Multi-needle transjugular intrahepatic portosystemic shunt device

1. Field of the Invention

The present invention relates to an apparatus and method for quickly locating a liver portal vein to establish a shunt through a human liver between the portal vein and the hepatic vein, and more particularly to a multi-needle Transjugular Intrahepatic Portosystemic Shunt (“TIPS”) device and a method for establishing a TIPS using the multi-needle TIPS device.

2. Description of Related Art

The human liver has many functions essential to life including breaking down fats, glucose metabolism/storage, urea production, amino acid synthesis, toxin filtration, storage of vitamins and minerals, and cholesterol metabolism. On average, the healthy liver receives around 70-75% of its blood supply from the portal vein and 25-30% from the hepatic artery. Blood leaves the liver through the hepatic veins which communicate with the inferior vena cava just below the heart.

Liver cirrhosis is a term that refers to irreparable damage to the liver where the hepatic parenchyma is progressively replaced with scar tissue. With time, this can progress to complete liver failure. There are numerous causes of liver cirrhosis, but common causes include alcohol abuse, hepatitis, non-alcoholic steatohepatitis (NASH), toxin/drug exposure, and various inherited and autoimmune conditions. As the liver becomes cirrhotic, the normal blood flow patterns become altered. Specifically, the pressure within the portal veins increases causing the blood that would normally flow to the liver to “back-up.” Over time the portal blood that normally flows towards the liver (hepatopedal) can reverse and flow away from the liver (hepatofugal). As the postal vein pressures rise, the blood finds alternative routes to return to the heart. This typically occurs in the form of variceal vessels that are particularly prone to hemorrhage with potentially fatal consequences.

In addition, the increased portal vein pressures observed with cirrhosis raises capillary hydrostatic pressures within the splanchnic vascular bed of the viscera. As the hydrostatic pressure rises, a transudative fluid collection, known as ascites, can form in the patient's abdomen. Although typically this is initially managed with medical therapy, the amount of fluid can become quite large and refractory to medical therapy.

Originally described by Rosch et al. in 1969, the TIPS procedure creates a shunt between the portal veins and the hepatic veins allowing blood to bypass the cirrhotic hepatic parenchyma that is responsible for the elevated portal vein pressures. In so doing, the TIPS procedure decreases portal pressure and is indicated in the management of variceal bleeding refractory to medical therapy, refractory ascites, and refractory hepatic hydrothorax (fluid surrounding the lungs secondary to liver failure).

There are several commercially available kits for the TIPS procedure. The TIPS procedure is performed under general anesthesia by accessing the patient's right internal jugular vein and advancing a catheter through the superior vena cava, heart, and inferior vena cava to the right hepatic vein. Once catheter access to the right hepatic vein is made, a larger sheath is then placed into the right hepatic vein. Through this sheath a large needle (typically 16 Gauge) is pushed through the wall of the hepatic vein into the parenchyma anteromedially in the expected direction of the right portal vein. After the needle has been advanced, a syringe is attached to the back of the needle and the needle is slowly withdrawn. When blood is aspirated, a small injection of contrast is made into the needle to confirm access into the right portal vein. Wire access through the needle into the right portal vein and main portal vein is then made. Over this wire, a tract is balloon dilated and a covered stent is placed thus forming the shunt.

Despite the use of preprocedural imaging as well as intraprocedural wedge portography, access to the portal vein can often prove difficult requiring numerous passes of the needle before access is obtained. The passage of the needle through the liver is associated with complications including intraperitoneal bleeding (frequency 1-13%), hemobilia (frequency 1-4%), and fistula formation (frequency <1%). Equally important, the difficulty of portal vein access extends procedure time with the increased use of hospital resources/expenses and the added risk to the patient of prolonged anesthesia. Therefore, there is a need for a TIPS device and method that can obtain access to the portal vein more safely and rapidly.

The present invention relates to a device that is designed to improve the safety and efficacy of catheterization of the portal vein during a TIPS procedure and a method for using the device. This is accomplished by simultaneously advancing multiple smaller needles through the liver parenchyma from the distal end of the TIPS needle of the device. In so doing, the device allows sampling from a significantly larger volume of the liver with each pass thereby facilitating the rapid catheterization of the portal vein from the hepatic vein.

The proposed device is superior to the prior art because it employs a plurality of needles, each smaller than the needle used in a typical TIPS procedure, that are simultaneously advanced into the hepatic parenchyma. The needles will spread apart in area progressively as they are manually advanced into the hepatic parenchyma with the tips forming a square or polygonal pattern accordingly. The use of multiple needles multiplies the likelihood of catheterizing the portal vasculature and reduces the time in which the this is done compared to passage of a single needle as is typically employed in a TIPS procedure.

In addition, the needles used in this device are considerably smaller than the 16 Gauge needle used in a typical TIPS procedure. The present invention uses needles as small as 21 or 23 Gauge. The use of smaller needles is less traumatic to the vascular liver. It therefore will decrease the likelihood of potentially fatal complications, including hemorrhage, hemobilia, fistula creation, and injury to adjacent organs. The larger needle that houses these smaller needles will only be advanced a very short distance into the hepatic parenchyma and therefore is much less invasive.

Consequently, the device will result in considerable cost savings and improved safety by shortening the length of time of the procedure. The decrease in procedural time is significant as it lowers the rate of complications related to the administration of general anesthesia. Moreover, the decrease in procedural time offers cost savings benefits to the healthcare system.

In another embodiment, the device employs 6 smaller needles that extend from the distal end of a TIPS needle.

In yet another embodiment, the device employs 8 smaller needles that extend from the distal end of a TIPS needle.

In yet still another embodiment, the device employs only one sheath in which the TIPS needle passes through.

It is an object of the present invention to provide a multi-needled TIPS device that can obtain access to the portal vein from the hepatic vein more safely and rapidly.

It is another object of the present invention to provide a method for using the multi-needled TIPS device to reduce the time necessary to establish a shunt.

In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.

FIG. 1 is a drawing to illustrate a human liver, the hepatic vein, and the portal vein.

FIG. 2 is a side cross-sectional view in elevation of the present invention in a retracted state.

FIG. 3 is a side cross-sectional view in elevation of the present invention in an extended state.

FIG. 4 is a side elevational view partially cut away of an outer sheath built in accordance with the present invention.

FIG. 5 is a side elevational view partially cut away of an inner sheath built in accordance with the present invention.

FIG. 6 is a side elevational view of a TIPS needle in a retracted state built in accordance with the present invention.

FIG. 7 is a side view of a TIPS needle with four engaging needles in an extended state and the tip of the TIPS needle in phantom built in accordance with the present invention.

FIG. 8 is a perspective view partially cutaway of the distal end of a TIPS needle built in accordance with the present invention.

FIG. 9 is a side elevational view of the distal end of a TIPS needle with a needle stylets in partial phantom built in accordance with the present invention.

FIG. 10 is a side elevational view of engaging needles and a common needle hub built in accordance with the present invention.

FIG. 11 is a side elevational view of stylets and a common stylet hub built in accordance with the present invention.

FIG. 12 is a side elevational view in cross section of an aspirating syringe built in accordance with the present invention.

A multi-needle TIPS device and a method for using the multi-needle TIPS device, in accordance with the present invention, are described with initial reference to FIG. 1 . The device and method described herein is desirable for locating quickly the proper portal vein for establishing a shunt 103 through a human liver 100 , connecting the right hepatic vein 101 to the right portal vein 102 .

Referring now to FIGS. 2 , 3 , 4 , 5 , 6 , and 7 , the device 200 and its primary components are depicted in isolation and in a retracted and extended state. FIG. 2 shows the device 200 in the retracted state, which is a non-engaging, default state. An outer sheath 201 is the primary exterior component of the device 200 . The outer sheath comes with an inner dilator [is dilator shown in drawings?] to allow introduction over a wire into the right hepatic vein. The outer sheath 201 is a ten (10) French sheath which is made of a semi-rigid material. In FIG. 4 , the outer sheath 201 has a shaft that measures between 35 and 40 cm in length and an outer hub 203 with an outer side port 202 at its proximal end that is designed to allow flushing of the outer sheath 201 .

In FIG. 5 , the lumen of the outer sheath 201 accommodates an inner sheath 204 . The inner sheath 204 is an eight (8) French sheath which is made of a semi-rigid material. The shaft of the inner sheath measures 45 cm in length has a tapered end 207 . The inner sheath 204 also has an inner hub 205 and inner side port 206 at its proximal end to allow for flushing of the inner sheath 204 . The shaft of the inner sheath 204 also has a braided metallic wall to allow passage of an 8 French needle without damage to the inner sheath 204 .

The lumen of the inner sheath 204 accommodates a TIPS needle 208 , which in total measures 50 cm in length, including a curved portion 211 of 7 cm at the TIPS needle's distal end 214 . The TIPS needle is an eight (8) French needle made of a semi-rigid material. The curved portion 211 has a 30 degree curve. At distal end of the TIPS needle 208 is a TIPS needle tip 209 (See FIG. 6 ). Near the distal end of the TIPS needle 208 , before the TIPS needle tip 209 , there are four needle holes 212 designed to allow smaller needles to pass through. The TIPS needle also has a TIPS needle hub 213 at the proximal end 215 of the TIPS needle.

Referring back to FIG. 3 shows the device 200 depicted in the extended state. The extended state is the engaging state and is defined by the extension of four (4) engaging needles 216 from the distal end 214 of the TIPS needle 204 . The engaging needles 216 are each twenty-three (23) gauge needles made from a semi-rigid material and each has a preformed gentle curve in its tip. The engaging needles 216 pass through the TIPS needle lumen 210 , with each engaging needle 216 extending from one of the four needle holes 212 of the TIPS needle 208 . Inside the TIPS needle lumen 210 , the engaging needles 216 are separated by thin horizontal and vertical septations 218 in the TIPS needle lumen 208 . As seen in FIG. 7 , while extending, the engaging needles 216 progressively spread apart in a square pattern. When fully extended, the engaging needles 216 lie in a square pattern with 2-3 cm between the needles.

Referring now to FIGS. 8 , 9 , 10 , and 11 , the primary components that comprise the interior of the device are shown. FIG. 8 shows the proximal end 215 of the TIPS needle 208 . At the proximal end 215 of the TIPS needle 208 is the TIPS needle hub 213 . The TIPS needle hub 213 serves as the base of the TIPS needle 208 and houses the hub adapter 217 . As a result of the horizontal and vertical sepations 218 in the TIPS needle lumen 208 , the TIPS needle lumen 208 contains four distinct chambers, each of which can accommodate one engaging needle 216 . The engaging needles are each attached to a common needle hub 223 , which allows the engaging needles to be advanced and retracted together. To assure that proper pattern of the engaging needles 216 when they are extended from the TIPS needle 208 , each engaging needle 216 has a specific target chamber within the TIPS needle 208 . If the engaging needles 216 are inserted into the proper chamber, then once the engaging needles 216 are completely advanced into the TIPS needle 208 , the common needle hub 223 will engage the hub adapter 217 .

Stylets 221 , are used to fill the engaging needle lumen 219 and provide additional rigidity to the engaging needles 216 when they are advanced into the engaging needle lumen 219 . The stylets 221 are of twenty-three 23 gauge size, made from a semi-rigid material, and are all attached to a common stylet hub 222 . In addition, the stylets 221 have the same preformed curve as the engaging needles 216 . The stylets 221 are utilized by insertion first through a sliding cover 220 , then through the common needle hub 223 , and finally through the engaging needle lumen 219 .

Referring now to FIG. 12 , a specially designed syringe 224 is shown. The syringe 224 is a sixty (60) cc syringe that is designed to engage the common needle hub 223 ( FIG. 9 ) and provide aspiration through the engaging needle lumen 219 . The syringe has an engaging tip 225 with four independent syringe chambers 227 , where each chamber 227 corresponds to one of the four engaging needle lumen 219 ( FIG. 8 ). Along with an opening for each syringe chamber 227 , the engaging tip 225 also houses a syringe adapter 228 that fits the common needle hub 223 . When syringe 224 is engaged to the common needle hub 223 and the plunger 226 of the syringe 224 is pulled, aspiration is provided through each of the engaging needle lumen 219 .

The operation of the device begins with the access of the right hepatic vein 101 ( FIG. 1 ) from the right jugular vein. Under ultrasound guidance, a twenty-one (21) Gauge needle will be used to access the right jugular vein. After obtaining access, a 0.018″ wire is advanced through the lumen of the twenty-one (21) Gauge needle and its position confirmed in the superior vena cava with fluoroscopy. A transitional dilator is used to upsize the wire. Catheterization of the right hepatic vein 101 is then performed. Wedge hepatic pressures and portography are performed as needed. The outer sheath 201 and inner dilator are advanced over the wire into the right hepatic vein 101 . The inner dilator is then removed and the outer side port 202 is connected to a heparinized saline flush.

Next, the TIPS needle 208 is partially inserted into the inner hub 205 and then the inner sheath 204 , so as not to extend the TIPS needle tip 209 beyond the distal end of the inner sheath 204 . The assembled apparatus of the TIPS needle 208 and the inner sheath 204 is then inserted into the outer hub 203 and then the outer sheath 201 and extended to the wall of the right hepatic vein 101 . Once placed, the inner side port 206 can be connected to a heparinized saline flush as needed.

The engaging needles 216 with their stylets 221 seated are then advanced into the TIPS needle hub 213 , but the tips of the engaging needles 216 are not extended through the holes near the end of the TIPS needle 208 . At this point, the assembled device will be as shown in FIG. 2 . Next, the TIPS needle 208 is slowly advanced a short distance into the hepatic parenchyma anteromedially in the expected direction of the right portal vein 102 . The distance that the TIPS needle is advanced into the hepatic parenchyma will likely be around 1 cm, unlike the usual distance of approximately 5 cm that is employed with a typical TIPS apparatus.

Once the TIPS needle 208 is seated in proper position, the engaging needles 216 with their inner stylets 221 are slowly advanced into the hepatic parenchyma. At this point, the assembled device will be as shown in FIG. 3 . The engaging needles 216 are advanced approximately 3-6 cm. As the engaging needles 216 are advanced through the needle holes 212 near the end of the TIPS needle 208 into the hepatic parenchyma they will gradually spread apart in a square shape, as depicted in FIG. 7 . When fully extended, the tips of the engaging needles will lie in a square pattern with 2-3 cm between the needles. Since the needles progressively spread with further advancement, extending the engaging needles 216 a shorter distance will result in the needle tips lying closer to one another in a smaller square pattern.

The stylets 221 are removed from the engaging needle lumen 219 by pulling on the common stylet hub 222 . As the stylets 221 are withdrawn from the engaging needles 216 , their tips are covered by the needle cover 220 . This needle cover 220 is designed to prevent a needle injury to the operator and to keep the stylet tips together when disengaged from the engaging needles 216 . The stylets 221 with their tips covered by the needle cover 220 can then be placed to the side.

With the stylets removed, the syringe 224 is then attached to the common needle hub 223 with each syringe chamber 227 corresponding to one engaging needle lumen 219 . The operator then pulls on the plunger 226 to cause an aspirating force through the engaging needle lumen 219 and the tips of the engaging needles 216 . The engaging needles 219 are then slowly retracted through the hepatic parenchyma while being aspirated with the syringe 224 by pulling on the syringe 224 together with the common needle hub 223 . As the operator retracts the engaging needles 216 , the individual syringe chambers 227 are carefully inspected for the presence of portal blood. If blood is not aspirated, the engaging needles 216 can be withdrawn into the TIPS needle 208 and the stylets 221 are replaced into the engaging needle 216 . The engaging needles 216 are then advanced in a different direction and the process is repeated until aspiration of blood is successful.

When blood is aspirated into one of these syringe chambers 227 , retraction of the engaging needles 216 is immediately stopped. The syringe chamber 227 and corresponding engaging needle lumen 219 containing blood are noted. The syringe 224 is then removed from the common needle hub 223 . A small injection of contrast is then made into the engaging needle lumen 219 from which blood was aspirated. This is performed under fluoroscopy to confirm access into the right portal vein 102 . Next, under fluoroscopy, a 0.018″ wire is advanced into the appropriate engaging needle lumen 219 that had aspirated blood. This wire is advanced well into the right portal vein 102 and then into the main portal vein, splenic vein, or superior mesenteric vein as is necessary to obtain adequate purchase for further intervention.

Once adequate purchase is obtained, the TIPS needle 208 and the attached engaging needles 216 are pulled back as a unit together over the wire. Serial dilatation is then performed over the 0.018″ wire and the 0.018″ wire is upsized for a larger 0.035″ wire. Over the 0.035″ wire balloon angioplasty and placement of a covered stent can be performed as is done with a typical TIPS procedure. The procedure is completed with a repeat portogram and measurement of portal pressures as well as potential embolization of varices as required.

The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made there from within the scope of the invention and that obvious modifications will occur to a person skilled in the art.