Deflectable sheath handle assembly and method therefor

A deflectable catheter assembly includes a deflectable body manipulatable by a rotating actuator of a housing assembly. The housing assembly includes a sliding member having a threaded portion including a first threaded portion having a first pitch and a second threaded portion having a second pitch, where the first pitch is different than the second pitch.

TECHNICAL FIELD

Deflectable sheath assemblies having deflectable distal ends, and more particularly, a handle assembly for a deflectable sheath assembly.

TECHNICAL BACKGROUND

Medical devices and/or procedures are used in many different branch vessels and require a wide variety in placement techniques. One example of a placement technique is through use of a deflectable sheath. Typically, a deflectable sheath is controlled at a proximal end of the catheter by a control handle that operates a pull wire to deflect the sheath. However, with conventional catheter steering mechanisms, it can be difficult to accurately position the catheters in certain body vessels, such as branch veins. For instance, the mechanisms are awkward or require the use of two hands. Other steering mechanisms require pull wires to be wound and unwound around a rotatable cam wheel, causing increased fatigue on the pull wires, and potentially shortening the life of the device. Furthermore, some deflectable catheters involve relatively large catheter sheaths. The larger sheaths can be difficult to manipulate within a patient, and have increased deflection forces, frustrating efforts of a physician attempting to control deflection angle during a procedure.

SUMMARY OF THE INVENTION

The present invention relates to a deflectable sheath assembly comprising: a deflectable body extending from a distal portion to a proximal portion; a rotatable actuator disposed at the proximal portion of the deflectable body, the rotatable actuator being threadingly engaged with a sliding member such that rotation of the actuator causes longitudinal movement of the sliding member; the sliding member fixedly coupled with a pull wire extending along the deflectable body to the deflectable body distal portion such that pull wire longitudinal movement causes deflection of the deflectable body distal portion; and wherein the rotatable actuator is threadingly engaged with the sliding member through a first threaded portion having a first pitch in co-axial alignment with a second threaded portion having a second pitch that is different than the first pitch, wherein the first and second threaded portions are either part of the rotatable actuator or the sliding member, but not both and wherein the sliding member operablely engages the rotatable actuator with the first threaded portion at a first longitudinal position and with the second threaded portion at a second longitudinal position such that rotation of the actuator causes different rates of translational movement of the sliding member per actuator rotation and consequently different rates of translational movement of the pull wire and further consequently different rates of deflection of the deflectable distal body portion when the sliding member engages the first threaded portion compared to the second threaded portion.

The present invention also relates to a deflectable sheath assembly comprising: a deflectable body extending from a distal portion to a proximal portion, the deflectable body having a passage therethrough; a rotatable actuator disposed at the proximal portion of the deflectable body, the rotatable actuator being threadingly engaged with a sliding member by an intermediate cam such that rotation of the rotatable actuator causes longitudinal translation of the sliding member; wherein the sliding member is fixedly coupled with a pull wire extending along the deflectable body to the deflectable body distal portion; and wherein the cam disposed between the rotatable actuator and the sliding member includes a first threaded cam portion having a first pitch in co-axial alignment with a second threaded cam portion having a second pitch that is different than the first pitch for varying a rate of translation of the sliding member and deflection of the deflectable body distal portion relative to rotation of the rotatable actuator.

The present invention further relates to a method for deflecting the distal portion of a deflectable body of a deflectable sheath assembly, comprising the steps of: providing an actuator of the deflectable sheath assembly, the actuator being threadingly engaged with a sliding member and including a first threaded actuator portion having a first pitch in co-axial alignment with a second threaded actuator portion having a second pitch that is different than the first pitch, the sliding member fixedly coupled with a pull wire that is operably coupled to a distal portion of the deflectable body of the deflectable sheath assembly; rotating the actuator to cause the first threaded portion to engage the sliding member to longitudinally translate the sliding member at a first translational rate per actuator rotation, thereby deflecting the distal portion of the deflectable body at the first rate; and further rotating the actuator to cause the second threaded actuator portion to engage the sliding member to further longitudinally translate the sliding member at a second translational rate per actuator rotation different than the first rate, thereby further deflecting the distal portion of the deflectable body at the second rate different than the first rate.

Still further, the present invention also relates to a deflectable sheath assembly, which comprises: a deflectable body extending from a distal portion to a proximal portion; a rotatable actuator disposed at the proximal portion of the deflectable body and including a pin threadingly engaged with a sliding member, wherein the sliding member comprises a first threaded sliding member portion having a first pitch in co-axial alignment with a second threaded sliding member portion having a second pitch that is different than the first pitch, the sliding member fixedly coupled with a pull wire that is operably coupled to a distal portion of the deflectable body of the deflectable sheath assembly; wherein the pin of the rotatable actuator engages the first threaded sliding member portion to longitudinally translate the sliding member at a first translational rate per actuator rotation, thereby deflecting the distal portion of the deflectable body at the first rate; wherein the pin of the rotatable actuator further engages the second threaded sliding member portion to further longitudinally translate the sliding member at a second translational rate per actuator rotation different than the first rate; and wherein longitudinal translation of the sliding member causes the coupled pull wire to deflect the distal portion of the deflectable body at at least one of the first rate or the second rate different than the first rate.

Moreover, the present invention also relates to a deflectable sheath assembly, which comprises: a deflectable body extending from a distal portion to a proximal portion; a rotatable actuator disposed at the proximal portion of the deflectable body and threadingly engaged with a pin of a sliding member, the rotatable actuator including a first threaded actuator portion having a first pitch in co-axial alignment with a second threaded actuator portion having a second pitch that is different than the first pitch, the sliding member fixedly coupled with a pull wire that is operably coupled to a distal portion of the deflectable body of the deflectable sheath assembly; wherein the pin of the sliding member threadingly engages the first threaded actuator portion to longitudinally translate the sliding member at a first translational rate per actuator rotation, thereby deflecting the distal portion of the deflectable body at the first rate; and wherein the pin of the sliding member further threadingly engages the second threaded actuator portion to further longitudinally translate the sliding member at a second translational rate per actuator rotation different than the first rate; and wherein longitudinal translation of the sliding member causes the coupled pull wire to deflect the distal portion of the deflectable body at at least one of the first rate or the second rate different than the first rate.

Still further, the present invention describes a method for deflecting the distal portion of a deflectable body of a deflectable sheath assembly, comprising the steps of: providing an actuator of the deflectable sheath assembly including a pin threadingly engaged with a sliding member comprising a first threaded sliding member portion having a first pitch in co-axial alignment with a second threaded sliding member portion having a second pitch that is different than the first pitch, wherein the sliding member is fixedly coupled with a pull wire that is operably coupled to a distal portion of the deflectable body of the deflectable sheath assembly; rotating the actuator to cause the pin to engage the first sliding member portion to longitudinally translate the sliding member at a first translational rate per actuator rotation, thereby deflecting the distal portion of the deflectable body at the first rate; and further rotating the actuator to cause the pin to engage the second sliding member portion to further longitudinally translate the sliding member at a second translational rate per actuator rotation different than the first rate, thereby further deflecting the distal portion of the deflectable body at the second rate different than the first rate.

Yet further, the present invention relates to a method for deflecting the distal portion of a deflectable body of a deflectable sheath assembly, comprising the steps of: providing an actuator of the deflectable sheath assembly threadingly engaged with a pin of a sliding member, the actuator including a first threaded actuator portion having a first pitch in co-axial alignment with a second threaded actuator portion having a second pitch that is different than the first pitch, the sliding member being fixedly coupled with a pull wire that is operably coupled to a distal portion of the deflectable body of the deflectable sheath assembly; rotating the actuator to cause the first threaded actuator portion to threadingly engage the pin of the sliding member to longitudinally translate the sliding member at a first translational rate per actuator rotation, thereby deflecting the distal portion of the deflectable body at the first rate; and further rotating the actuator to cause the second threaded actuator portion to threadingly engage the pin of the sliding member to further longitudinally translate the sliding member at a second translational rate per actuator rotation different than the first rate, thereby further deflecting the distal portion of the deflectable body at the second rate different than the first rate.

What is needed is a deflectable catheter that overcomes the shortcomings of previous deflectable catheters. What is further needed is a deflectable catheter that allows for more ease positioning of the distal end of the deflectable catheter, for example for a catheter having a relatively larger sized sheath, and that is usable with a single hand.

DESCRIPTION OF THE EMBODIMENTS

A deflectable sheath assembly100is illustrated inFIGS. 1 and 2, and generally includes a deflectable body120, a handle assembly140, and a pullwire130. The deflectable body120extends from a distal end portion122to a proximal end portion124, and includes a passage123therethrough. The passage123allows for instruments to be introduced through the sheath assembly100and into the patient. Near the distal end portion122is a deflectable distal tip126that is, in an option, more flexible than the remainder of the deflectable body120.

Near the deflectable distal tip126, a distal portion of the pullwire130(FIG. 2) is coupled with the deflectable body120. For example, the pullwire130(FIG. 2), in an option, is fixed to the deflectable body120at a distal end of the distal tip126. In another option, the pullwire130is fixed to the deflectable body120with a pullwire anchor.

The pullwire130is disposed through a lumen of the deflectable body120, and translates longitudinally through the lumen. A proximal portion of the pullwire130is coupled with a portion of the handle assembly140. As the pullwire130is moved longitudinally through the lumen of the deflectable body120, the pullwire130, which is fixed to the distal portion of the deflectable body120, deflects the distal end portion122of the deflectable body120.

The proximal end portion124of the deflectable body120is fixed to the handle assembly140and assists a user in manipulation of the distal end portion deflectable body120. The handle assembly140allows for the user to displace the pullwire130relative to the deflectable body120with an actuator, for example, by a rotating knob142.

Disposed near the proximal end portion124of the deflectable body120is a flexible strain relief195, as illustrated inFIGS. 1 and 2. The strain relief195is available in different sizes to accommodate different sheath diameters, for example deflectable bodies120. The strain relief195is made from a flexible material to allow it to flex with the deflectable body120. The integrated strain relief195assists in preventing the deflectable body120from kinking near the handle assembly140by maintaining a minimum bend radius. The stiffness of the strain relief195decreases over the length of the strain relief195, with the proximal end being stiffer than the distal end. The change in stiffness provides a smooth transition from the rigid handle assembly140to the flexible deflectable body120.

The handle assembly140, shown in greater detail inFIGS. 2 and 9, includes a housing144that houses several components therein. The housing144includes handle body145and a rear cap147, where the knob142separates the handle body145from the rear cap147. Within the housing144is a sliding member146that interacts with the rotating knob142, and the sliding member146moves longitudinally within the handle assembly140. In an option, the sliding member146includes a threaded portion148that is threadingly engaged with internal threads143of the rotating knob142, or a cam184coupled with the rotating knob142.

As illustrated inFIG. 9, the threaded portion182, in an option, includes a first threaded portion151and a second threaded portion153, where the second threaded portion153is more distal than the first threaded portion151. The first threaded portion151has a different pitch than the second threaded portion. In an option, the first threaded portion151has a finer pitch than the second threaded portion153. In a further option, the threaded portion182includes a third threaded portion157having a different pitch than at least one of the first or second threaded portions. In an example, the first threaded portion151differs from the second threaded portion153by about 16%. For instance, an example includes the first threaded portion151having a pitch of 0.250 in/rev, and the second threaded portion153having a pitch of 0.300 in/rev. In another example, the first threaded portion151has a pitch of 0.200 in/rev, and the second threaded portion153having a pitch of 0.250 in/rev. In a further example, a third threaded portion has a pitch that is about 16% different than the second threaded portion, and the second threaded portion has a pitch that is about 16% different than the first threaded portion. In an example, the first threaded portion has a pitch of about 0.200 in/rev, the second threaded portion has a pitch of about 0.250 in/rev, and the third threaded portion has a pitch of about 0.300 in/rev.

It should be noted that a gradual change in pitch is possible, or several discrete different threaded portions are possible. This allows for greater control of the deflection of the distal end of the catheter assembly when the deflectable body becomes more deflected. The pitch of the threaded portion is varied along the sliding member146such that the rate of translation of the sliding member146varies relative to rotation of the actuator. In a further option, the pitch of the threaded portion includes square threads. The sliding member146further includes features that mate with a support, further discussed below.

Further options for the sliding member146include, but are not limited to, embodiments shown inFIGS. 7-10. InFIGS. 7,8, and9, the sliding member146includes a projection, such as a pin180. The pin180is engaged with an internal threaded portion182of a cam184. The cam184is fixed to the rotating knob142. In an option, the threaded portion182has a constant thread. In another option, the threaded portion182includes a varying pitch. As the knob is rotated, the threads of the cam184engage with the pin180, and translate the sliding member146longitudinally to deflect the distal end portion of the deflectable body120. Referring toFIG. 10, the internal threaded portion182and pin180can be reversed as shown in such that the cam184has an internal pin185and the sliding member146has an external thread187. It should be noted that the external thread187can have a variable pitch, and other threaded portions can be varied to achieve the affect of having a variable pitch.

Further included within the handle assembly140are a first bearing155and an optional second bearing150. In an option, the first bearing155has a larger inner diameter than the second bearing150. In an option, the first and second bearings155,150are coupled with the handle body145and are disposed around the sliding member146. The first bearing155allows for rotation of the knob142while controlling the position of the knob142both radial and axially. The second bearing150allows for the sliding member146to slide axially while controlling its position radially.

The handle assembly140further includes a plurality of telescoping tubes160, such as hypotubes, as illustrated inFIGS. 2 and 3. The telescoping tubes160provide support to the pullwire130such that it can be loaded in tension and compression without buckling. In an option, the telescoping tubes include a first outer tube162, such as a curved, outer hypotube. The tubes160also include a second inner tube164, such as a relatively smaller, substantially straight inner hypotube. The first outer tube162is fixedly coupled with another component. For example, the first outer tube162is embedded in the wall of the deflectable body120near the proximal end portion124, for instance at the location where the pullwire130exits the wall of the body120. The lumen inside the body120wall containing the pullwire130extends into the outer tube162.

Referring toFIGS. 2 and 3, the lumen terminates inside the outer tube162at a distal end163of the outer tube162. The inner tube164fits into a proximal end165of the outer tube162. The inner tube164is axially movably relative to the outer tube162, for example the inner tube164telescopes within the outer tube162. The pullwire130is disposed through the lumen in the wall of the deflectable body120, into the outer tube162, through the outer tube162and into the inner tube164. The pullwire130terminates at the proximal end of the inner tube164. The pullwire130is fixed to the inner tube164but is allowed to slide freely inside the outer tube162. The inner tube164is fixed to the sliding member146.

Referring toFIGS. 4A and 4B, handle body145has one or more supports170therein. For example, the one or more supports170can be integrated with the handle body145or the deflectable body120, and provide reinforcement to the deflectable body120. In another example, the one or more supports170are independent components fixed between the deflectable body120and the handle body145. The one or more supports170position the deflectable body120within the handle body145, and in an option have features that mate with features inside the handle body145. In one example, the one or more supports170include a generally annular shape171that mates with pockets172of the handle body145. These features hold the one or more supports170, and the deflectable body120, in a fixed position within the handle body145.

The one or more supports170further include features that mate with the sliding member146, and prevent the sliding member146from rotating as it slides when the actuator is rotated. The features provide a guide for the sliding member146to travel as it slides. For example, the one or more supports170includes one or more channels176that engage a projection149from the sliding member146, and the projection149of the sliding member146travels along the guide channels176. The projection149and/or channels176can have a variety of cross-sectional shapes. In another option, the projection149can be disposed along the one or more supports170, and the channels176can be disposed along the sliding member146.

In another option, the one or more supports170further include features that mate with the end cap of the housing assembly. For example, the one or more supports170provide a backbone through the center of the handle assembly, and a proximal end of the one or more supports170is fixed to the rear cap147of the handle assembly140. This allows for the entire rotating knob to be exposed around its perimeter, allowing a user to access the knob in any orientation.

Referring again toFIG. 1, the handle assembly140, in an example, the end cap, includes either a hemostasis valve193with flushport assembly196or luer fitting at the proximal end of the handle assembly. The hemostasis valve is sealingly engaged with the passage123and allows devices of various sizes to be passed into and through the deflectable sheath assembly while protecting against blood loss and air embolism. The flushport assembly196allows the sheath assembly100to be flushed to remove air. The flushport assembly196also allows various fluids to be injected through the sheath assembly100during a medical procedure. The luer fitting allows a variety of external components with a mating luer fitting to be attached to the proximal end of the sheath assembly100. The luer fitting allows other devices to be passed into and through the passage of the deflectable sheath.

During use of the deflectable sheath assembly100, the distal end portion of the deflectable body120is introduced into a patient. The assembly100is navigated through the patient, for example, by deflecting the distal end portion of the deflectable body120. To deflect the distal end portion of the deflectable120, the actuator is rotated. As the actuator is rotated, the threads of the actuator or the cam engage the threads or a projection of the sliding member146. The actuator is fixed longitudinally, causing the sliding member146to translate longitudinally as the threads enmesh with each other. The sliding member146, in an option, slides along a guide of a support. For instance, a projection of the sliding member slides along a recess or channel within a support member.

As the sliding member translates longitudinally, in an option, the rate of longitudinal movement of the slider is varied relative to rotation of the actuator. For example, the sliding member includes two or more threaded portions have at least a first pitch and a second pitch, and the actuator is rotated along the first pitch and the second pitch, and the first pitch is different than the second pitch. In another example, varying the rate of longitudinal movement of the sliding member146includes decreasing the longitudinal movement of the slider relative the rotation of the actuator.

The sliding member146is fixed to an inner tube164and moves axially when the knob is rotated. The inner tube164is fixed to the pullwire, causing the pullwire to translate longitudinally along the deflectable body120. The inner tube164telescopes within the outer tube162during the longitudinal movement.

In an example, when the knob is rotated clockwise (as viewed from the proximal end of the handle) by the user, the sliding member146moves proximally and the inner tube164slides proximally but stays inside the outer tube. The pullwire is fixed to the inner tube164, the proximal movement loads the pullwire in tension and also the pullwire longitudinally moves toward a proximal end of the deflectable sheath assembly. The proximal movement of the pullwire causes the distal tip of the sheath to deflect. Conversely, when the knob is rotated counterclockwise, the sliding member146moves distally and the inner tube164slides distally. This places the pullwire in compression, and the pullwire longitudinally moves toward a distal end of the deflectable sheath assembly. The movement toward the distal end causes the distal tip to straighten.

Advantageously, the sheath assembly allows for improved mechanical advantage in deflecting sheaths having relatively greater deflection forces, such as larger diameter sheaths, sheaths having greater wall thicknesses, or sheaths having reinforcement materials therein. For example, the variable pitch threaded assists in increasing the amount of mechanical advantage as deflection angle and force increase. This assists in maintaining a constant user input throughout the deflection angle. The sheath assembly further assists the user in manipulating the sheath assembly allowing for single-handed operation.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Although the use of the implantable device has been described for use as a lead in, for example, a cardiac stimulation system, the implantable device could as well be applied to other types of body stimulating systems. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.