1037-00005 · Solstice Biomedical Devices Ltd · Prosecution Documents/CON-2

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PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT

CLAIM AMENDMENT COMPARISON CHART

U.S. Application No. 17/851,216 (SBD-001-CON2)

"Cryoablation Catheter with Integrated Impedance Mapping Electrodes"

PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT. This document has been prepared by counsel at Calderwood & Harkness LLP for the exclusive use of Solstice Biomedical Devices Ltd. in connection with the above-referenced patent prosecution matter. This document is not intended for filing with the United States Patent and Trademark Office without express client authorization. Distribution, reproduction, or disclosure of this document or any portion thereof to any third party is strictly prohibited without the prior written consent of Calderwood & Harkness LLP and Solstice Biomedical Devices Ltd.

I. INSTRUCTIONS AND LEGEND

This Claim Amendment Comparison Chart has been prepared as an internal working exhibit to accompany the draft Response to Non-Final Office Action in U.S. Application No. 17/851,216. The chart is intended to facilitate review by the prosecution team, outside technical advisors, and client representatives prior to finalization and filing of the formal amendment with the United States Patent and Trademark Office ("USPTO").

Formatting Conventions. The following conventions are used throughout this chart to identify changes between the original (currently pending) claim language and the proposed amended claim language:

• Additions to claim language are shown in underlined text. Underlined text represents new language proposed for insertion into the claims.

• Deletions from claim language are shown in ~~strikethrough~~ text. Strikethrough text represents language proposed for removal from the claims.

• Unchanged Language is shown in normal typeface without any special formatting. Normal text represents language that will remain as currently pending and is carried forward without modification.

Column Descriptions. The comparison table is organized into four columns, as follows:

• Column 1 — Claim Number: Identifies the claim by number, dependency status (independent or dependent), and amendment category.

• Column 2 — Original Claim Language (As Filed / Currently Pending): Sets forth the full text of the claim as it currently appears in the application, reflecting the most recent claim set of record before the Examiner.

• Column 3 — Proposed Amended Claim Language: Sets forth the full text of the proposed amended claim, incorporating all additions (underlined) and deletions (strikethrough) relative to the original claim language.

• Column 4 — Basis for Amendment / Notes: Provides a brief annotation explaining the purpose and rationale for each change, including identification of the rejection or objection being addressed, the distinguishing features relative to cited prior art, and specification support for new limitations.

Office Action Under Response. This chart addresses the Non-Final Office Action mailed by the USPTO on September 15, 2024, in which Primary Examiner James R. Dougherty set forth rejections and objections to Claims 1–20 as summarized in Section II below.

Cited Prior Art References. The following prior art references were cited in the Non-Final Office Action and are referenced throughout this chart:

1. U.S. Patent No. 10,537,418 ("the '418 patent") — Vantage Cryosurgical Systems, Inc. — Directed to a single-zone cryoablation balloon catheter system.

2. U.S. Patent No. 9,861,432 ("the '432 patent") — Vantage Cryosurgical Systems, Inc. — Directed to a cryoablation catheter with single-zone cooling and without impedance feedback functionality.

3. U.S. Published Application No. 2019/0183567 ("the '567 publication") — Helios Surgical Technologies, Inc. — Directed to a general cryoablation method and system, without zone-specific electrode integration or variable-zone cooling architecture.

Parent Specification. All amendments are supported by the specification as originally filed, which is identical in all material respects to the disclosure of U.S. Patent No. 11,284,561, issued March 22, 2022, from parent application U.S. Application No. 16/914,337. Column and line references to the parent specification throughout this chart refer to the issued patent text of U.S. Patent No. 11,284,561.

II. SUMMARY OF REJECTIONS AND AMENDMENT STRATEGY

A. Summary of Office Action Rejections and Objections

The Non-Final Office Action mailed September 15, 2024 sets forth the following rejections and objections:

B. Amendment Strategy Overview

The proposed amendments are designed to address each category of rejection and objection identified above while preserving the broadest commercially meaningful claim scope for Solstice Biomedical Devices Ltd. The strategy for each group of claims is summarized below.

Claims 1–8 (§ 103 Obviousness Rejection). Independent Claim 1 is amended to incorporate the variable-zone cooling architecture with integrated, zone-specific impedance mapping electrode limitations that are central to the inventive contribution of the application. Specifically, the amendments add: (a) a plurality of independently controllable cooling zones arranged along the longitudinal axis of the cryoablation element, each receiving a separately regulated flow of cryogenic fluid; (b) placement of at least one impedance mapping electrode within each cooling zone, configured for real-time local tissue impedance measurement during cryoablation; and (c) closed-loop control by the control unit, which independently adjusts cryogenic fluid flow to each cooling zone based on the impedance data from the electrode(s) within that zone. These limitations are not disclosed, individually or in combination, in any of the three cited prior art references. The Vantage '418 patent describes only a single-zone balloon catheter. The Vantage '432 patent describes a single-zone catheter without impedance feedback. The Helios '567 publication describes a general cryoablation system without zone-specific electrode integration or variable-zone cooling. Dependent Claims 2–8 are conformed to the multi-zone framework of amended Claim 1 by narrowing their respective limitations to reference the independently controllable cooling zones.

Claims 9–14 (§ 112(a) Written Description Rejection). Independent Claim 9 is amended to add explicit algorithmic detail for the impedance mapping calibration process, including: (a) bipolar and unipolar impedance measurement acquisition; (b) baseline impedance offset calculation using a comparison to a predetermined reference impedance value stored in a calibration table; (c) application of a temperature-compensation factor derived from a co-located temperature sensor; and (d) generation of calibrated impedance values by subtracting the offset and applying the compensation factor. These steps are fully disclosed in the parent specification at U.S. Patent No. 11,284,561, col. 9, ll. 25–67; col. 10, ll. 1–45; col. 11, ll. 10–55; and Figs. 6A–6C. The amendments also integrate the multi-zone catheter architecture and add anatomical positioning detail (pulmonary vein ostia) to further distinguish over the cited prior art. Dependent Claims 10–14 are conformed and narrowed to provide additional specificity regarding the calibration algorithm and measurement parameters.

Claims 15–20 (Objected-To Group — Allowable Subject Matter). Claim 15 is rewritten in independent form pursuant to the Examiner's indication under MPEP § 707.07(j) that it contains allowable subject matter. The rewritten Claim 15 incorporates all limitations of amended Claim 1 together with the automatic, zone-independent termination of cryogenic fluid delivery upon detection of a predetermined impedance threshold indicative of transmural lesion formation, while continuing delivery to remaining zones that have not reached the threshold. Dependent Claims 16–20 are conformed to the independent form of amended Claim 15 and narrowed for consistency with the multi-zone framework.

III. CLAIM AMENDMENT COMPARISON TABLE

A. Claims 1–8 (§ 103 Rejection Group)

Claim 1 (Independent — Substantive Amendment). Original Claim 1 (Currently Pending):

1\. A cryoablation catheter system comprising:

an elongate catheter body having a proximal end and a distal end;

a cryoablation element disposed at the distal end configured to deliver cryogenic fluid to target tissue;

a plurality of impedance mapping electrodes disposed along the cryoablation element; and

a control unit in communication with the cryoablation element and the plurality of impedance mapping electrodes.

Proposed Amended Claim 1:

1\. A cryoablation catheter system comprising:

an elongate catheter body having a proximal end and a distal end;

a cryoablation element disposed at the distal end, ~~configured to deliver cryogenic fluid to target tissue~~ the cryoablation element defining a plurality of independently controllable cooling zones arranged along a longitudinal axis of the cryoablation element, each cooling zone configured to receive a separately regulated flow of cryogenic fluid to deliver variable-zone cooling to target cardiac tissue;

a plurality of impedance mapping electrodes disposed along the cryoablation element, wherein at least one impedance mapping electrode is positioned within each of the plurality of independently controllable cooling zones and is configured to measure local tissue impedance in real time during cryoablation; and

a control unit in communication with the cryoablation element and the plurality of impedance mapping electrodes, the control unit configured to independently adjust cryogenic fluid flow to each cooling zone based on the local tissue impedance measured by the at least one impedance mapping electrode positioned within that cooling zone.

Basis for Amendment / Notes:

Amended to overcome the § 103 rejection over U.S. Pat. No. 10,537,418 in view of U.S. Pat. No. 9,861,432 and U.S. Pub. No. 2019/0183567. The amendments add the following distinguishing limitations: (1) "a plurality of independently controllable cooling zones" with "separately regulated flow" of cryogenic fluid (i.e., variable-zone cooling architecture); (2) placement of at least one impedance mapping electrode "within each" cooling zone, configured for "real-time" local tissue impedance measurement during cryoablation; and (3) closed-loop control whereby the control unit "independently adjust[s] cryogenic fluid flow to each cooling zone based on the local tissue impedance measured by the at least one impedance mapping electrode positioned within that cooling zone."

None of these limitations, individually or in combination, are disclosed in the cited prior art. The '418 patent (Vantage) describes only a single-zone balloon catheter without independently controllable cooling zones or zone-specific impedance feedback. The '432 patent (Vantage) describes a single-zone catheter without impedance feedback of any kind. The '567 publication (Helios) describes general cryoablation without zone-specific electrode integration, variable-zone cooling, or closed-loop impedance-based flow control.

Specification Support: U.S. Patent No. 11,284,561, col. 5, ll. 15–45 (describing multi-zone cryoablation element architecture); col. 8, ll. 1–30 (describing per-zone impedance electrode placement and real-time measurement); col. 12, ll. 10–40 (describing closed-loop, zone-specific cryogenic fluid flow control based on impedance data).

Claim 2 (Dependent on Claim 1 — Conforming Amendment). Original Claim 2 (Currently Pending):

2\. The system of claim 1, wherein the cryoablation element comprises a balloon.

Proposed Amended Claim 2:

2\. The system of claim 1, wherein the cryoablation element comprises a compliant balloon having internal partitions defining the plurality of independently controllable cooling zones.

Basis for Amendment / Notes:

Narrowed to specify that the balloon is a "compliant balloon" having "internal partitions" that define the plurality of independently controllable cooling zones recited in amended Claim 1. This conforming amendment distinguishes over the unpartitioned, single-zone balloon design disclosed in the Vantage '418 patent, which lacks any internal partitioning structure and operates as a monolithic cryoablation chamber.

Specification Support: U.S. Patent No. 11,284,561, col. 6, ll. 10–30 (describing compliant balloon construction with internal partition walls separating independently controllable cooling zones).

Claim 3 (Dependent on Claim 1 — Conforming Amendment). Original Claim 3 (Currently Pending):

3\. The system of claim 1, wherein the cryogenic fluid is nitrous oxide.

Proposed Amended Claim 3:

3\. The system of claim 1, wherein the cryogenic fluid delivered to each of the plurality of independently controllable cooling zones is nitrous oxide supplied through dedicated lumens within the catheter body.

Basis for Amendment / Notes:

Amended to tie the identification of nitrous oxide as the cryogenic fluid to the multi-zone delivery architecture, specifying that nitrous oxide is supplied to each independently controllable cooling zone "through dedicated lumens within the catheter body." This limitation distinguishes over the single-lumen cryogenic fluid delivery architectures described in the cited prior art, which utilize a single supply lumen to deliver cryogenic fluid to a monolithic ablation chamber.

Specification Support: U.S. Patent No. 11,284,561, col. 6, ll. 35–50 (describing multi-lumen catheter body construction with dedicated nitrous oxide supply lumens routed to each individual cooling zone).

Claim 4 (Dependent on Claim 1 — Conforming Amendment). Original Claim 4 (Currently Pending):

4\. The system of claim 1, wherein the plurality of impedance mapping electrodes comprises at least four electrodes.

Proposed Amended Claim 4:

4\. The system of claim 1, wherein the plurality of impedance mapping electrodes comprises at least four electrodes, with at least two electrodes positioned in each of at least two of the independently controllable cooling zones.

Basis for Amendment / Notes:

Amended to tie the minimum electrode count to a per-zone distribution requirement, specifying that at least two electrodes are positioned within each of at least two independently controllable cooling zones. This strengthens the distinction over the cited prior art, which does not disclose zone-specific electrode arrays or any distribution of impedance mapping electrodes across separately controllable cooling regions.

Specification Support: U.S. Patent No. 11,284,561, col. 8, ll. 15–30 (describing electrode distribution across multiple cooling zones with a minimum of two electrodes per zone for bipolar impedance measurement capability).

Claim 5 (Dependent on Claim 1 — Conforming Amendment). Original Claim 5 (Currently Pending):

5\. The system of claim 1, wherein the impedance mapping electrodes are ring electrodes.

Proposed Amended Claim 5:

5\. The system of claim 1, wherein the impedance mapping electrodes are ring electrodes circumferentially disposed on an outer surface of the cryoablation element within each of the plurality of independently controllable cooling zones.

Basis for Amendment / Notes:

Amended to add positional specificity for the ring electrode configuration, specifying that the ring electrodes are "circumferentially disposed on an outer surface of the cryoablation element" and are located "within each" of the independently controllable cooling zones. This structural limitation is not found in any of the cited prior art references.

Specification Support: U.S. Patent No. 11,284,561, col. 8, ll. 35–50 (describing ring electrode geometry and circumferential placement on the outer balloon surface within each cooling zone).

Claim 6 (Dependent on Claim 1 — Conforming Amendment). Original Claim 6 (Currently Pending):

6\. The system of claim 1, further comprising a temperature sensor disposed at the distal end of the catheter body.

Proposed Amended Claim 6:

6\. The system of claim 1, further comprising at least one temperature sensor disposed within each of the plurality of independently controllable cooling zones at the distal end of the catheter body.

Basis for Amendment / Notes:

Conformed to the multi-zone framework of amended Claim 1 by specifying that at least one temperature sensor is disposed "within each" of the independently controllable cooling zones, rather than merely "at the distal end" of the catheter body. Per-zone temperature sensing is not disclosed in the Vantage prior art or the Helios publication.

Specification Support: U.S. Patent No. 11,284,561, col. 9, ll. 1–15 (describing thermocouple or thermistor placement within each cooling zone for independent temperature monitoring).

Claim 7 (Dependent on Claim 1 — Conforming Amendment). Original Claim 7 (Currently Pending):

7\. The system of claim 1, wherein the control unit is configured to display a tissue impedance map.

Proposed Amended Claim 7:

7\. The system of claim 1, wherein the control unit is configured to generate and display a real-time tissue impedance map corresponding to each of the plurality of independently controllable cooling zones during cryoablation.

Basis for Amendment / Notes:

Amended to specify that the control unit both "generate[s] and display[s]" a "real-time" tissue impedance map and that the map corresponds to "each" of the independently controllable cooling zones during active cryoablation. Zone-specific impedance mapping display functionality is not taught or suggested in any of the three cited prior art references.

Specification Support: U.S. Patent No. 11,284,561, col. 13, ll. 1–20 (describing real-time generation and display of zone-specific impedance maps on the control unit display during cryoablation procedures).

Claim 8 (Dependent on Claim 7 — Conforming Amendment). Original Claim 8 (Currently Pending):

8\. The system of claim 7, wherein the tissue impedance map is updated in real time.

Proposed Amended Claim 8:

8\. The system of claim 7, wherein the tissue impedance map is updated in real time at a refresh rate of at least once per second based on impedance measurements from the plurality of impedance mapping electrodes positioned within each of the independently controllable cooling zones.

Basis for Amendment / Notes:

Amended to specify a minimum refresh rate of at least once per second and to identify the per-zone impedance mapping electrodes as the data source for the real-time updates. This quantitative specificity and per-zone data sourcing distinguishes over the cited prior art, which does not disclose refresh rate parameters or zone-specific impedance data acquisition for display purposes.

Specification Support: U.S. Patent No. 11,284,561, col. 14, ll. 5–20 (describing impedance map display refresh rates of approximately one to five updates per second, with data drawn from per-zone electrode arrays).

B. Claims 9–14 (§ 112(a) Rejection Group)

Claim 9 (Independent — Substantive Amendment). Original Claim 9 (Currently Pending):

9\. A method of calibrating an impedance mapping system for a cryoablation catheter, comprising:

positioning a cryoablation catheter having a plurality of impedance mapping electrodes within a cardiac chamber;

acquiring baseline impedance measurements from the plurality of impedance mapping electrodes;

applying a calibration algorithm to the baseline impedance measurements to generate calibrated impedance values; and

displaying the calibrated impedance values as a tissue contact map.

Proposed Amended Claim 9:

9\. A method of calibrating an impedance mapping system integrated with a multi-zone cryoablation catheter, ~~for a cryoablation catheter,~~ comprising:

positioning a cryoablation catheter having a plurality of independently controllable cooling zones and a plurality of impedance mapping electrodes, wherein at least one impedance mapping electrode is positioned within each cooling zone, within a cardiac chamber adjacent to pulmonary vein ostia;

acquiring baseline impedance measurements from each of the plurality of impedance mapping electrodes prior to delivery of cryogenic fluid, the baseline impedance measurements including a bipolar impedance measurement between adjacent electrodes and a unipolar impedance measurement between each electrode and a reference electrode;

applying a calibration algorithm to the baseline impedance measurements, the calibration algorithm comprising:

(a) calculating a baseline impedance offset for each electrode based on a comparison of the unipolar impedance measurement to a predetermined reference impedance value stored in a calibration table within a control unit;

(b) applying a temperature-compensation factor derived from a temperature sensor co-located with each impedance mapping electrode to normalize the baseline impedance measurements to a standard temperature; and

(c) generating calibrated impedance values for each electrode by subtracting the baseline impedance offset and applying the temperature-compensation factor; and

displaying the calibrated impedance values as a zone-specific tissue contact map indicating tissue contact quality at each of the plurality of independently controllable cooling zones.

Basis for Amendment / Notes:

Amended to overcome the § 112(a) written description rejection. The Examiner found that the originally claimed "calibration algorithm" lacked sufficient written description support because the specification did not adequately describe the algorithm with enough specificity for a person of ordinary skill in the art to recognize that the inventor had possession of the claimed invention at the time of filing.

The amendments add explicit algorithmic detail organized into three enumerated sub-steps: (a) calculating a baseline impedance offset for each electrode based on a comparison of the unipolar impedance measurement to a predetermined reference impedance value stored in a calibration table within the control unit; (b) applying a temperature-compensation factor derived from a co-located temperature sensor to normalize baseline impedance measurements to a standard temperature; and (c) generating calibrated impedance values by subtracting the baseline impedance offset and applying the temperature-compensation factor. The amendments also specify that the baseline impedance measurements include both bipolar impedance measurements (between adjacent electrodes) and unipolar impedance measurements (between each electrode and a reference electrode), which are acquired prior to delivery of cryogenic fluid.

Additionally, the amendments incorporate the multi-zone catheter architecture and pulmonary vein ostia anatomical positioning, providing further structural and functional context that distinguishes the claimed method over the cited prior art.

All amended limitations are fully supported in the parent specification. Specification Support: U.S. Patent No. 11,284,561, col. 9, ll. 25–67 (describing bipolar and unipolar impedance measurement acquisition protocols and pre-cryoablation baseline measurement procedures); col. 10, ll. 1–45 (describing calibration table structure, reference impedance values, and baseline offset calculation methodology); col. 11, ll. 10–55 (describing temperature-compensation factor derivation, normalization to standard temperature, and generation of calibrated impedance values by offset subtraction and factor application); Figs. 6A–6C (illustrating calibration algorithm flowchart, calibration table data structure, and temperature-compensation curve).

Claim 10 (Dependent on Claim 9 — Conforming Amendment). Original Claim 10 (Currently Pending):

10\. The method of claim 9, wherein the calibration algorithm accounts for temperature variations.

Proposed Amended Claim 10:

10\. The method of claim 9, wherein the temperature-compensation factor is derived from a linear regression model correlating measured tissue temperature at each cooling zone with impedance variation over a temperature range of approximately −80°C to 37°C.

Basis for Amendment / Notes:

Amended to add specificity to the temperature-compensation step by identifying the mathematical model (linear regression) and the operative temperature range (approximately −80°C to 37°C, spanning full cryoablation temperatures to normal body temperature). This amendment directly addresses the Examiner's § 112(a) concern by tying the temperature-compensation limitation to specific algorithmic detail disclosed in the parent specification.

Specification Support: U.S. Patent No. 11,284,561, col. 10, ll. 30–50 (describing linear regression model for temperature-impedance correlation across the cryoablation temperature range) and Fig. 6B (graphically illustrating the linear regression model and data points across the −80°C to 37°C range).

Claim 11 (Dependent on Claim 9 — Conforming Amendment). Original Claim 11 (Currently Pending):

11\. The method of claim 9, further comprising updating the calibrated impedance values during cryoablation.

Proposed Amended Claim 11:

11\. The method of claim 9, further comprising continuously updating the calibrated impedance values during cryoablation by repeating steps (a) through (c) of the calibration algorithm at intervals of no greater than one second, using real-time impedance measurements from each electrode within each independently controllable cooling zone.

Basis for Amendment / Notes:

Amended to specify that the updating occurs continuously by iterative re-execution of calibration steps (a) through (c) at intervals of no greater than one second, using real-time impedance data from each electrode within each independently controllable cooling zone. This provides the specificity required to satisfy § 112(a) by explaining how the calibration values are maintained during an active cryoablation procedure.

Specification Support: U.S. Patent No. 11,284,561, col. 11, ll. 35–55 (describing continuous recalibration loop executing at sub-second intervals during cryoablation with per-zone, per-electrode impedance data input).

Claim 12 (Dependent on Claim 9 — Conforming Amendment). Original Claim 12 (Currently Pending):

12\. The method of claim 9, wherein the tissue contact map is a color-coded map.

Proposed Amended Claim 12:

12\. The method of claim 9, wherein the zone-specific tissue contact map is a color-coded map in which each independently controllable cooling zone is represented by a distinct color gradient indicating a range of calibrated impedance values from no tissue contact to full tissue contact.

Basis for Amendment / Notes:

Conformed to the zone-specific display framework by specifying that each independently controllable cooling zone is represented by a distinct color gradient spanning from no tissue contact to full tissue contact, based on the calibrated impedance values generated by the calibration algorithm of Claim 9.

Specification Support: U.S. Patent No. 11,284,561, col. 13, ll. 5–25 (describing zone-specific color-coded tissue contact map display with graduated color scales) and Fig. 8 (illustrating exemplary zone-specific color-coded tissue contact map).

Claim 13 (Dependent on Claim 9 — Conforming Amendment). Original Claim 13 (Currently Pending):

13\. The method of claim 9, wherein the baseline impedance measurements are acquired over a period of at least five seconds.

Proposed Amended Claim 13:

13\. The method of claim 9, wherein the baseline impedance measurements are acquired by sampling each of the bipolar impedance measurement and the unipolar impedance measurement over a period of at least five seconds at a sampling rate of at least 100 Hz prior to delivery of cryogenic fluid.

Basis for Amendment / Notes:

Amended to specify the sampling rate (at least 100 Hz) and to confirm that both the bipolar and unipolar impedance measurement types are sampled during the baseline acquisition period, prior to delivery of cryogenic fluid. This additional detail further addresses the Examiner's § 112(a) concerns by demonstrating that the specification provides sufficient written description of the data acquisition parameters underlying the calibration algorithm.

Specification Support: U.S. Patent No. 11,284,561, col. 9, ll. 45–60 (describing baseline impedance data acquisition at sampling rates of 100 Hz to 1 kHz over a minimum five-second pre-ablation window, with simultaneous bipolar and unipolar measurement channels).

Claim 14 (Dependent on Claim 9 — Conforming Amendment). Original Claim 14 (Currently Pending):

14\. The method of claim 9, wherein the cardiac chamber is a left atrium.

Proposed Amended Claim 14:

14\. The method of claim 9, wherein the cardiac chamber is a left atrium and the cryoablation catheter is positioned such that at least two of the plurality of independently controllable cooling zones are in contact with tissue surrounding a pulmonary vein ostium.

Basis for Amendment / Notes:

Amended to add anatomical and positional specificity relevant to the primary clinical application of pulmonary vein isolation for the treatment of atrial fibrillation. The amendment specifies that at least two of the independently controllable cooling zones are in contact with tissue surrounding a pulmonary vein ostium, reflecting the intended multi-zone engagement with target anatomy during the calibration and subsequent ablation procedure.

Specification Support: U.S. Patent No. 11,284,561, col. 7, ll. 10–30 (describing catheter deployment and positioning within the left atrium for pulmonary vein isolation, including multi-zone contact with peristial tissue).

C. Claims 15–20 (Objected-To Group — Rewritten in Independent Form)

Claim 15 (Rewritten as Independent — Substantive Amendment). Original Claim 15 (Currently Pending):

15\. The system of claim 1, wherein the control unit is configured to automatically terminate cryogenic fluid delivery to a cooling zone upon detecting a predetermined impedance threshold indicative of transmural lesion formation at that cooling zone.

Proposed Amended Claim 15 (Rewritten in Independent Form):

15\. A cryoablation catheter system comprising:

an elongate catheter body having a proximal end and a distal end;

a cryoablation element disposed at the distal end, the cryoablation element defining a plurality of independently controllable cooling zones arranged along a longitudinal axis of the cryoablation element, each cooling zone configured to receive a separately regulated flow of cryogenic fluid to deliver variable-zone cooling to target cardiac tissue;

a plurality of impedance mapping electrodes disposed along the cryoablation element, wherein at least one impedance mapping electrode is positioned within each of the plurality of independently controllable cooling zones and is configured to measure local tissue impedance in real time during cryoablation; and

a control unit in communication with the cryoablation element and the plurality of impedance mapping electrodes, the control unit configured to:

(i) independently adjust cryogenic fluid flow to each cooling zone based on the local tissue impedance measured by the at least one impedance mapping electrode positioned within that cooling zone; and

(ii) automatically terminate cryogenic fluid delivery to an individual cooling zone of the plurality of independently controllable cooling zones upon detecting that the local tissue impedance measured by the at least one impedance mapping electrode within that individual cooling zone has reached a predetermined impedance threshold indicative of transmural lesion formation at that cooling zone, while continuing cryogenic fluid delivery to remaining cooling zones that have not reached the predetermined impedance threshold.

Basis for Amendment / Notes:

Rewritten in independent form pursuant to the Examiner's indication under MPEP § 707.07(j) that Claim 15 contains allowable subject matter. The rewritten independent Claim 15 incorporates all limitations of amended Claim 1 (the multi-zone cryoablation element, per-zone impedance electrodes with real-time measurement, and closed-loop zone-specific cryogenic fluid flow control) together with the automatic termination feature that was the subject of the Examiner's allowability indication. Critically, the rewritten claim specifies that the control unit automatically terminates cryogenic fluid delivery to an "individual cooling zone" upon detection of the predetermined impedance threshold, "while continuing cryogenic fluid delivery to remaining cooling zones that have not reached the predetermined impedance threshold." This zone-independent termination functionality — allowing selective cessation of cryoablation at zones where transmural lesion formation is confirmed while maintaining ablation at zones where treatment is still ongoing — represents the core distinguishing feature acknowledged by the Examiner as not taught or suggested by the cited prior art.

Specification Support: U.S. Patent No. 11,284,561, col. 15, ll. 1–35 (describing zone-independent automatic termination logic based on impedance threshold detection for transmural lesion confirmation); col. 16, ll. 5–30 (describing control unit architecture for simultaneous per-zone monitoring and selective termination/continuation of cryogenic fluid delivery); Fig. 9 (illustrating control flow diagram for automatic zone-specific termination with continued delivery to non-threshold zones).

Claim 16 (Dependent on Claim 15 — Conforming Amendment). Original Claim 16 (Currently Pending):

16\. The system of claim 15, wherein the predetermined impedance threshold is adjustable by a user.

Proposed Amended Claim 16:

16\. The system of claim 15, wherein the predetermined impedance threshold is adjustable by a user via a graphical interface on the control unit, and different predetermined impedance thresholds may be set for different cooling zones.

Basis for Amendment / Notes:

Conformed to the multi-zone framework of rewritten independent Claim 15 by specifying that the user may set different predetermined impedance thresholds for different cooling zones via a graphical user interface on the control unit. This per-zone threshold customization enables clinicians to tailor termination criteria based on the varying tissue characteristics and anatomical positions of each cooling zone.

Specification Support: U.S. Patent No. 11,284,561, col. 16, ll. 15–30 (describing graphical user interface for per-zone impedance threshold adjustment by the operator).

Claim 17 (Dependent on Claim 15 — Conforming Amendment). Original Claim 17 (Currently Pending):

17\. The system of claim 15, wherein the predetermined impedance threshold corresponds to an impedance drop of at least 15% from a baseline impedance value.

Proposed Amended Claim 17:

17\. The system of claim 15, wherein the predetermined impedance threshold for each cooling zone corresponds to an impedance drop of at least 15% from a baseline impedance value measured by the at least one impedance mapping electrode within that cooling zone prior to cryogenic fluid delivery.

Basis for Amendment / Notes:

Amended to tie the 15% impedance drop threshold to a per-zone baseline measurement acquired by the zone-specific impedance mapping electrode prior to cryogenic fluid delivery. This ensures that the threshold for transmural lesion detection is calibrated on a per-zone basis against the actual pre-ablation tissue impedance characteristics at each individual cooling zone location.

Specification Support: U.S. Patent No. 11,284,561, col. 15, ll. 20–35 (describing per-zone baseline impedance acquisition and percentage-based threshold calculation for transmural lesion detection).

Claim 18 (Dependent on Claim 15 — Conforming Amendment). Original Claim 18 (Currently Pending):

18\. The system of claim 15, wherein the control unit generates an alert upon terminating cryogenic fluid delivery.

Proposed Amended Claim 18:

18\. The system of claim 15, wherein the control unit generates a zone-specific visual and audible alert upon automatically terminating cryogenic fluid delivery to the individual cooling zone, the alert identifying which of the plurality of cooling zones has reached the predetermined impedance threshold.

Basis for Amendment / Notes:

Amended to specify that the alert is zone-specific, includes both visual and audible components, and identifies which particular cooling zone has reached the predetermined impedance threshold and triggered automatic termination. This provides the clinician with actionable, zone-level feedback during the procedure.

Specification Support: U.S. Patent No. 11,284,561, col. 16, ll. 25–45 (describing zone-specific visual indicators on the control unit display and audible alert tones triggered upon automatic cryogenic fluid termination at individual cooling zones).

Claim 19 (Dependent on Claim 15 — Conforming Amendment). Original Claim 19 (Currently Pending):

19\. The system of claim 15, further comprising a data logging module configured to record impedance measurements and cryoablation parameters over time.

Proposed Amended Claim 19:

19\. The system of claim 15, further comprising a data logging module within the control unit configured to record, for each of the plurality of independently controllable cooling zones, impedance measurements from the at least one impedance mapping electrode, cryogenic fluid flow rates, temperature readings, and timestamps of automatic cryogenic fluid termination events ~~cryoablation parameters over time~~.

Basis for Amendment / Notes:

Amended to add per-zone granularity to the data logging functionality and to enumerate specific parameters recorded by the data logging module: (1) impedance measurements from the zone-specific impedance mapping electrodes; (2) cryogenic fluid flow rates to each zone; (3) temperature readings at each zone; and (4) timestamps of automatic cryogenic fluid termination events for each zone. The data logging module is also specified as being located "within the control unit."

Specification Support: U.S. Patent No. 11,284,561, col. 17, ll. 5–25 (describing integrated data logging module within the control unit that records per-zone impedance, flow rate, temperature, and event timestamp data for post-procedure analysis and regulatory documentation).

Claim 20 (Dependent on Claim 15 — Conforming Amendment). Original Claim 20 (Currently Pending):

20\. The system of claim 15, wherein the cryoablation element is configured for pulmonary vein isolation in treatment of atrial fibrillation.

Proposed Amended Claim 20:

20\. The system of claim 15, wherein the cryoablation element is configured for pulmonary vein isolation in treatment of atrial fibrillation, and wherein the plurality of independently controllable cooling zones are dimensioned and arranged to simultaneously contact tissue circumferentially surrounding a pulmonary vein ostium such that each cooling zone treats a different circumferential segment of the pulmonary vein ostium.

Basis for Amendment / Notes:

PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT
CLAIM AMENDMENT COMPARISON CHART
U.S. Application No. 17/851,216 (SBD-001-CON2)
"Cryoablation Catheter with Integrated Impedance Mapping Electrodes"
PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT. This document has been prepared by counsel at Calderwood & Harkness LLP for the exclusive use of Solstice Biomedical Devices Ltd. in connection with the above-referenced patent prosecution matter. This document is not intended for filing with the United States Patent and Trademark Office without express client authorization. Distribution, reproduction, or disclosure of this document or any portion thereof to any third party is strictly prohibited without the prior written consent of Calderwood & Harkness LLP and Solstice Biomedical Devices Ltd.
I. INSTRUCTIONS AND LEGEND
This Claim Amendment Comparison Chart has been prepared as an internal working exhibit to accompany the draft Response to Non-Final Office Action in U.S. Application No. 17/851,216. The chart is intended to facilitate review by the prosecution team, outside technical advisors, and client representatives prior to finalization and filing of the formal amendment with the United States Patent and Trademark Office ("USPTO").
Formatting Conventions. The following conventions are used throughout this chart to identify changes between the original (currently pending) claim language and the proposed amended claim language:
•  Additions to claim language are shown in underlined text. Underlined text represents new language proposed for insertion into the claims.
•  Deletions from claim language are shown in ~~strikethrough~~ text. Strikethrough text represents language proposed for removal from the claims.
•  Unchanged Language is shown in normal typeface without any special formatting. Normal text represents language that will remain as currently pending and is carried forward without modification.
Column Descriptions. The comparison table is organized into four columns, as follows:
•  Column 1 — Claim Number: Identifies the claim by number, dependency status (independent or dependent), and amendment category.
•  Column 2 — Original Claim Language (As Filed / Currently Pending): Sets forth the full text of the claim as it currently appears in the application, reflecting the most recent claim set of record before the Examiner.
•  Column 3 — Proposed Amended Claim Language: Sets forth the full text of the proposed amended claim, incorporating all additions (underlined) and deletions (strikethrough) relative to the original claim language.
•  Column 4 — Basis for Amendment / Notes: Provides a brief annotation explaining the purpose and rationale for each change, including identification of the rejection or objection being addressed, the distinguishing features relative to cited prior art, and specification support for new limitations.
Office Action Under Response. This chart addresses the Non-Final Office Action mailed by the USPTO on September 15, 2024, in which Primary Examiner James R. Dougherty set forth rejections and objections to Claims 1–20 as summarized in Section II below.
Cited Prior Art References. The following prior art references were cited in the Non-Final Office Action and are referenced throughout this chart:
1.  U.S. Patent No. 10,537,418 ("the '418 patent") — Vantage Cryosurgical Systems, Inc. — Directed to a single-zone cryoablation balloon catheter system.
2.  U.S. Patent No. 9,861,432 ("the '432 patent") — Vantage Cryosurgical Systems, Inc. — Directed to a cryoablation catheter with single-zone cooling and without impedance feedback functionality.
3.  U.S. Published Application No. 2019/0183567 ("the '567 publication") — Helios Surgical Technologies, Inc. — Directed to a general cryoablation method and system, without zone-specific electrode integration or variable-zone cooling architecture.
Parent Specification. All amendments are supported by the specification as originally filed, which is identical in all material respects to the disclosure of U.S. Patent No. 11,284,561, issued March 22, 2022, from parent application U.S. Application No. 16/914,337. Column and line references to the parent specification throughout this chart refer to the issued patent text of U.S. Patent No. 11,284,561.
II. SUMMARY OF REJECTIONS AND AMENDMENT STRATEGY
A. Summary of Office Action Rejections and Objections
The Non-Final Office Action mailed September 15, 2024 sets forth the following rejections and objections:
B. Amendment Strategy Overview
The proposed amendments are designed to address each category of rejection and objection identified above while preserving the broadest commercially meaningful claim scope for Solstice Biomedical Devices Ltd. The strategy for each group of claims is summarized below.
Claims 1–8 (§ 103 Obviousness Rejection). Independent Claim 1 is amended to incorporate the variable-zone cooling architecture with integrated, zone-specific impedance mapping electrode limitations that are central to the inventive contribution of the application. Specifically, the amendments add: (a) a plurality of independently controllable cooling zones arranged along the longitudinal axis of the cryoablation element, each receiving a separately regulated flow of cryogenic fluid; (b) placement of at least one impedance mapping electrode within each cooling zone, configured for real-time local tissue impedance measurement during cryoablation; and (c) closed-loop control by the control unit, which independently adjusts cryogenic fluid flow to each cooling zone based on the impedance data from the electrode(s) within that zone. These limitations are not disclosed, individually or in combination, in any of the three cited prior art references. The Vantage '418 patent describes only a single-zone balloon catheter. The Vantage '432 patent describes a single-zone catheter without impedance feedback. The Helios '567 publication describes a general cryoablation system without zone-specific electrode integration or variable-zone cooling. Dependent Claims 2–8 are conformed to the multi-zone framework of amended Claim 1 by narrowing their respective limitations to reference the independently controllable cooling zones.
Claims 9–14 (§ 112(a) Written Description Rejection). Independent Claim 9 is amended to add explicit algorithmic detail for the impedance mapping calibration process, including: (a) bipolar and unipolar impedance measurement acquisition; (b) baseline impedance offset calculation using a comparison to a predetermined reference impedance value stored in a calibration table; (c) application of a temperature-compensation factor derived from a co-located temperature sensor; and (d) generation of calibrated impedance values by subtracting the offset and applying the compensation factor. These steps are fully disclosed in the parent specification at U.S. Patent No. 11,284,561, col. 9, ll. 25–67; col. 10, ll. 1–45; col. 11, ll. 10–55; and Figs. 6A–6C. The amendments also integrate the multi-zone catheter architecture and add anatomical positioning detail (pulmonary vein ostia) to further distinguish over the cited prior art. Dependent Claims 10–14 are conformed and narrowed to provide additional specificity regarding the calibration algorithm and measurement parameters.
Claims 15–20 (Objected-To Group — Allowable Subject Matter). Claim 15 is rewritten in independent form pursuant to the Examiner's indication under MPEP § 707.07(j) that it contains allowable subject matter. The rewritten Claim 15 incorporates all limitations of amended Claim 1 together with the automatic, zone-independent termination of cryogenic fluid delivery upon detection of a predetermined impedance threshold indicative of transmural lesion formation, while continuing delivery to remaining zones that have not reached the threshold. Dependent Claims 16–20 are conformed to the independent form of amended Claim 15 and narrowed for consistency with the multi-zone framework.
III. CLAIM AMENDMENT COMPARISON TABLE
A. Claims 1–8 (§ 103 Rejection Group)
Claim 1 (Independent — Substantive Amendment).  Original Claim 1 (Currently Pending):
1\. A cryoablation catheter system comprising:
an elongate catheter body having a proximal end and a distal end;
a cryoablation element disposed at the distal end configured to deliver cryogenic fluid to target tissue;
a plurality of impedance mapping electrodes disposed along the cryoablation element; and
a control unit in communication with the cryoablation element and the plurality of impedance mapping electrodes.
Proposed Amended Claim 1:
1\. A cryoablation catheter system comprising:
an elongate catheter body having a proximal end and a distal end;
a cryoablation element disposed at the distal end, ~~configured to deliver cryogenic fluid to target tissue~~ <u>the cryoablation element defining a plurality of independently controllable cooling zones arranged along a longitudinal axis of the cryoablation element, each cooling zone configured to receive a separately regulated flow of cryogenic fluid to deliver variable-zone cooling to target cardiac tissue</u>;
a plurality of impedance mapping electrodes disposed along the cryoablation element, <u>wherein at least one impedance mapping electrode is positioned within each of the plurality of independently controllable cooling zones and is configured to measure local tissue impedance in real time during cryoablation</u>; and
a control unit in communication with the cryoablation element and the plurality of impedance mapping electrodes, <u>the control unit configured to independently adjust cryogenic fluid flow to each cooling zone based on the local tissue impedance measured by the at least one impedance mapping electrode positioned within that cooling zone</u>.
Basis for Amendment / Notes:
Amended to overcome the § 103 rejection over U.S. Pat. No. 10,537,418 in view of U.S. Pat. No. 9,861,432 and U.S. Pub. No. 2019/0183567. The amendments add the following distinguishing limitations: (1) "a plurality of independently controllable cooling zones" with "separately regulated flow" of cryogenic fluid (i.e., variable-zone cooling architecture); (2) placement of at least one impedance mapping electrode "within each" cooling zone, configured for "real-time" local tissue impedance measurement during cryoablation; and (3) closed-loop control whereby the control unit "independently adjust[s] cryogenic fluid flow to each cooling zone based on the local tissue impedance measured by the at least one impedance mapping electrode positioned within that cooling zone."
None of these limitations, individually or in combination, are disclosed in the cited prior art. The '418 patent (Vantage) describes only a single-zone balloon catheter without independently controllable cooling zones or zone-specific impedance feedback. The '432 patent (Vantage) describes a single-zone catheter without impedance feedback of any kind. The '567 publication (Helios) describes general cryoablation without zone-specific electrode integration, variable-zone cooling, or closed-loop impedance-based flow control.
Specification Support: U.S. Patent No. 11,284,561, col. 5, ll. 15–45 (describing multi-zone cryoablation element architecture); col. 8, ll. 1–30 (describing per-zone impedance electrode placement and real-time measurement); col. 12, ll. 10–40 (describing closed-loop, zone-specific cryogenic fluid flow control based on impedance data).
Claim 2 (Dependent on Claim 1 — Conforming Amendment).  Original Claim 2 (Currently Pending):
2\. The system of claim 1, wherein the cryoablation element comprises a balloon.
Proposed Amended Claim 2:
2\. The system of claim 1, wherein the cryoablation element comprises a <u>compliant</u> balloon <u>having internal partitions defining the plurality of independently controllable cooling zones</u>.
Basis for Amendment / Notes:
Narrowed to specify that the balloon is a "compliant balloon" having "internal partitions" that define the plurality of independently controllable cooling zones recited in amended Claim 1. This conforming amendment distinguishes over the unpartitioned, single-zone balloon design disclosed in the Vantage '418 patent, which lacks any internal partitioning structure and operates as a monolithic cryoablation chamber.
Specification Support: U.S. Patent No. 11,284,561, col. 6, ll. 10–30 (describing compliant balloon construction with internal partition walls separating independently controllable cooling zones).
Claim 3 (Dependent on Claim 1 — Conforming Amendment).  Original Claim 3 (Currently Pending):
3\. The system of claim 1, wherein the cryogenic fluid is nitrous oxide.
Proposed Amended Claim 3:
3\. The system of claim 1, wherein the cryogenic fluid <u>delivered to each of the plurality of independently controllable cooling zones</u> is nitrous oxide <u>supplied through dedicated lumens within the catheter body</u>.
Basis for Amendment / Notes:
Amended to tie the identification of nitrous oxide as the cryogenic fluid to the multi-zone delivery architecture, specifying that nitrous oxide is supplied to each independently controllable cooling zone "through dedicated lumens within the catheter body." This limitation distinguishes over the single-lumen cryogenic fluid delivery architectures described in the cited prior art, which utilize a single supply lumen to deliver cryogenic fluid to a monolithic ablation chamber.
Specification Support: U.S. Patent No. 11,284,561, col. 6, ll. 35–50 (describing multi-lumen catheter body construction with dedicated nitrous oxide supply lumens routed to each individual cooling zone).
Claim 4 (Dependent on Claim 1 — Conforming Amendment).  Original Claim 4 (Currently Pending):
4\. The system of claim 1, wherein the plurality of impedance mapping electrodes comprises at least four electrodes.
Proposed Amended Claim 4:
4\. The system of claim 1, wherein the plurality of impedance mapping electrodes comprises at least four electrodes, <u>with at least two electrodes positioned in each of at least two of the independently controllable cooling zones</u>.
Basis for Amendment / Notes:
Amended to tie the minimum electrode count to a per-zone distribution requirement, specifying that at least two electrodes are positioned within each of at least two independently controllable cooling zones. This strengthens the distinction over the cited prior art, which does not disclose zone-specific electrode arrays or any distribution of impedance mapping electrodes across separately controllable cooling regions.
Specification Support: U.S. Patent No. 11,284,561, col. 8, ll. 15–30 (describing electrode distribution across multiple cooling zones with a minimum of two electrodes per zone for bipolar impedance measurement capability).
Claim 5 (Dependent on Claim 1 — Conforming Amendment).  Original Claim 5 (Currently Pending):
5\. The system of claim 1, wherein the impedance mapping electrodes are ring electrodes.
Proposed Amended Claim 5:
5\. The system of claim 1, wherein the impedance mapping electrodes are ring electrodes <u>circumferentially disposed on an outer surface of the cryoablation element within each of the plurality of independently controllable cooling zones</u>.
Basis for Amendment / Notes:
Amended to add positional specificity for the ring electrode configuration, specifying that the ring electrodes are "circumferentially disposed on an outer surface of the cryoablation element" and are located "within each" of the independently controllable cooling zones. This structural limitation is not found in any of the cited prior art references.
Specification Support: U.S. Patent No. 11,284,561, col. 8, ll. 35–50 (describing ring electrode geometry and circumferential placement on the outer balloon surface within each cooling zone).
Claim 6 (Dependent on Claim 1 — Conforming Amendment).  Original Claim 6 (Currently Pending):
6\. The system of claim 1, further comprising a temperature sensor disposed at the distal end of the catheter body.
Proposed Amended Claim 6:
6\. The system of claim 1, further comprising <u>at least one</u> temperature sensor disposed <u>within each of the plurality of independently controllable cooling zones</u> at the distal end of the catheter body.
Basis for Amendment / Notes:
Conformed to the multi-zone framework of amended Claim 1 by specifying that at least one temperature sensor is disposed "within each" of the independently controllable cooling zones, rather than merely "at the distal end" of the catheter body. Per-zone temperature sensing is not disclosed in the Vantage prior art or the Helios publication.
Specification Support: U.S. Patent No. 11,284,561, col. 9, ll. 1–15 (describing thermocouple or thermistor placement within each cooling zone for independent temperature monitoring).
Claim 7 (Dependent on Claim 1 — Conforming Amendment).  Original Claim 7 (Currently Pending):
7\. The system of claim 1, wherein the control unit is configured to display a tissue impedance map.
Proposed Amended Claim 7:
7\. The system of claim 1, wherein the control unit is configured to <u>generate and</u> display a <u>real-time</u> tissue impedance map <u>corresponding to each of the plurality of independently controllable cooling zones during cryoablation</u>.
Basis for Amendment / Notes:
Amended to specify that the control unit both "generate[s] and display[s]" a "real-time" tissue impedance map and that the map corresponds to "each" of the independently controllable cooling zones during active cryoablation. Zone-specific impedance mapping display functionality is not taught or suggested in any of the three cited prior art references.
Specification Support: U.S. Patent No. 11,284,561, col. 13, ll. 1–20 (describing real-time generation and display of zone-specific impedance maps on the control unit display during cryoablation procedures).
Claim 8 (Dependent on Claim 7 — Conforming Amendment).  Original Claim 8 (Currently Pending):
8\. The system of claim 7, wherein the tissue impedance map is updated in real time.
Proposed Amended Claim 8:
8\. The system of claim 7, wherein the tissue impedance map is updated in real time <u>at a refresh rate of at least once per second based on impedance measurements from the plurality of impedance mapping electrodes positioned within each of the independently controllable cooling zones</u>.
Basis for Amendment / Notes:
Amended to specify a minimum refresh rate of at least once per second and to identify the per-zone impedance mapping electrodes as the data source for the real-time updates. This quantitative specificity and per-zone data sourcing distinguishes over the cited prior art, which does not disclose refresh rate parameters or zone-specific impedance data acquisition for display purposes.
Specification Support: U.S. Patent No. 11,284,561, col. 14, ll. 5–20 (describing impedance map display refresh rates of approximately one to five updates per second, with data drawn from per-zone electrode arrays).
B. Claims 9–14 (§ 112(a) Rejection Group)
Claim 9 (Independent — Substantive Amendment).  Original Claim 9 (Currently Pending):
9\. A method of calibrating an impedance mapping system for a cryoablation catheter, comprising:
positioning a cryoablation catheter having a plurality of impedance mapping electrodes within a cardiac chamber;
acquiring baseline impedance measurements from the plurality of impedance mapping electrodes;
applying a calibration algorithm to the baseline impedance measurements to generate calibrated impedance values; and
displaying the calibrated impedance values as a tissue contact map.
Proposed Amended Claim 9:
9\. A method of calibrating an impedance mapping system <u>integrated with a multi-zone cryoablation catheter</u>, ~~for a cryoablation catheter,~~ comprising:
positioning a cryoablation catheter having <u>a plurality of independently controllable cooling zones and</u> a plurality of impedance mapping electrodes, <u>wherein at least one impedance mapping electrode is positioned within each cooling zone,</u> within a cardiac chamber <u>adjacent to pulmonary vein ostia</u>;
acquiring baseline impedance measurements from <u>each of</u> the plurality of impedance mapping electrodes <u>prior to delivery of cryogenic fluid, the baseline impedance measurements including a bipolar impedance measurement between adjacent electrodes and a unipolar impedance measurement between each electrode and a reference electrode</u>;
applying a calibration algorithm to the baseline impedance measurements, <u>the calibration algorithm comprising:</u>
<u>(a) calculating a baseline impedance offset for each electrode based on a comparison of the unipolar impedance measurement to a predetermined reference impedance value stored in a calibration table within a control unit;</u>
<u>(b) applying a temperature-compensation factor derived from a temperature sensor co-located with each impedance mapping electrode to normalize the baseline impedance measurements to a standard temperature; and</u>
<u>(c) generating calibrated impedance values for each electrode by subtracting the baseline impedance offset and applying the temperature-compensation factor;</u> and
displaying the calibrated impedance values as a <u>zone-specific</u> tissue contact map <u>indicating tissue contact quality at each of the plurality of independently controllable cooling zones</u>.
Basis for Amendment / Notes:
Amended to overcome the § 112(a) written description rejection. The Examiner found that the originally claimed "calibration algorithm" lacked sufficient written description support because the specification did not adequately describe the algorithm with enough specificity for a person of ordinary skill in the art to recognize that the inventor had possession of the claimed invention at the time of filing.
The amendments add explicit algorithmic detail organized into three enumerated sub-steps: (a) calculating a baseline impedance offset for each electrode based on a comparison of the unipolar impedance measurement to a predetermined reference impedance value stored in a calibration table within the control unit; (b) applying a temperature-compensation factor derived from a co-located temperature sensor to normalize baseline impedance measurements to a standard temperature; and (c) generating calibrated impedance values by subtracting the baseline impedance offset and applying the temperature-compensation factor. The amendments also specify that the baseline impedance measurements include both bipolar impedance measurements (between adjacent electrodes) and unipolar impedance measurements (between each electrode and a reference electrode), which are acquired prior to delivery of cryogenic fluid.
Additionally, the amendments incorporate the multi-zone catheter architecture and pulmonary vein ostia anatomical positioning, providing further structural and functional context that distinguishes the claimed method over the cited prior art.
All amended limitations are fully supported in the parent specification. Specification Support: U.S. Patent No. 11,284,561, col. 9, ll. 25–67 (describing bipolar and unipolar impedance measurement acquisition protocols and pre-cryoablation baseline measurement procedures); col. 10, ll. 1–45 (describing calibration table structure, reference impedance values, and baseline offset calculation methodology); col. 11, ll. 10–55 (describing temperature-compensation factor derivation, normalization to standard temperature, and generation of calibrated impedance values by offset subtraction and factor application); Figs. 6A–6C (illustrating calibration algorithm flowchart, calibration table data structure, and temperature-compensation curve).
Claim 10 (Dependent on Claim 9 — Conforming Amendment).  Original Claim 10 (Currently Pending):
10\. The method of claim 9, wherein the calibration algorithm accounts for temperature variations.
Proposed Amended Claim 10:
10\. The method of claim 9, wherein the temperature-compensation factor is <u>derived from a linear regression model correlating measured tissue temperature at each cooling zone with impedance variation over a temperature range of approximately −80°C to 37°C</u>.
Basis for Amendment / Notes:
Amended to add specificity to the temperature-compensation step by identifying the mathematical model (linear regression) and the operative temperature range (approximately −80°C to 37°C, spanning full cryoablation temperatures to normal body temperature). This amendment directly addresses the Examiner's § 112(a) concern by tying the temperature-compensation limitation to specific algorithmic detail disclosed in the parent specification.
Specification Support: U.S. Patent No. 11,284,561, col. 10, ll. 30–50 (describing linear regression model for temperature-impedance correlation across the cryoablation temperature range) and Fig. 6B (graphically illustrating the linear regression model and data points across the −80°C to 37°C range).
Claim 11 (Dependent on Claim 9 — Conforming Amendment).  Original Claim 11 (Currently Pending):
11\. The method of claim 9, further comprising updating the calibrated impedance values during cryoablation.
Proposed Amended Claim 11:
11\. The method of claim 9, further comprising <u>continuously</u> updating the calibrated impedance values during cryoablation <u>by repeating steps (a) through (c) of the calibration algorithm at intervals of no greater than one second, using real-time impedance measurements from each electrode within each independently controllable cooling zone</u>.
Basis for Amendment / Notes:
Amended to specify that the updating occurs continuously by iterative re-execution of calibration steps (a) through (c) at intervals of no greater than one second, using real-time impedance data from each electrode within each independently controllable cooling zone. This provides the specificity required to satisfy § 112(a) by explaining how the calibration values are maintained during an active cryoablation procedure.
Specification Support: U.S. Patent No. 11,284,561, col. 11, ll. 35–55 (describing continuous recalibration loop executing at sub-second intervals during cryoablation with per-zone, per-electrode impedance data input).
Claim 12 (Dependent on Claim 9 — Conforming Amendment).  Original Claim 12 (Currently Pending):
12\. The method of claim 9, wherein the tissue contact map is a color-coded map.
Proposed Amended Claim 12:
12\. The method of claim 9, wherein the <u>zone-specific</u> tissue contact map is a color-coded map <u>in which each independently controllable cooling zone is represented by a distinct color gradient indicating a range of calibrated impedance values from no tissue contact to full tissue contact</u>.
Basis for Amendment / Notes:
Conformed to the zone-specific display framework by specifying that each independently controllable cooling zone is represented by a distinct color gradient spanning from no tissue contact to full tissue contact, based on the calibrated impedance values generated by the calibration algorithm of Claim 9.
Specification Support: U.S. Patent No. 11,284,561, col. 13, ll. 5–25 (describing zone-specific color-coded tissue contact map display with graduated color scales) and Fig. 8 (illustrating exemplary zone-specific color-coded tissue contact map).
Claim 13 (Dependent on Claim 9 — Conforming Amendment).  Original Claim 13 (Currently Pending):
13\. The method of claim 9, wherein the baseline impedance measurements are acquired over a period of at least five seconds.
Proposed Amended Claim 13:
13\. The method of claim 9, wherein the baseline impedance measurements are acquired <u>by sampling each of the bipolar impedance measurement and the unipolar impedance measurement</u> over a period of at least five seconds <u>at a sampling rate of at least 100 Hz prior to delivery of cryogenic fluid</u>.
Basis for Amendment / Notes:
Amended to specify the sampling rate (at least 100 Hz) and to confirm that both the bipolar and unipolar impedance measurement types are sampled during the baseline acquisition period, prior to delivery of cryogenic fluid. This additional detail further addresses the Examiner's § 112(a) concerns by demonstrating that the specification provides sufficient written description of the data acquisition parameters underlying the calibration algorithm.
Specification Support: U.S. Patent No. 11,284,561, col. 9, ll. 45–60 (describing baseline impedance data acquisition at sampling rates of 100 Hz to 1 kHz over a minimum five-second pre-ablation window, with simultaneous bipolar and unipolar measurement channels).
Claim 14 (Dependent on Claim 9 — Conforming Amendment).  Original Claim 14 (Currently Pending):
14\. The method of claim 9, wherein the cardiac chamber is a left atrium.
Proposed Amended Claim 14:
14\. The method of claim 9, wherein the cardiac chamber is a left atrium <u>and the cryoablation catheter is positioned such that at least two of the plurality of independently controllable cooling zones are in contact with tissue surrounding a pulmonary vein ostium</u>.
Basis for Amendment / Notes:
Amended to add anatomical and positional specificity relevant to the primary clinical application of pulmonary vein isolation for the treatment of atrial fibrillation. The amendment specifies that at least two of the independently controllable cooling zones are in contact with tissue surrounding a pulmonary vein ostium, reflecting the intended multi-zone engagement with target anatomy during the calibration and subsequent ablation procedure.
Specification Support: U.S. Patent No. 11,284,561, col. 7, ll. 10–30 (describing catheter deployment and positioning within the left atrium for pulmonary vein isolation, including multi-zone contact with peristial tissue).
C. Claims 15–20 (Objected-To Group — Rewritten in Independent Form)
Claim 15 (Rewritten as Independent — Substantive Amendment).  Original Claim 15 (Currently Pending):
15\. The system of claim 1, wherein the control unit is configured to automatically terminate cryogenic fluid delivery to a cooling zone upon detecting a predetermined impedance threshold indicative of transmural lesion formation at that cooling zone.
Proposed Amended Claim 15 (Rewritten in Independent Form):
15\. A cryoablation catheter system comprising:
an elongate catheter body having a proximal end and a distal end;
a cryoablation element disposed at the distal end, the cryoablation element defining a plurality of independently controllable cooling zones arranged along a longitudinal axis of the cryoablation element, each cooling zone configured to receive a separately regulated flow of cryogenic fluid to deliver variable-zone cooling to target cardiac tissue;
a plurality of impedance mapping electrodes disposed along the cryoablation element, wherein at least one impedance mapping electrode is positioned within each of the plurality of independently controllable cooling zones and is configured to measure local tissue impedance in real time during cryoablation; and
a control unit in communication with the cryoablation element and the plurality of impedance mapping electrodes, the control unit configured to:
(i) independently adjust cryogenic fluid flow to each cooling zone based on the local tissue impedance measured by the at least one impedance mapping electrode positioned within that cooling zone; and
(ii) automatically terminate cryogenic fluid delivery to an individual cooling zone of the plurality of independently controllable cooling zones upon detecting that the local tissue impedance measured by the at least one impedance mapping electrode within that individual cooling zone has reached a predetermined impedance threshold indicative of transmural lesion formation at that cooling zone, while continuing cryogenic fluid delivery to remaining cooling zones that have not reached the predetermined impedance threshold.
Basis for Amendment / Notes:
Rewritten in independent form pursuant to the Examiner's indication under MPEP § 707.07(j) that Claim 15 contains allowable subject matter. The rewritten independent Claim 15 incorporates all limitations of amended Claim 1 (the multi-zone cryoablation element, per-zone impedance electrodes with real-time measurement, and closed-loop zone-specific cryogenic fluid flow control) together with the automatic termination feature that was the subject of the Examiner's allowability indication. Critically, the rewritten claim specifies that the control unit automatically terminates cryogenic fluid delivery to an "individual cooling zone" upon detection of the predetermined impedance threshold, "while continuing cryogenic fluid delivery to remaining cooling zones that have not reached the predetermined impedance threshold." This zone-independent termination functionality — allowing selective cessation of cryoablation at zones where transmural lesion formation is confirmed while maintaining ablation at zones where treatment is still ongoing — represents the core distinguishing feature acknowledged by the Examiner as not taught or suggested by the cited prior art.
Specification Support: U.S. Patent No. 11,284,561, col. 15, ll. 1–35 (describing zone-independent automatic termination logic based on impedance threshold detection for transmural lesion confirmation); col. 16, ll. 5–30 (describing control unit architecture for simultaneous per-zone monitoring and selective termination/continuation of cryogenic fluid delivery); Fig. 9 (illustrating control flow diagram for automatic zone-specific termination with continued delivery to non-threshold zones).
Claim 16 (Dependent on Claim 15 — Conforming Amendment).  Original Claim 16 (Currently Pending):
16\. The system of claim 15, wherein the predetermined impedance threshold is adjustable by a user.
Proposed Amended Claim 16:
16\. The system of claim 15, wherein the predetermined impedance threshold is adjustable by a user <u>via a graphical interface on the control unit, and different predetermined impedance thresholds may be set for different cooling zones</u>.
Basis for Amendment / Notes:
Conformed to the multi-zone framework of rewritten independent Claim 15 by specifying that the user may set different predetermined impedance thresholds for different cooling zones via a graphical user interface on the control unit. This per-zone threshold customization enables clinicians to tailor termination criteria based on the varying tissue characteristics and anatomical positions of each cooling zone.
Specification Support: U.S. Patent No. 11,284,561, col. 16, ll. 15–30 (describing graphical user interface for per-zone impedance threshold adjustment by the operator).
Claim 17 (Dependent on Claim 15 — Conforming Amendment).  Original Claim 17 (Currently Pending):
17\. The system of claim 15, wherein the predetermined impedance threshold corresponds to an impedance drop of at least 15% from a baseline impedance value.
Proposed Amended Claim 17:
17\. The system of claim 15, wherein the predetermined impedance threshold <u>for each cooling zone</u> corresponds to an impedance drop of at least 15% from a baseline impedance value <u>measured by the at least one impedance mapping electrode within that cooling zone prior to cryogenic fluid delivery</u>.
Basis for Amendment / Notes:
Amended to tie the 15% impedance drop threshold to a per-zone baseline measurement acquired by the zone-specific impedance mapping electrode prior to cryogenic fluid delivery. This ensures that the threshold for transmural lesion detection is calibrated on a per-zone basis against the actual pre-ablation tissue impedance characteristics at each individual cooling zone location.
Specification Support: U.S. Patent No. 11,284,561, col. 15, ll. 20–35 (describing per-zone baseline impedance acquisition and percentage-based threshold calculation for transmural lesion detection).
Claim 18 (Dependent on Claim 15 — Conforming Amendment).  Original Claim 18 (Currently Pending):
18\. The system of claim 15, wherein the control unit generates an alert upon terminating cryogenic fluid delivery.
Proposed Amended Claim 18:
18\. The system of claim 15, wherein the control unit generates a <u>zone-specific visual and audible</u> alert upon automatically terminating cryogenic fluid delivery <u>to the individual cooling zone, the alert identifying which of the plurality of cooling zones has reached the predetermined impedance threshold</u>.
Basis for Amendment / Notes:
Amended to specify that the alert is zone-specific, includes both visual and audible components, and identifies which particular cooling zone has reached the predetermined impedance threshold and triggered automatic termination. This provides the clinician with actionable, zone-level feedback during the procedure.
Specification Support: U.S. Patent No. 11,284,561, col. 16, ll. 25–45 (describing zone-specific visual indicators on the control unit display and audible alert tones triggered upon automatic cryogenic fluid termination at individual cooling zones).
Claim 19 (Dependent on Claim 15 — Conforming Amendment).  Original Claim 19 (Currently Pending):
19\. The system of claim 15, further comprising a data logging module configured to record impedance measurements and cryoablation parameters over time.
Proposed Amended Claim 19:
19\. The system of claim 15, further comprising a data logging module <u>within the control unit</u> configured to record, <u>for each of the plurality of independently controllable cooling zones,</u> impedance measurements <u>from the at least one impedance mapping electrode,</u> <u>cryogenic fluid flow rates, temperature readings,</u> and <u>timestamps of automatic cryogenic fluid termination events</u> ~~cryoablation parameters over time~~.
Basis for Amendment / Notes:
Amended to add per-zone granularity to the data logging functionality and to enumerate specific parameters recorded by the data logging module: (1) impedance measurements from the zone-specific impedance mapping electrodes; (2) cryogenic fluid flow rates to each zone; (3) temperature readings at each zone; and (4) timestamps of automatic cryogenic fluid termination events for each zone. The data logging module is also specified as being located "within the control unit."
Specification Support: U.S. Patent No. 11,284,561, col. 17, ll. 5–25 (describing integrated data logging module within the control unit that records per-zone impedance, flow rate, temperature, and event timestamp data for post-procedure analysis and regulatory documentation).
Claim 20 (Dependent on Claim 15 — Conforming Amendment).  Original Claim 20 (Currently Pending):
20\. The system of claim 15, wherein the cryoablation element is configured for pulmonary vein isolation in treatment of atrial fibrillation.
Proposed Amended Claim 20:
20\. The system of claim 15, wherein the cryoablation element is configured for pulmonary vein isolation in treatment of atrial fibrillation, <u>and wherein the plurality of independently controllable cooling zones are dimensioned and arranged to simultaneously contact tissue circumferentially surrounding a pulmonary vein ostium such that each cooling zone treats a different circumferential segment of the pulmonary vein ostium</u>.
Basis for Amendment / Notes:
Amended to add structural and functional specificity regarding the physical arrangement of the independently controllable cooling zones relative to the pulmonary vein ostium anatomy. The amendment specifies that the cooling zones are "dimensioned and arranged to simultaneously contact tissue circumferentially surrounding a pulmonary vein ostium" with "each cooling zone treat[ing] a different circumferential segment of the pulmonary vein ostium." This limitation reflects the segmented, circumferential ablation approach that enables zone-independent lesion formation around the pulmonary vein os and is a distinguishing structural feature of the claimed invention.
Specification Support: U.S. Patent No. 11,284,561, col. 7, ll. 10–45 (describing dimensioning and arrangement of cooling zones for circumferential contact around pulmonary vein ostia); col. 8, ll. 50–67 (describing per-segment ablation of circumferential pulmonary vein tissue); Fig. 4 (illustrating multi-zone cryoablation element deployed at a pulmonary vein ostium with each zone contacting a different circumferential segment).
IV. SUMMARY TABLE OF AMENDMENTS
The following table provides a consolidated summary of all proposed claim amendments, organized by claim number, with the applicable rejection or objection, type of amendment, key limitation(s) added, and specification support references.
V. CERTIFICATION AND SIGNATURE BLOCK
This Claim Amendment Comparison Chart has been prepared in connection with the prosecution of U.S. Application No. 17/851,216 (SBD-001-CON2) on behalf of Solstice Biomedical Devices Ltd. and is submitted for internal review as a draft exhibit to the proposed Response to Non-Final Office Action mailed September 15, 2024.
This document is a privileged and confidential attorney work product prepared for the sole use of the client and the prosecution team. It is not intended for filing with the United States Patent and Trademark Office without express client authorization. The proposed claim amendments set forth herein are subject to further revision based on client input, technical review, and strategic considerations.
Prepared by:
CALDERWOOD & HARKNESS LLP
By: ________
Name: Wendy Schultz
Registration No.: 78,115
Title: Working Associate
Date: ________
Reviewed by:
By: ________
Name: Peter Vassiliev
Registration No.: 72,340
Title: Lead Associate
Date: ________
By: ________
Name: Dr. Claire Nakamura
Registration No.: 66,203
Title: Patent Agent (Of Counsel)
Date: ________
PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT — DRAFT FOR CLIENT REVIEW — NOT FOR FILING WITHOUT CLIENT AUTHORIZATION. This document and the information contained herein are protected by the attorney-client privilege and the work product doctrine. Any unauthorized review, use, disclosure, or distribution of this document is strictly prohibited. If you have received this document in error, please notify Calderwood & Harkness LLP immediately and destroy all copies.
Applicant: | Solstice Biomedical Devices Ltd.
Named Inventors: | Dr. Aisling Connolly and Dr. Tomás Brennan
Application No.: | U.S. 17/851,216 (Continuation — CON-2)
Parent Application: | U.S. Patent No. 11,284,561 (issued March 22, 2022, from U.S. Application No. 16/914,337)
Art Unit: | 3794
Primary Examiner: | James R. Dougherty
Supervisory Patent Examiner: | Linda M. Kowalski
Filed: | Continuation application
Internal Docket No.: | SBD-001-CON2
Prepared by: | Wendy Schultz, Reg. No. 78,115, Calderwood & Harkness LLP
Reviewed by: | Peter Vassiliev, Reg. No. 72,340, Calderwood & Harkness LLP
Dr. Claire Nakamura, Reg. No. 66,203, Calderwood & Harkness LLP
Date: | November 22, 2024
Matter No.: | SBD-IP-2021-003
Status: | DRAFT — Exhibit to Draft Response to Non-Final Office Action (mailed September 15, 2024)
Claims | Rejection / Objection | Statutory Basis | Prior Art / Ground
1–8 | Rejection | 35 U.S.C. § 103 | Obvious over U.S. Pat. No. 10,537,418 (Vantage) in view of U.S. Pat. No. 9,861,432 (Vantage) and U.S. Pub. No. 2019/0183567 (Helios)
9–14 | Rejection | 35 U.S.C. § 112(a) | Lack of written description — impedance mapping calibration algorithm insufficiently described in the specification
15–20 | Objection | Dependent on rejected base claim | Objected to as dependent on rejected Claim 1; however, indicated as containing allowable subject matter if rewritten in independent form or if base claim is amended to overcome the § 103 rejection
Claim | Rejection / Objection | Amendment Type | Key Limitation(s) Added | Specification Support (U.S. Pat. No. 11,284,561)
1 | § 103 | Substantive | Plurality of independently controllable cooling zones; per-zone impedance electrode; real-time measurement; closed-loop zone-specific control | Col. 5:15–45; Col. 8:1–30; Col. 12:10–40
2 | § 103 (dep.) | Conforming | Compliant balloon with internal partitions defining cooling zones | Col. 6:10–30
3 | § 103 (dep.) | Conforming | Dedicated lumens per cooling zone for nitrous oxide delivery | Col. 6:35–50
4 | § 103 (dep.) | Conforming | Per-zone electrode distribution (≥ 2 electrodes per zone in ≥ 2 zones) | Col. 8:15–30
5 | § 103 (dep.) | Conforming | Circumferential disposition on outer surface within each zone | Col. 8:35–50
6 | § 103 (dep.) | Conforming | Per-zone temperature sensor | Col. 9:1–15
7 | § 103 (dep.) | Conforming | Zone-specific real-time impedance map generation and display | Col. 13:1–20
8 | § 103 (dep.) | Conforming | Refresh rate ≥ 1/sec; per-zone data source | Col. 14:5–20
9 | § 112(a) | Substantive | Detailed calibration algorithm steps (a)–(c); bipolar/unipolar measurements; calibration table; temperature compensation; offset subtraction | Col. 9:25–67; Col. 10:1–45; Col. 11:10–55; Figs. 6A–6C
10 | § 112(a) (dep.) | Conforming | Linear regression model; temperature range −80°C to 37°C | Col. 10:30–50; Fig. 6B
11 | § 112(a) (dep.) | Conforming | Update interval ≤ 1 sec; iterative recalibration of steps (a)–(c) | Col. 11:35–55
12 | § 112(a) (dep.) | Conforming | Zone-specific color gradient from no contact to full contact | Col. 13:5–25; Fig. 8
13 | § 112(a) (dep.) | Conforming | Sampling rate ≥ 100 Hz; both bipolar and unipolar measurement types | Col. 9:45–60
14 | § 112(a) (dep.) | Conforming | PV ostium contact by ≥ 2 cooling zones | Col. 7:10–30
15 | Objected (allowable subject matter) | Rewritten as independent | All of amended Claim 1 + auto-termination per zone upon impedance threshold + continued delivery to remaining zones | Col. 15:1–35; Col. 16:5–30; Fig. 9
16 | Objected (dep.) | Conforming | Per-zone adjustable threshold via graphical interface | Col. 16:15–30
17 | Objected (dep.) | Conforming | Per-zone ≥ 15% impedance drop from per-zone baseline | Col. 15:20–35
18 | Objected (dep.) | Conforming | Zone-specific visual and audible alert identifying triggered zone | Col. 16:25–45
19 | Objected (dep.) | Conforming | Per-zone data logging with enumerated parameters and termination timestamps | Col. 17:5–25
20 | Objected (dep.) | Conforming | PV ostium circumferential segment-wise contact by dimensioned cooling zones | Col. 7:10–45; Col. 8:50–67; Fig. 4
Firm: | Calderwood & Harkness LLP
Address: | 600 Lexington Avenue, 22nd Floor, New York, NY 10022
Client: | Solstice Biomedical Devices Ltd.
Matter No.: | SBD-IP-2021-003
Application: | U.S. 17/851,216 (SBD-001-CON2)
Date: | November 22, 2024

PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT

CLAIM AMENDMENT COMPARISON CHART

I. INSTRUCTIONS AND LEGEND

II. SUMMARY OF REJECTIONS AND AMENDMENT STRATEGY

III. CLAIM AMENDMENT COMPARISON TABLE

Record

Parties

Dates

Amounts