US20160242943A1

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Publication number: US20160242943A1
Application number: US14/969,073
Authority: US
Inventors: Kelley Jean Riedy; Elizabeth Anne Hudson; Thomas Wayne McGhie
Original assignee: Cook Medical Technologies LLC
Current assignee: Cook Medical Technologies LLC
Priority date: 2015-02-20
Filing date: 2015-12-15
Publication date: 2016-08-25
Also published as: US10543117B2; US20190274856A1; EP3058902A1; EP3058902B1

Abstract

A duet stent deployment system is used in a transjugular intrahepatic portosystemic shunt procedure. The device has a versatility of adjusting to a patient's anatomy in vivo. The system includes exactly two self expanding stents mounted on an inner catheter and covered by an outer sheath that is moved among a pre-deployment configuration, a first deployment configuration and a second deployment configuration to position the stents in an overlapping configuration from the portal vein, through a shunt and into the hepatic vein, and terminating at the junction with the vena cava.

Description

TECHNICAL FIELD

The present disclosure relates generally to a duet stent deployment system that carries exactly two self expanding stents, and more particularly to a stent deployment system for transjugular intrahepatic portosystemic shunting procedures.

BACKGROUND

Transjugular intrahepatic portosystemic shunting (TIPS) is an artificial channel within the liver that establishes communication between the portal vein and the hepatic vein. TIPS is sometimes used to treat portal hypertension that is often due to liver cirrhosis, which frequently leads to intestinal bleeding, esophageal bleeding and the build up of fluids within the abdomen. The TIPS procedure works by gaining access to the liver via the jugular vein, and then moving through the vena cava to the hepatic vein. A needle is then used to create a point of access (shunt) from the hepatic vein through the liver tissue into the portal vein. A guide wire is introduced to maintain access, and then a balloon catheter is placed over the wire and into the liver tissue. The balloon is inflated in the shunt to create a conduit that will accommodate the forthcoming stent. The balloon is deflated and removed. A stent introducer is then inserted and the portal end of the stent is deployed. The rest of the stent is then released and the balloon is reinserted and reinflated to assure that the stent is fully patent. The stented shunt allows for pressure relief in the portal vein, and blood can return to mostly a normal path through the liver, and therefore reduce some of the symptoms described above.

There are a variety of problems associated with the current TIPS procedure. One problem is that the stent length and sometimes diameter needed for a patient is uncertain, even with careful measuring and estimation. Physicians would like to control the length and diameter of the stent during and post-procedure. For instance, due to substantial variations among patients' internal anatomy geometry, stent sizing can require that a hospital maintain a wide variety of stent introducers with stents of varying lengths to accommodate all potential patients. In addition, when it is necessary for the physician to complete the procedure with the implantation of two stents, the first stent introducer must be withdrawn and a second stent introducer must be brought into the patient, increasing costs, procedure times and complication risks to the patient. An additional problem is that this procedure is expensive due to physician operating time and materials. Lastly, a covered stent is often integral to the procedure, and physicians generally prefer longer sleeve covered stents. These covered stents have an outer coating that keeps bile out of the shunt, and may include an inner coating that promotes platelet growth and blood flow. European patent application EP 1044663A2 is of interest for teaching a sleeved intrahepatic endoprosthesis (stent) in which two members can be connected telescopically to adapt to the length of stenting required for a particular patient. However, this reference teaches mounting the two stent members on separate delivery devices requiring withdrawal of the first delivery device before the second stent can be implanted using a second delivery device.

The present disclosure is directly toward one or more of the problems set forth above.

SUMMARY OF THE DISCLOSURE

In one aspect, a duet stent deployment system includes exactly two stents mounted on a distal segment of an inner catheter. The two stents include a primary stent and a secondary stent. An outer sheath is slidably mounted on the inner catheter, and movable along an axis of the inner catheter from a pre-deployment configuration to a first deployment configuration, and then from the first deployment configuration to a second deployment configuration. The primary and secondary stents are covered by the outer sheath in the pre-deployment configuration. The primary stent is uncovered but the second stent remains covered by the outer sheath in the first deployment configuration. The primary and secondary stents are uncovered by the outer sheath at the second deployment configuration. The primary stent includes a sleeve covering, and the secondary stent is longer than primary stent, and both the primary stent and the secondary stent are self expanding stents.

In another aspect, a method of performing a TIPS procedure includes maneuvering the duet stent deployment system in the pre-deployment configuration to a position at which the primary stent is positioned within a shunt extending between a hepatic vein and a portal vein. The duet stent deployment system is re-configured from the pre-deployment configuration to the first deployment configuration to release the primary stent in the shunt. The duet stent deployment system is then re-positioned to a position at which the distal end of the secondary stent is positioned inside the primary stent, and a proximal end of the secondary stent is positioned at a junction at the hepatic vein to the vena cava. The duet stent deployment system is then reconfigured from the first deployment configuration to the second deployment configuration to release the secondary stent to extend from the junction to the position inside the primary stent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a duet stent deployment system in a pre-deployment configuration;

FIG. 2 is an enlarged partially sectioned view of the distal segment of the duet stent deployment system ofFIG. 1;

FIG. 3 is a side view of the duet stent deployment system in the first deployment configuration;

FIG. 4 is a side view of the duet stent deployment system in the second deployment configuration;

FIG. 5 is a schematic view of a patient's vascular system in the area where a TIPS procedure according to the present disclosure is being performed;

FIG. 6 is a schematic view similar toFIG. 5 after deployment of the primary stent has been initiated;

FIG. 7 is a view similar to viewFIGS. 5 and 6 after the primary stent has been deployed but before deployment of the secondary stent; and

FIG. 8 is a view similar toFIGS. 5-7 except showing the procedure after deployment of the secondary stent with the deployment system being withdrawn upward through the patient's vena cava.

DETAILED DESCRIPTION

Hospitals that perform TIPS procedures must normally inventory stent introducers with stents having a variety of lengths to accommodate both physician discretion in deciding a stenting length needed for a particular patient, as well as accommodating the substantial variety in different lengths among patients from a junction of the shunt with the portal vein to a junction of the hepatic vein with the vena cava. Because of the three dimensional structure of these passageways, It can often be time consuming to determine precise stenting length requirements for each individual patient. In many instances, the physician will implant a first sleeve covered stent in the newly made shunt with a first stent deployment device and then reenter with a second stent deployment device to place a second stent to extend from the shunt through the hepatic vein to the junction with the vena cava. While the first stent length is somewhat typical among patients, and being on the order of about four centimeters in length, the length of a second stent, if any is used, can vary substantially among different patients. The second stent being maybe on the order of 5-8 centimeters in length in order to accommodate most patients. The duet stent deployment system of the present disclosure allows for inventorying only a single device that inherently has the flexibility to accommodate the different stenting needs of particular patients, as well as provide the physician with the option of implanting a second stent in an overlapped configuration with the first stent to provide an overall stented length capability for virtually any patient anatomy. Furthermore, the duet stent deployment system can reduce procedure time over prior art TIPS procedures that require entering the patient multiple times with more than one stent deployment system. The duet stent deployment system of this disclosure can also help in reducing guess work in determining an appropriate length for a second implanted stent, if any.

Referring initially toFIGS. 1-4, a duetstent deployment system30 includes exactly twostents60 mounted on adistal segment35 of aninner catheter31. The twostents60 include aprimary stent61 and asecondary stent62. Theprimary stent61 includes a sleeve covering64, which prevents fluid communication between the lumen defined byprimary stent61 and the surrounding tissue. The sleeve covering64 may be made from PTFE, poly(ether)urethaneurea or an other biocompatible material. The secondary stent may include a sleeve covering that is identical to that of the primary stent, or may have a different sleeve covering, or no sleeve covering at all. In general, the sleeve covering the primary stent may be non-porous to prevent bile from leaking into the stent and therefore into the blood stream. An inner layer of the sleeve covering may be porous to allow platelets to attach. Thesecondary stent62 will always be longer than theprimary stent61, and both theprimary stent61 and thesecondary stent62 are self expanding stents of a type well known in the art. For instance, bothprimary stent61 andsecondary stent62 as well as duetstent deployment system30 may have features similar to currently available ZILVER® available from Cook Incorporated of Bloomington Ind. The length of the primary stent according to this disclosure excludes the length of anyanchoring mechanism63, if any, of the first stent. Whileprimary stent61 may include ananchoring mechanism63,secondary stent62 will not. Thus, the length of the first stent may be determined according to this disclosure by measuring a length of its sleeve.

Anouter sheath40 is slidably mounted on theinner catheter31, and is movable along anaxis41 of theinner catheter31 from apre-deployment configuration42 to afirst deployment configuration43, and then from thefirst deployment configuration43 to asecond deployment configuration44. As shown inFIGS. 1 and 2, the primary and

secondary stents

61,62 are both covered by theouter sheath40 in thepre-deployment configuration42. As shown inFIG. 3, theprimary stent61 is uncovered but thesecondary stent62 remains covered by theouter sheath40 in thefirst deployment configuration43. As shown inFIG. 4, the primary and

secondary stents

61,62 are both uncovered by theouter sheath40 at thesecond deployment configuration44.Outer sheath40 may be on the order of 80-125 centimeters in length, and may have an outer diameter on the order of 10 French, but other sizing would also fall within the scope of the present disclosure.

In one specific example, theprimary stent61 may be about four centimeters long, and the secondary stent is less than eight centimeters long, but still longer than theprimary stent61. As used in this disclosure, the term “about” means that the number is rounded to a single significant digit. Thus, both 3.5 centimeters and 4.4 centimeters are about four centimeters according to the present disclosure. As is typical in known stent deployment systems, the duetstent deployment system30 of the present disclosure may include aradiopaque marker51 on the distal end ofouter sheath40. In addition,inner catheter31 may include a lumen sized to receive a wire guide that is used to gain access to the stenting location in a manner well known in the art. Duetstent deployment system30 may also be similar to typical stent deployment systems by the inclusion of aport38, which is shown capped, to allow fluids to be injected through the space between theinner catheter31 andouter sheath40 in a known manner.Primary stent61 andsecondary stent62 may have identical expanded outside diameters which are typical for TIPS procedures. For instance, the expanded outside diameters may be 8 or 10 millimeters, but other diameters could be utilized without departing from the intended scope of the present disclosure.

In the duetstent deployment system30 shown inFIGS. 1-4, ahub32 is attached to aproximal end33 of the inner catheter.Outer sheath40 is connected to ahandle46 that is slidably mounted on theinner catheter31. While this type of pin and pull actuation may be typical and well known in the art, other actuation structures that allow movement ofouter sheath40 with regard toinner catheter31 would also fall within the inner intended scope of the present disclosure. For example, one handed devices that utilize a pull connected to the outer sheath that moves responsive to a thumbwheel would also fall within the intended scope of the present disclosure.

Duetstent deployment system30 may include afirst lock47 that is movable between a locked position in contact withhandle46 as shown inFIG. 1 and an unlocked position detached fromhandle46.Duet stent deployment30 may also include asecond lock48 that is likewise movable between a locked position in contact withhandle46 as shown inFIG. 1 and an unlocked position detached fromhandle46.First lock47 and thesecond lock48 may interact with a stop34 (hidden from view), which may take the form of an enlarged diameter piece attached toinner catheter31.Lock47 may inhibit movement ofouter sheath40 with regard toinner catheter31 such as whenduet deployment system30 is in itspre-deployment configuration42. Those skilled in the art will appreciate that duetstent deployment system30 will likely be in itspre-deployment configuration42 during shipping, storage and while being maneuvered to a treatment site within a patient. In practice, theduet deployment system30 is locked against movement from thepre-deployment configuration42 to thefirst deployment configuration43 when thefirst lock47 is in the locked position as shown inFIG. 1. Likewise, the duetstent deployment system30 is locked against movement from thefirst deployment configuration43 to thesecond deployment configuration44 when thesecond lock48 is in the locked position as shown inFIG. 3. While

locks

47 and48 may be preferred, they are by no means necessary to theduet deployment system30. However, by utilizing

locks

47 and48, there may be a lesser likelihood of errors from accidental partial deployment of eitherprimary stent61 orsecondary stent62 at other than a desirable placement location in the patient. As shown inFIG. 1, bothfirst lock47 and thesecond lock48 are in contact withhandle46 when in their respective locked positions.

Apart from being loaded with exactly twostents60, duetstent deployment system30 may also differ from stent deployment systems of the prior art by the inclusion of aruler measurement segment49 on one of theouter sheath40 andinner catheter41. In the illustrated embodiment, aruler measurement segment49 is defined byradiopaque markers50 that are equally spaced alongaxis41.Ruler measurement segment49 andradiopaque markers50 may appear similar to features associated with AUROUS® centimeter sizing catheters with a BEACON® tip currently available from Cook Incorporated of Bloomington Indiana. For instance, gold bands spaced one centimeter apart along theruler segment49 on the outer surface ofouter sheath40 may be utilized to assist a physician in measuring various key distances within the patient's anatomy. These key distances include distances between different landmarks within the patient. These landmarks include the location where the shunt opens to the portal vein, the junction of the shunt with the hepatic vein, and the distance from that junction to the vena cava. Although longer lengths would still fall within the scope of the present disclosure, theruler measurement segment49 may be less than twelve centimeters in length, since the combined length of a primary and secondary stent in even an extremely long deployment applications will still likely be less than ten centimeters. Theruler measurement segment49 may be especially useful in measuring a distance from the patient's vena cava to a location inside the already deployedprimary stent61 in order to provide at least one centimeter overlap between the two

stents

61,62, while ensuring that the other end of thesecondary stent62 extends all the way to the vena cava in a three dimensional passage that may otherwise be difficult to measure with two dimensional imaging. Although not necessary, the distal end portion ofprimary stent62 may include ananchoring mechanism63 that is outside of sleeve covering64 and assumes a flared shape whenouter sheath40 is withdrawn sufficiently to reveal anchoringmechanism63. Nevertheless,primary stent61 need not necessarily include theoptional anchoring mechanism63.

INDUSTRIAL APPLICABILITY

The present disclosure is generally applicable to any surgical procedure where at least one but no more than two self expanding stents are needed to perform a particular procedure. The disclosure is specifically applicable to procedures in which two stents need to overlap and have a combined length that is constrained by possible uncertain patient anatomy. The present disclosure finds specific applicability to transjugular intrahepatic portosystemic shunting procedures.

Referring now in addition toFIGS. 5-8 a portion of a TIPS procedure that utilizes the duetstent deployment system30 of the present disclosure is illustrated. Prior toFIG. 5, the TIPS procedure is typical with the creation of theshunt14 throughliver tissue10 with an appropriate needle device (not shown). Thereafter, awire guide22 extends down through thepatients vena cava13 through a segment ofhepatic vein12, throughshunt14 and intoportal vein11. With thewire guide22 properly positioned, the duetstent deployment system30 is advanced over thewire guide22 into theportal vein11. In other words, the duetstent deployment system30 is maneuvered in itspre-deployment configuration42 to a position at which theprimary stent61 is positioned withinshunt14. Using appropriate imaging, the physician can confirm using radialopaque marker51, for instance, that the distal end of the duetstent deployment system30 is properly positioned in the portal vein. This initial maneuvering of duetstent deployment system30 may be performed with thedevice30 in thepre-deployment configuration42 as shown inFIG. 1. Utilizing theruler measurement segment49, while duetstent deployment system30 remains in thepre-deployment configuration42, the physician may utilize theradiopaque markers50 to size thelength17 ofshunt14, which extends from the entrance to shunt16 atportal vein11, to thejunction18 where theshunt14 connects tohepatic vein12. This information can be useful in confirming that theprimary stent61 is at least as long as thelength17 ofshunt14. Next, theouter sheath40 may be pulled back a slight distance so that anchoringmechanism63 is released. Then, the entire duetstent deployment system30 may be pulled backward until some resistance is felt when anchoringmechanism63 bears against or contacts the wall ofportal vein11, as best shown inFIG. 6. Deployment of anchoringmechanism63 may or may not require movement offirst lock47 from its locked position to its unlocked position. However, iffirst lock47 has not yet been moved to an unlocked position, after anchoringmechanism63 is positioned to bear against thewall portal vein11, thefirst lock47 may now be moved from its locked position to its unlocked position. In the event that the primary stent does not include ananchoring mechanism63, the physician may need to know precisely where the distal end of theprimary stent61 is when concealed byouter sheath40 in thepre-deployment configuration42 in order to ensure proper positioning ofprimary stent61 when deployed.

The duetstent deployment system30 is then reconfigured from thepre-deployment configuration42 as shown inFIG. 1 to the first deployment configuration of43 as shown inFIG. 3 to release theprimary stent61 inshunt14. When this occurs, theouter sheath40 is slid with respect toinner catheter31 to thefirst deployment configuration43 to releaseprimary stent61 to occupyshunt14. After releasing theprimary stent61, its positioning may be confirmed through appropriate imaging. Thereafter, the duetstent deployment system30 is repositioned to prepare for deployment of thesecondary stent62. At this point, the physician may use theruler measurement segment49 onouter sheath40 to take a second measurement in order to assess where to place thesecondary stent62. For instance, the physician may desire one end ofsecondary stent61 to the to be located at thejunction15 ofhepatic vein12 tovena cava13, and the opposite end of thesecondary stent61 to be positioned inside, in an overlapping relationship withprimary stent61. Uncertainty arises in accurately determining thedistance19 from the patient's vena cava to the junction ofshunt14 with thehepatic vein12. The secondary stent should be long enough to accommodatemeasurement distance19 plus anoverlap distance20. To be clear, theprimary stent61 overlapssecondary stent62. This overlap may occupy this distance as shown asmeasurement20 inFIG. 8. It may be desirable that a minimum overlap of one centimeter be achieved. However, a greater overlap, a lesser overlap or no overlap at all would also fall within the intended scope of the present disclosure. In order to inhibit bile from entering the bloodstream, no portion of the tissue wall that definesshunt14 should be left uncovered.

After themeasurement distance19 is noted using the radiopaque markers ofruler measurement segment49, the duetstent deployment system30 can be properly positioned with the help ofradiopaque marker51, and knowing wheresecondary stent62 is positioned oninner catheter31 with respect toradiopaque marker51. Thus, the duetstent deployment system30 may be repositioned to a position at which the distal end of thesecondary stent62 is positioned inside theprimary stent61, and a proximal end of thissecondary stent62 is positioned atjunction15 of the hepatic vein to thevena cava13. Thesecondary stent62 can now be readied for release. If included, thesecond lock48 can be moved from its locked position to its unlocked position, by removing the pin from thesystem30, and theouter sheath40 slid with respect toinner catheter31 to release and implant thesecondary stent62. In other words, the duetstent deployment system30 is reconfigured from thefirst deployment configuration43 as shown inFIG. 3 to thesecond deployment configuration44 as shown inFIG. 4 to release thesecondary stent62 to extend from the junction to the vena cava to a position insideprimary stent61. Thereafter, the duetstent deployment system30 can be withdrawn from the patient leavingwire guide22 in place. If deemed necessary, a balloon catheter (not shown) can be maneuvered alongwire guide22 and inflated within both theprimary stent61 and thesecondary stent62, especially at the

main junctions

16,18 and15 to ensure patency of the stents. When completed, the combined primary stent andsecondary stent70 may have an overlapping configuration and extend from theentrance16 to shunt14 all the way tojunction15 wherehepatic vein12 connects tovena cava13.

Those skilled in the art will appreciate that if first and

second locks

47 and48 are included, the first lock is maintained in its locked position and thesecond lock48 is maintained in its locked position while the duetstent deployment system30 is being maneuvered in thepredeployment configuration42. Likewise, thesecond lock48 may be maintained in its locked position during the step of reconfiguring the duetstent deployment system30 from thepredeployment configuration42 to thefirst deployment configuration43. In addition, thesecond lock48 may be maintained in its locked position while the duetstent deployment system30 is being repositioned prior to deployment of thesecondary stent62. Finally, thesecond lock48 may be moved to its unlocked position to enable movement of the duetstent deployment system30 from thefirst deployment configuration43 to thesecond deployment configuration44. Unlike prior art TIPS procedures, both theprimary stent61 and thesecondary stent62 are both deployed prior to withdrawal of theinner catheter31 from the patient.

By utilizing exactly twostents60 on asingle delivery system30, the physician is allowed great flexibility on the fly during the TIPS procedure. In addition, loading of the twostents60 on thesingle introducer30 allows for fewer interventions and a single access into the patient, thus saving time and reducing patient risks during the TIPS procedure. If utilized, the dual safety lock strategy (first andsecond locks47 and48) may be provided in order to prevent accidental deployment of thesecondary stent62 before adjustment has been made after theprimary stent61 has been deployed. This single access technique may reduce costs verses delivering two separate stents with two separate delivery catheters. The TIPS procedure time is also reduced with requirement of only a single access. Furthermore, hospitals may need to only inventory a small number of duetstent deployment systems30 to accommodate the wide variety of potential patients, verses inventorying multiple stent deployment systems each loaded with stents of different lengths in order to accommodate the needs of particular patients. One important aspect of the TIPS procedure to note is that some physicians place a second stent if the first stent is not long enough to extend from theportal vein11 to thevena cava13. This can be a burden because the physician may have to use an expensive stent with anchoring features, which should be unnecessary, and may be problematic for thesecondary stent62. Thus, duet stentstent deployment system30 may include exactly one stent with ananchoring mechanism63. If included, theanchoring mechanism63 may have a structure similar to the anchor feature appearing in stents available from Cook Incorporated of Bloomington Indiana.

It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.

Claims

What is claimed is:

1. A duet stent deployment system comprising:

an inner catheter;

exactly two stents mounted on a distal segment of the inner catheter, and the two stents include a primary stent and a secondary stent;

an outer sheath slidably mounted on the inner catheter, and being movable along an axis of the inner catheter from a predeployment configuration to a first deployment configuration, and then from the first deployment configuration to a second deployment configuration;

the primary and secondary stents being covered by the outer sheath in the predeployment configuration;

the primary stent being uncovered but the secondary stent being covered by the outer sheath in the first deployment configuration;

the primary and secondary stents being uncovered by the outer sheath at the second deployment configuration;

wherein the primary stent includes a sleeve covering, and the secondary stent is longer than the primary stent, and both the primary stent and the secondary stent are self-expanding stents.

2. The duet stent deployment system ofclaim 1 wherein one of the outer sheath and the inner catheter includes a ruler measurement segment defined by radiopaque markers equally spaced along the axis.

3. The duet stent deployment system ofclaim 2 wherein the ruler measurement segment is less than twelve centimeters in length.

4. The duet stent deployment system ofclaim 1 wherein the primary stent is about four centimeters long; and

the secondary stent is less than eight centimeters long.

5. The duet stent deployment system ofclaim 1 wherein the secondary stent includes a sleeve covering.

6. The duet stent deployment system ofclaim 1 wherein the primary and secondary stents have identical expanded outside diameters.

7. The duet stent deployment system ofclaim 1 including a first lock that is moveable between a locked position and an unlocked position;

a second lock that is moveable between a locked position and an unlocked position;

the duet stent deployment system being locked against movement from the predeployment configuration to the first deployment configuration when the first lock is in the locked position; and

the duet stent deployment system being locked against movement from the first deployment configuration to the second deployment configuration when the second lock is in the locked position.

8. The duet stent deployment system ofclaim 1 wherein the outer sheath includes a ruler measurement segment defined by radiopaque markers equally spaced along the axis;

the primary stent is about four centimeters long, and the secondary stent is less than eight centimeters long but longer than the primary stent.

9. The duet stent deployment system ofclaim 8 including a hub attached to a proximal end of the inner catheter;

the outer sheath being connected to a handle slidably mounted on the inner catheter;

a first lock that is moveable between a locked position in contact with the handle and an unlocked position;

a second lock that is moveable between a locked position in contact with the handle and an unlocked position;

10. The duet stent deployment system ofclaim 9 wherein the ruler measurement segment is less than twelve centimeters in length; and

the secondary stent includes a sleeve covering.

11. A method of performing a transjugular intrahepatic shunting procedure with duet stent deployment system that includes exactly two stents mounted on a distal segment of an inner catheter, and the two stents include a primary stent and a secondary stent; an outer sheath slidably mounted on the inner catheter, and being movable along an axis of the inner catheter from a predeployment configuration to a first deployment configuration, and then from the first deployment configuration to a second deployment configuration; and the primary stent includes a sleeve covering, and the secondary stent is longer than the primary stent, and both the primary stent and the secondary stent are self-expanding stents, and the method comprising the steps of:

maneuvering the duet stent deployment system in the predeployment configuration to a position at which the primary stent is positioned within a shunt extending between a hepatic vein and a portal vein;

reconfiguring the duet stent deployment system from the predeployment configuration to the first deployment configuration to release the primary stent in the shunt;

repositioning the duet deployment system to a position at which a distal end of the secondary stent is positioned inside the primary stent, and a proximal end of the secondary stent is positioned at a junction of the hepatic vein to the a vena cava; and

reconfiguring the duet stent deployment system from the first deployment configuration to the second deployment configuration to release the secondary stent to extend from the junction to a position inside the primary stent.

12. The method ofclaim 11 including a step of measuring a distance from the junction to the shunt using a ruler measurement segment of the outer sheath, which is defined by radiopaque markers equally spaced along the axis, prior to the step of reconfiguring the duet stent deployment system from the first deployment configuration to the second deployment configuration.

13. The method ofclaim 11 wherein the step of reconfiguring the duet stent deployment system from the first deployment configuration to the second deployment configuration includes implanting the secondary stent to a position at which the primary stent overlaps the secondary stent over a distance greater than about one centimeter.

14. The method ofclaim 11 including a step of measuring a length along the axis of the shunt using a ruler measurement segment of the outer sheath, which is defined by radiopaque markers equally spaced along the axis, prior to the step of reconfiguring the duet stent deployment system from the predeployment configuration to the first deployment configuration.

15. The method ofclaim 11 including a step maintaining a first lock in a locked position and a second lock in a locked position during the maneuvering step;

moving the first lock from the locked position to an unlocked position to enable movement of the duet stent deployment system from the predeployment configuration to the first deployment configuration;

maintaining the second lock in the locked position during the step of reconfiguring the duet stent deployment system from the predeployment configuration to the first deployment configuration;

maintaining the second lock in the locked position during the step of repositioning the duet stent deployment system; and

moving the second lock from the locked position to an unlocked position to enable movement of the duet stent deployment system from the first deployment configuration to the second deployment configuration.

16. The method ofclaim 11 wherein the combined primary stent and the secondary stent extend from the portal vein to the junction with the primary stent overlapping the secondary stent over a distance greater than about one centimeter.

17. The method ofclaim 11 including the steps of:

deploying an anchoring mechanism; and

withdrawing the duet stent deployment system until the anchoring mechanism contacts the portal vein at an entrance to the shunt.

18. The method ofclaim 11 wherein the primary stent and the secondary stent are released prior to withdrawing the inner catheter and the outer sheath out through the vena cava.

19. The method ofclaim 18 wherein the combined primary stent and the secondary stent extend from the portal vein to the junction with the primary stent overlapping the secondary stent over a distance greater than about one centimeter.

20. The method ofclaim 19 including a step of measuring a distance along the axis from the junction to the shunt using a ruler measurement segment of the outer sheath, which is defined by radiopaque markers equally spaced along the axis, prior to the step of reconfiguring the duet stent deployment system from the first deployment configuration to the second deployment configuration;

wherein the step of reconfiguring the duet stent deployment system from the first deployment configuration to the second deployment configuration includes implanting the secondary stent to a position at which the primary stent overlaps the secondary stent over a distance greater than about one centimeter;

measuring a length along the axis of the shunt using a ruler measurement segment of the outer sheath, which is defined by radiopaque markers equally spaced along the axis, prior to the step of reconfiguring the duet stent deployment system from the predeployment configuration to the first deployment configuration;

maintaining a first lock in a locked position and a second lock in a locked position during the maneuvering step;