US20080249504A1

US20080249504A1 - Instrument port

Info

Publication number: US20080249504A1
Application number: US12/006,967
Authority: US
Inventors: Omar M. Lattouf; Dirk Hoyns; Larry Hall; Amin Rahme
Original assignee: Transcardiac Therapeutics Inc
Current assignee: Transcardiac Therapeutics Inc
Priority date: 2007-04-06
Filing date: 2008-01-08
Publication date: 2008-10-09
Also published as: US20130253641A1; US20120203072A1; US10456260B2; US20190209325A1; US20180263659A1; US9999442B2

Abstract

Instrument port for allowing access to the interior of the heart or other organ while minimizing blood loss.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No. 11/784,385, filed on Apr. 6, 2007. The entire content of the prior filed application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention is in the field of surgery, more specifically in the field of minimally invasive methods for surgical procedures. In particular, the invention is directed to devices that facilitate minimally invasive access to and treatments on an area of the body or an organ. More particularly, the device is a port that facilitates access for a medical instrument to an area of the body or the inside of an organ.
While the device is described herein particularly as a device to facilitate access for an instrument to the interior of the heart, it should be understood that the device can be used elsewhere in the body, to facilitate access to a variety of areas and organs.
Medical procedures on the heart can be performed inside the heart (endocardial) and on the outside of the heart (epicardial). Endocardial procedures require access to the interior of the heart, which can be accomplished percutaneously through the vasculature or directly, through the patient's chest and heart wall.
For percutaneous access, a catheter is typically inserted at the femoral or carotid artery and threaded into the heart via the vasculature. Travel of the catheter is monitored using a fluoroscope. Percutaneous treatment has several issues that make it less than desirable. For one thing, the catheters and tools that are used for percutaneous cardiac procedures are limited in size because they must be threaded through the vasculature into the heart. When a guide catheter is used, only tools that are smaller than the guide catheter can be threaded through the catheter to the intended site of use. In cases where more than one type of tool is used, each tool must be threaded separately, adding to the length of the process.
Maneuverability of a catheter which is threaded such a long distance is limited, which means that it is difficult and sometimes impossible to locate the working end of the catheter exactly at the area in the heart where treatment is needed. This also adds to the total length of the procedure. Another issue with percutaneous access can be various vascular complications such as bleeding, dissection, and rupture of a blood vessel. Moreover, some areas of the heart are simply difficult to access percutaneously.
For direct access to the interior of the heart, physicians have traditionally used open heart surgical procedures. This involves a gross thoracotomy, usually in the form of a median sternotomy, to gain access to the thoracic cavity. A saw or other cutting instrument is used to cut the sternum longitudinally, allowing the rib cage to be spread apart. A large opening into the thoracic cavity is thus created, through which the surgeon can directly visualize and operate upon the heart. Of course, such an invasive procedure has consequences, such as typically an extended hospital stay and an increased risk of complications and pain.
Once the surgeon has accessed the thoracic cavity, and the exterior of the heart, he must gain access to the interior of the heart for endocardiac procedures. Opening up the heart surgically can only be done after placing the heart under cardioplegic arrest and maintaining circulation using cardiopulmonary bypass. Stopping the heart invites serious complications.
To avoid cardiac bypass, the surgeon must have a way to penetrate the heart wall with an instrument without losing a tremendous amount of blood. A hemostatic seal must be created around the instrument passed through the wall. One way to create a hemostatic seal is by using a purse-string suture around the instrument inserted through the heart wall. However, purse-string sutures are not always effective and do not easily allow the insertion of more than one instrument through a single incision.
From the above discussion it is apparent that there is a need for devices and methods to access the inside of the heart other than percutaneously and directly via open heart surgery. There is a need for methods and devices to access the interior of the heart minimally invasively. There is further a need for devices that allow instruments that have already been developed for percutaneous use to be used in minimally invasive endocardiac procedures.
Accordingly, to avoid the disadvantages of both open heart surgery and percutaneous access, the present invention provides a method for minimally invasive access to the interior of the heart (and to other areas and organs of the body). An area of the heart that is preferably accessed is the ventricular apex of the heart, which is the rounded inferior extremity of the heart formed by the left and right ventricles. In normal healthy humans it generally lies beneath the fifth left intercostal space from the mid-sternal line.
Access to the interior of the heart via the apex (trans-apical access) is taught in U.S. Pat. No. 6,978,176 to Lattouf. This patent is primarily directed to mitral valve repair but the method taught therein is described as being useful for other procedures such as ablation.
U.S. patent application Ser. No. 11/784,385 to Lattouf et al., filed on Apr. 6, 2007, teaches an endocardiac access system comprising an instrument port and an instrument guide. The port of the present invention contains advantageous features not taught in the prior application.

SUMMARY OF THE INVENTION

The present invention is directed to devices and methods for accessing the interior of the heart without having to stop the heart from beating and while minimizing blood loss. The devices and methods are useful for performing endocardiac treatments. The methods rely upon access to the interior of the heart through the heart wall using an instrument port.
In a preferred method, the instrument port is implanted into the heart wall using a minimally invasive opening in the chest wall. However, the port could also be installed after a more invasive procedure to open the chest wall and access the heart, such as a gross thoracotomy. The instrument port is installed in the heart wall and allows passage of instruments therethrough into a heart chamber. The port is anchored by a sealing device which also serves to reduce blood loss from the heart.
The invention will become more apparent from the following detailed description and accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a patient's chest, partially illustrating the patient's heart with part of the heart wall removed to expose the left ventricular and atrium chambers and showing the device of the invention in position.

FIG. 2 shows one embodiment of an instrument port of the invention.

FIG. 3 shows another embodiment of the instrument port.

FIG. 4 shows another embodiment of the instrument port.

FIG. 5 shows another embodiment of the instrument port.

DETAILED DESCRIPTION OF THE INVENTION

The device allows a physician to gain access to the interior of the heart, preferably in a minimally invasive manner, so that he or she can perform a medical procedure therein. The instrument port is designed to be temporarily implanted through the heart wall, to allow passage of one or more instruments into the heart while minimizing blood loss out of the heart.
FIG. 1 illustrates the device 10 as used to facilitate delivery of an ablation catheter into the left atrium of a patient's heart. It should be understood that although the instrument port is shown inserted through the apex of the left ventricle to facilitate access to the left atrium, it can be inserted through any area of the heart wall for access to any area of the heart. The port can also be used in other areas of the body. In addition, although the instrument port 10 is shown for delivery of an ablation catheter it can be used with a wide variety of instruments and in a wide variety of procedures.
As described in more detail below, the instrument port 10 is preferably installed into the heart wall through a minimally invasive opening made in the patient's chest. In FIG. 1, this minimally invasive opening is maintained using a chest trocar 12. However the instrument port is not limited to use in minimally invasive treatments and could be used after a more invasive opening is made in the patient's chest. After the patient's chest is opened and the heart is exposed, a series of dilators and one or more guidewires can be used to form an opening through the heart wall and insert the instrument port 10 through the heart wall, at the apex 14 of the left ventricle 16 as shown in FIG. 1.
After the instrument port 10 is inserted through the heart wall, the sealing devices are activated (described below in detail), anchoring the port 10 in place and sealing the opening to reduce blood loss therethrough. Any of a number of instruments can then be inserted through the port and into the heart.
As shown in FIG. 1, an ablation catheter 18 is inserted through the instrument port 10, into the left ventricle 16, past the mitral valve 20, and into the left atrium 22. The tip of ablation catheter 18 is thus placed in the left atrium.
If desired, the ablation catheter 18, or any other tool, can be used with an instrument guide, such as that described in application Ser. No. 11/784,385. The instrument guide can help deliver the instrument to the desired area.
FIG. 2 illustrates the instrument port 10 in greater detail as inserted through a tissue wall 24. Instrument port 10 desirably has a cylindrical tubular body 30 with a heart wall portion 32 that generally is the width of the tissue wall 24. The width of the heart wall portion can be varied, as discussed further below.
Sealing devices are located on either side of the heart wall portion 32. In the embodiment shown the sealing devices are two balloons, one distal balloon 36 on the inside of the tissue wall 24 and one proximal balloon 34 on the outside of the tissue wall 24. The sealing devices may however be a single balloon crimped in the middle, where the crimped part of the balloon is generally on the heart wall portion 32 and a portion of the balloon extends from either side of the wall portion 32 and the tissue wall 24 when the port is in place. In another embodiment the sealing device of the port is a single balloon on the side of the port on the inside of the heart wall. Instead of a balloon sealing device on the outer side of the heart wall portion, the port can have a flange or other structure that serves to stabilize the device. In any case the sealing devices are desirably expandable balloons, wherein the inside balloon 36 is flat or pancake shaped and the outer balloon 34 may also be pancake shaped or more desirably is substantially spherical. This embodiment is particularly advantageous for use in the heart, and other places where interior space is limited, since the flat shaped balloon 36 requires less space. The flat balloon 36 also provides better sealing against the tissue wall 24 to prevent blood from leaving the heart chamber. The sealing devices may also serve to hold the port in place within the heart wall.
In a preferred embodiment, the interior balloon 36 ranges in size in diameter from about 0.5 to 2.5 cm in diameter and in thickness from about 0.1 to 1.5 cm, although it may be smaller or larger, depending upon the application. The exterior balloon ranges in size up to about 3 cm in diameter. The balloons are desirably made of polyurethane, although they may be made of any suitable biocompatible material. They can be fastened to the port body by any suitable means. For example, one method of fastening the balloons to the port body is using an adhesive.
The instrument port cylindrical body 30 desirably measures from about 5 to 25 cm in length. The distal tip 40 of the port, measuring about 0.5 to 1 cm in length, is desirably tapered and is radiopaque for visualization.
Wall portion 32 of the instrument port 10 is defined by the sealing devices on either side, the balloons 34 and 36 as shown in FIG. 2. The width of wall portion 32 is desirably about the same as the thickness of the wall through which the port 10 is inserted. In most cases this will be from about 5 to 40 mm. The instrument port can have a wall portion of a set length or, in alternate embodiments, the instrument port has a variable length wall portion. Designs for instrument ports 10 having variable length wall portions are discussed below.
As shown in FIG. 2, the instrument port 10 has three lumens, one central instrument lumen 42, and one for inflating each of the balloons 34, 36. In other embodiments, the port 10 could have more or less lumens. For example, a single lumen could be used to inflate both balloons 34, 36. As another example, the port 10 could have more than one delivery lumen, such as one lumen for a tool and one lumen for a viewing scope, or a second tool.
The outer diameter of the instrument port 10 is desirably from about 1 to 20 mm and the inner diameter of the instrument lumen is desirably about 1 to 15 mm. This allows passage of an instrument guide or instrument through the port of up to 15 mm (45 Fr). Various sized ports may be desirable for ports employed for different purposes. The port 10 includes a one way valve (not shown) in the inner lumen so that blood is prevented from exiting the heart but an instrument can be inserted through the inner lumen. The valve is desirably a hemostatic valve, such as a duck-bill valve, and is desirably made of silicon although other types of valves and materials can be used.
The instrument port is desirably made of polyether block amides known as PEBAX® polymers or other plasticizer-free thermoplastic elastomers.
The balloon lumens 44, 46 lead to balloons 34, 36 respectively, and to inflation tubes 54, 56, respectively. A manifold 50 serves as a comfortable grip for the port 10 and also organizes the inflation tubes 54, 56. The manifold desirably includes raised markings 64, 66, that indicate which balloon is inflated with the corresponding inflation tube. This safety feature is shown in FIG. 2 as two barbell shaped markings, wherein (for the raised marking 64) one of the barbell ends 68 is a raised and filled (colored) circle and the other barbell end 70 is a non raised open (non colored or filled) circle. The colors of the raised barbell ends correspond to the colors of the fittings 58, 60, respectively.
In addition, the manifold may have a raised bump 72 on one side, to indicate to the handler which balloon he is inflating. This bump is shown in FIG. 2 on the side of the manifold holding the inflation tube 56 for the inside balloon 36. The raised markings 64, 66 and raised bump 72 are safety features, providing the surgeon with an indication of which inflation tube leads to which balloon.
As stated, the balloons 34, 36 are filled via inflation tubes 54, 56 via lumens 44, 46. The embodiment is shown with separate inflation lines for each balloon but they could alternatively be filed via the same inflation port.
Cylindrical body 30 is held by manifold 50 and extends to the proximal end of manifold 50. A purge valve 74 on the proximal end of the port 10 is in fluid communication with the instrument lumen 42. This purge valve 74 can be used to flush the port 10 with saline or blood prior to insertion, or to allow air removal from the port 10 during insertion. Purge valve 74 could also be used for infusion of saline, blood, or active agents during the use of the port for the medical procedure, if desired.
Various alternative designs for the instrument port are described below.
FIGS. 3-7 illustrate alternate embodiments of the instrument port. As discussed above, the length of the wall portion is desirably about the same as the thickness of the wall through which the port is inserted. The thickness of the heart wall varies from about 5 to 40 mm so an instrument port having a variable length wall portion would be useful.
In FIG. 3, the instrument port 80 is two cylindrical tube pieces assembled in a slidable coaxial relationship. An inner piece 82 includes a first, distal, balloon 84. An outer piece 86 includes a second, proximal, balloon 88. The pieces 82 and 86 are assembled in a coaxial sliding assembly so that the distance between the balloons 84 and 88 can be varied. A locking nut 89 on the proximal end of the second, outer piece 86 keeps the tubes 82 and 86 from sliding once they are in position. Inflation ports 90 and 92 are used to fill the balloons 88 and 84, respectively. Balloon 84 is flat, as described above for balloon 36 of FIG. 2.
Rather than the internal one-way valve as shown in FIG. 2 above, this embodiment has a hemostatic valve 94 on the proximal tip of the first inner piece 82. Either arrangement is possible for all embodiments described herein. Preferably both pieces 82 and 86 are long enough to extend out of the patient's chest so they can be easily manipulated.
FIG. 4 illustrates an instrument port 100 having a cylindrical body portion 102 and a single balloon 104. The balloon 104 is constrained with a spacer 106 of a certain length. The spacer 106 length approximates the heart wall thickness where the port 100 is to be installed. The spacer can be slid over one end of the port or may be made of a material that allows it to be spread open so that it can be placed on the port and then contracted once it is in place. The spacer 106 may optionally be crimped or glued in place or otherwise attached to the balloon. The balloon is designed so that the distal end 108 of the balloon is flat. A similar port (not shown) has two balloons and uses a spacer to define a set distance between the balloons when they are inflated.
In the embodiment shown in FIG. 5, the spacer 116 includes a stop 118 on the proximal end thereof, so that as the port is inserted into the heart wall it will only be inserted as far as the stop 118. A stop can be incorporated into any of the instrument ports described in this application. The distal end 120 of the balloon 122 is again flat or pancake shaped.
The various components of the ports described here can be interchanged. For example, any of the ports can include a stop, to prevent the port from being inserted all the way through the heart wall. Any of the ports can include a spacer to define the space between the balloons, or between a balloon and a stop. Any of the ports can have a single balloon, wherein the inside or distal end of the balloon is flat shaped.
Any of the instrument ports described in this application can have one or more markers placed thereon so that they are visible by visualization means. For example, markers can be placed on either side of either or both balloons so that the physician can “see” where the port is in relation to the heart wall. Another way to promote visualization is using contrast agent in the balloon inflation media.
The procedure for using the port is described in particular with respect to the embodiment of FIGS. 1 and 2. The procedure generally includes first gaining access to the patient's chest cavity through a small opening made in the patient's chest, preferably though an intercostal space between two of the patient's ribs. Such accessing can be effected thorocoscopically through an intercostal space between the patient's ribs by minimally invasive procedures wherein a trocar 12 or other suitable device is placed within the small opening made in the patient's chest.
To the extent required, the patient's deflated lung is moved out of the way, and then the pericardium on the patient's heart wall is removed to expose a region of the epicardium. The patient's heart wall is pierced at the exposed epicardial location to provide a passageway through the heart wall to a heart cavity such as the left ventricle. For the purposes of the discussion herein, the passageway is formed through a region of the heart wall at or near the apex of the patient's heart. A suitable piercing element includes a 14 gauge needle. A guide wire is advanced through the inner lumen of the needle into the heart chamber to the area of the heart to be treated. The penetrating needle may then be removed leaving the guide wire in place.
A sequence of progressively larger dilators can be inserted through the heart wall sequentially over the guidewire in predilation until the hole formed in the heart wall is large enough to accept the instrument port 10. The instrument port 10 (with the balloons deflated and properly folded) is then inserted over the last dilator. The dilator is removed and the balloons are inflated, holding the port in place and preventing or greatly reducing blood seepage from the heart.
Other methods of installing the instrument port 10 can be used. For example, a sheath can be placed over the last dilator, the dilator removed and then the port inserted into place through the sheath.
Various procedures can be performed using the port, such as the mitral valve repair procedure discussed in U.S. Pat. No. 6,978,176 to Lattouf. Endocardial ablation can be performed, using, for example, percutaneous ablation catheters sold by various companies that utilize different energy sources such as radiofrequency, cryogenesis, ultrasound, microwave, radiation (beta source), or laser. For example, St. Jude Medical sells the Epicor technology that utilizes high intensity focused ultrasound (HIFU). Cryocath Inc. markets a circular cryocatheter called the Artic Circler. Cardima sells the Revelation Helix.
Once the procedure is complete, the instruments are removed, the port is removed and the heart wall opening is sutured. A plug can be inserted into the heart wall opening if desired.
Modifications and variations of the present invention will be apparent to those skilled in the art from the forgoing detailed description. All modifications and variations are intended to be encompassed by the following claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety.

Claims

1. A transcardiac instrument port for placement in a heart wall to allow passage into a chamber of the heart, comprising:

a cylindrical body portion defining a lumen and having an outer surface, a heart wall portion, and distal and proximal ends;

a valve associated with the lumen that allows passage of an instrument through the lumen but minimizes flow of blood out of the heart through the lumen; and

a sealing device on the body portion outer surface that minimizes blood flow from out of the heart around the outside of the port;

wherein the sealing device includes at least one inflatable distal balloon, arranged for placement on the interior side of the heart wall;

wherein the balloon is pancake shaped.

2. The port of claim 1, wherein the sealing device includes a second inflatable proximal balloon, arranged for placement on the outer side of the heart wall.

3. The port of claim 2, wherein the distal and proximal balloons are separate balloons.

4. The port of claim 2, wherein the distal and proximal balloons are portions of a single balloon, separated by a spacer.

5. The port of claim 4, wherein the spacer has a length that approximates the width of the heart wall where the instrument port is to be inserted.

6. The port of claim 2, further having a manifold that holds the cylindrical body portion and inflation tubes leading to the distal and proximal balloons, wherein the manifold includes markings that indicate which inflation tube inflates which balloon.

7. The port of claim 1, wherein the cylindrical body portion comprises two cylindrical pieces in a slidable coaxial relationship.

8. The port of claim 1, comprising a stop on the proximal side of the heart wall portion that stops movement of the port through the heart wall into the heart chamber.