Ex Parte Wang et al

Patent Trial and Appeal Board

Sep 27, 2012

10684759 (P.T.A.B. Sep. 27, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte LI WANG, YONG K. CHO, KEVIN KUEHN,
GLENN C. ZILLMER, and NIRAV V. SHETH
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Appeal 2011-012933
Application 10/684,759
Technology Center 3700
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Before LORA M. GREEN, JEFFREY N. FREDMAN, and
STEPHEN WALSH, Administrative Patent Judges.

WALSH, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134(a) from the rejection of
claims directed to a method for monitoring intra-thoracic fluid content and to
an implantable device. The Patent Examiner rejected the claims for
obviousness. We have jurisdiction under 35 U.S.C. § 6(b). We reverse.
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STATEMENT OF THE CASE
Claims 80-82, 84-87, and 96-103 are on appeal. Claim 80 illustrates
the subject matter:
80. A method for monitoring intra-thoracic fluid content using an
implanted cardiac stimulation device comprising at least two implanted
electrodes, the method comprising:
responsive to occurrence of a cardiac event, delivering an impedance
measurement pulse at a predetermined interval therefrom;
measuring impedance between the two electrodes using the delivered
impedance measurement pulse;
performing the first three [sic] steps repeatedly over a period
extending over multiple days to acquire a set of impedance data;
employing the set of impedance data to determine whether intra-
thoracic fluid content is increasing or decreasing; and
wherein the device comprises leads carrying the electrodes and
wherein the method further comprises employing the measured impedances
to assess the integrity of the leads.

The Examiner rejected the claims under 35 U.S.C. § 103(a) as
unpatentable over Combs et al. (US 5,957,861) and Schuelke et al. (US
5,755,742).

OBVIOUSNESS
Findings of Fact
1. Combs’ disclosure “relates to implantable devices including but not
limited to tissue stimulators having measurement capability for
determining impedance measurements and is particularly well suited
to measure long term edema variations within a living body.”
(Combs, col. 1, ll. 6-10.)
2. Combs disclosed that its system for determining edema included
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an implantable apparatus for production of impedance measurement in
a subcutaneous region of the living body having at least two
electrically isolated electrodes, preferably but not necessarily on the
outer surface of its housing and having within the housing an energy
pulse delivery mechanism to deliver electrical pulses to living body
and means for receiving electrical impulses on the surface of the
housing so as to determine the impedance of the body between the
two preferred or less preferred pair of electrodes.

(Id. at col. 3, ll. 16-25.)
3. Combs taught:
depending on the location of the electrodes used for measurement, it is
wise to consider synchronization to the heart beat cycle and the
respiratory cycles or the variation in measurement resulting from
measuring at inconsistent times within these cycles may cause
insurmountable difficulties in extracting useful signal from the
impedance changes created by these cycles.

(Id. at col. 6, ll. 51-57.)
4. Combs taught:
A chart or history of the impedance (LTA-STA) versus time could be
used to determine the effectiveness of drug therapy by including an
index circuit or memory circuit with comparative values in the device.
A determination of how severe the disease is by how quickly the
edema progresses (i.e. if the change was seen over the course of two
weeks, versus one day) becomes a measure that has value to the
patient and physician and can be a stored value kept in a memory
circuit by a device made in keeping with this invention.
With respect to configuration of the electrodes 50, preferred
embodiments include four electrodes with one common electrode,
three electrode’s, and two electrodes. (Reference to other potential
electrode configurations was described above at page 6) The
determination of pulmonary edema or local edema will be based upon
comparison of long term average impedance value compared to the
short term average value.

(Id. at col. 9, ll. 50-67.)
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5. Combs taught that “[l]ong term average preferably represents the
number of days (in the most preferred embodiment three to thirty)
while the short term average represents the number of hours
(preferably one to forty-eight).” (Id. at col. 10, ll. 14-18.)
6. Schuelke’s disclosure “relates to implantable pacemaker/cardioverter
defibrillators and more particularly to a method and apparatus for
measuring lead impedance and determining lead integrity employing
sub-threshold excitation pulses.” (Schuelke, col. 1, ll. 14-18.)
7. An object of Schuelke’s invention was “to provide such a PCD
[pacemaker/cardioverter/defibrillator] IPG [implantable
cardioverter/defibrillator] having a lead impedance measurement
feature for measuring the impedance of defibrillation leads using low
energy force pulses that are imperceptible to the patient.” (Id. at col.
4, ll. 29-34.)

The Issue
The Examiner found that Combs disclosed determining pulmonary or
local edema based on measuring impedance, and Combs’ method is the
same as Appellants’ method “except for assessing the integrity of the leads.”
(Final Rej. 3-4.) The Examiner found that Schuelke disclosed a lead
integrity measuring system measuring impedance values to determine lead
integrity failures, and concluded that it would have been obvious “to have
modified the system of Combs et al. to include a lead integrity measuring
system as taught by Schuelke et al. in order to provide the predictable results
of ensuring the leads are in proper working order. Furthermore, checking the
integrity of the leads would ensuring [sic] the sensed values are accurate.”
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(Id. at 4.) Finding that Schuelke disclosed a device with three leads, each
having an electrode, wherein the third electrode provided a cross-check of
measured impedance values, the Examiner concluded that Combs’ method,
modified with Schuelke’s system, would perform a cross-check of measured
impedance values with a third electrode. (Id. at 4-5.)
In their Appeal Brief, Appellants contend that the combined teachings
of Combs and Schuelke do not produce a device meeting the claims for three
reasons: (1) “Measurement during pacing pulses in Sch[ue]lke does not
teach measurement using the same mechanism as in Combs;” (2)
“Measurement during pacing pulses in Sch[ue]lke does not even teach
measurement at the same time as in Combs;” and (3) “Measurement during
pacing pulses as in Sch[ue]lke is irrelevant to the invention as claimed.”
(App. Br. 16-19.) According to Appellants, “The Examiner's proposed
combination is also clearly contrary to the express teaching of the references
and does not produce the claimed invention even if implemented as
proposed by the Examiner.” (Id. at 19.)
The Examiner’s Answer repeats the rejection, concluding again that it
would have been obvious “to have modified the system of Combs et al. to
include a lead integrity measuring system as taught by Schuelke et al.”
(Ans. 5.) However, the Answer responds to Appellants’ arguments by
explaining that the combination of Combs and Schuelke “merely teaches
that it is known to use impedance data for: determining intra-thoracic fluid
content AND assessing lead integrity.” (Ans. 8.) The Answer states the
rejection did not propose physically incorporating Schuelke’s mechanisms
into Combs’ device.
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Appellants reply that the rejection “expressly require[d] incorporation
of the impedance measurement system (mechanisms) of Schuelke into
Combs,” and the Examiner’s Answer is advancing “a new way of combining
the references.” (Reply Br. 2.) The Reply Brief contends the rejection
should be reversed in any case. (Id. at 3-13.)

Discussion
Based on the portions of the Combs disclosure cited in the rejection
(FF 1-5), we agree with the Examiner that the difference between Combs’
method and the claimed method is that Combs did not describe employing
its measured impedances to assess the integrity of the leads. (See Ans. 4-5.)
We also agree with the Examiner’s finding that Schuelke would have
motivated a person of ordinary skill in the art to use impedance
measurements to check lead integrity in Combs’ device. (See id.)
The rejection’s theory of how a person of ordinary skill would have
gone about implementing that idea is not clear, because there are various
ways to understand the proposal to modify Combs’ system with Schuelke’s
system. The appealed claim defines a method, but the rejection proposed
modifying a system. The rejection appeared to propose a change to the
mechanisms in Combs’ system, but the Answer states that was not intended.
Adding a data processing step to Combs’ method might have been the
intention, but the rejection did not say that. We conclude that the rejection’s
proposal to resolve the differences (“obvious . . . to have modified the
system of Combs et al. to include a lead integrity measuring system as
taught by Schuelke et al.”) is too terse to state a prima facie case for
obviousness. The underlying necessary reasoning is absent. “Rejections on
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obviousness grounds cannot be sustained by mere conclusory statements;
instead, there must be some articulated reasoning with some rational
underpinning to support the legal conclusion of obviousness.” In re Kahn,
441 F.3d 977, 988 (Fed. Cir. 2006), cited with approval in KSR Int’l Co. v.
Teleflex Inc., 550 U.S. 398, 417-18 (2007).

SUMMARY
We reverse the rejection of claims 80-82, 84-87, and 96-103 under
35 U.S.C. § 103(a) as unpatentable over Combs and Schuelke.

REVERSED

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