Pressure-Based Sizing of Body Vessels

Abstract

The present disclosure relates to interventional medical devices, such as sizing catheters, that are useful for various purposes, such as sizing a body vessel for subsequent implantation of an intraluminal medical device. The present disclosure also relates to methods for determining sizing dimensions for a body vessel in a target area, methods for implanting an intraluminal medical device in a target area within a body vessel, and methods for fabricating an intraluminal medical device.

Description

[Technical Field]

[0001] The present disclosure relates generally to the field of medical devices. More particularly, the present disclosure relates to interventional medical devices, such as catheters, kits, and methods, useful for various purposes, such as sizing a body vessel for subsequent implantation of an intraluminal medical device. The present disclosure also relates to methods of implanting an intraluminal medical device in a target area within a body vessel, and methods of making an intraluminal medical device. [Background technology]

[0002] Measurement of vessel dimensions using imaging techniques and devices, such as venography and intravascular ultrasound, is often used to size body vessels prior to implantation of intraluminal medical devices within the body vessels. Vascular sizing can be an important factor in achieving desired therapeutic outcomes after implantation of intraluminal medical devices, such as stents, valves, filters, and other devices.

[0003] Sizing compliant body vessels, such as veins, lymphatic vessels, and other body vessels, is particularly important to achieving desired results because these body vessels naturally dilate to a range of diameters in response to changes in pressure on the interior surface of their walls. For example, veins dilate to a range of diameters due to changes in internal pressure as fluid flows through the body vessel. The ability of these body vessels to naturally dilate increases the importance of sizing the vessels prior to implantation of an intraluminal medical device. If the body vessel dilates beyond the diameter of a device implanted within the body vessel, the device may migrate from its original, intended implanted location.

[0004] Unfortunately, the very characteristics that make pre-implant vessel sizing—extent—important also make sizing these body vessels particularly challenging. Conventional sizing devices and techniques either fail to incorporate vessel extent or otherwise rely on devices and techniques that fail to account for vessel extent.

[0005] Therefore, a need remains for new and improved interventional medical devices, kits, and methods useful for various purposes, such as sizing body vessels for subsequent implantation of intraluminal medical devices. A need also exists for related methods, such as methods for implanting intraluminal medical devices in target areas within body vessels and methods for fabricating intraluminal medical devices. Summary of the Invention [Means for solving the problem]

[0006] Various example interventional medical devices useful for sizing body vessels are described.

[0007] One example interventional medical device includes a sizing catheter having an elongate main body having a proximal end and a distal end, and a balloon disposed on the main body adjacent the distal end and defining a cavity. The main body defines an inflation lumen having a proximal opening on or near the proximal end of the main body and a distal opening disposed within the cavity of the balloon. The balloon is movable between an inflated configuration and a deflated configuration by passing fluid through the inflation lumen into the cavity and withdrawing fluid from the cavity through the inflation lumen. The balloon has an axial length along which pressure transmitted to tissue in contact with the balloon is known to be a particular inflation pressure. In some instances, the balloon is more compliant along the axial length and less compliant along axial portions beyond the axial length.

[0008] Various example kits useful for sizing body vessels are described.

[0009] An example kit includes a sizing catheter according to one embodiment and a pressure transducer adapted to be operably connected to the sizing catheter and used to maintain pressure on the inner surface of a body vessel at a target region within the body vessel, e.g., a sizing pressure for a specific target region within a specific body vessel.

[0010] Various example methods are described for determining sizing dimensions of a body vessel at a region of interest within the body vessel.

[0011] An example method for determining sizing dimensions of a body vessel at a target region within the body vessel includes applying a sizing pressure to an inner surface of the body vessel at the target region within the body vessel; maintaining the sizing pressure against the inner surface of the body vessel at the target region; generating a visual representation of the target region; and measuring the dimensions of the body vessel at the target region on the visual representation to provide a sizing dimension of the body vessel at the target region within the body vessel.

[0012] Another example method for determining sizing dimensions of a body vessel at a target region in the body vessel includes positioning a pressurizing device within the body vessel at the target region; using the pressurizing device to apply a sizing pressure to an inner surface of the body vessel at the target region in the body vessel; maintaining the sizing pressure against the inner surface of the body vessel at the target region; generating a visual representation of the target region showing a portion of the pressurizing device within the target region of the body vessel; and measuring dimensions on the visual representation to provide a sizing dimension of the body vessel at the target region in the body vessel.

[0013] Another example method for determining sizing dimensions of a body vessel at a target region in the body vessel includes navigating a sizing catheter having a compliant balloon through the body vessel to a target region within the body vessel; inflating the compliant balloon to an inflation pressure to apply a corresponding sizing pressure against the inner surface of the body vessel at the target region; maintaining the inflation pressure on the compliant balloon; generating a visual representation of the target region showing the inflated compliant balloon within the body vessel at the target region; and measuring the dimensions of the inflated compliant balloon on the visual representation to provide a sizing dimension of the body vessel at the target region within the body vessel.

[0014] Various methods have been described for implanting intraluminal medical devices in regions of interest within body vessels.

[0015] An example method for implanting an intraluminal medical device at a target region within a body vessel includes applying a sizing pressure to an inner surface of the body vessel at the target region within the body vessel; maintaining the sizing pressure on the inner surface of the body vessel at the target region within the body vessel; generating a visual representation of the target region; measuring a dimension of the body vessel at the target region on the visual representation to provide a sizing dimension for the body vessel at the target region within the body vessel; and implanting an intraluminal medical device adapted to maintain the sizing dimension within the body vessel. An optional step performed after the measuring step, and if included, before the implanting step, includes verifying that the sizing dimension of the body vessel is within a range of therapeutic dimensions for the intraluminal medical device.

[0016] Another example method of implanting an intraluminal medical device in a target region within a body vessel includes positioning a pressurizing device within the body vessel at the target region; using the pressurizing device to apply a sizing pressure to an inner surface of the body vessel at the target region within the body vessel; maintaining the sizing pressure against the inner surface of the body vessel at the target region; generating a visual representation of the target region showing a portion of the pressurizing device within the target region of the body vessel; measuring dimensions on the visual representation to provide a sizing dimension of the body vessel at the target region within the body vessel; and implanting an intraluminal medical device adapted to maintain the sizing dimension within the body vessel. An optional step performed after the measuring step, and if included, before the implanting step, includes verifying that the sizing dimension of the body vessel is within a range of therapeutic dimensions for the intraluminal medical device.

[0017] Another example method for implanting an intraluminal medical device at a target region within a body vessel includes navigating a sizing catheter having a compliant balloon through the body vessel to a target region within the body vessel; inflating the compliant balloon to an inflation pressure to apply a corresponding sizing pressure against the interior surface of the body vessel at the target region; maintaining the inflation pressure on the compliant balloon; generating a visual representation of the target region showing the inflated compliant balloon within the body vessel at the target region; measuring dimensions of the inflated compliant balloon on the visual representation to provide a sizing dimension of the body vessel at the target region within the body vessel; and implanting an intraluminal medical device adapted to maintain the sizing dimension within the body vessel. An optional step performed after the measuring step, and if included, before the implanting step, includes verifying that the sizing dimension of the body vessel is within a range of therapeutic dimensions for the intraluminal medical device.

[0018] Another example method for implanting an intraluminal medical device at a target region within a body vessel includes applying a first pressure to an inner surface of the body vessel at the target region within the body vessel; maintaining the first pressure on the inner surface of the body vessel at the target region; generating a visual representation of the target region; measuring dimensions of the body vessel at the target region on the visual representation to provide representative dimensions of the body vessel at the target region within the body vessel; repeating the applying, maintaining, generating, and measuring steps using a second pressure different from the first pressure; generating a curve using the first and second pressures and the corresponding first and second measured dimensions; identifying a sizing pressure for the curve; identifying a sizing dimension corresponding to the sizing pressure for the curve; and implanting the intraluminal medical device adapted to maintain the sizing dimension within the body vessel at the target region within the body vessel.

[0019] Various methods for making intraluminal medical devices have been described.

[0020] An example method of fabricating an intraluminal medical device includes applying a sizing pressure to an inner surface of a body vessel at a target region within the body vessel; maintaining the sizing pressure on the inner surface of the body vessel at the target region; generating a visual representation of the target region; measuring dimensions of the body vessel at the target region on the visual representation to provide sizing dimensions of the body vessel at the target region within the body vessel; and fabricating an intraluminal medical device adapted to apply a target pressure, e.g., a sizing pressure, to the inner surface of a body vessel at the target region within the body vessel.

[0021] Various methods for making multiple intraluminal medical devices have been described.

[0022] An example method for fabricating a plurality of intraluminal medical devices includes applying a first pressure to an interior surface of a body vessel at a region of interest within the body vessel; maintaining the first pressure against the interior surface of the body vessel at the region of interest; generating a visual representation of the region of interest; measuring dimensions of the body vessel at the region of interest on the visual representation to provide representative dimensions for the body vessel at the region of interest within the body vessel; repeating the applying, maintaining, generating, and measuring steps using a second pressure different from the first pressure; and measuring the first and second pressures and the corresponding first and second measured dimensions. identifying a first sizing dimension corresponding to the first sizing pressure for the curve; identifying a second sizing dimension corresponding to the second sizing pressure for the curve; fabricating a first intraluminal medical device adapted to apply a first target pressure, e.g., the first sizing pressure, to an inner surface of a body vessel; and fabricating a second intraluminal medical device adapted to apply a second target pressure, e.g., the second sizing pressure, to an inner surface of a body vessel.

[0023] Additional understanding of these and other example interventional medical devices, kits, and methods can be obtained by reviewing the detailed description and referenced drawings of selected examples below. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a perspective view of an example interventional medical device. [Figure 2] 2 is a cross-sectional view of a body vessel within which the example interventional medical device shown in FIG. 1 is placed. [Figure 2A] FIG. 10 is a side view of a distal portion of an alternative interventional medical device. [Figure 2B] FIG. 10 is a side view of a distal portion of an alternative interventional medical device. [Figure 2C] FIG. 10 is a side view of a distal portion of an alternative interventional medical device. [Figure 3] FIG. 1 is a schematic diagram of an example kit. [Figure 4] FIG. 1 is a flowchart diagram of an example method for determining a representative dimension of a body vessel in a region of interest within the body vessel. [Figure 5] FIG. 10 is a flowchart diagram of another example method for determining a representative dimension of a body vessel in a region of interest within the body vessel. [Figure 6] FIG. 10 is a flowchart diagram of another example method for determining a representative dimension of a body vessel in a region of interest within the body vessel. [Figure 7] FIG. 1 is a flowchart diagram of an example method for implanting an intraluminal medical device in a target region within a body vessel. [Figure 8] FIG. 10 is a flowchart diagram of another example method for implanting an intraluminal medical device in a target region within a body vessel. [Figure 9] FIG. 10 is a flowchart diagram of another example method for implanting an intraluminal medical device in a target region within a body vessel. [Figure 10] FIG. 10 is a flowchart diagram of another example method for implanting an intraluminal medical device in a target region within a body vessel. [Figure 11] FIG. 1 is a flow chart diagram of an example method for making an intraluminal medical device. [Figure 12] FIG. 1 is a flowchart diagram of an example method for fabricating multiple intraluminal medical devices. [Figure 13] 1 shows a schematic diagram of the pressure-diameter curve and the pressure plateau region of the curve for a typical model body vessel. [Figure 14] 1 shows a simulated pressure-diameter curve for a human vein, illustrating the expected pressure plateau region over a pressure range from about 30 mmHg to about 120 mmHg. [Figure 15] 1 shows pressure-diameter curves for the right external iliac vein of a porcine model based on experimental data. [Figure 16] Shown are simulated pressure-diameter curves, pressure-diameter curves based on experimental data acquired using the methods described herein, and pressure-diameter curves based on research data acquired using IVUS. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following detailed description and accompanying drawings describe and illustrate various examples of interventional medical devices, kits, and methods useful for sizing body vessels, methods of implanting intraluminal medical devices, and methods of fabricating intraluminal medical devices. The inclusion of these selected example descriptions is not intended to limit the scope of the invention or its protection in any way. The invention can be practiced or performed in various ways, and the examples described and illustrated herein are not to be considered exhaustive or limiting. Rather, the description and illustration of these examples are provided to enable one skilled in the art to make and use interventional medical devices, such as sizing catheters and kits, and to perform methods useful for sizing body vessels, and methods of implanting intraluminal medical devices in target areas within body vessels, and methods of fabricating intraluminal medical devices.

[0026] The term "body vessel" as used herein refers to a tubular biological structure located within the body of an animal, such as a human, and having a wall defining a lumen. Examples of body vessels include, but are not limited to, blood vessels, such as arteries and veins, lymphatic vessels, digestive vessels, such as the esophagus, large intestine, and small intestine, and airway vessels, such as the trachea.

[0027] As used herein, the term "representative dimensions of sizing dimensions" refers to the dimensions of an interventional medical device, e.g., a sizing catheter, or a component of an interventional medical device, e.g., a balloon, measured while the interventional medical device or component of the interventional medical device applies pressure, e.g., a sizing pressure, to the interior surface of a body vessel in a target area.

[0028] The term "sizing dimension" as used herein refers to the dimension of a body vessel determined by the sizing pressure for the body vessel. The sizing dimension may be the orthogonal inner diameter of the body vessel extending in a plane perpendicular to the longitudinal axis of the body vessel.

[0029] The term "sizing pressure" as used herein refers to a known, constant pressure applied to the interior surface of a body vessel in sizing the body vessel. The sizing pressure may be a pressure within a range of pressures, over which increasing pressure results in minimal increase in the diameter of the body vessel and no permanent structural change to the body vessel. The sizing pressure may also be a pressure below the pressure that results in permanent changes to the structure of the body vessel in response to pressure applied to the interior surface of the body vessel. The sizing pressure may also be a pressure that lies within the pressure plateau region of a pressure-diameter curve that shows the vessel diameter over a range of known, constant pressures for a particular type of body vessel, a particular location within a particular type of body vessel or a particular body vessel, a particular body vessel in a particular animal, or any other identifiable body vessel type. Figure 13 shows a schematic diagram of the pressure-diameter curve and the pressure plateau region of the curve for a generic model body vessel. Figure 14 shows a simulated pressure-diameter curve for a human vein, illustrating the expected pressure plateau region over a pressure range of approximately 30 mmHg to approximately 120 mmHg. The rate of change in diameter between successive pressure increments in the plot is approximately 1 mm or less over this pressure plateau region. Different vessels are expected to have different pressure plateau values ​​based on their mechanical properties, but are expected to exhibit vessel-specific pressure plateau regions over a range of pressures. Figure 15, for example, shows the pressure-diameter curve for the right external iliac vein in a porcine model based on fluoroscopy. The mean venous diameter was measured at sizing catheter pressures ranging from 30 to 120 mmHg. The vein was imaged in four planes per pressure. The venous diameter was measured in each plane, and the four values ​​observed per pressure were averaged to obtain the reported value. Furthermore, measurements were taken at two locations along the length of the sizing catheter. For this body vessel in this model, the expected pressure plateau region occurs over a pressure range of approximately 60 mmHg to approximately 120 mmHg. Sizing pressure may also be the pressure that produces the sizing dimensions used to select a particular medical device, above which the medical device will not move under normal physiological conditions, but below which permanent changes will occur in the structure of the body's vasculature.A sizing pressure may also be the pressure that results in the sizing dimensions used to select a particular medical device, at which the medical device is expected to have optimal performance for the particular medical device in a particular type of body vessel, a particular body vessel, a particular body vessel in a particular animal, or any other identifiable body vessel type, location within a body vessel, or within a particular body vessel.

[0030] The terms "therapeutic size" and "range of therapeutic sizes" as used herein refer to a size or range of sizes, as appropriate, for which a medical device is designed and intended to function.

[0031] Pressure within a body vessel controls the expansion of the body vessel. As pressure within the body vessel increases, the relative amount of expansion of the body vessel decreases. There is a pressure at which the body vessel achieves sufficient expansion; there is a pressure at which sufficient expansion is actually achieved, but at a risk of damaging the body vessel. As defined above, there is a sizing pressure at which further expansion of the vessel at increased pressure is not critical to device sizing and the vessel is not damaged.

[0032] The inventors have determined that sizing a body vessel at a sizing pressure provides sizing-related information, e.g., sizing dimensions, suitable for use in various methods, e.g., methods for implanting intraluminal medical devices, while avoiding pressures that may damage the body vessel during the sizing process. In order to measure a dimension of a body vessel, such as an internal diameter, it is necessary to know the relationship between the extent of the body vessel and the pressure applied within the body vessel without damaging the body vessel. Applying a sizing pressure to the body vessel wall allows imaging at the appropriate vessel extent and obtains sizing dimensions for sizing a device without damaging the body vessel.

[0033] Although there are many devices developed to dilate a body vessel in order to change its structure or occlude it, and many of these devices measure intra-device pressure, there is a need for a device that is intended to open a body vessel with a sizing pressure to determine a sizing dimension of the body vessel for implantation of the device. Existing devices and methods for sizing a vessel are not intended to apply a sizing pressure to obtain a sizing dimension to properly size the device.

[0034] Figure 1 illustrates an example interventional medical device 100 useful for sizing a body vessel. Figure 2 illustrates the interventional medical device 100 positioned within a lumen 214 of a body vessel 200 during an example method, such as method 2000 described below and shown in Figure 5.

[0035] Interventional medical device 100 is a sizing catheter. Interventional medical device 100 includes an elongate main body 110 having a proximal end 112 and a distal end 114. A balloon 116 is disposed on main body 110 adjacent distal end 114, defining a cavity 118. Main body 110 defines an inflation lumen 120 having a proximal opening 122 on or near proximal end 112 of main body 110 and a distal opening 124 disposed within cavity 118 of balloon 116. Balloon 116 is movable between an inflated configuration and a deflated configuration by passing fluid through inflation lumen 120 into and withdrawing fluid from cavity 118 through inflation lumen 120.

[0036] The balloon 116 has an axial length 130 along which the pressure transmitted to the tissue in contact with the balloon 116 is known to be at least a single nominal pressure, and advantageously, a range of nominal pressures. As best shown in FIG. 1 , this axial length 130 may be a portion of the total axial length of the balloon 116. In some embodiments, such as the embodiment shown in FIG. 1 , the thickness of the wall of the balloon 116 along this axial length 130 is less than the thickness at axially disposed ends 132, 134 beyond the axial length 116. This structural configuration is advantageous because it provides a more compliant balloon 116 at least along the axial length 130, allowing the balloon to better conform to the vessel wall along this axial length 116, and is less compliant along the ends of the balloon 116 beyond the axial length 130.

[0037] In some embodiments, the balloon 116 is configured to have an elastic compliance that exceeds the elastic compliance of the body vessel in which the catheter 100 is intended to be used. For example, the elastic compliance of the balloon may be several times the elastic compliance of the body vessel in which the catheter 100 is intended to be used, such as twice (2X) the elastic compliance of the body vessel in which the catheter 100 is intended to be used, three times (3X) the elastic compliance of the body vessel in which the catheter 100 is intended to be used, five times (5X) the elastic compliance of the body vessel in which the catheter 100 is intended to be used, and ten times (10X) the elastic compliance of the body vessel in which the catheter 100 is intended to be used.

[0038] In some embodiments, the maximum inflated diameter of balloon 116 exceeds the expected inner diameter of the body vessel in which catheter 100 is intended to be used. For example, the maximum inflated diameter of the balloon may be several times the expected inner diameter of the body vessel in which catheter 100 is intended to be used, such as twice (2x) the expected inner diameter of the body vessel in which catheter 100 is intended to be used, three times (3x) the expected inner diameter of the body vessel in which catheter 100 is intended to be used, four times (4x) the expected inner diameter of the body vessel in which catheter 100 is intended to be used, and five times (5x) the expected inner diameter of the body vessel in which catheter 100 is intended to be used. In one particular example, a catheter intended to be used in a body vessel expected to have an inner diameter of 12 mm includes a balloon with a maximum inflated diameter of 48 mm.

[0039] In some embodiments, the catheter includes a pressure relief valve that can be opened to prevent application of pressure above the sizing pressure to the body vessel, in these instances, the pressure relief valve can be on the handle end of the catheter or can be located on the balloon.

[0040] 2 illustrates an interventional medical device 100 shown positioned within a body vessel 200, such as during the performance of one method in accordance with the present invention. The body vessel 200 includes a vascular wall 210 defining a lumen 214. The interventional medical device 100 is positioned within the lumen 214. The balloon 116 is in an expanded configuration inflated to an inflation pressure represented by arrow 230, thereby producing a sizing pressure represented by arrow 240 that is transmitted along the axial length 130 of the balloon 116 to an inner surface 212 of the vascular wall 210 of the body vessel 200. The interventional medical device 100 is in operation to maintain the sizing pressure 240 against the inner surface 216 of the vascular wall 210 for a period of time, resulting in a sizing dimension 250 of the body vessel 200 that can be measured on a visual representation of the illustrated region of the body vessel 200. Dimensions other than sizing dimension 250, such as dimensions 252, 254, represent the diameter of body vessel 200 without sizing pressure 240 being applied to inner surface 212 of vessel wall 210.

[0041] Interventional medical devices according to embodiments may include additional and alternative structural components and arrangements, including components that facilitate use of the interventional medical device in methods according to embodiments. For example, as shown in FIG. 2A , interventional medical device 100 may include a cannula 170, e.g., a metallic cannula, disposed across a portion of elongate main body 110 within cavity 118 of balloon 116. If included, cannula 170 may be free-floating across that portion of elongate main body 110 within cavity 118 of balloon 116, or may be attached to elongate main body 110 such that cannula 170 is fixed in place within cavity 118 within balloon 116. If attached, any suitable attachment may be used, such as staking, adhesive, etc. The distal opening 124 of the inflation lumen 120 may be positioned relatively more proximally or distally within the cavity 118 of the balloon 116 relative to the position shown in FIG. 1 to avoid obstruction of fluid flow through the distal opening 124 due to the presence of the cannula 170. The inclusion of the cannula 170 is considered advantageous because at least the cannula 170 can be precisely manufactured to a specific, known length that can be used as a calibration standard during use of the interventional medical device 100. While markers placed at known distances from each other on the elongated main body 110 could be used as calibration standards, the elongated main body 110 may bend or otherwise distort during inflation of the balloon 116, obscuring the distance between the markers and, in turn, making the markers unreliable as a calibration standard. The presence of the cannula 170 prevents, or substantially prevents, such bending, providing a reliable calibration standard across the full range of potential pressures used to inflate the balloon 116. For at least this reason, it is considered particularly advantageous to include a cannula 116 in the interventional medical equipment used in the methods described herein.

[0042] Interventional medical devices according to embodiments may include additional and alternative structural components and arrangements that facilitate their use in methods according to embodiments with particular imaging modalities. For example, FIGS. 2B and 2C each illustrate an interventional medical device configured for use with intravascular ultrasound (IVUS) imaging. In FIG. 2B, interventional medical device 180 includes an elongate main body 181 defining a lumen 182 that may accommodate a wire guide and an IVUS catheter 183 having an ultrasound transducer 184. The one or more transducers may be a phased array, a rotating single element, a linear array, or any other form known to those skilled in the art of IVUS catheter design. Because IVUS catheter 183 is movable within lumen 182, transducer 184 may be positioned within a portion 185 of elongate main body 181 that is disposed within balloon 186. The material of the elongate main body 110 at this section 185 is made of an echolucent material to allow ultrasound signals transmitted and received by the transducer 184 to pass through the section 185. The balloon 186 can also be made of an echolucent material to facilitate transmission of such signals through the balloon and allow visualization of the exterior of the balloon 186. Examples of suitable echolucent materials include, but are not limited to, methyl methacrylate butadiene styrene copolymer (MBS), acrylonitrile butadiene styrene (ABS), methacrylate-acrylonitrile-butadiene-styrene (MABS), and styrene butadiene block copolymer (SBC), polymethylpentene (PMP), polyethylene (PE), polyamide (e.g., nylon), and polyimide. Alternatively, the balloon 186 can include echogenic features that allow clear visualization of multiple locations on the balloon. A couplant 187 is disposed within the balloon 186 when inflated to allow transmission of the ultrasound signal 188 between different interfaces with minimal signal loss. The couplant 187 should have a similar acoustic impedance to the balloon 186 and the vessel wall adjacent to the balloon 186 to allow maximum transmission of the ultrasound signal 188.Suitable couplants include, but are not limited to, biocompatible fluids such as saline, oils such as mineral oil or soybean oil, alcohol, or other fluids.

[0043] 2C, interventional medical device 190 includes an elongate main body 191 with an ultrasound transducer 192 integrated into elongate main body 191 such that transducer 192 is positioned within balloon 193. When balloon 193 is inflated by couplant 194, ultrasound signals 195 only need to be transmitted and / or received through the materials of couplant 194 and balloon 193, thereby minimizing any potential attenuation of the signal. In additional embodiments, multiple transducers may be positioned along the length of the balloon, allowing for multiple locations to be evaluated simultaneously.

[0044] FIG. 3 illustrates a kit 300 useful for sizing a body vessel. The kit 300 includes the sizing catheter 100 described above and shown in FIGS. 1 and 2 and a pressure maintenance device 310 operably connected to the sizing catheter and adapted to maintain a target pressure, e.g., a pressure suitable for applying a sizing pressure to the interior surface of the body vessel within the balloon of the sizing catheter. Instructions for use 312 may also be included in the kit 300. In the illustrated embodiment, the pressure maintenance device 310 includes a pressure transducer. Another device suitable for maintaining a target pressure within the balloon of the sizing catheter may be included in a kit according to an embodiment as the pressure maintenance device 310, e.g., a pressure gauge, pressure indicator that correlates pressure to diameter, pressure to volume, or both, or other suitable device adapted to maintain a target pressure within the balloon of the sizing catheter. Alternatively, a known constant pressure source adapted to be operably connected to the sizing catheter to maintain a target pressure within the balloon of the sizing catheter may be included in a kit according to an embodiment. For example, a known constant pressure inflation source such as a regulated pressure supply or a defined column of liquid such as water. In one embodiment, the kit includes a syringe adapted to be operably connected to the sizing catheter and including an indicator of the volume of fluid to inject to achieve a given pressure specified by the manufacturer.

[0045] Methods for determining a sizing dimension of a body vessel in a region of interest are provided. Figures 4, 5, and 6 each illustrate an example method according to this aspect of the invention. These and other implementations of the methods according to this aspect of the invention provide a sizing dimension of a body vessel by measuring a dimension on a visual representation of the body vessel while a sizing pressure is maintained against the interior surface of the body vessel. In some example methods, such as method 1000 shown in Figure 4 and described below, the sizing dimension is a dimension of the body vessel, e.g., the inner diameter of the body vessel perpendicular to the longitudinal axis of the body vessel. In other example methods, such as method 1200 shown in Figure 6 and described below, the sizing dimension is a dimension of a pressurizing device, e.g., a sizing catheter, placed within the body vessel as part of the implementation of the method.

[0046] An example method for determining a sizing dimension of a body vessel in a region of interest includes measuring a dimension on a visual representation of the body vessel while a sizing pressure is maintained against the interior surface of the body vessel. In some examples, the sizing dimension is a dimension of the body vessel, such as an orthogonal inner diameter of the body vessel. In other examples, the sizing dimension is a dimension of a pressurizing device used in the method to apply the sizing pressure to the interior surface of the body vessel.

[0047] 4 illustrates an example method 1000 for determining sizing dimensions of a body vessel at a region of interest within a body vessel. An initial step 1010 includes applying a sizing pressure to an inner surface of the body vessel at the region of interest within the body vessel. Another step 1012 includes maintaining the sizing pressure on the inner surface of the body vessel at the region of interest. Another step 1014 includes generating a visual representation of the region of interest. Another step 1016 includes measuring dimensions of the body vessel at the region of interest on the visual representation to provide sizing dimensions of the body vessel at the region of interest within the body vessel.

[0048] Method 1000, and indeed all methods in accordance with the present invention, may be practiced in any suitable body vessel within the body of an animal, including humans and non-human animals. Examples of suitable body vessels include, but are not limited to, arteries, veins, lymphatic vessels, digestive tract vessels such as the esophagus, small intestine, and large intestine, respiratory tract vessels, and other body vessels. Methods in accordance with the present invention are particularly advantageous for practice in compliant body vessels, such as veins and lymphatic vessels, at least because these vessels are difficult to assess dimensionally using conventional techniques.

[0049] Similarly, method 1000, and indeed all methods in accordance with the present invention, may be performed in any suitable region of interest within a body vessel. Examples of suitable regions of interest include locations within a body vessel adjacent to external anatomical features or structures within the body, such as the location of a natural valve within a body vessel, e.g., the location of a natural venous valve within a vein, the location of an opening to a branch vessel, or an adjacent body vessel. For example, a method in accordance with the present invention may be performed in the region of a human's left common iliac vein that is compressed by the overlying right common iliac artery, such as compression that may occur in May-Thurner syndrome.

[0050] Step 1010 of applying a sizing pressure to the interior surface of the body vessel at the region of interest within the body vessel can be performed using a variety of pressurization devices and techniques. Examples of suitable pressurization devices for applying a sizing pressure include, but are not limited to, balloon-containing sizing catheters, such as those shown in FIGS. 1 and 2 and described above, expandable intraluminal baskets, and other intraluminal pressurization medical devices, including compliant balloon-containing sizing catheters. Compliant balloon-containing sizing catheters are considered particularly advantageous, at least because their expandability allows the balloon to sufficiently conform to the interior surface of the body vessel adjacent the balloon or portion of the balloon to distribute pressure evenly therealong. A balloon-containing sizing catheter used in method 1000 advantageously includes components for controlling inflation and deflation, and therefore the pressure of the balloon, such as a valve controlling the passage of inflation fluid into and out of the inflation lumen and balloon, a pressure transducer including the valve and a controller for setting a particular desired pressure, or other suitable components. Examples of suitable techniques for applying sizing pressure to the interior surface of a body vessel include, but are not limited to, inflating the balloon of a sizing catheter by passing an inflation fluid, such as saline or other liquid or carbon dioxide or other suitable gas, through the inflation lumen of the catheter and into the balloon, causing inflation of the balloon. Advantageously, sizing catheters used in method 1000 that include a balloon are characterized so that the relationship between inflation pressure and sizing pressure delivered to the tissue is known along a specified length of the balloon. The rate of change of this relationship over time, if any, is also advantageously characterized for any sizing catheter used in method 1000.

[0051] In performing step 1010 of applying a sizing pressure, the sizing pressure can be any suitable sizing pressure, and one skilled in the art can select an appropriate or desirable sizing pressure for a particular example method based on various considerations, including the type of body vessel in which the method is being performed, the nature of the target location within the body vessel in which the method is being performed, and any anticipated uses of the sizing dimension to be determined by performing the method. Examples of suitable pressures that can be used as a sizing pressure in the example method include, but are not limited to, the maximum pressure to which the inner surface of the body vessel in the target area is expected to be naturally exposed, pressures applied by intraluminal medical devices adapted for implantation at the target point within the body vessel, such as self-expanding frames within stents, stents that require force input to achieve radial expansion, such as frames within balloon-expandable stents, valve devices, or support frames within other intraluminal medical devices, and other pressures. Advantageously, the sizing pressure is below a pressure that would cause dilation of the body vessel accompanied by permanent structural changes to the body vessel. In veins, specific examples of suitable pressures that may be used as sizing pressures in the methods according to the examples include pressures greater than 0 mmHg and less than about 1000 mmHg, pressures greater than 0 mmHg and less than about 750 mmHg, pressures greater than 0 mmHg and less than about 500 mmHg, pressures greater than 0 mmHg and less than about 250 mmHg, pressures greater than 0 mmHg and less than about 200 mmHg, pressures greater than 0 mmHg and less than about 150 mmHg, pressures greater than 0 mmHg and less than about 130 mmHg, pressures greater than 0 mmHg and less than about 120 mmHg, These include, but are not limited to, pressures less than about 10 mmHg, pressures less than about 20 mmHg, pressures less than about 30 mmHg, pressures less than about 40 mmHg, pressures less than about 50 mmHg, pressures less than about 60 mmHg, pressures less than about 70 mmHg, pressures less than about 80 mmHg, pressures less than about 90 mmHg, pressures less than about 100 mmHg, pressures less than about 110 mmHg, pressures less than about 120 mmHg, pressures less than about 130 mmHg, pressures less than about 140 mmHg, and pressures less than about 150 mmHg.

[0052] Step 1012 of maintaining a sizing pressure against the inner surface of the body vessel in the target region can be performed using techniques suitable for any device used in step 1010 of applying a sizing pressure. For example, if the device includes a valve controlling the passage of inflation fluid into a balloon, such as in a sizing catheter, the valve can be closed once the sizing pressure is achieved in the balloon, preventing further inflation fluid from passing into the balloon and preventing inflation fluid in the balloon or inflation lumen of the sizing catheter from being removed from the balloon or inflation lumen. For balloons that exhibit some degree of creep, fluid can be added as needed to maintain the sizing pressure in response to the creep. It is noted that in this and all methods, step 1012 of maintaining a sizing pressure can be performed by maintaining the relevant sizing pressure, or a range of pressures that includes the relevant sizing pressure, for a period of time. Maintaining a sizing pressure can also include maintaining a set rate of change for pressure in the system so that a point in time when sizing pressure was present can be determined. Also, balloons constructed of viscoelastic materials or other materials that have a time-dependent mechanical response under relevant conditions may exhibit a small amount of creep, which can result in a pressure drop over time. Thus, maintaining the sizing pressure may be accomplished by adding fluid to account for this creep.

[0053] Step 1014 of generating a visual representation of a region of interest can be performed using any medical imaging modality suitable for generating a visual representation of a region of interest in a body vessel. One skilled in the art would be able to select a suitable medical imaging modality for use in a particular example method based on various considerations, including the body vessel and the region of interest within the body vessel, patient-specific considerations, concerns about X-ray and MRI exposure, and other considerations. Examples of suitable medical imaging modalities include, but are not limited to, radiography, X-ray computed tomography, X-ray fluoroscopy, venography, ultrasound, and magnetic resonance imaging (MRI). For veins, venography, which involves the injection of a contrast agent into a balloon, is considered particularly advantageous because at least the balloon is perfectly aligned with the interior surface of the body vessel, thereby showing the interior surface of the body vessel in the resulting image.

[0054] In step 1014, the visual display may include any suitable visual image, including a film-recorded image, e.g., an X-ray image; a digital still image, e.g., stored on a computer hard drive, random access memory, flash memory, e.g., a solid-state drive or USB flash drive, or other suitable digital storage medium; a series of multiple such digital still images, e.g., a series of still images taken over a period of time; a series of multiple such digital still images taken from multiple angles, e.g., a range of angles; and a digital video stored on a suitable digital storage medium, such as those listed above. The type and number of visual images generated during step 1014 may depend on the medical imaging modality used. For example, in medical imaging modalities that are not three-dimensional, it may be advantageous to take multiple images of the region of interest from multiple angles. These multiple images may then be used in step 1016, for example, to measure the dimensions of the body vessel, as described below.

[0055] Advantageously, step 1014 of generating a visual representation of the region of interest is performed while step 1012 of maintaining a sizing pressure against the surface of the body vessel in the region of interest is being performed. This time relationship between the performance of steps 1012, 1014 ensures that step 1016 of measuring a dimension on the visual representation provides a sizing dimension of the body vessel in the region of interest while a sizing pressure is maintained against the interior surface of the body vessel in the region of interest.

[0056] Step 1016 of measuring a dimension of a body vessel in the region of interest on the visual representation may be performed using any suitable technique and any suitable tools, including manual tools and software. For example, if the medical imaging modality used in step 1014 includes digital imaging capabilities and image analysis software, measurement tools within the image analysis software may be used to set opposing points on the interior surface of the body vessel, generate lines between the opposing points, and calculate the distance between the points on a scale related to the body vessel and not necessarily the image. Any suitable dimension of the body vessel may be measured in step 1016. Conveniently, the dimension is the width of the body vessel extending from a first point on the interior surface of the body vessel to a second point on the interior surface of the body vessel opposite the first point relative to the axis of the body vessel in the region of interest. In some examples, the sizing pressure is a pressure that circularizes a body vessel in the target region, and the sizing dimension is an inner diameter of the body vessel extending between a first point and a second point on the inner surface of the body vessel in the target region and on a plane perpendicular to the axis of the body vessel. In other examples, the sizing pressure is a pressure that is less than the pressure that sufficiently circularizes a body vessel in the target region. For example, in methods in which a sizing catheter is used in step 1010 to apply a sizing pressure to the inner surface of a body vessel in the target region within the body vessel, a balloon that is too large (i.e., a balloon with too much material) relative to the expected natural maximum size of the body vessel may not be sufficiently inflated using a pressure that allows the balloon to conform to the inner surface of the body vessel without expanding the body vessel or even changing the surface area of ​​the inner surface of the body vessel in any substantial way. These examples can be beneficial when the region of interest includes one or more tributary vessels of a body vessel because an under-inflated balloon may extend slightly into the lumen of one or more tributary vessels to conform to the inner surface of the body vessel, allowing the presence, size, or both of the one or more tributary vessels to be incorporated into step 1016 of measuring the size of the body vessel in the region of interest on the visual display.

[0057] Multiple dimensions may be measured, if appropriate, during performance of step 1016. For example, as described above, when a non-three-dimensional medical imaging modality is used in performance of step 1014, it may be advantageous to take multiple images of the region of interest from multiple angles. Using fluoroscopy, for example, multiple two-dimensional images may be generated during performance of step 1014. Performance of this step 1016 may then include measuring a dimension of the body vessel in each of the images and processing the resulting multiple dimensions, for example, by calculating an average of the multiple dimensions, to provide a sizing dimension of the body vessel in the region of interest within the body vessel.

[0058] In method 1000, steps 1010, 1012, 1014, and 1016 may be repeated any desired number of times, as represented by optional step 1018. Repeating steps 1010, 1012, 1014, and 1016 may be advantageous when it is desirable to determine multiple dimensions or sizing pressures of a body vessel. If step 1018 is included, the sizing pressure in each cycle of steps 1010, 1012, 1014, and 1016 may be the same or different from the sizing pressure of the previous cycle of steps 1010, 1012, 1014, and 1016. Using different sizing pressures in subsequent cycles of steps 1010, 1012, 1014, and 1016 is advantageous because at least completion of the method in which different target pressures are used provides multiple dimensions of the body vessel at different target pressures, allowing for determination of sizing pressures, and therefore sizing dimensions, or evaluation of body vessels in different target areas.

[0059] Completion of the method provides a dimension that is a sizing dimension of the body vessel in the region of interest within the body vessel.

[0060] 5 illustrates another example method 1100 for determining sizing dimensions of a body vessel in a region of interest in the body vessel. Method 1100 is similar to method 1000 described above and illustrated in FIG. 4, except as detailed below.

[0061] An initial step 1110 includes positioning a pressurizing device within a body vessel at the region of interest. Another step 1112 includes using the pressurizing device to apply a sizing pressure to an interior surface of the body vessel at the region of interest within the body vessel. Another step 1114 includes maintaining the sizing pressure against the interior surface of the body vessel at the region of interest. Another step 1116 includes generating a visual representation of the region of interest showing a portion of the pressurizing device within the region of interest of the body vessel. Another step 1118 includes measuring dimensions on the visual representation to provide sizing dimensions of the body vessel at the region of interest within the body vessel.

[0062] Step 1110 of positioning a pressurization device within a body vessel in the region of interest can be performed using a variety of devices and techniques, including a sizing catheter, e.g., a catheter including a compliant balloon. Positioning can be performed using a technique appropriate for the pressurization device used in step 1110. For example, if a sizing catheter is used, the sizing catheter can be inserted into an opening into the body vessel and moved into the body vessel to navigate the balloon to the region of interest. In this example, navigation can be performed over a previously placed guidewire or without the aid of a guidewire.

[0063] Step 1112, which uses a pressurization device to apply the sizing pressure, may be performed using a technique suitable for the pressurization device used in step 1110. For example, if a sizing catheter is used in step 1110, step 1112 may be performed by inflating a balloon to a target pressure that applies the sizing pressure to the interior surface of the body vessel in the target area. The pressure to which the balloon is inflated may be the sizing pressure or may be different from the sizing pressure because not all of the balloon inflation pressure may be transmitted to the interior surface of the body vessel.

[0064] Step 1114 of maintaining a sizing pressure against the interior surface of the body vessel may be performed similarly to step 1012 of method 1000 as described above.

[0065] Step 1116 of generating a visual representation of the region of interest may be performed similarly to step 1014 of method 1000 as described above, except as described below. In this method 1100, step 1116 is performed such that at least a portion of the pressurizing device used in step 1010 is shown in the visual representation. For example, if the pressurizing device includes a sizing catheter, step 1116 is performed such that at least the balloon of the sizing catheter is shown in the visual representation. Advantageously, step 1116 of generating a visual representation of the region of interest is performed while step 1014 of maintaining a sizing pressure against the surface of a body vessel in the region of interest is being performed. This timing relationship between the performance of steps 1114, 1116 ensures that step 1118 of measuring a dimension on the visual representation provides a sizing dimension of the body vessel in the region of interest while a sizing pressure is maintained against the interior surface of the body vessel in the region of interest.

[0066] Step 1118 of measuring a dimension on the visual representation may be performed similarly to step 1016 of method 1000 as described above, except as described below. In this method 1100, the dimension may be either a dimension of a body vessel, such as the inner diameter of the body vessel in a plane perpendicular to the axis of the body vessel in the region of interest, the inner diameter of the body vessel in a plane that is not perpendicular to the axis of the body vessel in the region of interest, or a dimension of a pressurizing device, such as the inflated balloon width measured in a plane perpendicular to the axis of the body vessel in the region of interest, in a plane perpendicular to the axis of the sizing catheter along the length of the balloon, or in a plane perpendicular to the axis of the body vessel in the region of interest and perpendicular to the axis of the sizing catheter along the length of the balloon.

[0067] In method 1100, steps 1112, 1114, 1116, and 1118 may be repeated any desired number of times, as represented by optional step 1120. Repeating steps 1112, 1114, 1116, and 1118 may be advantageous if it is desired to determine multiple dimensions of the body vessel. If step 1120 is included, the sizing pressure for each cycle of steps 1112, 1114, 1116, and 1118 may be the same or different from the sizing pressure for the previous cycle of steps 1112, 1114, 1116, and 1118. Using different sizing pressures in subsequent cycles of steps 1112, 1114, 1116, and 1118 is advantageous because completion of the method in which at least different target pressures are used provides multiple dimensions of the body vessel at different target pressures, allowing for determination of sizing pressures, and therefore sizing dimensions, or assessment of body vessels in different target regions.

[0068] Completion 1100 of the method provides one or more dimensions, each of which is a dimension of the body vessel at a region of interest within the body vessel.

[0069] 6 illustrates another example method 1200 for determining sizing dimensions of a body vessel in a region of interest in the body vessel. Method 1200 represents a specific application of method 1000 described above and illustrated in FIG.

[0070] An initial step 1210 includes navigating a sizing catheter having a compliant balloon through a body vessel to a region of interest within the body vessel. Another step 1212 includes inflating the compliant balloon to a target pressure to apply a corresponding sizing pressure against the interior surface of the body vessel at the region of interest. Another step 1214 includes maintaining the target pressure on the compliant balloon. Another step 1216 includes generating a visual representation of the region of interest showing the inflated compliant balloon within the body vessel at the region of interest. Another step 1218 includes measuring dimensions of the inflated compliant balloon on the visual representation to provide sizing dimensions of the body vessel at the region of interest within the body vessel.

[0071] Advantageously, step 1216 of generating a visual representation of the region of interest is performed while step 1214 of maintaining inflation pressure in the balloon over the region of interest is performed. This timing relationship between the performance of these steps 1214, 1216 ensures that step 1218 of measuring the dimensions of the inflated compliant balloon on the visual representation provides the dimensions of the body vessel over the region of interest while inflation pressure is maintained in the balloon over the region of interest.

[0072] Method 1200 is particularly advantageous for implementation in relatively compliant body vessels, such as veins and lymphatic vessels. The method utilizes a sizing catheter having a compliant balloon. Furthermore, the compliant balloon applies a sizing pressure against the interior surface of the body vessel for a particular inflation pressure within the balloon. The sizing pressure for any given inflation pressure may be equal to or less than the inflation pressure and may be empirically determined for a particular inflation pressure or over a range of inflation pressures. Alternatively, a balloon may be used for which one or more pressures have been determined by another, e.g., the manufacturer of the sizing catheter. Alternatively, a balloon may be used for which a relationship between one or more balloon volumes and one or more sizing pressures has been determined empirically or otherwise, e.g., the manufacturer of the sizing catheter.

[0073] In method 1200, steps 1212, 1214, 1216, and 1218 may be repeated any desired number of times, as represented by optional step 1220. Repeating steps 1212, 1214, 1216, and 1218 may be advantageous for determining a sizing dimension if it is desired to determine multiple dimensions of the body vessel. When step 1220 is included, the sizing pressure for each cycle of steps 1212, 1214, 1216, and 1218 may be the same or different from the sizing pressure for the previous cycle of steps 1212, 1214, 1216, and 1218. Using a different sizing pressure in subsequent cycles of steps 1212, 1214, 1216, and 1218 may be advantageous due to completion of the method in which a different target pressure is used to provide at least a sizing pressure and therefore a sizing dimension of the body vessel.

[0074] Determining one or more dimensions of a body vessel based on pressure applied to the interior surface of the body vessel may be part of other methods, such as methods of implanting an intraluminal medical device, methods of fabricating an intraluminal medical device, etc.

[0075] Thus, methods are provided for implanting an intraluminal medical device in a target region within a body vessel. Figures 7, 8, 9, and 10 each illustrate an example method according to this aspect of the invention. Implementation of these and other methods according to this aspect of the invention results in implantation of an appropriately sized intraluminal medical device to prevent migration after measuring a sizing dimension on a visual representation of the body vessel while a sizing pressure is maintained against the interior surface of the body vessel and confirming that the sizing dimension is within a range of desired treatment dimensions for the intraluminal medical device. In some example methods, such as method 2000 shown in Figure 7 and described below, the sizing dimension is a dimension of the body vessel, such as the orthogonal inner diameter of the body vessel. In other example methods, such as method 2200 shown in Figure 9 and described below, the dimension is a dimension of a pressurizing device, such as a compliant balloon of a sizing catheter, positioned within the body vessel as part of implementation of the method.

[0076] An example method for implanting an intraluminal medical device in a target region within a body vessel includes measuring a sizing dimension on a visual representation of the body vessel while a sizing pressure is maintained against the interior surface of the body vessel in the target region, and verifying that the sizing dimension is within a range of desired treatment dimensions, followed by implanting the intraluminal medical device on the interior surface of the body vessel. In some examples, the sizing dimension is a dimension of the body vessel, such as an orthogonal inner diameter of the body vessel, measured while a sizing pressure is maintained against the interior surface of the body vessel in the target region. In other examples, the sizing dimension is a dimension of a pressurizing device used in the method for applying and maintaining a sizing pressure against the interior surface of the body vessel.

[0077] FIG. 7 illustrates an example method 2000 for implanting an intraluminal medical device in a target region within a body vessel. Method 2000 is similar to method 1000 illustrated in FIG. 4, adding steps 2018 and 2020 necessary for implanting an intraluminal medical device. Accordingly, an initial step 2010 includes applying a sizing pressure to an inner surface of a body vessel at a target region within the body vessel. Another step 2012 includes maintaining the sizing pressure against the inner surface of the body vessel at the target region. Another step 2014 includes generating a visual representation of the target region. Another step 2016 includes measuring dimensions of the body vessel at the target region on the visual representation to provide sizing dimensions for the body vessel at the target region within the body vessel. Optionally, another step 2018 includes verifying that the sizing dimensions of the body vessel provided by step 2016 are within a range of treatment dimensions for the intraluminal medical device. Another step 2020 includes implanting an intraluminal medical device adapted to maintain a sizing dimension inside the body vessel.

[0078] Advantageously, step 2014 of generating a visual representation of the region of interest is performed while step 2012 of maintaining a sizing pressure against the surface of the body vessel in the region of interest is being performed. This time relationship between the performance of steps 2012, 2014 ensures that step 2016 of measuring a dimension on the visual representation provides a sizing dimension of the body vessel in the region of interest while a sizing pressure is maintained against the interior surface of the body vessel in the region of interest.

[0079] In step 2018, if included, the range of treatment dimensions for the intraluminal medical device may comprise a range based on previous performance of the method, a known or expected value, or other suitable source.

[0080] Any suitable intraluminal medical device may be used in the performance of step 2020. The device need only be biocompatible and capable of being implanted in a body vessel of the same nature as the body vessel in which the method is being performed. The specific type, size, and configuration of the intraluminal medical device used in step 2020 in a particular method will depend on various considerations, including the nature of the body vessel and the desired results of the method. Examples of types of intraluminal medical devices that may be used in the performance of step 2020 include, but are not limited to, stents, stent grafts, valve devices such as prosthetic venous valves and prosthetic heart valves, filters, occluders, distal protection devices, and other implantable intraluminal medical devices. Intraluminal medical devices including self-expanding support frames, such as self-expanding stents, valve devices including self-expanding support frames, and other intraluminal medical devices including self-expanding frames are considered particularly advantageous for inclusion in the performance of step 2020.

[0081] Step 2020 may be performed using conventional techniques for implanting the particular intraluminal medical device used in step 2020, including any ancillary equipment necessary or desirable to implant the intraluminal medical device. For example, the intraluminal medical device may be navigated to the region of interest within the body vessel on a delivery catheter using conventional insertion and navigation techniques, and then deployed from the delivery catheter using conventional techniques appropriate for the intraluminal medical device and delivery catheter.

[0082] FIG. 8 illustrates another example method 2100 of implanting an intraluminal medical device in a target region within a body vessel. Method 2100 is similar to method 1100 illustrated in FIG. 5 , adding steps 2020 and 2022 necessary to implant an intraluminal medical device. Accordingly, an initial step 2110 includes positioning a pressurizing device within a body vessel in the target region. Another step 2112 includes using the pressurizing device to apply a sizing pressure to the interior surface of the body vessel in the target region within the body vessel. Another step 2114 includes maintaining the sizing pressure against the interior surface of the body vessel in the target region. Another step 2116 includes generating a visual representation of the target region showing a portion of the pressurizing device within the target region of the body vessel. Another step 2118 includes measuring dimensions on the visual representation to provide sizing dimensions of the body vessel in the target region within the body vessel. Another optional step 2120 includes verifying that the sizing dimension of the body vessel provided by step 2118 is within a range of therapeutic dimensions of the intraluminal medical device. Another step 2122 includes implanting the intraluminal medical device adapted to maintain the sizing dimension on the interior surface of the body vessel.

[0083] Advantageously, step 2116 of generating a visual representation of the region of interest is performed while step 2114 of maintaining a sizing pressure against the surface of the body vessel in the region of interest is performed. This time relationship between the performance of these steps 2114, 2116 ensures that step 2118 of measuring a dimension on the visual representation provides a sizing dimension of the body vessel in the region of interest while a sizing pressure is maintained against the interior surface of the body vessel in the region of interest.

[0084] As with step 2020 of method 2000 shown in FIG. 8, any suitable intraluminal medical devices and techniques may be used in performing step 2122, including any desired or necessary ancillary devices.

[0085] FIG. 9 illustrates another example method 2200 for implanting an intraluminal medical device in a target region within a body vessel. Method 2200 is similar to method 1200 illustrated in FIG. 6 , adding steps 2220 and 2222 necessary for implanting an intraluminal medical device. Accordingly, an initial step 2210 includes navigating a sizing catheter having a compliant balloon through a body vessel to a target region within the body vessel. Another step 2212 includes inflating the compliant balloon to a target pressure to apply a corresponding sizing pressure against the interior surface of the body vessel at the target region. Another step 2214 includes maintaining the target pressure on the compliant balloon. Another step 2216 includes generating a visual representation of the target region showing the inflated compliant balloon within the body vessel at the target region. Another step 2218 includes measuring the dimensions of the inflated compliant balloon on the visual representation to provide sizing dimensions of the body vessel at the target region within the body vessel. Another optional step 2220 includes verifying that the sizing dimension of the body vessel provided by step 2218 is within a range of therapeutic dimensions for the intraluminal medical device. Another step 2222 includes implanting the intraluminal medical device adapted to maintain the sizing dimension on the interior surface of the body vessel.

[0086] Advantageously, step 2216 of generating a visual representation of the region of interest is performed while step 2214 of maintaining a sizing pressure against the surface of a body vessel in the region of interest is performed. This time relationship between the performance of these steps 2214, 2216 ensures that step 2218 of measuring a dimension on the visual representation provides a dimension that is a sizing dimension of a body vessel in the region of interest while a sizing pressure is maintained against the interior surface of the body vessel in the region of interest.

[0087] As with step 2120 of method 2100 shown in FIG. 8, any suitable intraluminal medical devices and techniques may be used in performing step 2222, including any desired or necessary ancillary devices.

[0088] 10 illustrates another example method 3000 of implanting an intraluminal medical device in a target region within a body vessel. The method includes multiple steps of measuring dimensions on a visual representation of the target region of the body vessel, each of which is performed while a different sizing pressure is maintained against the interior surface of the body vessel at the target region. Including these multiple measurement steps allows for the generation of curvatures of sizing pressures and corresponding measured dimensions, which are used in selecting a desired dimension, which is then used in identifying the corresponding pressure. Finally, an intraluminal medical device adapted to maintain a desired dimension on the interior surface of the body vessel is implanted in the target region within the body vessel.

[0089] Method 3000 is similar to method 2000 shown in FIG. 7 , but includes additional steps. Accordingly, initial step 3010 includes applying a first sizing pressure to the interior surface of the body vessel at a region of interest within the body vessel. Another step 3012 includes maintaining the sizing pressure on the interior surface of the body vessel at the region of interest. Another step 3014 includes generating a visual representation of the region of interest. Another step 3016 includes measuring a dimension of the body vessel at the region of interest on the visual representation to provide a sizing dimension of the body vessel at the region of interest within the body vessel. Another step 3018 includes repeating steps 3010, 3012, 3014, and 3016 using a second sizing pressure different from the first sizing pressure. Another step 3020 includes generating a curve using the first and second target pressures and the corresponding first and second sizing dimensions. Another step 3022 includes selecting a desired dimension on the curve. Another step 3024 includes identifying a pressure corresponding to the desired dimension for the curve. Another step 3026 includes implanting an intraluminal medical device adapted to maintain the desired dimension on the interior surface of the body vessel at a target region within the body vessel. The cycle of steps 3010, 3012, 3014, and 3016 may be repeated any suitable number of times, including 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or more times, in step 3018. In each cycle of steps 3010, 3012, 3014, and 3016, the same or a different sizing pressure should be used as in the previous cycle, so long as at least two different target pressures are used throughout the entire cycle of steps 3010, 3012, 3014, and 3016. Advantageously, a different sizing pressure is used in each cycle of steps 3010, 3012, 3014, and 3016.

[0090] In some examples, step 3018, i.e., repeating steps 3010, 3012, 3014, and 3016, is performed using a constant increase in sizing pressure throughout step 3010 of applying the sizing pressure performed in performing step 3018. In some examples, step 3018 is performed until such a constant increase in sizing pressure applied in step 3010 in a cycle, compared to the sizing pressure applied in step 3010 in the immediately preceding cycle, results in an increase in the dimension of the body vessel measured in step 3016 in a cycle, compared to the dimension of the body vessel measured in step 3016 in the immediately preceding cycle, of less than about 20% of the dimension of the body vessel measured in step 3016 in the immediately preceding cycle. In some examples, step 3018 is performed until such a constant increase in sizing pressure applied in step 3010 in a cycle, compared to the sizing pressure applied in step 3010 in the immediately preceding cycle, results in an increase in the dimension of the body vessel measured in step 3016 in a cycle, compared to the dimension of the body vessel measured in step 3016 in the immediately preceding cycle, of less than about 10% of the dimension of the body vessel measured in step 3016 in the immediately preceding cycle. In some examples, step 3018 is performed until such a constant increase in sizing pressure applied in step 3010 in a cycle, compared to the sizing pressure applied in step 3010 in the immediately preceding cycle, results in an increase in the dimension of the body vessel measured in step 3016 in a cycle, compared to the dimension of the body vessel measured in step 3016 in the immediately preceding cycle, of less than about 5% of the dimension of the body vessel measured in step 3016 in the immediately preceding cycle.In some examples, step 3018 is performed until such a constant increase in sizing pressure applied in step 3010 in a cycle, compared to the sizing pressure applied in step 3010 in the immediately preceding cycle, results in an increase in the dimension of the body vessel measured in step 3016 in a cycle, compared to the dimension of the body vessel measured in step 3016 in the immediately preceding cycle, of less than about 2% of the dimension of the body vessel measured in step 3016 in the immediately preceding cycle. In some examples, step 3018 is performed until such a constant increase in sizing pressure applied in step 3010 in a cycle, compared to the dimension of the body vessel measured in step 3016 in the immediately preceding cycle, results in an increase in the dimension of the body vessel measured in step 3016 in a cycle, compared to the dimension of the body vessel measured in step 3016 in the immediately preceding cycle, of less than about 2% but more than about 1% of the dimension of the body vessel measured in step 3016 in the immediately preceding cycle. In some examples, step 3018 is performed until such a constant increase in sizing pressure applied in step 3010 in one cycle compared to the sizing pressure applied in step 3010 in the immediately preceding cycle results in an increase in the dimension of the body vessel measured in step 3016 in one cycle of less than about 1% of the dimension of the body vessel measured in step 3016 in the immediately preceding cycle compared to the dimension of the body vessel measured in step 3016 in the immediately preceding cycle.

[0091] Advantageously, for each cycle of steps 3010, 3012, 3014, and 3016, step 3014 of generating a visual representation of the region of interest is performed while step 3012 of maintaining a sizing pressure against the surface of the body vessel in the region of interest is being performed. This time relationship of the performance of these steps 3012, 3014 ensures that step 3016 of measuring a dimension on the visual representation provides a dimension that is a sizing dimension of the body vessel in the region of interest while a sizing pressure is maintained against the interior surface of the body vessel in the region of interest.

[0092] As with step 2020 in method 2000 shown in FIG. 7, any suitable intraluminal medical devices and techniques, including any desired or necessary ancillary devices, may be used in performing step 3026.

[0093] 11 illustrates an example method 4000 for fabricating an intraluminal medical device. An initial step 4010 includes applying a sizing pressure to an inner surface of a body vessel at a region of interest within the body vessel. Another step 4012 includes maintaining the sizing pressure on the inner surface of the body vessel at the region of interest. Another step 4014 includes generating a visual representation of the region of interest. Another step 4016 includes measuring dimensions of the body vessel at the region of interest on the visual representation to provide sizing dimensions for the body vessel at the region of interest within the body vessel. Another step 4018 includes fabricating an intraluminal medical device adapted to maintain the sizing dimensions of the inner surface of the body vessel at the region of interest within the body vessel.

[0094] Advantageously, step 4014 of generating a visual representation of the region of interest is performed while step 4012 of maintaining a sizing pressure against the surface of the body vessel in the region of interest is being performed. This time relationship between the performance of steps 4012, 4014 ensures that step 4016 of measuring a dimension on the visual representation provides a sizing dimension of the body vessel in the region of interest while a sizing pressure is maintained against the interior surface of the body vessel in the region of interest.

[0095] 12 illustrates an example method 5000 for fabricating a plurality of intraluminal medical devices. An initial step 5010 includes applying a first sizing pressure to an inner surface of a body vessel at a region of interest within the body vessel. Another step 5012 includes maintaining the first sizing pressure on the inner surface of the body vessel at the region of interest. Another step 5014 includes generating a visual representation of the region of interest. Another step 5016 includes measuring dimensions of the body vessel at the region of interest on the visual representation to provide sizing dimensions of the body vessel at the region of interest within the body vessel. Another step 5018 includes repeating steps 5010, 5012, 5014, and 5016 using a second sizing pressure different from the first sizing pressure. Another step 5020 includes generating a curve using the first and second sizing pressures and corresponding first and second sizing dimensions. Another step 5022 includes fabricating a first intraluminal medical device adapted to maintain a first dimension in a curve in a body vessel in the region of interest. Another step 5024 includes fabricating a second intraluminal medical device adapted to maintain a second dimension in a curve in a body vessel in the region of interest.

[0096] The cycle of steps 5010, 5012, 5014, and 5016 may be repeated any suitable number of times in step 5018, including 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or more times. In each cycle of steps 5010, 5012, 5014, and 5016, the same or a different sizing pressure should be used as in the previous cycle, so long as at least two different target pressures are used across all cycles of steps 5010, 5012, 5014, and 5016. Advantageously, a different sizing pressure is used in each cycle of steps 5010, 5012, 5014, and 5016.

[0097] Advantageously, for each cycle of steps 5010, 5012, 5014, and 5016, step 5014 of generating a visual representation of the region of interest is performed while step 5012 of maintaining a sizing pressure against the surface of the body vessel in the region of interest is being performed. This timing relationship of the performance of these steps 5012, 5014 ensures that step 5016 of measuring a dimension on the visual representation while the inflation pressure of the sizing catheter is maintained against the interior surface of the body vessel in the region of interest provides a dimension that is a sizing dimension of the body vessel in the region of interest. [Example]

[0098] FIG. 16 shows a simulated pressure-diameter curve ("Simulation"), a pressure-diameter curve based on experimental data acquired using the methods described herein ("Study Data"), and a pressure-diameter curve based on experimental data acquired using IVUS ("IVUS, Breath Hold" and "IVUS, Abdominal Comp").

[0099] Table I below provides vascular sizing measurements obtained using each of the listed sizing methods in two cases. The measurements demonstrate the relative variability of sizing measurements obtained using traditional sizing methods (IVUS, Standing Duplex Ultrasound, and IVUS with Valsalve) compared to the consistent sizing measurements obtained using the method described herein (sizing catheter at set pressure).

[0100] [Table 1]

[0101] Those skilled in the art will understand that, in light of the entire teachings of this disclosure, various modifications and alternatives to the examples described and illustrated may be developed, and that various elements and features of one example described and illustrated herein may be combined with various elements and features of another example without departing from the scope of the invention. Accordingly, the specific examples disclosed herein have been selected by the inventors merely to describe and illustrate examples of the invention, and are not intended to limit the scope of the invention or its protection, which scope is given in full scope of the appended claims, including all claims made in all prosecution-related applications, and any and all equivalents thereof.

Claims

1. 1. A method for determining sizing dimensions of a body vessel at a region of interest in the body vessel, comprising: navigating a sizing catheter having a compliant balloon through a body vessel to the region of interest within the body vessel; inflating the compliant balloon to a target pressure to apply a corresponding sizing pressure against the interior surface of the body vessel in the target area; maintaining the target pressure on the compliant balloon; generating a visual representation of the region of interest showing the inflated compliant balloon within the body vessel in the region of interest; and measuring dimensions of the inflated compliant balloon on the visual representation to provide sizing dimensions of the body vessel at the region of interest within the body vessel; A method comprising:

2. The method of claim 1 , wherein generating the visual representation of the region of interest is performed while maintaining the sizing pressure against the surface of the body vessel in the region of interest is performed.

3. 10. The method of claim 1, wherein generating the visual representation of the region of interest is performed using one of radiography, x-ray computed tomography, x-ray fluoroscopy, venography, ultrasound, and magnetic resonance imaging.

4. The method of claim 1 , wherein the visual representation comprises one of an image recorded on film and a digital still image.

5. The method of claim 1 , wherein the visual representation comprises a series of digital still images.

6. The method of claim 1 , wherein the visual representation comprises a digital video.

7. the body vessel includes a vein; and The method of claim 1 , wherein generating the visual representation of the region of interest comprises injecting a contrast agent into the balloon.

8. 1. A method of implanting an intraluminal medical device in a target region within a body vessel, comprising: applying a first sizing pressure to an interior surface of the body vessel at a target area within the body vessel; maintaining the first sizing pressure against the interior surface of the body vessel in the target area; generating a first visual representation of the region of interest; measuring a first dimension of the body vessel at the region of interest on the visual representation to provide a first measured dimension of the body vessel at the region of interest within the body vessel; applying a second sizing pressure to the interior surface of the body vessel at the target area within the body vessel, the second sizing pressure being different from the first sizing pressure; maintaining the second sizing pressure against the interior surface of the body vessel in the target area; generating a second visual representation of the region of interest; measuring a second dimension of the body vessel at the region of interest on the second visual representation to provide a second measured dimension of the body vessel at the region of interest within the body vessel; generating a curvature using the first and second sizing pressures and the corresponding first and second measured dimensions; selecting a sizing dimension on the curved portion; and implanting an intraluminal medical device adapted to maintain said sizing dimension within said body vessel at said target region within said body vessel. A method comprising:

9. 9. The method of claim 8, wherein each of the steps of generating a visual representation of the region of interest is performed while a corresponding step of maintaining the sizing pressure on the surface of the body vessel in the region of interest is being performed.

10. 9. The method of claim 8, wherein each of the steps of applying a first sizing pressure to the inner surface of the body vessel and applying a second sizing pressure to the inner surface of the body vessel is performed using a sizing catheter having a compliant balloon.

11. the body vessel includes a vein; and The method of claim 10 , wherein generating a first visual representation of the region of interest and generating a second visual representation of the region of interest each include injecting a contrast agent into the balloon.

12. 9. The method of claim 8, wherein each of the steps of generating a first visual representation of the region of interest and generating a second visual representation of the region of interest is performed using one of radiography, x-ray computed tomography, x-ray fluoroscopy, venography, ultrasound, and magnetic resonance imaging.

13. 9. The method of claim 8, wherein each of the first visual representation and the second visual representation comprises one of an image recorded on film and a digital still image.

14. The method of claim 8 , wherein the first visual representation and the second visual representation each comprise a series of digital still images.

15. The method of claim 8 , wherein each of the first visual representation and the second visual representation comprises a digital video.

16. 1. A method of making a plurality of intraluminal medical devices, comprising: applying a first sizing pressure to an interior surface of the body vessel at a target area within the body vessel; maintaining the first sizing pressure against the interior surface of the body vessel in the target area; generating a first visual representation of the region of interest; measuring a first dimension of the body vessel at the region of interest on the visual representation to provide a first measured dimension of the body vessel at the region of interest within the body vessel; applying a second sizing pressure to the interior surface of the body vessel at the target area within the body vessel, the second sizing pressure being different from the first sizing pressure; maintaining the second sizing pressure against the interior surface of the body vessel in the target area; generating a second visual representation of the region of interest; measuring a second dimension of the body vessel at the region of interest on the second visual representation to provide a second measured dimension of the body vessel at the region of interest within the body vessel; generating a curvature using the first and second sizing pressures and the corresponding first and second measured dimensions; selecting a first target pressure for the curved portion; selecting a second target pressure for the curved portion; creating a first intraluminal medical device adapted to apply the first target pressure against an interior surface of the body vessel; and creating a second intraluminal medical device adapted to apply the second target pressure against an interior surface of the body vessel; A method comprising:

17. generating a first visual representation of the target area while maintaining the first sizing pressure against the interior surface of the body vessel in the target area; and 17. The method of claim 16, wherein the step of generating a second visual representation of the target area is performed while the step of maintaining the second sizing pressure against the interior surface of the body vessel in the target area is performed.

18. 18. The method of claim 17, wherein each of the steps of applying a first sizing pressure to the inner surface of the body vessel and applying a second sizing pressure to the inner surface of the body vessel is performed using a sizing catheter having a compliant balloon.

19. the body vessel includes a vein; and 20. The method of claim 18, wherein generating a first visual representation of the region of interest and generating a second visual representation of the region of interest each comprise injecting a contrast agent into the balloon.

20. 17. The method of claim 16, wherein each of the steps of generating a first visual representation of the region of interest and generating a second visual representation of the region of interest is performed using one of radiography, x-ray computed tomography, x-ray fluoroscopy, venography, ultrasound, and magnetic resonance imaging.

Images