Patent Application
20230173239
This invention relates to lumen-apposing shunt systems for transporting fluid between two body cavities. More specifically, the present invention pertains to lumen-apposing peritoneo-vesicular shunt systems for unidirectional flow of ascitic fluid into the bladder.
A number of medical conditions could lead to chronic excess fluid collections in different body compartments, including urinary bladder distension secondary to lower urinary tract obstruction, pleural effusion, pericardiac effusion, hydrocephalus, and ascites. Among these fluid collections, ascites accumulates in the peritoneal cavity in patients with a range of pathologies, including liver disease, cancer, congestive heart failure, and kidney disease. Ascites is the leading cause of hospitalization and poor quality of life in these patients. As the volume of ascites increases, patients suffer from abdominal pain, bloating, expansion of abdominal girth and size, and shortness of breath. Appropriate clinical management of ascites is crucial to minimize complications and improve quality of life. Ascites that cannot be managed by medical therapy is called refractory ascites and is associated with poor survival and persistently worsens the quality of life (1).
The initial approach for treating ascites is dietary salt restriction and use of diuretics. However, up to 10% of patients develop tolerance and become refractory to diuretic therapy despite maximum use of diuretics. When pharmaceutical therapy alone is insufficient, interventional therapy is performed; this can be classified into two categories: (1) periodic external drainage of ascites, paracentesis, or (2) constant internal drainage or decompression of ascites to another body cavity. Paracentesis involves identifying a pocket of ascites using ultrasound imaging, inserting a largebore needle and plastic sheath through the abdominal wall into the peritoneal cavity, and removing the needle while leaving the sheath through which ascites drains. Paracentesis is an outpatient procedure that does not require sedation, and patients are promptly discharged following the procedure. Although paracentesis can be easily performed and is usually safe, it is a temporary repair and must be repeated periodically every 2-3 weeks. Repeated paracentesis is costly and may expose patients to serious complications including bleeding and infection. Paracentesis greater than 5 L of ascites is often followed by the intravenous infusion of albumin to reduce the risk of post-paracentesis circulatory dysfunction, a serious clinical condition leading to increased risk of hospitalization and mortality. Furthermore, because paracentesis is a temporary relief, patients have to endure symptoms as ascites constantly reaccumulates and expands between periodical paracenteses.
One surgical or interventional radiological approach to eliminating ascites is a peritoneo-venous shunt system (Denver shunt), which drains ascites into the superior vena cava via a subcutaneously implanted unidirectional pump (2-4). One end of the pump is connected to a multi-perforated intra-peritoneal tube, while the other end is a subcutaneous tube reaching the superior vena cava through the internal jugular vein. The valve must be manually pumped daily by the patient or caregiver to prevent fibrous particles from adhering to the catheter and causing obstruction (5). In current clinical practice, the peritoneo-venous shunt has been largely discontinued, because of serious complications including infection, coagulopathy, and venous occlusion (6). Another approach performed by interventional radiologists is transjugular intrahepatic portosystemic shunt (TIPS), which involves the creation of a shunt between portal and suprahepatic veins and the deployment of an expandable metal stent within the shunt. TIPS essentially bypasses the cirrhotic hepatic resistance and decompresses the portal hypertension, thereby reducing the recurrence of ascites (7). However, the benefits of TIPS are somewhat offset by the increased incidence of new or worsening hepatic encephalopathy following TIPS. TIPS is also not recommended in patients with severe liver disease, progressive renal failure, hepatic encephalopathy, or severe cardiopulmonary disease (1).
An alternative approach to eliminating ascites is to drain ascitic fluid into the bladder rather than into the venous blood. The first published peritoneal-urinary drainage system consisted of a squeeze-bulb and two tubes (8). The squeeze-bulb serving as a pump was implanted subcutaneously and connected to the peritoneal cavity and urinary bladder via the two tubes. External hand compression of the skin over the bulb propelled ascites into the urinary bladder. Each tube had a one-way valve to maintain unidirectional flow of the ascitic fluid from the peritoneal space to the bladder. Ascites drained to the bladder was eliminated through urination. Similar to this manual squeeze-bulb peritoneal-urinary drainage system, a more advanced system with a rechargeable battery-powered pump was developed and has become commercially available since 2011 (Alfapump system, Sequana Medical AG, Zurich, Switzerland) (U.S. Pat. No. US9149613B2) (9). The Alfapump system consists of a subcutaneously implanted battery-powered pump connected to the peritoneal cavity and urinary bladder via two tubes. The pump allows ascites to continuously drain from the peritoneal cavity into the urinary bladder. The system has pressure-monitoring sensors and is programmable to specify volume and time of infusion. The pump and tubes are surgically placed under general anesthesia. The Alfapump system was evaluated in recent clinical trials and found to be effective for reducing the need for paracentesis and improving quality of life in patients with refractive ascites (10, 11). However, there remained a number of adverse events related to the surgical procedure and the Alfapump system, requiring careful patient selection and postoperative monitoring to balance the benefit against the invasiveness and frequent complications of the system (1).
A variation of the peritoneal-urinary drainage system is to directly shunt ascites from the peritoneum to the bladder without a pump that connects and bypasses the two body compartments. A few devices were described in recently published patents (US8394048, US20140012180A1, WO 2018/071373 Al) (12, 13). The proposed devices included a one-way valve mechanism to enforce unidirectional flow of fluid and prevent reflux of urine. The devices were secured in the bladder wall by different types of anchorage mechanisms, such as a flange or plug that seats on and braces both edges of the bladder walls containing the shunt opening. Compared to these bracket-like anchorage mechanisms that directly lock onto the bladder wall, in our approach we use a lumen-apposing retention means that does not directly brace the bladder wall but rather peripherally apposes to the surface of the bladder wall. Our lumen-apposing retention system is based on the consideration that the bladder wall is not a fixed rigid structure, but a muscle that constantly and dynamically varies in shape and size as urine accumulates and dissipates from the bladder.
An additional important consideration in designing a shunt device is how to access body cavities and implant the shunt device across the body cavities. A device is designed to be implanted either surgically by a surgeon through an opening made in the abdominal cavity or transurethrally without surgery by means of a highly sophisticated transurethral cystoscopic system that may be able to introduce the bladder wall anchorage device. However, the non-surgical transurethral implantation of the shunt devices, particularly regarding how to implant bulky bladder anchorage components, remains a major practical and technical challenge.
As patients with ascites are often in debilitated health conditions and have limited tolerance in extensive surgical procedures, it is highly desirable to implement a safe, non-invasive, and efficient treatment method without requiring a prolonged risky surgical operation. Therefore, it is essential to develop a device that is highly effective in the treatment of ascites and is relatively easily implantable using a minimally invasive interventional radiological or surgical procedure. Additional practical features of a device would include simplicity in operation (drainage of ascites on the basis of gravity and/or contraction of patient’s voluntary muscles without requiring complex programming or pumping system) and the easy removal of the device when clinically indicated.
In the first aspect of the present invention, a shunt device transporting fluid between two body cavities is provided which comprises:
The retention means may contain fiducial markers including radio-opaque fiducial markers for tracking the location and position of the retention means.
In one embodiment, the retention means may be double self-expandable wheels.
Here, this type of the shunt device is called the self-expandable double-wheel shunt device.
In another embodiment, the retention means may be double inflatable balloons, and the shunt device further comprises:
Here, this type of the shunt device is called the inflatable double-balloon shunt device.
Wherein, the self-expandable wheels may be composed of biocompatible polymer or silicon.
Wherein, the hollow drainage tube may comprise a peritoneal portion located in the peritoneal cavity and a bladder portion located in the bladder.
Wherein, the peritoneal portion of the hollow drainage tube may comprise one or more holes to enhance the drainage of ascites.
Depending on clinical needs, a shunt device is applicable to transporting various type of body fluid between two body cavities. For ascites, the first body cavity is the peritoneal space while the second body cavity is the bladder. For fetal urinary fluid secondary to lower urinary tract obstruction, the first body cavity is the fetal bladder while the second body cavity is the maternal amniotic sack. For pleural effusion, the first body cavity is the pleural space while the second body cavity is the peritoneal space. For pericardiac effusion, the first body cavity is the pericardiac space while the second body cavity is the pleural space. For a pancreatic cystic fluid collection, the first body cavity is a pancreatic cyst while the second body cavity is the stomach. For a visceral fluid collection, the first body cavity is a visceral fluid collection pocket while the second body cavity is the gastric or intestinal or bladder lumen. For the purpose of draining a body fluid collection to outside of the body, the first body cavity is a body fluid collection pocket while the second body cavity is an external drainage bag outside of the body. In some clinical needs including a continued washout of a body cavity or enteric nutritional support rather than drainage, the aforementioned first body and second cavities may be switched with reversed fluid flow direction.
The shunt device can be implanted in a body of patient, via a transurethral, transvesicular, or transabdominal approach, depending on the indication of clinical applications and accessibility of the device.
In the second aspect of the present invention, a combined assembly for implanting a shunt device is provided.
In one embodiment, the shunt device of the combined assembly is the self-expandable double-wheel shunt device, and the combined assembly for implanting the self-expandable double-wheel shunt device comprises:
In one embodiment, the shunt device of the combined assembly is the inflatable double-balloon shunt device, and the combined assembly for implanting the inflatable double-balloon shunt device comprises:
The combined assembly may further comprise a guide wire which is introduced through or laterally along the hollow lumen of the trocar to serve as a cannulation track for a shunt device to move across the body cavities.
Wherein, the guide catheter may contain fiducial markers including radio-opaque fiducial markers to track the location and position of the guide catheter.
In the third aspect of the present invention, a method to implant a peritoneo-vesicular shunt device from the combined assembly via urethra is provided.
In one embodiment, the shunt device of the combined assembly is the self-expandable double-wheel shunt device, and the method to implant the self-expandable double-wheel peritoneo-vesicular shunt device from the combined assembly comprises:
In another embodiment, the shunt device of the combined assembly is the inflatable double-balloon peritoneo-vesicular shunt device, and the method to implant the inflatable double-balloon peritoneo-vesicular shunt device from the combined assembly comprises:
The method to implant a peritoneo-vesicular shunt device from the combined assembly via urethra may further comprise:
In the fourth aspect of the present invention, a method to remove the implanted shunt device is provided.
In one embodiment, the shunt device of the combined assembly is the self-expandable double-wheel shunt device, and the method to remove the implanted double-wheel shunt device comprises:
In another embodiment, the shunt device of the combined assembly is the inflatable double-balloon shunt device, and the method to remove the implanted double-balloon shunt device comprises:
Some embodiments of the present invention are peritoneo-vesicular shunt devices that are designed to be implanted through the urethra and retained across the bladder wall to permit the drainage of ascites into the bladder.
The inferior aspect of the peritoneum abuts the urinary bladder. Ascites accumulates in the peritoneal cavity. When a shunt is implanted between the peritoneal cavity and bladder, ascites drains via the shunt into the bladder and is subsequently eliminated by urination. The flow of ascites is facilitated by the force of gravity or increased intra-abdominal pressure due to increased volume of ascites or patient’s tensing of abdominal muscles. No external mechanical pump is necessary to move ascites from the peritoneal cavity to bladder.
The shunt device is placed at a location where the peritoneum and bladder wall anatomically juxtapose to promptly facilitate the creation of a peritoneo-vesicular shunt.
The shunt device is configured in two types: a self-expandable double-wheel type and an inflatable double-balloon type.
The self-expandable double-wheel shunt device consists of a hollow, cylindrical column with double wheels to provide secure retention at the peritoneum and bladder wall interface. After the placement of the self-expandable double-wheel shunt device, the double wheels that envelope transversely both ends of the shunt device are self-expanded, with one wheel within the peritoneal cavity and the other within the bladder lumen, thereby retaining the device across the bladder wall as a peritoneo-vesicular shunt.
The inflatable double-balloon shunt device consists of a hollow, cylindrical column with double balloons to provide secure retention at the peritoneum and bladder wall interface. After the placement of the device, double balloons enveloping the transverse mid-body of the device are inflated, with one balloon within the peritoneal cavity and the other within the bladder lumen, thereby retaining the device across the bladder wall as a peritoneo-vesicular shunt device.
In both types of the shunt device, the proximal uptake portion of the device extends into the peritoneal cavity to be in communication with ascites, while the distal portion of the device extends into the bladder. The shunt device contains a one-way valve mechanism (e.g., duckbill valves) to provide unidirectional flow of the fluid from the peritoneal cavity to the bladder and to prevent reflux of urine into the peritoneal cavity.
The peritoneo-vesicular shunt devices described in detail in the present embodiment are for implantation through a transurethral route without requiring cutting skin or surgery. However, the devices may be implanted using a transvesicular or transabdominal route with or without guidance of various imaging systems including ultrasound, CT, MRI, fluoroscopy, cystoscopy, and laparoscopy.
The transurethral implantation of the device is performed by a series of catheter-based operations. The first step is an insertion of a semi-rigid guide catheter through the urethra into the bladder. The intravesicular tip of the guide catheter is placed and adjusted to abut the bladder wall at a target of the shunt device implantation that can be selected with guidance of imaging. The second step is an introduction of a trocar through the lumen of the guide catheter to puncture the target bladder wall to create a shunt pathway. The third step is pushing and advancing the shunt device using a pusher catheter through the guide catheter such that the peritoneal portion of the shunt device is uncovered and released out of the guide catheter into the peritoneal space.
In the self-expandable double-wheel shunt device, the freed peritoneal wheel expands by itself to be retained in the peritoneal space. After the shunt device is placed appropriately across the peritoneum and bladder wall interface, the fourth step is a slight withdrawal of the assembly of the guide catheter and shunt device to place the tip of the guide catheter within the bladder while maintaining the expanded peritoneal wheel to appose to the bladder wall. The fifth step is a partial pullback of the guide catheter while keeping the pusher catheter stationary to expose the bladder portion of the shunt device within the bladder.
In the double-wheel shunt device, the freed bladder wheel expands by itself to be retained in the bladder.
For the inflatable double-balloon shunt device, an additional step is required to inflate the double balloons of the shunt device to secure the device across the bladder wall. The inflation of the balloons is achieved by delivery of fluid or air via a long, small-caliber balloon inflation feeding tube which extends from outside of the patient to the entrance of the balloon inflation lumen of the shunt device. The balloon inflation feeding tube runs parallel to the course of the pusher catheter within the guide catheter. The entrance of the balloon inflation lumen of the shunt device is obstructed by a one-way balloon valve. The balloon inflation feeding tube is initially connected and inserted through the one-way balloon valve into the balloon inflation lumen. After the inflation of the balloons is achieved by infusion of air or fluid via the balloon inflation feeding tube, the balloon inflation tube is pulled away and removed. Once the shunt device is securely retained by either the expanded double-wheels or the inflated double-balloons, the guide catheter and pusher catheter are removed from the shunt device to complete the implantation process.
When it is desired to remove an implanted double-wheel shunt device, the shunt device in the bladder side is directly pulled and removed by using a grasping forceps via cystoscopy. For an implanted double-balloon shunt device, a biopsy or snipping tool via cystoscopy is introduced to snip and deflate the bladder balloon that sustains the shunt device at the bladder wall. With the deflation of both balloons, the shunt device is freed and removed by using a grasping forceps of a cystoscope.
The self-expandable double-wheel shunt device 101 includes a pair of expanded wheels spaced apart such that the peritoneal wheel 107 is deployed within the peritoneal cavity 104 while the bladder wheel 108 is located within the bladder 105. The expanded wheels allow the shunt device to be retained across the bladder wall.
The inflatable double-balloon shunt device 102 contains a hollow tubular structure 109 whose structure and function are the same as the aforementioned tubular structure 106 to form a passage of ascites from the peritoneal cavity to the bladder. The inflatable double-balloon shunt device 102 includes a pair of inflatable balloons spaced apart such that the peritoneal balloon 110 is deployed within the peritoneal cavity 104 while the bladder balloon 111 deployed within the bladder 105. The inflated balloons secure the shunt device to be retained across the bladder wall.
The hollow tube 203 contains side holes 206 to enhance the drainage of ascites. One-way valve (e.g., duckbill valve) 207 is located in the lumen of the tube 203 to allow unidirectional flow of ascites from the peritoneal cavity to the bladder and to prevent reflux of urine into the peritoneal cavity. One-way valve 207 is designed and configured to appropriately open and close in response to pressure gradients between the peritoneal cavity and bladder. Increased peritoneal pressure due to accumulated ascites or contraction of abdominal muscles will provide force to open the valves to drain ascites into the bladder. Valves remain closed without a positive pressure gradient exerted from the peritoneum to the bladder.
During or after the implantation of a shunt device, it is informative to track and monitor the location and configuration state of the shunt device in the body cavities. For this purpose, the hollow tube 203 is partially or entirely coated with barium sulfate. In addition, fiducial markers 208 are embedded in the shunt device. Fiducial markers made of radio-opaque materials including barium sulfate or metal can be detected under fluoroscopy or CT. Monitoring changes in the position of the hollow tube and fiducial markers in the wheels facilitate the evaluation of folded or expanded configuration of the shunt device.
One-way drainage valve (e.g., duckbill valve) 507 is located in the central lumen 503 to allow unidirectional flow of ascites from the peritoneal cavity to the bladder and to prevent reflux of urine into the peritoneal cavity. One-way valve 507 is designed and configured to appropriately open and close in response to pressure gradients between the peritoneal cavity and bladder. Increased peritoneal pressure due to accumulated ascites or contraction of abdominal muscles will provide force to open the valves to drain ascites into the bladder. Valves remain closed without a positive pressure gradient exerted from the peritoneum to the bladder.
Inflation and deflation of the balloons 505 and 506 is accomplished through the balloon lumen 504. The entrance of the balloon lumen 504 contains a one-way balloon valve (e.g., duckbill valve or elastic plug valve) 508 which keeps the balloon lumen 504 closed unless forcefully pushed apart to open.
The peritoneal balloon 506 envelops the peritoneal portion of the shunt device within the peritoneal cavity and secures the upstream drainage position of the shunt device. The bladder balloon 505 envelopes the bladder portion of the shunt device spaced apart from the peritoneal balloon 506 to ensure that the shunt device between the two balloons is lodged at the bladder wall. Both balloons are in communication with the common balloon lumen 504 for inflation and deflation of the balloons.
More than one shunt device can be placed at different locations of the bladder wall to enhance the efficiency of draining ascites, when clinically indicated. When it is desired to remove an implanted double-wheel shunt device, the shunt device in the bladder is directly pulled and removed by using a grasping forceps via cystoscopy. As an illustration,
Although the description of the present invention illustrates mainly the transurethral approach for the implantation of a shunt device, alternative approaches such as the transvesicular and transabdominal insertion approaches are available to access and implant the shunt device depending on clinical indications. For the transvesicular approach, a subcutaneous incision is made at a suitable site on the anterior lower abdomen over the expected suprapubic bladder. A needle is inserted through the abdominal and bladder wall into the bladder lumen. A flexible guide wire is introduced through the bore of the needle which is then removed while the guide wire remains in place. A dilator and introducer sheath are placed over the guide wire and the small needle hole is dilated to a sufficient caliber to accommodate a guide catheter shown in
Furthermore, although the description of the present invention focuses mainly on the peritoneo-vesicular shunt device, the shunt device is applicable to transporting various type of body fluid between two body cavities.
For example, for fetal urinary fluid secondary to lower urinary tract obstruction, the first body cavity is the fetal bladder while the second body cavity is the maternal amniotic sack. For pleural effusion, the first body cavity is the pleural space while the second body cavity is the peritoneal space. For pericardiac effusion, the first body cavity is the pericardiac space while the second body cavity is the pleural space. For a pancreatic cystic fluid collection, the first body cavity is a pancreatic cyst while the second body cavity is the stomach. For a visceral fluid collection, the first body cavity is a visceral fluid collection pocket while the second body cavity is the gastric or intestinal or bladder lumen. For the purpose of draining a body fluid collection to outside of the body, the first body cavity is a body fluid collection pocket while the second body cavity is an external drainage bag outside of the body. In some clinical needs including a continued washout of a body cavity or enteric nutritional support rather than drainage, the aforementioned first body and second cavities may be switched with reversed fluid flow direction.
While the invention has been described with reference to a preferred embodiment, it is to be understood that the foregoing description is merely illustrative, and variations in form, construction, and arrangement may be carried out in other ways without departing from the true spirit and scope of the invention and the following claims.
