Patent Description:
Modern medical techniques generally need to balance the comfort of the patient with the time taken to perform procedures, the expense of those procedures and the associated risks. If an error is made during a procedure, it is desirable to rectify the error with as little deviation from the correct procedure as possible, and without increasing risk - e.g. without having to perform multiple penetrations of the subject's skin.

Antegrade peripheral revascularization, for example, can require guidewire access to the superficial femoral artery via needle-puncture into the common femoral artery (CFA). The CFA is often the site of choice as the femoral head is beneath and it facilitates effective post-procedure compression for haemostasis and prevention of external bleeding, retroperitoneal haemorrhage and pseudo-aneurysm formation.

The initial needle puncture is usually done blind by palpation alone, under fluoroscopy or else with the aid of ultrasound visualization. This is followed by insertion of the guidewire which is also typically blind, followed by insertion of an access sheath over the guidewire by the Seldinger technique.

The deep formal artery - profunda femoris artery (PFA) - can be accidentally cannulated instead of the superficial femoral artery (SFA). This may be due to procedural or anatomical factors.

Procedurally, guidewire-insertion is done blind as it requires a bimanual approach and many operators do not ultrasound or perform fluoroscopy during this step. This means the guidewire will take whichever initial trajectory it has upon exiting the needle. Moreover, interaction with pre-existing stenotic disease may skew the direction of the guidewire.

Anatomically, the real-estate for puncture of the CFA can be very short (about <NUM> - <NUM>) and the PFA (deep femoral artery) ostium tends to be situated on the lower surface of the artery resulting in preferential passage of the needle-directed guidewire into it (see <FIG>). This can be problematic since SFA access must be achieved before revascularization can take place. Salvage of the guidewire and correction of its trajectory into the SFA extends the time taken for the operative duration, and increases the volume of radiation exposure and contrast used. Moreover, repeated rewiring may also injure or dissect the PFA.

Not infrequently, access is lost and a second puncture needs to be made. Repuncture carries the additional risks of bleeding, hematoma and pseudo-aneurysm formation.

Techniques to prevent PFA cannulation centre around puncturing more proximally on the CFA with the intention to "bounce" the wire off the back-wall into the SFA. Such techniques can often be ineffective. Moreover, the vasculature includes high bifurcations, making such high puncture techniques dangerous. For example, puncturing above the inguinal ligament can result in occult retroperitoneal haemorrhage which is potentially life-threatening. Calcific plaques on the front wall may also deflect the expected path of the guidewire into the PFA. Not infrequently the guidewire snakes along the back wall instead of bouncing off it.

Salvaging a PFA cannulation involves tentative withdrawal of the sheath, and guidewire, out of the PFA into the CFA and attempting to re-advance the guidewire down the SFA under angiographic guidance. The sheath then follows over the guidewire once access has been secured. During this time the access is most at risk as the sheath can come back out of the puncture site on the vessel. Salvage may also be impossible if the puncture is immediately adjacent to the PFA ostium or if anterior plaque prevents SFA cannulation.

An example of a device within this field is that of <CIT>, which discloses a catheter, having a nosecone formed at the distal end of the catheter body and having a distal opening and a lateral opening. Adjacent inclined surfaces within the catheter enable a guidewire to be directed through the lateral opening of the catheter. Another example is that of <CIT>, which discloses a guide catheter comprising a hollow tubular body defining an internal lumen, a proximal opening and a distal opening. The tubular body includes a distal portion preformed in such a way as to take on a curved configuration with regard to the main axis. A further example is that of <CIT>, which discloses a guide catheter with an end hole and a side hole. The side hole is shaped such that its semi-elliptical when in use, and it is possible to pass the medical instrument through said side hole <NUM> oblique to the centre axis of the device. A yet further example is that of <CIT>, which discloses a retrieval catheter that enables the sheath and dilator to move axially with respect to each other during retrieval, (for example, of a stent).

It is desirable therefore to provide a device or method that facilitates introduction of a cannula or guidewire into the correct bodily lumen, that avoids or ameliorates at least one of the aforementioned disadvantages or at least provides a useful alternative.

Preferred embodiments of the invention are set forth in the dependent claims. Associated methods are also described herein to aid understanding of the invention, but these do not form part of the claimed invention.

References to "embodiments" throughout the description which are not under the scope of the appended claims merely represent possible exemplary executions and are therefore not part of the present invention.

In accordance with the present disclosure there is provided an obturator comprising a hollow distal end portion, the distal end portion comprising:.

Disclosed herein is a sheath, not in accordance with the claims, comprising:.

There is also described an embodiment, not in accordance with the claims, where the end hole and side hole may be accessible from the single lumen.

There is also described an embodiment, not in accordance with the claims, where the distal end portion may comprise an end hole for receipt of the guidewire and being located at the distal end. The end hole may be positioned so that a guidewire extending therethrough extends substantially parallel to a longitudinal axis of the obturator.

The end hole may be offset from the longitudinal axis of the obturator.

There is also described an embodiment, not in accordance with the claims, where the side hole may be located on one side of the obturator so that a guidewire extending through the side hole extends at an angle to the obturator.

The distal end portion may taper towards the distal end.

The side hole may be located proximally of the taper.

There is also described an embodiment, not in accordance with the claims, where the taper may extend from the side hole to this distal end. The taper may instead extend from a location proximal of the side hole, to the distal end.

There is also described an embodiment, not in accordance with the claims, where the side hole may have one of a square, rectangular, triangular shape, circular or elliptical.

The side hole may have a teardrop shape. The teardrop shape may comprise a distally directed apex.

The obturator may further comprise one or more orientation indicia positioned on a proximal portion of the obturator to indicate a location of the side hole around on a periphery of the obturator.

In accordance with the present disclosure there is further described a sheath, that is not in accordance with the claims, comprising:.

so that when the sheath is located in a first bodily lumen, in use, a second bodily lumen can be located by flowing contrast medium through the sheath to exit the side hole.

In accordance with the present disclosure there is further provided a sheath assembly comprising:.

There is also described an embodiment, not in accordance with the claims, where the sheath may be a cannula and the obturator is within the sheath or cannula.

There is further described a method, that is not in accordance with the claims, for inserting a sheath, comprising threading a sheath assembly as described above onto a guidewire and into a bodily lumen of a subject, the guidewire extending into the side hole of the obturator.

There is also described an embodiment, not in accordance with the claims, where the sheath may be a cannula.

There is further described a method for repositioning a guidewire, that is not in accordance with the claims, comprising:
threading, onto a guidewire located in a first (e.g. undesired) bodily lumen, a sheath assembly comprising a sheath and an obturator as described above, the guidewire extending through the side hole of the obturator, the side hole being positioned to redirect the guidewire into the second (e.g. desired) bodily lumen.

'General alignment' may be achieved intracorporeally or by withdrawing the assembly, with the wire through its side hole, off a proximal end of the wire (i.e. the end of the wire located extracorporeally), and reinserting the wire through the end hole of the, or a, sheath assembly to thereby generally align the sheath assembly with the desired bodily lumen.

There is further described a method for repositioning a guidewire, that is not in accordance with the claims, comprising:.

There is further described a method for repositioning a sheath, that is not in accordance with the claims, comprising:.

There is also described an embodiment, not in accordance with the claims, where the obturator comprises an end hole, a side hole and a slit extending between the end hole and side hole, and retracting the sheath assembly along the guidewire until the obturator becomes generally aligned with the second bodily lumen may then comprise retracting at least the obturator until the guidewire is captured in the obturator through the slit.

The invention is illustrated in the <FIG> and <FIG>. The remaining figures illustrate examples that are useful for understanding the invention.

Some embodiments will now be described by way of non-limiting example only with reference to the accompanying drawings in which:.

The present disclosures relates to an obturator, a sheath assembly including such an obturator, and methods for use of the sheath assembly. The sheath assembly will hereinafter be described as a cannula assembly for illustration purposes only. It will be appreciated the present obturator may be useable in other assemblies without departing from the teachings herein.

The obturator comprises at least a side hole, and generally two holes - a side hole and an end hole - through which a guidewire can extend. A first of the holes - the end hole - is positioned generally axially with respect to the cannula assembly. For a correctly positioned guidewire, this first hole will be the only hole used since the cannula, tracking or advancing along the guidewire, will follow the guidewire into the correct (i.e. desired) bodily lumen. For an incorrectly placed guidewire, a second of the holes - the side hole - will be used. Advancing the guidewire through the second hole causes it to extend into the desired bodily lumen. The cannula assembly can then be advanced along the guidewire into the desired bodily lumen.

The obturator is intended to improve the ease and speed of salvaging an incorrectly placed guidewire with minimal change or disruption to existing clinical procedural workflows. The obturator may also assist in securing arterial access while minimising inadvertent loss of access during salvage. An advantage of use of the present obturator when salvaging an incorrectly placed guidewire and sheath assembly is that patients and staff are exposed to reduced unnecessary radiation and iodinated contrast.

In general, the present disclosure will be made with reference to the vasculature of a subject (i.e. patient) and vascular lumina of that vasculature. However, it will be appreciated that the present teachings may be similarly applied to other lumina of the body: for example, it may be similarly applied to other bifurcating vessels in the body, beyond the CFA, including both arteries and veins. For example, it could also be used for selective cannulation in the heart, visceral arteries, upper limbs, carotids, brain etc..

<FIG> illustrates incorrect placement of a guidewire <NUM> (<FIG>) through a needle <NUM>, followed by correct placement of the guidewire <NUM> (<FIG>) resulting from bouncing the guidewire <NUM> off the wall <NUM> of a vascular lumen <NUM> near an ostium <NUM>. In the arrangement shown in <FIG>, the various portions of the vasculature <NUM> are the CFA <NUM>, SFA <NUM> and PFA <NUM>.

Using the obturator disclosed herein, an interventionist or physician may be able to avoid the uncertainty of correct placement resulting from bouncing the guidewire off the vascular luminal wall and other known techniques. An embodiment <NUM> of an obturator in accordance with present teachings is shown in <FIG>. The obturator <NUM> broadly comprises a hollow distal end portion <NUM>, the distal end portion <NUM> comprising a first hole <NUM> and second hole <NUM> both of which are for receiving a guidewire.

The term "receiving" as used in relation to the guidewire can mean that the hole is threaded over a guidewire that has already been located in the subject, or that the guidewire is advanced through the hole, or another meaning as determined by the context in which the term is used.

The obturator <NUM> further comprises a hub <NUM> and grip <NUM>. The hub <NUM> is for connection to a cannula or other medical device, in a known manner. Similarly, the grip <NUM> may take any known shape and is for gripping during removal of the obturator <NUM>.

The distal end portion <NUM> extends from the distal end <NUM>, proximally of the obturator <NUM>. The distal end portion <NUM> tapers towards the distal end <NUM>. The taper <NUM> extends from the distal end <NUM>, proximally of the obturator <NUM>. The taper <NUM> facilitates introduction of the obturator into the subject (not shown).

The distal end <NUM> is sized to have the same, or slightly larger, diameter as the guidewire during use. The subject's skin may resile to circumferentially contact the guidewire after removal of the needle used to place the guidewire. Close conformance of the distal end <NUM> of the obturator <NUM> with the diameter of the guidewire facilitates insertion of the obturator <NUM> into the pre-existing penetration of the patient's skin.

The second hole <NUM>, which may be interchangeably referred to as a side hole or lateral hole, may be located in the taper <NUM>, or proximally of the taper as shown in <FIG>. Locating the second hole <NUM> proximally of the taper <NUM> means the leading edge of the second hole <NUM> can direct the guidewire along a lateral trajectory at a greater angle to the longitudinal axis <NUM> of the obturator <NUM>. In addition, the leading and trailing edges of the second hole <NUM> are at the same diameter, resulting in a lower likelihood of the second hole <NUM> catching on the subject's skin during insertion of the obturator <NUM>.

The first hole <NUM> is located at the distal end <NUM>. The second hole <NUM> is located proximally of the first hole <NUM>. As used herein, the term "proximally" and similar will refer to being located closer to the end of the obturator, cannula or other medical device, at which the physician or interventionist applies manual control of the medical device. Conversely, "distally" and similar refer to being located further from that end. Thus, the distal end of a medical device is the end of that device that is further from the end to which direct manipulation is applied by the physician or interventionist.

The first hole <NUM> is positioned so that a guidewire extending therethrough extends substantially parallel to the longitudinal axis <NUM> of the obturator <NUM>. In some embodiments, the first hole <NUM> is coaxial, or axially aligned, with the longitudinal axis <NUM>. The first hole is offset from the longitudinal axis <NUM> of the obturator <NUM>. Since the obturator <NUM> may be flexible, parallelism and axial alignment may be determined tangentially relative to the distal end <NUM>.

In the present embodiment, the second hole <NUM> is located on one side of the obturator <NUM>. A guidewire extending through the second hole <NUM> therefore extends at an angle to the obturator <NUM>. For illustration purposes, <FIG> shows guidewires <NUM>, <NUM> extending from the first hole <NUM> and second hole <NUM> respectively, in broken lines as they do not form part of the obturator <NUM>.

The second hole <NUM> may take any desired shape. For example, the second hole <NUM> may have a square, rectangular or triangular shape. In the embodiment shown in <FIG>, the second hole <NUM> has a rectangular shape (though exact rectangularity is not required to have a "rectangular" shape).

The second hole <NUM> is located around the periphery of the obturator <NUM>. The second hole <NUM> therefore extends from a hollow internal lumen of the obturator - such as lumen being known in the art - through the wall of the obturator <NUM> so that a guidewire can enter a bodily lumen through the second hole.

The obturator <NUM> of <FIG> further comprises one or more, and presently one, orientation indicia <NUM>. The indicium <NUM> is positioned on a proximal portion of the obturator to assist the physician or interventionist to locate the distal end region in the subject - e.g. in relation to the profunda or SFA. In some embodiments, the indicium may be located towards the distal end of the obturator and be locatable either on fluoroscopy, ultrasound, or by estimation, to provide similar assistance. The indicium <NUM> indicates a location of the second hole around on the periphery of the obturator. This enables the physician or interventionist to know where the second hole <NUM> is located relative to the desired bodily lumen. Where more than one side hole is provided, as discussed below, there may be an indicium per side hole.

9a schematically illustrates a longitudinal cross section of an alternative distal end portion <NUM> of an obturator <NUM> in accordance with present teachings. In one exemplary embodiment the side hole <NUM> may have a configuration of an oval shape. The oval shape has a major axis between <NUM> and <NUM> long - e.g. in a longitudinal direction of the hole <NUM> along the distal end portion <NUM>. The oval shape has a minor axis between <NUM> to <NUM> long - e.g. in the transverse or lateral direction of the hole <NUM> along the distal end portion <NUM>. In other embodiments the side hole may be circular, or elliptical either symmetrically or asymmetrically, triangular, square, rectangular or have a teardrop shape.

The obturator may comprise a single side hole as described with reference to <FIG>. In the present embodiment, the obturator may instead comprise two, three, four or any other number of side holes as required. Presently, the obturator <NUM> comprises four side holes. The side holes are positioned at different distances from the distal tip <NUM> so as not to materially weaken the distal end portion <NUM>. The holes are positioned at <NUM> o'clock (<NUM>), <NUM> o'clock (<NUM>), <NUM> o'clock (<NUM>) and <NUM> o'clock (<NUM>) positions respectively, as best shown in FIG. The holes <NUM> to <NUM> are thus spaced equidistantly about the periphery of the distal end portion <NUM>.

9b is a view along the longitudinal axis of a transverse cross section of the distal end portion <NUM> of the obturator <NUM>. The side hole or side holes may be lined with, or have applied strips or shapes of materials of different densities or characteristics that are radiopaque on fluoroscopy, or strengthen various portions of the respective hole to enable proper independent manipulation of the guidewire and obturator during repositioning of each.

To facilitate selective control of the guidewire through each hole <NUM> to <NUM>, the obturator may comprise a single lumen with quartering mechanism, a dual or triple lumen as desired. Guidewire control and plural lumina are discussed with reference to <FIG>.

9c schematically depicts a longitudinal cross section of the proximal and distal ends of a vascular sheath or cannula <NUM>. The cannula <NUM> comprises, proximally, a haemostasis valve - not shown but well understood in the art - within a hub <NUM>. The hub <NUM> is located outside of the skin during use and is the portion of a cannula assembly (discussed in more detail with reference to <FIG>) through which all cannulations commence.

The cannula <NUM> comprises a lumen <NUM>, and a flushing port (see port <NUM> of <FIG>) which enables fluid or contrast to be aspirated or injected down the lumen <NUM>. The obturator <NUM> is positioned within the lumen <NUM> during use and the fluid or contrast is often injected through the cannula <NUM> and obturator <NUM> into the subject. The fluid or contrast exits either by the longitudinal or first hole <NUM> and through hole <NUM> of the obturator <NUM>, through the side hole <NUM> of the obturator <NUM>, or both.

To facilitate delivery of contrast or fluid, the obturator or obturator insert <NUM> is hollow in its proximal extremity. The obturator may have either a blind end in its distal extremity or else incorporate a diverting or quartering mechanism (described with reference to <FIG>) to divert the guidewire out the desired side hole upon activation of the diverting or quartering mechanism. The diverting or quartering mechanism facilitates replicable diversion of the path of a guidewire into the desired side hole. In the instance of a blind-ending obturator, initial access will be done using a known obturator with a single end-hole as per normal. Upon discovery of a profunda cannulation the obturator and wire will be removed and the blind-ending obturator with side a side-hole will be inserted into the cannula. The entire cannula-obturator assembly will be retracted until the side-hole aligns with the femoral artery bifurcation. The wire will be advanced down the side-hole into the SFA and passed for a substantial distance. The entire assembly will then be withdrawn over the wire out of the patient, and reintroduced along the guidewire using the, or a, know obturator having an end-hole so that in-line cannulation of the SFA is achieved.

The distance between elements <NUM> and <NUM> is between <NUM> to <NUM>. The distance between distal end <NUM> of sheath <NUM> is between <NUM> and <NUM>, and preferably <NUM>.

In one embodiment, the sheath <NUM> may be tapered towards the distal tip or end <NUM>, leading to the exit or longitudinal hole <NUM>, resulting in the hole <NUM> being considerably narrower than the lumen <NUM> of the sheath <NUM>. The gauge of the sheath <NUM> may be suitable for common peripheral vascular interventions, for example between but not limited to 4Fr and 10Fr.

<FIG> illustrates a cannula assembly <NUM> comprising a cannula <NUM> and an obturator <NUM> as described with reference to <FIG>. <FIG> shows how the hub <NUM> of the obturator <NUM> engages with a hub <NUM> of the cannula <NUM>.

The distal end portion <NUM> of the obturator <NUM> protrudes distally of the cannula <NUM>. The distal end portion <NUM> thereby enters the subject first, widening the penetration formed in the subject and facilitating easier entry of the cannula <NUM> into the subject.

In this embodiment, the distal end portion <NUM> protrudes sufficiently that the second hole <NUM> is located distally of the cannula <NUM>.

The cannula assembly <NUM> also includes an infusion assembly <NUM>. The infusion assembly <NUM> comprises a valve <NUM> and extension tube <NUM>, extending into a side port or infusion port <NUM> of the cannula hub <NUM>.

The entire complex - i.e. obturator, cannula and other of the cannula assembly - can be made from hypoallergenic, inert, flexible and stretchable materials such as silicone or polymers such as polyurethane.

The obturator <NUM>, <NUM> of <FIG> and <FIG> each comprise a distinct and separate first hole and second hole. In contrast, the obturator <NUM> of <FIG>, which is received within a cannula <NUM>, comprises a slit <NUM> extending between the first hole <NUM> and second hole <NUM>. The relevance of the slit <NUM> will be explained with reference to <FIG>.

The cannula <NUM> of <FIG> tapers towards the obturator <NUM> such that the diameter of the cannula <NUM> at its distal end is the same as the outer diameter of the obturator <NUM> when the two are assembled together. In other cases, the cannula <NUM> may be a sufficiently tight fit around the obturator <NUM> to substantially avoid catching on tissue of the subject during insertion and use.

The obturators <NUM>, <NUM> of <FIG> and <FIG> both included a substantially rectangular side or second hole <NUM>, <NUM> as shown in <FIG>. In other embodiments, the side or second hole <NUM> may have a teardrop shape as shown in <FIG>. The teardrop shape of the side or second hole <NUM> comprises a distally directed apex <NUM>. Thus, the apex <NUM> points towards the distal end <NUM> of the obturator <NUM>. In other alternatives, the apex may be oriented proximally, or is some other desired orientation.

The teardrop shape self-centres the guidewire (not shown) in the second hole <NUM> when the guidewire extends therethrough. Where a slit is used in conjunction with the teardrop shape, the teardrop shape also facilitates reintroduction of the guidewire into the obturator after repositioning of the guidewire from the undesired lumen of the subject, into the desired lumen. The teardrop shape can permit more gradual bending of the guidewire as it exist the side hole, but may be more difficult to manufacture than a rectangular or other shape side hole.

<FIG> shows various embodiments on distal end portions of obturators in accordance with present teachings, each of which is shown extending from a cannula. Each distal end portion tapers towards its respective distal end - e.g. towards the diameter of a guidewire received through the obturator. In some embodiments, however, the distal end portion may be blunt - for example, sized to have the same or similar internal diameter as the outer diameter of a guidewire extending therethrough.

The distal end portions shown in <FIG> each comprise a second tapered region <NUM>. The second hole <NUM> may be located in the taper described with reference to <FIG>, in the second tapered region <NUM> or between the tapered regions as shown.

<FIG>and <FIG>each show rectangular second holes, such a shape being shown in exploded view in <FIG>. Similarly, <FIG> shown teardrop second holes, such a shape being shown in exploded view in <FIG>.

<FIG>shown the second hole located closer to the distal end of the distal end portion than in <FIG>.

<FIG> each show embodiments where the first and second holes are connected by a slit <NUM> for return of the guidewire into the obturator lumen (i.e. that which leads to the end hole). As described with reference to <FIG>, during repositioning of the obturator onto an already repositioned guidewire the slit flexes around the guidewire. The closer the second hole is to the distal end of the obturator, the greater the force that may be applied to the internal wall of the vasculature during repositioning of the obturator. It can therefore be desirable to locate the second hole further proximally in the distal end portion. This would also make it easier to anchor the obturator in the undesired lumen in vivo, while relocating the guidewire.

<FIG> shows a flowchart <NUM> of workflows performed during cannulation. To commence cannulation a puncture is formed in the subject's or patient's skin, and into the vasculature - step <NUM>. In general, the puncture will be a micro-puncture formed by a needle (not shown). A guidewire is then advanced through the needle and into the vasculature - step <NUM>. After step <NUM>, the needle will generally be removed from the guidewire and a sheath (i.e. cannula assembly) threaded onto, or introduced over, the guidewire and into the vasculature - step <NUM>.

The physician then checks whether the cannula assembly is in the correct or desired vascular lumen - step <NUM>. With reference to <FIG>, this would place the cannula assembly in the SFA. This check can be performed using contrast medium injected into the cannula assembly - e.g. through extension tube <NUM> of <FIG>. The contrast medium can be detected using known methods. The check may also be performed manually, by palpation.

If the cannula assembly has entered the desired lumen, then the procedure (e.g. angioplasty) continues - step <NUM>. This will involve removal of the guidewire and obturator from the cannula, and insertion of another device - e.g. a catheter - through the cannula and into the desired vascular lumen.

If it is determined that the cannula assembly has been advanced into the undesired lumen, the guidewire is retracted into the cannula assembly - step <NUM>. The guidewire is retracted until the tip of the guidewire is aligned with, or is proximal of to, the second hole of the obturator.

The guidewire is then advanced through the second hole of the cannula assembly and into a second or desired bodily lumen of the subject - step <NUM>. The guidewire is thus repositioned into the desired bodily lumen.

Relevantly, the cannula assembly used up to, and including, the determination step <NUM> may be a standard cannula assembly known in the art - i.e. a cannula assembly comprising only a single hole in the obturator, that hole being coaxial with a longitudinal axis of the obturator. Upon determining that the guidewire is in the undesired lumen, that cannula assembly may be removed and unthreaded from the guidewire and a cannula assembly as taught herein then threaded onto the guidewire. Alternatively, a cannula as taught herein may be used from the outset.

In accordance with step <NUM>, the cannula may then be repositioned - e.g. into the desired lumen. This is achieved by retracting the cannula assembly (i.e. sheath) over or along the guidewire. Retraction occurs until the obturator becomes generally aligned with the desired bodily lumen. The term "aligned" in this circumstance means that upon advancing the cannula assembly back along the guidewire, the obturator, and thus the cannula, will be guided into the second, or desired, bodily lumen. The procedure may then continue as usual - step <NUM>.

<FIG> thus illustrates the normal or common workflow and a workflow involving repositioning the cannula assembly with minimal disruption to the common workflow. With reference to <FIG>, the puncture site may be secured by the method <NUM> - i.e. not require a further puncture to be made for repositioning - by having obturator and guidewire operated in a manner that changes the direction of the guidewire while maintaining the sheath inside the PFA. The sheath is only removed from the PFA once the guidewire is safely secured in the SFA. With the guidewire in the SFA, secured by the sheath, the physician or interventionist can now proceed with lower limb angioplasty or some other procedure.

The steps of the workflow <NUM> involving the cannula assembly described herein, comprising two holes in the obturator (though the obturator may also comprise more than two holes) are mainly involved in steps <NUM> to <NUM>. It will be appreciated that a procedure may instead comprise two obturators, one in which the distal end portion comprises only a side hole located proximally of the distal end, for directing the guidewire laterally from the obturator, and a separate obturator comprising and end hole.

<FIG>, comprising <FIG>, illustrates various steps of the workflows of <FIG>, or states of the sheath assembly during performance of those workflows. <FIG> shows a sheath assembly located in the undesired lumen <NUM> as determined at step <NUM>. <FIG> shows the guidewire <NUM>, after retraction and reinsertion or re-advancement along the sheath assembly, extending through the side hole <NUM>. <FIG> shows how the guidewire <NUM> will rest on the desired lumen <NUM> after advancing through the side hole. <FIG> shows the obturator <NUM> retracted so that its distal end <NUM> is proximal the ostium <NUM> between the desired lumen <NUM> and undesired lumen <NUM>. This retraction step occurs between introduction of the guidewire <NUM> into the desired lumen <NUM> - steep <NUM> - and retraction of the sheath <NUM> - step <NUM>. In this condition, the obturator <NUM> and guidewire <NUM> will be side-by-side in the sheath <NUM> as shown in <FIG>. The obturator <NUM> and sheath <NUM> are then advanced back along the guidewire <NUM> into the desired lumen <NUM> - <FIG>.

In an alternative embodiment, the obturator <NUM> includes a slit <NUM> between the end hole <NUM> and side hole <NUM> as shown in <FIG>. After repositioning the guidewire <NUM> through the side hole <NUM>, the guidewire <NUM> is located immediately distally of the side hole <NUM> in the position generally indicated by <FIG>. As the obturator <NUM> is retracted, as shown progressively in <FIG>, the guidewire <NUM> flexes the edges of the slit <NUM> inwardly until the guidewire <NUM> pushes back into the lumen <NUM> of the obturator <NUM>. The final position of the obturator <NUM> during retraction, with the guidewire <NUM> in the lumen <NUM>, is shown in <FIG>. Thus, advancing the obturator <NUM> will result in it following the trajectory of the guidewire <NUM> into the desired lumen <NUM>.

With further reference to <FIG>, after the guidewire <NUM> exits the side hole <NUM> into the second or desired bodily lumen <NUM>, the sheath assembly is retracted along the guidewire <NUM> until the guidewire <NUM> and extended distal taper of the obturator <NUM> - i.e. the taper between the side hole <NUM> and distal end - are wedged within the sheath. In some cases, if the distal taper is long enough, the guidewire <NUM> will not be recaptured in the obturator <NUM> at this stage. Instead, the two wedge into the sheath due to the reduce cross section of at the distal taper. This wedging facilitates removal of the obturator <NUM> out of the sheath assembly while leaving the guidewire <NUM> in the second or desired bodily lumen <NUM>.

<FIG> illustrate a variety of quartering systems each comprising a quartering mechanisms and in some cases one or more elements for enabling, aiding and/or facilitating control of the quartering mechanism and thus of the guidewire selectively between end (or first) and side (or second) holes. The quartering system in each case is part of the obturator <NUM>, <NUM>. <FIG> itself illustrates more than one quartering system. It will be appreciated that, in practice, only a single such quartering system will typically be provided.

In one embodiment, the quartering mechanism is a contoured protrusion <NUM>. The contoured protrusion is diametrically opposite the side hole <NUM> (e.g. if the side hole <NUM> is at <NUM> o'clock then the protrusion <NUM> is at <NUM> o'clock). The protrusion <NUM> is relatively proximal to the side hole <NUM>. The protrusion <NUM> preferably slightly overlaps the side hole <NUM> such that it deflects the guidewire (not shown) into the side hole <NUM>.

The shape of the protrusion <NUM> may be a symmetrical or asymmetrical hump, or ledge, or wedge. The surface of the protrusion <NUM> may be smooth, rough or grooved. The protrusion may be inflatable, e.g. using air or a liquid, through a conduit (not shown) so as to have a collapsed state permitting preferential access of the guidewire through one of the side and end holes - presently the end hole <NUM> described with reference to FIG. 9a - and an inflated or expanded state directing the guidewire through the other of the side and end holes - presently the side hole <NUM> as described with reference to FIG. Expansion and collapse of the protrusion <NUM> may be performed in the same manner as expansion and collapse of a balloon catheter in a known manner.

In an alternative embodiment, a flap/leaflet <NUM> may be used. The flap <NUM> is located distally of the side hole <NUM>. The flap <NUM> can be either oriented to occlude the main lumen <NUM>, for instance by flipping up (on a hinge, living hinge or otherwise) to force passage of the guidewire through the side hole <NUM>, or oriented to permit passage of the guidewire down to the distal end of the main lumen <NUM>. The flap <NUM> may take a substantially planar form, may be a ball-valve mechanism rotated between a position in which the hole through the ball of the valve aligns with the main lumen <NUM> - permitting passage of the guidewire through the ball-valve - and a position in which the hole is out of alignment (e.g. perpendicular to) with the lumen <NUM> to prevent access to the distal end. Rotation of the mechanism <NUM> may be achieved by control wires and similar, presently used to control implant and removal of medical devices in the vasculature in a known manner. The flap <NUM> may instead change elasticity or stiffness to afford greater resistance to passage via an activating mechanism (not shown). The change in elasticity or stiffness may be affected either electrically (e.g. using an elastomer that change properties upon electrical stimulation, such as carbon black filled ethylene-propylene based elastomer (cPBE) embedded in a electrically insulating sheet of polydimethyl siloxane), or mechanically (e.g. by coiling up a very fine helical wire within the flap or inflating the flap body), as will be understood by the skilled person in light of the present teachings.

In yet a further alternative embodiment, an expanding circumferential ring or doughnut <NUM> is provided. The expanding ring <NUM> can be expanded to occlude the distal lumen upon activation, and thereby force the guidewire through the side hole <NUM>. Upon activation - e.g. inflation in the same manner as a balloon catheter - the ring <NUM> significantly narrows the lumen <NUM> to occlude it and preferentially preclude a guidewire from advancing down the lumen <NUM> - e.g. force the guidewire out the side hole <NUM>. Similarly, feature <NUM> is a ring <NUM> is inside the wall <NUM> of the sheath. The ring <NUM> is constricted upon activation - e.g. by pulling a wire that shortens the circumference of the ring <NUM> - to occlude the main lumen <NUM> and direct the guidewire out the side hole <NUM>.

<FIG> show a dirigible device <NUM> immediately distal to the side hole <NUM>. A small channel <NUM> is embedded inside the wall <NUM> of the sheath (e.g. vascular sheath). The channel connects the dirigible device <NUM> to the proximal portion (see hub <NUM> of <FIG>) of the sheath. This channel <NUM> enables the transport of medium such as fluid or air to the dirigible device to manipulate and adjust its size as seen in <FIG> in which it is inflated, and <FIG> in which it is deflated. Similar mechanisms can be used for inflation/deflation and control of other mechanisms described with reference to <FIG>.

In an alternative embodiment, the quartering mechanism for guiding the guidewire to the side hole utilizes an intraluminal inflatable or bag that is meant to act as a dirigible device as discussed with reference to <FIG>. This dirigible apparatus is connected to the outside via a channel embedded inside the wall of the vascular sheath and can be activated via the injection of medium such as saline, contrast or gas such as carbon dioxide.

Upon activation, this dirigible device will expand and occlude the lumen of the vascular sheath completely. Additionally, the expansion may also stretch the sheath in the immediate vicinity and secondarily expand the width of the side hole to facilitate the guidewire tip cannulating this newly enlarged opening. In addition, if the main lumen is completely occluded, contrast can be flushed via the side hole to visualize the ostium of the profunda or undesired lumen.

It will be appreciated that the location of the quartering mechanisms and other elements of the quartering systems shown in <FIG> may not be exactly as shown in relation to the side hole <NUM>, <NUM>, <NUM>. However, placement of those quartering mechanisms to achieve the purpose of directing the guidewire through the side hole <NUM>, <NUM>, <NUM> will be clear to the skilled person in light of the present teachings.

One or more obturators may instead be used as part of the quartering system. With reference to <FIG>, the distal end <NUM> of an obturator <NUM> is designed to fit snugly inside the lumen of the vascular sheath - see, e.g. <FIG>. The tip of the obturator <NUM> maybe tapered or bullet shaped to facilitate puncturing of the arterial wall, during entry into the vasculature, or the wall of another bodily lumen as required. In some embodiments the obturators may have a slightly larger gauge than the sheath and upon entering the lumen of the sheath may dilate and stretch the wall of the sheath.

The obturator <NUM> comprises a lumen <NUM> having a side hole <NUM>, with the distal end <NUM> being blind. In some cases, an obturator having only and end hole - e.g. a traditional obturator - may be used until it is determined that the obturator has entered an incorrect bodily lumen. That obturator may then be removed and obturator <NUM> threaded onto the guidewire. The intention of using obturator <NUM> is to shift the end of the guidewire into the desired bodily lumen. The cannula assembly can then be advanced along the correctly placed guidewire.

The side hole <NUM> may be oval, elliptical, quadrilateral or otherwise.

In an alternative embodiment shown in <FIG>, the side hole <NUM> may be in alignment with the end hole <NUM> of the obturator <NUM>, off the main internal lumen <NUM> as shown in <FIG>. While the end hole is not strictly at the very distal end of the obturator, it is forward facing with respect to the longitudinal axis of the obturator and will be referred to herein as an end hole. Also, alignment of the end hole and side hole refers to both being located in generally the same plane defined by the longitudinal axis of the obturator and a radial line normal to the longitudinal axis. Moreover, both the side and end hole are to one side of the longitudinal axis. The main internal lumen <NUM> may come out at or near the edge of the distal end <NUM>, offset from the midline as shown in <FIG>. A quartering mechanism described with reference to <FIG> may be used to direct the guidewire between hole <NUM> and hole <NUM>.

In <FIG>, the proximal lumen is at <NUM> o'clock and the distal lumen is central.

<FIG> illustrates an embodiment of on obturator <NUM>, particularly the distal end portion <NUM>, comprising two separate lumina <NUM>, <NUM>. The lumina <NUM>, <NUM> can be cannulated individually. For example, initially (e.g. at step <NUM>) the sheath will be threaded over the guidewire with the guidewire extending into end hole <NUM>. Once it is determined that the guidewire has been incorrectly positioned in the undesired bodily lumen, then the obturator <NUM> is retracted while leaving the cannula or sheath in position. The obturator <NUM> is removed from the guidewire and re-threaded back onto the guidewire with the guidewire extending through the side hole <NUM>. When the obturator <NUM> emerges through the distal end of the sheath, with the side hole <NUM> oriented towards the desired bodily lumen, the guidewire will be flexed back out of the undesired bodily lumen into the desired bodily lumen. The sheath assembly can then be advanced into the desired bodily lumen.

For this to be achieved, there will generally be some flex or spare space within the sheath to permit that portion of the obturator between the side hole <NUM> and tip <NUM> to progress through the sheath next to the guidewire. Alternatively, a groove <NUM> (see <FIG>) may be incorporated into the portion of the obturator, in which the guidewire is received during advancement of the obturator <NUM> along the sheath.

One lumen <NUM> is shorter than the other <NUM>, and exits side hole <NUM> whereas the other lumen <NUM> is longer and exits centrally at hole <NUM> at the distal end <NUM> of the obturator <NUM>.

<FIG> describes an obturator <NUM> with a diverting lumen <NUM> to attain side hole <NUM> cannulation of the bodily lumen as before, with the difference that the distal lumen continues with an abrupt taper to end hole <NUM>. This results in straight cannulation only being possible with a fine wire (eg <NUM>" or <NUM>"). End hole <NUM> has a smaller diameter than side hole <NUM>. Thus, standard wires (ie <NUM>") will be diverted out the side hole <NUM>. This would allow preservation of wire access in the PFA while simultaneously enabling preferential cannulation into the SFA. It will be appreciated that a similar arrangement could allow preferential straight cannulation, by providing an end hole with a larger diameter than the side hole. A correspondingly larger diameter lumen will need to extend to the end hole, than the diameter of the lumen extending to the side hole, from the main lumen. Moreover, the internal lumen of the obturator may permit simultaneous positioning of a fine guidewire into the smaller diameter hole, and of a larger guidewire through the larger diameter hole. In addition, even where the holes are the same size or otherwise, the positioning of a guidewire in one hole may force a second guidewire to exit the other hole.

The present disclosure, particularly <FIG>, also discloses a sheath <NUM>. The sheath <NUM> comprises a side hole <NUM> and a distal end <NUM>. In use, if an obturator (whether as taught herein or known), with the guidewire threaded through its end hole, is used with sheath <NUM> and it is determined the sheath is in the undesired lumen, the obturator can be removed. Contrast medium is then flowed (e.g. injected) through the sheath <NUM>. The contrast medium will exit the distal end <NUM> if that end <NUM> is open. The contrast medium will not exit the distal end <NUM> if the distal end is blind (i.e. closed). In both cases, contrast medium will exit the side hole <NUM>. The sheath <NUM> can then be moved, if necessary, until the side hole <NUM> is aligned with the desired lumen as indicated by contrast medium flowing out the side hole into the desired lumen, the contrast medium being visualised in a known manner. The guidewire can then be removed, an obturator as taught herein inserted, and the guidewire threaded so that its side hole aligns with the side hole <NUM> of the sheath - e.g. as determined when the hub of the obturator meets the hub of the sheath, or by providing indicia on one or both of the obturator and sheath to indicate the relative alignment of the side holes. The guidewire is then threaded through the side hole of the obturator to project from the side hole of the sheath <NUM> into the desired lumen. The sheath assembly may then be withdrawn and to relocate the sheath and/or sheath assembly on the guidewire such that the guidewire projects distally of the sheath <NUM>, which can then be advanced into the desired lumen. The sheath <NUM> may be a cannula or cannulation catheter, or other medical device.

<FIG> illustrates how the obturator will be positioned in situ with the distal end <NUM> within the profunda or PFA <NUM>, and the guidewire <NUM> within the SFA <NUM> after cannulating the side hole <NUM>. For illustration purposes, the hub <NUM>, CFA <NUM> and cannula <NUM> are also shown.

The obturators, sheath/cannula assemblies described herein enable easy cannulation of the "side hole" on the obturator by engaging the guidewire and diverting its direction from within the vascular sheath to exit more proximally the body of the obturator at an angle to the obturator. The guidewire is thereby intended to pass distally down the SFA.

In some embodiments, a combination of a vascular sheath and a hollow shafted but blind-ending obturator can be used, the obturator having a side exit a distance away from the blind end. Of note, the side hole on the obturator is equal or larger than the dimension of the side holes on the sheath. The blind-ending obturator shaft may be made of materials that are stiffer and may be of a diameter slightly larger than that of the vascular sheath to allow the obturator to dilate and stretch the outer sheath when the obturator is inserted inside the sheath.

This is depicted in <FIG> in which the side hole of the obturator and the side hole of the sheath are orientated and aligned by, for example, using one or more indicia such as external markings, or radiopaque markings visible on x-ray. In some other embodiments, haptic feedback can be used - e.g. a "click" and partial lock/grip when the obturator is aligned with the cannula. In this preferred embodiment, the side hole on the sheath may be about <NUM> to <NUM> from the distal tip. The obturator with the blind ending tip is slightly longer than the length of the vascular sheath between the proximal hub and the furthest side hole. In a variation of this embodiment, the obturator may have a smaller distal channel or lumen to enable introduction of the obturator through the sheath over an existing fine wire located within the PFA, such that the SFA can be preferentially cannulated through the side hole using a larger wire - e.g. two wires may be within the obturator, one fine wire extending distally from the end hole and the other, larger wire extending laterally from the side hole - see <FIG>.

The perceived workflow for use of said obturator would be, in the case of the blind-ending obturator for the wire to be removed leaving the sheath in the PFA:.

In the case of a fine-hollow obturator the existing wire would be changed to a <NUM>" (<NUM>) or smaller wire to maintain access in the undesired lumen - e.g. the PFA - and the obturator advanced or railed over the wire to end in the desired lumen - e.g. the SFA - as before. The remainder of the workflow would remain the same. Insertion of a second wire would now cause diversion down the side hole.

In an alternative embodiment, the side hole may incorporate a mechanism for detection of the edge of the puncture, for instance by flashback, or cessation thereof, of blood up a suction channel, or else by injection of contrast down an injectable channel, which may allow for activation of a separate mechanism for suture or otherwise closure of the puncture site, not described here.

It is envisioned that contrast will be flushed through either both the distal end and side holes, or else preferentially through one or the other, to demonstrate that the side hole is sitting proximal to the bifurcation of CFA into SFA and PFA - i.e. the bifurcation between the desired and undesired lumina - and in position for wiring. It is also envisioned that radiopaque markers on the side of the sheath will enable the operator to easily align the side hole with the opening of the undesired lumen by rotating the sheath until the marker is in the appropriate position.

It is further envisioned that, in some embodiments, the sheath will be withdrawn over the guidewire, now extending into the desired lumen, in its side hole and reintroduced via the wire in its main, working or longitudinal central lumen so that work may continue down the desired lumen and more distally.

Claim 1:
An obturator (<NUM>) comprising a hollow distal end portion (<NUM>), the distal end portion (<NUM>) comprising:
a single lumen (<NUM>);
a distal end (<NUM>);
an end hole (<NUM>) at the distal end, for receipt of a guidewire extending through the single lumen; and
a side hole (<NUM>) located proximally of the distal end (<NUM>), the side hole being for receipt of a guidewire (<NUM>, <NUM>) extending through the single lumen (<NUM>) and to direct the guidewire (<NUM>, <NUM>) laterally from the obturator (<NUM>), the side hole (<NUM>) further being located so that when the obturator is located in a first bodily lumen, in use, a second bodily lumen can be located by flowing contrast medium through the obturator to exit the side hole, characterised in that the obturator further comprises a slit (<NUM>) extending between the end hole (<NUM>) and side hole (<NUM>).