PTAB

IPR2017-01426

Visionsense Corp v. NOvadaq Technologies Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and apparatus for performing intra-operative angiography
  • Brief Description: The ’190 patent relates to a method for assessing blood flow and patency in a vessel graft during a surgical procedure. The method involves administering a fluorescent dye, illuminating the surgical site, and using a camera to capture a series of images showing the "wavefront" of the dye as it first enters and transitions through the graft and interconnected blood vessels.

3. Grounds for Unpatentability

Ground 1: Claims 1 and 2 are anticipated by Little.

  • Prior Art Relied Upon: Little (a 1979 article in the Journal of Neurosurgery).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Little, a 1979 publication, discloses every limitation of claims 1 and 2. Little described an intraoperative method for assessing the patency of a cerebral artery graft using fluorescein dye angiography. The article detailed administering a fluorescent dye (sodium fluorescein), exciting the dye with a strobe light, and capturing a series of "rapid, serial photographs" with a motorized camera that showed the dye wavefront transitioning through the graft. The images were then evaluated to assess blood flow. For claim 2, Little explicitly described cases where the angiogram revealed an occlusion, prompting clinicians to make corrective surgical modifications to improve blood flow, thereby teaching the "modifying step."

Ground 2: Claims 1-3 are obvious over Little in view of Flower I and Flower II.

  • Prior Art Relied Upon: Little (1979 journal article), Flower I (Patent 6,351,663), and Flower II (Patent 5,394,199).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Little taught the foundational method of assessing a vessel graft using fluorescence angiography. The Flower references supplied the specific technical details required by claim 3, rendering it obvious. Specifically, Flower I and Flower II taught the use of Indocyanine Green (ICG) as a "preferred" and "readily available" fluorescent dye, which has the peak absorption and emission spectrum in the 800-850 nm range required by claim 3. The Flower patents also disclosed using a conventional CCD video camera to capture angiograms at "high speeds (15-30 images/second)," which meets the requirement of imaging at least 15 images per second.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine the teachings to improve upon Little's decades-old method. A POSITA would replace the fluorescein dye used in Little with the clinically superior ICG dye taught by Flower, as ICG is cleared from the bloodstream much faster, allowing for rapid repeat imaging sequences after a surgical correction. Furthermore, a POSITA would replace Little's cumbersome film camera with the modern CCD video camera taught by Flower to gain the advantages of real-time viewing, easier recording and playback, and elimination of film development delays.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination merely applied a known, superior dye and imaging system to a well-understood surgical assessment procedure to achieve a predictable improvement in convenience and clinical utility.

Ground 3: Claims 1-3 are obvious over Jibu in view of Flower I and Little or Goldstein.

  • Prior Art Relied Upon: Jibu (Japanese Publication H9-309845), Flower I (Patent 6,351,663), and Little (1979 journal article) or Goldstein (a 1998 journal article).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Jibu, a reference used to invalidate parallel foreign patents, discloses a complete system for intraoperative, near-infrared fluorescence imaging that renders the claimed method obvious when applied to the known surgical context of assessing vessel grafts. Jibu taught administering an ICG tracer, illuminating it, and detecting fluorescence with a CCD camera system capable of frame rates exceeding 15 images per second. Jibu's disclosure of ICG fluorescing at 835 nm met the wavelength requirement of claim 3. The references Little and Goldstein established that assessing vessel graft patency intraoperatively (on cerebral and coronary grafts, respectively) was a known clinical need.
    • Motivation to Combine: A POSITA would be motivated to apply the advanced, convenient, and inexpensive real-time imaging system disclosed in Jibu to the specific and well-known surgical applications described in Little and Goldstein. Jibu itself suggested use during surgery due to "convenience and inexpensiveness." Applying Jibu's superior imaging technology to the established problem of assessing graft patency would have been a natural and predictable step for improving surgical outcomes.
    • Expectation of Success: Success would be highly expected, as it involved using an imaging system designed for real-time surgical use for its intended purpose in a known surgical scenario.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 3) based on Flower I and Flower II in view of Little or Goldstein. This ground relied on similar arguments, contending that the general methods for fluorescence imaging of blood vessels in Flower would have been obviously applied to the specific vessel graft contexts taught by Little and Goldstein.

4. Key Claim Construction Positions

  • Petitioner argued that under the broadest reasonable construction, the claim terms are not limiting in a way that would avoid the prior art. Petitioner noted the following interpretations:
    • "Vessel graft" is not limited to a specific type of vessel and can include grafts in the leg, heart, or brain.
    • "Animal" can be a human or non-human animal.
    • The method of exciting the dye is not limited to a specific source (e.g., laser, strobe light).
    • The amount of "fluorescent dye" is not limited, nor is the method of administration (e.g., single bolus or multiple administrations).

7. Relief Requested

  • Petitioner requests institution of an IPR and cancellation of claims 1-3 of the ’190 patent as unpatentable.