Patent Application
20120095334
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to methods and devices for controlling inflation of an expandable member in a lumen within the body during minimally invasive surgical interventions.
Minimally invasive surgery provides several advantages over conventional surgical procedures, including reduced recovery time, reduced surgically-induced trauma, and reduced post-surgical pain. Moreover, the expertise of surgeons performing minimally invasive surgery has increased significantly since the introduction of such techniques in the 1980s. As a result, substantial focus has been paid over the past twenty years to devices and methods for facilitating and improving minimally invasive surgical procedures.
One area in which there remains a need for substantial improvement is pre-surgical assessment of treatment locations intended to be subjected to a minimally invasive surgical procedure. For example, when a surgical procedure is to be performed at a treatment location within the body of a patient, it would frequently be beneficial for the surgeon to assess the shape, size, topography, compliance, and other physical properties of the treatment location and use the information to control devices performing procedures within a body lumen or within a hollow portion of an organ located within the body of the patient.
A particular portion of the anatomy for which complete and accurate physical assessment and control of treatment would be beneficial are the coronary valves. Diseases and other disorders of heart valves affect the proper flow of blood from the heart. Two categories of heart valve disease are stenosis and incompetence. Stenosis refers to a failure of the valve to open fully, due to stiffened valve tissue. Incompetence refers to valves that cause inefficient blood circulation, permitting backflow of blood in the heart.
Medication may be used to treat some heart valve disorders, but many cases require replacement of the native valve with a prosthetic heart valve. In such cases, a thorough assessment of the shape, size, topography, compliance, and other physical properties of the native valve annulus would be extremely beneficial. Prosthetic heart valves can be used to replace any of the native heart valves (aortic, mitral, tricuspid or pulmonary), although repair or replacement of the aortic or mitral valves is most common because they reside in the left side of the heart where pressures are the greatest.
A conventional heart valve replacement surgery involves accessing the heart in the patent's thoracic cavity through a longitudinal incision in the chest. For example, a median sternotomy requires cutting through the sternum and forcing the two opposing halves of the rib cage to be spread apart, allowing access to the thoracic cavity and heart within. The patient is then placed on cardiopulmonary bypass which involves stopping the heart to permit access to the internal chambers. After the heart has been arrested the aorta is cut open to allow access to the diseased valve for replacement. Such open heart surgery is particularly invasive and involves a lengthy and difficult recovery period.
Less invasive approaches to valve replacement have been proposed. The percutaneous implantation of a prosthetic valve is a preferred procedure because the operation is performed under local anesthesia, does not require cardiopulmonary bypass, and is less traumatic.
The present invention provides methods and devices for controlled inflation of a vessel lumen or a hollow portion of an organ located within a patient. The methods and devices may find use in the coronary vasculature, the atrial appendage, the peripheral vasculature, the abdominal vasculature, and in other ducts such as the biliary duct, the fallopian tubes, and similar lumen structures within the body of a patient. The methods and devices may also find use in the heart, lungs, kidneys, or other organs within the body of a patient. Moreover, although particularly adapted for use in vessels and organs found in the human body, the apparatus and methods may also find application in the treatment of animals.
The methods and devices include use of an assessment member that is preferably located at or near the distal end of a catheter or other similar device. The assessment member is introduced to a treatment location within the patient, preferably the native cardiac valve, where the assessment member is activated or otherwise put into use to perform an assessment of one or more physical parameters of the treatment location, to collect the assessment information, and to provide the assessment information to the clinician. Assessment information includes the size (e.g., diameter, circumference, area, volume, etc.) of the valve space, the shape (e.g., round, spherical, irregular, etc.) of the lumen or hollow portion of the organ, the topography (e.g., locations, sizes, and shapes of any irregular features) of the lumen or hollow portion of the organ, the nature of any regular or irregular features (e.g., thrombosis, calcification, healthy tissue, fibrosa) and the spatial orientation (e.g., absolute location relative to a fixed reference point, or directional orientation) of a point or other portion of the treatment location. Access to the treatment location is obtained by any conventional method, such as by general surgical techniques, less invasive surgical techniques, or percutaneously. A preferred method of accessing the treatment location is transluminally, preferably by well-known techniques for accessing the vasculature from a location such as the femoral artery. The catheter is preferably adapted to engage and track over a guidewire that has been previously inserted and routed to the treatment site.
The assessment mechanism includes an expandable member that is attached to the catheter shaft at or near its distal end. The expandable member may comprise an inflatable balloon, a structure containing a plurality of interconnected metallic or polymeric springs or struts, an expandable “wisk”-like structure, or other suitable expandable member. In the case of an inflatable balloon, the expandable member is operatively connected to a source of inflation medium that is accessible at or near the proximal end of the catheter. The expandable member has at least two states, an unexpanded state and an expanded state. The unexpanded state generally corresponds with delivery of the assessment mechanism through the patient's vasculature. The expanded state generally corresponds with the assessment process. The expandable member is adapted to provide assessment information to the user when the expandable member is engaged with a treatment location within the body of a patient.
Turning to several exemplary devices and methods, in one aspect of the invention, a catheter-based system includes a transluminal imaging device contained partially or entirely within an expandable structure attached at or near the distal end of the catheter.
In the preferred embodiments, the expandable member is a balloon member. The balloon member is connected to an inflation lumen that runs between the proximal and distal ends of the catheter, and that is selectively attached to a source of inflation medium at or near the proximal end of the catheter. The balloon member is thereby selectively expandable while the imaging device is located either partially or entirely within the interior of the balloon. The imaging device is adapted to be advanced, retracted, and rotated within the balloon, thereby providing for imaging in a plurality of planes and providing the ability to produce three-dimensional images of the treatment site.
In use, the transluminal imaging device is first introduced to the target location within the patient, such as the native valve annulus. In the preferred embodiment, this is achieved by introducing the catheter through the patient's vasculature to the target location. Typically, the catheter tracks over a guidewire that has been previously installed in any suitable manner. The imaging device may be provided with a radiopaque or other suitable marker at or near its distal end in order to facilitate delivery of the imaging device to the target location by fluoroscopic visualization or other suitable means. Once the imaging device is properly located at the target location, the expandable structure is expanded by introducing an expansion medium through the catheter lumen. The expandable structure expands such that it engages and applies pressure to the internal walls of the target location, such as the valve annulus. The expandable structure also takes on the shape of the internal surface of the target location, including all contours or other topography. Once the expandable structure has been sufficiently expanded, the imaging device is activated. Where appropriate, the imaging device is advanced, retracted, and/or rotated to provide sufficient movement to allow a suitable image of the target location to be created, or to collect a desired amount of measurement information. The measurement information collected and/or the images created by the imaging device are then transmitted to a suitable user interface, where they are displayed to the clinician.
In use, the expandable member is first introduced to the target location within the patient. In the preferred embodiment, this is achieved by introducing the catheter through the patient's vasculature to the target location. The catheter tracks over a guidewire that has been previously installed in any suitable manner. The expandable member carried on the catheter may be provided with a radiopaque or other suitable marker at or near its distal end in order to facilitate delivery of the physical assessment member to the target location by fluoroscopic visualization or other suitable means. Once the expandable member is properly located at the target location, the expandable member is expanded by introducing an expansion medium through the catheter lumen. The expandable member expands to a predetermined size such that the expandable member is able to engage the lumen or hollow portion of the organ, thereby providing an indicator of the shape and orientation of the lumen or hollow portion of the organ. In this way, the clinician is able to obtain precise measurements of the shape and orientation of the lumen or hollow portion of the organ at the target location. In a further preferred embodiment, the expandable member may be expanded to a size greater than the lumen or hollow portion of the organs to provide additional assessment information.
In a further aspect of the present invention, a valvuloplasty procedure is performed in association with the assessment of the native cardiac valve. In an embodiment, the expandable member also functions as a valvuloplasty balloon. The expandable member is placed within the cardiac valve space, where it is expanded. Expansion of the expandable member causes the native valve to increase in size and forces the valve, which is typically in a diseased state in which it is stiff and decreased in diameter, to open more broadly. The valvuloplasty procedure may therefore be performed prior to the deployment of a prosthetic valve, but during a single interventional procedure. In a preferred embodiment, there is controlled inflation and deflation of the expandable member used for valvuloplasty to enhance inflation and deflation rates and pressures for maximum safety and efficacy of the valvuloplasty procedure. A computer processor may be utilized to control the rate of inflation during inflation, the rate of deflation during deflation and during the valvuloplasty procedure. In a further preferred embodiment, the expandable member after performing valvuloplasty may be expanded beyond the shape and size of the native cardiac valve to distort the native cardiac valve and perform an assessment function. The advantages of controlled inflation and deflation of the expanded member may be applied to medical procedures other than valvuloplasty.
The measurement and diagnostic processes performed by any of the foregoing devices and methods may be used to facilitate any suitable medical diagnosis, treatment, or other therapeutic processes. One particular treatment that is facilitated by the foregoing devices and methods is the repair and/or replacement of coronary valves, particularly aortic valve replacement using a prosthetic valve.
Other aspects, features, and functions of the inventions described herein will become apparent by reference to the drawings and the detailed description of the preferred embodiments set forth below.
The present invention is directed to methods and devices for assessing the orientation, shape, size, topography, contours, and other aspects of anatomical vessels and organs using minimally invasive surgical techniques. As summarized above, the devices are typically catheter-based devices. Such devices are suitable for use during less invasive and minimally invasive surgical procedures. However, it should be understood that the devices and methods described herein are also suitable for use during surgical procedures that are more invasive than the preferred minimally invasive techniques described herein.
Before the present invention is described, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these inventions belong. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited.
It must be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.
As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present inventions.
Turning to the drawings,
An inflation port 108 is located near the proximal end of the handle 102. The inflation port 108 is operatively connected to at least one inflation lumen that extends through the catheter shaft 104 to an expandable member 110 located near the distal end of the catheter shaft 104. The inflation port 108 is of any suitable type known to those skilled in the art for engaging an appropriate mechanism for providing an inflation medium to inflate the expandable member 110.
The catheter 100 is adapted to track a guidewire 112 that has been previously implanted into a patient and routed to an appropriate treatment location. A guidewire lumen extends through at least the distal portion of the catheter shaft 104, thereby providing the catheter 100 with the ability to track the guidewire 112 to the treatment location. The catheter 100 may be provided with an over-the-wire construction, in which case the guidewire lumen extends through the entire length of the device. Alternatively, the catheter 100 may be provided with a rapid-exchange feature, in which case the guidewire lumen exits the catheter shaft 104 through an exit port at a point nearer to the distal end of the catheter shaft 104 than the proximal end thereof.
Turning next to
The assessment mechanism includes the outer sheath 120 of the catheter shaft 104, which surrounds the expandable member 110. In the preferred embodiment, the expandable member 110 is an inflatable balloon. The expandable member 110 is attached at its distal end to a guidewire shaft 122, which defines a guidewire lumen 124 therethrough. The guidewire 112 extends through the guidewire lumen 124.
An imaging member 130 is contained within the expandable member 110. The imaging member 130 is supported by a shaft 132 that extends proximally to the handle 102, where it is independently controlled by the user. The imaging member shaft 132 is coaxial with and surrounds the guidewire shaft 124, but is preferably movable (e.g., by sliding) independently of the guidewire shaft 124. At the distal end of the imaging member shaft 132 is the imaging head 134. The imaging head 134 may be any mechanism suitable for transmitting and receiving imaging signals. A typical imaging head 134 is an ultrasonic imaging probe for ultrasound imaging. It is within the scope of the present invention to have other imaging members 130. Such other imaging members 130 may include but not be limited to an optical fiber in conjunction with optical coherence tomography for optical imaging or an acoustic imaging device for transesophageal echo. The expandable member 110 is subject to expansion when a suitable expansion medium is injected into the expandable member through the inflation lumen 126. The inflation lumen 126, in turn, is connected to the inflation port 108 associated with the handle 102.
To use the assessment mechanism illustrated in
In an exemplary embodiment, a valvuloplasty procedure is performed wherein the expandable member is placed within the cardiac valve space, where it is expanded. Expansion of the expandable member causes the native valve to increase in size and forces the valve, which is typically in a diseased state in which it is stiff and, decreased in diameter, to open more broadly.
However, over dilatation of a valvuloplasty expandable member that has a maximum diameter greater than the safe diameter of the aorta can result in injury to the patient. One such type of injury is called an aortic dissection which is when the expandable member over extends the anatomy of the aorta and the aortic wall tears causing the dissection.
While trying to avoid injury, an effective valvuloplasty result is also critical. Acceptable results vary from physician to physician but are usually considered effective if the aortic valve area is approximately doubled after valvuloplasty.
Referring now to
Connected to the catheter 100 is an inflation apparatus 140 which includes a tube 142 for carrying an inflation medium (not shown). Connected to the tube 142 is an inflator apparatus 146 which may be a pump to cause the inflation medium to flow through tube 142 and catheter 100, eventually ending up in expandable member 110 to cause the expandable member 110 to expand to perform a medical procedure, including but not limited to a valvuloplasty procedure. Inflator apparatus 146 may include a metering device to control the flow of inflation medium. Inflator apparatus 146 may also include a volume control to measure the amount of inflation medium passing through the tube 142. After the medical procedure has been completed, the inflator apparatus 146 reverses the flow of the inflation medium to cause the expandable member 110 to deflate. Controlling the inflator apparatus 146 is controller 148. Controller 148 may be connected to inflator apparatus 146 by wire 154 or may communicate wirelessly with inflator apparatus 146. It is within the scope of the present invention for controller 148 to be incorporated into inflator apparatus 146.
Controller 148 may be a computer, computer processor or microprocessor and may include random access memory (RAM), read-only memory (ROM) and a storage device of some type such as a hard disk drive, floppy disk drive, CD-ROM drive, tape drive or other storage device. Controller 148 may also include communication links to provide communication to other devices such as another computer.
Catheter 100 may also include an assessment mechanism as described previously. One such assessment mechanism is an imaging member 130 as described previously which may assist in determining the size, shape and orientation of the expandable member 110 in real time. Other assessment mechanisms may be present such as pressure sensors (for example, a pressure transducer) to measure the pressure in the expandable member 110. For purposes of illustration and not limitation, pressure sensor 152 is shown within expandable member 110. Pressure sensor 152 may also be outside of expandable member 110. Pressure sensor 152 may also be outside of the patient's body, such as on or near catheter handle 102.
The assessment mechanisms provide feedback to controller 148. For this purpose, wire 150 extends from handle 102 of the catheter 100 to the controller 148. Wire 150 may extend up into expandable member 110 to relay information from imaging member 130 and pressure sensor 152 to controller 148. It is within the scope of the present invention for imaging member 130 and pressure sensor 152 to communicate wirelessly with controller 148.
Based on the feedback provided to controller 148 from the assessment mechanisms, controller 148 controls inflator apparatus to vary the rate and the extent of inflation and deflation of the expandable member 110. In one exemplary embodiment, the expandable member may be only partially deflated.
In a preferred embodiment, pressure information and volume information of the expandable member are fed back to controller 148. Pressure information may be obtained from a pressure sensor, for example, while volume information may be obtained from the metering device or volume control which may be located in the inflator apparatus 146. The controller 148 uses an algorithm that tracks inflation pressure, inflation volume and aortic tissue anatomical changes resulting from the change in pressure and volume and in turn controls the inflator apparatus 146 to control the inflation of the expandable member 110.
When the expandable member 110 comes in contact with the aortic wall, the expandable member 110 begins to push the material making up the aortic root/annulus, thus performing valvuloplasty. Increased volume and pressure are required to achieve an effective clinical result. Referring again to
At point D shown in
The various changes in pressure and volume in the interval from point B to point D are fed back to the controller 148 and analyzed there. The interval from point B to point D is characterized as an unsteady rise in pressure and volume. With such characterization, the controller 148 knows that there is valvuloplasty occurring and slows down the rate of inflation of the expandable member 110.
At point E in
The imaging member 130 within expandable member 110 may also assist with assessment information in determining when the expandable member 110 has contacted the aortic wall and the increased expansion of the aortic wall.
The preferred embodiments of the inventions that are the subject of this application are described above in detail for the purpose of setting forth a complete disclosure and for the sake of explanation and clarity. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure. Such alternatives, additions, modifications, and improvements may be made without departing from the scope of the present inventions, which is defined by the claims.
