# US 9,750,556 B2 · Cryotreatment devices and methods of forming conduction blocks

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- Number: US 9,750,556 B2
- Document ID: US9750556B2
- Status: Granted
- Kind: B2
- Application number: 15/132,934
- Filed: 2016-04-19
- Published: 2016-08-11
- Granted: 2017-09-05
- Earliest claimed: 2003-04-10
- Assignees: Boston Scientific Scimed, Inc.
- Applicants: Boston Scientific Scimed Inc.
- Inventors: Daniel M. Lafontaine
- Web page: https://patentgrep.com/patent/US9750556B2

## CPC

- A61B 18/02: by cooling, e.g. cryogenic techniques
- A61B 18/0218: {with open-end cryogenic probe, e.g. for spraying fluid directly on tissue or via a tissue-contacting porous tip}
- A61B 2018/0212: {using an instrument inserted into a body lumen, e.g. catheter}
- A61B 2018/0262: {using a circulating cryogenic fluid}
- A61B 2018/0293: {using an instrument interstitially inserted into the body, e.g. needle}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

Cryotreatment devices and methods of ablating tissue within the body are disclosed. A cryotreatment device in accordance with an exemplary embodiment of the present invention includes an elongated member having one or more needle-like ablation tips configured to induce necrosis at a target site within the heart. A cooling fluid such as a cryogen may be injected through a lumen extending into the distal portion of the device. The ablation tips can be configured to pierce and ablate surrounding tissue, blocking electrical stimuli that can cause fibrillations or other arrhythmias of the heart. The device may also include means for controlling the transmural depth at which the ablation tips are inserted into the cardiac tissue. Methods of forming a contiguous line of conduction block in accordance with the present invention are also disclosed.

## Claims

### Claim 1

A method for cyrosurgically inducing controlled necrosis at a target site within a heart using a cryotreatment device having a proximal portion, a distal portion, at least one lumen extending from the proximal portion to the distal portion, and a plurality of ablation tips at the distal portion, the ablation tips in fluid communication with the lumen, each of the ablation tips retractable from a deployed position, the method comprising:
advancing the cryotreatment device to the target site;
inserting the deployed ablation tips into cardiac tissue at the target site;
retracting each of the inserted ablation tips from the deployed position while measuring a depth at which the ablation tip is inserted into the cardiac tissue; and
injecting a cryogenic fluid through the lumen to the ablation tips once each of the ablation tips have been retracted to a desired measured depth, freezing the cardiac tissue at the target site.

### Claim 2 (depends on 1)

The method of claim 1, wherein retracting each of the inserted ablation tips from the deployed position includes retracting a control wire connected to the ablation tip and extending proximally to the proximal portion of the cryotreatment device.

### Claim 3 (depends on 1)

The method of claim 1, wherein retracting each of the inserted ablation tips from the deployed position includes retracting the ablation tip a distance from 0.5 cm to 3.0 cm from the deployed position.

### Claim 4 (depends on 1)

The method of claim 1, wherein measuring the depth at which the ablation tip is inserted into the cardiac tissue is by an ultrasonic probe.

### Claim 5 (depends on 1)

The method of claim 1, wherein the plurality of ablation tips are configured to form a line of conduction block at the target site.

### Claim 6 (depends on 1)

The method of claim 1, wherein injecting the cryogenic fluid through the lumen includes:
supplying the cryogenic fluid to the lumen at the proximal portion of the cryotreatment device; and
ejecting the cryogenic fluid from the lumen through one or more apertures at the distal end of the croytreatment device, the apertures configured to cool the cryogenic fluid.

### Claim 7 (depends on 1)

The method of claim 1, wherein injecting the cryogenic fluid through the lumen includes injecting liquid nitrous oxide into the lumen.

### Claim 8 (depends on 1)

The method of claim 1, wherein injecting the cryogenic fluid through the lumen includes cooling the ablation tips to a temperature of about −40° C. to about −100° C.

### Claim 9 (depends on 1)

The method of claim 1, wherein the plurality of ablation tips are retracted from the fully deployed position to form a line of conduction block at the target site.

### Claim 10 (depends on 1)

The method of claim 1, wherein advancing the cryotreatment device to the target site includes inserting the cryotreatment device through a previously positioned guide catheter.