ground 3: Claims 1-14 are obvious over Hawkins in view of Heeren

  • Prior Art Relied Upon: Hawkins (2009/0312768) and Heeren (2013/0041355).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Heeren, a reference for pulsed-electric field (PEF) surgical devices that was not before the Examiner, discloses using a current sensor to detect dielectric breakdown. Upon sensing a sudden current increase that exceeds a predetermined threshold, Heeren’s system dynamically adjusts or terminates the electrical pulse to control the negative effects of the breakdown.
    • Motivation to Combine: A POSITA would have looked to the analogous art of PEF surgical devices to solve problems of controlling high-current pulses. A POSITA would combine Heeren’s dynamic, current-based feedback control with Hawkins’s EHL device to reduce patient damage, increase the device's electrical efficiency, decrease component wear, and provide safer operation. This combination represents the application of a known control technique from a pertinent field.
    • Expectation of Success: Applying Heeren's current-threshold feedback control to each spark-generating pulse in Hawkins's device would be a predictable implementation to achieve safer and more efficient operation for each shockwave.

  • Additional Grounds: Petitioner asserted that claims 1-14 are also obvious over Hawkins as modified by Chernenko and further in view of Li. This ground argued that Li provides additional, specific control implementations that complement Chernenko’s teachings and further motivate the modification of Hawkins.

4. Key Claim Construction Positions

  • “predetermined value”: Petitioner proposed this term be construed to mean "a value set in advance." This construction is consistent with its plain meaning and the specification’s example of a 50-ampere current limit. Petitioner argued this construction demonstrates that standard threshold-based circuits in the prior art meet the claim limitation.
  • “predetermined delay time”: Petitioner proposed this term be construed to mean "a delay time set in advance." The petition argued that the patent does not limit this term to a specific duration (e.g., 100 nanoseconds) and that it covers delay times inherent in or set by the control circuits disclosed in the prior art.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-14 of the ’091 patent as unpatentable under 35 U.S.C. §103.