Pancreas transplantation is a surgical procedure in which a diseased pancreas is replaced with a healthy pancreas that has been obtained from an immunologically compatible cadavear or living donor.
The pancreas secretes insulin that regulates glucose (blood sugar) metabolism. Patients with type I diabetes have experienced partial or complete damage to the insulin-producing beta cells of the pancreas. Consequently, they are unable to generate sufficient insulin to control blood glucose levels. Long-term uncontrolled high blood glucose levels can cause damage to every system of the body, so type I patients must inject insulin to do the work of the beta cells. Pancreas transplantation allows the body to once again make and secrete its own insulin, and establishes insulin independence for these individuals.
It is estimated that over one million people in the United States have type 1 diabetes mellitus (also called insulin-dependant diabetes or juvenile diabetes). Among these individuals, the best candidates for pancreas transplantation are typically:
A pancreas-only transplant is an uncommon procedure, with only 163 procedures occurring in the United States in 2001. More common is the combined kidney-pancreas transplant, which was performed on 885 patients the same year. An additional 305 patients received a PAK, or pancreas after kidney transplant, according to the United Network for Organ Sharing (UNOS).
Once a donor pancreas is located and tissue typing deems it compatible, the patient is contacted and prepared for surgery. Blood tests, a chest x ray , and an electrocardiogram (ECG) are performed and an intravenous (IV) line is started for fluid and medication administration. Once the transplant procedure is ready to start, general anesthesia is administered.
The surgeon makes an incision under the ribs and locates the pancreas and duodenum. The pancreas and duodenum (part of the small intestine) are removed. The new pancreas and duodenum are then connected to the patient's duodenum, and the blood vessels are sutured together to restore blood flow to the new pancreas. The patient's original pancreas is left in place.
Replacing the duodenum allows the pancreas to drain into the gastrointestinal system. The transplant can also be done creating bladder drainage. Bladder drainage makes it easier to monitor organ rejection because pancreatic secretions can be measured in the patient's urine. Once the new pancreas is in place, the abdomen and skin are sutured closed. This surgery is often done at the same time as kidney transplant surgery .
After the patient and doctor have decided on a pancreas transplant, a complete immunological study is performed to match the patient to a donor. An extensive medical history and physical examination is performed, including radiological exams, blood and urine tests, and psychological evaluation. Once the patient is approved for transplant, he or she will be placed on the United Network for Organ Sharing (UNOS) Organ Center waiting list. The timing of surgery depends on the availability of a donated living or cadaver organ.
Patients receiving a pancreas transplantation are monitored closely for organ rejection. The average hospital stay is three weeks, and it takes about six months to recover from surgery. Patients will take immunosuppressant drugs for the rest of their lives.
Diabetes and poor kidney function greatly increase the risk of complications from anesthesia during surgery. Organ rejection, excessive bleeding, and infection are other major risks associated with this surgery.
The reason simultaneous kidney-pancreas transplants and pancreas after kidney transplants are performed more frequently than pancreas only transplants is the relative risk of immunosuppressant drugs in people with diabetes. People with type I diabetes are already at risk for autoimmune problems, are more prone to infections, and have a complicated medical history that makes suppressing the immune system unadvisable.
On the other hand, diabetes is also the number one cause of chronic kidney failure, or end-stage renal disease (ESRD), which makes this group more likely to eventually require a kidney transplant for survival. In those patients with diabetes who will receive or are already receiving immunosuppressive treatment for a life-saving kidney transplant, a pancreas transplant can return their ability to self-produce insulin.
Patients with type I diabetes considering pancreas transplantation alone must weigh the risks and benefits of the procedure and decide with their doctors whether life-long treatment with immunosuppressive drugs is preferable to life-long insulin dependence.
In a successful transplant, the pancreas begins producing insulin, bringing the regulation of glucose back under control. Natural availability of insulin prevents the development of additional complications associated with diabetes, including kidney damage, vision loss, and nerve damage. Many patients report an improved quality of life.
In their 2002 Annual Report, the Organ Procurement and Transplant Network (OPTN) reported that the patient survival rate for pancreas transplant alone was 98.6% after one year and 86% after three years. Survival rates for pancreas-kidney transplant recipients were 95.1% after one year and 89.2% after three years.
Innovations in islet cell transplants, a procedure that involves transplanting a culture of the insulin-producing islet cells of a healthy pancreas to a patient with type I diabetes, have increased the frequency of this procedure. The Edmonton Protocol, a type of islet cell transplant developed in 1999 by Dr. James Shapiro at the University of Alberta (Canada), uses a unique immunosuppresant drug regimen that has dramatically improved success rates of the islet transplant procedure. As of early 2003, the Edmonton Protocol was still considered investigational in the United States, and a number of clinical trials were ongoing.
Norton, Patrice. "Pancreatic Human Islet Cells Offer Alternative to Pancreas Transplant." Family Practice News. 33 (January 2003): 14.
Reddy, K.S. et al. "Long-term survival following simultaneous kidney-pancreas transplantation versus kidney transplantation alone in patients with type 1 diabetes mellitus and renal failure." American Journal of Kidney Disease 41 (February 2003): 464–70.
American Diabetes Association. 1701 North Beauregard Street, Alexandria, VA 22311. (800) 342-2383. http://www.diabetes.org .
United Network for Organ Sharing (UNOS). 700 North 4th St., Richmond, VA 23219. (888) 894-6361. http://www.transplantliving.org .
Tish Davidson, A.M. Paula Anne Ford-Martin
A pancreas transplant is performed by a transplant surgeon in one of over 200 UNOS-approved hospitals nationwide. The patient must go through an evaluation procedure at his or her hospital of choice to get on the UNOS national waiting list and the UNOS Organ Center's UNet database.