# US 9,872,718 B2 · Shafts with pressure relief in cryotherapeutic catheters and associated devices, systems, and methods

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- Number: US 9,872,718 B2
- Document ID: US9872718B2
- Status: Granted
- Kind: B2
- Application number: 14/967,425
- Filed: 2015-12-14
- Published: 2016-06-16
- Granted: 2018-01-23
- Earliest claimed: 2012-04-27
- Assignees: Medtronic Adrian Luxembourg S.a.r.l.
- Applicants: Medtronic Ardian Luxembourg S.a.r.l.
- Inventors: Stephen Nash; Grace Kelly
- Web page: https://patentgrep.com/patent/US9872718B2

## CPC

- A61B 18/02: by cooling, e.g. cryogenic techniques
- A61M 25/1006: {Balloons formed between concentric tubes}
- A61M 25/10184: {Means for controlling or monitoring inflation or deflation}
- A61M 25/1025: {Connections between catheter tubes and inflation tubes}
- A61B 90/03: {Automatic limiting or abutting means, e.g. for safety}
- A61B 2018/00005: {Cooling or heating of the probe or tissue immediately surrounding the probe}
- A61B 2018/00023: {closed, i.e. without wound contact by the fluid}
- A61B 2018/00166: {Multiple lumina}
- A61B 2018/0022: {Balloons}
- A61B 2018/0212: {using an instrument inserted into a body lumen, e.g. catheter}
- A61B 2018/0262: {using a circulating cryogenic fluid}
- A61B 2018/0268: {with restriction of flow}
- A61B 2090/032: {pressure limiting, e.g. hydrostatic}
- A61B 2090/037: {with a frangible part, e.g. by reduced diameter}
- A61M 2025/1061: {having separate inflations tubes, e.g. coaxial tubes or tubes otherwise arranged apart from the catheter tube}
- F04C 2270/041: Controlled or regulated
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}
- F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS

## Abstract

Cryotherapeutic systems with features that can facilitate pressure relief in the event of exhaust-passage blockage and associated devices, systems, and methods are disclosed herein. A cryotherapeutic system configured in accordance with a particular embodiment can include an elongated shaft having a distal portion and a pressure-relief portion proximal to the distal portion. The cryotherapeutic system can further include a supply lumen, an exhaust passage, and a balloon configured to receive refrigerant from the supply lumen and to exhaust refrigerant to the exhaust passage. The pressure-relief portion can be configured to release refrigerant from the exhaust passage when a pressure of refrigerant in the exhaust passage exceeds a threshold pressure less than a pressure rating of the balloon. The pressure-relief portion, for example, can include a rupture element configured to rupture at about the threshold pressure.

## Claims

### Claim 1

A cryotherapeutic catheter comprising:
an elongate shaft having a distal end portion, a pressure-relief portion proximal to the distal end portion, and a collapsible portion proximal to the pressure-relief portion, wherein the shaft is configured to move longitudinally within a guide passage defined by a tubular guide catheter, wherein the distal end portion of the shaft is configured to sealingly contact the guide catheter and thereby occlude an annular gap between the shaft and the guide catheter;
a supply lumen carried by the shaft;
an exhaust passage carried by the shaft; and
a balloon at the distal end portion of the shaft wherein the balloon is configured to receive refrigerant from the supply lumen and to exhaust refrigerant to the exhaust passage,
wherein the pressure-relief portion of the shaft is configured to rupture and thereby release refrigerant therethrough from the exhaust passage when a pressure of refrigerant within the exhaust passage exceeds a threshold pressure less than a pressure rating of the balloon, and
wherein the collapsible portion of the shaft configured to collapse in response to pressure from refrigerant released from the exhaust passage via the pressure-relief portion of the shaft.

### Claim 2 (depends on 1)

The cryotherapeutic catheter of claim 1 wherein the distal end portion of the shaft includes an annular flow restrictor configured to sealingly contact the guide catheter.

### Claim 3 (depends on 2)

The cryotherapeutic catheter of claim 2 wherein the flow restrictor is compressible.

### Claim 4 (depends on 1)

The cryotherapeutic catheter of claim 1, wherein
the shaft has a first wall strength at its distal end portion;
the shaft has a second wall strength at its pressure-relief portion; and
the second wall strength is less than the first wall strength.

### Claim 5 (depends on 4)

The cryotherapeutic catheter of claim 4, wherein the second wall strength is selected to cause the pressure-relief portion of the shaft to rupture when the pressure of refrigerant within the exhaust passage exceeds the threshold pressure.

### Claim 6 (depends on 4)

The cryotherapeutic catheter of claim 4, wherein the shaft includes a butt joint between its distal end portion and its pressure-relief portion.

### Claim 7 (depends on 4)

The cryotherapeutic catheter of claim 4, wherein the shaft includes a lap joint between its distal end portion and its pressure-relief portion.

### Claim 8 (depends on 4)

The cryotherapeutic catheter of claim 4 wherein the second wall strength is less than 80% of the first wall strength.

### Claim 9 (depends on 1)

The cryotherapeutic catheter of claim 1 wherein the pressure-relief portion of the shaft includes a membrane configured to rupture when the pressure of refrigerant within the exhaust passage exceeds the threshold pressure.

### Claim 10 (depends on 1)

The cryotherapeutic catheter of claim 1 wherein the pressure-relief portion of the shaft is a scored portion of a wall of the shaft.

### Claim 11 (depends on 1)

The cryotherapeutic catheter of claim 1 wherein the shaft has a smaller diameter at its pressure-relief portion than at its distal end portion.

### Claim 12 (depends on 1)

The cryotherapeutic catheter of claim 1 wherein the shaft has a smaller diameter proximal to its pressure-relief portion than at its distal end portion.

### Claim 13 (depends on 1)

The cryotherapeutic catheter of claim 1 wherein the collapsible portion of the shaft has a length of at least 100 cm.

### Claim 14 (depends on 1)

The cryotherapeutic catheter of claim 1, wherein the pressure rating of the balloon corresponds to a burst pressure of the balloon.

### Claim 15 (depends on 1)

The cryotherapeutic catheter of claim 1, wherein the shaft is configured to move longitudinally within a guide passage defined by a tubular guide catheter that is 8 French or smaller.