US20150057599A1

US20150057599A1 - Pulmonary artery ablation catheter

Info

Publication number: US20150057599A1
Application number: US14/530,588
Authority: US
Inventors: Shaoliang Chen
Original assignee: Shaoliang Chen
Current assignee: Pulnovo Medical (wuxi) Co Ltd
Priority date: 2012-11-13
Filing date: 2014-10-31
Publication date: 2015-02-26
Also published as: CN102908191A; US20140180277A1; KR20140088087A; EP2910213B1; US10874454B2; BR112014007594B1; EP2910213A4; RU2587945C2; RU2014112769A; KR101640329B1; WO2014075415A1; US20160338774A1; RU2587945C9; JP2015502823A; EP2910213A1; CN103142304B; JP6054415B2; BR112014007594A2; CN103142304A

Abstract

A multi-pole synchronous pulmonary artery radiofrequency ablation catheter, wherein an adjustment apparatus is arranged on a control handle; a catheter body is hollow, and a cavity is arranged therein; a lead wire, a temperature sensing wire and a pull wire are arranged in the cavity; one end of the catheter body is flexible, and the flexible end is connected to an annular ring; the other end of the catheter body is connected to the control handle; one end of the pull wire is connected to the flexible end, and the other end of the pull wire is connected to the adjustment apparatus on the control handle, the tension of the pull wire is adjusted through the adjustment apparatus to achieve radian control of the flexible end; a shape memory wire is arranged in the annular ring, one end of the shape memory wire extends to the end of the annular ring and the other end of the shape memory wire passes through the root of the annular ring and is fixed on the flexible end of the catheter body; the annular ring is provided with an electrode group with each electrode connected to the lead wire and temperature sensing wire; the lead wire and temperature sensing wire go through the catheter body and are electrically connected to the control handle. The device uses cold saline perfusion method to protect the vascular intima and possesses advantages of simple operation, short operation time and controllable precise ablation. The device can be used to treat pulmonary hypertension with pulmonary denervation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser. No. 14/079,230, filed on Nov. 13, 2013, which claims priority to Chinese Application No. 201210453470.4, filed on Nov. 13, 2012 and Chinese Application No. 201310103141.1, filed on Mar. 27, 2013, the entire contents of each of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTIONS

1. Field of the Inventions
The present inventions relate to medical devices for treatment of pulmonary hypertension in the pulmonary artery by de-sympathetic methods, for example, with pulmonary artery catheters, as well as methods for diagnosis and method of treating pulmonary hypertension.
2. Description of the Related Art
Pulmonary hypertension is to be an intractable diseases in the cardiovascular, respiratory, connective tissue, immune and rheumatic systems. Currently available clinical treatments of pulmonary hypertension are limited and therapy efficacy thereof is poor. Incidence of primary pulmonary hypertension is low but those secondary to pulmonary interstitial fibrosis, connective tissue disease, portal hypertension, chronic pulmonary artery embolism and left heart system disorder are common, with five-year mortality rate up to 30%. Therefore, prevention and treatment for pulmonary hypertension is of great significance.
In recent years, new targeted drugs have emerged based on the research into the pathogenesis of pulmonary hypertension. However, some of those drugs have serious limitations including many side effects, inappropriate dosage form, expensive cost and unreliable efficacy, and thus many have not been widely applied in clinical treatment.

SUMMARY OF THE INVENTIONS

An aspect of at least one of the inventions disclosed herein includes the realization, supported by experimental data which demonstrates, that pulmonary hypertension is associated with hyper sympathetic activity in pulmonary artery and hyperactive baroreceptor. Blocking the sympathetic nerves in the pulmonary artery or permanently damaging the baroreceptor structure and function thereof can decrease the pulmonary artery pressure, which can provide more successful treatments of pulmonary hypertension.
Some of the embodiments disclosed herein provide a pulmonary artery ablation catheter for treatment of pulmonary hypertension in the pulmonary artery by a de-sympathetic method. In some embodiments, the catheter only heats the adherent tissue rather than the blood. Additionally, in some embodiments, the catheter can be configured to provide cold saline perfusion at or near the ablation site to protect the vascular intima. Some of the embodiments can also provide advantages of simple operation, short operation time and controllable, precise ablation.
In some embodiments, a pulmonary artery ablation catheter can comprise a control handle, a catheter body and an annular ring. The control handle can be provided with an adjustment apparatus. The catheter body can be hollow and can include a cavity. One or a plurality of lead wires, one or more temperature sensing wires and one or more pull wires can be arranged in the cavity. One end of the catheter body can be flexible. The flexible end can be connected to an annular ring and the other end of the catheter body can be connected to the control handle. One end of the pull wire can be connected to the flexible end and the other end of the pull wire can be connected to the adjustment apparatus. Tension in the pull wire can be adjusted through the adjustment apparatus to achieve shape control, such as curvature control, of the flexible end. A shape memory wire can be arranged in the annular ring. One end of the shape memory wire can extend to the end of the annular ring and the other end of the shape memory wire can pass through the root of the annular ring and can be fixed on the flexible end of the catheter body. The annular ring can be provided with an electrode group with each electrode connected to the one or more lead wires and the one or more temperature sensing wires. The lead wire(s) and the temperature sensing wire(s) extend through the catheter body and are electrically connected to the control handle.
An infusion tube can be arranged in the cavity of the catheter body and a through hole can be arranged on one or more of the electrodes. The infusion tube can be connected to the electrodes through the annular ring. The transfused fluid flows out from the through hole and thus can be used for cooling purposes during ablation procedures.
The electrodes on the annular ring can be made of a material selected from the group consisted of platinum-iridium alloy, gold, stainless steel and nickel alloy, with the number in the range of 3-30 electrodes, a diameter in the range of 1.3-2.0 mm, a length in the range of 1.2-4 mm and an edge space between adjacent electrodes in the range of 0.5-10 mm.
The flexible end of the catheter body can be provided with a counterbore, an inner diameter of the counterbore can be sized to fit an outer diameter of the root of the annular ring, and thus the root of the annular ring can be inserted and fixed into the counterbore.
The flexible end of the catheter body is provided with a groove in which a connector is arranged, one end of the connector is connected to the pull wire and the other end of the connector is connected to the shape memory wire.
The material of the shape memory wire in the annular ring can be a shape memory alloy selected from the group consisted of nickel titanium alloy, stainless steel or titanium, with a diameter of 0.25-0.5 mm. The diameter of the annular ring can be 12-40 mm. For example, the annular ring can be configured so as to be biased toward a circumferential shape, having a desired diameter (e.g., in the range of 12-40 mm), for example, with the use of a memory shape material. Preferably, 10 electrodes are arranged on the annular ring. The width of naked section of the electrode is 0.75 mm, and the space therebetween is 5 mm.
The flexible end can be made of medical polymer materials with a length in the range of 30-80 mm. The connection can be achieved by a UV-curing adhesive. The joint between the flexible end and the annular ring can be sealed.
The pull wire is made of stainless steel or nickel-titanium alloy. The outside of pull wire is provided with a spring coil, and the outside of the spring coil is provided with a spring sleeve made of polyimide material.
In some embodiments, the catheter can be packaged into a kit including a plurality of different annular rings that are biased to different diameters. In some embodiments, where the annular rings, flexible bodies, and handles are permanently connected together, a kit can include a plurality of different catheters, each having handles and flexible bodies, but differently sized annular rings.
In some embodiments and/or methods of use, the catheter can heat, with radiofrequency energy, the tissue in direct contact with the electrode and avoid heating blood. Additionally, the catheter can provide advantages of simple operation, short operation time and controllable precise ablation. The catheter body can be preferably made of a polymer material, which is a poor heat conductor, so that it can avoid transmitting the heat when heating the electrodes to the flowing blood contacting the catheter body, thereby effectively avoid heating the blood.
Furthermore, the shape or curvature of the flexible end can be adjusted by operating the adjustment apparatus, which allows the operator to control the handle with one hand, so as to adjust the curvature of the flexible end easily for purposes of placement of the annular ring and the electrodes. As such, after achieving the desired placement, the electrodes on the annular ring can be pressed against the pulmonary artery and achieve ablation of pulmonary artery intima. During application of the radiofrequency current, the electrodes can produce high local temperature and cause severe damage on the vascular intima.
Thus, in some embodiments, the catheter can be configured to provide cold saline perfusion to cool down the local temperature. When the electrodes receive the current, the saline is automatically and uniformly diffused through the through holes, which can provide beneficial cooling, for example, decreasing the local temperature to be below 60° C., thereby protecting the vascular intima.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of an embodiment of a catheter in accordance with an embodiment;

FIG. 2 is a partially enlarged view of Part B identified in FIG. 1;

FIG. 3 is schematic sectional view taken along line A-A′ of FIG. 1;

FIG. 4 is a schematic structural view of an optional outer surface of an electrode that can be used with the catheter of FIG. 1.

FIG. 5 is a front elevational and partial sectional view of a human heart;

FIG. 6 is a schematic sectional diagram of a pulmonary artery trunk including a distal portion of a main pulmonary artery and the proximal portions of the left and right pulmonary arteries;

FIGS. 7A and 7B are photographs of the inner surfaces of two canine pulmonary arteries that have been dissected and laid flat;

FIG. 8 is a schematic diagram of segmentations of dissected pulmonary arteries including the distal portion of the main pulmonary artery and the proximal portions of the left and right pulmonary arteries;

FIG. 9 is a diagram of three of the segmentations identified in FIG. 8;

FIGS. 10A-10D are enlargements of microscopy slides corresponding to the portions identified as S1-S4 of level A1 of the right pulmonary artery of FIG. 9;

FIG. 11 is a photograph of microscopy of the portion identified as S6 of level A9 of the main pulmonary artery of FIG. 9;

FIG. 12 is a posterior and perspective view of a model of the left pulmonary artery of FIGS. 7A and 7B;

FIG. 13 is an anterior view of the left pulmonary artery of FIG. 12;

FIG. 14A is a diagram identifying the location corresponding to microscopy of six different locations on level A9 of the main pulmonary artery of FIG. 8;

FIG. 14B is a table showing reductions in PAP resulting from the use of different ablation operating parameters;

FIG. 15A is a perspective view of a catheter device that can be used to perform pulmonary denervation;

FIG. 15B is an enlarged end view of a distal end of the catheter of FIG. 15A with indicia indicating positions of ten (10) RF electrodes;

FIG. 15C is a perspective view of a controller that can be used for controlling the catheter of FIG. 15A during an ablation procedure;

FIG. 15D is a top plan view of the controller of FIG. 15C;

FIG. 15E is a perspective view of the controller connected to the catheter device of FIG. 15A;

FIG. 16A is a fluoroscope image of a sheath device inserted into the main pulmonary artery for guiding the catheter device of FIG. 15A into the main pulmonary artery;

FIGS. 16B-16D are additional fluoroscope images of the catheter device of FIG. 15A having been inserted and expanded within the left pulmonary artery of a human patient.

FIG. 16D illustrates a position used for ablation and arterial denervation of the left pulmonary artery of the patient;

FIG. 16E illustrates the catheter of FIG. 15A being positioned within the main pulmonary artery of the patient in a position used for ablation;

FIGS. 16F and 16G illustrate the catheter of FIG. 15A being positioned in the proximal right pulmonary artery and being pushed (FIG. 16F) and pulled (FIG. 16G) to determine if the catheter is properly seated for purposes of ablation;

FIG. 16H is a fluoroscope image of the catheter of FIG. 15A in a position for performing ablation in a proximal portion of the right pulmonary artery;

FIG. 17A is a schematic diagram of the trunk of a pulmonary artery and identifying locations for ablation in a distal portion of a main pulmonary artery;

FIG. 17B is a schematic diagram of a pulmonary artery trunk and identifying locations for ablation in proximal portions of the left and right pulmonary arteries;

FIG. 18A is a schematic diagram of a pulmonary artery trunk identifying a position for ablation in a portion of the left pulmonary artery proximal to a pulmonary artery duct;

FIG. 18B is a schematic diagram of points of ablation in the anterior wall of the ablation position identified in FIG. 18A;

FIG. 19A is a schematic diagram of a pulmonary artery trunk identifying a position for ablation in a proximal portion of the right pulmonary artery for treatment of unilateral chronic thrombotic embolism;

FIG. 19B is an enlarged schematic diagram of the portion identified in FIG. 20A and indicating positions for ablation in the anterior wall of the proximal portion of the right pulmonary artery.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following examples further illustrate embodiments of the present inventions, but should not be considered as to limit the present inventions. Without departing from the spirit and essence of the present inventions, modification or replacement of the method, steps or conditions of the embodiments disclosed below still falls in the scope of the present inventions.
If not otherwise specified, the technical means used in the embodiments are conventional means well known by a person skilled in the art.

Example 1

Through the example below and with reference to FIGS. 1-3, some of the technical solutions that can be achieved by various embodiments are further described below.
In some embodiments, a multi-pole synchronous pulmonary artery radiofrequency ablation catheter for de-sympathetic in the pulmonary artery can include a catheter body 1 that has a distal end and a proximal end. The distal end can be provided with a flexible end 3 and the proximal end can be provided with a control handle 2. A pull wire can extend in the catheter body.
Preferably, the catheter body can be made of a polymer material, which is a poor heat conductor, so that it can avoid transmitting or reduce the amount of heat transferred from the electrodes to the flowing blood contacting the catheter body, and thereby can better prevent the electrode from heating the blood flow.
The flexible end 3 can include a proximal end and a distal end. An annular ring 4 can be arranged on the distal end. The flexible end 3 can be soft relative to the rest of the catheter body. The annular ring 4 can be provided with a plurality of electrodes 5, wherein each electrode 5 can be configured to sense or extract neural electrical signals, sense temperature and conduct ablation. Each of the electrodes can be connected to lead wires and temperature sensing wires, which extend through the catheter body to the control handle, thus is electrically connected to the control handle. One or more temperature sensing wires can be embedded under each electrode for precise monitoring of the temperature during ablation. Additionally, in some embodiments, the temperature sensing wires can be connected to a thermocouple connected to an inner facing side of the electrodes 5, or can include integrated thermocouples. Other configurations can also be used.
A shape memory wire can be arranged in the annular ring 4, and a distal end of the shape memory wire can extend to the distal end of the annular ring 4. The proximal end of the shape memory wire can be fixed to the distal end of the flexible end. The shape memory wire in the annular ring 4 can be preferably made of various shape memory alloys such as nickel-titanium alloy, stainless steel or titanium, with a diameter in the range of 0.25-0.5 mm.
The diameter of the annular ring is in the range of 12-40 mm. For example, the shape memory wire can be configured to bias the annular ring 4 to a desired diameter, such as in the range of 12-40 mm. Additionally, in some embodiments, the pull wire can be used the change or adjust the diameter of the annular ring 4 through a range of diameters including 12-40 mm or other ranges.
The length of the flexible end can be in the range of 30-80 mm, and can be made of medical polymer materials such as fluorine, polyesters, polyurethane, polyamide and polyimide. A counterbore can be arranged on the distal end of the flexible end, the proximal end of the annular ring can be fixed in the counterbore, wherein the proximal end of the annular ring is a ground thin end.
A pull wire can be embedded in the catheter body, and one end of the pull wire can be fixed to the control handle. The curvature of the flexible end can be controlled by operating the control handle. For example, one end of the pull wire can be fixed to a control button on the handle and the curvature of the flexible end can be controlled by operating the button. This allows the operator to control the handle with one hand and adjust the curvature of the flexible end easily, so that the electrodes 5 on the annular ring 4 can be pressed into contract with the pulmonary artery and achieve acceptable ablation of pulmonary artery intima.
Furthermore, a counterbore can be made on the distal end of the flexible end 3, and its depth can be set according to actual needs, preferably with a depth in the range of 2-8 mm. The proximal end of the annular ring 4 can be a ground thin end, and an outer diameter of the ground thin end fits an inner diameter of the counterbore. The ground-thin end can be inserted into the flexible end 3 and can be fixed to the distal end of the flexible end 3 by bonding, welding or other suitable means, preferably by UV-curing adhesive. The excess glue may be used to seal the distal end of the flexible end 3 and the proximal end of the annular ring 4.
FIG. 1 shows a schematic structural diagram of multi-pole synchronous pulmonary artery radiofrequency ablation catheter. The annular ring 4 can be arranged at the distal end of the flexible end 3. The annular ring 4 can be an annular structure, the radius of the annular ring 4 can be effected with shape memory wire.
The annular ring 4 can be provided with a plurality of electrodes 5. Each electrode 5 can be configured to extract or detect neural electrical signals, sense the temperature and conduct ablation. The number of electrodes 5 can vary from the range of 3 to 30, preferably 5 to 20. The electrodes 5 are made of platinum-iridium alloy, gold, stainless steel or nickel alloy. The electrode diameter can be generally 1.3-2.0 mm, and the length of the electrode 5 can be generally in the range of 1.2-4 mm, more suitably 2-3.5 mm. Edge space between the adjacent electrodes suitably can be in the range of 0.5-10 mm, more suitably 1-5 mm.
The pull wire 8 can be preferably made of stainless steel or nickel-titanium. As shown in FIG. 2 and FIG. 3, the distal end of the pull wire 8 extends through a hollow cavity 9 to the proximal end of the annular ring 4, and can be fixed to the distal end of the flexible end 3. The method used for fixing the pull wire 8 to the distal end of the flexible end 3 can be any known method in the prior art.
Optionally, a groove can be arranged on the distal end of the flexible end 3, and a connector 11 can be arranged in the groove. One end of the connector 11 can be connected to the pull wire 8 and the other end of the connector 11 can be connected to the shape memory wire 12. The connector 3 can be fixed to the distal end of the flexible end 3 by injecting glue such as UV-curing adhesive into the groove.
A segment of pull wire 8 extends in the flexible end 3 and a segment of pull wire 8 extends in the catheter body 1. The pull wire can be preferably jacketed with a coil spring 13, and the coil spring 13 can be jacketed with a spring sleeve 14. The spring sleeve 14 may be made of any suitable material, preferably a polyimide material.
The proximal end of the pull wire 8 can be fixed on or in the control handle 2, which can be provided with an adjustment apparatus, and the adjustment apparatus can be configured to adjust the curvature or the diameter of the annualar ring 4.
Lead wire 6, as shown in FIGS. 2 and 3, extends through the lead wire cavity 10 to the lead wire cavity of the annular ring 4. The distal end of the lead wire 6 can be connected to electrode 5. The distal end of the lead wire 6 can be fixed to electrode 5 by welding. In some embodiments, the catheter includes one lead wire 6 for each of the electrodes 5.
The distal end of the temperature sensing wire 7 can be embedded under the electrode 5 and the distal end of the temperature sensing wire 7 can be fixed on electrode 5 by bonding, welding or other suitable means. The temperature sensing wire 7 can extend into the catheter body 1 in the lead wire cavity 10 of the flexible end 3 and then extend out from the control handle 2 and can be connected to a temperature control device. In some embodiments, the catheter includes one temperature sensing wire 7 for each of the electrodes 5.
When using the catheter, the pull wire 8 can be operated through the control handle 2 in order to deflect the flexible end 3, thereby providing enhanced control for the user when positioning the annular ring 4 in a desired location, such as an orifice of the pulmonary artery. Then, with the electrodes 5 fully contacting the pulmonary artery. At this time, the electrodes 5 can be energized for performing ablation on pulmonary artery intima.
The multi-electrode design according to the some embodiments, can improve the efficacy and safety of ablation, achieve signal analysis and preferably simultaneous ablation by a plurality of electrodes. This can also improve target accuracy, achieve timely judgment of ablation effect and save operation time. For example, with the annular ring 4 in a desired location, the electrodes can be individually activated to perform ablation at selected sites. This can be a benefit because in some methods of treatment described below, ablation can be performed at selected sites, less than the entire circumferential surface of certain anatomy.

Example 2

A multi-pole synchronous pulmonary artery radiofrequency ablation catheter comprises a control handle 2, a catheter body 1, and an annular ring 4. The control handle 2 can be provided with an adjustment apparatus, the catheter body 1 can be hollow, and a cavity can be arranged in the catheter body 1. One or more lead wires 6, temperature sensing wires 7 and a pull wire 8 can be arranged in cavity.
One end of catheter body can be flexible, and the flexible end 3 can be connected to the annular ring 4. The other end of the catheter body can be connected to the control handle 2. One end of the pull wire 8 can be connected to the flexible end 3, and the other end of the pull wire 8 can be connected to the adjustment apparatus of the control handle, the adjustment apparatus adjusts the tension of the pull wire 3 to control the curvature of the flexible end. This allows the operator to control the handle with one hand and adjust the curvature of the flexible end 3 easily. Thereby the electrodes 5 of the annular ring 4 can be pressed against to better contact an inner surface of a desired anatomy, such as a pulmonary artery, so as to enhance ablation of pulmonary artery intima.
A shape memory wire 12 can be arranged in the annular ring 4. One end of the shape memory wire 12 can extend to the end of the annular ring 4, and the other end of the shape memory wire 12 goes through the root of the annular ring 4 and can be fixed on the flexible end 3 of the catheter body.
The annular ring 4 can also be provided with an electrode group. Each electrode 5 can be connected to a lead wire 6 and a temperature sensing wire 7 and can be configured to extract or detect the nerve electrical signals, sense the temperature and conduct ablation. The lead wires 6 and temperature sensing wires 7 can extend through the catheter body 1 and can be electrically connected to the control handle 2. The control handle 2 can be connected to an external temperature control device.
The annular ring electrodes 5 can be made of a material selected from the group consisted of platinum-iridium alloy, gold, stainless steel and nickel alloy material, with the number in the range of 3-30, a diameter in the range of 1.3-2.0 mm, a length in the range of 1.2-4 mm and an edge space between adjacent electrodes in the range of 0.5-10 mm.
The flexible end 3 of the catheter body can have a counterbore. An outer diameter of the root of the annular ring 4 can fit an inner diameter of the counterbore. The root of the annular ring 4 can be inserted into the counterbore and fixed.
The flexible end 3 of the catheter body can be provided with a groove. A connector 11 can be arranged in the groove. One end of the connector can be connected to the pull wire 8 and the other end of the connector can be connected to the shape memory wire 12.
The shape memory wire can be made of shape memory alloy such as nickel titanium alloy, stainless steel or titanium, with a diameter in the range of 0.25-0.5 mm. The diameter of the annular ring 4 can be in the range of 12-40 mm. Preferably, 10 electrodes are arranged on the annular ring, and the width of naked (exposed) side of electrodes can be 0.75 mm, and the space therebetween can be 5 mm.
The flexible end 3 of the catheter body can be made of medical polymer materials such as fluorine, polyesters, polyurethane, polyamide and polyimide, with a length in the range of 30 mm to 80 mm.
The connection can be via UV-curing adhesive. The joint between the flexible end of the catheter body and the annular ring can be sealed. The pull wire can 8 be made of stainless steel or nickel-titanium alloy. The pull wire 8 can be jacketed with a coil spring 13, and the coil spring 13 can be jacketed with a spring sleeve 14 made of polyimide material.

Example 3

Example 3 is similar to Example 1 and Example 2, and the differences can include an infusion tube arranged in the catheter body, a group of evenly distributed through holes 15 (FIG. 4) arranged on one or more of the electrodes 5, with a bore diameter of 1 μm. One end of the infusion tube can be connected to the electrodes 5 through the annular ring 4 such that fluid diffuses out from the through holes 15 on each of the electrodes 5. For example, the annular ring 4 can include or define at least one lumen extending between a proximal end of the annular ring 4 and to the through holes 15 so as to form a closed fluidic connection. In such embodiments, a distal end of the infusion tube can be connected to the proximal end of the lumen in the annular ring 4. The other end of the infusion tube can be connected to a transfusion system, such as a constant-flux pump or other known pumps.
When electrodes 5 generates current, the liquid automatically diffuses from the through holes 15. The transfused liquid can be saline. The cold saline (4° C.) perfusion can help decrease local temperature. When the electrode generates current, the saline can automatically diffuse from the through holes 15, and thus can allow the local temperature to be controlled to a desired temperature, such as to below 60° C. and thereby protect the vascular intima.
FIG. 5 is a schematic diagram of a human heart and surrounding vasculature, which can be an environment in which the catheter of FIGS. 1-4 can be used to perform ablation treatments such as, for example, but without limitation, denervation of the pulmonary artery. In some methods of treatment, access to the inner walls of the main pulmonary artery as well as the left and right pulmonary arteries can be achieved by passing a catheter, using well known techniques, into a femoral vein, upwardly into the inferior vena cava (lower left hand corner of FIG. 5). The catheter can then be pushed upwards into the right atrium, down into the right ventricle, then up through the pulmonary semilunar valve into the trunk of the main pulmonary artery. As used herein, the term main pulmonary artery (MPA) includes the proximal end of the main pulmonary artery which is the furthest upstream end of the main pulmonary artery, at the pulmonary semilunar valve, up to the bifurcation of the main pulmonary artery. The distal portion of the MPA includes the portions of the MPA near the bifurcation of the MPA into the left and right pulmonary arteries (LPA, RPA).
Similarly, the proximal ends of the RPA and LPA are those ends of the LPA and RPA which are adjacent and connected to the distal end of the MPA. The distal direction along the LPA and RPA would be the downstream direction of blood flow through the LPA and RPA toward the left and right lungs, respectively.
Thus, using well known techniques, a catheter can be used to provide access to the proximal and distal portions of the MPA as well as the proximal and distal portions of the LPA and RPA.
FIG. 6 is a schematic diagram of the “trunk” of the pulmonary artery. As used herein, the “trunk” of the MPA is intended to include at least the distal portion of the MPA and the proximal portions of the LPA and RPA. FIG. 6 also includes a schematic representation of a carina at the branch of the LPA and RPA from the MPA.
As described below, an aspect of at least some of the inventions disclosed herein includes the realization that the trunk of the pulmonary artery of certain animals, including canine and humans, can include concentrated bundles of sympathetic nerves extending from the MPA into the LPA and RPA. For example, it has been discovered that there are higher concentrations of sympathetic nerves on the anterior sides of the MPA and in particular, in the vicinity of the distal portion of the MPA. Additionally, it ahs been discovered that the sympathetic nerves bifurcate from this area of higher concentration into the anterior side of the proximal portions of the LPA and RPA. In the area of these proximal portions, it has also been discovered that higher concentrations of the sympathetic nerves extend upwardly and toward the posterior side of the LPA and RPA.
Thus, in accordance with some of the inventions disclosed herein, ablation is performed in the distal portion of the MPA and the proximal portions of the LPA and RPA. In some embodiments ablation is preferentially performed on the anterior side of the inner walls of these structures. In some embodiments, ablation is performed preferentially on the anterior side of the proximal portion of the MPA and on the anterior side and an upper portion of the proximal portions of the LPA and RPA, such as at approximately the upper conjunctive site of the distal portion of the main pulmonary artery at the left and right pulmonary arteries. As such, high success rates of sympathetic nerve denervation can be achieved as well as high success rates of reduction or elimination of the symptoms of pulmonary hypertension.
It is widely accepted that all vascular walls are regulated by sympathetical and parasympathetical nervous systems. Particularly, pulmonary vessels are known to be innervated by sensory nerve fibers. Previous studies have demonstrated that sympathetic noradrenergic innervation density along the pulmonary artery is highest at its proximal segments and then decreases toward the periphery, a typical finding that is different than arteries in other organs where highest innervation density is found at the level of the smallest arterioles. However, the conclusions of the above-noted study were based on procedures in which the identification of innervation in the pulmonary artery was mainly based on the stimulation of sympathetical nerves or equivalent methods, without direct evidence or other location of sympathetical nerve fibers. However, it has been discovered that some of the conclusions of the above-noted study are incorrect, through the use of techniques for identifying the presence and location of sympathetical nerves in the pulmonary artery using direct labeling techniques.
In particular, experimental procedures were approved by the Institutional Animal Care and Use Committees of the Nanjing Medical University and were performed in accordance with the National Guide for the Care and Use of Laboratory Animals. Mongolia dogs (n=6, weight 7.8±1.2 kg) were obtained from the Nanjing Experimental Center (Nanjing, China). All animals were housed in a single room at 24° C. on a 12 h-light/12 h-dark cycle with fresh food and water.
In this study, a dog was anesthetized with sodium pentobarbital (60 mg per kg, intraperitoneal injection). The chest was excised and opened carefully. The whole pulmonary artery was removed from the chest, with particular attention to avoid the injury of adventitia. In one dog, the pulmonary artery was longitudinally cut along the blood flow direction from the orifice of the main pulmonary artery (the proximal portion of the main pulmonary artery) toward the right and left branches. Then, a vernier focusing camera was used to take pictures in order to identify whether there is a visible difference in the surface of the pulmonary artery between different segments.
With regard to five other dogs, connective tissue was manually dissected away from the pulmonary artery using fine microdissection scissors, under the guidance of stereomicroscope. During this procedure, great care was taken to avoid stripping off the adventitia and possible damage to the perivascular nerves. Vessels were stored at −70° for further staining.
Frozen vessels were processed in paraffin wax and fixed in 4% paraformaldehyde for 30 minutes and then incubated at 0.5% Pontamine Sky Blue (Sigma-Aldrich, St. Louis, Mo.) in phosphate-buffered saline (PBS) for 30 minutes to reduce background fluorescence. This was followed by 1 hour at room temperature in a blocking solution of 4% normal goat serum/0.3% Triton X-100 in PBS, then overnight at 4° C. in blocking solution containing an affinity-purified polyclonal antibody against tyrosine hydroxylase (Temecula, Calif.). Vessel segments were then washed in PBS and incubated for 1 hour with secondary antibody (Invitrogen, Carlsbad, Calif.), washed again and positioned on a glass slide. Preparations remained immersed in PBS during image acquisition to maintain hydration and preserve vessel morphology.
Based on previous studies, the sympathetical nerves were thought to be mainly localized at the proximal segment of the pulmonary artery. Thus the distal segment (5 mm in length) of the main pulmonary artery and proximal 5 mm segments of the right and left branches were selected for investigation in the present study. FIG. 6 schematically illustrates, not to scale, a 5 mm segment of the distal portion of the MPA and 5 mm long proximal portions of the LPA and RPA.
Multiple transverse slices (2 μm of thickness) of the vessels were cut at 1.6 mm intervals, and are identified in the description set forth below in accordance with the labels of FIG. 8. Care was taken to keep the luminal morphology of slices consistent with the vessel contour, in order to precisely position the location of nerves. The slices were examined by a pathologist.
Images of each slices were recorded (magnification 40× to 200×) using stereomicroscope (Olympus), and the numbers of total sympathetical nerves bundles (SPNDs) per level were manually calculated. Then all images were input to Image Analysis Software (Image-proplus 5.0), to calculate the minor radius (μm), major radius (μm) and total surface area (TSA, μm²×10³) area of axons.
After the pulmonary artery was removed from the chest of the dog, the pulmonary artery was repeatedly cleaned with saline to clean away all blood on the surface of the vessel. Then the whole vessel was cut along the direction from the proximal portion of the main pulmonary artery up through the trunk and into the right and left branches. The above-noted pictures (FIGS. 7A, 7B) showed that in the anterior wall of the main pulmonary artery, there was an obvious ridgy cystica close to the orifice of the left pulmonary artery. The site of the ridgy cystica felt rigid to the touch, compared to other areas of the pulmonary artery.
In the vicinity of the bifurcation portion of the pulmonary artery, segments 5-mm in length of the distal main pulmonary artery and the proximal portions of the right and left pulmonary arteries were studied. Four transverse slices (thickness 2 μm, 1.6-mm intervals) from each segment were prepared for analysis. Each slice (“level”) was divided into 4 subsegments in the right and left pulmonary arteries and 6 subsegments in the main pulmonary artery along the counterclockwise direction (FIG. 9).
Upon inspection of these samples, it was observed that more SPNDs were identified in the posterior wall in both the left and right pulmonary arteries (FIG. 10A). However the number of SPNDs was 1.6±0.2 in the 51 subsegment of the A5 level in the left pulmonary artery branch, significantly different from 1.2±0.2 in the 51 subsegment of level A1 in the right pulmonary artery (p=0.033). In contrast, more SPNDs were labeled in the anterior wall (S6) of the main pulmonary artery (FIG. 11) and decreased gradually from the levels A9 to A12.
The minor and major radius of sympathetical axons in the main pulmonary artery were 85±2 μm and 175±14 μm, compared to 65±3 μm and 105±12 μm in the left pulmonary artery or 51±2 μm and 86±8 μm in the right pulmonary artery, respectively, resulting in significant differences in surface area of axons between the main pulmonary artery and the LPA and RPA (FIG. 9).
Based on the results of the above-described observations, it has been determined that in canines, sympathetical nerves are distributed in higher concentrations along the anterior wall of the main pulmonary artery, then extend into the left and right pulmonary arteries, then extend upwardly and then toward the posterior walls of the left and right pulmonary arteries, as schematically represented in FIGS. 12 and 13.
Further, inspection of subsegment S6 in level A9 (FIG. 11) of the MPA (magnification 200×) revealed that a bundle or main bundle of sympathetical nerves originate from approximately the middle of the anterior wall of the distal portion of the main pulmonary artery and that this main bundle is bifurcated to the left and right pulmonary arteries.
This discovery provides a basis for more effective denervation of the pulmonary artery. For example, by selectively ablating only portions of the main pulmonary artery and the left and right pulmonary arteries, a higher success rate of denervation can be achieved with less unnecessary tissue damage. Such denervation can provide significant benefits in the treatment of diseases such as pulmonary hypertension, as described below.
With regard to the disease of pulmonary hypertension, it is well known that the lung receives axons from principal sympathetic neurons residing in the middle and inferior cervical and the first five thoracic ganglia (including the stellate ganglion), and the vasculature is the major sympathetic target in the lung. Sympathetic nerve stimulation increases pulmonary vascular resistance and decreases compliance, which is mediated by noradrenaline via a-adrenoreceptors, primarily of the a1-subtype.
Previous studies have confirmed the multiplicity of transmitters released from one nerve ending which might explain why pharmacological blockade of the “classical” transmitter alone does not effectively abolish the effects elicited by nerve stimulation. The present study explained above supports the concept that more successful sympathetical denervation along the pulmonary trunk can be enhanced at the proximal segments of the left and right pulmonary arteries rather than at the distal basal trunks. Further, percutaneous pulmonary denervation (PADN) has potential for decreasing pulmonary pressure and resistance induced by unilateral balloon occlusion in the interlobar artery. However, until now, there was a lack of data showing the distribution of sympathetical nerves in the pulmonary trunk. Thus, the accurate identification of the position of sympathetical nerves is important for performing a successful PADN procedure. In the present study, significantly larger bundles of sympathetical nerves were identified in the mid-anterior wall of the distal portion of the main pulmonary artery, which is bifurcated into the posterior wall of the left and right pulmonary arteries. These results imply that one or more ablation procedures, for example, by PADN, especially around the distal portion of the main pulmonary bifurcation and the proximal portions of the LPA and RPA are more likely to provide enhanced results and more successful denervation, as was suggested in the animal study noted above.
It is noted that sympathetic noradrenergic innervation density is highest at the large extra-pulmonary and hilar blood vessels, both arteries and veins and then decreases toward the periphery. This is in marked contrast to many other organs, in which the highest innervation density is found at the level of the smallest arterioles. Such distribution varies from species to species with regard to the extent to which the sympathetic noradrenergic axons reach into the lung. In guinea pigs, rabbits, sheep, cats, dogs, and humans, small arteries down to 50 μm in diameter are innervated, whereas in rats, mice, hedgehogs, and badgers, noradrenergic innervation stops close to the lung.
An extensive network of noradrenergic and NPY-containing fibers has been noted around pulmonary arteries of several species, but only a few studies used double-labeling techniques to evaluate the extent of colocalization. In the guinea pig, principally all noradrenergic fibers innervating pulmonary arteries and veins contain NPY and, in addition, dynorphin, a neuropeptide of the opioid family. In this aspect, pulmonary vascular innervation differs markedly from that of skin arteries in the same species, wherein three different combinations of noradrenaline, NPY, and dynorphin are used by sympathetic axons. Each of these populations is restricted to a specific segment of the arterial tree in the skin. Still, noradrenergic and NPY-containing fibers do not match 1:1 in the lung either, as there is a minor population of axons innervating guinea pig pulmonary arteries and veins that contains NPY plus vasoactive intestinal peptide (VIP) but not noradrenaline. It remains to be clarified whether this less-frequent fiber population represents the non-noradrenergic neurons projecting to the guinea pig lung or originates from other systems.
The present study explained above, which relied on the serial slicing at various levels through the pulmonary artery trunk demonstrates that larger bundles of nerves are more localized in the anterior wall of the main pulmonary artery and then bifurcate into the left and right pulmonary arteries along the posterior walls of the LPA and RPA. The above study was performed on canine anatomy.
One of the diseases that can be treated with the present methods and devices is idiopathic pulmonary arterial hypertension (IPAH). IPAH is characterized by elevations of mean pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR). The pathogenesis of IPAH was believed to be due to imbalance between locally produced vasodilators and vasoconstrictors. Recent studies have demonstrated that vascular wall remodeling also contributed to elevated PVR. The role of neural reflex in the mediation and development of IPAH has not been specifically investigated. In 1961, Osorio et al. reported the existence of a pulmo-pulmonary baroreceptor reflex that originates in the large pulmonary branches, with neither the afferent nor efferent fibers belonging to the vagus nerve. In 1980, these findings were again confirmed by Jurastch et al. and Baylen et al. More recently, the present animal study described above demonstrates that pulmonary arterial denervation (PADN) can reduce or completely abolish elevations of PAP induced by balloon occlusion at interlobar segments, but not at the basal trunk.
In a further phase of the present study, a human study was conducted. Prior to enrollment, all 21 patients received a diuretic (hydrochlorothiazide at a dose of 12.5 mg to 25 mg, once daily, and/or spironolactone at a dose of 20 mg to 40 mg, once daily) and beraprost (120 mg, 4 times daily) (Table 1), with either sildenafil (20 mg, 3 times a day) or bosentan (120 mg, twice daily) or digoxin (0.125 mg, once daily). Functional capacity of the patients was determined by a 6-minute walk test (6MWT), followed by an assessment of dyspnea using the Borg scale. The 6MWT was performed at 1 week, 1 month, 2 months, and 3 months following the PADN procedure. The WHO classification at rest and during exercise was recorded by a physician who was blinded to the study design.
Echocardiography was performed at 1 week, 1 month, 2 months, and 3 months following the procedure. Echocardiographic studies were done using a Vivid 7 ultrasound system with a standard imaging transducer (General Electric Co., Easton Turnpike, CT, US). All of the echocardiograms were performed and interpreted in the Medical University Echocardiographic Laboratory. All of the measurements were performed following the recommendations of the American Society of Echocardiography. Digital echocardiographic data that contained a minimum of 3 consecutive beats (or 5 beats in cases of atrial fibrillation) were acquired and stored. RV systolic pressure is equal to systolic PAP in the absence of pulmonary stenosis. Systolic PAP is equal to the sum of right atrial (RA) pressure and the RV to RA pressure gradient during systole. RA pressure was estimated based on the echocardiographic features of the inferior vena cava and assigned a standard value. The RV to RA pressure gradient was calculated as 4v_t ²using the modified Bernoulli equation, where v_tis the velocity of the tricuspid regurgitation jet in m/s. The mean PAP was estimated according to the velocity of the pulmonary regurgitation jet in m/s. The tricuspid excursion index (TEI) is defined as (A−B)/B, where A is the time interval between the end and the onset of tricuspid annular diastolic velocity, and B is the duration of tricuspid annular systolic velocity (or the RV ejection time). PA compliance for patients was calculated as stroke volume divided by pulse pressure (systolic PAP minus diastolic PAP).
Hemodynamic measurements and blood oxygen pressure/saturation determinations from the RA, RV, and PA were done prior to and immediately after the PADN procedure. These measurements were repeated at 24 hours and 3 months.
A 7F flow-directed Swan-Ganz catheter (131HF7, Baxter Healthcare Corp., Irvine, Calif.) was inserted into an internal jugular or subclavian vein. Measurements of resting RA pressure, RV pressure, systolic/diastolic/mean PAP, pulmonary artery occlusive pressure (PAOP), cardiac output (CO) (using thermodilution method), and mixed venous oxygen saturation were recorded. The PVR [=(mean PAP−PAOP)/CO] and trans-pulmonary gradient (TPG=mean PAP−PAOP) were then calculated. All of the measurements were recorded at the end of expiration. Five criteria were used to evaluate if a PAOP measurement was valid: (1) the PAOP was less than the diastolic PAP; (2) the tracing was comparable to the atrial pressure waveform; (3) the fluoroscopic image exhibited a stationary catheter following inflation; (4) free flow was present within the catheter (flush test); and (5) highly oxygenated blood (capillary) was obtained from the distal portion in the occlusion position. If the PAOP measurement was unreliable, the left ventricular end-diastolic pressure was then measured and used rather than the PAOP. The blood samples from the SVC and pulmonary artery were obtained for the measurements of oxygen pressure and saturation. Particularly significant reductions in systolic and mean PAP were achieved using temperatures above 50° C., drawing an electrical load of 8-10 W for a duration of 60-120 s, for example as shown in FIG. 14B.
The PADN procedure was performed with a dedicated 7.5 F multiple-function (temperature-sensor and ablation) catheter which comprised two parts, a catheter shaft 3 and handle 2 (FIG. 15A) which is an embodiment of the catheter illustrated in FIGS. 1-4. The catheter of FIG. 15A had a tapered (to 5 F) annular ring 4 with 10 pre-mounted electrodes 5 (E1-E10) each separated by 2 mm, however, other spacings can also be used. For purposes of the description set forth below, the electrodes 5 have been numbered, as shown in FIG. 15B, with the distal-most electrode 5 identified as electrode E1 and the proximal-most electrode 5 identified as electrode E10.
As described above with reference to FIGS. 1-4, the annular ring 4 or (“circular tip”) can be constructed so as to be biased into a circular shape, such as the circular shape illustrated in FIG. 15B and FIG. 1 to have any desired outer diameter. For example, in various embodiments, the annular ring 4 can be configured to be biased into a circular shape having an outer diameter of 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, or other diameters. Additionally, a kit containing the catheter of FIG. 1 can include a plurality of different annular rings 4 configured to be biased to a plurality of different outer diameters, such as those noted above, or other diameters.
A controller or “connect box” can be connected to the handle 2 of the catheter for providing ablation energy. For example, an ablation controller 100 can be configured to provide ablation energy to each of the electrodes E1-E10. Thus, in some embodiments, the controller 100 includes a selector knob 102 configured to allow a user to select activation of all the electrodes E1-E10, or selective actuation of individual ones of the electrodes E1-E10, one at a time.
Thus, in some embodiments, as illustrated in FIG. 15D, the selector knob 102 includes a position indicator 104 which, by rotating the knob 102 can be aligned with indicia corresponding to the electrodes E1-E10. In the illustrated embodiment, the indicia on the controller 100 includes the numbers 1-10 as well as a position identified as “OFF” and a position identified as “NULL.” In some embodiments, the connect cable 106 can include a plurality of wires, for example, ten wires which correspond to the lead wire 6 described above with reference to FIGS. 1-4, each one of which is individually connected to respective electrodes E1-E10.
The controller 100 can include a physical switch for creating an electrical connection between a source of RF energy and a desired one of the electrodes E1-E10. An electrode (not shown) can be directly connected to the knob 102 with additional contacts (not shown) disposed around the electrode at approximately the positions identified as 1 through 10 on the controller 100. Thus, rotation of the knob 102 will connect an internal electrode (not shown) with the contacts aligned with each one of the positions 1-10.
The controller 100 can be configured to provide the desired amount of ablation energy when a circuit is created by the alignment of the position indicator 104 with the corresponding position (1 through 10) on the controller 100 thereby delivering electrical energy to the selected one of the electrodes E1-E10 causing electrical energy to pass through the selected electrode 5 into any conductive material in contact with that selected electrode.
For example, during a PADN procedure, the electrodes E1-E10 can be in contact with an inner wall of the pulmonary artery trunk thereby allowing electrical energy from one of the electrodes E1-E10 to flow through the tissue of the inner wall of the pulmonary artery, described in greater detail below.
In some embodiments, with continued reference to FIG. 15D, the controller 100 can include a plurality of ports. For example, the controller 100 can include a catheter port 120, which can be configured for creating a fluidic connection to the annular ring for purposes of providing a flow of saline to the annular ring 4. The controller 100 can also include an RF port 122 configured to connect to any known radiofrequency generator used with regard to ablation procedures.
Additionally, the controller 100 can include an “ECG” port 124 configured for connection with standard ECG monitoring equipment. Thus, in some embodiments, the connect cable 106 can also include wires or conduits for transmitting data through the RF port 124.
Thus, in some configurations, the RF port 122 can be connected to a source of RF energy (not shown). One or more wires (not shown) can connect the port 122 to a contact on the end of an electrode connected to the selector knob 102. Additionally, the ten wires (not shown) can be configured to deliver RF electrical energy to the electrodes E1-E10 each of which can each be connected to contacts (not shown) associated with the selector positions 1-10 disposed around the periphery of the selector knob 102.
Thus, the electrode connected to the rotating selector knob 102 can be moved into contact with the electrical contacts associated with each of the positions 1-10 thereby creating a circuit connecting the electrical energy entering the controller 100 through the port 122 with the associated lead wire 6 for conducting electrical energy to the desired electrode E1-E10.
Thus, specifically, when the selector knob 102 is turned such that the position indicator 104 is aligned with position 1 on the controller 100, electrical energy from the RF port 122 is conducted through an associated lead wire 6 to the electrode E1. Aligning the indicator 104 with the other positions on the controller 100 would conduct electrical energy to the other electrodes associated with those other positions.
In some embodiments, a method for treating pulmonary hypertension can include a step of identifying the position of the pulmonary trunk of the patient using angiography. For example, baseline pulmonary artery angiography can be performed to identify the position of the pulmonary artery bifurcation from the main pulmonary artery into the left and right pulmonary arteries.
Additionally, the baseline pulmonary artery angiography can be used to determine the diameter of the portions of the pulmonary artery trunk upon which ablation is desired. As such, the appropriate diameter of the annular ring 4 can be determined based on the determined diameters of the pulmonary artery trunk noted above. For example, in some embodiments, an annular ring 4 having a biased diameter slightly larger than the diameters of the targeted anatomy can be used so as to enhance the contact between the electrodes 5 and the inner surface of the targeted anatomy. As such, for example, when the annular ring 4 is moved out of a sheath and allowed to expand into its biased circumferential configuration which has an outer diameter slightly larger than the inner diameter of the targeted portions of the pulmonary artery trunk, the bias of the annular ring 4 will assist in pressing the electrodes 5 into contact with the targeted tissue.
In some embodiments, with reference to FIGS. 16A-16H, a method can include a step of positioning a catheter in a pulmonary artery trunk. For example, an 8F long sheath can be inserted through the femoral vein and advanced to the main pulmonary artery, as shown in FIG. 16A. A PADN catheter, such as the catheter illustrated in FIG. 1 and FIGS. 15A-15E can be advanced along the sheath shown in FIG. 16A to the location of the pulmonary artery trunk.
With the distal end of the catheter maintained in place, the sheath can be withdrawn. It may be necessary to push on the catheter to maintain its position with the portion of the catheter forming the annular ring 4 held within the pulmonary artery trunk.
As the annular ring 4 is released from the sheath, as illustrated in FIG. 16B, the annular ring 4 can adopt the shape and diameter to which it is biased.
By slightly rotating and pushing the handle 2 in a clockwise direction, the annular ring 4 can be positioned at the proximal portion of the left pulmonary artery, such as at the ostium. In some embodiments, this initial position can be within a range of approximately five mm from the orifice of the left pulmonary artery or within a range of two millimeters, as illustrated in FIG. 16D.
By observing the orientation of the annular ring 4, the desired one or plurality of the electrodes E1-E10 can be selectively energized so as to perform ablation at the desired location on the interior surface of the left pulmonary artery. For example, in some embodiments, it may be more effective to selectively ablate the posterior wall of the left pulmonary artery, so as to achieve at least some sympathetic denervation of the left pulmonary artery and the proximal portion thereof, such as within two or five millimeters of the ostium of the left pulmonary artery.
The annular ring 4 can then be rotated, such as in the counterclockwise direction, by rotating and withdrawing the handle 2 in order to reposition the annular ring 4 into the distal portion of the main pulmonary artery such as at the bifurcation area. For example, in some embodiments, as illustrated in FIG. 16E, the annular ring 4 can be positioned within about 5 mm of the bifurcation in the pulmonary artery trunk. Optionally, the annular ring 4 can be positioned within about 5 mm of the bifurcation in the pulmonary artery trunk. Ablation can then be performed using the desired one or plurality of the electrodes E1-E10.
For example, positioned as such, the selected one or plurality of electrodes E1-E10 can be energized to achieve the desired sympathetic denervation of the distal portion of the main pulmonary artery. In some embodiments, it may be desirable to perform ablation preferentially on the anterior wall of the distal portion of the main pulmonary artery.
Additionally, further rotating and pushing the handle 2 can be performed until the annular ring 4 is positioned in the proximal portion of the right pulmonary artery, such as at the ostium. In some embodiments, this position can be within 5 mm of the ostium of the right pulmonary artery. Further, in some embodiments, this position can be within 2 mm of the ostium of the right pulmonary artery.
With the annular ring 4 positioned as such, the desired one or plurality of electrodes E1-E10 can be energized so as to achieve at least some sympathetic denervation in the proximal portion of the right pulmonary artery. For example, in some embodiments, it may be beneficial to focus on the posterior wall of the right pulmonary artery.
In some embodiments, a method for treating pulmonary hypertension can also include a step of confirming the appropriate contact between the electrodes E1-E10 and the endovascular surface corresponding to the three positions noted above. For example, in some embodiments, such confirmation can be performed by determining if there is strong manual resistance when attempting to rotate the handle 2. Additionally, it can be determined if the annular ring 4 cannot be advanced distally, resulting in the deformation of the catheter as illustrated in FIG. 16G or if there is ease in withdrawing proximally, resulting in the deformation of the catheter illustrated in 16H. Additionally, confirmation can be performed using angiographic confirmation.
When the appropriate contact has been confirmed with the annular ring 4 is positioned as desired such as in the positions illustrated in FIGS. 16D, 16E and 16F, at least one of the electrodes E1-E10 can be energized so as to perform ablation. For example, in some embodiments, a method for treating pulmonary hypertension can include the sequential energization of each of the electrodes E1-E10.
Additionally, in some embodiments, a method for treating pulmonary hypertension or for performing pulmonary denervation can include the step of repositioning the annular ring 4 so as to shift the location of the electrodes E1-E10 and then repeating energization of all of the electrodes E1-E10. As such, a more complete denervation of the entire inner surface of the associated vessel can be achieved.
In some embodiments, any desired energy levels or temperatures can be used for performing ablation using the electrodes E1-E10 noted above. For example, in some embodiments, ablation can be performed at temperatures above 50° C., drawing an electrical load of 8-10 W for a duration of 60-120 s. Additionally, in some embodiments, a method of treatment of pulmonary hypertension or a method of sympathetic denervation of the pulmonary artery can be performed with a patient anesthetized but conscious. Thus, any ablation procedure can be stopped if the patient complained of intolerable chest pain.
In some embodiments, EKG and hemodynamic pressure can be monitored and continuously recorded throughout the method. In a study performed in accordance with the description noted above, success was defined as a reduction in the mean PAP≧10 mmHg (as measured by the Swan-Ganz catheter). During the study, there were no complications. Additionally, the patients were monitored in the CCU for at least 24 hours after the PADN procedure was performed.
For example, in some embodiments of methods disclosed herein, a dedicated 7.5 F triple-function catheter (A) can be used, which can include a tapered (to 5F) annular ring 4 with 10 electrodes (each has 0.75 mm electrode-width and is separated by 2-mm, B), pre-mounted. Electrodes are connected with a connect-cable 106 and a connect-box/controller 100. There are 10 positions of the knob 102 (FIG. 15D) on the surface of controller 100, and each is associated with one of the electrodes E1-E10 on the annular ring 4 of the ablation catheter. Sequential ablation can be performed by turning the knob 102 as desired after the whole system is set up.
In some embodiments of methods for performing pulmonary artery denervation or methods for treating primary PAH ablation of the distal portion of the main pulmonary artery can be performed preferentially on the anterior side thereof. For example, in some embodiments, as shown in FIG. 17A, ablation can be performed at the positions identified as M1, M2, M3, M4, and M5.
With a continued reference to FIG. 17A, the position identified as M1 is at the “6 o'clock” position in the distal portion of the main pulmonary artery. The positions identified as M3 and M5 are the sites where the anterior wall of the main pulmonary artery connects to the left and right pulmonary arteries, respectively. The positions identified as M2 and M4 correspond to the “5 o'clock” and the “7 o'clock” positions on the anterior side of the distal portion of the main pulmonary artery.
In some embodiments, with reference to FIG. 17B, sympathetic denervation in the left and right pulmonary arteries can be performed, preferentially, at approximately the middle of the anterior wall of the proximal portion of the left pulmonary artery (L1) and at approximately the upper conjunctive site of the distal portion of the main pulmonary artery in the left pulmonary artery (L2).
Similarly, during a method of performing pulmonary denervation of the right pulmonary artery, ablation can be preferentially performed at a point approximately at the middle anterior wall of the proximal portion of the right pulmonary artery (L3) and at approximately the upper conjunctive site of the distal portion of the main pulmonary artery and the right pulmonary artery (L4).
In some embodiments, sympathetic denervation can be performed, for example, for treatment of pulmonary hypertension associated with a pulmonary duct artery (PDA). For example, a pulmonary duct artery usually connects the descending aorta with the left pulmonary artery, as shown in FIG. 4A. With this anatomy, the left pulmonary artery can be significantly larger than the right pulmonary artery.
Thus, in some embodiments, ablation can be performed at a position proximal to connection between the left pulmonary artery and the pulmonary duct artery, identified as “Level A” in FIG. 18A. Thus, using the technique described above with reference to FIGS. 16A-16H, the annular ring 4 can be positioned at a position corresponding to Level A of FIG. 18B. Ablation can then be performed around part or all of the interior wall of the left pulmonary artery at that location.
In some embodiments, ablation can be preferentially performed on the anterior wall of the left pulmonary artery proximal to the proximal end of the pulmonary duct artery. For example, ablation can be performed at four or more sites, such as those identified as sites L1, L2, L3, L4. As illustrated in FIG. 18B, position L1 corresponds to “12 o'clock”, position L2 corresponds to “2 o'clock”, position L3 corresponds to “3 o'clock”, and position L4 corresponds to “6 o'clock.” Other positions can also be used.
Additionally, in some embodiments, ablation can also be performed at positions M1-M5 illustrated in FIG. 17A and positions L1-L4 of FIG. 17B.
In some embodiments, a method for sympathetic denervation can be used for treating pulmonary hypertension resulting from unilateral chronic thrombotic embolism. For example, a patient suffering from unilateral CTEH can have an occluded right pulmonary artery. For example, in some patients, the RPA can be significantly enlarged as illustrated on the left side of FIG. 19A. Similarly to the method described above with reference to FIG. 18B, ablation can be performed at the position identified as “Level B” in FIG. 19A. Ablation can be performed at one or a plurality of locations along the inner surface of the right pulmonary artery at the position of Level B, or other positions. Additionally, ablation can be preferentially performed on a plurality of points along the anterior wall of the right pulmonary artery at the position of Level B.
For example, the positions identified in FIG. 20B can be considered such as position L1 corresponding to “12 o'clock”, position L2 corresponding to “2 o'clock”, position L3 corresponding to “3 o'clock”, and position L4 corresponding to “6 o'clock.” Additionally, in some embodiments, ablation can also be performed at positions M1-M5 illustrated in FIG. 17A and positions L1 and L2 illustrated in FIG. 17B.
As used herein, the term “animal” is intended to include human beings and other animals such canines, other mammals, etc. As used herein, the terms “live”, “living”, “live animal” are intended to exclude methods of euthanasia, surgery performed on dead animals including dissection and autopsies, or other techniques for disposing of dead bodies.
While at least a plurality of different embodiments are disclosed herein, it should be appreciated that a vast number of variations exist. It should also be appreciated that the embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiments. It should be understood that various changes can be made in the function and arrangement of elements or steps without departing from the scope defined by the claims, which includes known equivalents and foreseeable equivalents at the time of filing this patent application.

Claims

What is claimed is:

1. A pulmonary artery ablation catheter, comprising:

a control handle;

a catheter body being hollow and comprising a cavity arranged in the catheter body, the catheter body extending along a catheter body direction;

a tissue-contacting ablation portion disposed at a distal end of the catheter body, the tissue-contacting ablation portion being flexible so as to be deformable between a first retracted configuration in which the tissue-contacting ablation portion extends along the catheter body direction and a second deployed configuration in which the tissue-contacting ablation portion extends along an annular ring shape, the tissue-contacting ablation portion being biased into the annular ring shape oriented transverse to the catheter body extending direction; and

at least a first ablation device disposed on the tissue-contacting ablation portion in a position such that when the tissue-contacting ablation portion is in the second deployed configuration, the first ablation device faces a radially outward orientation relative to the annular ring shape of the tissue-contacting ablation portion.

2. The pulmonary artery ablation catheter according to claim 1, wherein the tissue-contacting ablation portion is biased to an annular ring shape having a diameter between 25 mm and 45 mm.

3. The pulmonary artery ablation catheter according to claim 1, wherein the tissue-contacting ablation portion is biased to an annular ring shape having a diameter in the range of 12 mm to 40 mm.

4. The pulmonary artery ablation catheter according to claim 1, wherein the tissue-contacting ablation portion has a length sized and is biased to an annular ring shape that is less than a full circle.

5. The pulmonary artery ablation catheter according to claim 1, wherein one end of the catheter body is flexible, and the flexible end is connected to the annular ring, and wherein the other end of the catheter body is connected to the control handle.

6. The pulmonary artery ablation catheter according to claim 5, wherein one end of the pull wire is connected to the flexible end, and the other end of the pull wire is connected to an adjustment apparatus on the control handle, the adjustment apparatus being configured to adjust the tension of the pull wire to change a curvature of the flexible end.

7. The pulmonary artery ablation catheter according to claim 1, additionally comprising a shape memory wire disposed in the tissue-contacting ablation portion and configured to provide the bias of the tissue-contacting ablation portion into the annular ring shape.

8. The pulmonary artery ablation catheter according to claim 1, wherein the tissue-contacting ablation portion comprises an electrode group including a plurality of electrodes, and each electrode of the electrode group is connected to a lead wire a temperature sensing wire.

9. The pulmonary artery ablation catheter according to claim 8, wherein the lead wire and the temperature sensing wire go through the catheter body and are electrically connected to the control handle.

10. The pulmonary artery ablation catheter according to claim 1, additionally comprising an infusion tube arranged in the cavity of the catheter body and a through hole is arranged on the at least one ablation device, the infusion tube extending through the tissue-contacting ablation portion connected to the at least one ablation device such that transfused fluid flows out from the through hole.

11. The pulmonary artery ablation catheter according to claim 1, additionally comprising at least a plurality of ablation devices, wherein the ablation devices comprise a material selected from the group consisted of platinum-iridium alloy, gold, stainless steel and nickel alloy, a diameter in the range of 1.3-2.0 mm, a length in the range of 1.2-4 mm and an edge space between adjacent ablation devices in the range of 0.5-10 mm.

12. The pulmonary artery ablation catheter according to claim 1, wherein the tissue-contacting ablation portion includes a counterbore, an inner diameter of the counterbore fits around an outer diameter of a root of the tissue-contacting ablation portion, the root being inserted into and fixed in the counterbore.

13. The pulmonary artery ablation catheter according to claim 1, wherein the tissue-contacting ablation portion includes a groove, a connector is disposed in the groove, wherein one end of the connector is connected to a pull wire and the other end of the connector is connected to shape memory wire disposed in the tissue-contacting ablation portion.

14. The pulmonary artery ablation catheter according to claim 1, wherein the tissue-contacting ablation portion includes shape memory wire comprising shape memory alloy selected from the group consisted of nickel titanium alloy, stainless steel and titanium, with a diameter in the range of 0.25-0.5 mm, the diameter of the annular ring being in the range of 12-40 mm.

15. The multi-pole synchronous pulmonary artery radiofrequency ablation catheter according to claim 1, wherein the flexible end of the catheter body is made of medical polymer materials with a length in the range of 30-80 mm.

16. The multi-pole synchronous pulmonary artery radiofrequency ablation catheter according to claim 1, wherein the connector is connected with a UV-curing adhesive.

17. The multi-pole synchronous pulmonary artery radiofrequency ablation catheter according to claim 1, wherein the joint between the flexible end of the catheter body and the annular ring is sealed.

18. The multi-pole synchronous pulmonary artery radiofrequency ablation catheter according to claim 1, wherein the pull wire is made of stainless steel or nickel-titanium alloy, the pull wire including a coil spring, the coil spring includes a spring sleeve made of a polyimide material.

19. The multi-pole synchronous pulmonary artery radiofrequency ablation catheter according to claim 1, wherein the shape memory wire is configured to bias the annular ring into a circumferential configuration with exposed surfaces of the electrodes facing radially outwardly.

20. A pulmonary artery ablation catheter, comprising:

a catheter body including a handle;

a lumen member having a proximal end connected to the catheter body and a distal end;

an ablation device assembly having a proximal end connected to the distal end of the lumen member, the ablation device assembly comprising a longitudinally extending flexible lumen member and a plurality of ablation devices disposed along the flexible lumen member, each ablation device having a surface exposed at an outer surface of the flexible lumen member, the flexible lumen member being biased into a circumferentially extending annular ring shape wherein exposed surfaces of the electrodes face a radially outward direction when the flexible lumen member is in the circumferentially extending configuration.

21. The catheter according to claim 20, additionally comprising an electrical connection having a proximal portion in the handle and extending from the handle to each of the plurality ablation devices and configured to allow energy applied to the proximal portion of the electrical connection to be independently applied to each of the ablation devices.

22. The catheter according to claim 21, wherein the ablation devices are separated and electrically isolated from each other.

23. The catheter according to claim 22, wherein the electrical connection comprises a plurality of electrical wires connected to the plurality of ablation devices, respectively.

24. The catheter according to claim 20, wherein each ablation device further comprises a plurality of through holes and wherein the flexible lumen member includes at least one lumen extending from the proximal end of the flexible lumen member to the through holes on each of the ablation devices thereby forming a fluidic connection from the proximal portion of the flexible lumen member to the through holes.

25. The catheter according to claim 20, wherein the tissue-contacting ablation portion is biased to an annular ring shape having a diameter between 25 mm and 45 mm.

26. The catheter according to claim 20, wherein the tissue-contacting ablation portion is biased to an annular ring shape having a diameter in the range of 12 mm to 40 mm.

27. The catheter according to claim 26, wherein the tissue-contacting ablation portion has a length sized and is biased to an annular ring shape that is less than a full circle.