Biliary shunts, delivery systems, methods of using the same and kits therefor

This application claims the benefit of U.S. Provisional Application No. 60/991,682, filed Nov. 30, 2007, and Application No. 61/033,368 filed Mar. 3, 2008, which application is incorporated herein by reference.

This application has related subject matter to U.S. Utility patent application Ser. No. 12/277,338, filed Nov. 25, 2008, entitled “Methods, Devices, Kits and Systems for Defunctionalizing the Cystic Duct” by Jacques Van Dam, J. Craig Milroy, and R. Matthew Ohline (identified as Attorney Docket No. 36233-701.203) and U.S. Utility patent application Ser. No. 12/277,443, filed Nov. 25, 2008, entitled, “Methods, Devices, Kits and Systems for Defunctionalizing the Gallbladder” by Jacques Van Dam, J. Craig Milroy, and R. Matthew Ohline, which applications are incorporated herein by reference.

The invention described in this patent application addresses challenges confronted in the treatment of biliary disease. Biliary disease includes conditions affecting the gallbladder, cystic duct, and common bile duct.

Bile is a greenish-brown digestive fluid produced by the liver 10 illustrated in FIG. 1, and is vital for the digestion of fatty foods. Bile is secreted by liver cells and collected by a network of ducts that converge at the common hepatic duct 12. While a small quantity of bile drains directly into the lumen of the duodenum 30 (the section of small intestine immediately downstream of the stomach), most travels through the common hepatic duct 12 and accumulates in the lumen of the gallbladder 14. Healthy gallbladders are pear-shaped sacs with a muscular wall that, on average, measure 10 cm in length and can store approximately 50 ml of fluid within its lumen. When fatty foods are ingested, the hormone cholecystokinin is released, which causes the gallbladder 14 to contract. Contraction of the gallbladder 14 forces bile to flow from the gallbladder 14, through the cystic duct 16, into the common bile duct 18, out the papilla 28, and finally into the duodenum 30 of the small intestine. Here, it mixes and reacts with the food that exits the stomach. The Sphincter of Oddi 26 controls secretions from the liver, pancreas 24, and gallbladder 14 into the duodenum 30 of the small intestine. The opening on the inside of the descending duodenum 30 after the Sphincter of Oddi 26 is called the major duodenal papilla 28 (of Vater). Together, the biliary ducts, the gallbladder 14, the cystic duct 16 and the common bile duct 18 comprise the biliary system (FIG. 1).

The pancreas 24 is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland (producing several important hormones, including insulin, glucagon, and somatostatin), as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. These enzymes help in the further breakdown of the carbohydrates, protein, and fat in the chyme. The pancreatic duct 22, or duct of Wirsung, is a duct joining the pancreas 24 to the common bile duct 18 to supply pancreatic juices which aid in digestion provided by the exocrine pancreas. The pancreatic duct 22 joins the common bile duct 18 just prior to the major duodenal papilla 28, after which both ducts perforate the medial side of the second portion of the duodenum 30 at the major duodenal papilla.

The most common problem that arises in the biliary system is the formation of gallstones, a condition called cholelithiasis. Approximately 20 million Americans have gallstones, and about 1-3% will exhibit symptoms in any given year. In the U.S., gallstones are more common among women, with 25% of women having gallstones by the age of 60 and 50% by the age of 75. Pregnancy and hormone replacement therapy increase the risk of forming gallstones. Prevalence is lower for American men: approximately 25% will develop gallstones by the age of 75. In the U.S., gallstones are responsible for the highest number of hospital admissions due to severe abdominal pain.

Gallstones 20, 20′ are most often composed of cholesterol, but may also be formed from calcium bilirubinate, in which case they are called pigment stones. They range in size from a few millimeters to several centimeters, and are irregularly shaped solids resembling pebbles. They can form in the gallbladder 14, cystic duct 16, and/or the common bile duct 18 (FIG. 2). By themselves, gallstones 20 do not necessarily result in disease states. This is the case 90% of the time. However, stones can cause infection and inflammation, a condition known as cholecystitis, which is generally the result of restricting or blocking the flow of bile from the gallbladder 14 and common bile duct 18, or the fluids secreted by the pancreas 24.

Gallbladder disease may be chronic, and patients who suffer from this may periodically experience biliary colic. Symptoms include pain in the upper right abdomen near the ribcage, nausea, and/or vomiting. The pain may resolve within an hour of onset, may prove unresponsive to over-the-counter medicines, and may not decrease with changes of position or the passage of gas. Recurrence is common, with pain often recurring at the same time of day, but with frequency of less than once per week. Fatty or large meals may cause recurrence several hours after eating, often awakening the patient at night. Patients may elect to suffer from these symptoms for very long periods of time, such as years or even decades.

Patients with chronic cholecystitis have gallstones and low-grade inflammation. Untreated, the gallbladder 14 may become scarred and stiff over time, leading to a condition called dysfunctional gallbladder. Patients who have chronic cholecystitis or dysfunctional gallbladder may experience gas, nausea, and abdominal discomfort after meals, and chronic diarrhea.

Acute cholecystitis (a surgical emergency) develops in 1-3% of those with symptomatic gallstone disease, and is due to obstruction of the common bile duct 18 or cystic duct 16 by stones or sludge. Symptoms are similar to biliary colic, though they are more severe and persistent. Pain in the upper right abdomen can be constant and severe, the intensity may increase when drawing breath, and it may last for days. Pain may radiate to the back, under the breastbone or the shoulder blades, and it may be perceived on the left side of the abdomen. In addition to nausea and vomiting, one third of patients experience fever and chills. Complications from acute cholcystitis can be serious and life threatening, and include gangrene, abscesses, perforation of the gallbladder 14 which can lead to bile peritonitis, pus in the gallbladder wall (empyema), fistulae, and gallstone ilius (when a gallstone creates a blockage in the small intestine).

When gallstones 20′ become lodged in the common bile duct 18 (FIG. 2), the condition is known as choledocholithiasis. Symptoms for this condition include pain, nausea and vomiting, and some patients develop jaundice, have dark urine and/or lighter stools, rapid heartbeat, and experience an abrupt drop in blood pressure. These symptoms can also be accompanied by fever, chills, and/or severe pain in the upper right abdomen. Complications from choledocholithiasis can also be very serious, and include infection of the common bile duct 18 (cholangitis) and inflammation of the pancreas 24 (pancreatitis).

A smaller patient population suffers from gallbladder disease that occurs in the absence of gallstones. This condition, called acalculous gallbladder disease, can also be chronic or acute. Chronic acalculous gallbladder disease, also called biliary dyskinesia, is thought to be caused by motility disorders that affect the gallbladder\'s ability to store and release bile. Acute acalculous gallbladder disease occurs in patients who suffer from other serious illnesses which can lead to inflammation of the gallbladder 14 because of a reduction in the supply of blood to the gallbladder 14 or a reduced ability to contract and empty bile into the duodenum 30.

Cancer can also develop in the gallbladder 14, though this condition is rare. Gallstones have been found in 80% of patients with gallbladder cancer. Gallbladder cancer typically develops from polyps, which are growths inside the gallbladder 14. When polyps 15 mm across or larger are observed, the gallbladder is removed as a preventive measure. Polyps smaller than 10 mm are widely accepted as posing low risk and are not generally removed. When detected early, before the cancer has spread beyond the mucosa (inner lining) of the gallbladder, the 5-year survival rate is approximately 68%. However, gallbladder cancer is not usually detected until patients are symptomatic, by which time the disease is more advanced.

The most effective treatment for biliary disease has been surgical removal of the gallbladder 14, a procedure called cholecystectomy. Surgical removal of the gallbladder 14 is indicated for patients who experience a number of less severe gallstone attacks, cholecystitis, choledocholithiasis, pancreatitis, acalculous biliary pain with evidence of impaired gallbladder 14 emptying, those at high risk for developing gallbladder cancer, and those who have previously undergone endoscopic sphincterotomy for common bile duct stones. Other treatment modalities exist and are frequently used, but gallbladder disease tends to recur in the majority of patients who forgo cholecystectomy and pursue alternatives. Removal of the gallbladder 14 is highly successful at permanently eliminating biliary disease. Cholecystectomy is one of the most commonly performed procedures on women. The gallbladder 14 is not an essential organ, and after a period of adjustment post surgery, patients tend to return to more or less normal digestive function.

Cholecystectomy can be performed either as open surgery, which requires a single larger incision in the upper right abdomen, or laparoscopic surgery, in which several small instruments are inserted through much smaller incisions in the abdomen. Approximately 80% of cholecystectomies are performed laparoscopically. The primary benefits of this minimally invasive approach are faster recovery for the patient, and a reduction in overall healthcare costs. Patients who receive laparoscopic cholecystectomy are usually released the same day. By contrast, patients receiving open cholecystectomies typically spend 5-7 days in a hospital before release. 5-10% of laparoscopic procedures convert to open procedures when difficulties arise, such as injury to major blood vessels, inadequate access, inadequate visualization, previous endoscopic sphincterotomy, and thickened gallbladder wall. Complications from cholecystectomy (open or laparoscopic) include bile duct injuries (0.1-0.5% for open, 0.3-2% with a declining trend for laparoscopic), pain, fatigue, nausea, vomiting, and infection. In up to 6% of cases, surgeons fail to identify and remove all gallstones present.

In some cases, the degree of infection and inflammation prevents patients from undergoing immediate cholecystectomy. In these cases, the gallbladder 14 must be treated with antibiotics and anti-inflammatory agents, and drained through a tube into a reservoir outside the abdomen. Placement of this tube occurs in a procedure called percutaneous cholecystostomy, in which a needle is introduced to the gallbladder 14 through the abdomen, fluid is withdrawn, and a drainage catheter is inserted. This catheter drains into an external bag which must be emptied several times a day until the tube is removed. The drainage catheter may be left in place for up to 8 weeks. In cases where no drainage catheter is inserted, the procedure is called gallbladder aspiration. Since no indwelling catheter is placed, the complication rate for gallbladder aspiration is lower than that of percutaneous cholecystostomy.