WO2013116560A1

WO2013116560A1 - Tissue sampling devices, methods, and systems

Info

Publication number: WO2013116560A1
Application number: PCT/US2013/024214
Authority: WO
Inventors: Amrita SETHI
Original assignee: The Trustees Of Columbia University In The City Of New York
Priority date: 2012-01-31
Filing date: 2013-01-31
Publication date: 2013-08-08

Abstract

Sampling devices, methods, and systems allow cells to be recovered from a body lumen or cavity. In embodiments, an expandable balloon has a surface with features adapted for scraping the surface of the body cavity or lumen. The balloon may be expanded to force its surface against the lumen or cavity surface and the balloon moved by an operator to scour, scrape, or ablate the body lumen or cavity surface. The balloon may be carried in a catheter in a collapsed state and deployed before inflation at the site at which cells are to be recovered. After harvesting, the balloon may be deflated and withdrawn into the catheter near the site of cells harvesting and the catheter withdrawn. This may retrieve the harvested cells and prevent cross- contamination by enclosing the balloon.

Description

TISSUE SAMPLING DEVICES, METHODS, AND SYSTEMS

BACKGROUND

Balloon catheters are known as tools for dilating body lumens such as blood vessels and biliary ducts. Balloon catheters are commonly used to dilate or remove constrictions in lumens or to expand stents or other devices within body channels such as the stomach or the intestines. The balloon catheter may be inserted within the patient and navigated through the channel to a target. The balloon at the distal end of the catheter is inflated using a fluid or air. This causes the balloon to expand until a predefined result is achieved. Once the result is achieved, the balloon may be deflated and removed.

Balloon catheters may be of a variety of constructions which may depend on the application. For example, elastomeric balloon materials such as latex or silicone may be used. Other balloons have a multilayered structure including fibrous materials to limit the magnitude of dilation, provide high tolerance to pressure, and control the shape (e.g., cylinder). Composite balloons may be of flexible but inelastic construction.

Brush sampling catheters are known. In prior art devices, a catheter with a brush inside is insertable in a body lumen and extendable axially from the catheter so that the bristles directly contact the wall of the body lumen. The brush may be moved to collect material. Also known are brush catheters that are inserted into a lumen without a catheter, for example a brush attached to the end of a wire.

SUMMARY

Balloon catheter devices, methods, and systems are described which allow cells to be recovered from a body lumen or cavity. In embodiments, an expandable balloon has a surface with features adapted for scraping the surface of the body cavity or lumen. The balloon may be expanded to force its surface against the lumen or cavity surface and the balloon moved by an operator to scour, scrape, or ablate the body lumen or cavity surface. The balloon may be carried in a catheter in a collapsed state and deployed before inflation at the site at which cells are to be recovered. After harvesting, the balloon may be deflated and withdrawn into the catheter near the site of cells harvesting, and the catheter may be withdrawn. This may retrieve the harvested cells and prevent cross-contamination by enclosing the balloon.

Objects and advantages of embodiments of the disclosed subject matter will become apparent from the following description when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will hereinafter be described in detail below with reference to the accompanying drawings, wherein like reference numerals represent like elements. The accompanying drawings have not necessarily been drawn to scale. Where applicable, some features may not be illustrated to assist in the description of underlying features.

Fig. 1 shows a wire guided catheter with a collapsed balloon inside, according to embodiments of the disclosed subject matter.

Fig. 2 shows a wire guided catheter with a collapsed balloon extended outside the catheter, according to embodiments of the disclosed subject matter.

Fig. 3 shows a wire guided catheter with a collapsed balloon extended outside the catheter and inflated, according to embodiments of the disclosed subject matter.

Figs. 4, 5, and 6 show a wire guided catheter in successive stages of use in which it is inflated and used to scrape the lining of a body lumen, collapsed in preparation for withdrawal, and withdrawn into a catheter, respectively, according to embodiments of the disclosed subject matter.

Fig. 7A shows a balloon wall in partial cross-section prior to full inflation, according to embodiments of the disclosed subject matter.

Fig. 7B shows a balloon wall in partial cross-section after full inflation, according to embodiments of the disclosed subject matter.

Figs. 8A and 8B show a surface feature of a portion of a balloon wall before and after inflation, respectively, according to embodiments of the disclosed subject matter.

Figs. 9A and 9B show a surface feature of a portion of a balloon wall before and after inflation, respectively, according to embodiments of the disclosed subject matter.

Figs. 10A and 10B show a surface feature of a portion of a balloon wall before and after inflation, respectively, according to embodiments of the disclosed subject matter.

Figs. 11 A and 1 IB illustrate a folding balloon configuration that isolates abrasive portions from the body lumen when deflated and exposes such portions after inflation, according to embodiments of disclosed subject matter.

Fig. 12 illustrates a feature that may be applied to modify any of the disclosed embodiments in which an ablative surface is located on a certain position of the balloon in order to focus the ablation to only a single portion of the lumen surface, according to embodiments of the disclosed subject matter. Fig. 13 shows a surface portion of a balloon or attachment thereto that has apse-shaped features which may be produced by means of a cutting tool such as to leave sharp edges and recesses, according to embodiments of the disclosed subject matter.

Figs. 14A and 14B shows a balloon in cross-section in collapsed and inflated states, respectively, where an asymmetric configuration is used to protect an ablating portion until inflated, according to embodiments of the disclosed subject matter.

DETAILED DESCRIPTION

Referring to Fig. 1 , a wire-guided catheter 104 houses an inflatable dilating balloon 106 which is externally lined with an ablative surface 1 10, which may be abrasive or otherwise textured material or an integral surface that gives the balloon 106 the ability to scrape the interior surface of a body lumen. Examples of surface materials and structures include bristles, roughened surfaces, Velcro hooks, textile loops (like Velcro loops), and various other structures suitable for scraping such as molded in shell-shapes, potted or adhered grit particles (sandpaper-like), etc. The balloon 106 is supported on a sheath 102 through which the wire guide 108 can pass. In the displayed configuration, the balloon 106 and the catheter 104 that houses it are wire-guided. The balloon may be inflated, as is known in the art, by flowing a fluid or air into the proximal end of the sheath 102.

Fig. 2 shows the balloon 106 extended distally out of the sheath 104. In use, the catheter can be extended to a site, which may be verified by fluoroscopy, and the catheter partially withdrawn as the balloon 106 is extended out of the catheter thereby maintaining the position of the balloon relative to the body lumen. The ablative surface is indicated at 1 10. Fig. 3 shows the balloon 106 after being inflated with the roughened surface in a distended state 1 12. As is known in the art, balloons may be configured from an oriented material such that the expansion is tangential, only. Also, the expansion may be limited by using flexible but inelastic materials to retain a cylindrical shape of the balloon.

Figs. 4, 5, and 6 show the catheter 104 after insertion in a body lumen 119 in successive stages of use. Fig. 4 shows the catheter 104 in position in the body lumen 119 with the balloon 106 deployed. The distended balloon 106 is inflated to apply a pressure to the wall of the lumen 119 and moved back and forth as indicated by arrow 120 to ablate the surface of the body lumen. The ablative surface 122 may be adapted not only to remove cellular material and cells from the surface but also to trap the material on and within the surface for later recovery. For example, apse-shaped features on the surface may have sharp edges for ablating or eroding the surface and may define recesses in which to capture removed material. Small arches with openings facing distally and proximally could also provide that function. Fig. 5 shows the balloon 106 after being used to ablate the lining of the body lumen 119 and subsequently collapsed. In Fig. 6 the balloon 106 is shown withdrawn back into the catheter 104 after which it is withdrawn in order to harvest material removed from the body lumen 119.

In embodiments, the catheter 104 is inserted into the working channel of a duodenoscope during endoscopic retrograde cholangiopancreatography (ERCP) over the wire 108, into the bile duct. The catheter 104 is advanced until it traverses a region of interest, such as a stricture. Radiopaque markers may be incorporated in the balloon or catheter and used to indicate the location of the balloon 106 during this procedure.

The balloon 106 may be initially held in a sheath in which case it is extended beyond the sheath (Fig. 2) and then inflated (Fig. 3) to preset diameters to dilate the stricture. In expanding radially, the abrasive material on the outer surface of the balloon will be pressed forcefully into the tissue and will collect tissue for sampling. The balloon may be moved, vibrated, shifted, rotated or otherwise actuated to facilitate removal of cells (Fig. 4). The balloon is deflated (Fig. 5) and the sheath of the catheter is then advanced over the deflated balloon (or the balloon is retracted) (Fig. 5) and sampled material caught by the surface in order to help retain the specimen for collection and analysis.

The structure and method described herein addresses the poor diagnostic performance of current cytology brush systems in the diagnosis of pancreaticobiliary strictures. Similar details of dilating balloon catheters may be as those available from multiple endoscopic accessory device companies such as Boston Scientific, Cook Medical, Olympus. The combination of a balloon and tissue sampling surface effecter provides for more effective sampling. The balloon provides a radial force to the acquisition material which allows from more positive engagement or abrasive contact with the stricture and increased likelihood of collecting a highly cellular specimen.

The apparatus allows for simultaneous dilation and brushing of a pancreaticobiliary stricture. These are two steps that are typically performed separately and sequentially in the setting of a stricture. By applying radial force and ablative material against the tissue in question, a more cell-rich specimen can be obtained. This may increase the adequacy of the tissue specimen cytologic analysis.

The apparatus may be used by other specialties that perform wire-guided procedures such as but not limited to interventional radiologists, pulmonologists, and urologists. The disclosed subject matter includes diagnostic and therapeutic medical devices that may be used for increased tissue yield in the sampling of pancreaticobiliary strictures. The embodiments incorporate tissue sampling material such as a brush and a dilating balloon. The design allows for simultaneous dilation of the stricture and allows for abrasion of the tissue to achieve greater quantities of cellular material for sampling.

The tissue diagnosis of pancreaticobiliary strictures is of critical importance in allowing for appropriate therapy such as chemotherapy or surgery. Current sampling methods during ERCP include brush cytology, forcep biopsy, and fine needle aspiration. Dilation of benign strictures is a therapeutic practice after performing diagnostic sampling, followed by stent placement. Dilation of malignant strictures may be needed if the stricture is too tight to accommodate sampling devices or therapeutic stents. Using the present apparatus, this may be done at the same time with a single instrument insertion.

The wire-guided catheter may be formed as a dilating balloon which may be made of plastic at the intraductal end. In embodiments, the balloon may be similar to current

commercially available dilating balloon devices. As such, there may be a port on the catheter that will allow for inflation of the balloon to preset diameters. The balloon may have a tissue sampling component such as a band or any other device suitable for ablation. This may be, for example, a band of abrasive material such as bristles or Velcro that will adhere to the outer surface of the balloon. When the balloon is inflated, the tissue collecting component will be pressed into the tissue with radial force, which will allow for increased ablation of the tissue and thereby more cellular specimen. Sampling will be enhanced by small movements of the inflated balloon back and forth within the stricture. An outer sheath may be advanced over the deflated balloon (or the balloon withdrawn). The sheath may also be made of a plastic material.

The surface may be formed by bonding or forming surface features onto the balloon leaving gaps of resilient material for dilation of the balloon. The features may be arrayed along longitudinal elements molded into the balloon or adhesively attached. Non-limiting examples of ablative surface configurations are shown in Figs. 7A through 12.

Referring to Fig. 7 A, a partial cross-section of a balloon 144 is shown with surface features 142 in the form of bumps with small hook shaped protrusions. Fig. 7A shows the balloon deflated, and Fig. 7B shows the balloon inflated. Fig. 8 A shows the features of Fig. 7 A from a radial perspective and showing only a portion of a balloon to illustrate how the features 162 may be arranged in rows. As shown in Fig. 8B, such rows may separate, as indicated at 162, when the balloon expands. The features 162 may be attached to a flexible and elastic material by adhesive. The features may be molded into inelastic strips that are then adhered to an elastic material of the balloon, for example. In this way the expansion would be permitted between the longitudinal strips. Alternatively the balloons may be made of an inelastic material which may fold and the same construction, with longitudinal strips, may permit folding by leaving easily foldable gaps between them. The strips may be formed by disposing them on the balloon with an adhesive potting material containing grit particles, for example. Note that a folding balloon may have diagonal strips (helical) laid on them and the folding pattern may be helical. The latter configuration avoids gaps in the eroded body lumen surface if the balloon is reciprocated in the axial direction without rotation.

Figs. 9A and 9B show another ablative surface embodiment for a balloon. Fig 9A shows a surface of a collapsed balloon surface portion with Velcro hook- like surface features arranged in a hexagonal array. Fig. 9B shows the same balloon surface portion when the balloon is expanded. Figs. 10A and 10B show another ablative surface

embodiment for a balloon. Fig 10A shows a surface of a collapsed balloon surface portion with Velcro hook-like surface features arranged in a hexagonal array and alternating orientations. Fig. 1 OB shows the same balloon surface portion when the balloon is

expanded. In the embodiments of Fig. 9A, 9B and 10A, 10B, hooks can be oriented in an axial direction so that they engage the body lumen surface when the balloon is moved in the axial direction.

Figs. 1 1A and 1 IB show a folding balloon 204 construction with patches or strips of ablative material 202 in a cross-section view. The patches or strips of ablative material 202 are hidden in the folds when the balloon 204 is in the collapsed state so that when the balloon is extended out of the catheter, it does not engage the body lumen until it is inflated, which may make it easier to use in tighter strictures or if there are intermediate obstructions that need to be bypassed. Fig. 11 A shows the folded configuration and Fig. 1 IB shows the inflated configuration.

Fig. 12 shows an inflated balloon 222 with a patch or strip of ablative material 220 asymmetrically located to allow a surface portion of a body lumen on only one side to be ablated.

Fig. 13 shows a surface portion 284 of a balloon or attachment thereto (such as a strip, patch, or the balloon itself) that has apse-shaped features 280. For example, features 280 may be produced by means of a cutting tool with mirror image features that gouge a deformable material to cut into it and raise the apses leave a sharp edges 286 at the top of each apse and recesses 282 proximate the balloon surface 284. In alternative embodiments, the surface features may be raised arches with sharp edges at their peaks and having a channel defined below the arch. In these embodiments, the recess or channel as well as the space between the features may help to hold only material removed from the surface of the body lumen.

Figs. 14A and 14B shows a balloon in cross-section in collapsed and inflated states, respectively, where an asymmetric configuration is used to protect an ablating portion until inflated. Balloon 302 has an ablative portion 306 and is configured to fold such that the ablative portion 306 is hidden until balloon 302 is inflated, facilitating the extension and withdrawal of the balloon as discussed with reference to Figs. 1 1 A and 1 IB.

In methods of using the balloon, the balloon's size may be selected by pumping fluid or air into it according to the measured or predicted size of the body lumen or stricture. For example, the size may be determined by fluoroscopy or diagnostic images obtained prior to a sampling procedure.

According to embodiments, the disclosed subject matter includes a sheath that carries an expandable member, where the expandable member is configured for ablating tissue and has a size that may be selected by an operator or a controller. The size may be selected using an active support system such as a pump that pumps predetermined volumes of fluid or air, or applies predetermined pressure to the fluid or air as it is pumped into the balloon. The range of sizes of the balloon or the range of pressures it exerts on the walls of the body lumen may have an infinite number of steps.

According to first embodiments, the disclosed subject matter includes a tissue sampling method that includes providing a sheath with an expandable member therein. The expandable member can have a scraping surface thereon. The method can include inserting the sheath in a body lumen and exposing the expandable member to the body lumen by moving the sheath and expandable member relative to each other. The method can include controlling a pressure or size of the expandable member inside the body lumen. The method can include moving the expandable member to remove material from inside the body lumen and recovering the material.

Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the moving includes pushing and drawing an elongate shaft along an axis thereof, wherein the elongate shaft is attached to the expandable member. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the expandable member includes a balloon. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the controlling includes controlling a pump to pump fluid or air into the balloon. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the controlling includes selecting a size or pressure responsively to a diagnostic image of said body lumen. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the scraping surface includes oriented projections from the surface of the expandable member. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the scraping surface includes hooks extending from the surface of the expandable member. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the scraping surface includes grit. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the balloon is elastic. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the balloon is inelastic. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the body lumen is a bile duct. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the body lumen includes a stricture. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the grit is attached to the expandable member in a pattern that allows a diameter of the expandable member to increase. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the recovering the material includes drawing the expandable member into the sheath and withdrawing the sheath from the body lumen. Any of the first embodiments may be modified, where possible, to form additional first embodiments in which the body lumen is a bile duct.

According to second embodiments, the disclosed subject matter includes a balloon catheter with an expandable balloon catheter having an external surface with surface features arrayed thereover. Each of the surface features includes at least one sharp portion remote from the balloon surface and a capture region proximate the balloon surface.

According to third embodiments, the disclosed subject matter includes a kit including the balloon catheter according to the second embodiments and further comprising a sheath sized for receiving the balloon in a collapsed configuration and having a distal opening through which the collapsed balloon can be extended out of the sheath.

According to fourth embodiments, the disclosed subject matter includes a tissue sampling device with a sheath having an expandable member therewithin, the expandable member and sheath being configured to permit the expandable member to be extended out of the catheter in an axial direction. The expandable member has a size that is actively selectable over range with an infinite number of steps. The expandable member has a surface configured to interferingly engage and ablate the tissue of a host thereby to remove and capture cells of the host. The expandable member is configured to be expanded so as to dilate a lumen in the host thereby expanding the lumen and pressing the surface elements into the host tissue. The expandable member is further configured to collapse and to be withdrawn into the catheter to recover the cells.

Any of the fourth embodiments may be modified, where possible, to form additional fourth embodiments in which the expandable member includes an inflatable balloon. Any of the fourth embodiments may be modified, where possible, to form additional fourth embodiments in which the surface elements include an array of hooks, loops, pins, fibers, blades, cups, arches, apses, or other shaped elements that can scratch tissue and remove surface cells from the tissue. Any of the fourth embodiments may be modified, where possible, to form additional fourth embodiments in which the surface elements are in a rectangular array. Any of the fourth embodiments may be modified, where possible, to form additional fourth embodiments in which the surface elements are in a hexagonal array. Any of the fourth embodiments may be modified, where possible, to form additional fourth embodiments in which the surface elements form helical or axial strips on the surface of the balloon.

According to fifth embodiments, the disclosed subject matter includes a method of using the device of the fourth embodiments. The method includes inserting the catheter in a body lumen and actively expanding the expandable member to a predefined size or to exert a predefined pressure on walls of the body lumen. The method includes withdrawing the catheter and recovering cells from the surface elements.

Any of the fifth embodiments may be modified, where possible, to form additional fifth embodiments in which the expanding includes deflating the balloon. Any of the fifth

embodiments may be modified, where possible, to form additional fifth embodiments that include deflating the balloon prior to said withdrawing. Any of the fifth embodiments may be modified, where possible, to form additional fifth embodiments that include drawing the expandable member into the catheter prior to the withdrawing. Any of the fifth embodiments may be modified, where possible, to form additional fifth embodiments that include collapsing the expandable member before withdrawing it.

According to sixth embodiments, the disclosed subject matter includes a balloon catheter with a shaft with an balloon on an end thereof, the shaft being connected to a mechanism for pumping fluid into and out of the balloon to provide a predetermined pressure or volume of the balloon. The balloon has an external surface with surface features arrayed thereover. Each of the surface features includes at least one sharp portion remote from the balloon surface and a capture region proximate the balloon surface. According to further embodiments, a kit includes the balloon catheter of the sixth embodiment and further a sheath that is sized for receiving the balloon in a collapsed configuration and having a distal opening through which the collapsed balloon can be extended out of the sheath.

The foregoing descriptions apply, in some cases, to examples generated in a laboratory, but these examples can be extended to production techniques. For example, where quantities and techniques apply to the laboratory examples, they should not be understood as limiting.

Features of the disclosed embodiments may be combined, rearranged, omitted, etc., within the scope of the invention to produce additional embodiments. Furthermore, certain features may sometimes be used to advantage without a corresponding use of other features.

It is, thus, apparent that there is provided, in accordance with the present disclosure, tissue sampling catheter devices, systems, and methods. Many alternatives, modifications, and variations are enabled by the present disclosure. While specific embodiments have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. Accordingly, Applicant intends to embrace all such alternatives, modifications, equivalents, and variations that are within the spirit and scope of the present invention.

Claims

1. A tissue sampling method, comprising:

providing a sheath with an expandable member therein;

the expandable member having a scraping surface thereon;

inserting the sheath in a body lumen;

exposing the expandable member to the body lumen by moving the sheath and expandable member relative to each other;

controlling a pressure or size of the expandable member inside the body lumen;

moving the expandable member to remove material from inside the body lumen; and recovering the material.

2. The method of claim 1, wherein the moving includes pushing and drawing an elongate shaft along an axis thereof, wherein the elongate shaft is attached to the expandable member.

3. The method of claim 2, wherein the expandable member includes a balloon.

4. The method of claim 3, wherein the controlling includes controlling a pump to pump fluid into the balloon.

5. The method of claim 4, wherein the controlling includes selecting a size or pressure responsively to a diagnostic image of said body lumen.

6. The method of claim 3, wherein the controlling includes selecting a size or pressure responsively to a diagnostic image of said body lumen.

7. The method of claim 2, wherein the controlling includes selecting a size or pressure responsively to a diagnostic image of said body lumen.

8. The method of claim 1, wherein the controlling includes selecting a size or pressure responsively to a diagnostic image of said body lumen.

9. The method of claim 1, wherein the scraping surface includes oriented projections from the surface of the expandable member.

10. The method of claim 1, wherein the scraping surface includes hooks extending from the surface of the expandable member.

11. The method of claim 1 , wherein the scraping surface includes grit.

12. The method of claim 3, wherein the balloon is elastic.

13. The method of claim 3, wherein the balloon is inelastic.

14. The method of claim 1 , wherein the body lumen is a bile duct.

15. The method of claim 1, wherein the body lumen includes a stricture.

16. The method of claim 11, wherein the grit is attached to the expandable member in a pattern that allows a diameter of the expandable member to increase.

17. The method of claim 1, wherein the recovering the material includes drawing the expandable member into the sheath and withdrawing the sheath from the body lumen.

18. The method of claim 17, wherein the body lumen is a bile duct.

19. A balloon catheter, comprising:

an expandable balloon catheter having an external surface with surface features arrayed thereover;

each of the surface features including at least one sharp portion remote from the balloon surface and a capture region proximate the balloon surface.

20. A kit including the balloon catheter of claim 19 and further comprising a sheath sized for receiving the balloon in a collapsed configuration and having a distal opening through which the collapsed balloon can be extended out of the sheath.

21. A tissue sampling device, comprising:

a sheath having an expandable member therewithin, the expandable member and sheath being configured to permit the expandable member to be extended out of the sheath in an axial direction;

the expandable member having a size that is actively selectable over range with an infinite number of steps;

the expandable member having a surface configured to interferingly engage and ablate the tissue of a host thereby to remove and capture cells of the host;

the expandable member being configured to be expanded to dilate a lumen in the host thereby expanding the lumen and pressing the surface elements into the host tissue;

the expandable member being further configured to collapse and to be withdrawn into the sheath to recover the cells.

22. The device of claim 21 , wherein the expandable member includes an inflatable balloon.

23. The device of claim 22, wherein the surface elements include an array of hooks, loops, pins, fibers, blades, cups, arches, apses, or other shaped elements that can scratch tissue and remove surface cells from the tissue.

24. The device of claim 21, wherein the surface elements include an array of hooks, loops, pins, fibers, blades, cups, arches, apses, or other shaped elements that can scratch tissue and remove surface cells from the tissue.

25. The device of claim 24, wherein the surface elements are in a rectangular array.

26. The device of claim 23, wherein the surface elements are in a rectangular array.

27. The device of claim 22, wherein the surface elements are in a rectangular array.

28. The device of claim 21, wherein the surface elements are in a rectangular array.

29. The device of claim 24, wherein the surface elements are in a hexagonal array.

30. The device of claim 23, wherein the surface elements are in a hexagonal array.

31. The device of claim 22, wherein the surface elements are in a hexagonal array.

32. The device of claim 21, wherein the surface elements are in a hexagonal array.

33. The device of claim 22, wherein the surface elements form helical or axial strips on the surface of the balloon.

34. A method of using the device of claim 22, comprising:

inserting the sheath in a body lumen and actively expanding the expandable member to a predefined size or to exert a predefined pressure on walls of the body lumen;

withdrawing the sheath and recovering cells from the surface elements.

35. The method of claim 34, wherein the expanding includes deflating the balloon.

36. The method of claim 35, further comprising deflating the balloon prior to said withdrawing.

37. The method of claim 34, further comprising drawing the expandable member into the sheath prior to the withdrawing.

38. The method of claim 34, further comprising collapsing the expandable member before withdrawing it.

39. A balloon catheter, comprising:

a shaft with an balloon on an end thereof, the shaft being connected to a mechanism for pumping fluid or air into and out of the balloon to provide a predetermined pressure or volume of the balloon;

the balloon having an external surface with surface features arrayed thereover; each of the surface features including at least one sharp portion remote from the balloon surface and a capture region proximate the balloon surface.

40. A kit including the balloon catheter of claim 39, and further comprising a sheath sized for receiving the balloon in a collapsed configuration and having a distal opening through which the collapsed balloon can be extended out of the sheath.

41. The method or device of any one of the above claims, wherein the surface elements constitute an array of at least 100.

42. A tissue sampling device, comprising:

a catheter having an expandable member therewithin, the expandable member and catheter being configured to permit the expandable member to be extended out of the catheter;

the expandable member having a surface configured to interferingly engage and ablate the tissue of a host so as to remove and capture cells of the host;

the expandable member being further configured to collapse and to be

withdrawn into the catheter to recover the cells.

43. The device of claim 42, wherein the expandable member includes an inflatable balloon.

44. The device of claim 43, wherein the surface elements include an array of hooks, loops, pins, fibers, blades, cups, arches, apses, or other shaped elements that can scratch tissue and remove surface cells from the tissue.

45. The device of claim 42, wherein the surface elements include an array of hooks, loops, pins, fibers, blades, cups, arches, apses, or other shaped elements that can scratch tissue and remove surface cells from the tissue.

46. The device of claim 45, wherein the surface elements are in a rectangular array.

47. The device of claim 44, wherein the surface elements are in a rectangular array.

48. The device of claim 43, wherein the surface elements are in a rectangular array.

49. The device of claim 42, wherein the surface elements are in a rectangular array.

50. The device of claim 45, wherein the surface elements are in a hexagonal array.

51. The device of claim 44, wherein the surface elements are in a hexagonal array.

52. The device of claim 43, wherein the surface elements are in a hexagonal array.

53. The device of claim 42, wherein the surface elements are in a hexagonal array.

54. The device of claim 42, wherein the surface elements form helical or axial strips on the surface of the balloon.