should have excellent functional status in anticipation of the more extensive surgery and more frequent

complications. Age is not tightly related to outcome, but patients over the age of 60 are carefully

scrutinized.43 A detailed history of the patient’s diabetes and treatment is obtained, including current

glycemic control, hypoglycemic events, secondary complications, insulin requirements, and overall

quality of life. Obesity in and of itself is not a contraindication, as outcomes for carefully selected obese

(BMI >30) recipients are similar to nonobese recipients, although surgical complications and the

likelihood of remaining insulin dependent may be slightly higher.44 Selection practices vary widely—for

some centers, pancreas transplantation is reserved for those with significant complications and poor

glycemic control who have failed alternative treatments, while for others the presence of type 1

diabetes and a full understanding of the risks and benefits are sufficient, with patient preferences

playing a significant role. In general, because of the added need for immunosuppression in PTA, these

diabetes-related criteria are much more stringent than for SPK or PTA, where the risk of

immunosuppression is already assumed by virtue of the kidney transplant.

All candidates, in addition to assessment of the potential benefit of pancreas transplantation, should

have at the least noninvasive cardiac stress testing such as dobutamine stress echocardiography or

adenosine thallium stress scintigraphy. Potential candidates with reversible myocardial defects undergo

coronary angiography, and many centers perform angiography on all candidates. The decision to

perform pretransplantation coronary revascularization must be made with consideration of both

peritransplant mortality and long-term survival. Although survival outcomes are diminished in

recipients with coronary artery disease,45 a history of coronary revascularization is not necessarily a

contraindication; individuals with extensive myocardium at risk and without revascularization options

are frequently excluded.

Screening for peripheral vascular occlusive disease is often performed. Although distal peripheral

vascular occlusive disease is characteristic of longstanding diabetes, aortoiliac disease and femoral

popliteal vascular disease may also be present. Femoral popliteal disease is generally not a

contraindication to transplantation, unless there are clinical signs of arterial insufficiency such as severe

claudication or nonhealing ulcers. The presence of iliac disease is more problematic, as it can

compromise inflow to the transplanted organs or increase the risk for postoperative arterial

complications. In addition, diabetics may have significant vascular calcification which could preclude

transplantation even in the absence of flow abnormalities. Screening for peripheral vascular occlusive

disease, in addition to a thorough physical examination, may include noninvasive flow studies and/or

CT scanning to evaluate vascular calcification. Candidates with a history or examination findings

suggestive of cerebrovascular disease should be screened for hemodynamically significant carotid

occlusive disease.

Other evaluations, as with other types of organ transplants, are tailored to the individual medical

history, and differ among centers. Screening for malignancy commonly includes mammography and pap

smears for women, prostate-specific antigen levels in men, and colonoscopy. Individuals with a prior

history of treated cancer and who are judged to be at low risk for recurrence are usually candidates

following an appropriate disease-free interval. This interval is decreasing as greater experience with

transplantation in individuals with a history of cancer has accumulated, and can be as little as 2 years

for many solid epithelial tumors to none for carcinoma in situ or early prostate cancer.46 Screening for

chronic viral infections such as hepatitis B, hepatitis C, and HIV is commonly performed, and pancreas

transplants in selected individuals with chronic hepatitis are being performed with increasing

frequency.47,48 As with liver and kidney transplantation, early experience with pancreas transplantation

in carefully selected individuals with HIV infection has been encouraging.49 Social work and/or

psychiatric evaluation is performed to rule out psychiatric disease, inadequate social environments, and

other issues that may impact the recipient’s ability to participate in posttransplantation management.

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Figure 40-3. Number of U.S. simultaneous pancreas–kidney (SPK), pancreas after kidney transplantation (PAK), and pancreas

transplantation alone (PTA) pancreas transplants performed by year. (Data from Scientific Registry of Transplant Recipients. 2013

Annual Report. Rockville, MD: Health Resources and Services Administration, Department of Health and Human Services; 2015).

The Kidney–Pancreas Waiting List and Recipients

The number of patients on the waiting list for a simultaneous kidney–pancreas transplant has decreased

from a peak of 2,396 in 2005 to 2,076 in 2012.50 The majority of patients are white (60%), though the

percentages of white candidates is decreasing, while the percentage of African-American (24%) and

Hispanic/Latino patients (13%) continues to increase. The number of patients on the waiting list has

decreased since 2000 for all adult age groups except those in 50 to 64, and the age distribution has

shifted upward. While the majority are ages 35 to 49 (57% in 2012), the percentage who are ages 50 to

64 is increasing (23% in 2012) and the percentage who are ages 18 to 34 (19% in 2012) is decreasing.

The annual death rate on the SPK waiting list was 69 per 1,000 patient years in 2012, compared with 96

in 2006.

The number of SPK transplants performed has declined from 924 in 2006 to 801 in 2012 (Fig. 40-3).

Median times to SPK have increased from 14.8 months for those registered in 2006–2007 to 16.2

months for those registered in 2010–2011. Time to transplant is longer for African-American and

Hispanic/Latino recipients. While the majority of SPK recipients are white (65%) and males (64%), the

percentage of SPK recipients who are African American (20% in 2012) and Hispanic (12% in 2010) in

increasing. The age distribution of recipients parallels that of the waiting list.

The Pancreas Transplant Waiting List and Recipients

The number of patients awaiting isolated pancreas transplants in 2012 is also decreasing, with 413

patients awaiting PTA versus 528 in 2006 and 583 awaiting PAK versus 986 in 2006.50 The increase in

the number of patients waiting for isolated pancreas transplant in the last 5 years is largely due to a

sharp decrease in the numbers of new registrations rather than an increase in transplants performed.

The great majority of patients awaiting isolated pancreas transplants are white (80% for PTA, 75%

for PAK); there have been significant increases in the percentage of African Americans on the PAK and

PTA lists over the last several years. Although women continue to constitute 54% of the PTA waiting

list in 2012, they are only 46% of the PAK waiting list. The majority of patients awaiting both PTA and

PAK are between 35 and 49 years old, but as with SPK candidates, the percentage of older patients

listed for PAK and PTA has increased, with 36% and 30%, respectively, of the waiting list in 2012 being

between the age of 50 and 64 years.

The median time to transplant for PAK has increased over the last 5 years, with the mean waiting

time for candidates registered in 2008–2009 now being 36.9 months. This is greater than the median

time to transplant for SPK registrants. Wait times for PTAs have also increased, nearly doubling since

2007–2011 to 19.1 months for those registered in 2010–2011.

The age and race of recipients of solitary pancreas transplants reflect the waiting list. In 2012, 88% of

PTA and 72% of PAK and recipients were white. More PAK recipients (64%) were male, but more PTA

recipients (63%) were women, and this gender gap has widened in the past 5 years.

Deceased Donor Pancreas Allocation

As with many organs, deceased donor pancreas allocation is determined primarily by geography, with

most organs offered to centers in the Donation Service Area (DSA) of donor origin. The base organ

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allocation unit is the organ procurement organization (OPO) which serves the population within the

DSA. The 58 DSAs are organized into 11 regions, which serve as the second-tier of organ allocation. As

with other organs, pancreata are allocated according to nationally determined policies.51 There is

mandatory sharing of pancreata to highly sensitized candidates that are completely matched to the

donor; beyond this, pancreata are allocated to these pancreas candidates first locally, then regionally,

then nationally based primarily on waiting time.

If the pancreas candidate is an SPK candidate, then a kidney from the same donor is usually also

allocated to the SPK candidate, regardless of the candidate’s place on the kidney waiting list. While such

a policy promotes pancreas utilization, it has been somewhat controversial, since preferential allocation

of kidneys to simultaneous kidney–pancreas (SPK) candidates prevents allocation to kidney-alone

candidates who have generally been waiting longer. Solitary pancreata are more difficult to place

compared with SPK because their outcomes are slightly worse, but are more easily shared voluntarily

since OPOs have no obligation to share kidneys along with pancreas for outside SPK candidates; since

pancreas donors are carefully selected, the kidneys from these donors are usually able to be

transplanted into a local kidney candidate. Thus, shared pancreata are generally restricted to PTA or

PAK candidates.52

Pancreas allocation is also complicated by the fact that the pancreas donor selection criteria for islet

transplant and whole-organ transplant overlap, leading to competition among certain types of organs. In

determining whether a given pancreas will be allocated to a solid organ or islet transplant candidate,

donor age and BMI are considered. Donors under age 50 and with BMI <30 are allocated for wholeorgan pancreas transplant locally. If there is no local acceptance, the pancreas is offered regionally and

then nationally. If there is no candidate for whole pancreas, the pancreas is then allocated for islets. For

donors older than age 50 or with BMI >30, whose pancreata are rarely used for whole-organ

transplant, the organ is first offered for pancreas transplant locally; if there are no local candidates, the

pancreas is then offered for islets.51

Pancreata are significantly underutilized compared to other solid organs such as liver and kidney. As

discussed below, donor selection criteria are more rigorous. Restrictions on cold ischemia time for

whole-pancreas transplantation and particularly for islet transplantation make the placement of

pancreata that are not used by the recovering center difficult. There is significant geographic variation

in pancreas use, which correlates with activity by local transplant centers.53

Donor Evaluation

6 The selection of appropriate pancreas donors is perhaps the most important determinant of successful

pancreas transplantation. Many of the early complications of pancreas transplantation are thought to be

secondary to processes related to organ quality and preservation, rather than the technical conduct of

the recipient operation. While the ideal donor is young, nonalcoholic and nonobese, very few donors

meet this description, and the surgeon frequently needs to consider pancreata from imperfect donors.

Donor selection criteria may vary among surgeons and transplant centers, and may depend upon past

experience, waiting time, and recent outcomes. Primary criteria are the age of the donor, donor BMI,

donor cause of death, and the gross appearance of the organ at the time of recovery. Additional

information that may influence the decision include aspects of the medical and social history, donor

hemodynamics, laboratory values, HLA matching, and anticipated preservation time. As with donor

selection with other organs, the decision-making process often involves consideration of multiple factors

in aggregate.

The importance of donor age on graft outcomes has been confirmed by multiple studies, and the

maximum age threshold is significantly lower than for liver and kidney transplantation.54,55 Many

centers use an age threshold, which may range from 40 to 50, above which donors are selected very

carefully. The mechanism by which age affects outcomes is not firmly established: age appears to

influence both early technical and late graft loss.55,56

Donor BMI has been found to be a determinant of graft failure by single-center and transplant registry

analyses.57,58 Very few pancreata from donors with BMI greater than 30 are used for solid-organ

transplant, and are more likely to be recovered for islet transplant.52 Interestingly, for overweight but

not obese donors (BMI 25 to 30), a large single-center study found a higher rate of technical failure for

donors who also had a cerebrovascular attack as cause of death.57 It is not known whether associations

with BMI relate to fatty infiltration of the pancreas or by a separate mechanism.

The circumstances of death and the condition of the donor influence donor selection. Pancreata from

donors with stroke as a cause of death have reduced graft survival. Although experience from donors

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