Transplant Pancreatectomy

David Shaffer

DEFINITION

Transplant pancreatectomy is defined as excision or removal of previously transplanted pancreatic allograft.
The most common indication for transplant pancreatectomy is early pancreas allograft failure with hyperglycemia and return to insulin dependence.
The most common cause of early graft failure requiring transplant pancreatectomy is graft thrombosis, either arterial or venous.
- Thrombosis has been reported to occur in up to 10% of pancreas transplants.
- Case reports of successful salvage of early thrombosis, usually partial thrombosis, have been published; but usually, by the time the diagnosis is made and patient is reexplored, the pancreas is necrotic and requires complete explantation.
Other indications for transplant pancreatectomy include the following:
- Primary nonfunction
- Other technical complications, including enteric leak with associated peritonitis and systemic sepsis
- Acute rejection, cellular or antibody-mediated; unresponsive to antirejection therapy
- Refractory transplant pancreatitis
Late allograft failure (i.e., 1 or more years posttransplant) with hyperglycemia and resumption of insulin dependence, usually due to chronic rejection with graft fibrosis and atrophy, does not require transplant pancreatectomy in the otherwise asymptomatic patient.

DIFFERENTIAL DIAGNOSIS

The differential diagnosis of early pancreas allograft dysfunction with hyperglycemia and insulin dependence includes the following:
- Thrombosis, arterial or venous
- Delayed graft function
- Acute pancreatitis
  - Ischemia or reperfusion
  - Reflux, especially for bladder-drained pancreas transplants
  - Viral infection, especially cytomegalovirus (CMV)
- Acute rejection
- Enteric leak with sepsis
- Drug toxicity with glucose intolerance secondary to steroids and/or calcineurin inhibitors
Early allograft failure usually mandates transplant pancreatectomy regardless of etiology in order to
- Ameliorate systemic toxicity from
  - Necrotic tissue (allograft thrombosis)
  - Acute inflammatory state (refractory rejection, necrotizing graft pancreatitis)
  - Sepsis (leak, abscess)
- Discontinue immunosuppression

PATIENT HISTORY AND PHYSICAL FINDINGS

The typical signs and symptoms of pancreas allograft dysfunction are nonspecific and may include nausea and vomiting, fever, abdominal pain and tenderness, elevated serum glucose, amylase/lipase, and leukocytosis.
The time course of signs and symptoms posttransplant are critical in formulating a likely differential diagnosis:
- Within the first week
  - Thrombosis, arterial or venous
  - Ischemia reperfusion injury
  - Acute pancreatitis
- One week to 1 month time period
  - Enteric leak
  - Intraabdominal collection or abscess
  - Bladder leak if bladder-drained graft
  - Acute rejection, especially if recipient sensitized or did not receive depleting antibody induction
- Greater than 1 month from the transplant
  - Acute rejection, especially if recipient received depleting antibody induction
  - Viral infection, particularly CMV
  - Reflux pancreatitis in bladder-drained grafts
The most important finding for allograft thrombosis is sudden onset of new hyperglycemia in the early postoperative period.
- New or sudden onset of hyperglycemia alone within the first week posttransplant may be the only initial clinical sign of arterial or venous thrombosis and mandates immediate further evaluation with diagnostic imaging (pancreas transplant Doppler examination) and usually vascular duplex or CT with IV contrast reexploration.
Abdominal signs and symptoms such as nausea, vomiting, abdominal distension, pain, tenderness, or peritoneal signs are early findings in acute transplant pancreatitis, enteric leak, intraabdominal collection or abscess, and acute rejection. These signs and symptoms may be a late finding in vascular thrombosis, particularly arterial thrombosis.
Systemic signs of infection with fever, tachycardia, hypotension, and leukocytosis are more consistent with enteric leak, intraabdominal collection or abscess, acute rejection, and acute pancreatitis. These signs and symptoms may be a relatively late sign of acute thrombosis due to systemic toxicity from necrotic tissue.
In cases where a closed suction drain was left intraabdominally adjacent to the pancreas allograft at the time of surgery, high amylase in the fluid may suggest acute pancreatitis or enteric leak. Bilious drain output suggests an enteric leak. In cases of bladder-drained pancreas grafts, an elevated drain fluid creatinine compared to serum creatinine suggests a bladder leak (transplant duodenocystostomy leak).
Bladder-drained pancreas grafts may also present with a decrease in urinary amylase.