Robotic catheter system

A catheter system including a housing and a drive mechanism supported by the housing is provided. The drive mechanism includes an engagement structure configured to engage and to impart movement to a catheter device. The engagement structure defines a path for the catheter device, and the engagement structure is moveable between an engaged position in which the engagement structure engages the catheter device and a disengaged position in which the engagement structure does not engage the catheter device. The catheter system includes a biasing element configured to bias the engagement structure toward the engaged position, and the biasing element is aligned generally parallel to the path defined by the engagement structure.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of robotic catheter systems for performing interventional procedures. One interventional procedure used to treat patients with diseased, often obstructed, heart arteries, is a percutaneous coronary intervention (“PCI”).

Before performing an interventional procedure with the disclosed invention, a diagnostic procedure is typically performed. An exemplary diagnostic procedure performed before performing a PCI may include a number of steps. Starting in the femoral artery, a 0.038 guide wire is run over the top of the aortic arch. A diagnostic catheter is advanced over the 0.038 guide wire after which the 0.038 guide wire is removed allowing the diagnostic catheter (DC) to return to its preformed shape enabling the DC to access either the left or the right ostium of the aorta. A contrast media is injected through the DC and the heart is x-rayed to identify the existence and location of any lesion. A y-connector may be secured to the end of the DC outside of the patient. The y-connector provides a means for introducing the contrast media or medication. The y-connector employs a one way valve both at the y-connector leg and the free open end. The 0.038 guide is then reinserted into the DC advanced over the top of the aortic arch, and the diagnostic catheter is removed. When the diagnostic is completed the 0.038 guide wire may be left in place for use in a PCI procedure.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a robotic catheter system. The catheter system includes a housing and a drive mechanism supported by the housing. The drive mechanism includes an engagement structure configured to engage and to impart movement to a catheter device. The engagement structure defines a path for the catheter device, and the engagement structure is moveable between an engaged position in which the engagement structure engages the catheter device and a disengaged position in which the engagement structure does not engage the catheter device. The catheter system includes a biasing element configured to bias the engagement structure toward the engaged position, and the biasing element is aligned generally parallel to the path defined by the engagement structure.

Another embodiment of the invention relates to a cassette for use with a robotic catheter system. The cassette includes a housing, an axial drive mechanism supported by the housing configured to impart axial movement to a guide wire and a rotational drive mechanism supported by the housing to rotate the guide wire about its longitudinal axis. The rotational drive mechanism includes an engagement structure to releasably engage the guide wire, and the engagement structure is configured to apply sufficient force to rotate the guide wire about a longitudinal axis of the guide wire while permitting the guide wire to be moved axially by the axial drive mechanism. The engagement structure defines a path for the guide wire, and the engagement structure is moveable between an engaged position in which the engagement structure engages the guide wire and a disengaged position in which the engagement structure does not engage the guide wire. The cassette also includes a biasing element configured to bias the engagement structure toward the engaged position. The biasing element is aligned generally parallel to the path defined by the engagement structure.

Another embodiment of the invention relates to a cassette for use with a robotic catheter system. The cassette includes a housing, a first axial drive mechanism supported by the housing to releasably engage and drive a guide wire along a longitudinal axis of the guide wire, a second axial drive mechanism supported by the housing to releasably engage and drive a working catheter along a longitudinal axis of the working catheter, and a rotational drive mechanism supported by the housing to rotate the guide wire about its longitudinal axis. The rotational drive mechanism includes a pivoting structure, a chassis, a channel formed in the chassis for receiving the guide wire, a first wheel coupled to the chassis, and a second wheel coupled to the pivoting structure. The pivoting structure pivots about a pivot point to move the second wheel between an engaged position in which the guide wire is engaged between the first and second wheels and a disengaged position in which the guide wire is not engaged between the first and the second wheels. The rotational drive mechanism includes a first spring biasing the second wheel toward the engaged position, and the first spring is aligned generally parallel to the channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG. 1, a robotic vascular catheter system10is used for performing interventional procedures, including performing a percutaneous coronary intervention (“PCI”). Discussion will proceed assuming a PCI is being performed. It should be noted, however, one skilled in the art would recognize that, although the system described is configured to perform a PCI, it is capable of performing a number of interventional procedures with minor adjustments. For more complex procedures, more than one robotic vascular catheter system10may be used.

Robotic vascular catheter system10comprises a bedside system12and workstation14. The bedside system12comprises a motor controller, an articulating arm18, an arm support20, a motor drive base22, a cassette24, and a guide catheter support26. Guide catheter support may be part of the cassette or alternatively may be a separate component that can be mounted to the cassette. Bedside system12is in communication with workstation14, allowing signals generated by user inputs to workstation14to be transmitted to bedside system12, controlling the various functions of beside system12. Bedside system12also may provide feedback signals to workstation14. Bedside system12may be connected to workstation14with a wireless connection means (not shown), with cable connectors (not shown), or with any other means capable of allowing signals generated by user inputs to workstation14to be transmitted to beside system12.

Workstation14is capable of being remotely located, enabling robotic vascular catheter system10users to perform procedures outside the radiation zone, for instance, in either a procedure room or a separate control room. One benefit of remotely locating workstation14is that the need to wear heavy lead garments may be eliminated. This reduces orthopedic occupational hazards, including, but not limited to, spinal injuries and general strain on the body of the operator. A second benefit of remotely locating workstation14is that the dangers associated with radiation exposure are reduced. A third benefit of remotely locating workstation14is that it allows users to multitask outside the procedure room during downtime.

Bedside system12may be coupled to a standard table side bar (not shown) of a patient's bed28by locking bedside system12relative to a patient30. The front of bedside system12, and correspondingly cassette24, is the end nearest the head of patient30when a procedure is being performed. The back of bedside system12is the end opposite the front. Coupling the bedside system to the bed or proximate the patient may be achieved using methods known in the art, including bolting bedside system12to the standard table side bar or using any other means sufficient to lock bedside system12relative to patient30and/or the bed. Ideally bedside system12is secured in a manner that is quick and easily to install. Bedside system12may be permanently coupled to the standard table side bar throughout numerous procedures, in one embodiment cassette24is replaced for different patients and/or different PCI procedures. However, bedside system12may be removably coupled to a bed for movement from one bed to another.

Cassette24is designed for a single use; it is disposable and should be replaced after each use. Cassette24may include a frangible component (not shown) that breaks off when cassette24is removed from motor drive base22to help ensure that cassette24is used for no more than a single use. Other mechanical means may be used to ensure a single use. For example, a portion of the cassette may be moved or manipulated in a way that does not permit the use of the cassette in another PCI procedure. Alternatively, cassette24may include an RFID (radio frequency identification) system (not shown) to identify when a cassette has been used. The cassette may include an RFID tag or other means of providing descriptive information identifying the type of cassette, particular features as well as a unique identifier for the particular cassette to distinguish it from any other cassette. Other components or systems capable of helping ensure that cassette24is used for no more than a single use may also be alternatively used. The fact that cassette24is designed for a single use has a number of benefits, including, but not limited to, helping maintain a sterility of robotic vascular catheter system10components and prevent patient-to-patient transmission of infections. The RFID system may permit the removal of the cassette for a short defined period of time, to enable resetting of the cassette, if it should fail to be securely attached in the first instance. The system could recognize the unique cassette by its unique identification from the RFID signal and allow the same cassette to be reintroduced only within a very short window of time that would suggest the cassette was being repositioned and not being used for another patient. It is also possible that the cassette may formed from materials that can be sterilized and reused, or certain components may be replaced that come into contact with bodily fluids.

FIG. 2illustrates a preferred embodiment of robotic vascular catheter system10. Articulating arm18is coupled to and protrudes outward from arm support20. Motor drive base22is coupled to articulating arm18. Cassette24is coupled to the top of motor drive base22.

Articulating arm18is configured to be locked into infinite positions relative to patient30. In a preferred embodiment, articulating arm18includes a first knuckle32and a second knuckle34. First knuckle32enables articulating arm18to pivot about a vertical axis and or a horizontal axis. Second knuckle34enables articulating arm18to pivot up and down or about a horizontal axis. Articulating arm18may have multiple degrees of freedom to position cassette24in any orientation relative to the patient for proper positioning. Once the user has adjusted articulating arm18, articulating arm18is locked into place by an articulating arm locking mechanism, preventing unwanted movement during the procedure. Articulating arm locking mechanism may be locked and unlocked mechanically, using a solenoid, or using any other mechanism capable of locking articulating arm18, along with motor drive base22and cassette24, relative to patient30.

Referring toFIG. 3, bedside system12illustrated inFIG. 2is shown before cassette24is attached to motor drive base22. Motor drive base22includes a housing38and a plurality of capstans40. Capstans40extend vertically to facilitate alignment with cassette24when coupling motor drive base22and cassette24. Cassette24includes a housing42, a cover44pivotally attached to housing42, and a plurality of capstan sockets46corresponding to capstans40on motor drive base22to facilitate alignment with motor drive base22when coupling cassette24and motor drive base22. In one embodiment capstans40extend generally upward and are matingly received in capstan sockets46that are located on the bottom surface of cassette24. This permits cassette24to be placed onto motor drive base22in a generally downwardly direction. It is contemplated that motor drive base22and cassette24will be at an angle relative to a horizontal plane in an operative position to direct the guide catheter, guide wire and working catheter in a downwardly sloping direction toward the patient. Capstans40and capstan sockets46are one embodiment of a motor coupler, coupling the motors to axial and rotation drive mechanisms in the cassette. The capstans40and capstan sockets46may have gearing to allow a rotational force to be transmitted from motors located in the motor drive base22to the axial and rotational drive mechanisms within the cassette. While the capstans and capstan sockets allow the cassette to be placed downwardly onto the motor drive base, other motor couplers that can couple the motors to the drive mechanisms are also contemplated. In one embodiment the motors are located in the motor drive base22. However, the motor drive base22may also be used to transmit force from motors located away from the motor drive base that are operatively coupled to the motor drive base with a mechanical linkage such as a cable or other mechanical coupler. It is also contemplated that the mechanical linkage could directly connect the motors to the capstan sockets so that the motor drive base22provides support for the cassette24and permits coupling of the cassette capstan sockets to the motors.

As illustrated inFIG. 2A, cover44may be opened to provide access to the mechanisms within cassette24to help facilitate loading and unloading of the guide wire and catheter instruments within the cassette24. Cover44may include a wall member used to help positively locate the guide wire within the transmission mechanisms as described more fully below. Cover44may be secured by a hinge or other pivot enabling members. Alternatively, cover44may be secured in an up down arrangement. The movement of cover44from a closed to open position may cause the release of the guide wire or other catheter instruments from the transmission mechanisms.

Before coupling cassette24to motor drive base22, a sterile, plastic cover (not shown) is draped over articulating arm18and motor drive base22. The sterile, plastic cover includes pre-cut holes (not shown) that correspond to capstans40on motor drive base22. The sterile, plastic cover shields the sterilized components of robotic vascular catheter system10from the unsterilized components, including motor drive base22, articulating arm18, and arm support20. Cassette24is sterile before use. Once cassette24has been coupled to motor drive base22and used, it is disposed of and replaced with another sterile, single-use cassette.

Referring toFIGS. 6-9, cassette24further includes a first axial drive mechanism48for driving a guide wire50along its longitudinal axis, a second axial drive mechanism52for driving a working catheter54along its longitudinal axis, a first rotational drive mechanism56enabling guide wire50to rotate while still permitting guide wire50to be independently moved along its longitudinal axis. Working catheter54may be embodied as a balloon, stent on a delivery catheter, a stent with a balloon, or any other therapeutic or diagnostic catheter device; these embodiments are collectively referred to as working catheter54. In one embodiment first axial drive mechanism48and first rotational drive mechanism56are positioned substantially in series along a longitudinal axis60of cassette24. In one embodiment, second axial drive mechanism52is positioned at an angle to first axial drive mechanism48.

After coupling cassette24to motor drive base22and before using robotic vascular catheter system10for a procedure, guide wire50and working catheter54must be loaded into the drive mechanisms in cassette24. To load cassette24, the user opens cover44. Upon opening cover44, an engagement-disengagement mechanism is activated, causing the drive mechanisms to automatically adjust for quick access. When cassette24is in open cover position, the drive mechanisms are in position for loading guide wire50and working catheter54. Upon closing cover44, the engagement-disengagement mechanism is activated, causing the drive mechanisms to automatically adjust, releasably engaging guide wire50and working catheter54. Alternatively, it may be possible to engage and/or disengage guide wire50when cover44is in an open position. When cassette24is in closed cover position, the drive mechanisms apply sufficient pressure to guide wire50and working catheter54to be able to drive them. In a preferred embodiment, cover44is formed from a clear, translucent material to permit viewing of the drive mechanisms while cover44is closed, in closed cover position. Though, one of skill in the art would recognize that a variety of other materials are suitable. It may also be possible to disengage the drive mechanisms with a mechanical switch or electromechanical device with or without first opening the cover. Disengagement of the drive mechanisms will result in the surfaces of the pinch rollers of the axial drive mechanisms and the engagement surfaces of the rotational drive mechanism moving away from one another to allow easy removal and insertion of the guide wire and working catheter. At least one of the pinch rollers is supported by at least one disengagement mechanism that physically moves the pinch roller surfaces away from one another. Similarly, the engagement surfaces of the rotational drive mechanism are also operatively connected to a disengagement mechanism to physically move the engagement surfaces of the rotational drive mechanism away from one another. The pinch rollers are in a disengagement position when the pinch roller surfaces are positioned apart from one another.

Cassette24further includes a system to self-test the cassette upon loading (not shown). The system for self-testing cassette loading may be activated by an operator at workstation14. Alternatively, the system may automatically initiate a self-test of the cassette upon closing of cover44to test each of the drive mechanisms. Feedback from the motors to workstation14could confirm proper seating of the cassette within the base. In addition to testing that each of the motors are properly secured to the cassette, each transmission mechanism may be activated to move the guide wire and/or working catheter a predetermined distance or rotation and then measure the distance actually moved or rotated by use of sensors. If the movement conforms to the predetermined parameters the system is shown to be working and operational. When the detected movement of the guide wire and/or working catheter does not conform to set parameters the system will show an error message.

Cassette24is designed with ergonomic considerations in mind, handle64enables easy manipulation and movement of the cassette and cassette base by an operator to position the system relative to the patient. Cover44may include a latch210located on the inside surface of the cover or in within the housing of the cassette to hold guide wire50during exchanges or when manipulating more than one wire. Catheter system10may include system for inflating working catheter54, and a system for injecting a contrast media. Specifically, work station14may include a control mechanism for remotely controlling a pump for the injection of a contrast media.

Referring toFIG. 9cassette24is shown without cover44and without housing42. Cassette24includes a base plate70that supports first axial drive mechanism48and first rotational drive mechanism56. Axial drive mechanism48and rotational drive mechanism56are positioned and secured consecutively/in series along a longitudinal axis of base plate70. First axial drive mechanism48is shown positioned closer to the back end of cassette24, behind first rotational drive mechanism56. It should be noted, however, that first rotational drive mechanism56may be positioned behind first axial drive mechanism48. It is believed that positioning rotational drive mechanism56closer to the patient provides for increased control of rotation of the guide wire, since any pressure and/or friction from the rollers in axial drive mechanism48is located distal the patient.

Referring toFIGS. 9 and 10, first axial drive mechanism48includes a first roller72and a second roller74working in cooperation to drive guide wire50in an axial direction. First roller72is spring biased toward second roller74with sufficient force to provide movement to guide wire50upon rotation of rollers72,74. It may be possible to adjust the spring force to ensure proper operation of the system. The spring force is set to allow rotation of guide wire50about its axis. In one embodiment first roller72has a first engagement surface and second roller74includes a second engagement surface. Guide wire50is removably placed between the first and second engagement surfaces of the first and second rollers72and74respectively. A solenoid may be used to move first roller and second roller closer toward and away from one another to capture and release guide wire between first and second rollers72,74. A solenoid may be used to move a holder supporting one of the rollers toward the other roller. A spring on the holder may be employed to bias one roller toward the other roller to provide a sufficient force on the guide wire50to effectively permit translation of the guide wire along its longitudinal axis upon rotation of at least one of the rollers.

Second roller74is driven by a drive gear or roller76via a belt78. Sufficient tension is applied to belt78via a tension member80. However, second roller74may be driven directly from one of the capstans40in motor drive base22.

In alternative embodiments, pair of rollers72,74may comprise a roller and an anvil or a roller and any grip surface wherein the pressure between that grip surface and a roller is sufficient to drive guide wire50along its longitudinal axis.

Further referring toFIGS. 6,9and11, first rotational drive mechanism56includes a first rotational drive mechanism supporting block92, a second rotational drive mechanism supporting block94, and a rotational drive mechanism96. Rotational drive mechanism96includes a plate100, four pairs of rollers102,104,106,108, four pairs of roller fasteners110,112,114,116, supported on four pairs of roller axles118,120,122,124, a rotational drive mechanism comb, a longitudinal axis128, and a pair of cylindrical protrusions130that extend through and are supported in a bore in each of supporting blocks92and94. Pair of cylindrical protrusions130,132are substantially concentric with rotational drive mechanism96, extending outward from either end of rotational drive mechanism96along its longitudinal axis128. First rotational drive mechanism supporting block92and second rotational drive mechanism supporting block94are transverse to longitudinal axis128of base plate70and are spaced out along the longitudinal axis of base plate70a distance sufficient to accommodate rotational drive mechanism96between them. Rotational drive mechanism96is suspended and secured between first rotational drive mechanism supporting block92and second rotational drive mechanism supporting block94over base plate70by pair of cylindrical protrusions130,132, which also serve as a path for guide wire50to extend. Referring toFIG. 14the elements of rotational drive mechanism96may be supported on a rotating assembly206that rotates between supporting blocks92and94.

Each supporting block92,94includes a guide wire slit84extending substantially radially outward from the longitudinal axis128of rotational drive mechanism96. Each of the four pairs of rollers102,104,106,108meets along a longitudinal axis of rotational drive mechanism96. Four pairs of rollers102,104,106,108and four pairs of roller fasteners110,112,114,116are positioned over four pairs of axles118,120,122,124with four pairs of roller fasteners110,112,114,116fixing four pairs of rollers102,104,106,108along four pairs of axles118,120,122,124. While rotational drive mechanism is described with four pair of rollers, it may be possible to use a single pair of rollers, two or three pair of rollers or more than four pair of rollers. Referring toFIG. 14an element208is illustrated that represents the path that guide wire50would extend through when the rotating assembly is in the load and unload position. When the rotating assembly is in the load and unload position the path represented by element208is in alignment with guide wire slits84in supporting blocks92and94that are illustrated inFIG. 9.

When cover44of cassette24is in the closed position, a rotational drive mechanism locator may be used to assist in the positioning of guide wire50downward toward the longitudinal axis of rotational drive mechanism96to help locate and maintain guide wire50between the four pairs of rollers102,104,106,108. Guide wire50is releasably engaged between four pairs of rollers102,104,106,108in first rotational drive mechanism56. When robotic vascular catheter system10is used during a procedure, the rollers within the engagement surfaces of the four pairs of rollers102,104,106,108move toward one another to apply sufficient pressure to rotate guide wire50upon rotation of rotational drive mechanism96while still permitting guide wire50to be independently moved along its longitudinal axis by axial drive mechanism48. The rotation of guide wire50results from the torque imparted on guide wire50because of the frictional forces between four pairs of rollers102,104,106, and108during rotation of rotational drive mechanism96. The rollers in the pairs of rollers102-108are free to rotate about their vertical axis allowing a guide wire50to move axially. The pressure between each pair of rollers is sufficient to impart a rotation to a guide wire50located therebetween when the entire rotational drive mechanism is rotated. The rollers may be moved away from one another to permit easy insertion and removal of guide wire50to load and unload the guide wire within the rotational drive mechanism. One set of the rollers may be moved away from the other set of rollers when cover44is in the open position and allowed to move back toward the other set of rollers when cover44is in a closed position. In order to easily remove or insert guide wire50into rotational drive mechanism96between the rollers a vertical path98must align with guide wire slit84. When cover44is opened, the rotational drive mechanism rotates to a load/unload position in which vertical path98is aligned with guide wire slit84thereby allowing easy insertion and/or removal of guide wire50from the rotational drive mechanism. In an alternative embodiment, the rollers do not move away from one another but allow for manual insertion and removal of guide wire50between the rollers. The manual insertion may be permitted by the flexibility of the rollers themselves or by permitting one of the spring biased rollers to move away from the second in the pair of rollers to allow insertion of guide wire50.

Alternative embodiments of four pairs of rollers102,104,106,108include, but are not limited to, more or less than four pairs of rollers. Also, four pairs of rollers102,104,106,108comprise pairs of rollers and anvils, each roller paired up with an anvil and creating sufficient pressure to rotate guide wire50upon rotation of rotational drive mechanism96while still permitting guide wire50to be independently moved along its longitudinal axis. Similarly, four pairs of rollers102,104,106,108may alternatively comprise a plurality of rollers and any grip surface where the pressure between each roller and that grip surface is sufficient to rotate guide wire50upon rotation of rotational drive mechanism96while still permitting guide wire50to be independently moved along its longitudinal axis. In another embodiment rotational drive mechanism may include two engagement surfaces that may or may not rotate in the axial direction of the longitudinal axis of the guide wire.

When cover44of cassette24is in open cover position, first axial drive mechanism48and first rotational drive mechanism56are positioned such to facilitate loading guide wire50and working catheter54. In the insertion and removal position, guide wire slits84in supporting blocks92,94and guide wire path98of rotational drive mechanism96are substantially aligned. Similarly, pair of rollers72,74of first axial drive mechanism48and four pairs of rollers102,104,106,108of first rotational drive mechanism56are substantially aligned. This enables guide wire50to extend through both first axial drive mechanism48and first rotational drive mechanism56. As discussed above, each of the pair of rollers in the axial drive mechanism and rotational drive mechanism may move apart to facilitate easy insertion and removal of guide wire50when cover44is in the open position.

Further referring toFIG. 6second axial drive mechanism52comprises a pair of rollers136, and a working catheter channel138. Pair of rollers136releasably engage working catheter54in working catheter channel138. When cassette24is in open cover position, second axial drive mechanism52is positioned such to facilitate loading working catheter54between pair of rollers136. When cover44of cassette24is closed, working catheter54is loaded and releasably engaged between pair of rollers136. Alternate embodiments of second axial drive mechanism52include, but are not limited to, an embodiment wherein pair of rollers136comprises a roller and an anvil or a roller and any grip surface wherein the pressure between that grip surface and a roller is sufficient to drive working catheter54along its longitudinal axis. Other axial drive mechanisms are also contemplated and may be used.

Referring toFIG. 1workstation14comprises a user interface142. User interface142enables a user to enter commands controlling the axial motion of guide wire50via first axial drive mechanism48, the axial motion of working catheter54via second axial drive mechanism52, and the rotational motion of guide wire50via first rotational drive mechanism56. In an alternative embodiment of robotic vascular catheter system10, the user would additionally be capable of controlling a guide catheter144from workstation14, in an axial and/or rotational manner.

In a preferred embodiment, user interface142includes a first screen146and a second screen148. First screen146and second screen148are configured to present information and images potentially useful to a user of robotic vascular catheter system10. User interface142further includes a touch screen150, having a pair of joysticks152having variable speed control, a first jog button154for 1 mm jogs, and a second jog button156for 5 mm jogs. First jog button154and second jog button156have continuous jog capability. Depression of the jog buttons will move the guide wire50a set distance forward. Jog buttons may be used for movement of guide wire50and/or working catheter54. Rotational Jog button may be set to rotate a pre-set degree or it may be set to rotate a selected degree. Another button may be used to accelerate the speed of the guide wire50or provide a multiplier so that the variable speed control reacts in a heightened manner. For example if movement of a joystick a set distance results in the movement of the guide wire at a set speed in normal operation, the guide wire would move at a multiple of the set speed by depressing the button to accelerate the speed.

In alternative embodiments, user interface142may have various configurations. For instance, touch screen150may be integrated with x-ray or other imaging data. In fact, a variety of data and controls may be integrated on a single screen, including, but not limited to, contrast media insertion control, balloon inflation control, image processing control(s), hemodynamic data, etc. Alternative joystick configurations include, but are not limited to separate joysticks may be provided for each drive mechanism, rather than two joysticks for controlling all drive mechanisms.

Robotic vascular catheter system10may further incorporate a number of safety features and conveniences (not shown). For instance, robotic vascular catheter system10may be capable of providing a mechanism for a user to manually override it during a procedure. In the event, that the operator must manually align the rotational drive mechanism to remove the guide wire50, it is contemplated that the rotational drive mechanism can be moved to a load unload position so that the engagement surfaces in the rotational drive mechanism are separated and in line with the slits in rotational drive mechanism supports. Additionally, workstation14may incorporate a system allowing a user to voice-activate controls, a feature which could be overridden by an emergency stop. There may also be a force limitation mechanism. Robotic vascular catheter system10could have a pre-determined limit to the amount of force that could be placed on guide wire50. If the motors were to apply a force greater than the pre-determined amount, a clutch act to disengage the wheels from the motors. For example if any of the drive mechanisms were to become stuck and unable to rotate a clutch mechanism would act to allow the motors to rotate without causing damage to the stuck drive mechanism or the motor itself.

Another possible feature is a slippage-detecting mechanism. Such a mechanism would provide a continuous check between the desired and actual movements of guide wire50or working catheter54and rollers, pair of rollers72,74of first axial drive mechanism48and four pairs of rollers102,104,106,108of first rotational drive mechanism56. This mechanism could provide warnings when a given threshold has been crossed. This threshold may remain constant throughout a procedure or may vary depending on the location of system components in the heart. In one embodiment, an ancillary encoder (not shown) may be used to give the exact location of guide wire50, in terms of both axial and rotational movement, and working catheter54, in terms of axial movement, during a procedure. Pair of rollers72,74and four pairs of rollers102,104,106,108would be positioned near a plurality of idler rollers158that check the movement of the robotic vascular catheter system10, comparing the movement of the rollers to motor movement. Note that these features and conveniences are exemplary and should not be read to be exhaustive.

Referring toFIGS. 3,7,8and13in a preferred embodiment cassette24further includes a coupling mechanism162for securing a y-connector160attached to a guide catheter144and a guide catheter support arm, shown as a rod164. Coupling mechanism162releasably secures y-connector160. Y-connector160connects to guide catheter144. Y-connector160further provides a means for administering drugs to a patient during the PCI procedure. In one embodiment, robotic vascular catheter system10provides a user the ability to remotely control drug administration through y-connector160. Guide catheter144may be able to pivot about its longitudinal axis independent of y-connector160. The y-connector includes three legs. A first leg is attached to the guide catheter144. A second leg is angled away from the longitudinal axis of the guide catheter to permit introduction of a contrast agent or medicine. A one way valve prohibits bodily fluid from exiting the second leg. A third leg extends away from the guide catheter and allows insertion of a working catheter and guide wire through the y-connector. The third leg also includes a one way valve that permits insertion and removal of the working catheter and guide wire but prohibits bodily fluids from exiting the third leg.

A rod164is coupled to cassette24at a point along the front end of cassette24and supports guide catheter support26at its other end. Rod164is adjustable, and capable of translating away from cassette24and back towards cassette24and moving independently of cassette24, to help position guide catheter24using methods known in the art. In alternative embodiments, rod164may take on any number of configurations capable of supporting guide catheter support26and guide catheter144. For example, guide rod164may include telescoping segments.

Guide catheter support26, shown as a spring-loaded clamp, provides support for guide catheter144. Guide catheter support26is at a point between the front end of cassette24and patient30during a procedure. In this position, guide catheter support26helps prevent unwanted movement of the guide catheter144and its contents, affording greater accuracy when performing a procedure.

Referring toFIG. 6, when guide wire50and working catheter54have been loaded in robotic vascular catheter system10, cover44of cassette24is closed guide wire50extends out of the back end of cassette24through an opening in housing42. Moving toward the front end of cassette24, guide wire50passes through first axial drive mechanism48, through first rotational drive mechanism56, and then converges with working catheter54at a convergence zone166. Working catheter54enters cassette24through a slot168in the side of housing42. Before converging with guide wire50at convergence zone166, working catheter54first passes through second axial drive mechanism52. Working catheter54includes a hollow over the wire portion, which guide wire50passes into at convergence zone166. Working catheter54with guide wire50in its over the wire portion exits the front end of cassette24through an opening172. Cassette24may include a channel configured to constrain the working catheter along a predefined path from a first point where the longitudinal axis of the working catheter and the longitudinal axis of the guide wire are not coaxial to a point where the longitudinal axis of the working catheter and the longitudinal axis of the guiding catheter are co-axial. The path is located within the housing and may include a groove or other physical means to form at least a portion of the path.

Further referring toFIG. 6, y-connector160is connected to a proximal end of guide catheter144. Guide catheter144has a central bore. Guide wire50and working catheter54pass through y-connector160into central bore174of guide catheter144upon exiting cassette24through opening172. In a preferred embodiment, guide catheter144runs substantially parallel to rod164from y-connector160to guide catheter support26, where it is releasably secured. Guide catheter support26facilitates movement of guide wire50and working catheter54within central bore174of guide catheter144, by helping to keep guide catheter144straight.

Y-connector160is releasably secured to cassette24by coupling mechanism162, shown in a preferred embodiment as a spring-biased clamp inFIGS. 7 and 8. Coupling mechanism162includes a frame176, a handle178, and at least one spring180. Frame176includes a receiving portion182against which y-connector160is secured. Handle178includes a lever arm184and a capture portion186. Capture portion186applies sufficient pressure to secure y-connector160against receiving portion182of frame176when lever arm184is not depressed. Handle178pivots about a pivot point188. Springs180exert an upward force on lever arm184at a distance from pivot point188, biasing capture portion186of handle178toward receiving portion182of frame176. Referring toFIG. 8, when lever arm184is depressed, springs180are also compressed. Capture portion186of handle178pivots about pivot point188, moving away from y-connector160and receiving portion182and releasing y-connector160. Referring back toFIG. 7, when handle178is released lever arm184is again forced upward, pivoting about pivot point188. Capture portion186moves in toward receiving portion182and y-connector160, releasably securing y-connector160.

The exemplary procedure begins after a diagnostic procedure has been completed, leaving a diagnostic guide wire (not shown) in a heart190(shown inFIG. 4), heart190including an aorta192and an aortic arch194. Before using robotic vascular catheter system10, guide catheter144is run up into aorta192over the diagnostic guide wire, the diagnostic guide wire is removed, and guide catheter144is positioned into either a right ostium196opening to the right coronary artery or a left ostium198opening to the circumflex or left anterior descending arteries, depending where a lesion200is located. The shape of guide catheter144varies based on which ostium it is to enter. As discussed above, bedside system12is likely already fixed to patient's bed28.

For the purposes of clarity, steps for advancing guide catheter50and working catheter54and loading bedside system12will be discussed separately and in turn. One of skill in the art would recognize that a number of the steps in the discussion are interchangeable without deviating significantly from the method.

Guide catheter144is attached to y-connector160. A y-connector introducer (not shown) is placed into y-connector160. Guide wire50is advanced through the y-connector introducer into guide catheter144and then removed. Working catheter54is loaded onto guide wire50. Working catheter54is then manually advanced up into guide catheter144over guide wire50until it is near the free end of guide wire50.

Cassette24is coupled to motor drive base22over the sterile, plastic cover. Articulating arm18is locked relative to patient30and cover44of cassette24is opened, activating engagement-disengagement mechanism, which causes the drive mechanisms to position for loading guide wire50and working catheter54. Guide wire50is positioned into guide wire path98between four pairs of rollers102,104,106,108of first rotational drive mechanism56, and into guide wire slit84and pair of rollers72,74of first axial drive mechanism48. The back end of guide wire50extends outwardly through the back of housing42and may contain a guide wire holder or support to contain the length of guide wire not being used within the patient. Working catheter54is placed in working catheter channel138between pair of rollers136of second axial drive mechanism52. After positioning guide wire50and working catheter54, cover44of cassette24is closed, again activating the engagement-disengagement mechanism. Robotic vascular catheter system10is loaded, drive mechanisms having releasably engaged guide wire50and working catheter54.

Y-connector160is releasably secured to cassette24by depressing handle178, placing y-connector160between frame176and handle178. In this manner guide catheter144is releasably secured to the cassette24.

The user operates the controls at workstation14. In the above-discussed preferred embodiment of workstation14, touch screen150, a pair of joysticks152, a first jog button154, and a second jog button156are operated to direct the motion of guide wire50and working catheter54. As shown inFIG. 5, guide wire50is typically moved and then followed by working catheter54until guide wire50is moved across lesion200. Once guide wire50has crossed lesion200, working catheter54is driven across, often fine tuning the position using first jog button154, second jog button156, or a combination of both.

Referring toFIG. 12, an alternative axial drive212member may be used. For example pinch rollers may be replaced with a two belt mechanism.

Referring toFIG. 13, cassette24includes a guide catheter support202. Y-connector coupling mechanism is supported by guide catheter support202. In an alternative embodiment, guide catheter support202may include a sled204that can be moved in a fore aft direction so that the guide catheter may be moved in a direction along its longitudinal axis. Cassette24may also include a drive mechanism to rotate sled204such that the guide catheter is rotated about its longitudinal axis, and a drive mechanism to move sled204in the fore aft direction such that the guide catheter may be moved along the longitudinal axis of the guide wire. The drive mechanisms used to move sled204may be located in the motor drive base22and move the sled204relative to cassette24, so that sled204may be moved independently of the guide wire and/or working catheter.

Referring now toFIGS. 15 through 28C, another exemplary embodiment of a cassette for use with a robotic catheter system is shown. Similar to the embodiment discussed above, cassette300may be equipped with a guide wire301and a working catheter303to allow a user to perform a catheterization procedure utilizing cassette300. In this embodiment, bedside system12includes a cassette300configured to be mounted to a motor drive base302.FIG. 15shows a bottom perspective view of cassette300prior to mounting to motor drive base302. Motor drive base302includes a first capstan304, a second capstan306, and a third capstan308, and cassette300includes a first capstan socket310, a second capstan socket312, and a third capstan socket314. Cassette300includes a housing316, and housing316includes a base plate318.

Each of the capstan sockets is configured to receive one of the capstans of motor drive base302. In the embodiment shown, base plate318includes a hole or aperture aligned with each of the capstan sockets310,312, and314to allow each capstan to engage with the appropriate capstan socket. The engagement between the capstans and capstan sockets allows the transfer of energy (e.g., rotational movement) generated by one or more actuators (e.g., motors) located within motor drive base302to each of the drive mechanisms (discussed below) within cassette300. In one embodiment, a single actuator provides energy to each of the drive mechanisms. In another embodiment, there is an actuator that drives capstan304, an actuator that drives capstan306, and an actuator that drives capstan308. Further, the positioning of the capstans and capstan sockets helps the user to align cassette300relative to motor drive base302by allowing cassette300to be mounted to motor drive base302only when all three capstan sockets are aligned with the proper capstan.

In one embodiment, the motors that drive capstans304,306, and308are located within motor drive base302. In another embodiment, the motors that drive capstans304,306, and308may be located outside of base302connected to cassette300via an appropriate transmission device (e.g., shaft, cable, etc.). In yet another embodiment, cassette300includes motors located within the housing of cassette300. In another embodiment, cassette300does not include capstan sockets310,312, and314, but includes an alternative mechanism for transferring energy (e.g., rotational motion) from an actuator external to the cassette to each of the cassette drive mechanisms. For example, rotational movement may be transferred to the drive mechanisms of cassette300via alternating or rotating magnets or magnetic fields located within motor drive base302.

In the embodiment shown, cassette300also includes a guide catheter support311that supports guide catheter317at a position spaced from cassette300. As shown, guide catheter support311is attached to cassette300by a rod313. Rod313and guide catheter support311are strong enough to support guide catheter317without buckling. Guide catheter support311supports guide catheter317at a position spaced from the cassette, between the patient and the cassette to prevent buckling, bending, etc. of the portion of guide catheter317between the cassette and the patient.

Referring toFIG. 16, cassette300is shown mounted to motor drive base302. As shown inFIG. 16, cassette300includes an outer cassette cover320that may be attached to housing316. When attached to housing316, outer cassette cover320is positioned over and covers each of the drive mechanisms of cassette300. By covering the drive assemblies of cassette300, outer cassette cover320acts to prevent accidental contact with the drive mechanisms of cassette300while in use.

Referring toFIG. 17, cassette300is shown in the “loading” configuration with outer cassette cover320removed. Cassette300includes a y-connector support assembly322, an axial drive assembly324, and a rotational drive assembly326. Generally, the various portions of cassette300are placed in the loading configuration to allow the user to load or install a guide wire and/or working catheter into cassette300. Further, in the exemplary embodiment shown, y-connector support assembly322is located in front of axial drive assembly324, and axial drive assembly324is located in front of rotational drive assembly326within cassette300.

Y-connector support assembly322includes a chassis328and a y-connector restraint330. Base plate318includes a support arm332that supports y-connector support assembly322. Chassis328is coupled to the front of support arm332via pin connection334.

A central groove or depression336extends the length of chassis328. Y-connector338rests within central groove336of chassis328. Y-connector338includes a first leg340, a second leg342, and a third leg344. First leg340is configured to attach to a guide catheter such that the central lumen of the y-connector is in fluid communication with the central lumen of the guide catheter. Second leg342is angled away from the longitudinal axis of y-connector338. Second leg342of y-connector338allows introduction of a contrast agent or medicine into the lumen of the guide catheter. A one way valve prohibits bodily fluid from exiting second leg342. Third leg344extends away from the guide catheter toward axial drive assembly324. In use, guide wire301and working catheter303are inserted into third leg344of y-connector338via opening346and may be advanced through y-connector338into the lumen of the guide catheter. The third leg also includes a one way valve that permits insertion and removal of the working catheter and guide wire but prohibits bodily fluids from exiting third leg344.

Chassis328is rotatable about an axis defined by pin connection334to allow chassis328to be placed in the “loading position” shown inFIG. 17. In the loading position, chassis328is positioned at about a 45 degree angle, shown by angle line315, relative to support arm332. Chassis328is moved to the “loading position” to provide easier access to opening346of the third leg344allowing the user to feed guide wire301and working catheter303into y-connector338.

Cassette300also includes an axial drive assembly324. Axial drive assembly324includes a first axial drive mechanism, shown as guide wire axial drive mechanism350, and a second axial drive mechanism, shown as working catheter axial drive mechanism352. Axial drive assembly324also includes a top deck354, a cover356, and a latch or handle358.

Generally, guide wire axial drive mechanism350is configured to releasably engage and drive (e.g., to impart motion to) guide wire301along its longitudinal axis. In this manner, guide wire axial drive mechanism350provides for advancement and/or retraction of guide wire301. Working catheter axial drive mechanism352is configured to releasably engage and drive (e.g., to impart motion to) working catheter303along its longitudinal axis. In this manner, working catheter axial drive mechanism352provides for advancement and/or retraction of working catheter303.

Top deck354is mounted to a central portion360of base plate318. Top deck354includes a guide wire channel364and a working catheter channel366. Guide wire channel364is positioned generally perpendicular to the top surface of top deck354and runs the length of top deck354in the longitudinal direction. Working catheter channel366is positioned generally perpendicular to the top surface of top deck354and is located at an angle relative to guide wire channel364. A plurality of tabs368extend vertically from the top surface of top deck354along guide wire channel364.

InFIG. 17, cover356is shown in the open position. Handle358is moved to a position generally parallel to the longitudinal axis of cassette300to allow cover356to move to the open position. Cover356is mounted to top deck354via hinges370. Cassette300includes a restraint structure that acts to restrain movement of the guide wire when cover356is in the closed position. As shown, the restraint structure includes a plurality of tabs372extending from the lower surface of cover356. Tabs372are positioned such that when cover356is closed, tabs372are positioned within a portion of guide wire channel364between tabs368such that tabs372restrain movement of guide wire301in a vertical direction (i.e., restrains movement of the guide wire in a direction perpendicular to the top surface of top deck354).

When cover356is in the open position, both guide wire axial drive mechanism350and working catheter axial drive mechanism352are exposed allowing the user to load cassette300with a guide wire and working catheter. With cover356open, guide wire301is loaded into axial drive assembly324by placing the guide wire into guide wire channel364. Tabs368facilitate the placement of guide wire301by aiding the user in aligning the guide wire with guide wire channel364. In addition, working catheter303is loaded into axial drive assembly324by placing the working catheter into working catheter channel366. As will be described in more detail below, once the guide wire and working catheter are positioned within guide wire channel364and working catheter channel366, respectively, engagement surfaces of guide wire axial drive mechanism350and working catheter axial drive mechanism352are brought into engagement with the guide wire and working catheter respectively.

Both top deck354and central portion360of base plate318are shaped to define a recess374. Working catheter channel366includes an opening376located within recess374. Recess374allows opening376to be closer to y-connector338and also closer to the entry incision allowing working catheter303to be advanced farther into the patient's vascular system than if opening376were located further away from y-connector338or the entry incision. As can be seen inFIG. 16, working catheter303includes a hub305at its proximal end that is too large to fit through opening376. Thus, the closer that opening376is to y-connector338and to the entry incision the further working catheter303can be advanced into the patient's vascular system.

Cassette300also includes a rotational drive assembly326. Rotational drive assembly326includes a rotational drive mechanism, shown as guide wire rotational drive mechanism380, a cover384, and a journal388. Guide wire rotational drive mechanism380includes a chassis382and an engagement structure386. Rotational drive assembly326is configured to cause guide wire301to rotate about its longitudinal axis. Engagement structure386is configured to releasably engage guide wire301and to apply sufficient force to guide wire301such that guide wire301is allowed to rotate about its longitudinal axis while permitting guide wire301to be moved axially by guide wire axial drive mechanism350.

In the embodiment shown, rotational drive assembly326is supported within housing316such that rotation drive assembly326is permitted to rotate within housing316. Engagement structure386applies sufficient force to guide wire301that the rotation of rotation drive assembly326causes guide wire301to rotate about its longitudinal axis as rotational drive assembly326rotates.

Chassis382includes a guide wire channel390. Guide wire channel390is positioned generally perpendicular to the top surface of chassis382and runs the length of chassis382in the longitudinal direction. A plurality of tabs392extend vertically from the top surface of chassis382along guide wire channel390. InFIG. 17, cover384is shown in the open position. Cover384is mounted to chassis382via hinge394. Cassette300includes a restraint structure that acts to restrain movement of the guide wire when cover384is in the closed position. As shown, the restraint structure includes a plurality of tabs396extending from the lower surface of cover384. The top surface of chassis382includes a plurality of recesses398configured to receive tabs396when cover384is in the closed position. Tabs396are positioned such that when cover384is closed, tabs396are positioned over guide wire channel390such that tabs396prevent guide wire301from falling out of guide wire channel390(i.e., restrains movement of the guide wire in a direction perpendicular to the top surface of chassis382). In addition, the sidewalls of guide wire channel390and the engagement surfaces of wheels522and524prevent or restrain movement of guide wire301in other directions perpendicular to the longitudinal axis of guide wire301. Thus, tabs392and guide wire channel390hold guide wire301within channel390during rotation of rotational drive assembly326.

When cover384is in the open position, guide wire channel390is exposed allowing the user to load cassette300with a guide wire. With cover384open, guide wire301is loaded into rotational drive assembly326by placing the guide wire into guide wire channel390. Tabs392facilitate the placement of guide wire301by aiding the user in aligning the guide wire with guide wire channel390. As will be described in more detail below, once guide wire301is positioned within guide wire channel390engagement surfaces of engagement structure386are brought into engagement with the guide wire. In one embodiment, when the user activates controls (e.g., controls located at workstation14) to open cover384, rotational drive assembly326is automatically rotated such that guide wire channel390is facing generally upward to allow for easy loading or removal of guide wire301.

In one embodiment, cassette300is a modular cassette that allows various components of cassette300to be removed and/or switched out with other components. In an exemplary embodiment, a user may wish to control the guide wire using bedside system12and to control the working catheter manually. In this embodiment, a user may mount only guide wire axial drive mechanism350and rotational drive assembly326within housing316of cassette300. In another exemplary embodiment, a user may wish to control the working catheter using bedside system12and to control the guide wire manually. In this embodiment, a user may mount only working catheter drive mechanism352within housing316of cassette300. In another embodiment, cassette300may include additional locations for mounting drive mechanisms for any type of additional catheter devices that may be used during a procedure. For example, a user may be able to couple drive mechanisms to cassette300to control the movement and/or control of an intravascular ultrasound catheter.

Referring toFIG. 18, cassette300is shown in the “loaded” or “use” position. In the “loaded” position, y-connector support assembly322is rotated downward such that y-connector338is aligned with guide wire channel364of axial drive assembly324. The axial alignment allows guide wire301and working catheter303to be moved into and/or out of y-connector338via operation of guide wire axial drive mechanism350and working catheter axial drive mechanism352. Cover356is shown in the closed position overlying both the guide wire axial drive mechanism350and the working catheter axial drive mechanism352. As shown, cover356also covers guide wire channel364and working catheter channel366. As such, cover356acts to prevent interference with the various components of axial drive assembly324during use.

After cover356is moved to the closed position, handle358is rotated approximately 90 degrees such that a portion of handle358is positioned over cover356. As will be discussed in greater detail below, rotation of handle358to the closed position shown inFIG. 18causes the engagement surface of the guide wire axial drive mechanism350and of the working catheter axial drive mechanism352to move together engaging the guide wire and working catheter, respectively.

In addition, when cassette300is moved to the “loaded” position, cover384is moved to the closed position overlying rotational drive mechanism380and guide wire channel390as shown inFIG. 18. Like cover356, cover384acts to prevent interference with the various components of rotational drive assembly326during use. In one embodiment, a user may activate controls (e.g., controls located at workstation14) to cause the various components of cassette300to move between the “loading” and “loaded” positions. In addition, cassette300may also be configured to allow the user to move the various components of cassette300between the “loading” and “loaded” positions manually.

Referring toFIG. 18, in the “loaded” or “use” configuration, the longitudinal axis (and the internal lumen) of y-connector338is aligned with guide wire channel364of axial drive assembly and with guide wire channel390of rotational drive assembly326. This alignment provides a path extending from the rear of cassette300through y-connector338into the guide catheter through which the guide wire is advanced or retracted during axial movement of the guide wire. In various embodiments, components of cassette300, including top deck354, chassis382, cover356, and cover384, may be made from a transparent or translucent plastic.

Referring toFIG. 19, an exploded perspective view from above of axial drive assembly324is shown.FIG. 19generally depicts the components of axial drive assembly324. Guide wire axial drive mechanism350and working catheter axial drive mechanism352are positioned above base plate318and top deck354is fastened to central portion360of base plate318above guide wire axial drive mechanism350and working catheter axial drive mechanism352. Thus, guide wire axial drive mechanism350and working catheter axial drive mechanism352are generally enclosed within a chamber defined by top deck354and central portion360of base plate318when axial drive assembly324is assembled. Top deck354includes a plurality of apertures362to receive various portions of both axial drive mechanism350and working catheter axial drive mechanism352.

Axial drive mechanism350includes a drive element400, a first roller assembly402, a second roller assembly404, and a guide wire axial motion sensor assembly, shown as encoder assembly406. First roller assembly402and second roller assembly404are both mounted within a housing416. Drive element400includes a drive shaft408, a drive wheel410, a bearing412, and a screw414. Drive shaft408is configured to engage second capstan306of motor drive base302such that drive shaft408and drive wheel410rotate in response to rotation of second capstan306. First roller assembly402includes an idler wheel or roller418, a wheel housing420, a bearing422, and a spring424.

Drive wheel410includes an outer or engagement surface426, and roller418includes an outer or engagement surface428. Generally, when guide wire axial drive mechanism350is placed in the “use” or “engaged” position (shown inFIG. 22), guide wire301is positioned between drive wheel410and roller418such that engagement surface426of drive wheel410and engagement surface428of roller418are able to engage the guide wire. In this embodiment, engagement surface426and engagement surface428define a pair of engagement surfaces. The force applied to guide wire301by engagement surface426and engagement surface428is such that drive wheel410is able to impart axial motion to guide wire301in response to the rotation of drive shaft408caused by rotation of second capstan306. This axial motion allows a user to advance and/or retract a guide wire via manipulation of controls located at workstation14. Roller418is rotatably mounted within wheel housing420and rotates freely as drive wheel410rotates to drive guide wire301. Spring424is biased to exert a force onto wheel housing420causing roller418to engage the guide wire against drive wheel410. Spring424is selected, tuned, and/or adjusted such that the proper amount of force is applied to guide wire301by engagement surface426and engagement surface428in the “engaged” position. In other embodiments, additional drive elements may be added as necessary to impart axial motion to the guide wire.

Second roller assembly404includes an idler wheel or roller430, a wheel housing432, a bearing434, and a spring436. Encoder assembly406includes shaft438, magnetic coupling440, idler wheel or roller442, bearing444, and a screw446. Roller430includes an outer or engagement surface448and roller442includes an outer or engagement surface450.

In the “engaged” position, guide wire301is positioned between roller430and roller442such that engagement surface448of roller430and engagement surface450of roller442are able to engage the guide wire. In this embodiment, engagement surface448and engagement surface450define a pair of engagement surfaces. The force applied to guide wire301by engagement surface448and engagement surface450is such that drive wheel410is able to pull guide wire301past roller430and442. In this way, the pair of non-active or idle rollers430and442help support guide wire301and maintain alignment of guide wire301along the longitudinal axis of cassette300.

Roller430is rotatably mounted within wheel housing432, and roller442is rotatably mounted to shaft438. Both rollers430and442are mounted to rotate freely as drive wheel410imparts axial motion to guide wire301. Spring436is biased to exert a force onto wheel housing432causing roller430to engage guide wire301against roller442. Spring436is selected, tuned, and/or adjusted such that the proper amount of force is applied to guide wire301by engagement surface448and engagement surface450in the “engaged” position to support the guide wire while still allowing the guide wire to be moved axially by drive wheel410. In other embodiments, additional pairs of non-active or idler rollers may be added as needed to provide proper support and alignment for the guide wire. In one embodiment, spring424and spring436are selected or adjusted such that the force applied to guide wire301by wheels430and442is approximately the same as the force applied to guide wire301by wheels410and418.

Encoder assembly406includes magnetic coupling440that engages a magnetic encoder located within motor drive base302. The magnetic encoder is configured to measure an aspect (e.g., speed, position, acceleration, etc.) of axial movement of the guide wire. As roller442rotates, shaft438rotates causing magnetic coupling440to rotate. The rotation of magnetic coupling440causes rotation of the magnetic encoder within motor drive base302. Because rotation of roller442is related to the axial movement of guide wire301, the magnetic encoder within motor drive base302is able to provide a measurement of the amount of axial movement experienced by guide wire301during a procedure. This information may be used for a variety of purposes. For example, this information may be displayed to a user at workstation14, may be used in a calculation of or estimated position of the guide wire within the vascular system of a patient, may trigger an alert or alarm indicating a problem with guide wire advancement, etc.

As shown inFIG. 19, first roller assembly402and second roller assembly404are both mounted within a housing416. Housing416provides a common support for first roller assembly402and second roller assembly404. As will be discussed in more detail below, first roller assembly402and second roller assembly404are moved away from drive wheel410and roller442, respectively, when axial drive assembly324is placed in the “loading” configuration. This facilitates placement of guide wire301between the opposing pairs of engagement surfaces of guide wire axial drive mechanism350. Housing416allows first roller assembly402and second roller assembly404to be moved together (e.g., in sync) away from drive wheel410and roller442, respectively, when axial drive assembly324is placed in the “load” configuration.

Axial drive assembly324also includes working catheter axial drive mechanism352. Working catheter axial drive mechanism352includes a drive element452and a working catheter axial motion sensor assembly, shown as working catheter encoder assembly454. Drive element452includes a drive shaft456, a drive wheel458, a bearing460, and a screw462. Drive shaft456is configured to engage first capstan304of motor drive base302such that drive shaft456and drive wheel458rotate in response to rotation of first capstan304. Encoder assembly454includes shaft464, a roller466, an encoder linkage468, a spring470, and a magnetic coupling480.

Drive wheel458includes an outer or engagement surface472and roller466includes an outer or engagement surface474. When working catheter axial drive mechanism352is in the “engaged” position, a working catheter is positioned between drive wheel458and roller466, such that engagement surface472and engagement surface474are able to engage working catheter303. In this embodiment, engagement surfaces472and474define a pair of engagement surfaces. The force applied to working catheter303by engagement surfaces472and474is such that drive wheel458is able to impart axial motion to the working catheter in response to the rotation of drive shaft456caused by rotation of first capstan304. This axial motion allows a user to advance and/or retract a working catheter via manipulation of controls located at workstation14. Roller466is rotatably mounted to shaft464and rotates freely as drive wheel458rotates to drive the working catheter.

Spring470is coupled to a first end of linkage468. The second end of linkage468includes an aperture476that is pivotally coupled to a post478extending from the inner surface of top deck354. Spring470is biased to exert a force on to linkage468causing linkage468to pivot about post478to force roller466to engage working catheter303against drive wheel458. Spring470is selected, tuned, and/or adjusted such that the proper amount of force is applied to working catheter303by engagement surfaces472and474in the “engaged” position to allow drive wheel458to impart axial movement to the working catheter.

Encoder assembly454includes magnetic coupling480that engages a magnetic encoder located within motor drive base302. The magnetic encoder is configured to measure an aspect (e.g., speed, position, acceleration, etc.) of axial movement of the working catheter. As roller466rotates, shaft464rotates causing magnetic coupling480to rotate. The rotation of magnetic coupling480causes rotation of the magnetic encoder within motor drive base302. Because rotation of roller466is related to the axial movement of working catheter303, the magnetic encoder within motor drive base302is able to provide a measurement of the amount of axial movement experienced by the working catheter during a procedure. This information may be used for a variety of purposes. For example, this information may be displayed to a user at workstation14, may be used in a calculation of or estimated position of the working catheter within the vascular system of a patient, may trigger an alert or alarm indicating a problem with working catheter advancement, etc.

As will be discussed in more detail below, roller466is moved away from drive wheel458when axial drive assembly324is placed in the “loading” configuration. This facilitates placement of the working catheter between the opposing pairs of engagement surfaces of working catheter axial drive mechanism352.

In one embodiment, cassette300and/or motor drive base302includes a locking mechanism that is configured to lock the position of guide wire301during manipulation of the working catheter303and to lock the position of working catheter303during manipulation of guide wire301. In one embodiment, the locking mechanism acts to increase the force applied to the guide wire by the engagement surfaces when the working catheter is being advanced and to increase the force applied to the working catheter by the engagement surfaces when the guide wire is being advanced.

Referring toFIGS. 19 and 20, top deck354includes a plurality of cylindrical sleeves, first sleeve482, second sleeve484, and third sleeve486, extending from the inner or lower surface of top deck354. Top deck354also includes a plurality of cylindrical collars, first collar488, second collar490, and third collar492, extending from the upper surface of top deck354. Collar488is in axial alignment with sleeve482. Collar490is in axial alignment with sleeve484. Collar492is in axial alignment with sleeve486. Each of the collars488,490, and492define an aperture362. In the embodiment shown, sleeve482and collar488are configured to receive working catheter drive element452, sleeve484and collar490are configured to receive guide wire drive element400, and sleeve486and collar492are configured to receive guide wire encoder assembly406. Apertures362provide access to screws414,446, and462once top deck354is mounted over axial drive assembly324.

Top deck354includes a collar494aligned with and located at the back end of guide wire channel364. Collar494is configured to receive front shaft512that extends from chassis382of rotational drive assembly326. Collar494is configured to allow front shaft512(and consequently the rest of rotational drive assembly326) to rotate about the longitudinal axis of guide wire channel390relative to axial drive assembly324. In one embodiment, rotational drive assembly326is able to rotate relative to housing316of cassette300while axial drive assembly324does not rotate relative to housing316. In another embodiment, both rotational drive assembly326and axial drive assembly324rotate relative to housing316of cassette300.

FIG. 20is a bottom perspective view of cassette300showing top deck354mounted above guide wire axial drive mechanism350and working catheter axial drive mechanism352.FIG. 20shows working catheter drive element452, guide wire drive element400, and guide wire encoder assembly406received within sleeves482,484, and486. A support structure496extends from the lower surface of top deck354. Spring470is coupled at one end to support structure496allowing spring470to compress and expanded between linkage468and support structure496.

As shown, the lower end of drive shaft408includes a keyed recess498, and the lower end of drive shaft456includes a keyed recess500. Keyed recess500is one embodiment of first capstan socket310, and keyed recess498is one embodiment of second capstan socket312. Keyed recess500is configured to receive a capstan, such as first capstan304, and keyed recess498is configured to receive a capstan, such as second capstan306. First capstan304and second capstan306are keyed to fit within keyed recess500and498and to engage and turn drive shafts456and408upon rotation of the capstans.

As shown, magnetic coupling440of guide wire encoder assembly406includes a circular array of magnets504. Magnetic coupling480of working catheter encoder assembly454includes a circular array of magnets506. Magnetic couplings440and480engage with magnetic encoders positioned within motor drive base302. The magnetic encoders of motor drive base302are coupled to appropriate electronics to detect and measure rotation of rollers442and466and to calculate axial motion of guide wire301and working catheter303based on the measured rotations. While this embodiment discloses the use of magnetic encoders to detect the axial motion of the guide wire and working catheter, other sensors may be used. In one embodiment, axial motion of the guide wire may be detected by an optical sensor that detects movement of the guide wire and/or working catheter by scanning the surface of the guide wire and/or working catheter as it passes the optical sensor. In one such embodiment, the optical sensor includes an LED light source and a detector (e.g., a complimentary metal oxide semiconductor, other light detecting circuitry, etc.) that detects light reflected off the surface of the guide wire and/or working catheter, and the light detected by the detector is analyzed (e.g., by a digital signal processor) to determine movement of the guide wire and/or working catheter. In another embodiment, the surface of the guide wire and/or working catheter may include indicia that are detected to determine axial movement of the guide wire. In other embodiments, other types of sensors (e.g., resolvers, sychros, potentiometers, etc.), may be used to detect movement of the guide wire and/or working catheter.

Cassette300also includes a series of magnets508positioned below guide wire channel364. Because, in at least some embodiments, the guide wire is made from a magnetic material, magnets508are able to interact with the guide wire. In this embodiment, the magnetic attraction created by magnets508helps the user position guide wire301during loading by drawing guide wire301into guide wire channel364. The magnetic attraction created by magnets508also tends to hold guide wire301within guide wire channel364during advancement and/or retraction of the guide wire. Further, magnets508help to hold guide wire301straight (i.e., parallel to the longitudinal axis of guide wire channel364) to aid in the axial movement caused by guide wire axial drive mechanism350.

FIG. 21shows a top view of axial drive assembly324in the “loading” configuration with handle358(shown in broken lines) rotated such that it is generally parallel to guide wire channel364.FIG. 22shows a top view of axial drive assembly324in the “loaded” or “use” configuration with handle358rotated such that it is generally perpendicular to guide wire channel364. Generally, when handle358is moved from the position ofFIG. 22to the position ofFIG. 21, the engagement surfaces of both guide wire axial drive mechanism350and working catheter axial drive mechanism352are moved away from each other increasing the space between the pairs of wheels in the drive mechanisms. This provides sufficient space between the wheels of each drive mechanism to allow the user to place guide wire301and working catheter303into the channels between the wheels. Generally, as handle358is moved from the position ofFIG. 21to the position ofFIG. 22, the engagement surfaces of both guide wire axial drive mechanism350and working catheter axial drive mechanism352are moved toward each other bringing the engagement surfaces of each drive mechanism into engagement with guide wire301or working catheter, respectively.

In the embodiment shown, handle358is coupled to a shaft357. Shaft357includes a cam section359and housing416includes a cam surface417. As handle358rotates from the position shown inFIG. 21to the position shown inFIG. 22, cam section359of shaft357moves along cam surface417causing housing416to move toward guide wire301. This motion engages guide wire301between drive wheel410and roller418and between roller430and roller442. When handle358is brought into the position ofFIG. 22, springs424and436are compressed to the proper tension to allow drive wheel410to move guide wire301axial along its longitudinal axis.

In addition, housing416includes a tab419that is coupled to linkage468. Thus, linkage468rotates about post478when housing416is moved to the position shown inFIG. 21. This movement draws roller466away from working catheter drive wheel458. When, housing416is moved to the position shown inFIG. 22, roller466is moved toward catheter drive wheel458such that the engagement surfaces of roller466and drive wheel458engage working catheter303. In one embodiment, cassette300is configured to allow the user to move the axial drive assembly324between the “use” and “loading” positions via manipulation of controls at workstation14. Cassette300may also be configured to allow the user to move the axial drive assembly324between the “use” and “loading” position manually.

FIGS. 23A and 23Bshow a perspective view of rotational drive assembly326showing cover384in the open position. Rotational drive assembly326includes rotational drive mechanism380, chassis382, an engagement structure386, and a disengagement assembly510. Chassis382fits over engagement structure386and provides mounting for various components of rotational drive assembly326. Chassis382includes a front shaft512and a rear shaft514. As discussed above, front shaft512is rotatably received within collar494of top deck354, and rear shaft514is rotatably received within collar516such that rotational drive mechanism380is able to rotate relative to journal388. As shown, collar516extends through and is supported by journal388such that rear shaft514rotates within collar516as rotational drive mechanism380is rotated. Collar516rests within a recess or slot formed within journal388. In another embodiment, rear shaft514may be in direct contact with journal388such that rear shaft514rotates within the recess or slot of journal388as rotational drive mechanism380is rotated. Guide wire channel390extends the length of chassis382through both front shaft512and rear shaft514.

Rotational drive mechanism380includes rotation bevel gear518that engages a drive gear520. Bevel gear518is rigidly coupled to front shaft512of chassis382such that rotation of bevel gear518rotates chassis382. Drive gear520is coupled to a rotational actuator positioned in motor drive base302and engages bevel gear518. Rotation of the rotational actuator in motor drive base302causes drive gear520to rotate which causes bevel gear518to rotate which in turn causes rotational drive mechanism380to rotate. Rotational drive mechanism380is allowed to rotate about the longitudinal axis of guide wire channel390via the rotatable connections between front shaft512and top deck354and between rear shaft514and journal388. Bevel gear518further includes a slot519in axial alignment with guide wire channel390. Slot519allows the user to place guide wire301into guide wire channel390by dropping it in vertically as opposed to threading it through bevel gear518. In one embodiment, rotational drive assembly326is equipped with one or more sensors that are configured to measure an aspect (e.g., speed, position, acceleration, etc.) of rotation of the guide wire and/or any other structure of rotational drive assembly326. The sensors that measure rotation of the guide wire may include magnetic encoders and/or optical sensors as discussed above regarding the sensors that measure axial motion of the guide wire and/or working catheter. However, any suitable sensor (e.g., resolvers, sychros, potentiometers, etc.) may be used to detect rotation of the guide wire.

Referring toFIG. 23B, engagement structure386is shown according to an exemplary embodiment. As shown, engagement structure386includes four pairs of idler wheels or rollers. Each pair of rollers includes a fixed wheel522and an engagement wheel524. Fixed wheels522are rotatably coupled to chassis382via fixation posts530. Each engagement wheel524is part of an engagement wheel assembly523. Each engagement wheel assembly523includes a pivot yoke532and a spring536. Each engagement wheel is mounted to pivot yoke532via a mounting post538. Each pivot yoke532is pivotally coupled to chassis382via fixation posts534.

Each fixed wheel522includes an outer or engagement surface526and each engagement wheel524includes an outer or engagement surface528. Generally,FIG. 23Bshows engagement structure386in the “use” or “engaged” position. In the “engaged” position, guide wire301is positioned between fixed wheels522and engagement wheels524such that engagement surfaces526and528are able to engage guide wire301. In this embodiment, engagement surface526and engagement surface528of each pair of rollers define a pair of engagement surfaces. The force applied to guide wire301by engagement surfaces526and528is sufficient to cause the guide wire to rotate about its longitudinal axis as rotational drive assembly326is rotated. Further, the force applied to guide wire301by engagement surfaces526and528is also sufficient to allow the guide wire to be moved axially by guide wire axial drive mechanism350.

Springs536are biased to exert a force onto pivot yokes532causing each engagement wheel524to engage the opposite fixed wheel522. The generally L-shape of pivot yoke532allows springs536to be aligned with the longitudinal axis of guide wire301and still cause engagement between engagement wheels524, fixed wheels522, and the guide wire. This allows the lateral dimension of rotational drive assembly326to be less than if springs536were positioned perpendicular to the longitudinal axis of the guide wire. Springs536are selected, tuned, and/or adjusted such that the proper amount of force is applied to the guide wire by engagement surfaces526and528in the “engaged” position.

Cassette300also includes a series of magnets540located beneath guide wire channel390. Because, in at least some embodiments the guide wire is made from a magnetic material, magnets540are able to interact with the guide wire. In this embodiment, the magnetic attraction created by magnets540helps the user position guide wire301during loading by drawing guide wire301into guide wire channel390. The magnetic attraction created by magnets540also tends to hold guide wire301within guide wire channel390during advancement and/or retraction of the guide wire. Further, magnets540help to hold guide wire301straight (i.e., parallel to the longitudinal axis of guide wire channel390) to aid in the axial movement caused by guide wire axial drive mechanism350.

Rotational drive assembly also includes a disengagement assembly510. Disengagement assembly510includes a stepped collar542, a base plate544, and a spring546. Stepped collar542is coupled to base plate544, and spring546is coupled at one end to chassis382and at the other end to base plate544. Stepped collar542includes a slot548in axial alignment with guide wire channel390. Like slot519, slot548allows the user to place guide wire301into guide wire channel390by dropping it in vertically as opposed to threading it through stepped collar542. Base plate544includes a plurality of engagement arms550that extend generally perpendicular to the plane defined by base plate544.

Generally, disengagement assembly510allows engagement wheels524to be moved away from fixed wheels522. Referring toFIGS. 24 and 25,FIG. 25shows a top view of rotational drive assembly326in the “loading” configuration, andFIG. 24shows a top view of rotational drive assembly326in the “loaded” or “use” configuration. To cause engagement wheels524to disengage from guide wire301, an axially directed force (depicted by the arrow inFIG. 25) is applied to stepped collar542. This causes base plate544to move toward the front of cassette300in the direction of the arrow. As base plate544moves forward, spring546is compressed, and engagement arms550are brought into contact with pivot yokes532. The contact between engagement arms550and pivot yokes532causes springs536to be compressed, and pivot yokes532pivot about fixation posts534. As pivot yokes532pivot, engagement wheels524are drawn away from fixed wheels522. As shown inFIG. 25, this provides sufficient space between engagement wheels524and fixed wheels522to allow the user to place guide wire301into guide wire channel390.

When the axial force is removed from stepped collar542, engagement wheels524move from the position shown inFIG. 25to the “engaged” position shown inFIG. 24. When the axial force is removed, spring546and springs536are allowed to expand causing engagement arms550to disengage from pivot yokes532. Pivot yokes532pivot counter-clockwise about fixation posts534, bringing engagement wheels524back toward guide wire channel390causing engagement surfaces526of fixed wheels522and engagement surfaces528of engagement wheels524to engage guide wire301.

In one embodiment, a user may activate controls located at workstation14to cause rotational drive assembly326to move between the “use” position and the “loading” position. In this embodiment, rotational drive assembly326is automatically rotated such that guide wire channel390is facing generally upward to allow for easy loading or removal of the guide wire. In the embodiment shown, chassis382rotates relative to stepped collar542. In this embodiment, when rotational drive assembly326is in the “loading” position, a path defined by the engagement surfaces of engagement structure386and guide wire channel390align with slot548of stepped collar542. Motor drive base302may also include a structure (e.g., two rods, etc.) that applies the axial force to stepped collar542in response to a user's activation of controls located at workstation14. The structure applies the axial force to the stepped collar542to cause engagement structure386to disengage from the guide wire. Next, cover384is moved from the closed position to the open position allowing the user to access guide wire channel390to either remove or install the guide wire. In one embodiment, cassette300and/or motor drive base302includes motors or other actuators that cause the covers of cassette300to open in response to a user's activation of controls at workstation14.

FIG. 26shows a cross-sectional view of rotational drive assembly326as indicated by the corresponding sectional line inFIG. 18.FIG. 26depicts guide wire301within guide wire channel390. As shown, inFIG. 26when cover384is in the closed position, tab396rests over guide wire channel390. As shown inFIG. 26, tab396helps hold guide wire301in guide wire channel390by restricting movement of guide wire301in a direction perpendicular to the plane defined by base plate544(this direction of restriction is the vertical direction in the orientation ofFIG. 26). Guide wire301is engaged on one side by engagement surface526of fixed wheel522and on the other side by engagement surface528of engagement wheel524.

FIG. 27shows a cross-sectional view of axial drive assembly324as indicated by the corresponding sectional line inFIG. 18.FIG. 27depicts guide wire301within channel364. Guide wire301is engaged on one side by engagement surface426of drive wheel410and on the other side by engagement surface428of roller418.

Under certain circumstances, it may be desirable to disconnect rotational drive assembly326from cassette300. Referring toFIGS. 28A-28C, cassette300may be configured to allow rotational drive assembly326(shown schematically by broken lines inFIGS. 28A-28C) to be disconnected from cassette300. In one such embodiment, cassette300includes journal388, and rotational drive mechanism380is rotatably coupled to journal388. In this embodiment, journal388is releasably coupled to housing316such that both journal388and rotational drive mechanism380may be removed from housing316without removing the guide wire from the patient and/or without removing cassette300from base302. In one such embodiment, following release of journal388from housing316, the user may remove (e.g., pull, slide, etc.) both journal388and rotational drive mechanism380over the proximal end of the guide wire.

In one embodiment, journal388includes a slot552, and base plate318includes a release button554. Release button554is coupled to ramp556, and ramp556includes wedge-shaped end558. As shown inFIG. 28A, wedge-shaped end558passes through slot552to couple journal388to base plate318. When a downward force is applied to release button554, wedge-shaped end558is allowed to disengage from slot552allowing rotational drive assembly326and journal388to disconnect from base plate318.

Next, rotational drive assembly326is disengaged from guide wire301. As discussed above, regardingFIGS. 24 and 25, by applying an axial force to stepped collar542, engagement structure386disengages from the guide wire. Once engagement structure386is disengaged from guide wire301, the rotational drive assembly326may be moved over the proximal end of the guide wire while the guide wire slides freely though guide wire channel390. Removal of rotational drive assembly326from cassette300may be necessary if, for example, bedside system12loses power preventing motor drive base302from placing rotational drive assembly into the “loading” configuration. In this case, removal of rotational drive assembly326allows the user to either remove the guide wire and working catheter from the patient manually or to complete the procedure manually.

In one embodiment, cassette300is a single-use or disposable cassette that includes a use restriction element that acts to functionally disable the cassette from being used for more than one catheterization procedure. In one embodiment, the use restriction element is a frangible piece located within one or more of the capstan sockets that prevents cassette300from being remounted onto the capstans of motor drive base302after it has been removed. In another embodiment, the use restriction element is an RFID tag that communicates with an RFID receiver indicating whether cassette300has previously been used. In another embodiment, the use restriction element includes a bar code associated with cassette300that must be scanned prior to use. If the bar code scanned is associated with a cassette that has already been used, reuse of the cassette is prevented.

Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. Any of the features, elements, or components of any of the exemplary embodiments discussed above may be used alone or in combination with any of the features, elements, or components of any of the other embodiments discussed above. It is to be understood that the forms of the invention shown and described herein are to be taken as presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art having the benefit of this description of the invention. Changes may be made in the elements described herein without departing form the spirit and scope of the invention as described in the following claims.