Pancreatic Transplantation

Who discovered insulin?

Banting and Best (1921)

Sir Frederick Banting of the University of Toronto was awarded the Nobel Prize for Medicine/Physiology along with John MacCleod in 1923. He initially refused to accept the award until his research assistant Charles Best's work was acknowledged, but ultimately ended up sharing his portion of the award with Best.

What are the secondary complications of diabetes mellitus?

Retinopathy
Nephropathy
Neuropathy
Enteropathy
Vasculopathy

Diabetes is the leading cause of kidney failure, blindness, nontraumatic amputation, and impotence.

Exogenous insulin can prevent the acute metabolic complications and decrease the secondary complications of diabetes, but cannot maintain a homeostatic environment.

What is the benefit of pancreatic transplantation?

It can establish normoglycemia and insulin independence and can halt the progression of secondary complications of diabetes

What is the drawback of pancreatic transplantation?

Immunosuppression

What are the methods of pancreatic transplantation?

1. PAK - pancreas after kidney transplantation
2. SPK - simultaneous pancreatic/kidney transplantation
3. PTA - pancreas transplant alone

Often PAK and SPK is performed because immunosuppression is already required for a kidney transplant.
PTA may be performed for nonuremic diabetics with a poor quality of life from ketoacidosis, labile glycemic control, or progression of secondary complications of diabetes.

When was the first pancreatic transplant performed?

1966 as an SPK. This was three years after the first kidney transplant.

What techniques are used in the drainage of the pancreas?

1. Enteric drainage (requires creatinine monitoring, for PAK or SPK)
2. Bladder drainage (requires monitoring of urine amylase)

Enteric drainage was performed in the 1970's but was superceded by ureteral, then bladder drainage. Bladder drainage became common in the 1980's, but in the 1990's enteric drainage became repopularized. Enteric drainage has been thought to be more physiologic, but requires a kidney transplant to monitor for rejection.

What are elements of the preoperative evaluation for pancreatic transplantation?

1. Assessment of degree of kidney dysfunction
2. Evaluation of secondary complications of diabetes
3. Coronary Angiography
4. Evaluation of peripheral arterial disease and iliac vessel patency
5. Rule out Malignancy
6. Rule out Infection

Why is coronary angiography often routinely performed?

Because severe diabetics are at risk for coronary arterial disease without angina.

What are the options based on kidney function?

1. PTA if Cr<2.0mg/dL with minimal proteinuria
2. PAK or SPK with moderate kidney insufficiency

What are the donor possibilities for kidney/pancreas transplants?

1. Deceased-donor SPK
2. Living-donor kidney transplant followed by deceased-donor PAK
3. SPLK: Simultaneous deceased-donor pancreas and living-donor kidney transplant
4. Living-donor SPK

What are the elements of preparation of the pancreas graft?

1. Removal of the spleen and excess duodenum
2. Ligation of the vessels at the root of the mesentery.
3. Reconstruction of the arterial system of the graft (Y-graft)

What is a pancreatic Y-graft reconstruction?

The donor SMA and splenic artery are connected using a reversed segment of donor iliac artery.

This creates a common arterial inflow channel for the pancreatic graft

What is the outflow of the pancreatic graft?

Portal vein

What are the components of the pancreatic transplant?

1. Heterotopic placement of pancreatic graft (right iliac fossa or mid-abdomen)
2. Arterial anastomosis: Y-graft to common iliac artery or distal aorta
3. Venous anastomosis: donor portal vein to recipient iliac vein (systemic) or recipient SMV (portal)
4. Drainage procedure: duodenocystostomy or duodenoenterostomy (i.e. Roux en Y)

What are complications associated with bladder drainage?

Dehydration, chronic refractory metabolic acidosis, recurrent UTI, hematuria, bladder calculi, urethritis, urinary leaks

10-20% with bladder drainage are converted to enteric drainage secondary to complications

When is bladder drainage commonly used?

With PTA (allows for rejection monitoring via urinary amylase levels), or when the kidney and pancreas are from different donors.

What are signs of rejection after pancreatic transplants?

-increased creatinine (kidney/pancreas transplants)
-decreased urinary amylase (bladder drainage)
-increased serum amylase
-increased serum glucose

What are other complications of pancreatic transplantation?

1. Infections (10%)
2. Thrombosis (6%)
3. Hemorrhage (<1% of graft loss)
4. Pancreatitis
5. Urologic complications (see bladder drainage)

What are the reported graft survival rates after pancreatic transplantation?

SPK - 90% at 1yr
PAK - 85% at 1yr
PTA - 75% at 1yr

What is a pancreatic islet cell transplant?

Cells are extracted from the islets of Langerhans of donor pancreas and injected into a diabetic patient's portal vein.

This potentially avoids a major surgical procedure, but the patient will still need long-term immunosuppression (use is still often limited to patients needing kidney transplants).

What are problems with Islet cell transplantation?

Islet cell rejection is difficult to monitor and diagnose
Complications such as hepatic abscesses, bacteremia, and portal hypertension can occur
Poor results (<5% insulin-independence at 1yr)

Late... SG

Source:
Schwartz' Principles of Surgery, 8th ed.